Nephrotic syndrome with focal segmental glomerulosclerosis after an insect bite

Focal segmental glomerulosclerosis (FSGS) is a glomerular disease defined by a characteristic histologic pattern that occurs either as a primary kidney disease (primary FSGS) or as a result of a systemic illness (secondary FSGS). Proteinuria, often in the nephrotic range, is the hallmark of FSGS. The occurrence of nephrotic syndrome after an insect sting is rarely reported in the literature. We present a case of nephrotic syndrome with focal segmental glomerulosclerosis with a glomerular tip lesion developing after an insect bite.

A 51-year-old Caucasian female was bitten by an insect on her left leg, which immediately became swollen. Generalized edema developed and she was admitted for further investigations. Urinary 24-h protein excretion was 7 g. Percutaneous renal biopsy was performed and showed focal segmental glomerulosclerosis of the tip variant. Nephrotic syndrome was steroid-resistant, and when we added cyclophosphamide for 8 weeks complete remission was achieved. There was no relapse of the disease during the 2-month follow-up.

This report demonstrates the useful role of cyclophosphamide in the treatment of steroid-resistant nephrotic syndrome due to FSGS with glomerular tip lesion. A causal relationship between the insect bite and the nephrotic syndrome is suggested and an immune response could be responsible for the nephrotic syndrome.