Adrenal Cortical Disorders

Adrenal Cortex: Basics - Gland Essentials

• Adrenal Cortex Layers (Outer to Inner) & Primary Products:
  • Zona Glomerulosa (ZG): Mineralocorticoids (e.g., Aldosterone - salt balance).
  • Zona Fasciculata (ZF): Glucocorticoids (e.g., Cortisol - sugar metabolism).
  • Zona Reticularis (ZR): Androgens (e.g., DHEA - sex characteristics).
• 📌 Mnemonic (GFR → Hormones): Glomerulosa, Fasciculata, Reticularis → Salt, Sugar, Sex.

⭐ Embryological Origin: Adrenal cortex develops from mesoderm; adrenal medulla from neural crest cells.

Cushing's Syndrome - Moon Face Mayhem

⭐ Most common cause of Cushing's syndrome is exogenous glucocorticoid administration; most common endogenous cause is Cushing's disease (pituitary adenoma).

• Chronic cortisol excess. 📌 CUSHINGOID features: Central obesity, Moon facies, Buffalo hump, Purple striae, Hypertension, Hyperglycemia, Osteoporosis, Amenorrhea, Immunosuppression.
• 
• Diagnosis:
  • Screening: 24-hr Urine Free Cortisol (UFC), Late-night salivary cortisol, Low-dose Dexamethasone Suppression Test (LDDST - 1mg).
  • Localization:
    • Plasma ACTH: If low (e.g., <5 pg/mL) → Adrenal cause (ACTH-independent). Proceed to adrenal imaging.
    • If normal/high (e.g., ≥5 pg/mL) → ACTH-dependent. Differentiate pituitary (Cushing's disease) vs. ectopic ACTH with High-dose DST (HDDST - 8mg; pituitary source typically suppresses) and/or CRH stimulation test.

Hyperaldosteronism & CAH - Salty Surges & Enzyme Snags

• Hyperaldosteronism (Conn's Syndrome):

  • Primary: ↑Aldosterone, ↓Renin.
  • Causes: Adrenal adenoma (most common), bilateral adrenal hyperplasia.
  • Sx: Resistant HTN, unexplained ↓K+, metabolic alkalosis. 📌 Conn's: Salty (HTN), Low K+, High Aldo.
  • Dx: Aldosterone:Renin Ratio (ARR) > 20-30 (ng/dL per ng/mL/hr); confirmatory tests (e.g., saline infusion).
  • Rx: Spironolactone/Eplerenone; surgery for adenoma.

• Congenital Adrenal Hyperplasia (CAH):

  • Autosomal recessive enzyme defects in cortisol synthesis → ↓Cortisol → ↑ACTH → adrenal hyperplasia & precursor shunting.
  • 
  • ⭐ > 21-hydroxylase deficiency is the most common cause of Congenital Adrenal Hyperplasia.
  • Key Types & Features:

Adrenal Insufficiency - Energy Crisis Central

⭐ Hyperpigmentation and hyperkalemia are characteristic of primary (Addison's) but not secondary adrenal insufficiency.

• Acute Crisis: Hypotension, shock. IV hydrocortisone.
• ACTH Stim Test: Primary: Cortisol no rise > 20 µg/dL.

Adrenal Cortical Neoplasms - Cortical Growth Alarms

High‑Yield Points - ⚡ Biggest Takeaways

• Cushing's syndrome: Excess cortisol from pituitary adenomas (Cushing's disease), adrenal tumors, or ectopic ACTH.
• Conn's syndrome: Primary hyperaldosteronism causing hypertension, hypokalemia, low renin.
• Addison's disease: Primary adrenal insufficiency with ↓cortisol/aldosterone, ↑ACTH, hyperpigmentation, hypotension.
• Waterhouse-Friderichsen syndrome: Acute adrenal hemorrhage, classically with N. meningitidis sepsis.
• CAH: Most common is 21-hydroxylase deficiency leading to virilization, salt wasting.
• Adrenocortical carcinoma: Differentiated from adenoma by large size, necrosis, invasion.