Acute nephritis

Acute nephritis is a sudden inflammatory kidney condition, usually glomerulonephritis, in which the glomeruli that filter blood become inflamed and filter less effectively. Glomerular disease affects both sexes and all ages, and a family history raises risk; the post-streptococcal form most often follows throat or skin infection in school-age children. Causes include immune system attack, lupus, vasculitis, infections such as hepatitis B, hepatitis C and HIV, endocarditis, some cancers and certain medicines; occasionally none is found. Mild cases may cause no symptoms, while others bring dark, frothy or blood-stained urine, swelling, high blood pressure, joint pain, tiredness and reduced urine output. Severe cases can progress to nephrotic syndrome, chronic kidney disease or kidney failure. Blood and urine tests assess the problem, and ultrasound or kidney biopsy may follow. Treatment targets the cause: dietary salt reduction, blood pressure medicines such as ACE inhibitors, and immunosuppressants for immune-mediated disease.

Seek urgent care for fever with flank pain, inability to pass urine, or blood in the urine. See a doctor for burning on urination that lasts more than two days, urinary symptoms that keep returning, or any change in urinary flow in men over 50. Call the local emergency number for any symptom that is sudden and severe. This page is a reference for healthcare professionals and does not replace an assessment.