Hyperlipoproteinemia
Marked by increased plasma concentrations of one or more lipoproteins, hyperlipoproteinemia affects lipid transport in serum. Primary hyperlipoproteinemia occurs
as at least five distinct metabolic disorders, all of which may be inherited. Hyperlipoproteinemia may also occur secondary to other conditions, such as diabetes mellitus. (See Classifying hyperlipoproteinemia.) The disorder produces varied clinical changes. These include relatively mild signs and symptoms that can be corrected by dietary management to potentially fatal pancreatitis.
as at least five distinct metabolic disorders, all of which may be inherited. Hyperlipoproteinemia may also occur secondary to other conditions, such as diabetes mellitus. (See Classifying hyperlipoproteinemia.) The disorder produces varied clinical changes. These include relatively mild signs and symptoms that can be corrected by dietary management to potentially fatal pancreatitis.
Causes
The primary hyperlipoproteinemias result from genetic disorders. Types I and III are transmitted as autosomal recessive traits; types II, IV, and V are transmitted as autosomal dominant traits. Secondary hyperlipoproteinemia results from another metabolic disorder, such as diabetes mellitus, consumption of alcohol, or ingestion of oral contraceptives.
Complications
Sequelae of hyperlipoproteinemia include coronary artery disease (CAD) and pancreatitis.
Assessment
The history of a patient with type I disease typically reveals recurrent attacks of severe abdominal pain similar to pancreatitis, usually preceded by fat intake. The patient may also report malaise and anorexia.
Inspection may reveal papular or eruptive xanthomas (pinkish yellow cutaneous deposits of fat) over pressure points and extensor surfaces. Ophthalmoscopic examination typically reveals lipemia retinalis (reddish white retinal vessels). Palpation may detect abdominal spasm, rigidity, or rebound tenderness, and hepatosplenomegaly, with liver or spleen tenderness. Fever may be present.
A patient with type II disease may have a history of premature and accelerated coronary atherosclerosis, with symptoms typically developing when the patient is in his 20s or 30s. Inspection commonly reveals tendinous xanthomas (firm masses) on the Achilles tendons and tendons of the hands and feet, tuberous xanthomas, xanthelasma, and juvenile corneal arcus (opaque ring surrounding the corneal periphery).
Typically, a patient with type III disease doesn’t complain of clinical symptoms until after age 20 when severe atherosclerosis may develop. The patient’s history may include such aggravating factors as obesity, hypothyroidism, and diabetes mellitus.
Inspection may reveal tuberoeruptive xanthomas (soft, inflamed, pedunculated lesions) over the elbows and knees and palmar xanthomas on the hands, particularly the fingertips (orange or yellow discolorations of the palmar and digital creases).
A patient with type IV disease may have a history of atherosclerosis and early CAD. Patient history may also include such factors as excessive alcohol consumption, poorly controlled diabetes mellitus, and ingestion of birth control pills containing estrogen, which can precipitate severe hypertriglyceridemia. Hypertension and hyperuricemia may also be present. Inspection commonly reveals the presence of obesity. Although not characteristic, xanthomas may be noted during exacerbations.
The history of a patient with type V disease may reveal abdominal pain associated with pancreatitis and complaints related to peripheral neuropathy. Inspection may note eruptive xanthomas on the extensor surface of the arms and legs. Ophthalmoscopic examination may reveal lipemia retinalis. Palpation may detect hepatosplenomegaly.
Diagnostic tests
Serum lipid profiles—elevated levels of total cholesterol, triglycerides, very–low–density lipoproteins (VLDL), low–density lipoproteins (LDL), or high–density lipoproteins (HDL)—indicate hyperlipoproteinemia.
Treatment
Primary treatment focuses on dietary management, including weight reduction, restriction of cholesterol and saturated animal fat intake, and inclusion of polyunsaturated vegetable oils, which reduce concentration of plasma LDL. Dietary fat
should account for no more than 30% of the total calorie intake.
should account for no more than 30% of the total calorie intake.
Classifying hyperlipoproteinemia
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