Atypical Presentation of IgA Nephropathy Mimicking Acute Pyelonephritis.

Background: IgA glomerulonephritis may present with hematuria, flank pain, and fever. This clinical presentation may be easily confused with acute pyelonephritis.

Case Report: We present the case of a 25-year-old female with a typical clinical presentation for acute pyelonephritis (high fever, left flank pain, left costovertebral angle tenderness, hematuria, elevated inflammatory markers, and a hypoenhancing region in the left kidney on contrast-enhanced computed tomography). However, urine and blood cultures were both negative, the serum creatinine was elevated, and the urinalysis revealed significant proteinuria and dysmorphic red blood cells. A kidney biopsy confirmed a diagnosis of IgA nephropathy. She was treated with a combination of lisinopril and methylprednisolone, with good response.

Conclusion: Gross hematuria, especially in the absence of pyuria or bacteriuria, should raise the suspicion for underlying IgA nephropathy, even if the rest of the clinical presentation is typical for a urinary tract infection. The presence of significant proteinuria, red blood cell casts, and dysmorphic red blood cells are useful clues suggesting glomerular disease.