The patient did not exhibit fever, weight loss, or night sweats.
A 48-year-old man with no medical history presented to the clinic complaining of progressive fatigue over the past year. He denied any other constitutional symptoms such as fever, weight loss, and night sweats. He emigrated from Croatia 5 years previously and has not seen a physician since. He has never taken any medications, and he denied any history of tobacco, alcohol, or drug use. He has been working in construction for the past 15 years and denied any known exposure to chemicals.
He stated that his deceased mother had “kidney problems” but was unaware of any other family history. On exam, his blood pressure was 145/88 mm Hg, heart rate 92/min, respiration rate 16/min, temperature 98.6°F, saturating 100% on room air. The remainder of his physical exam is unremarkable. Laboratory findings included hemoglobin 8.7 g/dL; MCV 85 fL; creatinine 1.8 mg/dL; and glucose 90 mg/dL.
Urinalysis revealed 2+ glucose, 2+ protein. He had 10-20 erythrocytes/hpf.
Fecal occult blood test (FOBT) was negative. Renal ultrasound showed symmetrically shrunken and smooth kidneys without calcifications.
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This case was prepared by Payam Pourhassani, DO, a Philadelphia internist.
Debelle FD, Vanherweghem JL, Nortier JL. Aristolochic acid nephropathy: a worldwide problem. Kidney Int 2008; 74:158.
This patient’s clinical history and laboratory findings were consistent with long-standing Balkan endemic nephropathy (BEN), a chronic, slowly progressive tuberointerstitial disease thought to have both a genetic and environmental basis. There is a strong association with exposure to aristolochic acid found in Aristolochia clematis, a plant endemic to the Balkan region. Tubular injury leads to proteinuria and glucosuria (in the setting of euglycemia), and decreased glomerular filtration rate. Patients typically develop a normocytic anemia that worsens with time. Shrunken and smooth kidneys can be seen on imaging in chronic disease.
Importantly, kidney biopsy is not necessary to make the diagnosis of BEN as long as the clinical findings are supportive and the patient is from an endemic area or with a positive family history (which his mother may have had). If needed, biopsy in advanced cases would show substantial tubular atrophy with interstitial fibrosis with possible FSGS.
BEN is associated with a high rate of urothelial (transitional cell) carcinoma, thus annual surveillance with urine cytology is recommended. Not everyone with exposure to A. clematis is affected because only some people are genetically predisposed towards nephrotoxicity and carcinogenesis. Although BEN increases the risk of urothelial carcinoma, there is no suggestion that this patient currently has cancer. BEN may progress to hypertension and eventually ESRD, typically after about 20 years.
A negative FOBT suggests that this patient’s normocytic anemia is not related to GI blood loss. Additionally, with this degree of anemia, iron-deficiency would manifest as a microcytic anemia. Screening colonoscopy for colon cancer screening would be recommended in 2 years