Kidney disease in a child with familial Mediterranean fever: Questions

Excerpt

A 17-year-old male was referred to our clinic due to a 4-day history of macroscopic hematuria and declined kidney function. He was diagnosed with familial Mediterranean fever (FMF) with heterozygote M694V mutation when he was 4 years old, and he had been on colchicine treatment of 1 mg/day since then. Owing to the low dose of colchicine, he still had FMF attacks with fever and abdominal and chest pain in approximately 2- to 3-month intervals. His father was also an FMF patient, but there was no family history of renal amyloidosis. On admission, the patient had hypertension (155/98 mmHg), and physical examination revealed no additional findings, including edema. Serum creatinine was increased (1.72 mg/dL), and creatinine clearance was 66 mL/min/1.73 m². In urinary analysis, 300 mg/L protein with a density of 1008 was observed, and microscopic examination revealed erythrocyte casts with dysmorphic erythrocytes. Despite having nephrotic range proteinuria (72 mg/m²/h), serum albumin levels were within normal range (3.4 g/dL) with normal serum complement (C3: 0.81 g/L and C4: 0.31 g/L) and IgA (1.21 g/L) levels, and negative anti-nuclear antibody and hepatitis serology. Elevated acute phase reactants (CRP: 24 mg/L, erythrocyte sedimentation rate: 97 mm/h, serum amyloid A: 4.4 mg/dL) with a normal white blood count and hemoglobin were observed. Colchicine treatment was increased to 1.5 mg/day to control FMF activity. Because of the nephrotic range proteinuria and kidney failure, a percutaneous kidney biopsy was performed. In light microscopic examination, diffusely thickened glomerular basement membranes and mesangial hypercellularity with cellular crescents (2/29 glomeruli) were observed (Fig. 1a–c). Immunofluorescence examination revealed granular, diffuse peripheral deposits of IgG without C3 and C1q, and no staining was observed with Congo-red dye.

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