Endocrine pathology

Pituitary Pathology - Master Gland Mayhem

• Pituitary Adenoma: Benign tumor, most common cause of hyperpituitarism.
  • Prolactinoma is the most frequent type; presents with galactorrhea, amenorrhea, and ↓libido.
• Hypopituitarism: Gland failure.
  • Causes: Sheehan syndrome (postpartum necrosis), apoplexy (hemorrhage), empty sella syndrome.
• Posterior Lobe Syndromes: ADH dysregulation.
  • Diabetes Insipidus (↓ADH), SIADH (↑ADH).

⭐ A pituitary adenoma compressing the optic chiasm is a classic cause of bitemporal hemianopsia.

Thyroid Pathology - Highs and Lows

• Hyperthyroidism (Thyrotoxicosis):

  • Graves Disease: Most common cause. Autoimmune via Thyroid-Stimulating Immunoglobulins (TSI).
  • Key signs: Exophthalmos, pretibial myxedema, diffuse goiter.
  • Labs: ↓ TSH, ↑ free T4/T3.

• Hypothyroidism:

  • Hashimoto's Thyroiditis: Most common cause (iodine-sufficient regions). Autoimmune destruction (anti-TPO, anti-thyroglobulin Abs).
  • Labs: ↑ TSH, ↓ free T4/T3.

⭐ Patients with Hashimoto's thyroiditis have an increased risk for B-cell non-Hodgkin lymphoma of the thyroid.

Parathyroid & Calcium - Bones, Stones, Groans

• Primary Hyperparathyroidism: Most often a parathyroid adenoma.
  • Labs: ↑ PTH, ↑ Ca²⁺, ↓ PO₄³⁻, ↑ ALP.
  • 📌 "Bones, stones, groans, psychiatric overtones."
    • Bones: Osteitis fibrosa cystica (brown tumors).
    • Stones: Recurrent calcium kidney stones.
    • Groans: Constipation, peptic ulcers.
• Secondary Hyperparathyroidism: Compensatory ↑ PTH from hypocalcemia.
  • Common cause: Chronic kidney disease.

⭐ Osteitis fibrosa cystica ("brown tumors") results from PTH-induced osteoclastic resorption of bone, leading to fibrosis and cystic spaces.

Adrenal Pathology - Cortex & Medulla Chaos

• Cortex Hyperfunction:
  • Cushing's Syndrome (↑Cortisol): Central obesity, striae. Iatrogenic is most common cause.
  • Conn's Syndrome (↑Aldosterone): HTN, ↓K+, metabolic alkalosis.
• Cortex Hypofunction (Addison's):
  • ↓Cortisol & ↓Aldosterone. Hypotension, ↑K+, hyperpigmentation (from ↑ACTH).
• Medulla - Pheochromocytoma:
  • Tumor of chromaffin cells. Rule of 10s: 10% bilateral, 10% extra-adrenal, 10% malignant.
  • 📌 5 P's: Pressure, Pain (headache), Perspiration, Palpitations, Pallor.

⭐ Nelson Syndrome: Post-bilateral adrenalectomy, a pituitary adenoma grows rapidly, causing mass effects and severe hyperpigmentation from ↑↑ACTH.

Endocrine Pancreas - Sweet & Sour Syndromes

• Diabetes Mellitus (DM):
  • Type 1: Autoimmune β-cell destruction (Insulitis). HLA-DR3 & DR4. ↓Insulin.
  • Type 2: Insulin resistance, relative insulin deficiency. Islet amyloid polypeptide (IAPP) deposits.
• Pancreatic Neuroendocrine Tumors (PanNETs):
  • Insulinoma: Whipple triad (symptoms, hypoglycemia <50 mg/dL, glucose relief).
  • Gastrinoma (ZES): ↑Gastrin → refractory peptic ulcers, diarrhea.
  • Glucagonoma: 📌 5 D's: Dermatitis (necrolytic migratory erythema), Diabetes, DVT, Depression, ↓Weight.
  • VIPoma: WDHA syndrome (Watery Diarrhea, Hypokalemia, Achlorhydria).

⭐ Most insulinomas (>90%) are benign, solitary, and <2 cm.

High‑Yield Points - ⚡ Biggest Takeaways

• Pituitary adenomas are the most common cause of hyperpituitarism; prolactinoma is the most frequent type.
• Papillary thyroid carcinoma, the most common thyroid cancer, is defined by Orphan Annie eye nuclei and psammoma bodies.
• MEN syndromes are key autosomal dominant disorders that cause tumors in multiple endocrine glands.
• Cushing's syndrome (↑cortisol) and Addison's disease (↓cortisol, ↓aldosterone) are cornerstone adrenal disorders.
• Pheochromocytoma is a catecholamine-secreting tumor of the adrenal medulla; remember the Rule of 10s.