Sarcoidosis Renal — ESENeph MCQ

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ModerateChronic Kidney DiseaseSarcoidosis RenalESENeph

A 48-year-old man is found to have persistent hypercalcaemia (corrected Ca 2.82 mmol/L) and an eGFR of 35 mL/min/1.73m2. PTH is suppressed (<0.5 pmol/L). ACE level is elevated. Chest X-ray shows bilateral hilar lymphadenopathy. What is the most likely cause of the renal impairment?

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Correct answer: B — Sarcoidosis with granulomatous interstitial nephritis and/or nephrocalcinosis

The combination of hypercalcaemia with suppressed PTH, elevated ACE level, and bilateral hilar lymphadenopathy is diagnostic of sarcoidosis. Renal involvement in sarcoidosis includes granulomatous interstitial nephritis (the most common histological finding), hypercalcaemia-mediated nephrocalcinosis, and rarely membranous nephropathy. The hypercalcaemia is driven by unregulated 1-alpha-hydroxylase activity in granulomas converting 25-OH vitamin D to 1,25-dihydroxyvitamin D. Treatment is with glucocorticoids.

Reference: KDIGO 2021 – GN Guideline (Chapter 1); Baughman et al 2016 – Sarcoidosis Review