Renal biopsy in nephrotic syndrome

Renal biopsy may be diagnostic in a patient with the nephrotic syndrome:

In adults renal biopsy is performed unless:

• there is a history of diabetes mellitus with progressive renal impairment
• the patient is taking a drug known to cause nephrotic syndrome

In cases of drug-induced nephrotic syndrome the drug is withdrawn; a biopsy is performed only if the patient fails to improve.

Because more than 75% of cases of paediatric nephrotic syndrome are caused by minimal change disease, children are given a trial of steroids unless there are features suggestive of another cause such as:

• persistent microscopic haematuria
• persistent diastolic hypertension
• low serum C3 levels
• a poorly selective differential protein loss