Hypercalcemia caused by Pneumocystis jirovecii pneumonia

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M.M.T. van Leent, N. Goos-Peek, K. van der Putten, S. Lobatto, M.S.S. Yo

Woensdag 20 april 2016

15:30 - 15:40u in Zaal 0.5

Categorieën: Parallelsessie

Parallel sessie: Parallelsessie 4: Case reports/research

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Case: A 58-year-old patient with a kidney transplant for diabetic nephropathy was found to have hypercalcemia (2,98 mmol/l) at follow-up visit. Further laboratory tests showed a stable kidney function and sedimentation rate of 35mm/h. His only complaint was fatigue. Physical examination was unremarkable with no fever or dyspnea. Chest X-ray showed vague bilateral basal consolidations. Differential diagnosis included a (atypical) respiratory infection and left sided heart failure. Azithromycin and furosemide were started. Hypercalcemia was thought to be induced by the combined use of hydrochlorothiazide, calcium and vitamin D, which were all discontinued.

However, the hypercalcemia persisted and he had complaints of progressive dyspnea. A PET scan showed diffuse increased FDG uptake of the lung parenchyma. By bronchoalveolar lavage the diagnosis of Pneumocystis jirovecii pneumonia (PJP) was made and high dose trimethoprim/sulfamethoxazole and prednisone were started. He soon improved and serum calcium levels had normalized one month later.

Discussion: Hypercalcemia is a common complication after kidney transplantation, most often caused by persistent tertiary hyperparathyroidism. This case report shows that PJP can also cause significant hypercalcemia. The proposed mechanism is that granulomatous inflammation causes excess extra-renal 1,25-dihydroxyvitamin D [1,25-(OH)2D] production by macrophages, also seen in sarcoidosis. Indeed in our patient, PTH and 25-hydroxyvitamin D were low to normal, while 1,25-(OH)2D levels turned out to be elevated (209 pmol/L). Moreover, by treating the pneumonia effectively, the blood calcium levels normalized.

Conclusion: This case report shows that Pneumocystis jirovecii pneumonia can cause hypercalcemia and that this can be an early sign of the infection.