Uveitis in Nephrology: A Presentation of a Case of Tubulointerstitial Nephritis with Uveitis (TINU)

Introduction: Tubulointerstitial nephritis with uveitis is a rare oculorenal disease. Patients with TINU usually present with kidney involvement, followed by ocular involvement. Here we presented a case of TINU initially presented with uveitis. Case Description: A 24-year-old female patient with a red eye, pain, and blurry vision was diagnosed with uveitis/episcleritis a few months ago and was treated with prednisone and cyclopentolate eye drops with mild improvement in her symptoms. She visited her primary care physician recently for the evaluation of intermittent vomiting that started a few weeks ago with decreased oral intake. Laboratory tests revealed elevated acute phase reactant (ESR> 120 mm/h, CRP; 120 mg/dL), anemia (10.5 g/dl), significant renal failure (BUN: 43 mg/dl, creatinine 6.0 mg/dl), urinalysis was positive for WBCs, urine microscopy showed many hyaline casts, a few granular casts, and a WBC. The urine protein-to-creatinine ratio was 457 mg/day. The antinuclear antibody (ANA), and antineutrophil cytoplasmic antibody (ANCA) results were negative, and the angiotensin-converting enzyme level was within normal levels. Chest CT and echocardiography findings were unremarkable. Renal biopsy findings were consistent with acute interstitial nephritis (AIN), non-caseating granuloma, and significant eosinophilia (Figure 1). In the setting of recent uveitis with AIN, the patient was diagnosed with TINU. Pulse steroid (methyl-prednisone, 250 mg IV) was initiated, followed by a steroid tapering regimen (1 mg/kg PO). The patient was followed up in our outpatient clinic with normal kidney function. Discussion: TINU should be considered in the differential diagnosis with other oculorenal diseases including Sjogren’s syndrome, sarcoidosis, tuberculosis, and Behcet’s disease.