NLE Immune System & Immunologic Disorders — Immunity, Hypersensitivity and Allergic DisordersStudy Notes

Immunity is the body's capacity to recognize, resist, and defend against pathogens and foreign substances (antigens). The immune system operates through two complementary but distinct pathways: innate immunity and adaptive immunity. Innate (Natural, Nonspecific) Immunity is present from birth and acts as the body's first line of defense. It responds the same way to any invader without prior sensitization. Key components include physical barriers (skin and mucous membranes), phagocytic cells (neutrophils, macrophages), the inflammatory response, and the complement system. The advantage of innate immunity is its immediacy—it provides instant protection. However, it has no memory, so re-exposure to the same pathogen produces the same level of response rather than an enhanced one. In Philippine clinical practice, you will assess innate immunity through signs of inflammation (redness, warmth, swelling, pain) and fever, particularly in NCM Level 2 (Community Health Nursing) and Level 3 (Hospital Nursing) settings. Adaptive (Acquired, Specific) Immunity develops after exposure to a specific antigen and creates immunologic memory. It is slower to develop initially but produces a faster, stronger response upon re-exposure. The adaptive immune system has two arms: (1) Humoral immunity, mediated by B lymphocytes that produce antibodies (immunoglobulins), and (2) Cell-mediated immunity, mediated by T lymphocytes (helper CD4+ cells and cytotoxic CD8+ cells). The lag time for the first adaptive response is typically 7-14 days, but secondary responses occur within hours because of memory B and T cells. This distinction is crucial for understanding vaccine timing and prophylaxis in the Philippine context, where immunization programs (EPI—Expanded Program on Immunization) rely on the adaptive immune system to build population-level protection.

Antibodies are the key players in humoral immunity. They are produced by plasma cells (differentiated B lymphocytes) and belong to five classes, each with distinct structures and functions. Understanding immunoglobulins is essential for the NLE because they are directly involved in hypersensitivity reactions and vaccine responses. IgG (Immunoglobulin G) is the most abundant antibody, comprising about 75% of total serum immunoglobulin. It is small enough to cross the placental barrier, providing passive immunity to the newborn during the first months of life—this is why maternal antibodies protect infants against diseases the mother has been exposed to. IgG is responsible for the secondary (memory) immune response, meaning it dominates after re-exposure to an antigen (such as a booster vaccine). It activates complement efficiently and opsonizes (marks) pathogens for phagocytosis. Clinically, elevated IgG after infection indicates past or recent exposure; in vaccine responses, rising IgG titers confirm successful immunization. IgM (Immunoglobulin M) is the largest antibody—it is a pentamer (five units joined together)—and it is the first antibody the body produces during an acute (primary) infection. Because of its large size, it cannot cross the placenta. Detecting IgM in a patient's serum indicates an acute or recent infection; for example, IgM positivity in a dengue serology panel in the Philippines suggests acute dengue rather than past infection. IgM is very effective at activating complement and agglutinating (clumping) pathogens, but it is short-lived, persisting only weeks to months. IgA (Immunoglobulin A) exists in two forms: serum IgA (monomer) and secretory IgA (dimer). Secretory IgA is found abundantly in mucous secretions—saliva, tears, breast milk, mucus from respiratory and gastrointestinal tracts. It protects mucosal surfaces by binding pathogens and preventing their attachment to epithelial cells. This is why breastfeeding provides mucosal immunity to infants through IgA in breast milk; this is especially important in Philippine settings where infant formula safety and refrigeration may be limited. IgA deficiency is the most common primary immunodeficiency and is usually asymptomatic but can predispose to recurrent sinusitis and gastrointestinal infections. IgE (Immunoglobulin E) is present in tiny amounts in normal serum (less than 0.01% of total antibody), but it is highly important. IgE binds tightly to mast cells (in tissue) and basophils (in blood), and when an allergen cross-links IgE on the surface of these cells, rapid degranulation occurs, releasing histamine and other inflammatory mediators. This is the mechanism of type I hypersensitivity (immediate/allergic/anaphylactic reactions). IgE-mediated reactions occur within seconds to minutes. In clinical practice, elevated serum IgE and specific IgE testing (RAST or ImmunoCAP) help diagnose allergies; total serum IgE is nonspecific but supports allergic disease in the context of clinical symptoms. IgD (Immunoglobulin D) exists primarily as a surface receptor on B lymphocytes and plays a role in B-cell activation and differentiation. Its role in serum is poorly understood, and it is rarely tested clinically. It is the least clinically relevant of the five immunoglobulins for NLE purposes.

The PRC Board of Nursing emphasizes the distinction between active and passive immunity, and between natural and artificial acquisition. This is a high-yield NLE concept because it directly applies to vaccine counseling, disease prevention, and immunoglobulin therapy in clinical practice. Active Immunity occurs when the person's own immune system produces antibodies and develops immunologic memory in response to an antigen. The response is slower (taking days to weeks for primary response) but long-lasting (years to lifetime) because memory B and T cells persist. Active immunity is further divided into natural (acquired by having the actual disease) and artificial (acquired by vaccination with attenuated, killed, or component antigen). Natural Active Immunity develops when a person is infected with the actual pathogen, becomes ill, and the body mounts a primary and then memory response. For example, having chickenpox creates lifelong immunity to varicella-zoster virus in most people. The advantage is robust, durable immunity; the disadvantage is the risk of severe disease or death during the acute infection. In Philippine public health (NCM Level 2), natural active immunity from measles infection was historically common but caused preventable deaths; vaccination now provides active immunity without the disease risk. Artificial Active Immunity is conferred by vaccination—administration of an antigen (live-attenuated, inactivated, toxoid, or recombinant) that stimulates the immune system to produce antibodies and memory without causing disease. Examples include the MMR vaccine (live-attenuated), hepatitis B vaccine (recombinant), tetanus toxoid (inactivated toxin), and polio vaccine (either live oral or inactivated injectable). The response is slower than natural infection and may require booster doses, but it provides the benefit of protection without disease risk. In the Philippines, the EPI includes routine vaccination for diphtheria-pertussis-tetanus (DPT), polio, measles, hepatitis B, and others. Nurses at all NCM levels are responsible for promoting vaccination and educating families about the importance of completing the full schedule. Passive Immunity occurs when ready-made antibodies are transferred to a person, providing immediate protection. However, because the person's own immune system did not make these antibodies, no memory is created—the protection is temporary, lasting weeks to months as the borrowed antibodies are metabolized. Passive immunity is divided into natural and artificial. Natural Passive Immunity includes maternal antibodies transferred across the placenta (primarily IgG) and antibodies in breast milk (primarily secretory IgA). A newborn is protected against diseases the mother has immunity to; this protection wanes as maternal antibodies degrade, typically by 6-12 months. This is why immunization schedules begin in infancy—as maternal immunity fades, active immunity from vaccination takes over. In Filipino maternal-child health programs (NCM Level 2), nurses counsel mothers on the importance of antenatal screening for immunity (especially for tetanus and rubella) to ensure passive protection of the newborn. Artificial Passive Immunity is the injection of ready-made antibodies (immune serum, immunoglobulin, or antivenom) to provide immediate protection in a high-risk exposure or acute situation. Examples include tetanus immunoglobulin (TIG) given after a dirty wound injury, hepatitis B immunoglobulin (HBIg) given after needlestick exposure, rabies immunoglobulin (RIG) after a potential rabies exposure, and antivenom after a snake bite. In the Philippines, artificial passive immunization is critical in rural and remote areas where access to active vaccination may be limited and where rabies, snake bite, and tetanus remain public health threats. The onset is immediate (protection begins within hours), but duration is short (2-3 weeks to a few months). Importantly, passive immunoglobulin therapy for certain conditions (e.g., immunodeficiency) is given as IVIG (intravenous immunoglobulin) infusions. The Core Rule for NLE: Active immunity is slow to develop but durable because it creates memory; passive immunity is fast but temporary because it relies on externally supplied antibodies that the body eventually breaks down. This distinction is tested repeatedly in the NLE, especially in questions about vaccine timing, booster schedules, and post-exposure prophylaxis.

Hypersensitivity is an exaggerated or inappropriate immune response to an antigen that results in tissue damage rather than protection. The Gell and Coombs classification (1963) describes four types (I, II, III, IV), remembered by the acronym ACID: Type I = Anaphylactic/Allergic (IgE-mediated); Type II = Cytotoxic (IgG/IgM-mediated); Type III = Immune complex; Type IV = Delayed (T-cell-mediated). Understanding these four types is fundamental to NLE success and safe clinical practice. Type I — Immediate (Anaphylactic/Allergic) Hypersensitivity is mediated by IgE. The mechanism occurs in two phases. In the sensitization phase (first exposure), the person encounters an allergen (a harmless substance treated as foreign by the immune system). IgE antibodies are produced and bind tightly to mast cells in tissues and basophils in blood. No clinical reaction occurs during sensitization; the person is now "allergic" but asymptomatic. In the re-exposure phase (second or subsequent encounter with the same allergen), the allergen binds and cross-links IgE on mast cells and basophils, triggering rapid degranulation. Within seconds to minutes, preformed mediators (histamine, tryptase, heparin) and newly synthesized mediators (leukotrienes, prostaglandins, thromboxanes) flood the tissues and blood. The result is vasodilation (increased blood vessel permeability), bronchoconstriction (airway spasm), smooth muscle contraction (urticaria, angioedema), and increased mucus secretion. Type I reactions occur within minutes of exposure. Common allergens include plant pollens (allergic rhinitis/hay fever), food (peanuts, shellfish, eggs, milk), medications (penicillin), insect venom (bee sting), and latex. Manifestations range from mild (localized urticaria, sneezing) to severe (anaphylaxis with airway obstruction and cardiovascular collapse). In the Philippines, allergic rhinitis and asthma are common in urban areas with high pollution; peanut allergy is a growing concern, especially in children. Anaphylaxis is the life-threatening end of the type I spectrum and is discussed in detail in a separate section. Type II — Cytotoxic Hypersensitivity is mediated by IgG or IgM antibodies directed against antigens on the surface of a person's own cells (autoimmunity) or foreign cells (e.g., transfused RBCs). The antibodies bind to the cell surface antigen, activating the classical complement cascade or engaging Fc receptors on phagocytes (macrophages, neutrophils), leading to cell destruction and removal. Type II reactions are not immediate but develop over hours to days. Classic examples include: (1) ABO-incompatible blood transfusion reaction—IgG and IgM antibodies against incompatible RBC antigens activate complement and cause rapid RBC destruction (hemolysis), releasing hemoglobin that damages the kidneys; (2) Rh incompatibility and hemolytic disease of the newborn (erythroblastosis fetalis)—an Rh-negative mother sensitized by Rh-positive fetal blood during pregnancy produces IgG antibodies that cross the placenta and attack fetal RBCs; (3) Autoimmune hemolytic anemia—the person's own antibodies attack the person's own RBCs; (4) Immune thrombocytopenia (ITP)—antibodies against platelet antigens cause destruction and thrombocytopenia; (5) Goodpasture syndrome—antibodies against lung and kidney basement membrane cause pulmonary hemorrhage and glomerulonephritis; (6) Graves disease—antibodies to TSH receptors on thyroid cells cause thyroid overactivity and hyperthyroidism; (7) Myasthenia gravis—antibodies to acetylcholine receptors at the neuromuscular junction cause muscle weakness. In Philippine clinical practice, particularly in hospital nursing (NCM Level 3), careful blood typing and cross-matching prevent ABO transfusion reactions; monitoring women of childbearing age for Rh status and providing RhIG (anti-D immunoglobulin) after delivery of an Rh-positive infant prevents Rh sensitization in future pregnancies. Type III — Immune Complex Hypersensitivity occurs when antigen-antibody complexes form in the circulation and deposit in tissues, especially at the junction of blood vessels and tissues (like the glomerular basement membrane in the kidneys). The deposited complexes activate complement, recruiting macrophages and neutrophils that release enzymes and cytokines, causing inflammation and tissue damage. Type III reactions develop over hours to days. Causes include: (1) Systemic lupus erythematosus (SLE)—autoimmune disease with deposition of immune complexes in skin, joints, kidneys; (2) Rheumatoid arthritis—immune complexes in synovial joints cause chronic inflammation; (3) Acute post-streptococcal glomerulonephritis—occurs 1-2 weeks after Group A streptococcal infection (e.g., strep throat); immune complexes deposit in kidney glomeruli causing hematuria and hypertension; (4) Serum sickness—a reaction to foreign proteins (e.g., antitoxins, certain drugs) with systemic symptoms (fever, rash, arthralgia, lymphadenopathy); (5) Arthus reaction—a localized type III reaction seen at sites of repeated vaccination. In the Philippines, post-streptococcal glomerulonephritis remains common in children in areas with high streptococcal infection burden; nurses in community settings educate families on early recognition of strep throat and complete antibiotic therapy to prevent complications. Type IV — Delayed (Cell-Mediated) Hypersensitivity is the only type that is not antibody-mediated; instead, sensitized T lymphocytes (specifically, Th1 helper cells and cytotoxic T cells) react with antigen-presenting macrophages and release cytokines (IFN-gamma, TNF-alpha, IL-2) that recruit more macrophages and cause inflammation. Because this is a cellular process requiring T-cell proliferation, it is slow—reactions develop over 24-72 hours (hence "delayed"). Type IV hypersensitivity is responsible for: (1) Tuberculin (PPD/Mantoux) skin test—in a tuberculin-sensitized person, intradermal tuberculin protein causes a T-cell response with induration (hardening) and erythema 48-72 hours later; a positive test indicates previous TB infection or vaccination (BCG); (2) Contact dermatitis—from environmental allergens (poison ivy, nickel in jewelry, latex gloves)—an eczematous rash develops 24-48 hours after contact; (3) Transplant/graft rejection—T cells recognize foreign MHC antigens on transplanted tissue and mount a cellular attack; (4) Granulomatous reactions—chronic type IV responses in conditions like tuberculosis (where macrophages form epithelioid granulomas around TB bacilli) and sarcoidosis. In Filipino healthcare, the Mantoux test is used to diagnose TB infection; delayed reaction (induration ≥5 mm in high-risk patients, ≥10 mm in others) indicates TB exposure. Contact dermatitis from latex gloves is becoming more recognized and requires use of latex-free supplies for sensitized individuals. In the Philippines' tropical climate, poison ivy exposure is less common, but allergic contact dermatitis from plants, cosmetics, and metals is frequent.

An allergy is a type I hypersensitivity reaction to an ordinarily harmless environmental antigen (allergen). The allergen itself is not inherently dangerous—the danger comes from the person's exaggerated IgE-mediated response. Allergies are common in Filipino populations, particularly allergic rhinitis (hay fever) and allergic asthma, especially in urban areas with pollution and high humidity favoring dust mite and mold proliferation. Common Allergens include environmental (pollen, dust mites, mold spores, animal dander, cockroaches), food (peanuts, tree nuts, shellfish, eggs, milk, soy, fish), medications (penicillin and beta-lactams, NSAIDs, ACE inhibitors), insect venom (bee, wasp, ant stings), occupational (latex for healthcare workers), and others. In the Philippine context, cockroach allergy is particularly prevalent in older buildings and informal settlements; mold allergy is common in monsoon season; and food allergies are increasing as Western dietary habits spread. Notably, peanut allergy in children is becoming more common and can be severe. Clinical Manifestations vary by route of exposure and severity: Respiratory symptoms occur with airborne allergens: sneezing, rhinorrhea (nasal discharge), nasal congestion, itching of nose/palate, wheezing, cough, dyspnea (in allergic asthma). Seasonal patterns (hay fever in specific seasons) or perennial symptoms (year-round, suggesting dust mite or mold allergy) help identify the allergen. Skin manifestations include urticaria (hives—raised, pruritic wheals), pruritus (itching), erythema (redness), and angioedema (deeper swelling of lips, eyelids, tongue, face). Angioedema can be dangerous if it involves the larynx (laryngeal angioedema), risking airway obstruction. Gastrointestinal symptoms occur with food allergen ingestion: nausea, vomiting, cramping, diarrhea, abdominal pain. Oral allergy syndrome (tingling of lips and throat) can occur with fresh fruits and vegetables in pollen-sensitized individuals. Ocular symptoms: itching, tearing, conjunctivitis from environmental allergen exposure. Assessment in the Clinical Setting (NCM Level 3 — Hospital Nursing): 1. Obtain a detailed allergy history: Identify the specific allergen, timing of symptoms in relation to exposure (e.g., symptoms within 15 minutes of eating peanuts suggests IgE-mediated allergy), prior reactions and their severity, whether symptoms are improving with avoidance, any medications used for relief, and family history of atopy (genetic predisposition to allergies). 2. Screen for drug allergies: Always ask about known drug allergies before administering any medication. Distinguish between true allergy (IgE-mediated reaction) and side effects or intolerance (e.g., GI upset from antibiotics is not an allergy). Document the type of reaction (urticaria, anaphylaxis, rash) and timeframe. 3. Assess severity: Mild allergies (localized urticaria, sneezing) vs. moderate (generalized urticaria, angioedema) vs. severe (anaphylaxis, airway involvement). Ask if the patient has ever needed emergency care or epinephrine. 4. Review current medications: Some medications (beta-blockers) worsen anaphylaxis outcomes; ACE inhibitors increase angioedema risk with certain allergens. 5. Perform physical examination: Note skin manifestations (urticaria, angioedema), respiratory status (wheezing, stridor), vital signs (tachycardia, hypotension in severe reactions). Diagnostic Tests: 1. Skin Testing (Scratch Test, Prick Test, Intradermal Test): Small amounts of allergen extract are applied to or injected into the skin. In an allergic person, IgE on mast cells in the skin reacts with the allergen, causing local mast cell degranulation and a wheal-and-flare reaction (a raised bump surrounded by redness) within 15 minutes. The size of the wheal correlates with sensitization. Skin testing is rapid (results in 15-20 minutes), specific, and cost-effective. Critical nursing consideration: Emergency equipment (epinephrine, oxygen, IV access) must be immediately available because skin testing can trigger anaphylaxis in highly sensitized individuals. Avoid skin testing during acute exacerbations or if the patient is taking antihistamines (which suppress the response). In the Philippines, skin testing is available in major hospitals and allergy clinics but may be limited in provincial areas; nurses must know where to refer patients for testing. 2. Serum-Specific IgE Testing (RAST—Radioallergosorbent Test, or ImmunoCAP): Blood is drawn and tested for IgE antibodies against specific allergens. Results are returned in days to weeks. This test is useful when skin testing is contraindicated (patient has dermatographism—easily bruising skin; or is on medications that interfere). It is more expensive than skin testing and not as rapid, but it does not carry the anaphylaxis risk. Results are reported as IU/mL or RAST classes (0-6, higher = more sensitized). 3. Complete Blood Count (CBC): Eosinophilia (elevated eosinophil count, >400-500 cells/µL) supports an allergic process, though it is nonspecific. 4. Total Serum IgE: Elevated total IgE (>150 IU/mL) supports allergic disease but is nonspecific; many conditions elevate total IgE (parasitic infections, certain lymphomas). Specific IgE testing is more clinically useful. Pharmacologic Management of Allergies: 1. Antihistamines (H1 Receptor Antagonists): These block histamine binding to H1 receptors on mast cells, endothelial cells, and smooth muscle, preventing vasodilation, increased permeability, and bronchoconstriction. First-generation antihistamines (e.g., diphenhydramine, chlorpheniramine) are lipophilic and cross the blood-brain barrier, causing sedation, anticholinergic effects (dry mouth, urinary retention, tachycardia), and impaired cognitive function. They have a rapid onset (15-30 minutes) and are useful in acute allergic reactions, but sedation is a major drawback. In the Philippines, diphenhydramine (Benadryl) is widely available over-the-counter and often used; caution patients against driving or operating machinery. They are also useful for motion sickness and as a sleep aid (common in Filipino households). Second-generation (non-sedating) antihistamines (e.g., cetirizine, loratadine, fexofenadine) have a higher molecular weight and do not cross the blood-brain barrier, so they are non-sedating and better tolerated for long-term use. They have a slightly slower onset (30-60 minutes) but similar efficacy. These are preferred for chronic allergic rhinitis and asthma. In the Philippines, cetirizine (Piriteze) and loratadine (Claritin) are popular over-the-counter options. Note: Antihistamines are effective for urticaria, rhinitis, and mild symptoms but are NOT sufficient for anaphylaxis—epinephrine is the first-line drug for anaphylaxis. 2. Corticosteroids: Reduce inflammation and suppress immune responses. For allergies, they are used for moderate-to-severe or chronic disease. Intranasal corticosteroids (e.g., fluticasone, mometasone) are first-line for allergic rhinitis; they reduce inflammation in the nasal mucosa and improve congestion, rhinorrhea, and sneezing. Local delivery minimizes systemic side effects. Teach patients that onset is 1-2 weeks and that regular use is needed for efficacy. Systemic corticosteroids (e.g., prednisone, methylprednisolone) are used for severe or acute allergic reactions and for acute exacerbations of allergic asthma. Short courses (3-7 days) are generally safe. Critical nursing point: Do not abruptly stop systemic corticosteroids; taper the dose. Prolonged use causes immunosuppression, adrenal suppression, hyperglycemia, osteoporosis, and other side effects. 3. Mast Cell Stabilizers (e.g., cromolyn sodium): Prevent mast cell degranulation. Used prophylactically for allergic rhinitis and asthma; less effective for acute symptoms. Onset is 2-4 weeks. Less commonly used now with the availability of intranasal corticosteroids. 4. Leukotriene Modifiers (e.g., montelukast, zafirlukast): Block leukotriene receptors or inhibit leukotriene synthesis. Leukotrienes are inflammatory mediators released by mast cells and eosinophils. These drugs are useful for allergic asthma and allergic rhinitis, especially when asthma and rhinitis co-exist. Onset is days to weeks; used as prophylaxis, not for acute symptoms. 5. Decongestants (e.g., pseudoephedrine, phenylephrine): Alpha-adrenergic agonists that cause vasoconstriction and reduce nasal congestion. Used short-term (max 3-5 days) to avoid rebound congestion (rhinitis medicamentosa). Caution in hypertension and tachycardia. Not recommended in children <12 years. 6. Immunotherapy (Allergen Immunization): Long-term treatment involving gradual exposure to increasing allergen doses to desensitize the immune system and reduce IgE while increasing IgG (blocking antibody). Useful for pollen, mold, dust mite, and animal allergen allergies. Takes months to years. High cost and requires regular clinic visits; less commonly available in provincial Philippine settings. Nursing Management and Patient Education: 1. Assess and document all allergies and drug sensitivities on patient admission; verify at every medication administration. 2. Teach allergen avoidance: Identify and avoid the offending allergen; read food labels; inform all healthcare providers of allergies; avoid medications with cross-reactivity (e.g., if penicillin-allergic, caution with cephalosporins if possible). 3. Teach proper medication use: Antihistamines are taken regularly for chronic allergies, not just when symptoms flare; intranasal corticosteroids require consistent use for effectiveness; leukotriene modifiers are preventive, not acute. 4. Teach recognition of early symptoms and when to seek emergency care: Progression from localized symptoms (itching, urticaria) to systemic symptoms (dyspnea, hypotension) warrants emergency evaluation. 5. Teach self-care measures: Avoid allergen triggers, keep environment clean, use air filters, avoid outdoor activities during high pollen seasons, shower after outdoor exposure. 6. In NCM Level 2 (Community Health Nursing), nurses educate families on recognizing allergies in children, proper use of over-the-counter antihistamines, and when to refer for specialist evaluation.

Anaphylaxis is a severe, rapid, systemic type I hypersensitivity reaction that is the most life-threatening immune emergency. It is one of the most heavily tested topics in the NLE because recognition and immediate management are critical to patient survival. The Nursing Practice Act (RA 9173) holds nurses accountable for recognizing medical emergencies and initiating appropriate interventions within the scope of nursing practice. Definition and Pathophysiology: Anaphylaxis is a rapid, systemic release of mast cell and basophil mediators (primarily histamine, tryptase, and newly synthesized leukotrienes, prostaglandins) triggered by IgE cross-linking on mast cells and basophils. The massive surge in mediators causes acute vasodilation (drop in systemic vascular resistance), increased capillary permeability (fluid shifts from intravascular to interstitial space—distributive shock), bronchoconstriction (airway narrowing), laryngeal edema (airway obstruction), and smooth muscle contraction (urticaria, cramping). The result is rapid onset of hypotension, hypoxemia, and potentially cardiovascular collapse and death within minutes if untreated. Common Triggers (Allergens): 1. Foods: Peanuts, tree nuts (almonds, cashews, walnuts), shellfish (shrimp, crab, lobster), eggs, milk, soy, fish. In the Philippines, peanut and shellfish allergies are increasingly recognized, especially in children. 2. Medications: Penicillin and beta-lactam antibiotics (classic), cephalosporins (cross-reactivity ~1-3% with penicillin allergy), NSAIDs, aspirin, ACE inhibitors, vancomycin, chemotherapy agents. Anaphylaxis to penicillin occurs in 1-2% of exposed patients and is the most common drug-induced anaphylaxis. 3. Insect Venom: Hymenoptera (bees, wasps, hornets, yellow jackets, fire ants). A single sting in a sensitized person causes systemic anaphylaxis; reactions to subsequent stings are often more severe. In the Philippines, fire ant stings in agricultural and rural areas are a recognized concern. 4. Latex: From natural rubber latex in gloves, catheters, and medical equipment. Health-care workers and patients with spina bifida (repeated catheterizations) are at high risk. Cross-reactivity with banana, avocado, kiwi, and chestnut (latex-fruit syndrome). 5. Blood Products and Plasma Expanders: IgA-deficient patients can develop anaphylaxis to plasma transfusions containing IgA. 6. Radiocontrast Media: Iodinated contrast agents used in imaging; more common in patients with prior contrast exposure and in those on beta-blockers (which impair epinephrine response). 7. Immunizations and Biologics: Rare but documented with vaccines, monoclonal antibodies, and serum products. 8. Exercise-Induced Anaphylaxis: Triggered by exercise, sometimes combined with food ingestion or NSAIDs; rare but underrecognized. Clinical Presentation and Recognition: Onset is rapid—within seconds to 30 minutes of exposure, most commonly within 5-15 minutes. Late-onset reactions (>30 minutes) are rare. The early phase (prodromal phase) may include: - Sense of impending doom, anxiety, or flushing - Itching (pruritus), particularly of palms, soles, and genitals - Urticaria (raised, pruritic wheals) and erythema - Angioedema (non-pitting swelling of lips, eyelids, tongue, face) As the reaction progresses, multi-system involvement becomes evident: Airway and Breathing Manifestations (Priority—Life-Threatening): - Throat tightness or choking sensation - Hoarseness (from laryngeal edema) - Stridor (high-pitched breathing sound indicating upper airway obstruction) - Laryngeal edema (swelling of the larynx that can progress to complete airway obstruction) - Wheezing (from bronchospasm) - Dyspnea (shortness of breath) - Chest tightness or pain - Bronchospasm with cough - Respiratory distress, accessory muscle use, inability to speak in full sentences **Airway obstruction from laryngeal edema is the leading cause of death in anaphylaxis.** Circulation Manifestations (Shock): - Tachycardia (rapid heart rate, often >100 bpm as compensation for low blood pressure) - **Hypotension** (the hallmark of anaphylaxis; SBP may drop to <90 mmHg) - Dizziness, lightheadedness, syncope (fainting from cerebral hypoperfusion) - Chest pain or palpitations - Cool, clammy skin from vasoconstriction and poor perfusion - Shock (pale, diaphoretic, confused, weak pulse) Gastrointestinal Manifestations: - Nausea, vomiting - Cramping, abdominal pain - Diarrhea Neurologic Manifestations: - Confusion, altered mental status - Loss of consciousness (from hypotension and/or hypoxemia) - Seizures (rare, from severe cerebral hypoperfusion) Biphasic Anaphylaxis: In 5-15% of anaphylaxis cases, a **biphasic reaction** (two-phase reaction) occurs. The initial reaction resolves or partially resolves, then 1-12 hours later (average 8 hours, but can be up to 72 hours), a second wave of symptoms occurs without re-exposure to the allergen. The second phase may be as severe as or more severe than the first. This is why patients are observed in hospital for several hours after anaphylaxis, even if the initial reaction seems mild or resolves quickly. All anaphylaxis patients require hospital observation. Nursing Management and Immediate Interventions (The NLE's Top Priority Topic): The mnemonic for anaphylaxis management is **ABC-ED: Airway, Breathing, Circulation, Epinephrine, Disposition**. However, the single most important **drug** is **epinephrine**, given immediately—within the first few minutes of recognizing anaphylaxis. **Step 1: Administer Epinephrine Immediately (IM)** Epinephrine is the first-line, life-saving drug for anaphylaxis. It reverses all the pathophysiologic processes: it causes vasoconstriction (raising blood pressure), bronchodilation (opening airways), reverses mast cell degranulation and mediator release, and reverses laryngeal edema. **Dosing (Critical for NLE):** - **Adult: 0.3-0.5 mg of 1:1000 (1 mg/mL) solution intramuscularly (IM)** - **Pediatric: 0.01 mg/kg IM, up to 0.3 mg for children <30 kg** - **Route: IM (preferably anterolateral thigh—vastus lateralis), NOT intravenous (IV) for the initial dose** - **Repeat: Every 5-15 minutes as needed if symptoms persist or recur** **Why IM over IV?** IM epinephrine has a more sustained effect and is safer in terms of dysrhythmia risk. IV epinephrine (1:10,000 concentration, diluted) is reserved for cardiac arrest or profound hypotension refractory to IM dosing, and must be given slowly with cardiac monitoring. **Why 1:1000 (1 mg/mL)?** This is the standard concentration for anaphylaxis. Concentration 1:10,000 (0.1 mg/mL) is for IV use in cardiac arrest, not for anaphylaxis IM injection. **Do not confuse concentrations—this is a common error leading to underdosing or overdosing.** **Why the anterolateral thigh?** The vastus lateralis muscle in the thigh has the best blood supply for rapid absorption; it is easily accessible through clothing; and it is the preferred site for IM epinephrine in both adults and children. (The deltoid or gluteus can be used as alternative sites, but thigh is preferred.) Immediate Symptomatic Response: Within 5-10 minutes of IM epinephrine, most patients show improvement: blood pressure rises, respiratory distress eases, urticaria and angioedema begin to resolve, and anxiety decreases. **Step 2: Maintain a Patent Airway** - Position the patient supine with legs elevated (to promote venous return and support blood pressure), UNLESS the patient is having difficulty breathing—then allow sitting upright to ease breathing. - Administer **high-flow oxygen** (O2 via non-rebreather mask at 10-15 L/min or nasal cannula at 6 L/min) to maintain SpO2 ≥94%. - Be prepared for airway compromise: have suction equipment, bag-valve-mask, and emergency intubation equipment at the bedside. - If laryngeal edema is severe and airway obstruction is imminent, emergency airway management (intubation or emergency cricothyrotomy) may be needed; this requires immediate physician/anesthesiologist presence. - Continuously reassess airway status (listen for stridor, assess ability to swallow, observe accessory muscle use). **Step 3: Establish IV Access and Give Fluids** - Start two IV lines (14-16 gauge catheters) for medication and fluid administration. - Administer rapid bolus of isotonic crystalloid (normal saline 0.9% or Lactated Ringer's) at 20 mL/kg over 15-30 minutes to restore intravascular volume and raise blood pressure. (For a 70-kg adult, initial bolus is 1400 mL.) - Continue fluid administration to maintain systolic blood pressure ≥100 mmHg and urine output ≥0.5 mL/kg/hr. - Monitor for fluid overload if copious fluids are given; watch for pulmonary edema. **Step 4: Remove or Stop the Trigger (Allergen)** - If the allergen is an IV medication or blood product, stop the infusion immediately. - If the allergen is an insect sting, remove the stinger by scraping (not pinching, which releases more venom). - If the allergen is oral (food), rinse the mouth and administer activated charcoal if appropriate (though time is usually short for absorption). **Step 5: Adjunct Medications** NOTE: These are secondary agents and are NOT substitutes for epinephrine. They do not replace epinephrine and should not delay epinephrine administration. **Antihistamines (H1 Receptor Antagonist):** - Diphenhydramine 25-50 mg IM or IV, OR - Cetirizine or loratadine 10 mg PO - Onset is 15-30 minutes; helps with urticaria and itching but does NOT reverse airway obstruction or hypotension—too slow for acute symptoms. **H2 Blockers:** - Ranitidine 50 mg IV or famotidine 20 mg IV - Blocks H2 receptors to reduce gastric acid and support H1 blockade; rarely used now due to ranitidine withdrawal, but famotidine or other H2 blockers may be used. **Corticosteroids:** - Hydrocortisone 50-100 mg IV or methylprednisolone 125 mg IV - Onset is 4-6 hours; prevents and reduces the severity of biphasic reactions; does not treat acute symptoms. - Given to all anaphylaxis patients to reduce late-phase reactions. **Bronchodilators (if bronchospasm persists):** - Nebulized salbutamol/albuterol (2.5-5 mg) or epinephrine nebulization (1:1000, 0.5 mL in 3 mL saline) - Treat persistent wheezing and bronchospasm not immediately relieved by epinephrine. **Vasopressors (if hypotension persists despite fluids and epinephrine):** - Norepinephrine or dopamine infusion may be needed for ongoing shock; requires ICU monitoring. **Step 6: Continuous Monitoring** - Monitor vital signs (BP, HR, RR, temp) every 5-15 minutes until stable, then every 30-60 minutes. - Monitor oxygen saturation continuously; keep SpO2 ≥94%. - Continuous cardiac monitoring (ECG) to detect dysrhythmias (epinephrine can cause tachycardia or dysrhythmias). - Monitor mental status; altered mental status suggests hypoxemia or hypoperfusion. - **Observe for biphasic reaction:** Keep patient in hospital for at least 4-24 hours (longer if severe first reaction); a second wave of symptoms can occur without re-exposure. **Step 7: Definitive Care and Disposition** - All anaphylaxis cases require hospital admission for observation and further management. - Admit to emergency department, ICU, or high-dependency unit depending on severity. - Continue monitoring for biphasic reactions. - Identify the allergen if possible (food history, medication review, exposure history). - Educate patient on allergen avoidance and prescribe epinephrine auto-injector before discharge. Post-Anaphylaxis Patient Education and Prevention: 1. **Epinephrine Auto-Injector (EpiPen, Adrenaline Auto-Injector):** - Prescribe two auto-injectors (0.3 mg for adults, 0.15 mg for children <30 kg). - Teach patient how to use: Remove from carrier tube, remove blue safety cap, swing and push the orange tip firmly into the outer thigh (can be done through clothing) until click is heard, hold for 3 seconds, remove and massage thigh for 10 seconds. Some newer injectors (Auvi-Q, newer EpiPens) have verbal instructions. - Patient must carry auto-injector at all times and know where it is. - Educate that epinephrine is used for any symptoms consistent with anaphylaxis—do not wait for severe symptoms. - After using auto-injector, **immediately call emergency services (911 or local equivalent) and go to the nearest hospital**, even if symptoms improve. (Biphasic reactions possible; IV medications and observation needed.) - Refresh training every visit; replace auto-injector before expiration date (typically annually). - In the Philippines, availability of auto-injectors is limited; some are imported at high cost; cost may be a barrier for poor families. Nurses should advocate for patient access and discuss alternatives if auto-injectors are unavailable. 2. **Allergen Avoidance:** - Strictly avoid the known allergen. - Read all food labels for allergen content; inquire about ingredients when eating out. - Inform all healthcare providers, dentists, and other professionals of the allergy. - Avoid medications with cross-reactivity (e.g., if penicillin-allergic, use caution with cephalosporins). - For food-allergic patients, family members and caregivers must be educated on ingredients and preparation to prevent accidental exposure. - In school or workplace, inform supervisors and colleagues so they can assist in an emergency. 3. **Medical Alert Identification:** - Wear a medical-alert bracelet or necklace identifying the allergy (e.g., "ANAPHYLAXIS TO PEANUTS"). - Carry a wallet card listing allergies and emergency contacts. - This ensures that emergency responders and healthcare workers can quickly identify the allergy if the patient is unconscious or unable to communicate. 4. **Recognition of Early Symptoms:** - Educate on early signs (itching, urticaria, throat tightness) so epinephrine can be used early, before airway obstruction or shock develops. - Teach that symptoms progress rapidly and that early use of epinephrine is life-saving. 5. **Seek Emergency Care After Every Auto-Injector Use:** - Emphasize that a biphasic reaction is possible hours after the initial reaction. - Even if symptoms improve after using epinephrine, the patient must go to the hospital for monitoring, observation, and adjunct medications (IV antihistamines, corticosteroids). Nursing Responsibilities in Anaphylaxis: In the emergency and hospital setting (NCM Level 3): - Recognize early signs of anaphylaxis and alert the physician/team immediately. - Prepare epinephrine 0.3-0.5 mg 1:1000 IM without waiting for physician order if anaphylaxis is recognized (within scope of emergency nursing). - Administer epinephrine IM into the anterolateral thigh. - Ensure high-flow oxygen and airway equipment are available. - Establish IV access and administer fluids. - Monitor continuously. - Be alert for biphasic reactions during hospital stay. - Educate patient and family on allergen avoidance, auto-injector use, and warning signs before discharge. Critical NLE Pearls on Anaphylaxis: 1. **Epinephrine is first-line; it is given IM (not IV initially), 0.3-0.5 mg of 1:1000 concentration in the anterolateral thigh.** 2. **Antihistamines and corticosteroids are adjuncts—they do not replace epinephrine and are too slow for acute symptoms.** 3. **Airway obstruction from laryngeal edema is the leading cause of anaphylaxis death.** 4. **Biphasic reactions occur in 5-15% and can be severe; all anaphylaxis patients require hospital observation.** 5. **Common triggers: foods (peanuts, shellfish), medications (penicillin), insect venom, latex.** 6. **Epinephrine auto-injectors should be prescribed to all patients with anaphylaxis history and used for any suspected anaphylaxis.** 7. **After auto-injector use, patient must go to hospital even if symptoms improve.**

Latex allergy is an increasingly recognized problem in healthcare settings globally and in the Philippines. It can manifest as either type IV (delayed) contact dermatitis or type I (immediate) IgE-mediated allergy, with potential progression to anaphylaxis. Understanding latex allergy is essential for nurses because healthcare workers and latex-sensitive patients require special precautions. Sources and Routes of Exposure: Latex is derived from the milky sap of the rubber tree (Hevea brasiliensis) and is processed into products used extensively in healthcare: - Medical gloves (examination gloves, surgical gloves) - Catheters (Foley catheters, intermittent catheters, suprapubic catheters) - Endotracheal tubes and airway equipment - Anesthesia masks and breathing circuits - Blood pressure cuffs - Stethoscope tubing - Bandages and tape - IV catheters and infusion sets - Elastic bandages - Dental dams - Condoms Exposure occurs through direct skin contact (wearing latex gloves), inhalation (aerosolized latex particles from gloves, especially when gloves are donned/removed), and mucosal contact (e.g., latex catheter in bladder, latex dental dam in mouth). Two Forms of Latex Allergy: 1. **Type IV Delayed Contact Dermatitis (Most Common)** This is a cell-mediated hypersensitivity to the chemical additives used in latex processing (accelerators such as thiuram and carbamates, not to latex protein itself). Reactions develop 24-48 hours after exposure. Clinical Presentation: - Erythema (redness), itching, and eczematous dermatitis at the site of glove contact (typically hands, wrists) - Skin is dry, cracked, and may blister - Localized to contact area (hands if gloves worn) - Can progress to chronic hand dermatitis if exposure continues Management: - Avoid latex glove exposure; use non-latex gloves (nitrile, vinyl, synthetic polymers) - Wash hands thoroughly after latex exposure - Use fragrance-free moisturizers - Topical corticosteroids (hydrocortisone cream) if dermatitis is present - Type IV reaction is not anaphylactic; risk of severe systemic reaction is low 2. **Type I Immediate IgE-Mediated Allergy (Dangerous)** This is an IgE-mediated hypersensitivity to latex proteins (Hev b proteins), not the chemical additives. This is the dangerous form because it can progress to anaphylaxis. Clinical Presentation: Onset is within minutes of exposure. Manifestations include: - Localized: Urticaria (hives), pruritus (itching), and angioedema at contact sites - Respiratory: Rhinitis (sneezing, nasal congestion), asthma (wheezing, dyspnea), laryngeal edema, stridor - Ocular: Itchy, watery eyes, conjunctivitis - Systemic: Anaphylaxis with hypotension, shock, loss of consciousness (in severe cases) In healthcare settings, anaphylaxis from latex has been documented during procedures, particularly in patients undergoing surgery (sensitized from prior glove exposure). Atmospheric Latex Exposure: Powdered latex gloves, especially when donned or removed, release aerosolized latex particles that can be inhaled. This can cause respiratory symptoms (rhinitis, asthma) even without direct hand contact. This is why latex-sensitive individuals in healthcare settings risk reactions from ambient latex exposure. High-Risk Populations for Latex Allergy: 1. **Healthcare Workers**: Due to repeated daily latex glove exposure and inhalation of aerosolized latex. - Prevalence: 5-17% among healthcare workers (up to 10% or more in some studies) - Occupations at highest risk: surgeons, anesthesiologists, nurses, operating room staff, dental professionals - In the Philippines, healthcare worker latex allergy is underrecognized, but prevalence is likely similar to developed countries 2. **Patients with Spina Bifida and Other Neurogenic Bladder Conditions**: - These patients undergo repeated bladder catheterization (sometimes daily intermittent catheterization) from infancy or childhood onward - Prevalence of latex allergy in spina bifida: 40-60% (much higher than general population) - Early latex exposure during frequent procedures predisposes to sensitization - These patients must have all medical care and procedures in a latex-free environment 3. **Patients with Multiple Prior Surgeries**: - Repeated surgical exposure to latex gloves and equipment increases risk of sensitization 4. **Occupational Exposure**: - Rubber industry workers, hairdressers (latex gloves), custodial staff (latex gloves) 5. **Allergic Individuals**: - Those with atopy (genetic predisposition to allergies) have higher risk of latex allergy Latex-Fruit Syndrome (Cross-Reactivity): A well-documented phenomenon is cross-reactivity between latex proteins (Hev b) and proteins in certain tropical fruits. Patients with latex allergy may experience IgE-mediated reactions when handling or eating certain fruits: - **Banana** (highest risk; ~30-50% cross-reactivity in latex-allergic patients) - **Avocado** (20-40% cross-reactivity) - **Kiwi fruit** (20-40% cross-reactivity) - **Chestnut** (less common) Other fruits with reported but lower cross-reactivity: papaya, passion fruit, peach, apple, carrot, potato. The allergen proteins are heat-labile (destroyed by cooking), so cooked fruit is usually safe, but raw fruit is risky in latex-allergic individuals. Patients with latex allergy should be counseled to avoid raw banana, avocado, and kiwi. In the Philippines, where these tropical fruits are common and inexpensive, this cross-reactivity must be addressed in patient education. Diagnosis: 1. **Clinical History**: Ask about timing of symptoms relative to glove use, occupational exposure, symptoms with fruit handling. 2. **Skin Testing**: Latex-specific IgE skin testing can be done; wheal-and-flare reaction indicates sensitization. Must be performed by allergist with emergency equipment available. 3. **Serum-Specific IgE (RAST/ImmunoCAP)**: Tests for IgE antibodies to latex proteins or Hev b allergen components. 4. **Glove Use Test (In-Use Testing)**: Patient wears latex gloves and is observed for reaction (not ideal but sometimes used). Nursing Management and Prevention: 1. **Identify Latex-Sensitive Patients**: - Ask all patients on admission about latex allergy or symptoms with glove exposure - Include latex allergy in allergy assessment alongside drug and food allergies - Pay special attention to patients with spina bifida—assume latex allergy unless proven otherwise - Ask healthcare workers about symptoms (dermatitis, respiratory symptoms, systemic symptoms) with glove use 2. **Create a Latex-Free Environment**: - **Use non-latex gloves** (nitrile, vinyl, synthetic polymers) for all care of latex-sensitive patients - Ensure all equipment is latex-free: catheters, endotracheal tubes, tourniquets, bandages, tape, BP cuffs - Remove standard latex-containing equipment and replace with latex-free alternatives - This applies to ALL care (medical procedures, wound care, bathing, hygiene) and ALL settings (hospital, outpatient, home care) - Be aware that some "non-latex" products may still contain latex or latex-contaminated packaging; read labels carefully 3. **Operating Room Precautions for Latex-Sensitive Patients**: - Latex-sensitive patients should ideally be **scheduled as the first case of the day** - Why? Because at the start of the day, OR air has not been contaminated by aerosolized latex particles from earlier cases; first-case scheduling minimizes ambient latex exposure - All OR staff must wear non-latex gloves - All equipment must be latex-free (catheters, drapes, tapes, retractors) - Use latex-free anesthesia circuit, masks, and breathing tubes - Have epinephrine and emergency airway equipment immediately available in the OR - Use latex-free prep solutions and bandages - Communicate the latex allergy prominently (e.g., red flag on chart, verbal report in time-out) 4. **Education of Latex-Sensitive Patients**: - Inform patient of all products and foods to avoid - Educate on latex-free alternatives for personal use (condoms, dental care) - Provide a list of safe products and manufacturers - Counsel on latex-fruit cross-reactivity and avoidance of raw banana, avocado, kiwi - Advise to wear medical-alert bracelet identifying latex allergy - Inform family and caregivers to alert all healthcare providers of the allergy 5. **Education of Healthcare Workers with Latex Allergy**: - Inform of occupational accommodations: use non-latex gloves, ensure latex-free workspace - Discuss potential career implications if allergy is severe (may not be able to work in OR, delivery room) - Counsel on use of epinephrine auto-injector if history of anaphylaxis - Some occupational health services offer hyposensitization (immunotherapy) to latex, though this is not widely available 6. **Public Health and Institutional Policy**: - Many hospitals and clinics are moving to latex-free glove use for all patients (not just latex-sensitive) to eliminate ambient latex exposure - Some countries have mandated reduced-protein, powder-free latex gloves or latex-free alternatives as standard - In the Philippines, adoption of latex-free practices varies; resource constraints may limit widespread change, but advocacy for latex-free options, especially in ORs and for spina bifida patients, is important Nursing Diagnosis and Care Planning: For a patient with latex allergy, relevant NANDA diagnoses include: - **Risk for Anaphylaxis** (if type I allergy): related to exposure to latex-containing products - **Impaired Skin Integrity** (if type IV dermatitis): related to contact dermatitis from latex exposure - **Anxiety**: related to concern about allergic reactions and need for environmental modifications Interventions: 1. Create and maintain a latex-free environment 2. Use non-latex gloves 3. Keep epinephrine and airway equipment available (for type I allergy) 4. Educate patient on allergen avoidance and cross-reactivity 5. Communicate allergy status to all team members 6. Ensure post-operative observation for delayed-phase reactions (if surgery performed)

Immunodeficiency is a deficient immune response (either innate or adaptive) that leaves the person vulnerable to recurrent, persistent, opportunistic, or severe infections. The burden of immunodeficiency in the Philippines is significant, particularly due to malnutrition, HIV/AIDS, and limited access to vaccination in some areas. Understanding immunodeficiency is essential for nurses at all NCM levels to implement appropriate protective measures and patient education. Classification: Immunodefiencies are broadly classified as primary (congenital, present from birth) or secondary (acquired, resulting from another condition or treatment). PRIMARY (CONGENITAL) IMMUNODEFICIENCIES: These are inherited genetic defects affecting the immune system. They are rare but critical to recognize because management and counseling differ from acquired immunodeficiency. 1. **Severe Combined Immunodeficiency (SCID)** - The prototypical primary immunodeficiency affecting both B and T lymphocytes - Result of genetic mutations affecting lymphocyte development (various genes: IL2RG for X-linked SCID, ADA deficiency, RAG deficiency, etc.) - Profound deficiency of T cells, B cells, and NK (natural killer) cells - Presents in infancy (typically before 6 months) with recurrent, severe, opportunistic infections (Pneumocystis jirovecii pneumonia, cytomegalovirus, candidiasis) - Famous case: "David, the Bubble Boy" in the 1970s, a boy with X-linked SCID who required living in a sterile plastic bubble to prevent infection - Without treatment (bone marrow transplant, gene therapy, or enzyme replacement for ADA deficiency), SCID is lethal—most affected children die in infancy - Treatable only with hematopoietic stem cell transplant or gene therapy; supportive care includes protective isolation, prophylactic antibiotics and antifungals, and IVIG 2. **Selective IgA Deficiency** - Most common primary immunodeficiency (prevalence 1 in 300-500 in Caucasians, varies in other populations) - Complete or near-complete absence of IgA (serum IgA <7 mg/dL) - Because IgA protects mucosal surfaces (respiratory, GI tract), deficiency predisposes to mucosal infections (sinusitis, otitis media, recurrent respiratory infections) - Often asymptomatic, discovered incidentally - **Important consideration**: Patients with IgA deficiency are at risk for developing anti-IgA antibodies if they receive blood transfusions or IVIG (which contain IgA). If IgA-deficient patients require transfusion, IgA-depleted blood products should be used to avoid transfusion reactions 3. **Bruton Agammaglobulinemia (X-Linked Agammaglobulinemia)** - X-linked recessive disorder affecting male infants - Mutation in BTK gene (Bruton tyrosine kinase) prevents B-cell maturation - Result: absent or severely reduced B cells, very low immunoglobulin levels (all classes), normal T-cell function - Presents after 6 months of age (after maternal IgG protection wanes) with recurrent bacterial infections (streptococci, staphylococci, Haemophilus) - Treated with IVIG replacement (200-400 mg/kg monthly or more frequently) given IV or subcutaneously - With IVIG, life expectancy and quality of life significantly improve 4. **DiGeorge Syndrome (22q11 Deletion Syndrome)** - Microdeletion on chromosome 22q11 - Affects development of the thymus (T-cell production) and parathyroid glands - Variable presentation from complete DiGeorge (absent thymus, profound T-cell deficiency) to partial DiGeorge (reduced but not absent T-cell function) - Associated with cardiac defects, cleft palate, hypocalcemia (from hypoparathyroidism), and facial abnormalities - T-cell deficiency predisposes to viral, fungal, and protozoal infections - Some patients recover T-cell function spontaneously over time; others require long-term protective measures - Treatment is supportive; thymic transplant may be considered in severe cases 5. **Other Primary Immunodeficiencies** (less commonly tested for NLE but important to know exist): - Wiskott-Aldrich syndrome (X-linked; combines immunodeficiency with thrombocytopenia and eczema) - Ataxia-telangiectasia (autosomal recessive; affects T cells and antibody production, also causes neurologic symptoms) - Common variable immunodeficiency (CVID; primarily B-cell dysfunction, low antibody levels, variable severity) - Chronic granulomatous disease (phagocyte defect; recurrent infections with catalase-positive organisms; granuloma formation) - Complement deficiencies (rare; various manifestations depending on which complement component is deficient) SECONDARY (ACQUIRED) IMMUNODEFICIENCIES: These are far more common globally and are the result of another disease, condition, or treatment. 1. **HIV/AIDS (Human Immunodeficiency Virus / Acquired Immunodeficiency Syndrome)** - The most common and clinically significant secondary immunodeficiency worldwide - HIV destroys CD4+ T helper lymphocytes (also called CD4 T cells), the orchestrators of adaptive immunity - As CD4 count falls, both T-cell and B-cell functions decline - CDC classification (USA) and WHO staging (international) based on CD4 count and clinical events: - CD4 >500 cells/µL: minimal opportunistic infection risk - CD4 200-500 cells/µL: moderate risk (Pneumocystis jirovecii pneumonia prophylaxis recommended) - CD4 <200 cells/µL: high risk for PCP, toxoplasmosis, cryptococcosis - CD4 <50 cells/µL: risk of cytomegalovirus, Mycobacterium avium complex (MAC) - In the Philippines, HIV prevalence is lower than in some Asian countries, but cases are increasing, particularly in urban centers and among men who have sex with men (MSM). Nurses must be aware of HIV risk and transmission prevention - Treatment: Antiretroviral therapy (ART) with combination drugs (HAART—highly active antiretroviral therapy) can suppress viral replication, allow CD4 recovery, prevent opportunistic infections, and extend lifespan dramatically - Prevention: Pre-exposure prophylaxis (PrEP), post-exposure prophylaxis (PEP), safe sexual practices, needle/syringe programs for injection drug users - Nursing role: Educate on ART adherence, infection prevention, safe practices, and psychological support; manage opportunistic infections; advocate for HIV-positive patients 2. **Malignancy (Cancer)** - Leukemia and lymphoma directly impair immune function: - Leukemia (overproduction of abnormal WBCs) crowds out normal immune cells - Lymphoma (cancer of lymphocytes) destroys lymphoid tissue - Other cancers impair immunity indirectly through metabolic effects and tumor burden - Immunodeficiency increases infection risk 3. **Chemotherapy and Radiation Therapy** - Both destroy rapidly dividing cells, including bone marrow cells and lymphocytes - Result: neutropenia (low neutrophil count), lymphopenia (low lymphocyte count), thrombocytopenia (low platelets) - Immunodeficiency is reversible if chemotherapy is discontinued and bone marrow recovers - During treatment, protective measures are critical 4. **Immunosuppressive Medications** - Corticosteroids (prednisone, dexamethasone): suppress T-cell and B-cell function; long-term use causes significant immunosuppression - Calcineurin inhibitors (cyclosporine, tacrolimus): used for transplant rejection prevention; suppress T-cell activation - Tumor necrosis factor-alpha (TNF-α) inhibitors (infliximab, etanercept, adalimumab): used for rheumatoid arthritis, inflammatory bowel disease, etc.; suppress cell-mediated immunity; associated with reactivation of latent tuberculosis - Other agents: mycophenolate, azathioprine, methotrexate - Immunodeficiency is reversible if the drug is discontinued, but duration is variable 5. **Malnutrition** - Particularly in developing countries, including the Philippines - Protein-calorie malnutrition impairs T-cell function, B-cell antibody production, and complement - Micronutrient deficiencies (zinc, iron, vitamins A, C, E) further impair immunity - Kwashiorkor and marasmus in children cause severe immunodeficiency - Treatable with nutritional rehabilitation 6. **Splenectomy (Surgical Removal of the Spleen)** - The spleen removes encapsulated bacteria (pneumococci, meningococci, Haemophilus influenzae) via the alternative complement pathway - Splenectomy (for trauma, hemolytic anemia, thrombocytopenia, etc.) increases risk of overwhelming post-splenectomy infection (OPSI), often with septic shock and death - Asplenic patients should receive: pneumococcal vaccine (Pneumovax 23), meningococcal vaccine, Haemophilus influenzae type B vaccine (if not previously given), and annual influenza vaccine - Prophylactic antibiotics (penicillin V) are debated; some recommend long-term prophylaxis - In the Philippines, trauma is a leading cause of splenectomy; post-splenectomy infection prevention education is important 7. **Aging** - Physiologic immunosenescence occurs with advancing age - T-cell function declines, antibody response to vaccination decreases, innate immune responses diminish - Result: increased infection risk, vaccine effectiveness decreases, delayed recovery from illness - Influenza and pneumonia are leading causes of death in elderly - Geriatric population requires careful infection prevention and appropriate vaccination 8. **Other Secondary Causes**: - Chronic kidney disease (loss of immunoglobulin in urine, uremia impairs immune function) - Chronic liver disease (decreased complement and antibody synthesis) - Diabetes mellitus (impaired neutrophil and T-cell function, hyperglycemia favors infection) - Hyposplenism/asplenia (from functional asplenia in sickle cell disease, celiac disease) Clinical Presentation of Immunodeficiency: - Recurrent infections (more frequent than normal for age/population) - Persistent infections (infections that do not clear despite appropriate treatment) - Severe infections (requiring hospitalization, sepsis) - Opportunistic infections (unusual organisms that rarely cause disease in immunocompetent hosts: Pneumocystis jirovecii, Cytomegalovirus, Candida, Mycobacterium avium complex, Cryptococcus) - Infections with atypical presentations or in atypical sites - Recurrent infections with the same organism (indicates specific immune defect) - Poor response to vaccines Nursing Management of Immunodeficiency: 1. **Protective (Neutropenic) Precautions** for patients with severe immunosuppression (CD4 <200, neutrophil count <500, chemotherapy-induced immunodeficiency): - **Hand Hygiene**: Meticulous hand washing before patient contact; teach patient to wash hands frequently - **Private Room**: Single room with closed door to reduce ambient pathogens - **Visitor Screening**: Restrict visitors with signs of infection; limit number of visitors - **Avoid Crowds**: No crowded areas; limited group activities - **Avoid Exposure to Infection**: No visits from people with active infection; no fresh flowers, standing water (breeding grounds for mold), or plants (soil contains fungi) - **Diet**: No raw or undercooked foods (risk of foodborne pathogens); thoroughly cooked foods, pasteurized dairy, bottled drinks, washed fruits/vegetables - **Hygiene**: Daily bathing, perirectal care, mouth care (rinse with antimicrobial solution if prescribed) - **Environmental Cleaning**: Regular cleaning of room and surfaces - **Mask Use**: Patient may wear a mask when outside the room to reduce inhalation of pathogens; healthcare workers wear masks if they have respiratory symptoms 2. **Infection Monitoring and Early Detection**: - **Fever is the Key Sign**: In severely immunocompromised patients, fever may be the only sign of serious infection. Treat ALL fever (even low-grade) as infection until proven otherwise - Monitor vital signs at least every 4 hours; more frequently if fever develops - Obtain blood cultures, urinalysis and culture, sputum culture, chest X-ray, and other diagnostics per protocol at first sign of fever - Report fever >38.5°C (101.3°F) or ANY fever in high-risk patients immediately to physician - Do not delay antibiotics; empiric broad-spectrum antibiotics are started immediately (often before culture results) - Assess for subtle signs of infection: localized pain, erythema, discharge, diarrhea, cough, dyspnea, mental status changes 3. **Vaccination**: - **Live Vaccines Are Generally Contraindicated** in significant immunodeficiency (CD4 <200, neutrophil <500, active chemotherapy) because live virus can cause disseminated vaccine-strain disease - Live vaccines include: varicella (chickenpox), MMR (measles, mumps, rubella), rotavirus, yellow fever, some influenza formulations (live attenuated influenza vaccine—LAIV), BCG (Bacille Calmette-Guérin), and others - Inactivated/killed vaccines are safer in immunodeficiency: polio (IPV), hepatitis B, hepatitis A, influenza (inactivated), pneumococcal (Pneumovax 23, Prevnar 13), meningococcal, Haemophilus influenzae type B - **Timing of Vaccination**: If possible, vaccinate BEFORE immunosuppression occurs (e.g., before chemotherapy) when immune response is intact. If immunosuppressed, delay live vaccines until CD4 recovers (usually ≥200 for ≥3 months after ART initiation in HIV patients) - In the Philippines, the EPI includes both live and inactivated vaccines; nurses must know which are safe for each patient's immunodeficiency status 4. **Antimicrobial Prophylaxis**: - **Pneumocystis jirovecii pneumonia (PCP) prophylaxis**: Trimethoprim-sulfamethoxazole (TMP-SMX) or alternatives for CD4 <200 (HIV patients) - **Toxoplasmosis prophylaxis**: TMP-SMX for CD4 <100 and toxoplasmosis serology positive - **Mycobacterium avium complex (MAC) prophylaxis**: Azithromycin for CD4 <50 - **Tuberculosis prophylaxis**: Isoniazid (INH) for tuberculin-positive patients with CD4 >200 - **Fungal prophylaxis**: Fluconazole for recurrent candidiasis - Prophylaxis regimens vary; follow institutional protocols 5. **Immunoglobulin Replacement (IVIG)**: - For antibody deficiencies (Bruton agammaglobulinemia, common variable immunodeficiency, SCID with B-cell deficiency) - IVIG is given IV or subcutaneously at regular intervals (typically monthly or every 3-4 weeks for IV; weekly for subcutaneous) - Dose is typically 200-600 mg/kg per infusion, adjusted based on trough IgG levels - Nursing considerations for IVIG infusion: - Start slowly (0.5 mL/min for first 15 minutes); increase gradually to 1.5-2 mL/min if tolerated - Monitor for infusion reactions: chills, fever, myalgia, headache, back pain (often occur with rapid infusion) - Have epinephrine and antihistamines available (rare anaphylaxis possible, especially in IgA-deficient patients) - Premedication with acetaminophen and diphenhydramine reduces reactions - After infusion, continue observation for delayed reactions 6. **Patient and Family Education**: - Explain the immunodeficiency and why infections are a risk - Teach hand hygiene, food safety, and infection prevention - Educate on signs of infection and when to seek medical care (fever, cough, diarrhea, etc.) - Teach medication compliance (ART for HIV, prophylactic antibiotics, etc.) - Discuss safe sexual practices and prevention of transmission (if applicable) - Inform about vaccine safety and timing - Provide emotional and psychosocial support; immunodeficiency can be isolating and emotionally challenging - Connect with support groups and resources Nursing Diagnoses for Immunodeficiency: Common NANDA diagnoses include: - **Risk for Infection**: related to immunodeficiency from (disease/treatment) - **Knowledge Deficit**: related to infection prevention and medication management - **Social Isolation**: related to need for protective precautions and infectiousness concerns (if applicable) - **Anxiety**: related to chronic illness and infection risk - **Ineffective Coping**: related to burden of disease Comparison: Primary vs. Secondary Immunodeficiency (Table for NLE): | Feature | Primary | Secondary | |---------|---------|----------| | **Onset** | Present from birth / infancy | Develops later in life | | **Cause** | Genetic mutation; inherited | External factor (disease, drug, malnutrition) | | **Examples** | SCID, IgA deficiency, DiGeorge | HIV/AIDS, chemotherapy, malnutrition | | **Frequency** | Rare | Common | | **Reversibility** | Usually not reversible; lifelong | Often reversible if cause is removed | | **Family History** | Often positive | Typically negative | | **Treatment** | IVIG, transplant, gene therapy | Treat underlying cause | | **NLE Emphasis** | Know SCID, IgA deficiency, Bruton | Know HIV/AIDS, know protective measures | Key Philippine Context: The Philippines faces significant immunodeficiency challenges: - **Malnutrition**: Still prevalent in poor and rural areas; affects immune function in children and adults - **Infectious Diseases**: Tuberculosis, dengue, and other endemic infections are common; patients with immunodeficiency are at higher risk - **HIV/AIDS**: Case numbers are increasing, particularly in urban areas and among MSM; stigma and limited resources challenge management - **Limited Access to Vaccines and Protective Measures**: In some rural and remote areas, protective isolation and IVIG may be unavailable - **Healthcare Worker Training**: Nurses in all settings must understand immunodeficiency to provide appropriate care In NCM Level 2 (Community Health Nursing), nurses assess nutritional status and promote adequate nutrition, educate on infection prevention, and identify at-risk individuals. In NCM Level 3 (Hospital Nursing), nurses implement protective precautions, manage infections, and educate hospitalized immunodeficient patients.