Inversion Health Dictionary

Inversion: From 1 Different Sources


n. 1. the turning inwards or inside-out of a part or organ: commonly applied to the state of the uterus after childbirth when its upper part is pulled through the cervical canal. 2. a chromosome mutation in which a block of genes within a chromosome are in reverse order, due to that section of the chromosome becoming inverted. The centromere may be included in the inverted segment (pericentric inversion) or not (paracentric inversion).
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Breasts, Diseases Of

The female breasts may be expected to undergo hormone-controlled enlargement at puberty, and later in pregnancy, and the glandular part of the breast undergoes evolution (shrinkage) after the menopause. The breast can also be affected by many di?erent diseases, with common symptoms being pain, nipple discharge or retraction, and the formation of a lump within the breast.

Benign disease is much more common than cancer, particularly in young women, and includes acute in?ammation of the breast (mastitis); abscess formation; and benign breast lumps, which may be ?broadenosis – di?use lumpiness also called chronic mastitis or ?brocystic disease – in which one or more ?uid-?lled sacs (cysts) develop.

Women who are breast feeding are particularly prone to mastitis, as infection may enter the breast via the nipple. The process may be arrested before a breast abscess forms by prompt treatment with antibiotics. Non-bacterial in?ammation may result from mammary duct ectasia (dilatation), in which abnormal or

blocked ducts may over?ow. Initial treatments should be with antibiotics, but if an abscess does form it should be surgically drained.

Duct ectasia, with or without local mastitis, is the usual benign cause of various nipple complaints, with common symptoms being nipple retraction, discharge and skin change.

Breast lumps form the chief potential danger and may be either solid or cystic. Simple examination may fail to distinguish the two types, but aspiration of a benign cyst usually results in its disappearance. If the ?uid is bloodstained, or if a lump still remains, malignancy is possible, and all solid lumps need histological (tissue examination) or cytological (cell examination) assessment. As well as having their medical and family history taken, any women with a breast lump should undergo triple assessment: a combination of clinical examination, imaging

– mammography for the over-35s and ultrasonagraphy for the under-35s – and ?ne-needle aspiration. The medical history should include details of any previous lumps, family history (up to 10 per cent of breast cancer in western countries is due to genetic disposition), pain, nipple discharge, change in size related to menstrual cycle and parous state, and any drugs being taken by the patient. Breasts should be inspected with the arms up and down, noting position, size, consistency, mobility, ?xity, and local lymphadenopathy (glandular swelling). Nipples should be examined for the presence of inversion or discharge. Skin involvement (peau d’orange) should be noted, and, in particular, how long changes have been present. Fine-needle aspiration and cytological examination of the ?uid are essential with ULTRASOUND, MAMMOGRAPHY and possible BIOPSY being considered, depending on the patient’s age and the extent of clinical suspicion that cancer may be present.

The commonest solid benign lump is a ?broadenoma, particularly in women of childbearing age, and is a painless, mobile lump. If small, it is usually safe to leave it alone, provided that the patient is warned to seek medical advice if its size or character changes or if the lump becomes painful. Fibroadenosis (di?use lumpiness often in the upper, outer quadrant) is a common (benign) lump. Others include periductal mastitis, fat NECROSIS, GALACTOCELE, ABSCESS, and non-breast-tissue lumps – for example, a LIPOMA (fatty tissue) or SEBACEOUS CYST. A woman with breast discharge should have a mammograph, ductograph, or total duct excision until the cause of any underlying duct ectasia is known. Appropriate treatment should then be given.

Malignant disease most commonly – but not exclusively – occurs in post-menopausal women, classically presenting as a slowly growing, painless, ?rm lump. A bloodstained nipple discharge or eczematous skin change may also be suggestive of cancer.

The most commonly used classi?cation of invasive cancers has split them into two types, ductal and lobular, but this is no longer suitable. There are also weaknesses in the tumour node metastases (TNM) system and the International Union Against Cancer (UICC) classi?cation.

The TNM system – which classi?es the lump by size, ?xity and presence of affected axillary glands and wider metastatic spread – is best combined with a pathological classi?cation, when assessing the seriousness of a possibly cancerous lump. Risk factors for cancer include nulliparity (see NULLIPARA), ?rst pregnancy over the age of 30 years, early MENARCHE, late MENOPAUSE and positive family history. The danger should be considered in women who are not breast feeding or with previous breast cancer, and must be carefully excluded if the woman is taking any contraceptive steroids or is on hormone-replacement therapy (see under MENOPAUSE).

Screening programmes involving mammography are well established, the aim being to detect more tumours at an early and curable stage. Pick-up rate is ?ve per 1,000 healthy women over 50 years. Yearly two-view mammograms could reduce mortality by 40 per cent but may cause alarm because there are ten false positive mammograms for each true positive result. In premenopausal women, breasts are denser, making mammograms harder to interpret, and screening appears not to save lives. About a quarter of women with a palpable breast lump turn out to have cancer.

Treatment This remains controversial, and all options should be carefully discussed with the patient and, where appropriate, with her partner. Locally contained disease may be treated by local excision of the lump, but sampling of the glands of the armpit of the same side should be performed to check for additional spread of the disease, and hence the need for CHEMOTHERAPY or RADIOTHERAPY. Depending on the extent of spread, simple mastectomy or modi?ed radical mastectomy (which removes the lymph nodes draining the breast) may be required. Follow-up chemotherapy, for example, with TAMOXIFEN (an oestrogen antagonist), much improves survival (it saves 12 lives over 100 women treated), though it may occasionally cause endometrial carcinoma. Analysis in the mid-1990s of large-scale international studies of breast-cancer treatments showed wide variations in their e?ectiveness. As a result the NHS has encouraged hospitals to set up breast-treatment teams containing all the relevant health professional experts and to use those treatments shown to be most e?ective.

As well as the physical treatments provided, women with suspected or proven breast cancer should be o?ered psychological support because up to 30 per cent of affected women develop an anxiety state or depressive illness within a year of diagnosis. Problems over body image and sexual diffculties occur in and around one-quarter of patients. Breast conservation and reconstructive surgery can improve the physical effects of mastectomy, and women should be advised on the prostheses and specially designed brassieres that are available. Specialist nurses and self-help groups are invaluable in supporting affected women and their partners with the problems caused by breast cancer and its treatment. Breast Cancer Care, British Association of Cancer United Patients (BACUP), Cancerlink, and Cancer Relief Macmillan Fund are among voluntary organisations providing support.... breasts, diseases of

Claw-foot

Claw-foot, or PES CAVUS, is a familial deformity of the foot characterised by an abnormally high arch of the foot accompanied by shortening of the foot, clawing of the toes, and inversion, or turning inwards, of the foot and heel. Its main e?ect is to impair the resilience of the foot resulting in a sti? gait and aching pain. Milder cases are treated with special shoes ?tted with a sponge rubber insole. More severe cases may require surgical treatment.... claw-foot

Dextrocardia

A condition in which a person’s heart is situated on the right of the chest in a mirror image of its usual position. This may be associated with similar inversion of the abdominal organs – situs inversus.... dextrocardia

Sex Chromosomes

In humans there are 23 pairs of CHROMOSOMES. Male and female di?er in respect of one pair. In the nucleus of female cells, the two members of the pair are identical and are called X chromosomes. In the male nucleus there is one X chromosome paired with a dissimilar, di?erently sized chromosome called the Y chromosome. In the sex cells, after MEIOSIS, all cells in the female contain a single X chromosome. In the male, half will contain an X chromosome and half a Y chromosome. If a sperm with an X chromosome fertilises an ovum (which, as stated, must have an X chromosome) the o?spring will be female; if a sperm with a Y chromosome fertilises the ovum the o?spring will be male. It is the sex chromosomes which determine the sex of an individual.

Sometimes during cell division chromosomes may be lost or duplicated, or abnormalities in the structure of individual chromosomes may occur. The surprising fact is the infrequency of such errors. About one in 200 live-born babies has an abnormality of development caused by a chromosome, and two-thirds of these involve the sex chromosomes. There is little doubt that the frequency of these abnormalities in the early embryo is much higher, but because of the serious nature of the defect, early spontaneous ABORTION occurs.

Chromosome studies on such early abortions show that half have chromosome abnormalities, with errors of autosomes being three times as common as sex chromosome anomalies. Two of the most common abnormalities in such fetuses are triploidy with 69 chromosomes and trisomy of chromosome 16. These two anomalies almost always cause spontaneous abortion. Abnormalities of chromosome structure may arise because of:

Deletion Where a segment of a chromosome is lost.

Inversion Where a segment of a chromosome becomes detached and re-attached the other way around. GENES will then appear in the wrong order and thus will not correspond with their opposite numbers on homologous chromosomes.

Duplication Where a segment of a chromosome is included twice over. One chromosome will have too little nuclear material and one too much. The individual inheriting too little may be non-viable and the one with too much may be abnormal.

Translocation Where chromosomes of different pairs exchange segments.

Errors in division of centromere Sometimes the centromere divides transversely instead of longitudinally. If the centromere is not central, one of the daughter chromosomes will arise from the two short arms of the parent chromosome and the other from the two long arms. These abnormal daughter chromosomes are called isochromosomes.

These changes have important bearings on heredity, as the e?ect of a gene depends not only upon its nature but also upon its position on the chromosome with reference to other genes. Genes do not act in isolation but against the background of other genes. Each gene normally has its own position on the chromosome, and this corresponds precisely with the positon of its allele on the homologous chromosome of the pair. Each member of a pair of chromosomes will normally carry precisely the same number of genes in exactly the same order. Characteristic clinical syndromes, due to abnormalities of chromosome structure, are less constant than those due to loss or gain of a complete chromosome. This is because the degree of deletion, inversion and duplication is inconstant. However, translocation between chromosomes 15 and 21 of the parent is associated with a familial form of mongolism (see DOWN’S (DOWN) SYNDROME) in the o?spring, and deletion of part of an X chromosome may result in TURNER’S SYNDROME.

Non-disjunction Whilst alterations in the structure of chromosomes arise as a result of deletion or translocation, alterations in the number of chromosomes usually arise as a result of non-disjunction occurring during maturation of the parental gametes (germ cells). The two chromosomes of each pair (homologous chromosomes) may fail to come together at the beginning of meiosis and continue to lie free. If one chromosome then passes to each pole of the spindle, normal gametes may result; but if both chromosomes pass to one pole and neither to the other, two kinds of abnormal gametes will be produced. One kind of gamete will contain both chromosomes of the pair, and the other gamete will contain neither. Whilst this results in serious disease when the autosomes are involved, the loss or gain of sex chromosomes seems to be well tolerated. The loss of an autosome is incompatible with life and the malformation produced by a gain of an autosome is proportional to the size of the extra chromosome carried.

Only a few instances of a gain of an autosome are known. An additional chromosome 21 (one of the smallest autosomes) results in mongolism, and trisomy of chromosome 13 and 18 is associated with severe mental, skeletal and congenital cardiac defects. Diseases resulting from a gain of a sex chromosome are not as severe. A normal ovum contains 22 autosomes and an X sex chromosome. A normal sperm contains 22 autosomes and either an X or a Y sex chromosome. Thus, as a result of nondisjunction of the X chromosome at the ?rst meiotic division during the formation of female gametes, the ovum may contain two X chromosomes or none at all, whilst in the male the sperm may contain both X and Y chromosomes (XY) or none at all. (See also CHROMOSOMES; GENES.)... sex chromosomes

Nipple

The small prominence at the tip of each breast. Women’s nipples contain tiny openings through which milk can pass. The nipple and the areola, a surrounding area of dark skin, both increase in size during pregnancy. Involuntary muscle in the nipple allows it to become erect.

Structural defects of the nipple are rare. An inverted nipple is usually a harmless abnormality of development. Nipple inversion that develops in older women is mostly due to ageing, but mammography may be advisable to rule out the possibility of cancer.

Cracked nipples, common in the last months of pregnancy and during breastfeeding, may lead to infective mastitis. Washing, drying, and moisturizing the nipple daily can help to prevent cracking. Papilloma of the nipple is a noncancerous swelling attached to the skin by a stalk. Paget’s disease of the nipple appears initially as persistent eczema of the nipple and is due to a slow-growing cancer arising in a milk duct. Surgical treatment is required.Discharge from the nipple occurs for various reasons.

A clear, straw-coloured discharge may develop in early pregnancy; a milky discharge may occur after breast-feeding is over.

Galactorrhoea (milk discharge in someone who is not pregnant or breast-feeding) may be caused by a hormone imbalance, or, rarely, a galactocele (a cyst under the areola).

A discharge containing pus indicates a breast abscess.

A bloodstained discharge may be due to a noncancerous breast disorder or cancer.... nipple




Recent Searches