An excess of fat in the blood, characterising a group of metabolic disorders. The two most important fats circulating in the blood are CHOLESTEROL and TRIGLYCERIDE. Raised blood levels of cholesterol predispose to ATHEROMA and coronary artery disease (see HEART, DISEASES OF); raised triglycerides predispose to pancreatitis (see PANCREAS, DISORDERS OF). Six types of hyperlipidaemia have been identi?ed, and diagnosis of the di?erent types depends upon blood tests to discover lipid levels. Some of the hyperlipidaemias are familial, and some are secondary to other diseases such as hypothyroidism (see THYROID GLAND, DISEASES OF), DIABETES MELLITUS, nephrotic syndrome and alcoholism.
Treatment There is evidence that therapy which lowers the lipid concentration reduces the progression of premature atheroma, particularly in those who suffer from the familial disorder. Treatment should include appropriate diets, usually food that is low in cholesterol and saturated fats. There are a number of drugs available for lowering the lipid content of the plasma, but these should be reserved for patients in whom severe hyperlipidaemia is inadequately controlled by weight reduction. Anion-exchange resins – clo?brate, beza?brate and gem?brozil, for example – and statins such as atorvastatin and simvastatin, as well as nicotinic acid, all lower plasma cholesterol and plasma triglyceride concentration through their e?ect on reducing the hepatic production of lipoproteins. Cholestyramine and colestipol, both of which are anion-exchange resins, bind bile salts in the gut and so decrease the absorption of the cholesterol that these bile salts contain – hence lowering plasma cholesterol concentrations. Probucol lowers plasma cholesterol concentrations by increasing the metabolism of low-density lipoproteins.
The statins (atorvastatin, cerivastatin, ?uvastatin, pravastatin and simvastatin) inhibit an enzyme involved in synthesising cholesterol, especially in the liver. They are more e?ective than anion-exchange resins in lowering LDL (low-density lipoprotein) cholesterol – a form of low-density cholesterol carried in the bloodstream, high levels of which are believed to be the main cause of atheroma. Statins are, however, less e?ective than the clo?brate group in reducing triglycerides and raising HDL (highdensity lipoprotein) cholesterol (high-density cholesterol).... hyperlipidaemia
An inherited condition that affects certain Sephardic Jewish, Armenian, and Arab families. Its cause is unknown. Symptoms usually begin between the ages of 5 and 15 years, and include recurrent episodes of fever, abdominal and chestpain, and arthritis. Red skin swellings sometimes occur, and affected people may also suffer psychiatric problems. Attacks usually last from 24–48 hours but may be longer. Between attacks there are usually no symptoms. Although there is no specific treatment for familial Mediterranean fever, known sufferers can reduce the incidence of attacks by taking colchicine. Death may eventually occur from amyloidosis, which is a complication of the condition.... familial mediterranean fever
Metabolic disorders that are characterized by high levels of lipids in the blood. Hyperlipidaemias may be inherited or associated with another disorder, such as hypothyroidism, diabetes mellitus, kidney failure, or Cushing’s syndrome. They may also be a result of use of corticosteroid drugs. Hyperlipidaemias are associated with atherosclerosis and coronary artery disease.The signs depend on the type of hyperlipidaemia and may include fatty nodules in the skin or over joints, and a white line around the rim of the cornea.
Diagnosis depends on blood tests.
Treatment aims to reduce blood lipid levels, usually by a low-fat diet and lipid-lowering drugs.... hyperlipidaemias
A rare, inherited disorder, also known as polyposis coli, in which many polyps are present throughout the gut, but mainly in the colon. If not treated, cancer of the colon (see colon, cancer of) is almost certain to develop. The polyps may appear from age 10. They may cause bleeding and diarrhoea; however, there are often no symptoms until cancer has developed. The polyps are detected by colonoscopy.
Since there is a 50 per cent chance that children of an affected person will inherit the disease, medical surveillance is necessary from around the age of 12.
Individual polyps may be cauterized (see cauterization).
The high risk of developing cancer often means that a colectomy and an ileostomy are performed.... polyposis, familial
an autosomal *dominant disorder due to a mutation in the gene for the *prion protein (PrP): it is an example of a *spongiform encephalopathy. Patients present with intractable progressive insomnia, disturbances of the autonomic nervous system, and eventually dementia.... fatal familial insomnia
a state of disordered mood that combines elements of *mania and *depression; it is a common feature of *bipolar affective disorder. Symptoms include overactivity, flight of ideas, depressed mood, and suicidal *ideation.... mixed affective state
a disease with features in common with systemic *lupus erythematosus, *polymyositis, and *scleroderma. It is characterized by high levels of antibodies to ribonucleoprotein and most commonly affects women between 20 and 40 years of age.... mixed connective tissue disease