Atlas of pathophysiology, 2 Edition

Part II - Disorders

Gastrointestinal Disorders

Hyperlipidemia

Hyperlipidemia, also called hyperlipoproteinemia or lipid disorder, occurs when excess cholesterol, triglycerides, and lipoproteins are present in the blood. The primary form includes at least five distinct and inherited metabolic disorders. Hyperlipidemia may also occur secondary to other conditions such as diabetes mellitus. It's an important risk factor in developing atherosclerosis and heart disease.

Causes

Primary hyperlipoproteinemia

·   Types I and III transmitted as autosomal recessive traits

·   Types II, IV, and V transmitted as autosomal dominant traits

Secondary hyperlipoproteinemia

·   Diabetes mellitus

·   Pancreatitis

·   Hypothyroidism

·   Renal disease

·   Dietary fat intake greater than 40% of total calories; saturated fat intake greater than 10% of total calories; cholesterol intake greater than 300 mg/day

·   Habitual excessive alcohol use

·   Obesity

Pathophysiology

Lipids help in the production of energy, maintenance of body temperature, synthesis and repair of cell membranes, and production of steroid hormones. When lipid levels exceed what the body requires, the excess lipids form occlusive atherosclerotic plaques in blood vessels. These plaques obstruct normal blood flow, contribute to hypertension, slow or decrease the transport of oxygen to the heart and other body organs, and increase the risk of coronary heart disease.

Signs and symptoms

Type I

·   Recurrent attacks of severe abdominal pain, usually preceded by fat intake

·   Malaise and anorexia

·   Papular or eruptive xanthomas over pressure points and extensor surfaces

·   Ophthalmoscopic examination revealing lipemia retinalis (reddish white retinal vessels)

·   Abdominal spasm, rigidity, or rebound tenderness

·   Hepatosplenomegaly, with liver or spleen tenderness

·   Fever may be present

Type II

·   History of premature and accelerated coronary atherosclerosis

·   Tendinous xanthomas on the Achilles' tendon and tendons of the hands and feet

·   Tuberous xanthomas, xanthelasma

·   Juvenile corneal arcus

Age Alert

Symptoms of hyperlipidemia typically develop in people ages 20 to 30.

Type III

·   Tuberoeruptive xanthomas over elbows and knees

·   Palmar xanthomas on the hands, particularly the fingertips

Type IV

·   Obesity

·   Xanthomas may be noted during exacerbations

Type V

·   Abdominal pain associated with pancreatitis

·   Complaints related to peripheral neuropathy

·   Eruptive xanthomas on extensor surface of arms and legs

·   Ophthalmoscopic examination revealing lipemia retinalis

·   Hepatosplenomegaly

Diagnostic test results

·   Serum lipid profiles show elevated levels of total cholesterol, triglycerides, very low-density lipoproteins, low-density lipoproteins, or high-density lipoproteins.

Treatment

·   Weight reduction

·   Smoking cessation

·   Treatment of hypertension

·   Avoidance of hormonal contraceptives containing estrogen

·   Restriction of cholesterol and saturated animal fat intake

·   Avoidance of alcohol

·   Diet high in polyunsaturated fats

·   Exercise and physical fitness program

·   Statins, bile acid resins, cholesterol absorption inhibitors, fibrates, or nicotinic acid

·   Surgical creation of an ileal bypass

·   Portacaval shunt

P.191

UNDERSTANDING HYPERLIPIDEMIA

image

image