Hyponatraemia Health Dictionary

Ecstasy refers to a morbid mental condition, associated with an extreme sense of wellbeing, with a feeling of rapture, and temporary loss of self-control. It often presents as a form of religious obsession, with a feeling of direct communication with God, saintly voices and images being perceived. In milder cases the patient may preach as though with a divine mission to help others. Ecstasy may occur in happiness PSYCHOSIS, SCHIZOPHRENIA, certain forms of EPILEPSY, and abnormal personalities.

The term is also a street drug name for an amphetamine derivative, 3, 4-methylenedioxymethamphetamine or MDMA, increasingly used as a ‘recreational’ drug. It is classi?ed as a class A drug under the Misuse of Drugs Act 1971. MDMA is structurally similar to endogenous CATECHOLAMINES and produces central and peripheral sympathetic stimulation of alpha and beta ADRENERGIC RECEPTORS. It is taken into nerve terminals by the serotonin transporter and causes release of the NEUROTRANSMITTER substances serotonin and dopamine. Following this, SEROTONIN depletion is prolonged. As serotonin plays a major part in mood control, this leads to the characteristic ‘midweek depression’ experienced by MDMA users.

Several fatalities in young people have been attributed to adverse reactions resulting from MDMA use/abuse and possibly accompanying alcohol consumption. The principal effects are increase in pulse, blood pressure, temperature and respiratory rate. Additional complications such as cardiac ARRHYTHMIA, heatstroke-type syndrome, HYPONATRAEMIA and brain haemorrhage may occur. There is also concern over possible effects on the mental concentration and memory of those using ecstasy.

Management of patients who get to hospital is largely symptomatic and supportive but may include gastric decontamination, and use of DIAZEPAM as the ?rst line of treatment as it reduces central stimulation which may also reduce TACHYCARDIA, HYPERTENSION and PYREXIA.... ecstasy

These oral agents reduce the excessive amounts of GLUCOSE in the blood (HYPERGLYCAEMIA) in people with type 2 (INSULIN-resistant) diabetes (see DIABETES MELLITUS). Although the various drugs act di?erently, most depend on a supply of endogenous (secreted by the PANCREAS) insulin. Thus they are of no value in treating patients with type 1 diabetes (insulin-dependent diabetes mellitus (IDDM), in which the pancreas produces little or no insulin and the patient’s condition is stabilised using insulin injections). The traditional oral hypoglycaemic drugs have been the sulphonylureas and biguanides; new agents are now available – for example, thiazolidine-diones (insulin-enhancing agents) and alpha-glucosidase inhibitors, which delay the digestion of CARBOHYDRATE and the absorption of glucose. Hypoglycaemic agents should not be prescribed until diabetic patients have been shown not to respond adequately to at least three months’ restriction of energy and carbohydrate intake.

Sulphonylureas The main group of hypoglycaemic agents, these act on the beta cells to stimulate insulin release; consequently they are e?ective only when there is some residual pancreatic beta-cell activity (see INSULIN). They also act on peripheral tissues to increase sensitivity, although this is less important. All sulphonylureas may lead to HYPOGLYCAEMIA four hours or more after food, but this is relatively uncommon, and usually an indication of overdose.

There are several di?erent sulphonylureas; apart from some di?erences in their duration or action (and hence in their suitability for individual patients) there is little di?erence in their e?ectiveness. Only chlorpropamide has appreciably more side-effects – mainly because of its prolonged duration of action and consequent risk of hypoglycaemia. There is also the common and unpleasant chlorpropamide/ alcohol-?ush phenomenon when the patient takes alcohol. Selection of an individual sulphonylurea depends on the patient’s age and renal function, and often just on personal preference. Elderly patients are particularly prone to the risks of hypoglycaemia when long-acting drugs are used. In these patients chlorpropamide, and preferably glibenclamide, should be avoided and replaced by others such as gliclazide or tolbutamide.

These drugs may cause weight gain and are indicated only if poor control persists despite adequate attempts at dieting. They should not be used during breast feeding, and caution is necessary in the elderly and in those with renal or hepatic insu?ciency. They should also be avoided in porphyria (see PORPHYRIAS). During surgery and intercurrent illness (such as myocardial infarction, COMA, infection and trauma), insulin therapy should be temporarily substituted. Insulin is generally used during pregnancy and should be used in the presence of ketoacidosis.

Side-effects Chie?y gastrointestinal disturbances and headache; these are generally mild and infrequent. After drinking alcohol, chlorpropamide may cause facial ?ushing. It also may enhance the action of antidiuretic hormone (see VASOPRESSIN), very rarely causing HYPONATRAEMIA.

Sensitivity reactions are very rare, usually occurring in the ?rst six to eight weeks of therapy. They include transient rashes which rarely progress to erythema multiforme (see under ERYTHEMA) and exfoliate DERMATITIS, fever and jaundice; chlorpropamide may also occasionally result in photosensitivity. Rare blood disorders include THROMBOCYTOPENIA, AGRANULOCYTOSIS and aplastic ANAEMIA.

Biguanides Metformin, the only available member of this group, acts by reducing GLUCONEOGENESIS and by increasing peripheral utilisation of glucose. It can act only if there is some residual insulin activity, hence it is only of value in the treatment of non-insulin dependent (type 2) diabetics. It may be used alone or with a sulphonylurea, and is indicated when strict dieting and sulphonylurea treatment have failed to control the diabetes. It is particularly valuable in overweight patients, in whom it may be used ?rst. Metformin has several advantages: hypoglycaemia is not usually a problem; weight gain is uncommon; and plasma insulin levels are lowered. Gastrointestinal side-effects are initially common and persistent in some patients, especially when high doses are being taken. Lactic acidosis is a rarely seen hazard occurring in patients with renal impairment, in whom metformin should not be used.

Other antidiabetics Acarbose is an inhibitor of intestinal alpha glucosidases (enzymes that process GLUCOSIDES), delaying the digestion of starch and sucrose, and hence the increase in blood glucose concentrations after a meal containing carbohydrate. It has been introduced for the treatment of type 2 patients inadequately controlled by diet or diet with oral hypoglycaemics.

Guar gum, if taken in adequate doses, acts by delaying carbohydrate absorption, and therefore reducing the postprandial blood glucose levels. It is also used to relieve symptoms of the DUMPING SYNDROME.... hypoglycaemic agents

acute paralysis, dysphagia, and dysarthria resulting from damage to the myelin sheaths of nerve cells in the brainstem. It occurs most commonly as a complication of rapid correction of severe hyponatraemia (low serum sodium).... central pontine myelinolysis

a hormone produced by cells that do not usually produce it. Some tumour cells secrete hormones; for example, small-cell lung cancer cells secrete antidiuretic hormone and cause *hyponatraemia.... ectopic hormone

a life-threatening condition due to severe *hypothyroidism, which is often precipitated by an acute event, such as surgery, prolonged exposure to cold, infection, trauma, other severe illness, or sedative drugs. It manifests as hypothermia, slowing of the heart rate with a reduction in blood pressure and sometimes heart failure, pleural and peritoneal effusions, urinary retention, and a gradually reduced conscious state resulting in coma. Blood tests show hypothyroidism, *hyponatraemia, hypercholesterolaemia, retention of carbon dioxide, and anaemia. Treatment is with intravenous *thyroxine at a high dosage until the patient wakes up, when tablets can be administered. Support on a ventilator and intravenous fluids may be needed. Active slow rewarming should be undertaken.... myxoedema coma

(SIADH) a condition of inappropriately high plasma levels of ADH (see vasopressin) with associated water retention, dilutional *hyponatraemia, and the production of highly concentrated urine. Renal, adrenal, thyroid, and hepatic function are normal, as is the volume of circulating blood (euvolaemia). It is caused by a variety of pathological conditions, usually intrathoracic and intracerebral, and also by a number of drugs, including antidepressants, chemotherapy agents, and some of the older antidiabetic agents. The treatment involves fluid restriction, treatment (or removal) of the underlying cause (or drug), and, in severe cases, administration of *demeclocycline to reduce the effects of ADH on the kidney. Very rarely, hypertonic saline is given.... syndrome of inappropriate secretion of antidiuretic hormone