Meninges Health Dictionary

Cerebrospinal fever. Inflammation of the pia mater and arachnoid covering of the brain and spinal cord. A notifiable disease. Hospitalisation. Diagnosis is difficult without a lumbar puncture. Caused by a wide range of virus, bacteria, protozoa and fungi. Three most common bacterial causes in England and Wales are N. Meningotidis, H. influenzae and streptococcus-like infection with sore throat; then fever, vomiting, headache and mental confusion; half-open eyes when asleep, delirium, sensitive to light, possibly drifting into coma. Sometimes onset is gradual over 2-3 weeks. Treatment by hospital specialist.

Poor housing and passive smoking suspected. Its association with non-germ meningitis, and inflammatory drugs is well recognised. Also caused by injury or concussion.

Commence by cleansing bowel with Chamomile enema.

Cerebrospinal relaxants indicated: Passion flower (cerebral), Black Cohosh (meningeal), Ladyslipper (spinal meningeal). (A.W. & L.R. Priest)

If patient is cold, give Cayenne pepper in honey to promote brisk circulation.

Aconite and Gelsemium. “For irritation of the meninges of the brain and spinal cord Aconite is indispensible. Combined with Gelsemium for restlessness it is an exceptional remedy. Tincture Aconite (5-15 drops) with Gelsemium (3-10 drops) hourly. Also used in combination with other agents as may be dictated by the course of the disease. (W.W. Martin MD., Kirksville, Mo., USA)

Crawley root. Decoction: 1 teaspoon to half a pint water, simmer 20 minutes. Dose: 1 teaspoon or more 3-4 times daily for children over 6 months. A powerful diaphoretic and sedative. (Dr Baker, Adrian, Michigan, USA)

Lobelia and Echinacea. Equal parts, Liquid Extract 30 drops in water every 3 hours. (Dr Finlay Ellingwood)

Lobelia, alone. Hypodermic injections of Lobelia in five cases of epidemic spinal meningitis, with complete recovery in every case. Dose: 10 drops hourly until symptoms abate, then twice daily. (Dr A.E. Collyer, Ellingwood Therapeutist)

Ecclectic School. Echinacea commended.

Before the Doctor comes. As onset is rapid, often less than 5 hours, an anti-inflammatory is justified. Teas or decoctions from any of the following: Catmint (Catnep), Prickly Ash berries, Pleurisy root, Boneset, Wild Cherry bark, Bugleweed (Virginian), Ladyslipper. When temperature abates and patient feels better: Chamomile tea or cold Gentian decoction with pinch Cayenne.

Hydrotherapy. Hot baths make patient feel worse. Sponge down with cold water.

Protective throat spray: equal parts, Tincture Myrrh and Tincture Goldenseal.

Protective gargle: 10-20 drops Tincture Myrrh and Goldenseal to glass of water.

Garlic. Dr Yan Cai, Department of Neurology, Ren Ji Hospital (affiliated to Shanghai Second Medical University), China, referred to the extensive use of Garlic in Chinese folk medicine and his hospital’s experience with Garlic products – diallyl trisulphide in particular – to treat viral infections including crypotococcal meningitis for which disease results were impressive.

Garlic appears to be a reliable preventative.

Diet. Fast as long as temperature is elevated; with fruit juices, red beet juice, carrot juice or herb teas. Note. GPs and other practitioners may help stop meningitis claiming lives by giving massive doses of Echinacea before they are admitted to hospital.

Note: The infection is often difficult to diagnose. At the end of each year (November and December) when the peak in cases approaches, every feverish patient with headache should be suspected, especially where accompanied by stiff neck.

The above entry is of historic interest only; more effective orthodox treatment being available. ... meningitis

The outermost and strongest of the three membranes or meninges which envelop the brain and spinal cord. In it run vessels which nourish the inner surface of the skull. (See BRAIN.)... dura mater

A very common condition which may vary considerably in severity, type, signi?cance and cause. At one extreme, headache may indicate the presence of a tumour or MENINGITIS, while at the other it may merely indicate a common cold or tiredness. Even so, persistent or recurrent headaches should always be taken seriously. Although the brain itself is insensitive to pain, the surrounding membranes – meninges – are very sensitive, and changes in intracranial arteries, or spasm of the neck or scalp muscles, which may occur for various reasons, may cause considerable pain. In most cases a clinical diagnosis should be possible; further investigations should only be necessary following head injury, if headaches recur, or if neurological signs such as drowsiness, vomiting, confusion, seizures or focal signs develop.

Stress and anxiety are probably the most common causes of headache and, where possible, the reasons – overwork, family problems, unemployment, ?nancial diffculties, etc. – should be tackled. An unpleasant environment such as tra?c pollution or badly ventilated or overcrowded working conditions may provoke headaches in some people, as may excessive smoking or ca?eine intake. MIGRAINE is a characteristic and often disabling type of headache; high blood pressure may cause the condition (see HYPERTENSION); and, occasionally, refractive errors of the eyes (see EYE, DISORDERS OF) are associated with headaches. SINUS infections are often characterised by frontal headaches. Rheumatism in the muscles of the neck and scalp produce headaches; fever is commonly accompanied by a headache; and sunstroke and HEAT STROKE customarily result in headaches. Finally, diseases in the brain such as meningitis, tumours and HAEMORRHAGE may ?rst manifest themselves as persistent or recurrent headaches.

Treatment Obtaining a reliable diagnosis – with the help of further investigations, including CT (see COMPUTED TOMOGRAPHY) or MRI scanning when indicated – should always be the initial aim; treatment in most cases should then be aimed at the underlying condition. Particular concerns include headache that worsens at night or in the early morning; ever-increasing headaches; those associated with abnormal neurological signs on examination; or those associated with ?ts (see FIT).

Whether the cause is physical or stress-induced, used sensibly and for a limited period a low dose of aspirin or paracetamol may be helpful. In many cases of stress-induced headache, however, the most e?ective treatment is relaxation. There are many speci?c treatments for migraine and hypertension. Sinusitis is treated with antibiotics and sometimes by surgery.... headache

Intrathecal means within the membranes or meninges which envelop the SPINAL CORD. The intrathecal space, between the arachnoid and the pia mater, contains the CEREBROSPINAL FLUID (see INTRACRANIAL PRESSURE).... intrathecal

Meningocele is a protusion of the MENINGES of the brain through a defect in the skull. (See SPINA BIFIDA.)... meningocele

Meningoencephalitis is the term applied to infection of the membranes, or MENINGES, of the brain and the underlying brain matter. In practically all cases of MENINGITIS there is some involvement of the underlying brain, and it is when this involvement is considerable that the term, meningoencephalitis, is used. One form that has attracted attention in recent years is that caused by amoebae (see AMOEBA), particularly that known as Naegleria fowleri, in which the infection is acquired through bathing in contaminated water. E?ective chlorination of swimming baths kills this micro-organism.... meningoencephalitis

The space between the arachnoid and the pia mater – two of the membranes covering the BRAIN. (See also MENINGES.)... subarachnoid space

Relating to the space between the strong outer layer of the MENINGES, the membranes which cover the BRAIN, and the arachnoid, which is the middle layer of the meninges. A subdural haemorrhage occurs when bleeding takes place into this space. The trapped blood forms a large blood clot or haematoma within the skull and this causes pressure on the underlying brain. Bleeding may occur slowly as the result of disease or suddenly as the result of injury. Headaches, confusion and drowsiness result, sometimes with paralysis. Medical attention is required urgently if a serious haematoma occurs soon after injury.... subdural

A rare condition that is characterized by chronic inflammation and thickening of the arachnoid mater, which is the middle of the 3 meninges (the membranes that cover the brain and spinal cord).... arachnoiditis

Once known as infantile paralysis, this disease is caused by a viral infection involving the BRAIN and SPINAL CORD. Since the development of e?ective vaccines in the 1950s (see IMMUNISATION), polio has been practically eliminated in most developed countries. People who have not been fully vaccinated, however, may get the disease: it remains a serious risk for unvaccinated travellers to Africa, Asia or southern Europe. Most reported cases are now from sub-Saharan Africa.

Pathology There are three types of virus, infection spreading by the stools-contaminated hands-mouth route. Children are most susceptible.

One attack usually produces permanent immunity, and second attacks are rare. The virus typically affects the anterior horn cells of the spinal cord, especially those in the lumbar region; the grey matter of the brain stem and cortex may also be damaged.

Vaccination is given to infants at two, three and four months: a booster dose is given at around the age of ?ve. The vaccine contains all three types of polio virus. Two types of vaccine are available: inactivated polio virus (IPV) contains dead virus and is administered by injections; oral polio vaccine (OPV) contains live, harmless strains. The latter is used in the United Kingdom.

Symptoms The incubation period is around 7–14 days, the onset being marked by a mild fever and headache which improves after a few days. In around 85 per cent of infected children there is no further progression, but in some – after approximately one week – the symptoms recur, together with neck sti?ness and signs of meningeal irritation (see MENINGES). Weakness of individual muscle groups is common, and may progress – to a variable extent, depending on the distribution of the virus – to widespread PARALYSIS. Involvement of the diaphragm and intercostal muscles may lead to respiratory failure and rapid death unless arti?cial respiration is provided. Involvement of the cranial nerves and brain may lead to nystagmus (see under EYE, DISORDERS OF), hoarseness and di?culty in swallowing, and CONVULSIONS may occur in young children. The CEREBROSPINAL FLUID shows an early increase in lymphocytes, followed by a rise in protein concentration.

Treatment There is no e?ective drug treatment for the infection. Treatment involves early bed rest, followed by PHYSIOTHERAPY and orthopaedic measures as required. At the onset of respiratory diffculties a TRACHEOSTOMY and arti?cial ventilation should be started. (In the 1950s, when polio epidemics were occurring, respiratory diffculties were treated by placing patients in an ‘iron lung’ – a large, airtight, cylindrical container in which the air pressure was raised and lowered to simulate normal breathing.) In cases of severe paralysis with persistent wasting of the limbs, surgery may be necessary to minimise the resulting disability.... poliomyelitis

Tuberculosis results form infection with Mycobacterium tuberculosis. The lungs are the site most often affected, but most organs in the body can be involved in tuberculosis. The other common sites are LYMPH NODES, bones, gastrointestinal tract, kidneys, skin and MENINGES.

The weight loss and wasting associated with tuberculosis before treatment was available led to the disease’s popular name of consumption. Enlargement of the glands in the neck, formerly called scrofula, was known also as the ‘king’s evil’ from the supersition that a touch of the royal hand could cure the condition. Lupus vulgaris (see under LUPUS) is another of the skin manifestations of the disease.

The typical pathological change in tuberculosis involves the formation of clusters of cells called granulomas (see GRANULOMA) with death of the cells in the centre producing CASEATION.

It is estimated that there are 7–8 million new cases of tuberculosis worldwide each year, with 2–3 million deaths. The incidence of tuberculosis in developed countries has shown a steady decline throughout the 20th century, mainly as a result of improved nutrition and social conditions and accelerated by the development of antituberculous chemotherapy in the 1940s. Since the mid-1980s the decline has stopped, and incidence has even started to rise again in inner-city areas. In 2002, 7,239 cases of tuberculosis were noti?ed in the UK compared with 6,442 a decade earlier; more than 390 deaths in 2003 were attributed to the disease. Factors involved in this rise are immigration from higher-prevalence areas, poorer social conditions and homelessness in some urban centres and the association with HIV infection and drug abuse. The incidence of tuberculosis is also rising in many developing countries because of the emergence of resistant strains of the tubercle bacillus (see below). In the UK recently there have been serious outbreaks in a handful of urban-based schools.... tuberculosis

A rare, noncancerous tumour of the meninges of the brain that arises from the arachnoid mater (middle layer) and usually becomes attached to the dura mater (outer layer). The tumour slowly expands and may become very large before any symptoms appear. Symptoms can include headache, vomiting, and impaired mental function.

There may also be speech loss or visual disturbance. If the tumour invades the skull bone, there may be thickening and bulging of the skull.

Meningiomas can be detected by X-ray or CT scanning, and MRI of the skull, and can often be completely removed by surgery. Otherwise, treatment is by radiotherapy.... meningioma

The major organ of the nervous system, located in the cranium (skull). The brain receives, sorts, and interprets sensations from the nerves that extend from the central nervous system (brain and spinal cord) to the rest of the body; it initiates and coordinates nerve signals involved in activities such as speech, movement, thought, and emotion.

An adult brain weighs about 1.4 kg and has 3 main structures: the largest part, the cerebrum, consisting of left and right hemispheres; the brainstem; and the cerebellum. Each hemisphere in the

cerebrum has an outer layer called the cortex, consisting of grey matter, which is rich in nerve-cell bodies and is the main region for conscious thought, sensation, and movement. Beneath the cortex are tracts of nerve fibres called white matter, and, deeper within the hemispheres, the basal ganglia. The surface of each hemisphere is divided by fissures (sulci) and folds (gyri) into distinct lobes (occipital, frontal, parietal, and temporal lobes), named after the skull bones that overlie them. A thick band of nerve fibres called the corpus callosum connects the hemispheres.

The cerebrum encloses a central group of structures that includes the thalami and the hypothalamus, which has close connections with the pituitary gland. Encircling the thalami is a complex of nerve centres called the limbic system. These structures act as links between parts of the cerebrum and the brainstem lying beneath the thalami.

The brainstem is concerned mainly with the control of vital functions such as breathing and blood pressure. The cerebellum at the back of the brain controls balance, posture, and muscular coordination. Both of these regions operate at a subconscious level.

The brain and spinal cord are encased in 3 layers of membranes, known as meninges.

Cerebrospinal fluid circulates between the layers and within the 4 main brain cavities called ventricles.

This fluid helps to nourish and cushion the brain.

The brain receives about 20 per cent of the blood from the heart’s output.... brain

A cylinder of nerve tissue that runs from the brain, down the central canal in the spine to the 1st lumbar vertebra. Below that, the nerve roots continue within the canal as cauda equina.

Grey matter, the spinal cord’s core, contains the cell bodies of nerve cells. Areas of white matter (tracts of nerve fibres running lengthwise) surround the grey matter. Sprouting from the cord on each side at regular intervals are the sensory and motor spinal nerve roots. The small nodule (ganglion) in each sensory root comprises nerve cell bodies. Nerve roots combine to form the spinal nerves that link the spinal cord to all regions of the trunk and limbs. The entire spinal cord is bathed in cerebrospinal fluid and surrounded by the meninges.

The nerve tracts in the white matter act mainly as highways for sensory information passing up to the brain or motor signals passing down. However, the cord processes some sensory information itself and provides motor responses without involving the brain. Many reflex actions are controlled in this way.

The spinal cord may be injured by trauma (see spinal injury); spinal-cord infections such as poliomyelitis are rare but can cause serious damage.spinal fusion Major surgery to join 2 or more adjacent vertebrae. It is performed if abnormal movement between adjacent vertebrae causes severe back pain or may damage the spinal cord. spinal injury Damage to the spine and sometimes to the spinal cord. Spinal injury is most often the result of falling from a height or of a road traffic accident. Damage to the vertebrae and their ligaments usually causes severe pain and swelling of the affected area. Damage to the spinal cord results in paralysis and/or loss of sensation below the site of injury.

X-rays of the spine are carried out to determine the extent of damage. If the bones are dislocated, surgery is needed to manipulate them back into position. Treatment with the drug methylprednisolone within a few hours of an injury aids recovery from spinal-cord damage. Surgery may be needed to remove any pressure on the cord, but damaged nerve tracts cannot be repaired. Physiotherapy may stop joints locking and muscles contracting as the result of paralysis.

If there is no spinal-cord damage, recovery is usually complete.

In cases of spinal-cord damage, some improvement may occur for up to 12 months.... spinal cord

Cryptococcosis is a rare disease due to infection with a yeast known as Cryptococcus neoformans. Around 5–10 cases are diagnosed annually in the United Kingdom. It usually involves the lungs in the ?rst instance, but may spread to the MENINGES and other parts of the body, including the skin. As a rule, the disease responds well to treatment with AMPHOTERICIN B, clotrimazole, and ?ucytosine.... cryptococcosis

A protrusion of the MENINGES of the spinal cord through a defect in the spine. (See SPINA BIFIDA.)... meningomyelocele

An antituberculous drug used in combination, usually with RIFAMPICIN and ISONIAZID, as the treatment regime for TUBERCULOSIS. It penetrates the MENINGES so is valuable in treating tuberculous MENINGITIS. The drug is sometimes associated with liver damage and liver function tests should be done before using it.... pyrazinamide

Radiculopathy is damage to the roots of nerves where they enter or leave the SPINAL CORD. Causes include ARTHRITIS of the spine, thickening of the MENINGES, and DIABETES MELLITUS. Symptoms include pain, PARAESTHESIA, numbness and wasting of muscles supplied by the nerves. Treatment is of the underlying cause.... radiculopathy

The middle of the 3 layers of membrane (meninges) that cover the brain.... arachnoid mater

A term applied to narrow cavities of various kinds, occurring naturally in the body, or resulting from disease. Thus it is applied to the air-containing cavities which are found in the frontal, ethmoidal, sphenoidal and maxillary bones of the SKULL, and which communicate with the NOSE. The function of these paranasal sinuses, as they are known, is doubtful, but they do lighten the skull and add resonance to the voice. They enlarge considerably around puberty and in this way are a factor in the alteration of the size and shape of the face. The term is also used in connection with the wide spaces through which the blood circulates in the membranes (MENINGES) of the BRAIN. Cavities which are produced when an ABSCESS has burst, but remain unhealed, are also known as sinuses (see also FISTULA).... sinus

This is one of the most common of the congenital (present at birth) malformations. It is one of the three types of neural-tube anomaly, the other two being ANENCEPHALY and cranium bi?dum. It takes two main forms – spina bi?da occulta being much the commoner. There is a de?cit in the posterior part of the SPINAL COLUMN, usually in the LUMBAR region, and it is generally asymptomatic unless the underlying spinal cord is affected. Occasionally it is associated with a hairy patch or birthmark on the back, and a few children develop a mild spastic gait or bladder problems.

Much more serious is spina bi?da cystica, in which the spinal-wall defect is accompanied by a protrusion of the spinal cord. This may take two forms: a meningocele, in which the MENINGES, containing CEREBROSPINAL FLUID, protrude through the defect; and a meningomyelocele, in which the protrusion contains spinal cord and nerves.

Meningocele is less common and has a good prognosis. HYDROCEPHALUS and neurological problems affecting the legs are rare, although the bladder may be affected. Treatment consists of surgery which may be in the ?rst few days of life or much later depending upon the precise situation; long-term follow-up is necessary to pick up any neurological problems that may develop during subsequent growth of the spine.

Meningomyelocele is much more serious and more common, accounting for 90 per cent of all cases. Usually affecting the lumbo-sacral region, the range of severity may vary considerably and, while early surgery with careful attention in a minor case may achieve good mobility, normal bladder function and intellect, a more extensive protrusion may cause complete ANAESTHESIA of the skin, with increased risk of trauma; extensive paralysis of the trunk and limbs, with severe deformities; and paralysis and insensitivity of the bladder and bowel. Involuntary movements may be present, and hydrocephalus occurs in 80 per cent of cases. The decision to operate can only be made after a full examination of the infant to determine the extent of the defect and any co-existent congenital abnormalities. The child’s potential can then be estimated, and appropriate treatment discussed with the parents. Carefully selected patients should receive long-term treatment in a special centre, where full attention can be paid to all their various problems.

There is growing evidence of the value of vitamin supplements before and during pregnancy in reducing the incidence of spina bi?da. Parents of affected infants may obtain help, advice, and encouragement from the Association for Spina Bi?da and Hydrocephalus which has branches throughout the country, or the Scottish Spina Bi?da Association.... spina bifida

A clear, watery fluid that circulates between the ventricles (cavities) within the brain, the central canal in the spinal cord, and the space between the brain and spinal cord and their protective coverings, the meninges.

Cerebrospinal fluid functions as a shockabsorber, helping to prevent or reduce damage to the brain and spinal cord after a blow to the head or back.

It contains glucose, proteins, salts, and white blood cells.

Examination of the fluid, usually obtained by lumbar puncture, is used to diagnose disorders such as meningitis.... cerebrospinal fluid

A protrusion of the spinal cord and its meninges (protective membranes) under the skin due to a congenital defect (see neural tube defect).... myelomeningocele

The innermost of the 3 membranes of the meninges.... pia mater

A break in 1 or more of the skull bones caused by a head injury. In most skull fractures, the broken bones are not displaced and there are no complications. Severe injury may result in bone fragments rupturing blood vessels in the meninges, or, more rarely, tearing the meninges, leading to brain damage.

A fracture without complications usually heals by itself; damage to brain structures often requires neurosurgery.... skull, fracture of

Inflammation of the brain, and sometimes also the meninges, usually due to a viral infection. Encephalitis varies in severity from mild, in which symptoms are barely noticeable, to serious and potentially life-threatening. Mild cases can be due to glandular fever (see infectious mononucleosis) or may be a complication of childhood diseases such as mumps or measles. The most common cause of life-threatening encephalitis is herpes simplex, particularly in people with HIV.

Mild cases usually develop over several days and may cause only a slight fever and mild headache. In serious cases, symptoms develop rapidly and include weakness or paralysis, speech, memory, and hearing problems, and gradual loss of consciousness; coma and seizures may also occur. If the meninges are inflamed, other symptoms may develop, such as a stiff neck and abnormal sensitivity to light.

Diagnosis is based on results of blood tests, CT scanning or MRI, EEG, lumbar puncture, and, rarely, a brain biopsy. Encephalitis due to herpes simplex is treated with intravenous infusion of the antiviral drug aciclovir, but there is no known treatment for encephalitis caused by other viral infections.... encephalitis

Bleeding into the space between the inner surface of the skull and the external surface of the dura mater, the outer layer of the meninges. Extradural haemorrhage usually results from a blow to the side of the head that fractures the skull and ruptures an artery running over the surface of the dura mater. A haematoma (collection of clotted blood) forms and enlarges, causing an increase in pressure inside the skull and resulting in symptoms several hours or even days after the injury. Symptoms may include headache, drowsiness, vomiting, paralysis affecting one side of the body, and seizures. Untreated, extradural haemorrhage may be life-threatening.

CT scanning or MRI confirms the diagnosis.

Surgical treatment consists of craniotomy, draining the blood clot, and clipping the ruptured blood vessel.... extradural haemorrhage

A developmental failure affecting the spinal cord or brain of the embryo. The most serious defect is anencephaly (total lack of a brain), which is fatal. More common is spina bifida, in which the vertebrae do not form a complete ring around the spinal cord. Spina bifida can occur anywhere on the spine, but it is most common in the lower back.

There are different forms of spina bifida. In spina bifida occulta, the only defect is a failure of the fusion of the bony arches behind the spinal cord, which may not cause any problems. When the bone defect is more extensive, there may be a meningocele, a protrusion of the meninges, or a myelomeningocele, a malformation of the spinal cord. Myelomeningocele is likely to cause severe handicap, with paralysis of the legs, loss of sensation in the lower body, hydrocephalus, and paralysis of the anus and bladder, causing incontinence. Associated problems include cerebral palsy, epilepsy, and mental handicap.

Surgery is usually performed a few days after birth. In mild cases, the defect can usually be corrected, but in myelomeningocele, some handicap will remain.

Genetic factors play a part in neural tube defects, which show multifactorial inheritance. Couples who have had an affected child or who have a family history of neural tube defects should seek genetic counselling. The risk of a neural tube defect occurring can be substantially reduced if the mother takes folic acid supplements for a month before conception and during the early part of the pregnancy.

Ultrasound scanning and amniocentesis allow accurate antenatal testing for neural tube defects.... neural tube defect

n. partial or complete absence of the bones of the rear of the skull, the meninges, and the cerebral hemispheres of the brain. It occurs as a developmental defect, and most affected infants are stillborn; if born live they do not survive for more than a few hours. Anencephaly is often associated with other defects of the nervous system, such as *spina bifida. Prenatal screening tests for anencephaly include detection of alpha-fetoprotein levels and ultrasound scanning.... anencephaly

(arachnoid mater) n. the middle of the three membranes covering the brain and spinal cord (see meninges), which has a fine, almost cobweb-like, texture. Between it and the pia mater within lies the subarachnoid space, containing cerebrospinal fluid and large blood vessels; the membrane itself has no blood supply.... arachnoid

The specialty concerned with the surgical treatment of disorders of the brain, spinal cord, or other parts of the nervous system.

Conditions treated by neurosurgery include tumours of the brain, spinal cord, or meninges (membranes surrounding the brain and spinal cord); brain abscess; abnormalities of the blood vessels supplying the brain, such as an aneurysm (balloon-like swelling at a weak point in an artery); bleeding inside the skull (see extradural haemorrhage, intracerebral haemorrhage, and subdural haemorrhage); some birth defects (such as neural tube defects and hydrocephalus); certain types of epilepsy; and nerve damage caused by illness or accidents.

Neurosurgery may also be performed to relieve pain that is otherwise untreatable.... neurosurgery

One of the 5 senses. In the nose, hair-like projections from smell receptor cells lie in the mucous membrane. When the receptors are stimulated by certain molecules, they transmit impulses along the olfactory nerves to the smell centres in the limbic system and frontal lobes of the brain, where smell is perceived.

Possible causes of loss of the sense of smell include inflammation of the nasal membrane, as in a common cold; cigarette smoking; hypertrophic rhinitis,in which thickening of the mucous membrane obscures olfactory nerve endings; atrophic rhinitis, in which the nerves waste away; head injury that tears the nerves; or a tumour of the meninges or nasopharynx. The perception of illusory, unpleasant odours may be a feature of depression, schizophrenia, some forms of epilepsy, or alcohol withdrawal. smelling salts A preparation of ammonia that was used in the past to revive a person who felt faint.... smell

Bleeding into the space between the outer and middle layers of the meninges, usually following head injury. The trapped blood slowly forms a large clot within the skull that presses on brain tissue. The symptoms, which tend to fluctuate, may include headache, confusion, drowsiness, and one-sided weakness or paralysis. The interval between the injury and the start of symptoms varies from days to months. Diagnosis is by CT scanning or MRI. In many cases, surgical treatment is needed. This involves drilling burr holes in the skull (see craniotomy), so that the blood can be drained out and damaged blood vessels repaired. If treatment is carried out at an early enough stage, the person usually makes a full recovery. A subdural haemorrhage that is small and produces few symptoms may not require any treatment. The affected

person is usually monitored with regular scans, and the clot may clear up on its own. (See also extradural haemorrhage.)... subdural haemorrhage

a sign present when there is irritation of the meninges (the membranes covering the brain); it is present in meningitis. As the neck is pulled forward, the hips and knees bend involuntarily. [J. von Brudzinski (1874–1917), Polish physician]... brudzinski sign

any disorder of the blood vessels of the brain and its covering membranes (meninges). Most cases are due to atheroma and/or hypertension, clinical effects being caused by rupture of diseased blood vessels (*cerebral or *subarachnoid haemorrhage) or inadequacy of the blood supply to the brain (ischaemia), due to cerebral thrombosis or embolism. The term cerebrovascular accident is given to the clinical syndrome accompanying a sudden and sometimes severe attack, which leads to a *stroke.... cerebrovascular disease

n. a genus of Gram-negative anaerobic rod-shaped bacteria widely distributed in nature. The organisms cause infections of the intestinal and urinary tracts, gall bladder, and the meninges that are usually secondary, occurring in the elderly, newborn, debilitated, and immunocompromised.... citrobacter

n. 1. surgical removal of a portion of the skull (cranium), performed to expose the brain and *meninges for inspection or biopsy or to relieve excessive intracranial pressure (as in a subdural *haematoma). 2. surgical perforation of the skull of a dead fetus during difficult labour, so that delivery may continue. For both operations the instrument used is called a craniotome.... craniotomy

n. a localized collection of pus and necrotic tissue anywhere in the body, surrounded and walled off by damaged and inflamed tissues. A *boil is an example of an abscess within the skin. The usual cause is local bacterial infection, often by staphylococci, that the body’s defences have failed to overcome. In a cold abscess, due to tubercle bacilli, there is swelling, but little pain or inflammation (as in acute abscesses). Antibiotics, aided by surgical incision to release pus where necessary, are the usual forms of treatment.

The brain and its meninges have a low resistance to infection and a cerebral abscess is liable to follow any penetration of these by microorganisms. The condition is fatal unless relieved by aspiration or surgical drainage.... abscess

(dura mater, pachymeninx) n. the thickest and outermost of the three *meninges surrounding the brain and spinal cord. It consists of two closely adherent layers, the outer of which is identical with the periosteum of the skull. The inner dura extends downwards between the cerebral hemispheres to form the falx cerebri and forwards between the cerebrum and cerebellum to form the tentorium. A thin film of fluid (not cerebrospinal fluid) separates the inner dura from the arachnoid.... dura

n. any tumour arising from or resembling endothelium. It may arise from the linings of blood or lymph vessels (haemangioendothelioma and lymphangioendothelioma respectively); from the linings of the pleural cavity or the peritoneal cavity (see mesothelioma); or from the meninges (see meningioma).... endothelioma

(Lindau’s tumour) n. a tumour of the brain or spinal cord arising in the blood vessels of the meninges or brain. It is often associated with *phaeochromocytoma and *syringomyelia. See also von Hippel-Lindau disease.... haemangioblastoma

pl. n. the inner two *meninges: the arachnoid and pia mater.... leptomeninges

(meningo-) combining form denoting the meninges.... mening

adj. relating to or affecting the meninges covering the brain and spinal cord and the blood vessels that penetrate them to supply the underlying neural tissues. The term is also used to describe tertiary syphilitic infection of the nervous system.... meningovascular

n. 1. the thin layer of mesoderm that surrounds the brain of the embryo. It gives rise to most of the skull and the membranes that surround the brain. See also chondrocranium. 2. see meninges.... meninx

a group of congenital abnormalities caused by failure of the *neural tube to form normally. In *spina bifida the bony arches of the spine, which protect the spinal cord and its coverings (the meninges), fail to close. More severe defects of fusion of these bones will result in increasingly serious neurological conditions. A meningocele is the protrusion of the meninges through the gap in the spine, the skin covering being vestigial. There is a constant risk of damage to the meninges, with resulting infection. Urgent surgical treatment to protect the meninges is therefore required. In a meningomyelocele (myelomeningocele, myelocele) the spinal cord and the nerve roots are exposed, often adhering to the fine membrane that overlies them. There is a constant risk of infection and this condition is accompanied by paralysis and numbness of the legs and urinary incontinence. *Hydrocephalus and an *Arnold–Chiari malformation are usually present. A failure of fusion at the cranial end of the neural tube (cranium bifidum) gives rise to comparable disorders. The bone defect is most often in the occipital region of the skull but it may occur in the frontal or basal regions. A protrusion of the meninges alone is known as a cranial meningocele. The terms meningoencephalocele, encephalocele, and cephalocele are used for the protrusion of brain tissue through the skull defect. This is accompanied by severe mental and physical disorders.... neural tube defects

n. inflammation of the dura mater, one of the membranes (meninges) covering the brain and spinal cord (see meningitis).... pachymeningitis

n. the *dura mater, outermost of the three meninges.... pachymeninx

(pia mater) n. the innermost of the three *meninges surrounding the brain and spinal cord. The membrane is closely attached to the surface of the brain and spinal cord, faithfully following each fissure and sulcus. It contains numerous finely branching blood vessels that supply the nerve tissue within. The subarachnoid space separates it from the arachnoid.

pian n. see yaws.... pia

n. a tumour containing gritty sandlike particles (psammoma bodies). It is typical of cancer of the ovary but may also be found in the meninges (the membranes surrounding the brain).... psammoma

an influenza-like viral disease that affects the brain and nervous system and occurs in Russia and central Europe. It is transmitted to humans either through the bite of forest-dwelling ticks of the species Ixodes persulcatus or by drinking the milk of infected goats. Infection of the meninges results in paralysis of the limbs and of the muscles of the neck and back. The disease, which is often fatal, can be prevented by vaccination.... russian spring-summer encephalitis

the fifth and largest *cranial nerve (V), which is split into three main branches: ophthalmic, maxillary, and mandibular (see illustration). The motor fibres are responsible for controlling the muscles involved in chewing, while the sensory fibres relay information about temperature, pain, and touch from the whole front half of the head (including the mouth) and also from the meninges.... trigeminal nerve