Week 8 – Endocrine Pathology – Study Guide

Key Terms

• Hormone – chemical messenger produced by glands to regulate body functions.
• Hypersecretion – excess hormone production.
• Hyposecretion – deficient hormone production.
• Adenoma – benign glandular tumour; may secrete hormones.
• Adenocarcinoma – malignant glandular tumour.
• Goitre – enlargement of the thyroid gland.
• Acromegaly – GH excess in adults; gigantism if before growth plate closure.
• Cushing’s syndrome – excess cortisol (endogenous or exogenous).

A. Thyroid Disorders

• Grave’s Disease – autoimmune hyperthyroidism caused by TSH-mimicking antibodies.
   – TRH and TSH suppressed; T3/T4 and antibodies elevated.
   – Symptoms: heat intolerance, weight loss, anxiety, tremor, exophthalmos.
• Hypothyroidism – reduced T3/T4 → fatigue, cold intolerance, weight gain, depression, dry skin.
• Goitre – thyroid enlargement due to iodine deficiency, autoimmune disease, or tumour.

B. Pituitary Disorders

• Pituitary adenomas – benign, hormone-secreting tumours.
   – Well-differentiated tumours secrete excess hormones (e.g. GH, ACTH).
   – Poorly differentiated tumours cause deficiency due to compression of normal tissue.
• GH excess:
   – In adults → Acromegaly (enlarged hands, feet, jaw).
   – In children → Gigantism (excessive linear growth).

C. Adrenal Disorders

• Cushing’s Syndrome – excess cortisol due to tumour or corticosteroid use.
   – Features: truncal obesity, moon face, buffalo hump, muscle wasting, osteoporosis, hyperglycaemia, HTN.
• Addison’s Disease – adrenal insufficiency → fatigue, low BP, hyperpigmentation, hyponatraemia, hyperkalaemia.
• Pheochromocytoma – adrenal medulla tumour producing catecholamines → episodic HTN, palpitations, sweating.

D. Pancreatic Disorders

• Diabetes Mellitus:
   – Type I: autoimmune destruction of β-cells → absolute insulin deficiency.
       ▫ Presents in youth; thin; may present with ketoacidosis.
   – Type II: insulin resistance with relative deficiency; associated with obesity & inactivity.
       ▫ Gradual onset; may be reversible early with weight loss.
• Chronic hyperglycaemia → microvascular (retinopathy, nephropathy, neuropathy) & macrovascular (atherosclerosis) damage.

E. Parathyroid Disorders

• Hyperparathyroidism – excessive PTH → hypercalcaemia, bone resorption, renal stones, psychiatric symptoms.
• Hypoparathyroidism – low PTH (post-surgical, autoimmune) → hypocalcaemia, tetany, muscle cramps.
• Secondary hyperparathyroidism – compensatory ↑ PTH due to chronic renal failure or vitamin D deficiency.

F. Other Endocrine Conditions

• Polycystic Ovarian Syndrome (PCOS) – hyperandrogenism, anovulation, insulin resistance.
• Gestational Diabetes – pregnancy-induced insulin resistance.
• Endocrine tumours – may produce multiple hormones (e.g. MEN syndromes).

Key Takeaways / Exam Points

• Graves’ disease = autoimmune hyperthyroidism; Cushing’s = cortisol excess.
• GH excess → acromegaly (adult) or gigantism (child).
• Type I DM = autoimmune β-cell loss; Type II = insulin resistance.
• Hyperparathyroidism → hypercalcaemia; Hypoparathyroidism → hypocalcaemia.
• Chronic endocrine disease often causes systemic metabolic complications.