Electrolyte abnormalities and progressive renal failure in a cancer patient

CASE PRESENTATION A 49-year-old man was referred for evaluation of rising plasma creatinine. The patient had undergone a partial gastrectomy 4 years previously, for resection of a gastrointestinal stromal tumor. He was diagnosed with recurrent disease, including hepatic involvement 6 months before presentation at the renal clinic, for which he was initially treated with imatinib mesylate (Gleevec, Novartis Pharmaceuticals, East Hanover, NJ, USA). Two months later, his regimen was changed to ifosfamide (2500 mg/m on days 1–3), doxorubicin (20 mg/m on days 1–3), and mesna (600 mg/m on days 1–3) after the tumor was reclassified as an inflammatory myofibroblastic sarcoma. At this time, chemistries were notable for creatinine 0.9 mg/dl, calcium 10.4 mg/dl, and albumin of 3.2 g/dl. Urine dipstick was notable for trace albuminuria. Over the next 6 weeks, he received three cycles of ifosfamideþdoxorubicinþmesna. He also received a single 90 mg dose of pamidronate for hypercalcemia (presumed to be caused by his underlying malignancy). His first course of chemotherapy was complicated by urinary retention, which resolved spontaneously, and by neutropenic fever (for which he received a single dose of gentamicin, 110 mg). In addition, he had mild hypomagnesemia and hypokalemia. One week after completing the third course of ifosfamideþdoxorubicin þmesna, the creatinine increased from 1.0 to 1.5 mg/dl, the K was 2.5 mmol/l and a urine dipstick revealed trace proteinuria and hematuria. Oral potassium was prescribed and the chemotherapy regimen was switched to gemcitabine and docetaxel (1000 and 40 mg/m on days 1 and 8 of 21-day cycle, respectively) because of a concern regarding ifosfamide-induced encephalopathy. The first cycle of gemcitabine and docetaxel was complicated by thrombocytopenia requiring dose reductions by 25%. The creatinine increased to 2.0 mg/dl after the first cycle and to 2.4 mg/dl after the second cycle (Figure 1), and the patient was then referred to the renal clinic. The patient’s medical history included attention deficit disorder for which he took methylphenidate. Other medications were loratidine and darbepoetin alpha; there were no non-steroidal anti-inflammatory drugs or herbal preparations. He reported allergies to ciprofloxacin, penicillin, tetracycline, and minocycline. He had smoked up to one pack of cigarettes a day for 10 years, quitting 20 years ago. There was no family history of renal disease or cancer. Examination showed a white male with pulse 100/min and blood pressure 158/88. The jugular veins were not distended. The lungs were clear to auscultation; his heart had a regular rhythm with normal heart sounds and no murmurs or gallops. The abdomen was notable for a firm, non-tender mass in the right upper quadrant. There was trace ankle edema. No skin rashes were noted. Laboratory studies revealed: white blood count 3.5 10/l, hemoglobin 9.2 g/dl, platelets 40 10/l, sodium 141 mmol/l (normal range, 136–142), potassium 3.6 mmol/l (3.5–5.0), chloride 109 mmol/dl (98–108), bicarbonate 25 mmol/dl (23–32), blood urea nitrogen 22 mg/dl (9–25), creatinine 2.4 mg/dl (0.7–1.3), glucose 107 mg/dl (54–118), calcium 11.0 mg/dl (8.8–10.5), phosphate 2.3 mg/dl (2.4–5), albumin 3.5 g/dl (3.7–5.4), and immunoreactive parathyroid hormone 11 pg/ml (11–80). Urine dipstick revealed pH 5.5, specific gravity 1.015, no glucose or ketones, 1þ blood, 2þ protein, no nitrites or leukocyte esterase. The urine sediment showed 15–20 dark granular casts and 2–5 red blood cells per high power field. The spot urine protein/ creatinine ratio was 1.6. Lactate dehydrogenase and haptoglobin were normal. Parathyroid hormone related peptide was undetectable; 25-OH and 1,25-OH vitamin D levels were 25 ng/ml (normal range, 20–57) and 57 pg/ml (15–75), respectively. A peripheral blood smear did not reveal any schistocytes. A recent computed tomography scan of the abdomen (for tumor restaging) demonstrated normal sized kidneys without hydronephrosis. http://www.kidney-international.org t h e r e n a l c o n s u l t