Endocrinology & Renal Medicine Flashcards

A patient with known SLE presents with a butterfly rash, arthritis, positive anti-dsDNA, and low complement levels (C3, C4). What does this combination suggest?

Answer: Active lupus nephritis

Active SLE is indicated by rising anti-dsDNA titres, falling complement (C3/C4 consumed by immune complex deposition), and clinical features. The combination of butterfly rash, arthritis, high anti-dsDNA, and low complement raises concern for active disease including lupus nephritis, requiring urinalysis and renal biopsy consideration.

Which finding on ANCA testing is associated with granulomatosis with polyangiitis (Wegener's)?

Answer: c-ANCA (anti-PR3)

c-ANCA directed against proteinase 3 (PR3) is associated with granulomatosis with polyangiitis (GPA, formerly Wegener's). p-ANCA (anti-MPO) is associated with microscopic polyangiitis and eosinophilic granulomatosis with polyangiitis (Churg-Strauss). Both are ANCA-associated vasculitides.

Which medication should be initiated in all patients with CKD and proteinuria (ACR >3 mg/mmol) regardless of blood pressure?

Answer: Enalapril (ACE inhibitor) or ARB

ACE inhibitors and ARBs are recommended for all patients with CKD and significant proteinuria as they have nephroprotective effects independent of blood pressure lowering, reducing intraglomerular pressure and proteinuria. They are contraindicated in bilateral renal artery stenosis.

A 35-year-old woman presents with hypertension, hypokalaemia, and metabolic alkalosis. 24-hour urinary aldosterone is elevated with suppressed renin. What is the most likely diagnosis?

Answer: Primary hyperaldosteronism (Conn's syndrome)

Primary hyperaldosteronism (Conn's syndrome) is characterised by hypertension, hypokalaemia, metabolic alkalosis, elevated aldosterone, and suppressed renin. The aldosterone:renin ratio (ARR) is the screening test of choice. Adrenal adenoma is the most common cause; bilateral hyperplasia is the second.

A patient with end-stage renal disease on haemodialysis has a haemoglobin of 82 g/L. What is the most likely cause of anaemia?

Answer: Erythropoietin deficiency from reduced renal production

Anaemia of chronic kidney disease is primarily caused by reduced erythropoietin (EPO) production by the failing kidneys, leading to normocytic normochromic anaemia. Treatment involves recombinant EPO (e.g., darbepoetin), with iron supplementation to support erythropoiesis.

Which HLA type is strongly associated with ankylosing spondylitis?

Answer: HLA-B27

HLA-B27 is present in approximately 90–95% of patients with ankylosing spondylitis in the UK Caucasian population. Although it has high sensitivity for AS, it has low specificity as 8% of the general population carry HLA-B27 without developing AS. Its exact pathogenic role remains under investigation.