An unconscious person can be roused only with difficulty or not at all.
Unconsciousness may be brief and light, as in fainting, or deep and prolonged (see coma).
Unconsciousness may be temporary, prolonged or inde?nite (see PERSISTENT VEGETATIVE STATE (PVS)), depending upon the severity of the initiating incident. The patient’s recovery depends upon the cause and success of treatment, where given. MEMORY may be affected, as may motor and sensory functions; but short periods of unconsciousness as a result, say, of trauma have little obvious e?ect on brain function. Repeated bouts of unconsciousness (which can happen in boxing) may, however, have a cumulatively damaging e?ect, as can be seen on CT (COMPUTED TOMOGRAPHY) scans of the brain.
POISONS such as CARBON MONOXIDE (CO), drug overdose, a fall in the oxygen content of blood (HYPOXIA) in lung or heart disease, or liver or kidney failure harm the normal chemical working or metabolism of nerve cells. Severe blood loss will cause ANOXIA of the brain. Any of these can result in altered brain function in which impairment of consciousness is a vital sign.
Sudden altered consciousness will also result from fainting attacks (syncope) in which the blood pressure falls and the circulation of oxygen is thereby reduced. Similarly an epileptic ?t causes partial or complete loss of consciousness by causing an abrupt but temporary disruption of the electrical activity in the nerve cells in the brain (see EPILEPSY).
In these events, as the brain’s function progressively fails, drowsiness, stupor and ?nally COMA ensue. If the cause is removed (or when the patient spontaneously recovers from a ?t or faint), normal consciousness is usually quickly regained. Strokes (see STROKE) are sometimes accompanied by a loss of consciousness; this may be immediate or come on slowly, depending upon the cause or site of the strokes.
Comatose patients are graded according to agreed test scales – for example, the GLASGOW COMA SCALE – in which the patient’s response to a series of tests indicate numerically the level of coma.
Treatment of unconscious patients depends upon the cause, and range from ?rst-aid care for someone who has fainted to hospital intensive-care treatment for a victim of a severe head injury or massive stroke.
The speciality of anaesthesia broadly covers its provision for SURGERY, intensive therapy (intensive care), chronic pain management, acute pain management and obstetric analgesia. Anaesthetists in Britain are trained specialists with a medical degree, but in many countries some anaesthetists may be nurse practitioners working under the supervision of a medical anaesthetist.
The anaesthetist will assess the patient’s ?tness for anaesthesia, choose and perform the appropriate type of anaesthetic while monitoring and caring for the patient’s well-being, and, after the anaesthetic, supervise recovery and the provision of post-operative pain relief.
Anaesthesia may be broadly divided into general and local anaesthesia. Quite commonly the two are combined to allow continued relief of pain at the operation site after the patient awakens.
General anaesthesia is most often produced by using a combination of drugs to induce a state of reversible UNCONSCIOUSNESS. ‘Balanced’ anaesthesia uses a combination of drugs to provide unconsciousness, analgesia, and a greater or lesser degree of muscle relaxation.
A general anaesthetic comprises induction, maintenance and recovery. Historically, anaesthesia has been divided into four stages (see below), but these are only clearly seen during induction and maintenance of anaesthesia using inhalational agents alone.
(1) Onset of induction to unconsciousness
(2) Stage of excitement
(3) Surgical anaesthesia
(4) Overdosage
Induction involves the initial production of unconsciousness. Most often this is by INTRAVENOUS injection of a short-acting anaesthetic agent such as PROPOFOL, THIOPENTONE or ETOMIDATE, often accompanied by additional drugs such as ANALGESICS to smooth the process. Alternatively an inhalational technique may be used.
Maintenance of anaesthesia may be provided by continuous or intermittent use of intravenous drugs, but is commonly provided by administration of OXYGEN and NITROUS OXIDE or air containing a volatile anaesthetic agent. Anaesthetic machines are capable of providing a constant concentration of these, and have fail-safe mechanisms and monitors which guard against the patient’s receiving a gas mixture with inadequate oxygen (see HYPOXIC). The gases are adminstered to the patient via a breathing circuit either through a mask, a laryngeal mask or via ENDOTRACHEAL INTUBATION. In recent years, concerns about side-effects and pollution caused by volatile agents have led to increased popularity of total intravenous anaesthesia (TIVA).
For some types of surgery the patient is paralysed using muscle relaxants and then arti?cially ventilated by machine (see VENTILATOR). Patients are closely monitored during anaesthesia by the anaesthetist using a variety of devices. Minimal monitoring includes ELECTROCARDIOGRAM (ECG), blood pressure, PULSE OXIMETRY, inspired oxygen and end-tidal carbon-dioxide concentration – the amount of carbon dioxide breathed out when the lungs are at the ‘empty’ stage of the breathing cycle. Analgesic drugs (pain relievers) and local or regional anaesthetic blocks are often given to supplement general anaesthesia.
Volatile anaesthetics are either halogenated hydrocarbons (see HALOTHANE) or halogenated ethers (iso?urane, en?urane, des?urane and sevo?urane). The latter two are the most recently introduced agents, and produce the most rapid induction and recovery – though on a worldwide basis halothane, ether and chloroform are still widely used.
Despite several theories, the mode of action of these agents is not fully understood. Their e?cacy is related to how well they dissolve into the LIPID substances in nerve cells, and it is thought that they act at more than one site within brain cells – probably at the cell membrane. By whatever method, they reversibly depress the conduction of impulses within the CENTRAL NERVOUS SYSTEM and thereby produce unconsciousness.
At the end of surgery any muscle relaxant still in the patient’s body is reversed, the volatile agent is turned o? and the patient breathes oxygen or oxygen-enriched air. This is the reversal or recovery phase of anaesthesia. Once the anaesthetist is satis?ed with the degree of recovery, patients are transferred to a recovery area within the operating-theatre complex where they are cared for by specialist sta?, under the supervision of an anaesthetist, until they are ready to return to the ward. (See also ARTIFICIAL VENTILATION OF THE LUNGS.) Local anaesthetics are drugs which reversibly block the conduction of impulses in nerves. They therefore produce anaesthesia (and muscle relaxation) only in those areas of the body served by the nerve(s) affected by these drugs. Many drugs have some local anaesthetic action but the drugs used speci?cally for this purpose are all amide or ester derivatives of aromatic acids. Variations in the basic structure produce drugs with di?erent speeds of onset, duration of action and preferential SENSORY rather than MOTOR blockade (stopping the activity in the sensory or motor nerves respectively).
The use of local rather than general anaesthesia will depend on the type of surgery and in some cases the unsuitability of the patient for general anaesthesia. It is also used to supplement general anaesthesia, relieve pain in labour (see under PREGNANCY AND LABOUR) and in the treatment of pain in persons not undergoing surgery. Several commonly used techniques are listed below:
LOCAL INFILTRATION An area of anaesthetised skin or tissue is produced by injecting local anaesthetic around it. This technique is used for removing small super?cial lesions or anaesthetising surgical incisions.
NERVE BLOCKS Local anaesthetic is injected close to a nerve or nerve plexus, often using a peripheral nerve stimulator to identify the correct point. The anaesthetic di?uses into the nerve, blocking it and producing anaesthesia in the area supplied by it.
SPINAL ANAESTHESIA Small volumes of local anaesthetic are injected into the cerebrospinal ?uid through a small-bore needle which has been inserted through the tissues of the back and the dura mater (the outer membrane surrounding the spinal cord). A dense motor and sensory blockade is produced in the lower half of the body. How high up in the body it reaches is dependent on the volume and dose of anaesthetic, the patient’s position and individual variation. If the block is too high, then respiratory-muscle paralysis and therefore respiratory arrest may occur. HYPOTENSION (low blood pressure) may occur because of peripheral vasodilation caused by sympathetic-nerve blockade. Occasionally spinal anaesthesia is complicated by a headache, perhaps caused by continuing leakage of cerebrospinal ?uid from the dural puncture point.
EPIDURAL ANAESTHESIA Spinal nerves are blocked in the epidural space with local anaesthetic injected through a ?ne plastic tube (catheter) which is introduced into the space using a special needle (Tuohy needle). It can be used as a continuous technique either by intermittent injections, an infusion or by patient-controlled pump. This makes it ideal for surgery in the lower part of the body, the relief of pain in labour and for post-operative analgesia. Complications include hypotension, spinal headache (less than 1:100), poor e?cacy, nerve damage (1:12,000) and spinal-cord compression from CLOT or ABSCESS (extremely rare).... anaesthesia
Symptoms. Sudden drawing-up of knees, nausea, vomiting, pallor, shallow breathing, prostration, weak heart beat, irritability, amnesia.
Treatment. Bed rest. Protection of eyes against light. Admission to hospital in case of deep brain damage. Quietness. Tranquillisers, sedatives and alcohol aggravate symptoms. If patient can swallow, alternatives as follows:–
Teas. St John’s Wort (concussion of the spine). Skullcap (to ease headache). Ginkgo (cerebral damage). Powders. Formula. Combine, St John’s Wort 3; Skullcap 2; Oats 2; Trace of Cayenne. Dose: 750mg (three 00 capsules or half a teaspoon) two-hourly.
Tinctures. Formula as above, but with few drops Tincture Capsicum in place of Cayenne powder: 1-2 teaspoons in water hourly.
Tincture Arnica. (European practise) 2-5 drops in hot water usually sufficient to hasten recovery.
Topical. Distilled Extract Witch Hazel saturated pad over eyes and to wipe forehead.
Supplements. Vitamin B-complex. B6, C. ... concussion
Three forms: major (grand mal); temporal lobe; and minor (petit mal). In petit mal the period of unconsciousness consists of brief absences lasting less than 15 seconds.
Treatment. Orthodox medical: Carbamazepine, phenytoin and many other drugs.
Alternatives. BHP (1983) recommends: Grand mal: Passion flower, Skullcap, Verbena. Petit mal: Hyssop. Standard central nervous system relaxants are Hops, Lobelia, Passion flower, Vervain, Valerian, Skullcap. Wm Boericke used Mugwort. Peony leaf tea had a long traditional use. In nearly all epileptics there is functional heart disturbance (Hawthorn, Lily of the Valley, Motherwort). Mistletoe can help in the struggle to control seizures and improve the quality of life.
Two important remedies are Skullcap and Passion flower. Both work quickly without risk of respiratory arrest. If dose by mouth is not possible insert gelatin capsules containing powders, per rectum, child or adult lying prone. This method is particularly suitable for feverish convulsions or Grand mal.
Repeat after 5 minutes if patient continues in convulsion. Where neither of these powders are available, Chamomile, Valerian or Mistletoe may be used.
“The remedy I have relied on most,” writes C.I. Reid, MD (Ellingwood’s Journal) “is Passion flower. Use this alone or in combination with Gelsemium – more often alone. I cannot say I obtain an absolutely curative effect, but the spasms disappear and do not return while the remedy is continued. It has none of the unpleasant effects of other medicines. I give the liquid extract in doses from 25-30 drops, 3-4 times daily, for continued use. It may be given more frequently for convulsions.”
Alfred Dawes, MNIMH. Green tincture of Mistletoe, 3-5 drops. Or, combine equal parts: Liquid Extract Skullcap, Valerian and Black Horehound.
Finlay Ellingwood MD combines White Bryony, Prickly Ash, Skullcap and St John’s Wort.
Samuel Thomson MD. Lobelia 2; Cayenne 1; (antispasmodic drops) given at the premonitary stage. 1-2 teaspoons.
Edgar Cayce. Passion flower tea. Hot Castor oil packs.
Excess acidity and intestinal toxaemia. There is considerable opinion that these trigger an attack. Combination: Liquid Extracts – Skullcap 15ml; Mistletoe 10ml; Meadowsweet 10ml; Elderflowers 10ml. Two 5ml teaspoons in water thrice daily.
West African Black Pepper. (Piper guineense) is used by traditional Nigerian healers to good effect. Associated with imperfect menstruation. Liquid Extracts, single or in combination: Black Cohosh, Life root, Lobelia. Dose: 5-15 drops thrice daily.
Associated with mental weakness. Liquid Extract Oats (avena sativa). 2-3 teaspoons in water thrice daily.
Aromatherapy. (Complex partial seizures) Massage with essential oils found to be beneficial. (The Lancet, 1990, 336 (8723) 1120)
Diet. Salt-free lacto-vegetarian. Oatmeal porridge. A cleansing 8-day grape juice fast has its advocates. Vitamin E. In 24 epileptic children refractory to anti-epileptic drugs (AEDs) with generalised tonic- clonic and other types of seizures, addition of Vitamin E 400iu daily to existing AEDs was accompanied by a significant reduction in 10 of 12 cases. (Epilepsy 1989; 30(1): 84-89)
Supportives: osteopathic or chiropractic adjustments.
Note: A number of Italian physicians linked a salt-rich diet with epileptic fits. Number and violence diminished when discontinued and did not recur for weeks. Dr W.P. Best found that, in children, circumcism made a valuable contribution.
Drug-dependency. Herbal medication may offer a supportive role to primary medical treatment. Under no circumstances should sufferers discontinue basic orthodox treatments except upon the advice of a physician.
Information. British Epilepsy Association, 40 Hanover Square, Leeds LS3 1BE, UK. Send SAE.
To be treated by or in liaison with a qualified medical practitioner. ... epilepsy
Severe head injuries cause unconsciousness for hours or many days, followed by loss of memory before and after that period of unconsciousness. The skull may be fractured; there may be ?ts in the ?rst week; and there may develop a blood clot in the brain (intracerebral haematoma) or within the membranes covering the brain (extradural and subdural haematomata). These clots compress the brain, and the pressure inside the skull – intracranial pressure – rises with urgent, life-threatening consequences. They are identi?ed by neurologists and neurosurgeons, con?rmed by brain scans (see COMPUTED TOMOGRAPHY; MRI), and require urgent surgical removal. Recovery may be complete, or in very severe cases can be marred by physical disabilities, EPILEPSY, and by changes in intelligence, rational judgement and behaviour. Symptoms generally improve in the ?rst two years.
A minority of those with minor head injuries have complaints and disabilities which seem disproportionate to the injury sustained. Referred to as the post-traumatic syndrome, this is not a diagnostic entity. The complaints are headaches, forgetfulness, irritability, slowness, poor concentration, fatigue, dizziness (usually not vertigo), intolerance of alcohol, light and noise, loss of interests and initiative, DEPRESSION, anxiety, and impaired LIBIDO. Reassurance and return to light work help these symptoms to disappear, in most cases within three months. Psychological illness and unresolved compensation-claims feature in many with implacable complaints.
People who have had brain injuries, and their relatives, can obtain help and advice from Headwat and from www.neuro.pmr.vcu.edu and www.biausa.org... brain injuries
Causes The most common reason for convulsions is EPILEPSY, and the underlying cause of the latter often remains uncertain. In newborns, convulsions may be due to HYPOXIA following a di?cult labour, or to low levels of sugar or calcium in the blood (HYPOGLYCAEMIA; HYPOCALCAEMIA). A sudden rise of body temperature during infective illness may induce convulsions in an infant or young child.
Diseases of the brain, such as meningitis, encephalitis and tumours, or any disturbance of the brain due to bleeding, blockage of a blood vessel, or irritation of the brain by a fracture of the skull, may also be responsible for convulsions (see BRAIN, DISEASES OF).
Asphyxia, for example from choking, may also bring on convulsions.
Treatment Newborns with hypoglycaemia or hypocalcaemia are treated by replacing the missing compound. Infants with febrile convulsions may be sponged with tepid water and fever reduced with paracetamol.
In epilepsy, unless it is particularly severe, the movements seldom need to be restrained. If convulsions persist beyond a few minutes it may be necessary to give BENZODIAZEPINES, either intravenously or rectally. In the UK, paramedics are trained to do this; likewise many parents of epileptic children are capable of administering the necessary treatment. If however this fails to stop the convulsions immediately, hospital admission is needed for further treatment. Once ?ts are under control, the cause of the convulsions must be sought and the necessary long-term treatment given.... convulsions
Hyperventilation is a manifestation of chest and heart diseases which raise carbon dioxide tension or cause HYPOXIA (e.g. severe CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) or PULMONARY OEDEMA). Mechanically ventilated patients may be hyperventilated to lower carbon dioxide tension in order to reduce INTRACRANIAL PRESSURE. (See also HYPOCAPNIA.)... hyperventilation
Each year around 50 people in the United Kingdom are reported as dying from carbon monoxide poisoning, and experts have suggested that as many as 25,000 people a year are exposed to its effects within the home, but most cases are unrecognised, unreported and untreated, even though victims may suffer from long-term effects. This is regrettable, given that Napoleon’s surgeon, Larrey, recognised in the 18th century that soldiers were being poisoned by carbon monoxide when billeted in huts heated by woodburning stoves. In the USA it is estimated that 40,000 people a year attend emergency departments suffering from carbon monoxide poisoning. So prevention is clearly an important element in dealing with what is sometimes termed the ‘silent killer’. Safer designs of houses and heating systems, as well as wider public education on the dangers of carbon monoxide and its sources, are important.
Clinical effects of acute exposure resemble those of atmospheric HYPOXIA. Tissues and organs with high oxygen consumption are affected to a great extent. Common effects include headaches, weakness, fatigue, ?ushing, nausea, vomiting, irritability, dizziness, drowsiness, disorientation, incoordination, visual disturbances, TACHYCARDIA and HYPERVENTILATION. In severe cases drowsiness may progress rapidly to COMA. There may also be metabolic ACIDOSIS, HYPOKALAEMIA, CONVULSIONS, HYPOTENSION, respiratory depression, ECG changes and cardiovascular collapse. Cerebral OEDEMA is common and will lead to severe brain damage and focal neurological signs. Signi?cant abnormalities on physical examination include impaired short-term memory, abnormal Rhomberg’s test (standing unsupported with eyes closed) and unsteadiness of gait including heel-toe walking. Any one of these signs would classify the episode as severe. Victims’ skin may be coloured pink, though this is very rarely seen even in severe incidents. The venous blood may look ‘arterial’. Patients recovering from acute CO poisoning may suffer neurological sequelae including TREMOR, personality changes, memory impairment, visual loss, inability to concentrate and PARKINSONISM. Chronic low-level exposures may result in nausea, fatigue, headache, confusion, VOMITING, DIARRHOEA, abdominal pain and general malaise. They are often misdiagnosed as in?uenza or food poisoning.
First-aid treatment is to remove the victim from the source of exposure, ensure an e?ective airway and give 100-per-cent oxygen by tight-?tting mask. In hospital, management is largely suppportive, with oxygen administration. A blood sample for COHb level determination should be taken as soon as practicable and, if possible, before oxygen is given. Ideally, oxygen therapy should continue until the COHb level falls below 5 per cent. Patients with any history of unconsciousness, a COHb level greater than 20 per cent on arrival, any neurological signs, any cardiac arrhythmias or anyone who is pregnant should be referred for an expert opinion about possible treatment with hyperbaric oxygen, though this remains a controversial therapy. Hyperbaric oxygen therapy shortens the half-life of COHb, increases plasma oxygen transport and reverses the clinical effects resulting from acute exposures. Carbon monoxide is also an environmental poison and a component of cigarette smoke. Normal body COHb levels due to ENDOGENOUS CO production are 0.4 to
0.7 per cent. Non-smokers in urban areas may have level of 1–2 per cent as a result of environmental exposure. Smokers may have a COHb level of 5 to 6 per cent.... carbon monoxide (co)
Symptoms Warning symptoms include dizziness, headache, oedema, vomiting, and the secretion of albumin (protein) in the urine. These are normally accompanied by a rise in blood pressure, which can be severe. Preeclamptic symptoms may be present for some days or weeks before the seizure takes place, and, if a woman is found to have these during antenatal care, preventive measures must be taken. Untreated, CONVULSIONS and unconsciousness are very likely, with serious migraine-like frontal headache and epigastric pain the symptoms.
Treatment Prevention of eclampsia by dealing with pre-eclamptic symptoms is the best management, but even this may not prevent convulsions. Hospital treatment is essential if eclampsia develops, preferably in a specialist unit. The treatment of the seizures is that generally applicable to convulsions of any kind, with appropriate sedatives given such as intravenous DIAZEPAM. HYDRALLAZINE intravenously should also be administered to reduce the blood pressure. Magnesium sulphate given intramuscularly sometimes helps to control the ?ts. The baby’s condition should be monitored throughout.
Urgent delivery of the baby, if necessary by CAESAREAN SECTION, is the most e?ective ‘treatment’ for a mother with acute eclampsia. (See PREGNANCY AND LABOUR.)
Women who have suffered from eclampsia are liable to suffer a recurrence in a further preganancy. Careful monitoring is required. There is a self-help organisation, Action on Pre-eclampsia (APEC), to advise on the condition.... eclampsia
– electroencephalograms – are useful in DIAGNOSIS: for example, the abnormal electroencephalogram occurring in EPILEPSY is characteristic of this disease. The normal waves, known as alpha waves, occur with a frequency of 10 per second. Abnormal waves, with a frequency of 7 or fewer per second, are known as delta waves and occur in the region of cerebral tumours and in the brains of epileptics. An electroencephalogram can assess whether an individual is awake, alert or asleep. It may also be used during surgery to monitor the depth of unconsciousness in anaesthetised patients.... electroencephalography (eeg)
As their title shows, A&E departments (and the 999 and 112 telephone lines) are for patients who are genuine emergencies: namely, critical or life-threatening circumstances such as:
unconsciousness.
serious loss of blood.
suspected broken bones.
deep wound(s) such as a knife wound.
suspected heart attack.
di?culty in breathing.
suspected injury to brain, chest or abdominal organs.
•?ts. To help people decide which medical service is most appropriate for them (or someone they are caring for or helping), the following questions should be answered:
Could the symptoms be treated with an overthe-counter (OTC) medicine? If so, visit a pharmacist.
Does the situation seem urgent? If so, call NHS Direct or the GP for telephone advice, and a surgery appointment may be the best action.
Is the injured or ill person an obvious emergency (see above)? If so, go to the local A&E department or call 999 for an ambu
lance, and be ready to give the name of the person involved, a brief description of the emergency and the place where it has occurred.... emergency
Severe hypothermia is sometimes complicated by gastric erosions and haemorrhage, as well as pancreatitis (see PANCREAS, DISORDERS OF). Infants and the elderly are less e?cient at regulating temperature and conserving heat than other age groups, and are therefore more at risk from accidental hypothermia during cold weather if their accommodation is not warm enough. Approximately half a million elderly people are at risk in Britain each winter from hypothermia. The other major cause of accidental hypothermia is near-drowning in icy water. Deliberate hypothermia is sometimes used to reduce metabolic rate so that prolonged periods of cardiac arrest may occur without tissue HYPOXIA developing. This technique is used for some cardiac and neurosurgical operations and is produced by immersion of the anaesthetised patient in iced water or by cooling an extracorporeal circulation.
Treatment of hypothermia is by warming the patient and treating any complications that arise. Passive warming is usual, with conservation of the patient’s own body heat with insulating blankets. If the core temperature is below 28 °C, then active rewarming should be instituted by means of warm peritoneal, gastric or bladder lavage or using an extracorporeal circulation. Care must be taken in moving hypothermic patients, as a sudden rush of cold peripheral blood to the heart can precipitate ventricular ?brillation. Prevention of hypothermia in the elderly is important. Special attention must be paid to diet, heating the home and adequate clothing in several layers to limit heat loss.... hypothermia
During registration, information from the sense organs and the cerebral cortex is put into codes for storage in the short-term memory system. The codes are usually acoustic (based on the sounds and words that would be used to describe the information) but may use any of the ?ve senses. This system can take only a few chunks of information at a time: for example, only about seven longish numbers can be retained and recalled at once – the next new number displaces an earlier one that is then forgotten. And if a subject is asked to describe a person just met, he or she will recall only seven or so facts about that person. This depends on attention span and can be improved by concentration and rehearsal – for example, by reciting the list of things that must be remembered.
Material needing storage for several minutes stays in the short-term memory. More valuable information goes to the long-term memory where it can be kept for any period from a few minutes to a lifetime. Storage is more reliable if the information is in meaningful codes – it is much easier to remember people’s names if their faces and personalities are memorable too. Using techniques such as mnemonics takes this into account.
The ?nal stage is retrieval. Recognising and recalling the required information involves searching the memory. In the short-term memory, this takes about 40-thousandths of a second per item – a rate that is surprisingly consistent, even in people with disorders such as SCHIZOPHRENIA.
Most kinds of forgetting or AMNESIA occur during retrieval. Benign forgetfulness is usually caused by interference from similar items because the required information was not clearly coded and well organised. Retrieval can be improved by recreating the context in which the information was registered. This is why the police reconstruct scenes of crimes, and why revision for exams is more e?ective if facts are learnt in the form of answers to mock questions.
Loss of memory or amnesia mainly affects long-term memory (information which is stored inde?nitely) rather than short-term memory which is measured in minutes. Short-term memory may, however, be affected by unconsciousness caused by trauma. Drivers involved in an accident may be unable to recall the event or the period leading up to it. The cause of amnesia is disease of or damage to the parts of the brain responsible for memory. Degenerative disorders such as ALZHEIMER’S DISEASE, brain tumours, infections (for example, ENCEPHALITIS), STROKE, SUBARACHNOID HAEMORRHAGE and alcoholism all cause memory loss. Some psychiatric illnesses feature loss of memory and AGEING is usually accompanied by some memory loss, although the age of onset and severity vary greatly.... memory
The term is also used to describe any state of heightened awareness, such as that caused by sexual stimulation or fear.
Arousal is regulated by the reticular formation in the brainstem.... arousal
It is prescribed for people who request help for alcohol dependence.
Treatment is usually combined with a counselling programme.
Disulfiram slows down the clearance of alcohol in the body, causing flushing, headache, nausea, dizziness, and palpitations.
Symptoms may start within 10 minutes of drinking alcohol and can last for hours.
Occasionally, large amounts of alcohol taken during treatment can cause unconsciousness; a person taking the drug should carry a warning card.... disulfiram
Abnormal drowsiness may be the result of a head injury, high fever, meningitis, uraemia (excess urea in the blood due to kidney failure), or liver failure.
Alcohol or drugs may also produce this effect.
In a person with diabetes mellitus, drowsiness may be due to hypoglycaemia or to hyperglycaemia.
Abnormal drowsiness should be treated as a medical emergency.... drowsiness
Strangulation of a person’s neck, either with a ligature or with the hands, obstructs the jugular veins in the neck, preventing the normal out?ow of blood from the brain and head. The TRACHEA is also compressed, cutting o? the supply of air to the lungs. The combination of these effects leads to HYPOXIA and damage to the brain. If not quickly relieved, unconsciousness and death follow. Strangulation may be deliberate or accidental – the latter being a particular hazard for children, for example, when playing with a rope. Removal of the constriction, arti?cial respiration, and medical attention are urgently necessary.... strangulation
Trepanning is used in cases of fracture, with splintering of the skull; the operation is performed to remove fragments of bone and any foreign bodies, like a bullet, which may have entered. In compression of the brain with unconsciousness following an injury, the skull is trephined and any blood clots removed, or torn vessels ligatured. The operation may also be done for an ABSCESS within the skull and for other conditions where operative access to the brain is required.... trepanning
The word uraemia means excess UREA in the blood; however, the symptoms of renal failure are not due to the abnormal amounts of urea circulating, but rather to the electrolyte disturbances (see ELECTROLYTES) and ACIDOSIS which are associated with impaired renal function. The acidosis results from a decreased ability to ?lter hydrogen ions from blood into the glomerular ?uid: the reduced production of ammonia and phosphate means fewer ions capable of combining with the hydrogen ions, so that the total acid elimination is diminished. The fall in glomerular ?ltration also leads to retention of SODIUM and water with resulting OEDEMA, and to retention of POTASSIUM resulting in HYPERKALAEMIA.
The most important causes of uraemia are the primary renal diseases of chronic glomerular nephritis (in?ammation) and chronic PYELONEPHRITIS. It may also result from MALIGNANT HYPERTENSION damaging the kidneys and amyloid disease destroying them. Analgesic abuse can cause tubular necrosis. DIABETES MELLITUS may cause a nephropathy and lead to uraemia, as may MYELOMATOSIS and SYSTEMIC LUPUS ERYTHEMATOSUS (SLE). Polycystic kidneys and renal tuberculosis account for a small proportion of cases.
Symptoms Uraemia is sometimes classed as acute – that is, those cases in which the symptoms develop in a few hours or days – and chronic, including cases in which the symptoms are less marked and last over weeks, months, or years. There is, however, no dividing line between the two, for in the chronic variety, which may be said to consist of the symptoms of chronic glomerulonephritis, an acute attack is liable to come on at any time.
Headache in the front or back of the head, accompanied often by insomnia and daytime drowsiness, is one of the most common symptoms. UNCONSCIOUSNESS of a profound type, which may be accompanied by CONVULSIONS resembling those of EPILEPSY, is the most outstanding feature of an acute attack and is a very dangerous condition.
Still another symptom, which often precedes an acute attack, is severe vomiting without apparent cause. The appetite is always poor, and the onset of diarrhoea is a serious sign.
Treatment The treatment of the chronic type of uraemia includes all the measures which should be taken by a person suffering from chronic glomerulonephritis (see under KIDNEYS, DISEASES OF). An increasing number of these patients, especially the younger ones, are treated with DIALYSIS and/or renal TRANSPLANTATION.... uraemia
Ether was the first general anaesthetic.... ether
Alcohol is a drug and produces a wide range of mental and physical effects. The effect of alcohol on the central nervous system is as a depressant, decreasing its activity and thereby reducing anxiety, tension, and inhibitions. In moderate amounts, alcohol produces a feeling of relaxation, confidence, and sociability. However, alcohol slows reactions, and the more that is drunk, the greater is the impairment of concentration and judgement. Excessive consumption of alcohol results in poisoning or acute alcohol intoxication, with effects ranging from euphoria to unconsciousness.
Short-term physical effects of alcohol include peripheral vasodilation (widening of the small blood vessels), which causes the face to flush, and increased flow of gastric juices, which stimulates the appetite. Alcohol increases sexual confidence, but high levels can cause impotence. Alcohol also acts as a diuretic, increasing urine output.
In the long term, regular excessive alcohol consumption can cause gastritis (inflammation and ulceration of the stomach lining), and lead to alcoholrelated disorders.
Heavy drinking in the long term may also lead to alcohol dependence.
However, people who drink regular, small amounts of alcohol (an average of 1–2 units a day) seem to have lower rates of coronary heart disease and stroke than total abstainers.... alcohol
All except the mildest electric shocks may result in unconsciousness. Alternating current (AC) is more dangerous than direct current (DC) because it causes sustained muscle contractions, which may prevent the victim from letting go of the source of the current. A current as small as 0.1 of an amp passing through the heart can cause a fatal arrhythmia. The same current passing through the brainstem may cause the heart to stop beating and breathing to cease. Larger currents, generated by high voltages, may cause charring of tissues, especially where the current enters and exits the body. ... electrical injury
brain is restored. This restoration usually happens within minutes because the loss of consciousness results in the person falling into a lying position, which restores the flow of blood to the brain. Medical attention should be sought for prolonged unconsciousness or repeated attacks of fainting.... fainting
If the head injury is mild, there may only be a slight headache. In some cases there is concussion. More severe head injuries may result in unconsciousness or coma, which may be fatal. Amnesia may occur. After a severe brain injury, there may be some muscular weakness or paralysis and loss of sensation. Symptoms such as persistent vomiting, double vision, or a deteriorating level of consciousness could suggest progressive brain damage.
Investigations may include skull X-rays and CT scanning. A blood clot inside the skull may be life-threatening and requires surgical removal; severe skull fractures may also require surgery. Recovery from concussion may take several days. There may be permanent physical or mental disability if the brain has been damaged. Recovery from a major head injury can be very slow, but there may be signs of progressive improvement for several years after the injury occurred.... head injury
Hypoxia in muscles forces the muscle cells to produce energy anaerobically, which can lead to cramps. Hypoxia in heart muscle may cause angina pectoris. Hypoxia of the brain causes confusion, dizziness, and incoordination, causing unconsciousness and death if persistent. Hypoxia can be assessed by using an oximeter to measure the oxygen concentration of blood in the tissues. Severe hypoxia may require oxygen therapy or artificial ventilation.... hypoxia
Treatment may include washing out the stomach (see lavage, gastric) or removing soiled clothing and washing contaminated skin.
Injections of atropine may be given, and oxygen therapy and/or artificial ventilation may be needed.
With rapid treatment, people may survive doses that would otherwise have been fatal.
Long term effects of organophosphates in sheep dips are thought to be responsible for debilitating illness with neural, muscular, and mental symptoms.... organophosphates
In some affected children, the spleen enlarges and traps red cells at a particularly high rate, causing a life-threatening form of anaemia. After adolescence, the spleen usually stops functioning, increasing the risk of infection in those affected.
Diagnosis is made from examination of a blood smear and electrophoresis.
Supportive treatment may include folic acid supplements, and penicillin and immunization to protect against infection.
Life-threatening crises are treated with intravenous infusions of fluids, antibiotics, oxygen therapy, and analgesic drugs.
If the crisis still does not respond, an exchange blood transfusion may be performed.
This may be done regularly for people who suffer frequent severe crises.... sickle cell anaemia
Various disorders can disrupt the water balance in the body, leading to accumulation of water in the tissues. Examples include kidney failure, liver cirrhosis, severe heart failure, diseases of the adrenal glands, and certain lung or ovarian tumours producing a substance similar to ADH (antidiuretic hormone). Water intoxication is also seen in association with the use of Ecstasy (MDMA), during which excessive amounts of water are drunk. There is also a risk of water intoxication after surgery, caused by increased ADH production.... water intoxication
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