Hyperchylomicronemia
Overview
* Triglycerides (TG) are fat (lipid) molecules that are made in the body from other sources such as carbohydrates, or are derived from food. Once TGs are absorbed through the intestines or made in the liver, they are carried via lipoproteins (carrier molecules) to tissues for use as fuel, and to fat cells (adipose tissue) for storage and later use, when energy is needed between meals. * High levels of TGs in the blood create a condition referred to as hypertriglyceridemia. Elevated levels of TGs can slow the flow of blood, and is now recognized as independent risk factor for heart disease -- the number one killer of people in the United States. * There are various types and subtypes of hypertriglyceridemia (I-V) based on the cause, lipid type, and clinical presentation of associated disorders. For example, type IV is associated with high VLDL, a major lipoprotein carrier that transports triglycerides across cell membranes and throughout the body.
Symptoms
* There are often no symptoms if the levels are below 1000mg/dl. Normal TG levels are 150mg/dl and lower. * There may be symptoms of atherosclerosis such as angina or heart attack. However, these occur after years of hyperTGs. * Inflammation of the Pancreas (pancreatitis) and abdominal pain, nausea, vomiting, back pain, mild jaundice, and back pain. This occurs if TGs are greater than 1000mg/dl. * If TG levels are greater than 2000 mg/dl, there may be headache, dizziness, enlarged liver, fatty skin lesions (Xanthomas), and shortness of breath. This is often referred to as chylomicronemia syndrome.
Causes
* Primary -- hereditary causes (i.e., inherited from parents via genes) * Secondary causes are more common -- liver disease, kidney diseases (e.g., Nephrotic Syndrome, uremia), thyroid disease (e.g., Hypothyroidism), excess caloric intake as in obesity, Diabetes Mellitus, glycogen storage disease type II, Cushing's Syndrome, certain immunoglobulin deficiencies, drugs (alcohol, estrogen, beta blockers, retinoids, corticosteroids, bile acid sequestrants, thiazide diuretics, etc.).
Diagnosis
* Is made after symptoms develop (as with pancreatitis or heart attack) or on routine blood check. Any patient with cholesterol levels greater than 240mg/dl will have his TGs measured. Any patients with atherosclerosis will also have their TGs measured. * With high levels of TG, blood serum may appear milky and thick upon direct visualization. * The doctor may see fatty deposits in the retina (lipemia retinalis), fatty skin deposits, or nodules (xanthomas) on clinical exam. * Fasting blood tests for Lipids and lipid fractions (cholesterol, HDL, LDL, triglycerides, IDL) and apoprotein B (those with high levels of this are at increased risk for coronary heart disease) are often done. *Genetic studies may be done in primary cases.