Known colloquially as ‘mad cow disease’, this is a fatal and untreatable disease. Along with scrapie in sheep and CREUTZFELDT-JACOB DISEASE (CJD) in humans, BSE belongs to a class of unusual degenerative diseases of the brain known as transmissible spongiform encephalopathies. The disease is caused by abnormal PRION proteins, which are resistant to cellular degradation. These abnormal prion proteins accumulate in and eventually cause the death of nerve cells, both in the spinal cord and the brain. The rare human disease CJD occurs throughout the world and is of three types: sporadic, iatrogenic (see IATROGENIC DISEASE) and inherited.
Since the BSE epidemic in cattle developed in the UK in the 1980s, however, a new variant of CJD has been identi?ed and is believed to be the result of consumption of the meat of BSE-infected cattle. Studies in transgenic mice have con?rmed that BSE caused variant CJD. The new variant has affected younger people and may have a shorter incubation period. If this incubation period turns out to be the same as for the other types of CJD, however, it could be 2005– 2010 before the peak of this outbreak is reached. Over 148 people had died, or were dying, from variant CJD in the UK by the year 2005.
The appearance of BSE in cattle is believed to have been caused by a gene mutation (see GENETIC DISORDERS), although whether this mutation ?rst occurred in cattle or in some other animal remains uncertain. Although the ?rst case of BSE was o?cially reported in 1985, the ?rst cattle are thought to have been infected in the 1970s. BSE spread to epidemic proportions because cattle were fed meat and bone meal, made from the o?al of cattle suffering from or incubating the disease. Mother-to-calf transfer is another likely route of transmission, although meat and bone meal in cattle feed were the main cause of the epidemic. The epidemic reached its peak in 1992 when the incidence of newly diagnosed cases in cattle was 37,545.
A two-year UK government inquiry into the BSE epidemic concluded that BSE had caused a ‘harrowing fatal disease in humans’, and criticised o?cials for misleading the public over the risk to humans from BSE. Consequently, a compensation package for patients and relatives was made available. Meanwhile, a ban on the export of UK beef and restrictions on the type of meat and products made from beef that can be sold to the public were put in place. Although initially thought to be a problem primarily con?ned to the UK, several other countries – notably France, Germany, Spain, Switzerland and the United States – have also discovered BSE in their cattle.
A neuropsychiatric syndrome caused by disease of the LIVER, and occurring most often in patients with CIRRHOSIS – see also LIVER, DISEASES OF; it also occurs in acute form in acute failure of liver function. The disorder is believed to be the result of biochemical disturbance of brain function, because the condition is reversible and pathological changes in brain tissue are rarely found. The patient’s intellect, personality, emotions and consciousness are altered but neurological signs may or may not be identi?ed. Apathy, confusion, drowsiness, sometimes CONVULSIONS, speech disturbance and eventually COMA mark the progress of the condition. The principles of treatment are to remove the precipitating causes. These include: URAEMIA; sedative, antidepressant and hypnotic drugs; gastrointestinal bleeding; too much protein in the diet; infection; and trauma (including surgical operations).... hepatic encephalopathy
A disease of the neurological system caused by a PRION. Spongy degeneration of the BRAIN occurs with progressive DEMENTIA. Known examples of the disorder in humans are CREUTZFELDT-JAKOB DISEASE (CJD) and KURU. Among animals, scrapie in sheep and BOVINE SPONGIFORM ENCEPHALOPATHY (BSE) are caused by slow viruses. The latter has occurred as an outbreak in cattle over the past decade or so, probably as a result of cattle being fed processed o?al from infected animals. Some people have developed a form of CJD from eating infected beef.... spongiform encephalopathy
A complication of severe HYPERTENSION, this serious but uncommon condition is characterised by neurological symptoms which include transient verbal and visual disturbances, PARAESTHESIA, disorientation, ?ts and sometimes loss of consciousness. It also affects the eyes, causing PAPILLOEDEMA. Haemorrhages may occur in the brain, usually in the area of the BASAL GANGLIA. Neurological symptoms can usually be treated e?ectively by controlling the patient’s hypertension.... hypertensive encephalopathy
(HIE, birth asphyxia, perinatal asphyxia) brain damage in a newborn infant as a result of the brain receiving inadequate oxygen. HIE may cause seizures and, if severe, death within minutes of oxygen deprivation. If the infant survives there can be significant long-term consequences, such as developmental delay, learning disabilities, or cerebral palsy.... hypoxic-ischaemic encephalopathy
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