Navigating the diagnostic maze of renal tuberculosis in advanced chronic kidney disease: A case report

Renal tuberculosis (TB) is a rare extrapulmonary manifestation of Mycobacterium tuberculosis, often leading to irreversible renal damage due to delays in diagnosis. The present study reports the case of a 72-year-old male patient with pre-existing type II diabetes mellitus, hypertension, and stage G3bA0 chronic kidney disease (CKD), who manifested with a sub-acute deterioration of renal function necessitating renal replacement therapy. The initial workup for uropathies, including repeated urine cultures, was negative despite the clinical suspicion, presenting the hallmark sign of sterile pyuria. The QuantiFERON-TB Gold test revealed a highly positive value, confirmed in two measurements, followed by contrast-enhancing computed tomography, which revealed a subtle hypodense area consistent with early granulomatous inflammation, supporting the diagnosis of renal TB as the sole site of infection. The case described herein underscores the critical need to prioritize renal TB in the differential diagnosis for high-risk patients with CKD with unexplained subacute renal function decline and sterile pyuria. The present case report highlights the robust diagnostic utility of the QuantiFERON test over conventional methods such as the tuberculin skin test in immunocompromised settings (e.g. advanced CKD), advocating for its earlier and routine deployment to prevent irreversible renal failure.