Cause Asthma runs in families, so that parents with asthma have a strong risk of having children with asthma, or with other atopic (see ATOPY) illnesses such as HAY FEVER or eczema (see DERMATITIS). There is therefore a great deal of interest in the genetic basis of the condition. Several GENES seem to be associated with the condition of atopy, in which subjects have a predisposition to form ANTIBODIES of the IgE class against allergens (see ALLERGEN) they encounter – especially inhaled allergens.
The allergic response in the lining of the airway leads to an in?ammatory reaction. Many cells are involved in this in?ammatory process, including lymphocytes, eosinophils, neutrophils and mast cells. The cells are attracted and controlled by a complex system of in?ammatory mediators. The in?amed airway-wall produced in this process is then sensitive to further allergic stimuli or to non-speci?c challenges such as dust, smoke or drying from the increased respiration during exercise. Recognition of this in?ammation has concentrated attention on anti-in?ammatory aspects of treatment.
Continued in?ammation with poor control of asthma can result in permanent damage to the airway-wall such that reversibility is reduced and airway-narrowing becomes permanent. Appropriate anti-in?ammatory therapy may help to prevent this damage.
Many allergens can be important triggers of asthma. House-dust mite, grass pollen and animal dander are the commonest problems. Occupational factors such as grain dusts, hard-metals fumes and chemicals in the plastic and paint industry are important in some adults. Viral infections are another common trigger, especially in young children.
The prevalence of asthma appears to be on the increase in most countries. Several factors have been linked to this increase; most important may be the vulnerability of the immature immune system (see IMMUNITY) in infants. High exposure to allergens such as house-dust mite early in life may prime the immune system, while reduced exposure to common viral infections may delay the maturation of the immune system. In addition, maternal smoking in pregnancy and infancy increases the risk.
Clinical course The major symptoms of asthma are breathlessness and cough. Occasionally cough may be the only symptom, especially in children, where night-time cough may be mistaken for recurrent infection and treated inappropriately with antibiotics.
The onset of asthma is usually in childhood, but it may begin at any age. In childhood, boys are affected more often than girls but by adulthood the sex incidence is equal. Children who have mild asthma are more likely to grow out of the condition as they go through their teenaged years, although symptoms may recur later.
The degree of airway-narrowing, and its change with time and treatment, can be monitored by measuring the peak expiratory ?ow with a simple monitor at home – a peak-?ow meter. The typical pattern shows the peak ?ow to be lowest in the early morning and this ‘morning dipping’ is often associated with disturbance of sleep.
Acute exacerbations of asthma may be provoked by infections or allergic stimuli. If they do not respond quickly and fully to medication, expert help should be sought urgently since oxygen and higher doses of drugs will be necessary to control the attack. In a severe attack the breathing rate and the pulse rate rise and the chest sounds wheezy. The peak-?ow rate of air into the lungs falls. Patients may be unable to talk in full sentences without catching their breath, and the reduced oxygen in the blood in very severe attacks may produce the blue colour of CYANOSIS in the lips and tongue. Such acute attacks can be very frightening for the patient and family.
Some cases of chronic asthma are included in the internationally agreed description CHRONIC OBSTRUCTIVE PULMONARY DISEASE (COPD) – a chronic, slowly progressive disorder characterised by obstruction of the air?ow persisting over several months.
Treatment The ?rst important consideration in the treatment of asthma is avoidance of precipitating factors. When this is a speci?c animal or occupational exposure, this may be possible; it is however more di?cult for house-dust mite or pollens. Exercise-induced asthma should be treated adequately rather than avoiding exercise.
Desensitisation injections using small quantities of speci?c allergens are used widely in some countries, but rarely in the UK as they are considered to have limited value since most asthma is precipitated by many stimuli and controlled adequately with simple treatment.
There are two groups of main drugs for the treatment of asthma. The ?rst are the bronchodilators which relax the smooth muscle in the wall of the airways, increase their diameter and relieve breathlessness. The most useful agents are the beta adrenergic agonists (see ADRENERGIC RECEPTORS) such as salbutamol and terbutaline. They are best given by inhalation into the airways since this reduces the general side-effects from oral use. These drugs are usually given to reverse airway-narrowing or to prevent its onset on exercise. However, longer-acting inhaled beta agonists such as salmeterol and formoterol or the theophyllines given in tablet form can be used regularly as prevention. The beta agonists can cause TREMOR and PALPITATION in some patients.
The second group of drugs are the antiin?ammatory agents that act to reduce in?ammation of the airway. The main agents in this group are the CORTICOSTEROIDS. They must be taken regularly, even when symptoms are absent. Given by inhalation they have few side-effects. In acute attacks, short courses of oral steroids are used; in very severe disease regular oral steroids may be needed. Other drugs have a role in suppressing in?ammation: sodium cromoglycate has been available for some years and is generally less e?ective than inhaled steroids. Newer agents directed at speci?c steps in the in?ammatory pathway, such as leukotriene receptor-antagonists, are alternative agents.
Treatment guidelines have been produced by various national and international bodies, such as the British Thoracic Society. Most have set out treatment in steps according to severity, with objectives for asthma control based on symptoms and peak ?ow. Patients should have a management plan that sets out their regular treatment and their appropriate response to changes in their condition.
Advice and support for research into asthma is provided by the National Asthma Campaign.
Prognosis Asthma is diagnosed in 15–20 per cent of all pre-school children in the developed world. Yet by the age of 15 it is estimated that fewer than 5 per cent still have symptoms. A study in 2003 reported on a follow-up of persons born in 1972–3 who developed asthma and still had problems at the age of nine. By the time these persons were aged 26, 27 per cent were still having problems; around half of that number had never been free from the illness and the other half had apparently lost it for a few years but it had returned.... asthma
See HEART, DISEASES OF.... cardiac cycle
Although there are numerous possible sources of electrical interference with pacemakers, the overall risks are slight. Potential sources include anti-theft devices, airport weapon detectors, surgical diathermy, ultrasound, and short-wave heat treatment. Nevertheless, many pacemaker patients lead active and ful?lling lives.... cardiac pacemaker
Habitat: Throughout the warmer parts of India.Ayurvedic: Granthiparni, Kaaka- puchha.Folk: Gathivan, Deepamaal (Maharashtra).
Action: Leaves—spasmolytic. Ash of flower head—applied to burns and scalds, in ringworm and other skin diseases.The Ayurvedic Pharmacopoeia ofIn- dia recommends the root in cough, bronchitis and dyspnoea.The root contains n-octacosanol, n-octacosanoic acid, quercetin, 4,6,7- trimethoxy-5-methylchromene-2-one, campesterol and beta-sitosterol-beta- D-glucopyranoside.The plant contains 4,6,7-trimethoxy- 5-methyl-chromene-2-one.The leaves contain neptaefolin, nep- taefuran, neptaefuranol, neptaefolinol, leonitin, neptaefolinin and (-)-55, 6- octadecadienoic acid.The seed oil contains oleic, linoleic, palmitic and stearic acids. The fattyFamily: Labiatae; Lamiaceae.
Habitat: Native to Europe; also distributed in Himalayas from Kashmir to Kumaon.English: Common Motherwort, Lion's Tail.Unani: Baranjaasif. (Also equated with Artemesia vulgaris Linn; and Achillea millifolium Linn.)
Action: Stomachic, laxative, antispasmodic, diaphoretic, em- menagogue (used in absent or painful menstruation, premenstrual tension, menopausal flushes). Hypnotic, sedative. Used as a cardiac tonic. (Studies in China have shown that Motherwort extracts show antiplatelet aggregation actions and decrease the levels of blood lipids.)Key application: In nervous cardiac disorders and as adjuvant for thyroid hyperfunction. (German Commission E.) As antispasmodic. (The British Herbal Pharmacopoeia.) The British Herbal Compendium indicated its use for patients who have neuropathic cardiac disorders and cardiac complaints of nervous origin.The plant contains diterpene bitter principles, iridoid monoterpenes, flavonoids including rutin and querci- trin, leonurin, betaine, caffeic acid derivatives, tannins and traces of a volatile oil.The herb is a slow acting adjuvant in functional and neurogenic heart diseases. Its sedative and spasmolytic properties combine well with Valeriana officinalis or other cardioactive substances.The herb contains several components with sedative effects—alpha- pinene, benzaldehyde, caryophyllene, limonene and oleanolic acid. (Sharon M. Herr.)
Habitat: Western Europe. Seeds are imported into India from Persia.English: Pepper-Grass.Unani: Bazr-ul-khumkhum, Todari (white var.).
Action: Seeds—blood purifier; prescribed in bronchitis.The fatty acid of the oil are: oleic 12.9, linoleic 47.87, linolenic 5.43, erucic 31.97, stearic 0.54 and palmitic 1.22%.The seed mucilage on hydrolysis gave galactose, arabinose, rhamnose and galacturonic acid.Flowering tops and seeds contain a bitter principle, lepidin.The plant yield a sulphur-containing volatile oil.... leonurus cardiaca
Symptoms: worse after exercise, breathlessness, headache, general weakness, feeble pulse, pale face, skin cold, swollen tissues pit on pressure.
Treatment. Alternatives:– Teas. Black Cohosh, Broom tops, Buchu, Dandelion, Hawthorn, Parsley root. Tea. Formula. Equal parts: Broom tops, Motherwort, Yarrow. 2 teaspoons to each cup water brought to boil and simmered 5 minutes in covered vessel. 1 cup 3-4 times daily.
Tablets/capsules. Buchu, Dandelion, Hawthorn, Juniper, Motherwort.
Formula. Dandelion 2; Hawthorn 2; Stone root 1. Mix. Dose: Powders: 750mg (three 00 capsules or half a teaspoon). Liquid extracts: 1 teaspoon. Tinctures: 2 teaspoons. Thrice daily.
Practitioner. Lily of the Valley, BPC 1934: 5-20 drops, 2-3 times daily.
Squills, tincture: resembles Digitalis in action. Dose: 1-3 drops, as prescribed.
Tinctures. Dandelion 2; Lily of the Valley 2; Stone root 1; Cayenne (tincture) quarter. Mix. Dose: 1 to 2 teaspoons thrice daily.
Popular formula. Tincture Scilla 5.0; Tincture Crataegus 10.0; Tincture Valerian to make 30.0. 15 drops thrice daily. (German Extemporaneous Formulae)
Diet. High protein. See: DIET – HEART AND CIRCULATION. ... cardiac dropsy
Treatment. Agents in frequent use: Broom, Lily of the Valley, Hawthorn (blossoms or berries), Motherwort.
Tea. Combine equal parts: Dandelion root, Motherwort, Yarrow. 2 teaspoons to each cup boiling water; infuse 5-15 minutes; 1 cup thrice daily.
Powders. Equal parts: Dandelion root, Juniper berries, Hawthorn berries. Mix. Dose: 500mg (two 00 capsules or one-third teaspoon).
Practitioner. Lily of the Valley. Dose as BHP (1983): Liquid Extract: 1:1 in 25 per cent alcohol, 0.6-2ml. Tincture: 1:5 in 40 per cent alcohol, 0.5-1ml. Thrice daily.
Dropsy in children: cucumber juice extracted from vegetable with aid of a juicer. As many cupfuls as well-tolerated. If vomiting is induced, it should be regarded as favourable.
Diet. Lacto-vegetarian, salt-free, bottled or spring water, honey. ... dropsy: cardiac
In sinus tachycardia, the rate is raised, the rhythm is regular, and the beat originates in the sinoatrial node (see pacemaker). Supraventricular tachycardia is faster and the rhythm is regular. It may be caused by an abnormal electrical pathway that allows an impulse to
circulate continuously in the heart and take over from the sinoatrial node. Rapid, irregular beats that originate in the ventricles are called ventricular tachycardia. In atrial flutter, the atria (see atrium) beat regularly and very rapidly, but not every impulse reaches the ventricles, which beat at a slower rate. Uncoordinated, fast beating of the atria is called atrial fibrillation and produces totally irregular ventricular beats. Ventricular fibrillation is a form of cardiac arrest in which the ventricles twitch very rapidly in a disorganized manner.
Sinus bradycardia is a slow, regular beat. In heart block, the conduction of electrical impulses through the heart muscle is partially or completely blocked, leading to a slow, irregular heartbeat. Periods of bradycardia may alternate with periods of tachycardia due to a fault in impulse generation (see sick sinus syndrome).
A common cause of arrhythmia is coronary artery disease, particularly after myocardial infarction. Some tachycardias are due to a congenital defect in the heart’s conducting system. Caffeine can cause tachycardia in some people. Amitriptyline and some other antidepressant drugs can cause serious arrhythmias if they are taken in high doses.
An arrhythmia may be felt as palpitations, but in some cases arrhythmias can cause fainting, dizziness, chest pain, and breathlessness, which may be the 1st symptoms.
Arrhythmias are diagnosed by an ECG. If they are intermittent, a continuous recording may need to be made using an ambulatory ECG.
Treatments for arrhythmias include antiarrhythmic drugs, which prevent or slow tachycardias.
With an arrhythmia that has developed suddenly, it may be possible to restore normal heart rhythm by using electric shock to the heart (see defibrillation).
Abnormal conduction pathways in the heart can be treated using radio frequency ablation during cardiac catheterization (see catheterization, cardiac).
In some cases, a pacemaker can be fitted to restore normal heartbeat by overriding the heart’s abnormal rhythm.... arrhythmia, cardiac