Acute nephritic syndrome is a group of disorders that cause inflammation of the internal kidney structures (specifically, the glomeruli).

Acute nephritic syndrome is often caused by an immune response triggered by an infection or other disease.

Causes seen more frequently in children and adolescents include the following:

• IgA nephropathy
• Henoch-Schonlein purpura
• Hemolytic uremic syndrome
• Post-streptococcal glomerulonephritis

Associated diseases seen more frequently in adults include:

• Abdominal abscesses
• Infective endocarditis
• Klebsiella pneumonia
• Goodpasture syndrome
• Hepatitis
• Membranoproliferative GN I
• Membranoproliferative GN II
• Rapidly progressive (crescentic) glomerulonephritis
• SLE or lupus nephritis
• Syphilis and other sexually transmitted diseases
• Typhoid fever
• Vasculitis
• Viral diseases such as mononucleosis, measles, mumps

The inflammation disrupts the functioning of the glomerulus, which is the part of the kidney that controls filtering and excretion. This disruption results in blood and protein appearing in the urine, and the build up of excess fluid in the body. Swelling results when protein is lost from the blood stream. (Protein maintains fluid within the blood vessels, and when it is lost the fluid collects in the tissues of the body). Blood loss from the damaged kidney structures leads to blood in the urine.

Acute nephritic syndrome may be associated with the development of high blood pressure, inflammation of the spaces between the cells of the kidney tissue, and acute kidney failure.

• Blood in the urine (urine appears dark, tea colored, or cloudy)
• Blurred vision
• Decreased urine volume (little or no urine may be produced)
• General aches and pains ( joint pain, muscle aches)
• General ill feeling (malaise)
• Headache
• Slow, sluggish, lethargic movement
• Swelling of the face, eye socket, legs, arms, hands, feet, abdomen, or other areas

Late symptoms include the following:

• Cough containing mucus or pink, frothy material coughed up
• Decreased alertness, drowsiness, confusion
• Difficulty breathing, especially at night, while lying down, or from exercise
• Easy bruising or bleeding
• Flank pain
• High blood pressure
• Nausea and vomiting
• Seizures

Your blood pressure may be high. When examining your abdomen, your health care provider may find signs of fluid overload and an enlarged liver. When listening to your lungs and chest with a stethoscope, abnormal heart and lung sounds may be heard. The neck veins may be enlarged from increased pressure.

Generalized swelling is often present. There may be signs of acute kidney failure.

Tests that may be done include:

• BUN
• Creatinine
• Creatinine clearance
• Urinalysis
• Urine appearance and color
• Potassium test
• Protein in the urine

A kidney biopsy reveals inflammation of the glomeruli, which may indicate the cause.

Tests to determine the cause of the acute nephritic syndrome may include:

• ANA titer (lupus)
• ANCA (antineutrophil cytoplasmic antibody for vasculitis)
• Anti-glomerular basement membrane antibody
• Blood culture
• Culture of the throat or skin
• Serum complement (C3 and C4)

The goal of treatment is to reduce the inflammation. Hospitalization is required for diagnosis and treatment of many forms of acute nephritic syndrome. The cause must be identified and treated. This may include antibiotics or other medications or treatment.

Bedrest may be recommended. The diet may include restriction of salt, fluids, and potassium. Medications to control high blood pressure may be prescribed. Corticosteroids or other anti-inflammatory medications may be used to reduce inflammation.

Other treatment of acute kidney failure may be appropriate.

For information and support, see kidney disease support groups.

The outlook depends on the disease responsible for the nephritis. When improvement occurs, symptoms associated with fluid retention (such as swelling and cough) and high blood pressure may go away in 1 or 2 weeks. However, urine tests take months to return to normal.

Children tend to do better than adults and usually recover completely. Only rarely do they develop complications or progress to chronic glomerulonephritis.

Adults do not recover quite as well or as rapidly as children. Although recurrence is unusual, at least one-third of adults whose acute nephritic syndrome recurs will eventually develop end-stage kidney disease.

• Acute kidney failure
• Chronic kidney failure
• End-stage kidney disease
• High blood pressure
• Congestive heart failure
• Pulmonary edema
• Chronic glomerulonephritis
• Nephrotic syndrome

Call your health care provider if you have symptoms of acute nephritic syndrome.

Many times the disorder cannot be prevented, although treatment of illness and infection may help to reduce the risk.