Endocrine
Adrenal Disorders
Endocrine

Adrenal Disorders

Insufficiency (Addison, secondary), CAH, Cushing, pheochromocytoma, hyperaldosteronism.

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◆Primary adrenal insufficiency (Addison)

  • •Autoimmune (most common in developed), TB (developing), adrenal hemorrhage (Waterhouse-Friderichsen with meningococcemia), metastases, drugs (ketoconazole)
  • •Both cortisol AND aldosterone deficient → hypotension + hyperpigmentation (↑ACTH/MSH) + hyperK + hyponatremia + hypoglycemia + eosinophilia
  • •Cosyntropin (ACTH) stimulation test: cortisol fails to rise
  • •Treat: hydrocortisone (glucocorticoid) + fludrocortisone (mineralocorticoid)

◆Secondary adrenal insufficiency

  • •Pituitary failure → low ACTH → low cortisol; aldosterone INTACT (RAAS independent)
  • •NO hyperpigmentation, NO hyperK
  • •Causes: pituitary tumor, Sheehan, sudden steroid withdrawal
  • •Treat: hydrocortisone only (no need for fludrocortisone)

◆Adrenal crisis

  • •Acute decompensation: severe hypotension + AMS + abdominal pain + hyperK + hypoglycemia
  • •Trigger: infection, surgery, trauma, sudden steroid withdrawal
  • •Treat: IV hydrocortisone 100 mg + IV fluids + dextrose; don't wait for labs
  • •Always 'stress dose' steroids before surgery in chronic steroid users

◆Congenital adrenal hyperplasia (CAH)

  • •21-hydroxylase deficiency (most common, 95%): low cortisol + low aldosterone + HIGH androgens → salt wasting + virilization in girls (ambiguous genitalia); ↑ 17-OHP
  • •11-β-hydroxylase: low cortisol + HIGH 11-deoxycorticosterone (acts as mineralocorticoid) → HTN + low K + virilization
  • •17-α-hydroxylase: low cortisol + LOW androgens → HTN + low K + lack of secondary sex characteristics
  • •Treat: glucocorticoid replacement (hydrocortisone) ± mineralocorticoid (fludrocortisone) for 21-OH

◆Cushing syndrome

  • •Causes: exogenous steroids (most common); endogenous: pituitary adenoma (Cushing DISEASE — 70%), ectopic ACTH (small cell lung CA), adrenal adenoma
  • •Features: central obesity, moon face, buffalo hump, purple striae, easy bruising, HTN, hyperglycemia, osteoporosis, proximal weakness, depression
  • •Screening: 24-hr urine free cortisol, late-night salivary cortisol, low-dose dex suppression
  • •Localize: ACTH level. Low → adrenal source. High → ACTH-dependent (pituitary vs ectopic); high-dose dex suppression: suppresses pituitary (DISEASE), doesn't suppress ectopic
  • •Treat: surgical resection of source; ketoconazole/metyrapone for medical management

◆Pheochromocytoma

  • •Catecholamine-secreting adrenal medulla tumor
  • •Classic '5 P's': Paroxysmal HTN + Palpitations + Perspiration + Pain (headache) + Pallor
  • •10% rule: 10% bilateral, 10% malignant, 10% extra-adrenal, 10% familial
  • •Associations: MEN 2A/2B, NF1, VHL
  • •Diagnose: 24-hr urine metanephrines (or plasma free metanephrines)
  • •Localize: CT/MRI; MIBG scan if not seen
  • •Treat: alpha-blockade FIRST (phenoxybenzamine) for 10–14 days → THEN beta-blockade → THEN surgical resection. NEVER β-block first (unopposed alpha → hypertensive crisis)

◆Primary hyperaldosteronism (Conn)

  • •Adrenal adenoma or bilateral hyperplasia → ↑ aldosterone → HTN + HYPOKALEMIA + metabolic alkalosis
  • •Aldosterone:renin ratio elevated (>20)
  • •Adrenal vein sampling to distinguish unilateral (adenoma → adrenalectomy) vs bilateral (hyperplasia → spironolactone)
  • •Suspect in HTN + spontaneous hypokalemia OR resistant HTN

Adrenal insufficiency: primary vs secondary

FeaturePrimary (Addison)Secondary (pituitary)
SiteAdrenalPituitary
CortisolLowLow
AldosteroneLOW (hyperK, hypoNa)Normal (RAAS intact)
ACTHHIGHLOW
HyperpigmentationYES (↑ MSH from POMC)NO
HyperkalemiaYESNO
TreatmentHydrocortisone + fludrocortisoneHydrocortisone only

Congenital adrenal hyperplasia

Enzyme defectCortisolMineralocorticoid effectAndrogensBP / K
21-hydroxylase (most common)LowLow (salt wasting)HIGH (virilization)Low BP, ↑K
11-β-hydroxylaseLowHIGH (DOC builds up)HIGHHIGH BP, ↓K
17-α-hydroxylaseLowHIGHLOW (no secondary sex chars)HIGH BP, ↓K

High-yield pearls

  • ◆Hyperpigmentation in adrenal insufficiency = PRIMARY (high ACTH/MSH from POMC)
  • ◆Always α-block BEFORE β-block in pheochromocytoma
  • ◆Cushing test ladder: screen (UFC, salivary cortisol, low-dose dex) → measure ACTH → high-dose dex / MRI
  • ◆Stress-dose steroids: anyone on >5 mg/day prednisone for >3 weeks in past year
  • ◆Sheehan syndrome: postpartum hemorrhage → pituitary infarction → no lactation (low prolactin) + amenorrhea + adrenal insufficiency
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