A structure or process that is not normal (typical, usual or conforming to the standard); di?ering from the usual condition of the body.
Autosomal abnormalities cause physical and mental defects of varying severity. Some types of autosomal abnormality, known as trisomy, consist of an extra chromosome on 1 of the 22 pairs of autosomes. The most common trisomy is Down’s syndrome. Sometimes, part of a chromosome is missing, as in cri du chat syndrome. In translocation, a part of a chromosome is joined to another, causing no ill effects in the person but a risk of abnormality in his or her children.
Sex chromosome abnormalities include Turner’s syndrome, in which a girl is born with a single X chromosome in her
cells instead of 2, causing physical abnormalities, defective sexual development, and infertility. A boy with 1 or more extra X chromosomes has Klinefelter’s syndrome, which causes defective sexual development and infertility. The presence of an extra X chromosome in women or an extra Y chromosome in men normally has no physical effect but increases the risk of mild mental handicap.
Chromosomal abnormalities are diagnosed by chromosome analysis in early pregnancy, using amniocentesis or chorionic villus sampling.... chromosomal abnormalities
Diarrhoea may be due simply to anxiety or may be caused by an intestinal infection (see gastroenteritis); by an intestinal disorder such as ulcerative colitis or Crohn’s disease; or by irritable bowel syndrome. Loose stools may indicate malabsorption. Constipation is generally harmless but, if it develops unexpectedly, may be caused by a large-intestine disorder such as colon cancer.
Pale faeces may be caused by diarrhoea, a lack of bile in the intestine as a result of bile duct obstruction, or a disease that causes malabsorption (such as coeliac disease). Such faeces may be oily, foul-smelling, and difficult to flush away. Dark faeces may result from taking iron tablets. However, if faeces are black, there may be bleeding in the upper digestive tract.
Faeces containing excessive mucus are sometimes associated with constipation or irritable bowel syndrome. Enteritis, dysentery, or a tumour of the intestine (see intestine, tumours of) may result in excess mucus, which is often accompanied by blood.
Blood in the faeces differs in appearance depending on the site of bleeding. Bleeding from the stomach or duodenum is usually passed in the form of black, tarry faeces. Blood from the colon is red and is usually passed at the same time as the faeces. Bleeding from the rectum or anus, which may be due to tumours or to haemorrhoids, is usually bright red. (See also rectal bleeding.)... faeces, abnormal
Numbness and pins-and-needles are common abnormal sensations. The special senses can be impaired by damage to the relevant sensory apparatus (see vision, disorders of; smell; deafness; tinnitus). Other causes of abnormal sensation include peripheral nerve damage caused by diabetes mellitus, herpes zoster infection, or pressure from a tumour, and disruption of nerve pathways in the brain or spinal cord due to spinal injury, head injury, stroke, and multiple sclerosis.
Pressure on or damage to nerves can sometimes be relieved by surgery or by treatments for the cause.
In other cases, distressing abnormal sensation can be relieved only by cutting the relevant nerve fibres or by giving injections to block the transmission of signals.... sensation, abnormal
Conditions of abnormal production of urine include excessive production (see urination, excessive), oliguria, and anuria. Abnormal appearances of urine include cloudiness (which may be caused by a urinary tract infection, a calculus, or the presence of salts); haematuria; discoloration from certain foods or drugs; and frothiness (which may be caused by an excess of protein).
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