Asthma is a chronic inflammatory lung disease, characterised by recurrent breathing problems. It is a significant health problem, which has increased in incidence worldwide over the past decade. It is estimated that at least 7% of the population in the USA suffers from asthma, with prevalence higher in children than adults. In the UK, approximately 8% of the population has symptomatic asthma of which 12-15% are children. If not properly controlled, asthma causes significant morbidity and mortality.Asthma cannot be cured; however treatment is aimed at reducing the frequency, severity and length of attacks. Treatment plans would vary from individual to individual since a lot of different factors are involved in asthma.

Asthma

More than 5.2 million people (of which 1.1 million are children) are being treated for asthma in the UK. It affects one in 12 adults and one in 8 children in the UK, and is a controllable but incurable disease, which causes about 180,000 deaths a year.

What is asthma?

Asthma is a chronic inflammatory lung disease, which is characterised by recurrent breathing problems. It is a significant health problem, which has increased in incidence worldwide over the past decade. It is estimated that at least 7% of the population in the USA suffers from asthma, with prevalence higher in children than adults. In the UK, approximately 8% of the population has symptomatic asthma of which 12-15% are children. If not properly controlled, asthma causes significant morbidity and mortality.

Types of asthma

Asthma is divided into a number of different types including,

1. Allergic asthma, which 90% of asthma sufferers have. It is triggered by allergens including pet dander, pollen, and dust mites. Other triggers can include pollutants, smoke, irritants, viral infections, and wood dust. Individuals suffering specific allergen-induced asthma are usually aware of the allergen causing their asthma and as a result try to avoid it. More often than not, childhood asthma is considered an allergic type.

2. Intrinsic Asthma, in which allergies do not play a part. It is not likely to develop in children and typical onset occurs after age 40. Intrinsic asthma may be caused by respiratory irritants such as perfumes, cleaning agents, smoke and cold air. Others include gastroesophageal reflux (GERD) and upper respiratory infections.

3. Nocturnal asthma, which affects people when asleep, regardless of what time of day they are sleeping. Symptoms tend to be at their worst between midnight and 4a.m. It can be triggered by allergens in bedding or the bedroom. Other triggers include a decrease in room temperature. It is thought that about 75% of asthmatics are affected by nocturnal asthma.

4. Exercise-induced asthma, which is attributed to the loss of heat and moisture in the lungs, occurring as a result of strenuous exercise. This can affect individuals who already have some form of allergy or who have a family history of allergies. The only known symptom for exercise-induced asthma is frequent coughing during exercise.

5. Occupational asthma, which occurs as a direct result of breathing chemical fumes, wood dust, or other irritants over a long period of time, usually at work. It is thought that about 15% of asthmatics have occupational asthma.

6. Steroid-resistant asthma, caused by the overuse of asthma medications, which can lead to status asthmaticus, a severe asthma attack which does not respond to medication and may require mechanical ventilation to reverse it. This form of asthma can be prevented by strictly following directions for proper use of prescribed medications.

Triggers

The exact cause of asthma is not fully understood; however it can be triggered by a number of factors. These include,

1. Exposure to allergens such as house dust mite droppings, pollen, mould, cockroach, animals' dander, tobacco smoke, wood smoke.

2. Exposure to strong odours such as perfumes, household cleaning agents, cooking fumes, and gases.

3. Changing weather conditions including thunder storms.

4. Infections especially respiratory tract infections caused by viruses, including common cold, viral or sinus infections.

5. Exercise, which is one of the more common precipitants of airway obstruction in asthmatic patients.

6. Certain medications, particularly nonsteroidal anti-inflammatory drugs (NSAIDs).

7. Psychosocial/emotional factors such as stress. These have long been known to worsen asthma symptoms, although the mechanisms behind these effects remain unknown.

Risk factors

Certain risk factors make it more likely that a person will have asthma. These include,

1. Family history: if one or both parents have asthma, you are more likely to develop the condition. The likelihood is greater if a mother has asthma than if the father does.

2. Children who have allergies are more likely to have asthma than those who do not have allergies

3. Gender: In children, boys are more likely than girls to have asthma. This reverses with age as more adult women than men develop asthma.

4. Cigarette smoking: Inhalation of cigarette smoke during pregnancy has been linked with abnormal lung functions, airway hyper-reactivity and allergy in newborn.

5. Atopy, which is a greater than usual immune response to foreign substances.

6. An infant feeding method other than breastfeeding.

7. Low birth weight

8. Sinusitis

9. Obesity

10. Medical conditions such as acid reflux or gastroesophageal reflux disease (GERD), congestive heart failure, respiratory infections in childhood, pulmonary embolism

11. Outdoor pollution

Symptoms

Asthma symptoms may differ in adults and children, and the severity and duration of symptoms vary from mild to severe.

Common asthma symptoms include:

1. Wheezing

2. Tightness in the chest

3. Difficulty breathing

4. Shortness of breath

5. Cough

6. Chest pain

There are usually warning signs that signal an impending asthma attack. By learning to recognize these early symptoms as warning signs, you can help prevent attacks or reduce their severity.

In Children:

1. A whistling or wheezing sound when exhaling

2. Frequent coughing or cough spasms

3. Waking up coughing in the night

4. Shortness of breath while stationery or exercising

5. Feelings of tightness in the chest

6. Restless sleep patterns

7. Sweating

8. Anxiety

In Adults:

1. Increased shortness of breath and wheezing

2. Chest tightness or pain

3. Sweating

4. Anxiety

5. An increased need to use bronchodilators

What Happens During an Asthma Attack?

Exposure to asthma triggers can cause airways to contract and become inflamed, narrowed, and clogged with mucus. Less room is available for air to flow in and out of the lungs. The duration of the asthma attack varies. Attacks range from mild to severe and last anywhere from a few minutes to several days. During attacks, bronchial muscles go into spasm, causing air to be trapped in tiny air breathing sacs in the lungs, called alveoli. Asthma attacks may be fatal if not identified and treated.

Treatment

Asthma cannot be cured; however treatment is aimed at reducing the frequency, severity and length of attacks. Treatment plans would vary from individual to individual since a lot of different factors are involved in asthma. A large number of patients are treated with inhalers, which could be reliever inhalers or preventer inhalers.

1. Reliever inhalers

These are prescribed to help treat symptoms when they occur, that is, during an asthma attack, when peak flow readings are low and before exercise or activity. They help relax and open the airways, making it easier to breath and reducing the risk of an attack. Relievers are medically known as bronchodilators as they widen the bronchi or airways.

Some relievers alleviate symptoms almost instantly (rescue relievers). Others have a longer lasting action (long-lasting relievers). Long-lasting relievers may be prescribed if wheezing, breathing difficulties and coughing persist despite using a preventer and a rescue reliever, or if the sufferer has nocturnal asthma. Common rescue relievers are salbutamol and terbutaline. Another type of reliever is ipratropium bromide, which is often prescribed for babies under two and for older people. Long-lasting relievers include oxitropium, salmeterol, and eformoterol, all of which are inhaled. Side effects are usually mild and pass away quickly. The main ones are a slightly increased heartbeat, and muscle trembling, especially in the hands.

Occasional use of a reliever inhaler may be all that is required where symptoms occur every now and again; however, where a reliever inhaler is required at least 3 times a week to ease symptoms, a preventer inhaler is usually advised.

2. Preventer inhalers

These are prescribed to help prevent asthma symptoms. These are typically used everyday, even when patients do not have symptoms. Preventers are designed to quell swelling and inflammation in the airways and reduce mucus; as such, the sensitivity of the airways is reduced, thereby minimising potential damage. Most preventers are based on corticosteroids, which are steroids but completely different from the anabolic steroids sometimes used by bodybuilders and athletes. The most common types of preventer inhalers include beclomethasone, budesonide, and fluticasone. There are also non-steroid preventers, which are usually used for children; these include sodium cromoglycate and nedocromil sodium. These are usually taken three to four times a day and are not generally as effective as steroids.

It usually takes about 7-14 days for the steroid in a preventer inhaler to build up its effect. As such, it will not give any immediate relief of symptoms. However, after a week or so of treatment, the symptoms will often disappear, or are much reduced. It can take up to six weeks for maximum benefit, after which patients should not need to use a reliever inhaler very often, if at all.

Side-effects of preventer inhalers are unusual at normal doses. These may include hoarseness or loss of voice, oral yeast infections (thrush), and cough. Long-term use may slightly increase the risk of skin thinning, bruising, osteoporosis, eye pressure and cataracts. In children, inhaled corticosteroids may slow growth.

Types of inhaler devices

There are different types of inhaler devices to suit different people. These include,

1. Pressured Metered Dose Inhalers (MDI's), also known as "puffers". They are used to deliver the exact amount of sprayed aerosolised medicine. Medication is mixed into a liquid and forced under pressure into a small aerosol canister. Once activated (usually by pushing down the canister) the liquid evaporates, leaving the active ingredient that is inhaled. A measured dose of the drug is released every time the canister is pushed down. Both relievers and preventers can be given via a puffer.

2. Dry powder inhalers, which contain a small amount of drug in a powder form, contained in a capsule. When activated, the capsule breaks and the powder can be inhaled. Various devices are made by different companies and each has a different method of providing the correct amount of powder for each dose. This type of inhaler device is not usually suitable for children under six. This is because it is usually necessary to breathe fairly hard so as to get the powder into the lungs, children younger than six years cannot often breathe in hard enough to suck in all the powder required.

3. Spacers, which help to coordinate breathing with an inhaler. A spacer is typically a long tube, which clips onto an inhaler, with a mouthpiece on the other end of the tube to breathe in and out of. Spacers allow more medication to enter the lungs than would be possible using an inhaler alone.

4. Nebulisers, in which air or oxygen is forced through the liquid form of a drug, creating a mist, which is inhaled through a mask or mouth piece. They are used to administer high doses of relievers (more than conventional inhalers) in emergency cases and sometimes in children who are too young to use inhalers.

Other medications for the treatment of asthma include, leukotriene modifiers, which reduce the production of, or block the action of leukotrienes (substances released by cells in the lungs during an asthma attack). Leukotrienes cause the lining of the airways to become inflamed, leading to wheezing, shortness of breath and mucus production. Leukotriene modifiers are used alongside other medications to help prevent asthma attack. They are not as effective as inhaled corticosteroids but are ideal for patients who suffer from mild asthma or those who want to avoid corticosteroids.

Theophylline is another form of treatment, which can have anti-inflammatory effects. It is a bronchodilator and may be helpful in relieving symptoms of nocturnal asthma. Due to its low cost, it can be used as an add-on therapy when further asthma control is required. It can however produce some dose-related side effects, including nausea and vomiting, acid reflux, fast or irregular heartbeat, and severe abdominal pain, and as such patients taking theophylline must get regular blood tests to make sure they are getting the correct dosage.

Cromolyn and nedocromil are medications, which can be used daily to help prevent attacks of mild to moderate asthma, as they are rapidly absorbed from the lungs and are impressively safe. They are however not effective for everyone.

Oral and intravenous corticosteroids such as prednisolone and methylprednisolone can be taken to treat acute to severe asthma attacks. These may take a few hours or days to be fully effective. Just like their inhaler counterparts, long-term use of these medications can cause serious adverse effects.

Preventative measures

A number of preventative measures can be taken to prevent asthma attacks. Identifying and avoiding indoor and outdoor allergens and irritants is the best way to do this; however this is easier said than done since there are a wide variety of outdoor allergens and irritants, as well as indoor allergens such as dust mites, cockroaches, and mould, which can trigger attacks. Preventatives measures which could be taken include, but are not limited to the following,

1. Keep indoor humidity low (less than 50%), since dust mites and mold increase in high humidity. This can be done by using dehumidifiers.

2. Get rid of dust collectors, including heavy drapes, carpeting, & stuffed animals.

3. Keep the house dry and well ventilated.

4. Replace carpeting with hard flooring, if possible.

5. Wash all bedding and stuffed animals in hot water every 7-14 days.

6. Use an airtight, allergy-proof plastic cover on all mattresses and pillows.

7. Avoid exposure to molds by keeping away from damp basements, water-damaged areas of the house, wet leaves or garden debris.

8. Cover air vents with filters.

9. For seasonal problems, keep windows closed in the car and home to avoid exposure to pollens and use air conditioning instead. Stay indoors during the midday and afternoon when pollen counts are at their highest.

10. Avoid being outside on days when pollution or ozone counts are high.

11. Avoid known triggers, such as chemicals, pets, and cigarette smoke.

12. Avoid smoky environments.

13. Where cockroaches are a problem, they should be controlled with insect sprays and roach traps, as cockroach allergens are a very common asthma and allergy trigger.

14. Provide good ventilation with HEPA (high-efficiency particulate air) filters, air purifiers or air sterilisers, and air conditioners.

15. Regularly vacuum the house including all soft furnishings, with a HEPA vacuum, central vacuum system or a very good steam cleaner as steam cleaning removes allergens and kills dust mites. When you are likely to be exposed to substances that give you a reaction, particularly when cleaning the house, you should wear a mask.

16. Regularly use prescribed preventers and always have inhalers close at hand.

17. Take relievers before exercise if necessary.

18. Closely follow any action plan created with the help of your doctor.

19. Monitor your breathing and learn to recognize warning signs of an impending attack such as slight coughing, wheezing or shortness of breath.

20. Regularly measure your peak airflow with a home peak flow meter to ascertain your lung function every now and again.