Perineum Health Dictionary

Perineum: From 3 Different Sources


The area bounded internally by the pelvic floor (the muscles that support the pelvis) and the surrounding bony structures. Externally, the perineum is the area that lies behind the genitals and in front of the anus.
Health Source: BMA Medical Dictionary
Author: The British Medical Association
Popularly called the crotch, or crutch, this is the region situated between the opening of the bowel behind and of the genital organs in front. In women it becomes stretched in childbirth, and the vaginal opening may tear or need to be cut (see EPISIOTOMY) to facilitate delivery of the baby.
Health Source: Medical Dictionary
Author: Health Dictionary
n. the region of the body between the anus and the urethral opening, including both skin and underlying muscle. In females it is perforated by the vaginal opening. —perineal adj.
Health Source: Oxford | Concise Colour Medical Dictionary
Author: Jonathan Law, Elizabeth Martin

Episiotomy

A cut made in the PERINEUM to enlarge the vaginal opening and facilitate childbirth during a di?cult birth when the baby’s head (or in a breech delivery, the buttocks) is making slow progress down the birth canal, or when forceps have to be applied. (See PREGNANCY AND LABOUR.)... episiotomy

Hypospadias

A developmental abnormality in the male, in which the URETHRA opens on the undersurface of the penis or in the PERINEUM. The condition is treatable with surgery, but several operations over a period of years may be required to ensure normal urinary and sexual functions.... hypospadias

Burns And Scalds

Burns are injuries caused by dry heat, scalds by moist heat, but the two are similar in symptoms and treatment. Severe burns are also caused by contact with electric wires, and by the action of acids and other chemicals. The burn caused by chemicals di?ers from a burn by ?re only in the fact that the outcome is more favourable, because the chemical destroys the bacteria on the affected part(s) so that less suppuration follows.

Severe and extensive burns are most frequently produced by the clothes – for example, of a child – catching ?re. This applies especially to cotton garments, which blaze up quickly. It should be remembered that such a ?ame can immediately be extinguished by making the individual lie on the ?oor so that the ?ames are uppermost, and wrapping him or her in a rug, mat or blanket. As prevention is always better than cure, particular care should always be exercised with electric ?res and kettles or pots of boiling water in houses where there are young children or old people. Children’s clothes, and especially night-clothes, should be made of non-in?ammable material: pyjamas are also much safer than nightdresses.

Severe scalds are usually produced by escape of steam in boiler explosions. Cigarettes are a common cause of ?res and therefore of burns; people who have fallen asleep in bed or in a chair while smoking may set ?re to the bed or chair. Discarded, unextinguished cigarettes are another cause.

Degrees of burns Burns are referred to as either super?cial (or partial-thickness) burns, when there is su?cient skin tissue left to ensure regrowth of skin over the burned site; and deep (or full-thickness) burns, when the skin is totally destroyed and grafting will be necessary.

Symptoms Whilst many domestic burns are minor and insigni?cant, more severe burns and scalds can prove to be very dangerous to life. The main danger is due to SHOCK, which arises as a result of loss of ?uid from the circulating blood at the site of a serious burn. This loss of ?uid leads to a fall in the volume of the circulating blood. As the maintenance of an adequate blood volume is essential to life, the body attempts to compensate for this loss by withdrawing ?uid from the uninjured areas of the body into the circulation. If carried too far, however, this in turn begins to affect the viability of the body cells. As a sequel, essential body cells, such as those of the liver and kidneys, begin to suffer, and the liver and kidneys cease to function properly. This will show itself by the development of JAUNDICE and the appearance of albumin in the urine (see PROTEINURIA). In addition, the circulation begins to fail with a resultant lack of oxygen (see ANOXIA) in the tissues, and the victim becomes cyanosed (see CYANOSIS), restless and collapsed: in some cases, death ensues. In addition, there is a strong risk of infection occurring. This is the case with severe burns in particular, which leave a large raw surface exposed and very vulnerable to any micro-organisms. The combination of shock and infection can all too often be life-threatening unless expert treatment is immediately available.

The immediate outcome of a burn is largely determined by its extent. This is of more signi?cance than the depth of the burn. To assess the extent of a burn in relation to the surface of the body, what is known as the Rule of Nine has been evolved. The head and each arm cover 9 per cent of the body surface, whilst the front of the body, the back of the body, and each leg each cover 18 per cent, with the perineum (or crutch) accounting for the remaining 1 per cent. The greater the extent of the burn, the more seriously ill will the victim become from loss of ?uid from his or her circulation, and therefore the more prompt should be his or her removal to hospital for expert treatment. The depth of the burn, unless this is very great, is mainly of import when the question arises as to how much surgical treatment, including skin grafting, will be required.

Treatment This depends upon the severity of the burn. In the case of quite minor burns or scalds, all that may be necessary if they are seen immediately is to hold the part under cold running water until the pain is relieved. Cooling is one of the most e?ective ways of relieving the pain of a burn. If the burn involves the distal part of a limb – for example, the hand and forearm – one of the most e?ective ways of relieving pain is to immerse the burned part in lukewarm water and add cold water until the pain disappears. As the water warms and pain returns, more cold water is added. After some three to four hours, pain will not reappear on warming, and the burn may be dressed in the usual way. Thereafter a simple dressing (e.g. a piece of sterile gauze covered by cotton-wool, and on top of this a bandage or adhesive dressing) should be applied. The part should be kept at rest and the dressing kept quite dry until healing takes place. Blisters should be pierced with a sterile needle, but the skin should not be cut away. No ointment or oil should be applied, and an antiseptic is not usually necessary.

In slightly more severe burns or scalds, it is probably advisable to use some antiseptic dressing. These are the cases which should be taken to a doctor – whether a general practitioner, a factory doctor, or to a hospital Accident & Emergency department. There is still no general consensus of expert opinion as to the best ‘antiseptic’ to use. Among those recommended are CHLORHEXIDINE, and antibiotics such as BACITRACIN, NEOMYCIN and polymixin. An alternative is to use a Tulle Gras dressing which has been impregnated with a suitable antibiotic.

In the case of severe burns and scalds, the only sound rule is immediate removal to hospital. Unless there is any need for immediate resuscitation, such as arti?cial respiration, or attention to other injuries there may be, such as fractures or haemorrhage, nothing should be done on the spot to the patient except to make sure that s/he is as comfortable as possible and to keep them warm, and to cover the burn with a sterile (or clean) cloth such as a sheet, pillowcases, or towels wrung out in cold water. If pain is severe, morphine should be given – usually intravenously. Once the victim is in hospital, the primary decision is as to the extent of the burn, and whether or not a transfusion is necessary. If the burn is more than 9 per cent of the body surface in extent, a transfusion is called for. The precise treatment of the burn varies, but the essential is to prevent infection if this has not already occurred, or, if it has, to bring it under control as quickly as possible. The treatment of severe burns has made great advances, with quick transport to specialised burns units, modern resuscitative measures, the use of skin grafting and other arti?cial covering techniques and active rehabilitation programmes, o?ering victims a good chance of returning to normal life.

CHEMICAL BURNS Phenol or lysol can be washed o? promptly before they do much damage. Acid or alkali burns should be neutralised by washing them repeatedly with sodium bicarbonate or 1 per cent acetic acid, respectively. Alternatively, the following bu?er solution may be used for either acid or alkali burns: monobasic potassium phosphate (70 grams), dibasic sodium phosphate (70 grams) in 850 millilitres of water. (See also PHOSPHORUS BURNS.)... burns and scalds

Condom

A thin rubber or plastic sheath placed over the erect PENIS before sexual intercourse. It is the most e?ective type of barrier contraception and is also valuable in preventing the transfer between sexual partners of pathogenic organisms such as gonococci, which cause GONORRHOEA, and human immuno-de?ciency virus, which may lead to AIDS (see AIDS/HIV). Sheaths are most e?ective when properly used and with spermicides.

The female condom might be suitable for contraception when a woman misses a day or two of her contraceptive pill; if there is DYSPAREUNIA; when the perineum needs protection, for example, after childbirth; or in cases of latex allergy to traditional condoms. Used properly with spermicide, it provides an e?ective barrier both to infections and to spermatozoa. Failure may result if the penis goes alongside the condom, if it gets pushed up into the vagina, or if it falls out. (See CONTRACEPTION.)... condom

Crotch

See PERINEUM.... crotch

Crutch

(1) An aid to support the weight of the body for a person unable to bear weight on one of his or her legs. Made of wood or metal, usually long enough to reach from the person’s armpit to the ground, it has a concave surface that ?ts under the arm and a cross-bar for the hand. An elbow crutch provides weight-bearing support using the forearm and elbow and is usually recommended when the leg can take some weight.

(2) See PERINEUM.... crutch

Cystitis

In?ammation of the URINARY BLADDER. The presenting symptom is usually dysuria – that is, a feeling of discomfort when urine is passed and frequently a stinging or burning pain in the URETHRA. There is also a feeling of wanting to pass water much more often than usual, even though there is very little urine present when the act is performed. The condition may be associated with a dragging ache in the lower abdomen, and the urine usually looks dark or stronger than normal. It is frequently associated with haematuria, which means blood in the urine and is the result of the in?ammation.

Cystitis is a common problem; more than half the women in Britain suffer from it at some time in their lives. The cause of the disease is a bacterial infection of the bladder, the germs having entered the urethra and ascended into the bladder. The most common organism responsible is called Escherichia coli. This organism normally lives in the bowel where it causes no harm. It is therefore likely to be present on the skin around the anus so that there is always a potential for infection. The disease is much more common in women because the urethra, vagina and anus are very close together and the urethra is much shorter in the female than it is in the male. It also explains why women commonly suffer cystitis after sexual intercourse and honeymoon cystitis is a very common presentation of bladder in?ammation. In most cases the in?ammation is more of a nuisance than a danger but the infection can spread up to the kidneys and cause PYELITIS which is a much more serious disorder.

In cases of cystitis the urine should be cultured to grow the responsible organism. The relevant antibiotic can then be prescribed. Fluids should be taken freely not only for an acute attack of cystitis but also to prevent further attacks, because if the urine is dilute the organism is less likely to grow. Bicarbonate of soda is also helpful as this reduces the acidity of the urine and helps to relieve the burning pain, and inhibits the growth of the bacteria. Careful hygiene, in order to keep the PERINEUM clean, is also important. (See URINARY BLADDER, DISEASES OF.)... cystitis

Extravasation

An escape of ?uid from the vessels or passages which ought to contain it. Extravasation of blood due to tearing of vessel walls is found in STROKE, and in the commoner condition known as a bruise. Extravasation of urine takes place when the bladder or the URETHRA is ruptured by a blow on the abdomen or on the crutch (PERINEUM), or torn in a fracture of the pelvis. Intravenous infusions frequently extravasate.... extravasation

Hydradenitis Suppurativa

A chronic in?ammatory disease of the apocrine sweat glands (see PERSPIRATION). It is more common in women – in whom it usually occurs in the armpit – than in men, in whom it is most common in the perineum of the drivers of lorries and taxis. It occurs in the form of painful, tender lumps underneath the skin, which burst often in a week or so. Treatment consists of removal by operation.... hydradenitis suppurativa

Pregnancy And Labour

Pregnancy The time when a woman carries a developing baby in her UTERUS. For the ?rst 12 weeks (the ?rst trimester) the baby is known as an EMBRYO, after which it is referred to as the FETUS.

Pregnancy lasts about 280 days and is calculated from the ?rst day of the last menstrual period – see MENSTRUATION. Pregnancy-testing kits rely on the presence of the hormone beta HUMAN CHORIONIC GONADOTROPHIN (b HCG) which is excreted in the woman’s urine as early as 30 days from the last menstrual period. The estimated date of delivery can be accurately estimated from the size of the developing fetus measured by ULTRASOUND (see also below) between seven and 24 weeks. ‘Term’ refers to the time that the baby is due; this can range from 38 weeks to 41 completed weeks.

Physical changes occur in early pregnancy – periods stop and the abdomen enlarges. The breasts swell, with the veins becoming prominent and the nipples darkening. About two in three women will have nausea with a few experiencing such severe vomiting as to require hospital admission for rehydration.

Antenatal care The aim of antenatal care is to ensure a safe outcome for both mother and child; it is provided by midwives (see MIDWIFE) and doctors. Formal antenatal care began in Edinburgh in the 1930s with the recognition that all aspects of pregnancy – normal and abnormal – warranted surveillance. Cooperation between general practitioners, midwives and obstetricians is now established, with pregnancies that are likely to progress normally being cared for in the community and only those needing special intervention being cared for in a hospital setting.

The initial visit (or booking) in the ?rst half of pregnancy will record the history of past events and the results of tests, with the aim of categorising the patients into normal or not. Screening tests including blood checks and ultrasound scans are a routine part of antenatal care. The ?rst ultrasound scan is done at about 11 weeks to date the pregnancy, with a further one done at 20 weeks – the anomaly scan – to assess the baby’s structure. Some obstetric units will check the growth of the baby with one further scan later in the pregnancy or, in the case of twin pregnancies (see below), many scans throughout. The routine blood tests include checks for ANAEMIA, DIABETES MELLITUS, sickle-cell disease and THALASSAEMIA, as well as for the blood group. Evidence of past infections is also looked for; tests for RUBELLA (German measles) and SYPHILIS are routine, whereas tests for human immunode?ciency virus (see AIDS/ HIV below) and HEPATITIS are being o?ered as optional, although there is compelling evidence that knowledge of the mother’s infection status is bene?cial to the baby.

Traditional antenatal care consists of regular appointments, initially every four weeks until 34 weeks, then fortnightly or weekly. At each visit the mother’s weight, urine and blood pressure are checked, and assessment of fetal growth and position is done by palpating the uterus. Around two-thirds of pregnancies and labours are normal: in the remainder, doctors and midwives need to increase the frequency of surveillance so as to prevent or deal with maternal and fetal problems.

Common complications of pregnancy

Some of the more common complications of pregnancy are listed below.

As well as early detection of medical complications, antenatal visits aim to be supportive and include emotional and educational care. Women with uncomplicated pregnancies are increasingly being managed by midwives and general practitioners in the community and only coming to the hospital doctors should they develop a problem. A small number will opt for a home delivery, but facilities for providing such a service are not always available in the UK.

Women requiring more intensive surveillance have their management targeted to the speci?c problems encountered. Cardiologists will see mothers-to-be with heart conditions, and those at risk of diabetes are cared for in designated clinics with specialist sta?. Those women needing more frequent surveillance than standard antenatal care can be looked after in maternity day centres. These typically include women with mildly raised blood pressure or those with small babies. Fetal medicine units have specialists who are highly skilled in ultrasound scanning and specialise in the diagnosis and management of abnormal babies still in the uterus. ECTOPIC PREGNANCY Chronic abdominal discomfort early in pregnancy may be caused by unruptured ectopic pregnancy, when, rarely, the fertilised OVUM starts developing in the Fallopian tube (see FALLOPIAN TUBES) instead of the uterus. The patient needs hospital treatment and LAPAROSCOPY. A ruptured ectopic pregnancy causes acute abdominal symptoms and collapse, and the woman will require urgent abdominal surgery. URINARY TRACT INFECTIONS These affect around 2 per cent of pregnant women and are detected by a laboratory test of a mid-stream specimen of urine. In pregnancy, symptoms of these infections do not necessarily resemble those experienced by non-pregnant women. As they can cause uterine irritability and possible premature labour (see below), it is important to ?nd and treat them appropriately. ANAEMIA is more prevalent in patients who are vegetarian or on a poor diet. Iron supplements are usually given to women who have low concentrations of HAEMOGLOBIN in their blood (less than 10.5 g/dl) or who are at risk of becoming low in iron, from bleeding, twin pregnancies and those with placenta previa (see below). ANTEPARTUM HAEMORRHAGE Early in pregnancy, vaginal bleedings may be due to a spontaneous or an incomplete therapeutic ABORTION. Bleeding from the genital tract between 24 completed weeks of pregnancy and the start of labour is called antepartum haemorrhage. The most common site is where the PLACENTA is attached to the wall of the uterus. If the placenta separates before delivery, bleeding occurs in the exposed ‘bed’. When the placenta is positioned in the upper part of the uterus it is called an abruption. PLACENTA PRAEVIA is sited in the lower part and blocks or partly blocks the cervix (neck of the womb); it can be identi?ed at about the 34th week. Ten per cent of episodes of antepartum bleeding are caused by placenta previa, and it may be associated with bleeding at delivery. This potentially serious complication is diagnosed by ultrasound scanning and may require a caesarean section (see below) at delivery. INCREASED BLOOD PRESSURE, associated with protein in the urine and swelling of the limbs, is part of a condition known as PRE-ECLAMPSIA. This occurs in the second half of pregnancy in about 1 in 10 women expecting their ?rst baby, and is mostly very mild and of no consequence to the pregnancy. However, some women can develop extremely high blood pressures which can adversely affect the fetus and cause epileptic-type seizures and bleeding disorders in the mother. This serious condition is called ECLAMPSIA. For this reason a pregnant woman with raised blood pressure or PROTEIN in her urine is carefully evaluated with blood tests, often in the maternity day assessment unit. The condition can be stopped by delivery of the baby, and this will be done if the mother’s or the fetus’s life is in danger. If the condition is milder, and the baby not mature enough for a safe delivery, then drugs can be used to control the blood pressure. MISCARRIAGE Also called spontaneous abortion, miscarriage is the loss of the fetus. There are several types:

threatened miscarriage is one in which some vaginal bleeding occurs, the uterus is enlarged, but the cervix remains closed and pregnancy usually proceeds.

inevitable miscarriage usually occurs before the 16th week and is typi?ed by extensive blood loss through an opened cervix and cramp-like abdominal pain; some products of conception are lost but the developing placental area (decidua) is retained and an operation may be necessary to clear the womb.

missed miscarriages, in which the embryo dies and is absorbed, but the decidua (placental area of uterine wall) remains and may cause abdominal discomfort and discharge of old blood.

THERAPEUTIC ABORTION is performed on more than 170,000 women annually in England and Wales. Sometimes the woman may not have arranged the procedure through the usual health-care channels, so that a doctor may see a patient with vaginal bleeding, abdominal discomfort or pain, and open cervix – symptoms which suggest that the decidua and a blood clot have been retained; these retained products will need to be removed by curettage.

Septic abortions are now much less common in Britain than before the Abortion Act (1967) permitted abortion in speci?ed circumstances. The cause is the passage of infective organisms from the vagina into the uterus, with Escherichia coli and Streptococcus faecalis the most common pathogenic agents. The woman has abdominal pain, heavy bleeding, usually fever and sometimes she is in shock. The cause is usually an incomplete abortion or one induced in unsterile circumstances. Antibiotics and curettage are the treatment. INTRAUTERINE GROWTH RETARDATION describes a slowing of the baby’s growth. This can be diagnosed by ultrasound scanning, although there is a considerable margin of error in estimates of fetal weight. Trends in growth are favoured over one-o? scan results alone. GESTATIONAL DIABETES is a condition that is more common in women who are overweight or have a family member with diabetes. If high concentrations of blood sugar are found, e?orts are made to correct it as the babies can become very fat (macrosomia), making delivery more di?cult. A low-sugar diet is usually enough to control the blood concentration of sugars; however some women need small doses of INSULIN to achieve control. FETAL ABNORMALITIES can be detected before birth using ultrasound. Some of these defects are obvious, such as the absence of kidneys, a condition incompatible with life outside the womb. These women can be o?ered a termination of their pregnancy. However, more commonly, the pattern of problems can only hint at an abnormality and closer examination is needed, particularly in the diagnosis of chromosomal deformities such as DOWN’S (DOWN) SYNDROME (trisomy 21 or presence of three 21 chromosomes instead of two).

Chromosomal abnormalities can be de?nitively diagnosed only by cell sampling such as amniocentesis (obtaining amniotic ?uid – see AMNION – from around the baby) done at 15 weeks onwards, and chorionic villus sampling (sampling a small part of the placenta) – another technique which can be done from 12 weeks onwards. Both have a small risk of miscarriage associated with them; consequently, they are con?ned to women at higher risk of having an abnormal fetus.

Biochemical markers present in the pregnant woman’s blood at di?erent stages of pregnancy may have undergone changes in those carrying an abnormal fetus. The ?rst such marker to be routinely used was a high concentration of alpha-fetol protein in babies with SPINA BIFIDA (defects in the covering of the spinal cord). Fuller research has identi?ed a range of diagnostic markers which are useful, and, in conjunction with other factors such as age, ethnic group and ultrasound ?ndings, can provide a predictive guide to the obstetrician – in consultation with the woman – as to whether or not to proceed to an invasive test. These tests include pregnancy-associated plasma protein assessed from a blood sample taken at 12 weeks and four blood tests at 15–22 weeks – alphafetol protein, beta human chorionic gonadotrophin, unconjugated oestriol and inhibin A. Ultrasound itself can reveal physical ?ndings in the fetus, which can be more common in certain abnormalities. Swelling in the neck region of an embryo in early pregnancy (increased nuchal thickness) has good predictive value on its own, although its accuracy is improved in combination with the biochemical markers. The e?ectiveness of prenatal diagnosis is rapidly evolving, the aim being to make the diagnosis as early in the pregnancy as possible to help the parents make more informed choices. MULTIPLE PREGNANCIES In the UK, one in 95 deliveries is of twins, while the prevalence of triplets is one in 10,000 and quadruplets around one in 500,000. Racial variations occur, with African women having a prevalence rate of one in 30 deliveries for twins and Japanese women a much lower rate than the UK ?gure. Multiple pregnancies occur more often in older women, and in the UK the prevalence of fertility treatments, many of these being given to older women, has raised the incidence. There is now an o?cial limit of three eggs being transferred to a woman undergoing ASSISTED CONCEPTION (gamete intrafallopian transfer, or GIFT).

Multiple pregnancies are now usually diagnosed as a result of routine ultrasound scans between 16 and 20 weeks of pregnancy. The increased size of the uterus results in the mother having more or worse pregnancy-related conditions such as nausea, abdominal discomfort, backache and varicose veins. Some congenital abnormalities in the fetus occur more frequently in twins: NEURAL TUBE defects, abnormalities of the heart and the incidence of TURNER’S SYNDROME and KLINEFELTER’S SYNDROME are examples. Such abnormalities may be detected by ultrasound scans or amniocentesis. High maternal blood pressure and anaemia are commoner in women with multiple pregnancies (see above).

The growth rates of multiple fetuses vary, but the di?erence between them and single fetuses are not that great until the later stages of pregnancy. Preterm labour is commoner in multiple pregnancies: the median length of pregnancy is 40 weeks for singletons, 37 for twins and 33 for triplets. Low birth-weights are usually the result of early delivery rather than abnormalities in growth rates. Women with multiple pregnancies require more frequent and vigilant antenatal assessments, with their carers being alert to the signs of preterm labour occurring. CEPHALOPELVIC DISPROPORTION Disparity between the size of the fetus and the mother’s pelvis is not common in the UK but is a signi?cant problem in the developing world. Disparity is classi?ed as absolute, when there is no possibility of delivery, and relative, when the baby is large but delivery (usually after a dif?cult labour) is possible. Causes of absolute disparity include: a large baby – heavier than 5 kg at birth; fetal HYDROCEPHALUS; and an abnormal maternal pelvis. The latter may be congenital, the result of trauma or a contraction in pelvic size because of OSTEOMALACIA early in life. Disproportion should be suspected if in late pregnancy the fetal head has not ‘engaged’ in the pelvis. Sometimes a closely supervised ‘trial of labour’ may result in a successful, if prolonged, delivery. Otherwise a caesarean section (see below) is necessary. UNUSUAL POSITIONS AND PRESENTATIONS OF THE BABY In most pregnant women the baby ?ts into the maternal pelvis head-?rst in what is called the occipito-anterior position, with the baby’s face pointing towards the back of the pelvis. Sometimes, however, the head may face the other way, or enter the pelvis transversely – or, rarely, the baby’s neck is ?exed backwards with the brow or face presenting to the neck of the womb. Some malpositions will correct naturally; others can be manipulated abdominally during pregnancy to a better position. If, however, the mother starts labour with the baby’s head badly positioned or with the buttocks instead of the head presenting (breech position), the labour will usually be longer and more di?cult and may require intervention using special obstetric forceps to assist in extracting the baby. If progress is poor and the fetus distressed, caesarean section may be necessary. HIV INFECTION Pregnant women who are HIV positive (see HIV; AIDS/HIV) should be taking antiviral drugs in the ?nal four to ?ve months of pregnancy, so as to reduce the risk of infecting the baby in utero and during birth by around 50 per cent. Additional antiviral treatment is given before delivery; the infection risk to the baby can be further reduced – by about 40 per cent – if delivery is by caesarean section. The mother may prefer to have the baby normally, in which case great care should be taken not to damage the baby’s skin during delivery. The infection risk to the baby is even further reduced if it is not breast fed. If all preventive precautions are taken, the overall risk of the infant becoming infected is cut to under 5 per cent.

Premature birth This is a birth that takes place before the end of the normal period of gestation, usually before 37 weeks. In practice, however, it is de?ned as a birth that takes place when the baby weighs less than 2·5 kilograms (5••• pounds). Between 5 and 10 per cent of babies are born prematurely, and in around 40 per cent of premature births the cause is unknown. Pre-eclampsia is the most common known cause; others include hypertension, chronic kidney disease, heart disease and diabetes mellitus. Multiple pregnancy is another cause. In the vast majority of cases the aim of management is to prolong the pregnancy and so improve the outlook for the unborn child. This consists essentially of rest in bed and sedation, but there are now several drugs, such as RITODRINE, that may be used to suppress the activity of the uterus and so help to delay premature labour. Prematurity was once a prime cause of infant mortality but modern medical care has greatly improved survival rates in developing countries.

Labour Also known by the traditional terms parturition, childbirth or delivery, this is the process by which the baby and subsequently the placenta are expelled from the mother’s body. The onset of labour is often preceded by a ‘show’ – the loss of the mucus and blood plug from the cervix, or neck of the womb; this passes down the vagina to the exterior. The time before the beginning of labour is called the ‘latent phase’ and characteristically lasts 24 hours or more in a ?rst pregnancy. Labour itself is de?ned by regular, painful contractions which cause dilation of the neck of the womb and descent of the fetal head. ‘Breaking of the waters’ is the loss of amniotic ?uid vaginally and can occur any time in the delivery process.

Labour itself is divided into three stages: the ?rst is from the onset of labour to full (10 cm) dilation of the neck of the womb. This stage varies in length, ideally taking no more than one hour per centimetre of dilation. Progress is monitored by regular vaginal examinations, usually every four hours. Fetal well-being is observed by intermittent or continuous monitoring of the fetal heart rate in relation to the timing and frequency of the contractions. The print-out is called a cardiotocograph. Abnormalities of the fetal heart rate may suggest fetal distress and may warrant intervention. In women having their ?rst baby (primigravidae), the common cause of a slow labour is uncoordinated contractions which can be overcome by giving either of the drugs PROSTAGLANDIN or OXYTOCIN, which provoke contractions of the uterine muscle, by an intravenous drip. Labours which progress slowly or not at all may be due to abnormal positioning of the fetus or too large a fetus, when prostaglandin or oxytocin is used much more cautiously.

The second stage of labour is from full cervical dilation to the delivery of the baby. At this stage the mother often experiences an irresistible urge to push the baby out, and a combination of strong coordinated uterine contractions and maternal e?ort gradually moves the baby down the birth canal. This stage usually lasts under an hour but can take longer. Delay, exhaustion of the mother or distress of the fetus may necessitate intervention by the midwife or doctor. This may mean enlarging the vaginal opening with an EPISIOTOMY (cutting of the perineal outlet – see below) or assisting the delivery with specially designed obstetric forceps or a vacuum extractor (ventouse). If the cervix is not completely dilated or open and the head not descended, then an emergency caesarean section may need to be done to deliver the baby. This procedure involves delivering the baby and placenta through an incision in the mother’s abdomen. It is sometimes necessary to deliver by planned or elective caesarean section: for example, if the placenta is low in the uterus – called placenta praevia – making a vaginal delivery dangerous.

The third stage occurs when the placenta (or afterbirth) is delivered, which is usually about 10–20 minutes after the baby. An injection of ergometrine and oxytocin is often given to women to prevent bleeding.

Pain relief in labour varies according to the mother’s needs. For uncomplicated labours, massage, reassurance by a birth attendant, and a warm bath and mobilisation may be enough for some women. However, some labours are painful, particularly if the woman is tired or anxious or is having her ?rst baby. In these cases other forms of analgesia are available, ranging from inhalation of NITROUS OXIDE GAS, injection of PETHIDINE HYDROCHLORIDE or similar narcotic, and regional local anaesthetic (see ANAESTHESIA).

Once a woman has delivered, care continues to ensure her and the baby’s safety. The midwives are involved in checking that the uterus returns to its normal size and that there is no infection or heavy bleeding, as well as caring for stitches if needed. The normal blood loss after birth is called lochia and generally is light, lasting up to six weeks. Midwives o?er support with breast feeding and care of the infant and will visit the parents at home routinely for up to two weeks.

Some complications of labour All operative deliveries in the UK are now done in hospitals, and are performed if a spontaneous birth is expected to pose a bigger risk to the mother or her child than a specialist-assisted one. Operative deliveries include caesarean section, forceps-assisted deliveries and those in which vacuum extraction (ventouse) is used. CAESAREAN SECTION Absolute indications for this procedure, which is used to deliver over 15 per cent of babies in Britain, are cephalopelvic disproportion and extensive placenta praevia, both discussed above. Otherwise the decision to undertake caesarean section depends on the clinical judgement of the specialist and the views of the mother. The rise in the proportion of this type of intervention (from 5 per cent in the 1930s to its present level of over 23 per cent

P

of the 600,000 or so annual deliveries in England) has been put down to defensive medicine

– namely, the doctor’s fear of litigation (initiated often because the parents believe that the baby’s health has suffered because the mother had an avoidably di?cult ‘natural’ labour). In Britain, over 60 per cent of women who have had a caesarean section try a vaginal delivery in a succeeding pregnancy, with about two-thirds of these being successful. Indications for the operation include:

absolute and relative cephalopelvic disproportion.

placenta previa.

fetal distress.

prolapsed umbilical cord – this endangers the viability of the fetus because the vital supply of oxygen and nutrients is interrupted.

malpresentation of the fetus such as breech or transverse lie in the womb.

unsatisfactory previous pregnancies or deliveries.

a request from the mother.

Caesarean sections are usually performed using regional block anaesthesia induced by a spinal or epidural injection. This results in loss of feeling in the lower part of the body; the mother is conscious and the baby not exposed to potential risks from volatile anaesthetic gases inhaled by the mother during general anaesthesia. Post-operative complications are higher with general anaesthesia, but maternal anxiety and the likelihood that the operation might be complicated and di?cult are indications for using it. A general anaesthetic may also be required for an acute obstetric emergency. At operation the mother’s lower abdomen is opened and then her uterus opened slowly with a transverse incision and the baby carefully extracted. A transverse incision is used in preference to the traditional vertical one as it enables the woman to have a vaginal delivery in any future pregnancy with a much smaller risk of uterine rupture. Women are usually allowed to get up within 24 hours and are discharged after four or ?ve days. FORCEPS AND VENTOUSE DELIVERIES Obstetric forceps are made in several forms, but all are basically a pair of curved blades shaped so that they can obtain a purchase on the baby’s head, thus enabling the operator to apply traction and (usually) speed up delivery. (Sometimes they are used to slow down progress of the head.) A ventouse or vacuum extractor comprises an egg-cup-shaped metal or plastic head, ranging from 40 to 60 mm in diameter with a hollow tube attached through which air is extracted by a foot-operated vacuum pump. The instrument is placed on the descending head, creating a negative pressure on the skin of the scalp and enabling the operator to pull the head down. In mainland Europe, vacuum extraction is generally preferred to forceps for assisting natural deliveries, being used in around 5 per cent of all deliveries. Forceps have a greater risk of causing damage to the baby’s scalp and brain than vacuum extraction, although properly used, both types should not cause any serious damage to the baby.

Episiotomy Normal and assisted deliveries put the tissues of the genital tract under strain. The PERINEUM is less elastic than the vagina and, if it seems to be splitting as the baby’s head

moves down the birth canal, it may be necessary to cut the perineal tissue – a procedure called an episiotomy – to limit damage. This is a simple operation done under local anaesthetic. It should be done only if there is a speci?c indication; these include:

to hasten the second stage of labour if the fetus is distressed.

to facilitate the use of forceps or vacuum extractor.

to enlarge a perineum that is restricted because of unyielding tissue, perhaps because of a scar from a previous labour. Midwives as well as obstetricians are trained

to undertake and repair (with sutures) episiotomies.

(For organisations which o?er advice and information on various aspects of childbirth, including eclampsia, breast feeding and multiple births, see APPENDIX 2: ADDRESSES: SOURCES OF INFORMATION, ADVICE, SUPPORT AND SELF-HELP.)... pregnancy and labour

Forceps Delivery

The use of forceps (see forceps, obstetric) to ease out the baby’s head during a difficult birth (see childbirth). Forceps delivery is used if

the mother is unable to push out her baby unaided, or if the baby is showing signs of fetal distress. Forceps are also used to control the head once the body has been delivered in breech delivery to prevent too rapid a birth.An episiotomy (making of a cut in the perineum) is usually needed for a forceps delivery. Recovery and care for mother and child is usually the same as after a vaginal delivery.... forceps delivery

Burns–marshall Manoeuvre

a manoeuvre used during an assisted *breech presentation. The baby’s legs and trunk should be allowed to hang until the nape of the neck is visible at the mother’s perineum so that its weight exerts gentle downwards and backwards traction to promote flexion of the head. The fetal trunk is then swept in a wide arc over the maternal abdomen by grasping both the feet and maintaining gentle traction; the aftercoming head is slowly born in this process.

burr n. see bur.... burns–marshall manoeuvre

Haemorrhoids

Haemorrhoids, or piles, are varicose (swollen) veins in the lining of the ANUS. They are very common, affecting nearly half of the UK population at some time in their lives, with men having them more often and for a longer time.

Varieties Haemorrhoids are classi?ed into ?rst-, second- and third-degree, depending on how far they prolapse through the anal canal. First-degree ones do not protrude; second-degree piles protrude during defaecation; third-degree ones are trapped outside the anal margin, although they can be pushed back. Most haemorrhoids can be described as internal, since they are covered with glandular mucosa, but some large, long-term ones develop a covering of skin. Piles are usually found at the three, seven and eleven o’clock sites when viewed with the patient on his or her back.

Causes The veins in the anus tend to become distended because they have no valves; because they form the lowest part of the PORTAL SYSTEM and are apt to become over?lled when there is the least interference with the circulation through the portal vein; and partly because the muscular arrangements for keeping the rectum closed interfere with the circulation through the haemorrhoidal veins. An absence of ?bre from western diets is probably the most important cause. The result is that people often strain to defaecate hard stools, thus raising intra-abdominal pressure which slows the rate of venous return and engorges the network of veins in the anal mucosa. Pregnancy is an important contributory factor in women developing haemorrhoids. In some people, haemorrhoids are a symptom of disease higher up in the portal system, causing interference with the circulation. They are common in heart disease, liver complaints such as cirrhosis or congestion, and any disease affecting the bowels.

Symptoms Piles cause itching, pain and often bleeding, which may occur whenever the patient defaecates or only sometimes. The piles may prolapse permanently or intermittently. The patient may complain of aching discomfort which, with the pain, may be worsened.

Treatment Prevention is important; a high-?bre diet will help in this, and is also necessary after piles have developed. Patients should not spend a long time straining on the lavatory. Itching can be lessened if the PERINEUM is properly washed, dried and powdered. Prolapsed piles can be replaced with the ?nger. Local anaesthetic and steroid ointments can help to relieve symptoms when they are relatively mild, but do not remedy the underlying disorder. If conservative measures fail, then surgery may be required. Piles may be injected, stretched or excised according to the patient’s particular circumstances.

Where haemorrhoids are secondary to another disorder, such as cancer of the rectum or colon, the underlying condition must be treated – hence the importance of medical advice if piles persist.... haemorrhoids

Prostate Gland, Diseases Of

Disease of the PROSTATE GLAND can affect the ?ow of URINE so that patients present with urological symptoms.

Prostatitis This can be either acute or chronic. Acute prostatitis is caused by a bacterial infection, while chronic prostatitis may follow on from an acute attack, arise insidiously, or be non-bacterial in origin.

Symptoms Typically the patient has pain in the PERINEUM, groins, or supra pubic region, and pain on EJACULATION. He may also have urinary frequency, and urgency.

Treatment Acute and chronic prostatitis are treated with a prolonged course of antibiotics. Patients with chronic prostatitis may also require anti-in?ammatory drugs, and antidepressants.

Prostatic enlargement This is the result of benign prostatic hyperplasia (BPH), causing enlargement of the prostate. The exact cause of this enlargement is unknown, but it affects 50 per cent of men between 40 and 59 years and 95 per cent of men over 70 years.

Symptoms These are urinary hesitancy, poor urinary stream, terminal dribbling, frequency and urgency of urination and the need to pass urine at night (nocturia). The diagnosis is made from the patient’s history; a digital examination of the prostate gland via the rectum to assess enlargement; and analysis of the urinary ?ow rate.

Treatment This can be with tablets, which either shrink the prostate – an anti-androgen drug such as ?nasteride – or relax the urinary sphincter muscle during urination. For more severe symptoms the prostate can be removed surgically, by transurethral resection of prostate (TURP), using either electrocautery or laser energy. A new treatment is the use of microwaves to heat up and shrink the enlarged gland.

Cancer Cancer of the prostate is the fourth most common cause of death from cancer in northern European males: more than 10,000 cases are diagnosed every year in the UK and the incidence is rising by 3 per cent annually.

Little is known about the cause, but the majority of prostate cancers require the male hormones, androgens, to grow.

Symptoms These are similar to those resulting from benign prostatic hypertrophy (see above). Spread of the cancer to bones can cause pain. The use of a blood test measuring the amount of an ANTIGEN, PROSTATE SPECIFIC ANTIGEN (PSA), can be helpful in making the diagnosis – as can an ULTRASOUND scan of the prostate.

Treatment This could be surgical, with removal of the prostate (either via an abdominal incision, total prostatectomy, or transurethrally), or could be by radiotherapy. In more advanced cancers, treatment with anti-androgen drugs, such as cyprotexone acetate or certain oestrogens, is used to inhibit the growth of the cancer.... prostate gland, diseases of

Cryotherapy

n. the destruction of diseased or unwanted tissue based on freezing. For example, prostate cryotherapy involves two alternate freeze-thaw cycles using specialized needles introduced into the prostate through the perineum to destroy cancer cells, either after failed radiotherapy or as a primary treatment. Freezing is performed by the infusion of argon gas through the needles and thawing by the infusion of helium. See also cyclocryotherapy; cryosurgery; hypothermia.... cryotherapy

Fournier’s Gangrene

a rare but potentially life-threatening infection of the scrotum that can rapidly spread to involve the perineum, penis, and anterior abdominal wall. [J. A. Fournier (19th century), French venereologist]... fournier’s gangrene

Imperforate Anus

(proctatresia) partial or complete obstruction of the anus: a congenital malformation in which the anal canal fails to develop correctly and the rectum ends blindly above the muscles of the perineum. Many types exist, including developmental anal stenosis, persistent anal membrane, and covered anus (due to fused genital folds). Most mild cases of imperforate anus can be treated by a simple operation. If the defect is extensive a temporary opening is made in the colon (see colostomy), with later surgical reconstruction of the rectum and anus.... imperforate anus

Paeony

Paeonia lactiflora, Paeonia suffruticosa. German: Paeonie. French: Pivoine. Italian: Peonia. Iranian: Fawania Aod-el-Salib. Indian: Ud salap. Chinese: Bai shae Yae. Parts used: root and root bark.

Constituents. Alkaloids, benzoic acid, asparagin, volatile oil.

Action: antispasmodic, sedative, diuretic, emmenagogue. CNS relaxant, antibacterial, hypotensive, anti- inflammatory, analgesic, liver protector, stimulant to circulatory vessels.

Uses: Old English traditional: epilepsy, chorea. Painful spasm induced by gall or renal stone, whooping cough, children’s convulsions, anal fissure, piles, ulceration of the perineum or coccyx (suppositories, or bathing with strong infusion).

Preparations: Strong infusion: 2oz bruised leaves to 1 pint boiling water; infuse 15 minutes. External use only.

Tincture of the fresh root gathered in spring. 2oz bruised root in 1 pint 45 per cent alcohol. Macerate 8 days, shake daily; filter. Bottle in stoppered amber-coloured bottle. Dose, 10-20 drops thrice daily for the above conditions or when epileptic attack is suspected.

Contra-indications: large doses toxic. For use by medical practitioner only. ... paeony

Childbirth

The process by which an infant leaves the uterus and enters the outside world. Childbirth (labour) normally takes place between 38 and 42 weeks of pregnancy and occurs in 3 stages.

The onset of the 1st stage of labour is marked by regular contractions which become progressively more painful, and occur at shorter intervals. The cervix becomes thinned and softened and then begins to dilate with each contraction. During this time, there may be a “show’’, the mucous plug that blocks the cervical canal during pregnancy is expelled as a bloody discharge. “Breaking of the waters’’, the rupture of the amniotic sac, may occur as a slow trickle of fluid or a sudden gush. The cervix is fully dilated when the opening has widened to about 10 cm in diameter. This may take 12 hours or more for a first baby, but only a few hours for subsequent babies.

In the 2nd stage of labour, the woman feels the urge to push with each strong contraction. As the baby’s head descends into the vagina, it rotates to face the mother’s back. The perineum is stretched thin at this stage, and an episiotomy may be performed to prevent it from tearing. Once the baby’s head is delivered, the rest of the body follows with the next contractions. After delivery, the umbilical cord is clamped and cut.

In the 3rd stage of labour, the delivery of the placenta takes place.

The various forms of pain relief available during normal labour and delivery include opioid analgesic drugs, epidural anaesthesia, and pudendal block.... childbirth

Lithotomy Position

an operating-table position that allows good access to the pelvis and perineum. The patient is placed supine so that the buttocks are at the edge of the table. The feet are placed in individual stirrups and the knees bent to allow the feet to be placed above or at the same level as the hips.... lithotomy position

Median Raphe

a ridge of skin extending from the anus through the perineum. In males it extends further up the scrotum and penis. It represents a fusion line from embryological development and may be the site of cysts and other harmless structures.... median raphe

Perineal Descent

abnormal bulging down of the *perineum as a result of weakness of the pelvic floor muscles. It often accompanies problems with defecation and micturition.... perineal descent

Perineal Tear

(perineal trauma) an injury to the perineum, which may be sustained during childbirth. Perineal tears can be classified by degree. First-degree tears involve the perineal skin and vaginal mucosa only. Second-degree tears involve the perineal muscles but not the anal sphincter. Third-degree tears involve the anal sphincter complex: the external anal sphincter (EAS) and internal anal sphincter (IAS). These are subclassified as 3a (less than 50% of EAS thickness torn), 3b (more than 50% of EAS thickness torn), and 3c (IAS torn). Fourth-degree tears involve the anal sphincter complex (EAS and IAS) and the anal epithelium or rectal mucosa. It is vitally important that these injuries are recognized and repaired by competent personnel. See also obstetric anal sphincter injury.... perineal tear

Perineoplasty

n. an operation designed to enlarge the vaginal opening by incising the hymen and part of the perineum (Fenton’s operation).... perineoplasty

Perineorrhaphy

n. the surgical repair of a damaged perineum. The damage is usually the result of a tear in the perineum sustained during childbirth (see perineal tear).... perineorrhaphy

Urethrostomy

n. the operation of creating an opening of the urethra in the perineum in men. This can be permanent, to bypass a severe *stricture of the urethra in the penis, or it can form the first stage of an operation to cure a stricture of the posterior section of the urethra (*urethroplasty).... urethrostomy

Vasovesiculitis

n. inflammation of the *seminal vesicles and *vas deferens. This usually occurs in association with *prostatitis and causes pain in the perineum, groin, and scrotum and a high temperature. On examination the vasa and seminal vesicles are thickened and tender. Treatment includes administration of antibiotics.... vasovesiculitis



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