Abstract: PUB672
TINU Syndrome: A Diagnosis of Exclusion
Session Information
Category: Nephrology Education
- 1302 Fellows and Residents Case Reports
Authors
- Kapuria, Malavika, Baylor College of Medicine, Spring, Texas, United States
- Dave, Natasha Naresh, Baylor College of Medicine, Spring, Texas, United States
- Raghavan, Rajeev, Baylor College of Medicine, Spring, Texas, United States
Background
With little over 250 cases reported, the diagnosis of Tubulointerstitial Nephritis and Uveitis (TINU) syndrome requires a high index of suspicion. Variable clinical presentations, poorly understood underlying mechanisms and lack of specific laboratory markers make its diagnosis all the more complex.
We report the case of a young female who presented with AKI, anterior uveitis and systemic symptoms, initially misdiagnosed as pyelonephritis, and subsequently diagnosed and treated for TINU syndrome.
Methods
A 33 year-old Hispanic female with no significant past medical history presented with an 11 days history of fever, fatigue, headache, epigastric pain, dysuria, polyarthralgias and bilateral conjunctival injection. CT scan showed bilateral striated nephrogram with perinephric stranding. She was diagnosed with pyelonephritis and discharged on empiric antibiotics.
She presented again 2 days later with no improvement in symptoms. Physical examination was notable for bilateral conjunctival erythema without drainage, epigastric tenderness and wrist synovitis. Serum creatinine was 2.5 mg/dl increased from 1.5 mg/dl 2 days prior (baseline Cr 0.8).
Further work-up including urinalysis revealed a loss of concentrating ability (specific gravity 1.005 decreased from previous 1.023 in 2011) with ‘few’ urine eosinophils. Urine microscopy revealed WBC casts. Renal ultrasound showed preserved kidney sizes with bilateral heterogeneous poor corticomedullary differentiation. Other pertinent labs included elevated CRP (8.94) and ESR (76), negative ANA, and mildly elevated C3 (154) and C4 (46.9). Ophthalmologic evaluation found anterior uveitis with conjunctival injection.
A kidney biopsy showed acute TIN with eosinophils and non-caseating granulomas. Additional work-up for syphilis, tuberculosis, Sjogren’s, HLA-B27, MPO/PR3 ANCA and chest x-ray were negative.
The patient had excellent response to steroids (pulse dose IV steroids for 3 days, followed by PO steroid taper) with improvement in renal function back to baseline within 14 days. She was treated for a total of 6 weeks and remains asymptomatic 2 months post-hospitalization.
Conclusion
TINU is a rare, idiopathic syndrome and remains a diagnosis of exclusion. This case exemplifies the variety of presenting signs/symptoms and the degree of renal dysfunction associated with TINU, and highlights the need for a systematic approach to ruling out alternative diagnoses.