Membranoproliferative GN

Definition

Membranoproliferative glomerulonephritis is a kidney disorder that involves inflammation and changes in the microscopic structure of kidney cells. It leads to disrupted kidney function.

Alternative Names

Membranoproliferative GN I; Membranoproliferative GN II; Mesangiocapillary glomerulonephritis; Membranoproliferative glomerulonephritis; Lobular GN; Glomerulonephritis - membranoproliferative; MPGN type I; MPGN type 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 is a form of glomerulonephritis 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 swelling (edema). Nitrogen waste products may build up in the blood (azotemia) because of poor kidney functioning.

There are two forms of membranoproliferative GN:

• Membranoproliferative GN I
• Membranoproliferative GN II

Most cases are type I. Membranoproliferative GN II is much less common than Membranoproliferative GN I. It also tends to get worse faster than membranoproliferative GN I.

The conditions affect both men and women, mostly 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 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 depends on the symptoms. The goals of treatment are to reduce symptoms, prevent complications, and slow the progression of the disorder.

A change in diet may be needed. This may include limiting salt, fluids, or protein to help control high blood pressure, swelling, and the build up of waste products in the blood.

Medicines that may be prescribed include:

• Blood pressure medications
• Cytotoxic medications
• Dipyridamole with or without aspirin
• Diuretics
• Steroids

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

Expectations (prognosis)

The disorder often slowly gets worse and eventually results in chronic kidney failure. Fifty percent of cases lead to 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 you have symptoms of this condition. Also 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.

References

In: Brenner BM, ed. Brenner: Brenner and Rector's the Kidney. 8th ed. Philadelphia, Pa: Saunders Elsevier; 2007:chap 30.