Familial hyperlipoproteinemia type 4
Overview
Familial hyperlipoproteinemia type 4: A familial condition where even a normal diet can result in blood lipid abnormalities.
Symptoms
* Increased very low density lipoproteins * Increased triglycerides * Early atherosclerosis * Abnormal glucose tolerance * Increased risk of ischemic heart disease
Treatment
The first goal is to identify and treat any underlying problem such as diabetes. If no underlying problem exists, the primary treatment of Types II, III, and IV is dietary management, especially restriction of cholesterol intake, possibly supplemented by drug therapy (cholestyramine, clofibrate, niacin) to lower plasma triglyceride or cholesterol level when diet alone is ineffective. Type I hyperlipoproteinemia requires long-term weight reduction, with fat intake restricted to less than 20 g/day. A 20- to 40-g/day medium-chain triglyceride diet may be ordered to supplement calorie intake. The patient should also avoid alcoholic beverages, to decrease plasma triglyceride levels. The prognosis is good with treatment; without treatment, death can result from pancreatitis. For Type II, dietary management to restore normal lipid levels and decrease the risk of atherosclerosis includes restriction of cholesterol intake to less than 300 mg/ day for adults and less than 150 mg/day for children; triglycerides must be restricted to less than 100 mg/day for children and adults. Diet should also be high in polyunsaturated fats. In familial hypercholesterolemia, nicotinic acid with a bile acid usually normalizes low-density lipoprotein levels. For severely affected children, a portacaval shunt is a last resort to reduce plasma cholesterol levels. The prognosis remains poor regardless of treatment; in homozygotes, myocardial infarction usually causes death before age 30. For Type III, dietary management includes restriction of cholesterol intake to less than 300 mg/day; carbohydrates must also be restricted, while polyunsaturated fats are increased. Clofibrate and niacin help lower blood lipid levels. Weight reduction is helpful. With strict adherence to prescribed diet, the prognosis is good. For Type IV, weight reduction may normalize blood lipid levels without additional treatment. Long-term dietary management includes restricted cholesterol intake, increased polyunsaturated fats, and avoidance of alcoholic beverages. Clofibrate and niacin may lower plasma lipid levels. The prognosis remains uncertain, however, because of predisposition to premature coronary artery disease. The most effective treatment for Type V is weight reduction and long-term maintenance of a low-fat diet. Alcoholic beverages must be avoided. Niacin, clofibrate, gemfibrozil, and a 20- to 40-g/day medium-chain triglyceride diet may prove helpful. The prognosis is uncertain because of the risk of pancreatitis. Increased fat intake may cause recurrent bouts of illness, possibly leading to pseudocyst formation, hemorrhage, and death.