Definition of Membranoproliferative GN I:

Membranoproliferative glomerulonephritis type I is a kidney disorder that results in disrupted kidney function, caused by inflammation and changes in the microscopic structure of kidney cells.

See also: Membranoproliferative GN II

Causes, incidence, and risk factors:

Glomerulonephritis is inflammation of the glomeruli, the inner structures of the kidney that help filter waste and fluids from the blood to form urine.

Membranoproliferative GN I is a form of glomerulonephritis. It is caused by an abnormal immune response. Deposits of antibodies build up in a part of the kidneys called the glomerular basement membrane. This membrane helps filter waste and extra fluid from the blood.

The changes in this membrane lead disrupt the body's ability to filter urine. Protein and fluid leak out of the blood vessels into body tissues, leading to edema. Nitrogen waste products may accumulate in the blood (azotemia) because of poor kidney functioning.

The disorder is often progressive and eventually results in chronic renal failure.

Most cases of membranoproliferative glomerulonephritis are type I. The conditions affects both men and women, mostly people under age 30.

Symptoms:

• Blood in the urine
• Dark urine (smoke, cola, or tea colored)
• Cloudy urine
• Decrease in urine volume
• Swelling of any part of the body
• Changes in mental status such as decreased alertness or decreased concentration

Signs and tests:

The results of a physical examination vary depending on the symptoms. Swelling may be present along with signs of fluid overload, such as abnormal sounds when listening to the heart and lungs with a stethoscope.

Blood pressure is often high because of increased water and sodium (salt) retention and and increased production of renin, a hormone that controls blood pressure.

Membranoproliferative GN I may present in several forms. It may be seen as acute nephritic syndrome, nephrotic syndrome, or an abnormal urinalysis without symptoms.

These tests help confirm the diagnosis:

• Urinalysis
• Urine protein
• BUN and creatinine
• Serum complement levels
• Serum complement C3 nephritic factor

A kidney biopsy confirms the diagnosis of membranoproliferative GN I.

Treatment:

Treatment may vary according to the symptoms. The goals of treatment are to reduce syjmptoms, prevent complications, and slow the progression of the disorder.

Medicines that may be prescribed include

• Blood pressure medicines
• Cytotoxic agents
• Dipyridamole with or without aspirin
• Diuretics
• Steroids

A change in diet may be needed. This may include limiting salt, fluids, or protein.

Dialysis or kidney transplant may eventually be required to manage kidney failure.

Expectations (prognosis):

The disorder progresses slowly to chronic renal failure. Fifty percent of cases will develop chronic renal failure within 10 years.

Complications:

• Acute renal failure
• Acute nephritic syndrome
• Nephrotic syndrome
• Chronic renal failure

Calling your health care provider:

Call for an appointment with your health care provider if symptoms indicate MPGN I may be present.

Call for an appointment with your health care provider if symptoms worsen or persist, or if new symptoms develop, including decreased urine output.

Prevention:

Prevention is often not possible.