Nephritis

Nephritis is inflammation of the kidney. The term is used as an umbrella for several conditions in which inflammatory processes affect renal tissue. The main categories are glomerulonephritis, interstitial nephritis, and pyelonephritis.

Glomerulonephritis involves inflammation of the glomeruli and can be immune-mediated, postinfectious, or associated with systemic diseases such as lupus. Interstitial nephritis affects the interstitium and tubules and is often drug-induced, but can also accompany infections or autoimmune conditions. Pyelonephritis refers to infection of the kidney pelvis and parenchyma, typically caused by bacteria that ascend from the urinary tract.

Symptoms range from asymptomatic to signs of kidney dysfunction. Common features include hematuria (blood in urine), proteinuria, edema, and hypertension; flank or abdominal pain may be present in glomerulonephritis or pyelonephritis. Fever and malaise can occur with infectious causes. Diagnosis relies on urinalysis and blood tests, including creatinine and electrolyte levels, along with imaging studies. A kidney biopsy may be needed to determine the exact type of nephritis and guide treatment in some cases.

Treatment depends on the cause and severity. Infections require antibiotics; immune-mediated forms may require corticosteroids or other immunosuppressants. Stopping offending drugs is essential in drug-induced interstitial nephritis. Management often includes controlling blood pressure, reducing edema, and supporting kidney function; dialysis may be necessary in advanced kidney failure.

Prognosis varies widely. Some forms resolve with treatment, while others cause ongoing kidney damage and chronic kidney disease. Prevention focuses on avoiding nephrotoxins, prompt treatment of infections, and regular monitoring in at-risk individuals.