An unexpected cause of acute kidney injury in a patient with ANCA associated vasculitis.

Diagnostic kidney biopsies sometimes yield clinically unsuspected diagnoses. We present a case of a 69-year-old woman with established ANCA-associated vasculitis (AAV) of 4 years duration who was in clinical remission following cytotoxic therapy and was on maintenance immunosuppression. She presented to the hospital with acute kidney injury (AKI), symptoms suggestive of a systemic vasculitis, and in addition had hypercalcemia, metabolic alkalosis. A relapse in the AAV was suspected but a diagnostic kidney biopsy showed acute tubular necrosis, patchy interstitial inflammation, and calcium phosphate deposits. It was found that the patient recently started consuming large doses of over-the-counter calcium-containing antacids and vitamin Dcontaining multivitamin supplements. Cessation of these drugs led to improvement of renal function to baseline. This case highlights several teaching points: (1) the kidney biopsy can prove to be critically important even in cases where there appears to be a more obvious clinical diagnosis, (2) AK due to calcium-alkali syndrome has characteristic histopathological changes, and (3) that the triad of hypercalcemia, metabolic alkalosis, and AKI is exclusively associated with the ingestion of excessive quantities of calcium-containing antacids. The physician should keep this in mind, and pro-actively seek pertinent medication history from the patient. A brief review of calcium-alkali syndrome is given.

Severe hemorrhagic cystitis associated with prolonged oral cyclophosphamide therapy: case report and literature review.

Severe hemorrhagic cystitis associated with oral cyclophosphamide (CYP) therapy has rarely been reported in the past 20 years, probably because this condition has largely disappeared because of the use of shorter courses of CYP, either oral or IV. Herein, we describe a patient who received 309 g of oral CYP over a 4-year period to treat Wegener's granulomatosis (WG) that initially involved brain, lung, and kidney. She came under our care for the first time when she presented with a one-day history of oliguria and passing blood clots. Severe hemorrhagic cystitis was present. It eventually required cystectomy. Despite her massive CYP exposure her kidney biopsy showed acute crescentic glomerulonephritis. She survived her acute illness only to die 2 months later of acute leukemia. This patient is a reminder that severe hemorrhagic cystitis from oral CYP still exists, and that WG can be resistant to even toxic doses of oral CYP. Alternative therapies are discussed.