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NLE Endocrine & Metabolic Nursing — Pituitary, Thyroid & Parathyroid DisordersCheat Sheet

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Pituitary, Thyroid & Parathyroid Disorders cheat sheet — the reference card you wish you had on exam day. Condensed from the full study notes, this is the high-yield core of Pituitary, Thyroid & Parathyroid Disorders for NLE Endocrine & Metabolic Nursing. Download, print, revise.

Exam context

For the Philippine Nurse Licensure Examination (PNLE), Professional Regulation Commission (PRC) — Board of Nursing tests Endocrine & Metabolic Nursing under a "Core" label, with Pituitary, Thyroid & Parathyroid Disorders in the 1st slot across 3 chapters. NLE candidates must clear the 75% weighted average with no sub-test below 60% cut on the 2026 paper, which draws about 50 Endocrine & Metabolic Nursing questions. Date to watch: Bi-annual.

Pituitary, Thyroid & Parathyroid Disorders - Cheat Sheet

Your last-minute revision companion for endocrine crisis management, hormone axis dysfunction, and exam-critical nursing interventions. Master the paired opposites (too much vs. too little), the two life-threatening crises, and the must-know labs and treatments.

Sections

Common Values

Value

135–145 mEq/L

Symbol

Na+

Quantity

Normal serum sodium

Value

280–295 mOsm/kg

Symbol

Posm

Quantity

Normal serum osmolality

Value

1.005–1.030

Symbol

USG

Quantity

Normal urine specific gravity

Value

<120 mEq/L

Symbol

Na+

Quantity

SIADH hyponatremia threshold (symptomatic)

Section Title

Posterior Pituitary: ADH Disorders

Important Facts

ADH RETENTION: **S**IADH = **S**oaked (retains water, low sodium, restrict fluids)
ADH LOSS: DI = Dry (loses water, high sodium, replace fluids + DDAVP)
SIADH labs: LOW serum sodium, LOW osmolality; HIGH urine sodium & osmolality
DI labs: HIGH serum sodium & osmolality; LOW urine osmolality & specific gravity
SIADH cornerstone: FLUID RESTRICTION (even when thirsty); hypertonic saline (3%) only for severe/symptomatic hyponatremia
CORRECT sodium SLOWLY in SIADH (≤8–10 mEq/L per 24 hrs) to avoid osmotic demyelination syndrome
DI management: replace fluids + central DI → desmopressin (DDAVP) synthetic ADH; nephrogenic → high fluid intake + NSAIDs/thiazides
SIADH triggers: malignancy (especially SCLC), CNS disorders (meningitis, head trauma, seizures), pulmonary disease, surgery, drugs (carbamazepine, SSRIs, vincristine)
DI post-op risk: highest after pituitary surgery; monitor output/specific gravity closely
Seizure precautions for SIADH (severe hyponatremia <120 mEq/L causes cerebral edema)

Key Definitions

Term

Antidiuretic Hormone (ADH/Vasopressin)

Example

Normal ADH levels → kidneys concentrate urine (high specific gravity) and retain water

Definition

Posterior pituitary hormone that promotes kidney water reabsorption to conserve body water and maintain osmolality.

Term

SIADH (Syndrome of Inappropriate ADH)

Example

Small-cell lung cancer patient with low sodium (125 mEq/L) and concentrated urine despite hypo-osmolal state

Definition

Excessive ADH secretion causing water retention, dilutional hyponatremia, and concentrated urine despite low serum osmolality.

Term

Diabetes Insipidus (DI)

Example

Post-hypophysectomy patient losing 15 L/day of dilute urine with urine specific gravity of 1.002

Definition

Deficiency of ADH (central) or renal unresponsiveness (nephrogenic) causing massive dilute polyuria and hypernatremia risk.

Diagrams To Know

ADH feedback loop: osmolality/volume change → posterior pituitary → ADH release → kidney aquaporin channels → water reabsorption
SIADH vs DI comparison chart (H2O retention vs loss, sodium direction, urine vs serum osmolality)

Common Values

Value

0.8–1.8 ng/dL

Symbol

FT4

Quantity

Normal Free T4

Value

2.3–4.2 pg/mL

Symbol

FT3

Quantity

Normal Free T3

Value

0.5–5.0 mIU/L (varies by lab)

Symbol

TSH

Quantity

Normal TSH

Value

>39.5–40°C (often 40–41°C hyperpyrexia)

Symbol

T°

Quantity

Thyroid storm temperature threshold

Section Title

Thyroid Disorders: Hyperthyroidism & Thyroid Storm

Important Facts

Hyperthyroidism labs: ↑T3, ↑T4, ↓TSH (in primary disease); radioiodine uptake elevated
Hyperthyroid signs: weight LOSS despite ↑appetite, heat intolerance, diaphoresis, tachycardia/palpitations/AFib, hypertension, tremor, insomnia, diarrhea, warm moist skin, nervousness
Graves'-specific: exophthalmos (bulging eyes—autoimmune) + goiter; occurs in both eyes (infiltrative ophthalmopathy)
Antithyroid drugs (methimazole & PTU): block hormone synthesis; effects take 4–8 weeks; must TEACH TO REPORT sore throat/fever (agranulocytosis = bone-marrow suppression)
PTU preferred in FIRST TRIMESTER pregnancy (crosses placenta less than methimazole; methimazole teratogenic—aplasia cutis)
Beta-blockers (propranolol): DO NOT treat the underlying disease, only symptom relief (tachycardia, tremor, anxiety); effect is rapid
Iodine (Lugol's solution, SSKI): GIVE AFTER antithyroid drugs (NOT before); reduces gland vascularity/hormone release within 24–48 hrs; **DILUTE in juice, give through STRAW** (stains teeth); brief effect only
Radioactive iodine (I-131): ablates thyroid → permanent hypothyroidism in most patients (need lifelong levothyroxine); avoid pregnancy for 6 months post-treatment
Thyroidectomy: most definitive cure; keep **tracheostomy set, O2, suction at bedside** (airway emergency); support neck; check **behind neck for hemorrhage** (not just front of dressing)
Post-thyroidectomy complications: hemorrhage (most common early), laryngeal nerve damage (hoarseness = recurrent laryngeal nerve injury), hypocalcemia/tetany (parathyroid damage)

Key Definitions

Term

Thyroid Hormone (T3 & T4)

Example

Excess T4/T3 = tachycardia, weight loss, heat intolerance (metabolism speeds up)

Definition

Metabolic hormones produced by thyroid follicles; set basal metabolic rate; require iodine.

Term

TSH (Thyroid-Stimulating Hormone)

Example

Graves' disease: LOW TSH + HIGH free T4 (feedback loop shows gland is overactive)

Definition

Anterior pituitary hormone driving thyroid secretion; inverse feedback (low TSH = high T3/T4 in primary hyperthyroidism).

Term

Graves' Disease

Example

Exophthalmos + goiter + tachycardia + heat intolerance = classic Graves' presentation

Definition

Autoimmune hyperthyroidism; TSH-receptor antibodies stimulate thyroid; most common cause of hyperthyroidism.

Term

Thyroid Storm (Thyrotoxic Crisis)

Example

Poorly controlled hyperthyroid patient post-op: fever 41°C, HR 160, delirium → requires emergency intervention

Definition

Life-threatening exacerbation of hyperthyroidism with uncontrolled hormone release; triggered by infection, surgery, stress, or iodine exposure.

Diagrams To Know

HPG axis: hypothalamus (TRH) → anterior pituitary (TSH) → thyroid (T3/T4); negative feedback (high T3/T4 suppresses TRH & TSH)
Post-thyroidectomy assessment sequence: airway patency → hemorrhage → voice/nerve function → hypocalcemia signs (Chvostek/Trousseau)

Reactions Or Equations

Note

This is why thyroid storm is a medical emergency—uncontrolled metabolic overdrive

Equation

Thyroid hormone effects: ↑T3/T4 → ↑metabolic rate, ↑heat production, ↑O2 consumption, ↑cardiovascular workload

Conditions

Acute hyperthyroidism or thyroid storm

Common Values

Value

25–50 mcg once daily (elderly/cardiac: start ~25 mcg)

Symbol

Synthroid

Quantity

Levothyroxine initial dose (adult)

Value

75–150 mcg once daily

Symbol

Synthroid

Quantity

Levothyroxine typical maintenance

Value

<32°C (profound hypothermia)

Symbol

T°

Quantity

Myxedema coma core temperature threshold

Section Title

Thyroid Disorders: Hypothyroidism & Myxedema Coma

Important Facts

Hypothyroidism labs: ↓T3, ↓T4, ↑TSH (in primary disease); indicates gland failure with compensatory ↑TSH from pituitary
Hypothyroid signs: weight GAIN, cold intolerance, fatigue/lethargy, bradycardia, constipation, dry coarse skin/hair, hair loss, depression, slowed cognition, myxedema (non-pitting facial/periorbital edema)
Levothyroxine (synthetic T4): ORAL on EMPTY stomach, 30–60 min BEFORE breakfast, same time daily; DO NOT take with calcium, iron, antacids (block absorption)
Levothyroxine dosing: START LOW & GO SLOW in elderly/cardiac patients (excess T4 increases myocardial O2 demand → angina/arrhythmia); usual adult ~100 mcg/day initially
Levothyroxine effect: gradual (takes weeks to reach steady state); NEVER stop abruptly (risk of relapse/coma)
Over-replacement signs: hyperthyroid symptoms (tachycardia, tremor, heat intolerance, palpitations, weight loss) → reduce dose
Under-replacement signs: persistent fatigue, cold intolerance, weight gain, bradycardia → increase dose
Myxedema coma triggers: cold exposure, infection, sedatives, abrupt levothyroxine discontinuation, severe untreated hypothyroidism
Myxedema coma management: **IV levothyroxine** (loading dose ~200–500 mcg IV, then lower maintenance doses), airway/ventilation support, WARM GRADUALLY (passive warming—active causes vasodilation/shock), IV glucose (hypoglycemia risk), IV fluids, corticosteroids (because of adrenal insufficiency often present)

Key Definitions

Term

Hypothyroidism

Example

Patient on levothyroxine post-radioactive iodine therapy; requires lifelong replacement

Definition

Insufficient thyroid hormone; slows metabolism; most commonly from Hashimoto's thyroiditis (autoimmune) or post-ablation.

Term

Myxedema

Example

Puffy, doughy facial appearance + coarse dry skin in severe chronic hypothyroidism

Definition

Non-pitting edema in hypothyroidism caused by glycosaminoglycan/fluid accumulation in subcutaneous tissue (face, periorbital).

Term

Myxedema Coma (Myxedema Crisis)

Example

Elderly patient found unresponsive in cold environment; temperature 32°C, BP 80/50, respiratory depression → requires emergency IV levothyroxine

Definition

Life-threatening decompensated hypothyroidism with hypothermia, hypotension, hypoglycemia, hypoventilation, and decreased consciousness.

Diagrams To Know

Levothyroxine absorption pathway: empty stomach → rapid GI absorption → peripheral conversion T4 → T3 (active form)
Myxedema coma cascade: untreated hypothyroidism → decompensation → hypothermia + hypotension + respiratory depression → coma

Reactions Or Equations

Note

Severe hypothermia + profound bradycardia + hypotension can mimic death; continue resuscitation in myxedema coma

Equation

Hypothyroid metabolic effects: ↓T3/T4 → ↓metabolic rate, ↓heat production, ↓O2 consumption, ↓cardiovascular workload → bradycardia, hypotension

Conditions

Chronic hypothyroidism or myxedema coma

Common Values

Value

8.5–10.5 mg/dL

Symbol

Quantity

Normal total serum calcium

Value

4.5–5.5 mg/dL (physiologically active)

Symbol

Ca2+

Quantity

Normal ionized calcium

Value

2.5–4.5 mg/dL

Symbol

PO4

Quantity

Normal serum phosphate

Value

10–65 pg/mL (lab-dependent)

Symbol

PTH

Quantity

Normal PTH

Value

<7 mg/dL

Symbol

Quantity

Severe hypocalcemia (symptomatic)

Section Title

Parathyroid Disorders: PTH, Calcium & Phosphate

Important Facts

Normal serum calcium: 8.5–10.5 mg/dL (ionized Ca 4.5–5.5 mg/dL is physiologically active)
Calcium & phosphate MOVE OPPOSITE: ↑PTH → ↑Ca, ↓phosphate; ↓PTH → ↓Ca, ↑phosphate
Normal phosphate: 2.5–4.5 mg/dL
Hyperparathyroidism presentation (BONES, STONES, GROANS, MOANS): bone pain/osteoporosis/fractures, kidney stones (hypercalciuria), GI upset (constipation/ulcers/pancreatitis), psychiatric symptoms (mood changes, anxiety, depression)
Hyperparathyroidism management: **hydration (IV normal saline) + loop diuretics (furosemide)** to promote urinary calcium loss (NOT thiazides—they retain calcium); bisphosphonates/calcitonin; **parathyroidectomy** (definitive); monitor for hypocalcemia post-op
Hypoparathyroidism labs: LOW PTH, LOW calcium, HIGH phosphate
Hypoparathyroidism acute: **TETANY—neuromuscular hyperexcitability** from hypocalcemia; **POSITIVE CHVOSTEK'S** (facial twitch on cheek tap), **POSITIVE TROUSSEAU'S** (carpal spasm with BP cuff), numbness/tingling (perioral, fingers), muscle cramps, laryngospasm (airway emergency), seizures
Hypoparathyroidism management: acute tetany → **IV calcium gluconate stat** (have ready after any neck surgery); chronic → oral calcium + active vitamin D (calcitriol); high-calcium low-phosphate diet; seizure/airway precautions
Post-thyroidectomy/parathyroidectomy: assess voice (laryngeal nerve), check for tremor/numbness (hypocalcemia), monitor serum calcium levels
Hypercalcemic crisis: polyuria/dehydration, cardiac arrhythmias (shortened QT), altered mental status, renal failure

Key Definitions

Term

Parathyroid Hormone (PTH)

Example

↑PTH → pulls calcium from bone + increases GI/renal calcium retention → serum Ca rises

Definition

Hormone from parathyroid glands that RAISES serum calcium by increasing bone resorption, GI absorption, and renal reabsorption; LOWERS phosphate.

Term

Hyperparathyroidism

Example

Post-menopausal woman: high PTH + high calcium + kidney stones + bone pain

Definition

Excess PTH causing hypercalcemia and hypophosphatemia; primary (parathyroid adenoma/hyperplasia), secondary (renal disease), or tertiary.

Term

Hypoparathyroidism

Example

Post-thyroidectomy patient: low calcium + high phosphate + positive Chvostek/Trousseau signs + tetany

Definition

Deficient PTH (often post-neck surgery) causing hypocalcemia and hyperphosphatemia; manifests as neuromuscular hyperexcitability/tetany.

Diagrams To Know

PTH effect on calcium & phosphate: ↑PTH → bone resorption + GI Ca absorption + renal Ca reabsorption + phosphate excretion
Chvostek's sign technique: tap facial nerve anterior to ear → facial muscles twitch (positive = hypocalcemia)
Trousseau's sign technique: inflate BP cuff above systolic for 3 min → wrist/hand carpal spasm (positive = hypocalcemia)

Reactions Or Equations

Note

This feedback is sensitive and fast; disruption causes acute symptoms

Equation

PTH axis: ↓serum Ca → parathyroid chief cells → ↑PTH release → kidney/bone/gut absorption ↑Ca, ↓phosphate → serum Ca normalized (negative feedback)

Conditions

Normal calcium homeostasis

Common Values

Value

5–20 mg TID (or divided doses up to 60 mg/day)

Symbol

Tapazole

Quantity

Methimazole dose (adult)

Value

100–150 mg TID

Symbol

Propyl-thyracil

Quantity

PTU dose (adult)

Value

10–40 mg QID

Symbol

Inderal

Quantity

Propranolol dose (hyperthyroidism)

Value

5–10 mcg BID (individualized)

Symbol

Stimate/DDAVP

Quantity

DDAVP intranasal typical dose

Section Title

Nursing Pharmacology: Key Drugs

Important Facts

Antithyroid drugs (methimazole/PTU): **TEACH PATIENT TO REPORT sore throat, fever, unusual bruising/bleeding** (agranulocytosis = life-threatening bone-marrow suppression)
PTU vs Methimazole: PTU preferred in FIRST TRIMESTER (methimazole teratogenic); methimazole after first trimester (easier dosing, fewer doses)
Iodine (Lugol's, SSKI): **GIVE AFTER starting antithyroid drugs** (not before—iodine alone can worsen hyperthyroidism); **DILUTE, GIVE THROUGH STRAW** (stains teeth); effect within 24–48 hrs (brief—days to weeks)
Radioactive iodine (I-131): causes hypothyroidism in 60–80% of patients within first year → lifelong levothyroxine needed
DDAVP watch: **AVOID over-replacement** (can cause water intoxication/SIADH/hyponatremia); teach patient signs (headache, drowsiness, nausea, weight gain)
Levothyroxine must-knows: **TAKE ON EMPTY STOMACH** (food impairs absorption); **NEVER STOP ABRUPTLY** (risk of relapse/myxedema coma); drug interactions (calcium, iron, antacids, phenytoin decrease absorption)
Levothyroxine dosing adjustment: recheck TSH 4–6 weeks after dose change (long half-life ~7 days, takes weeks for steady state)

Key Definitions

Term

Methimazole

Example

Patient with Graves' disease: start ~10 mg TID, monitor CBC for sore throat/fever

Definition

Antithyroid drug blocking thyroid hormone synthesis; effect in 4–8 weeks; preferred post–first trimester; agranulocytosis risk.

Term

Propylthiouracil (PTU)

Example

Pregnant patient with hyperthyroidism: PTU ~100 mg TID (safer than methimazole in trimester 1)

Definition

Antithyroid drug blocking synthesis + peripheral T4→T3 conversion; preferred in first trimester pregnancy; agranulocytosis risk.

Term

Propranolol (Beta-blocker)

Example

Graves' patient: propranolol 40 mg QID for rapid symptom relief while awaiting antithyroid drug effect

Definition

Non-selective beta-blocker; controls tachycardia, tremor, palpitations in hyperthyroidism; also inhibits T4→T3 peripheral conversion.

Term

Desmopressin (DDAVP)

Example

DI patient: DDAVP 10 mcg intranasal BID (can be titrated; watch for water intoxication/hyponatremia)

Definition

Synthetic ADH (vasopressin analog); used in central diabetes insipidus; intranasal or SC administration.

Term

Levothyroxine (Synthroid)

Example

Hypothyroid patient: levothyroxine 100 mcg PO once daily on empty stomach, 30 min before breakfast

Definition

Synthetic T4; lifelong replacement in hypothyroidism; oral on empty stomach; slow-acting (weeks to steady state).

Term

Calcium Gluconate

Example

Post-thyroidectomy tetany: IV calcium gluconate 10 mL of 10% solution in 50 mL saline over 2–5 min (have ready at bedside)

Definition

IV calcium replacement for acute symptomatic hypocalcemia/tetany; do NOT give IM (tissue necrosis).

Diagrams To Know

Antithyroid drug mechanism: blocks thyroid peroxidase → inhibits T3/T4 synthesis
Beta-blocker mechanism in hyperthyroidism: blocks beta-1 (tachycardia), beta-2 (tremor), + inhibits T4→T3 conversion

Section Title

Nursing Assessment & Post-Op Priorities

Important Facts

POST-THYROIDECTOMY AIRWAY PRIORITY: **keep tracheostomy set, O2, suction AT BEDSIDE** (highest risk early post-op)
POST-THYROIDECTOMY POSITIONING: **semi-Fowler's to upright**; support head/neck with pillows (prevents tension on suture line)
POST-THYROIDECTOMY HEMORRHAGE CHECK: inspect **BEHIND the neck/under dressing** (blood drains posteriorly, not visible from front); gentle palpation; report any oozing/swelling immediately
POST-THYROIDECTOMY VOICE ASSESSMENT: **check voice every 2–4 hrs initially**; hoarseness = recurrent laryngeal nerve injury; permanent vs temporary depends on nerve injury severity
POST-THYROIDECTOMY HYPOCALCEMIA: **assess for Chvostek's and Trousseau's signs** within 24–72 hrs; **tingling, numbness, muscle cramps** = early signs; **HAVE IV CALCIUM GLUCONATE READY**
POST-THYROIDECTOMY DIET: start soft/cool (throat pain); advance as tolerated; report dysphagia (nerve damage) or difficulty breathing
POST-PARATHYROIDECTOMY: **monitor serum calcium closely** (may drop acutely if hypoparathyroidism develops); have calcium gluconate ready; assess for tetany
SIADH nursing: **meticulous I&O, daily weight, strict fluid restriction**, even if patient complains of thirst; **monitor for hyponatremia signs** (confusion, headache, seizures); neuro checks Q1–2H if severe
DI nursing: **open access to water** (patient may be desperately thirsty); **monitor I&O/specific gravity**; teach patient to report signs of DDAVP over-replacement (headache, drowsiness, nausea, weight gain = water intoxication)
Thyroid storm nursing: **continuous cardiac monitoring** (watch for AFib, arrhythmias); **cooling measures** (tepid sponging, cool IV fluids, fans—NOT ice packs); **no aspirin** (displaces thyroid hormone); monitor temp Q15 min

Key Definitions

Term

Chvostek's Sign

Example

Post-thyroidectomy patient: tapping cheek → mouth twitch appears → hypocalcemia suspected

Definition

Tap the facial nerve anterior to the ear; positive = facial muscle twitch; indicates neuromuscular hyperexcitability from hypocalcemia.

Term

Trousseau's Sign

Example

Inflate cuff on arm to 200 mmHg for 3 min → wrist/hand goes into spasm → hypocalcemia confirmed

Definition

Inflate BP cuff above systolic for 3 minutes; positive = carpal spasm (thumb adduction, finger flexion); indicates hypocalcemia.

Diagrams To Know

Post-thyroidectomy hourly assessment sequence: airway → voice → neck (hemorrhage) → swallowing/throat → hypocalcemia signs
Calcium gluconate IV administration safety: **NEVER IM** (tissue necrosis); use **central line preferred** (peripheral OK but risk of phlebitis); **never add to bicarbonate** (precipitates)

Must Remember

**SIADH = SOAKED** (excess ADH → water retention, LOW sodium, concentrated urine, restrict fluids). **DI = DRY** (deficiency ADH → massive polyuria, HIGH sodium, replace fluids + DDAVP). Opposite problems → opposite management.
**ADH-axis labs are CRITICAL**: SIADH shows LOW serum sodium + LOW osmolality with HIGH urine osmolality (inappropriate for serum osmolality). DI shows HIGH serum sodium + HIGH osmolality with LOW urine osmolality. Know which is which or you fail the question.
**Thyroid storm (fever, severe tachycardia, agitation, delirium) = MEDICAL EMERGENCY**. Management: cooling (NOT aspirin—displaces hormone), propranolol, PTU, iodine, steroids, continuous monitoring. **Myxedema coma (hypothermia, hypotension, respiratory depression) = MEDICAL EMERGENCY**. Management: IV levothyroxine, airway support, warm gradually (passive—NOT active vasodilation), glucose, steroids.
**Post-thyroidectomy airway is #1 priority**: keep tracheostomy set/O2/suction AT BEDSIDE. Check for hemorrhage BEHIND the neck (not just front). Watch for hoarseness (laryngeal nerve damage) and hypocalcemia/tetany (parathyroid damage—Chvostek's/Trousseau's signs positive). Have calcium gluconate ready.
**Levothyroxine (Synthroid) MUST BE TAKEN**: on EMPTY stomach, 30–60 min BEFORE breakfast, same time daily, NEVER stop abruptly (relapse/coma risk). Start LOW & GO SLOW in elderly/cardiac (excess T4 = ↑myocardial O2 demand → angina/arrhythmia). Drug interactions: calcium, iron, antacids impair absorption.
**Antithyroid drugs (methimazole/PTU)**: effect takes 4–8 weeks (NOT rapid). TEACH PATIENT TO REPORT sore throat, fever, unusual bruising = agranulocytosis (bone-marrow suppression). PTU preferred in FIRST TRIMESTER pregnancy; methimazole after. Iodine (Lugol's/SSKI) MUST BE GIVEN AFTER antithyroid drugs started (not before), diluted, through straw, effect within 24–48 hrs.
**PTH RAISES calcium; calcium & phosphate move OPPOSITE**: ↑PTH → ↑Ca + ↓phosphate. ↓PTH → ↓Ca + ↑phosphate. Hyperparathyroidism = high Ca (BONES-STONES-GROANS-MOANS: fractures, stones, GI upset, psychiatric). Hypoparathyroidism = low Ca (TETANY: numbness, Chvostek's/Trousseau's, laryngospasm—airway emergency).
**Hypocalcemia signs (hypoparathyroidism/post-thyroidectomy)**: tingling (perioral, fingers), muscle cramps, positive CHVOSTEK'S (tap cheek → facial twitch), positive TROUSSEAU'S (BP cuff → carpal spasm), laryngospasm (airway), seizures. Acute tetany → **IV CALCIUM GLUCONATE STAT** (have ready post-op; never IM = tissue necrosis).
**Thyroid function tests**: TSH is most sensitive screening. In primary disease, TSH moves OPPOSITE to hormone level: LOW TSH = hyper, HIGH TSH = hypo (feedback intact). Free T4/T3 confirm; RAIU scan shows uptake pattern (high in Graves').
**NLE loves PAIRED OPPOSITES**: SIADH/DI, hyperthyroid/hypothyroid, thyroid storm/myxedema coma, hyperparathyroid/hypoparathyroid. Learn the hormone's function, reason out the signs in EACH DIRECTION, know the LIFE-THREATENING CRISES. Test by covering one side of comparison table and reciting the other.

Last Minute Tips

**When you see SODIUM DERANGEMENT (hyponatremia/hypernatremia), think ADH**: Low Na + concentrated urine = SIADH (fluid restrict + slow correction). High Na + dilute urine = DI (fluid replace + DDAVP). Neuro signs (confusion, seizures) are the RED FLAG that you're running out of time.
**Post-op neck surgery ALWAYS screen for HYPOCALCEMIA**: Chvostek's/Trousseau's positive = parathyroid damage. Don't wait for symptoms; prophylactically have calcium ready. Laryngospasm from hypocalcemia can steal the airway—it's a real emergency in the ward.
**'Slowly correct' sodium in SIADH**: The exam loves testing whether you know the RATE of correction (≤8–10 mEq/L per 24 hrs). Over-rapid correction → osmotic demyelination. Over-slow correction → seizures from hyponatremia. Know the Goldilocks zone.
**Levothyroxine timing is SACRED**: empty stomach, morning, 30–60 min before food, same time daily. If patient asks 'Can I take it with my vitamins?' → NO. If 'Can I take it at dinner?' → NO. This is a classic NLE trap where students lose points by not knowing the drug timing.
**In thyroid storm, NEVER give aspirin for fever**: aspirin displaces thyroid hormone from binding proteins → WORSENS the crisis. Use tepid sponging, cooling blankets, cool IVs. This is a **high-yield** fact that separates exam passers from those who don't.

Comparison Tables

Rows

Values

TOO MUCH (excess)
TOO LITTLE (deficiency) or renal unresponsiveness

Property

ADH Level

Values

RETAINS water (concentrated urine)
LOSES water (dilute polyuria 3–20 L/day)

Property

Water Handling

Values

LOW (dilutional hyponatremia <135 mEq/L)
HIGH (hypernatremia >145 mEq/L)

Property

Serum Na+

Values

LOW (<280 mOsm/kg)
HIGH (>295 mOsm/kg)

Property

Serum Osmolality

Values

HIGH (concentrated, inappropriate for low serum osmolality)
LOW (dilute)

Property

Urine Osmolality

Values

HIGH (>1.020)
LOW (1.002–1.005)

Property

Urine Specific Gravity

Values

SUPPRESSED (patient not thirsty despite low Na+)
INTENSE (patient desperately thirsty despite polyuria)

Property

Thirst

Values

SCLC, meningitis, CNS disorders, drugs (SSRIs, carbamazepine), surgery, pulmonary disease
Central: pituitary surgery, head trauma, tumors. Nephrogenic: lithium, amphotericin, renal disease

Property

Causes

Values

FLUID RESTRICTION (cornerstone); hypertonic saline for severe hyponatremia; vaptans; correct slowly (≤8–10 mEq/L per 24 hrs)
REPLACE FLUIDS; central DI → DDAVP (desmopressin); nephrogenic → high fluids + NSAIDs/thiazides

Property

Primary Management

Values

Cerebral edema, seizures, coma (from severe hyponatremia <120 mEq/L)
Hypovolemic shock, severe hypernatremia (>160 mEq/L)

Property

Acute Complication

Values

SIADH = SOAKED (retains water, low Na+, restrict fluids)
DI = DRY (loses water, high Na+, replace fluids + DDAVP)

Property

Memory Hook

Columns

Feature
SIADH
Diabetes Insipidus

Table Title

SIADH vs Diabetes Insipidus (ADH Disorders)

Rows

Values

SPED UP (↑metabolic rate, ↑O2 consumption)
SLOWED DOWN (↓metabolic rate)

Property

Metabolism

Values

LOSS (despite ↑appetite)
GAIN (despite normal/↓appetite)

Property

Weight

Values

HEAT INTOLERANCE (diaphoresis, warm moist skin)
COLD INTOLERANCE (prefers warm environment)

Property

Temperature Tolerance

Values

TACHYCARDIA, palpitations, AFib, tachyarrhythmias
BRADYCARDIA, slow HR

Property

Heart Rate

Values

DIARRHEA (speedy transit)
CONSTIPATION (slow transit)

Property

GI Motility

Values

NERVOUSNESS, irritability, anxiety, insomnia, tremor
DEPRESSION, lethargy, slowed thinking, cognitive fog

Property

Mood/Cognition

Values

WARM, moist, fine hair; smooth skin
COLD, dry, coarse hair; thin/brittle; myxedema (puffy face)

Property

Skin

Values

LOW (<0.5 mIU/L in primary disease)
HIGH (>5 mIU/L in primary disease)

Property

Lab: TSH

Values

HIGH (↑T4, ↑T3)
LOW (↓T4, ↓T3)

Property

Lab: Free T4/T3

Values

Graves' disease (autoimmune; includes exophthalmos + goiter)
Hashimoto's thyroiditis (autoimmune)

Property

Most Common Cause

Values

Antithyroid drugs (methimazole/PTU), beta-blockers, radioactive iodine, or thyroidectomy
Lifelong levothyroxine (empty stomach, morning, never stop abruptly)

Property

Main Treatment

Values

THYROID STORM: fever 40–41°C, severe tachycardia, delirium → cool (NOT aspirin), propranolol, PTU, iodine, steroids
MYXEDEMA COMA: hypothermia <32°C, hypotension, respiratory depression, coma → IV levothyroxine, airway support, warm gradually, IV glucose

Property

CRISIS

Columns

Feature
Hyperthyroidism (Too Much T3/T4)
Hypothyroidism (Too Little T3/T4)

Table Title

Hyperthyroidism vs Hypothyroidism (Thyroid Hormone Disorders)

Rows

Values

HIGH (↑PTH drives hypercalcemia)
LOW (↓PTH allows Ca to fall)

Property

PTH Level

Values

HIGH (hypercalcemia, >10.5 mg/dL)
LOW (hypocalcemia, <8.5 mg/dL)

Property

Serum Calcium

Values

LOW (PTH excretes phosphate)
HIGH (no PTH to excrete phosphate)

Property

Serum Phosphate

Values

DEMINERALIZATION: osteoporosis, fractures, bone pain
Usually normal (unless prolonged/severe)

Property

Bone Effects

Values

CONSTIPATION, nausea, polyuria (nephrolithiasis), GI ulcers, pancreatitis
Usually none unless symptomatic hypocalcemia

Property

GI Symptoms

Values

WEAKNESS, fatigue; altered mental status (confusion, mood changes)
TETANY: numbness/tingling, muscle cramps, positive Chvostek's/Trousseau's, laryngospasm, seizures

Property

Neuro/Muscle

Values

POLYURIA (high urinary calcium), kidney STONES (most common)
Variable (depends on cause)

Property

Kidney/Urine

Values

BONES (fractures), STONES (nephrolithiasis), GROANS (GI), MOANS (psychiatric)
Acute TETANY post-neck surgery; perioral/finger tingling; carpal spasm

Property

Classic Presentation

Values

Parathyroid adenoma or hyperplasia; less common: malignancy (PTHrP), vitamin D excess
Post-thyroidectomy/parathyroidectomy (parathyroid gland damage)

Property

Most Common Cause

Values

IV saline + loop diuretics (furosemide) → calcium excretion; bisphosphonates/calcitonin; PARATHYROIDECTOMY (definitive)
ACUTE tetany: IV CALCIUM GLUCONATE; chronic: oral calcium + active vitamin D (calcitriol); seizure/laryngospasm precautions

Property

Main Treatment

Values

HYPERCALCEMIC CRISIS: polyuria/dehydration, cardiac arrhythmias (shortened QT), altered mental status, renal failure
TETANY/LARYNGOSPASM: loss of airway, respiratory failure; seizures

Property

CRISIS

Columns

Feature
Hyperparathyroidism (Too Much PTH)
Hypoparathyroidism (Too Little PTH)

Table Title

Hyperparathyroidism vs Hypoparathyroidism (PTH Disorders)

Rows

Values

Poorly controlled HYPERTHYROIDISM (excess T3/T4)
Untreated/decompensated HYPOTHYROIDISM (deficient T3/T4)

Property

Underlying Disease

Values

Infection, surgery, stress, iodine exposure, drug withdrawal (antithyroid)
Cold exposure, infection, sedatives, levothyroxine discontinuation

Property

Precipitant

Values

HIGH FEVER: 39.5–41°C (hyperpyrexia); can reach dangerous extremes
LOW TEMPERATURE: profound HYPOTHERMIA (<32°C)

Property

Temperature

Values

SEVERE TACHYCARDIA (HR 140+), arrhythmias (AFib), hypertension, palpitations, chest pain
PROFOUND BRADYCARDIA, HYPOTENSION, shock

Property

Cardiovascular

Values

AGITATION, delirium, psychosis, confusion, restlessness
LETHARGY, COMA, markedly depressed consciousness

Property

Mental Status

Values

Vomiting, diarrhea, hyperglycemia (from stress), increased O2 demand
Constipation, hypoglycemia, decreased O2 consumption, respiratory depression (CO2 retention)

Property

GI/Metabolic

Values

Increased breathing from ↑metabolism; pulmonary edema risk
HYPOVENTILATION, respiratory depression, CO2 retention, respiratory failure risk

Property

Respiratory

Values

HIGH if untreated (can rapidly deteriorate)
HIGH if untreated (often mimics death—may be misdiagnosed as terminal)

Property

Mortality

Values

COOLING (tepid sponging, cool IVs, fans—NOT ice; NOT aspirin), IV fluids, propranolol (beta-blocker), PTU (antithyroid), Lugol's iodine, corticosteroids; treat trigger
IV LEVOTHYROXINE (loading dose 200–500 mcg IV), airway/ventilation support, WARM GRADUALLY (passive; NOT active), IV glucose, IV fluids, corticosteroids; treat trigger

Property

Management

Values

Continuous cardiac monitoring (arrhythmia watch), temp Q15 min, neuro checks, labs (TSH, free T4, CBC, glucose)
Continuous monitoring (may mimic brain death—keep resuscitating), temp q30 min, slow rewarming, labs (TSH, free T4, glucose, cortisol)

Property

Monitoring

Columns

Feature
Thyroid Storm (Thyrotoxic Crisis)
Myxedema Coma (Hypothyroid Crisis)

Table Title

Thyroid Storm vs Myxedema Coma (Thyroid Emergencies)

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Adrenal Disorders

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