Malignant Nephrosclerosis

In malignant nephrosclerosis, severe high blood pressure (malignant hypertension) damages the smallest arteries in the kidneys, and kidney failure progresses rapidly.

Malignant nephrosclerosis occurs in about 1% of people with high blood pressure and is more common among blacks than whites. It is most common in men during their 40s and 50s and women during their 30s.

Malignant hypertension most commonly results from poorly controlled high blood pressure. It may also result from other conditions, such as glomerulonephritis, chronic kidney failure, narrowing of the renal artery (renal vascular hypertension), inflammation of renal blood vessels (vasculitis), or, rarely, hormonal disorders such as pheochromocytoma, Conn's syndrome, or Cushing's syndrome.

Symptoms and Diagnosis

Symptoms initially are caused by the effects of the severe high blood pressure on the brain and heart. Symptoms, which may include restlessness, blurred vision, headache, nausea, vomiting, sleepiness, and confusion, result from swelling of brain tissue. Seizures and coma may also occur if swelling is severe or if there is bleeding within the brain.

By viewing the back of the eye with an ophthalmoscope, a doctor can see areas of bleeding, collections of fluid, and swelling of the optic nerve. The doctor may also detect heart enlargement and heart failure.

Damage to the kidneys eventually produces the symptoms of kidney failure, such as fatigue and weakness. Protein leaking from the kidneys can be detected in the urine, along with blood cells. Anemia often results from the breakdown and impaired production of red blood cells. Widespread clotting within the blood vessels is also common (disseminated intravascular coagulation (see Section 14, Chapter 173)). Blood levels of substances produced by the kidneys that help regulate blood pressure (renin and aldosterone) are extremely high.

Prognosis and Treatment

If malignant nephrosclerosis is not treated, about 50% of people who have it die within 6 months, and most of the remainder die within a year. About 60% of the deaths result from kidney failure, 20% from heart failure, 19% from strokes, and 1% from heart attacks. Aggressive lowering of blood pressure with diet and drugs and treating the kidney failure significantly reduce the death rate.

People who have less severe kidney failure improve the most with treatment. Those who have progressive kidney failure can be maintained by dialysis and occasionally improve enough that dialysis can be discontinued.