A 34-year-old African man was referred to our hospital because of microscopic hematuria identified at an annual health checkup at his workplace. The patient had no significant past medical history and was not taking any medications. The patient gave written informed consent to be included in this case report.
Upon initial routine workup, the patient's HIV test was positive. Subsequent blood tests showed CD4 count was 139 cells/muL and viral load was 5.1x104/mm3. The patient's serum creatinine level was 0.86 mg/dL, with blood urea nitrogen of 10.1 mg/dL. Urinalysis showed red blood cell (RBC) 3+ and urinary sediment showed dysmorphic RBCs (>100/high power field) with RBC casts and absence of white blood cells. Urine beta2-microglobulin was 913 mug/L, urine N-acetyl-beta-d-glucosaminidase was 14.9 U/L, and urine protein was 0.217 g/d. The patient was subsequently diagnosed with pulmonary tuberculosis and was treated with a standard regimen including four drugs for 2 months, followed by isoniazid and rifampin for 4 months.
Because of persistent hematuria, the patient was hospitalized to undergo renal biopsy. The histopathological analysis revealed focal interstitial infiltration of lymphocytes and plasma cells in the renal cortex as well as in the corticomedullary junction, accompanied by mild tubulitis without microcysts (Figure 1). No tubular necrosis was observed, with erythrocytic casts and flattened tubular epithelium (Figure 2). Analysis of glomeruli showed no evidence of podocyte hypertrophy, glomerular collapse, or endocapillary hypercellularity (Figure 2). These findings were consistent with the diagnosis of focal and mild tubulointerstitial nephritis. Ziehl-Neelsen staining of the biopsied specimens was negative, and there were no pathological findings suggestive of tuberculosis.
Two weeks after the initiation of treatment for tuberculosis, antiretroviral therapy (ART), including lamivudine, abacavir, and dolutegravir, was started. The 6-month treatment for tuberculosis was completed successfully. Eight months after the initiation of ART, urinary levels of beta2-microglobulin and N-acetyl-beta-d-glucosaminidase normalized and microscopic hematuria resolved completely.