Chemical Pathology: Endocrine Cases, OmpathStudy

MOUNT KENYA UNIVERSITY — MEDICAL SCHOOL Programme: Bachelor of Medicine and Bachelor of Surgery, Year 3 Assessment: End of Semester 2 CAT Unit: Chemical Pathology II Date: 23rd March 2026 Reg No: BMS/2023/.. --- Q1. 17-year-old boy, delayed puberty, anosmia, low LH/FSH, low testosterone. A. Klinefelter syndrome B. Kallmann syndrome C. Turner syndrome D. Androgen insensitivity syndrome E. Congenital adrenal hyperplasia Answer: B — Kallmann syndrome Anosmia + hypogonadotropic hypogonadism (low LH/FSH with low testosterone) is the classic combination, due to defective GnRH neuron migration. Klinefelter (A) shows elevated gonadotropins, not low; Turner (C) is a female condition. Q2. Polyuria/polydipsia after head trauma; low urine osmolality, rises after desmopressin. A. Nephrogenic diabetes insipidus B. Central diabetes insipidus C. SIADH D. Psychogenic polydipsia E. Addison disease Answer: B — Central diabetes insipidus Response to desmopressin confirms the kidney can concentrate urine when ADH is supplied — the deficiency is central (post-trauma pituitary/hypothalamic damage). Nephrogenic DI (A) would NOT respond to desmopressin since the kidney itself is unresponsive. Q3. 45-year-old, suprasellar mass, headaches, bitemporal hemianopia. A. Rathke pouch remnants B. Schwann cells C. Thyroid follicular cells D. Adrenal cortex E. Pancreatic β-cells Answer: A — Rathke pouch remnants Craniopharyngioma, the classic suprasellar mass causing chiasmal compression, arises from remnants of Rathke's pouch (embryological precursor of the anterior pituitary). Q4. 28-year-old woman, amenorrhoea, galactorrhoea, markedly raised prolactin. A. Prolactinoma B. Graves disease C. Adrenal adenoma D. Pancreatic NET E. Primary ovarian failure Answer: A — Prolactinoma Classic triad of amenorrhoea-galactorrhoea with markedly elevated prolactin points directly to a prolactin-secreting pituitary adenoma. Q5. Pituitary macroadenoma compressing the optic chiasm most commonly causes: A. Unilateral blindness B. Bitemporal hemianopia C. Homonymous hemianopia D. Central scotoma E. Diplopia only Answer: B — Bitemporal hemianopia Compression at the chiasm affects the decussating nasal retinal fibres bilaterally, causing loss of the temporal visual fields on both sides. Q6. 52-year-old, enlarged hands, prognathism, sweating, elevated IGF-1 — most common cause? A. Ectopic GHRH secretion B. Pituitary somatotroph adenoma C. Adrenal carcinoma D. Thyroid carcinoma E. Pancreatic insulinoma Answer: B — Pituitary somatotroph adenoma The vast majority of acromegaly cases arise from a GH-secreting pituitary adenoma; ectopic GHRH (A) is a rare cause. Q7. 24-year-old woman, weight loss, tremor, palpitations, exophthalmos; TSH suppressed, free T4 elevated. A. Hashimoto thyroiditis B. Graves disease C. Subacute thyroiditis D. Thyroid lymphoma E. Iodine deficiency goitre Answer: B — Graves disease Exophthalmos plus hyperthyroid biochemistry (suppressed TSH, high T4) is specific to Graves disease. Hashimoto (A) typically causes hypothyroidism, not this picture. Q8. Graves disease is driven primarily by antibodies to the: A. Thyroglobulin B. TSH receptor C. Insulin receptor D. ACTH receptor E. PTH receptor Answer: B — TSH receptor Stimulating autoantibodies against the TSH receptor drive continuous thyroid hormone overproduction, the hallmark of Graves disease. Q9. 46-year-old woman, painless goitre, hypothyroid symptoms, positive anti-TPO antibodies. A. Graves disease B. Hashimoto thyroiditis C. Medullary carcinoma D. Follicular adenoma E. Subacute granulomatous thyroiditis Answer: B — Hashimoto thyroiditis Anti-TPO positivity with painless goitre and hypothyroidism is classic for Hashimoto's autoimmune thyroiditis. Q10. 40-year-old woman, hypertension, hypokalaemia, low renin. A. Addison disease B. Conn syndrome C. SIADH D. Cushing disease E. Diabetes insipidus Answer: B — Conn syndrome Primary hyperaldosteronism causes hypertension with hypokalaemia and suppressed renin (due to autonomous aldosterone excess feeding back on the renin-angiotensin axis). Q11. Conn syndrome results from excess: A. Cortisol B. Aldosterone C. Catecholamines D. ACTH E. Thyroxine Answer: B — Aldosterone By definition, Conn syndrome is primary hyperaldosteronism. Q12. 38-year-old, episodic headaches, sweating, palpitations, severe hypertension — best screening test? A. Serum cortisol B. Plasma/urinary metanephrines C. Serum calcitonin D. Serum TSH E. Urinary 5-HIAA Answer: B — Plasma/urinary metanephrines This presentation is classic for pheochromocytoma; metanephrines (catecholamine metabolites) are the standard screening test. Calcitonin (C) screens for medullary thyroid carcinoma; 5-HIAA (E) screens for carcinoid syndrome. Q13. 19-year-old, abdominal pain, Kussmaul breathing, high ketones, metabolic acidosis. A. Hyperosmolar hyperglycaemic state B. Diabetic ketoacidosis C. Addison crisis D. Thyroid storm E. SIADH Answer: B — Diabetic ketoacidosis Kussmaul breathing (compensatory hyp