Asthma - symptoms, diagnosis, treatment

sthma is a chronic (long-term) disease that causes airways in the lungs to become irritated and inflamed (swollen) making it hard to breathe. Symptoms include coughing, wheezing and shortness of breath.

Background

Asthma, sometimes referred to as bronchial asthma, can start at any age but commonly begins in childhood. Many children grow out of asthma by their teens. Others first develop asthma in adulthood (adult-onset asthma). Asthma often runs in families and can be associated with allergic conditions such
as eczema and hay fever .

Signs and symptoms

With asthma the airways in the lungs are sensitive to certain irritants. When exposed to these irritants the small airways in the lungs (the bronchioles) become irritated and swollen and the muscles surrounding the bronchiole walls constrict (bronchoconstriction). Excess mucous is produced inside the airways and it becomes difficult for air to travel to and from the lungs, making breathing difficult and producing the cough, wheeze and shortness of breath that are characteristic of asthma. 

Asthma attacks are characterised by difficulty breathing – especially exhaling. The severity of asthma symptoms varies between individuals. Some experience only mild symptoms while others have very severe symptoms. Attacks can happen suddenly and can occur after periods of being relatively symptom free. A severe asthma attack can be life threatening if treatment is not sought immediately.  Common signs and symptoms of asthma include: 

• Coughing – which may worsen at night
• Wheezing
• Chest tightness
• Shortness of breath
• Difficulty speaking (in more severe attacks)
• Blueness around the mouth (in more severe attacks).

Causes

The exact cause of asthma is not fully understood. It is believe to be caused by a combination of genetic (inherited) and environmental factors.  It may be related to modern living, including environmental changes, diet or exposure to some infections.

It is known that most people with asthma constantly have some degree of inflammation in their airways. Their airways are also sensitive to certain irritants, known as triggers. Triggers can cause tightening or constriction of the already inflamed airways, thus provoking an asthma attack. Each individual tends to have different asthma triggers. Common asthma triggers include: 

• Pollens or moulds
• House dust mites
• Animals
• Air pollution
• Certain foods or food additives
• Strong perfumes
• Exercise
• Cigarette smoke
• Some medicines eg: aspirin, non-steroidal anti-inflammatory drugs, beta blockers
• Respiratory infections such as colds and influenza
• Changes in temperature and humidity
• Psychological influences eg: extremes of emotion
• Workplace irritants eg: paint and varnish fumes, flour, wood dust. 

Diagnosis

If asthma is suspected, the following may be undertaken by a doctor to assist with diagnosis: 

• A full medical history including any family history of asthma
• Discussion of current symptoms
• Physical assessment 
• A chest x-ray may be ordered
• Measurement of how quickly air can be exhaled using a peak flow meter. 

Asthma symptoms and signs vary through the day and through the week.  Peak flow meter tests twice daily for a week or before and after using a reliever inhaler will show this variation.  The peak flow rate may vary by more than 20% in asthma sufferers.

Sometimes specialised challenge tests may be useful.  These tests use a chemical to try to provoke a brief episode of asthma which can be measured.  This can confirm a diagnosis and indicate severity.

Collection of phlegm or measurement of nitric oxide may be used to follow the progress of more complex asthma.

Specialist referral should be considered if there is uncertainty about the diagnosis, when the response to initial treatment is not what was expected, or when an occupational cause of asthma is possible. 

Treatment

While asthma cannot be cured, it can be controlled by avoiding triggers and through the use of medications. There are a variety of asthma medications available.  A doctor will be able to discuss which may be most appropriate for the patient.  The main types of medications used to control asthma are:

Preventers:These are usually an inhaled corticosteroid medication which has the effect of reducing swelling and decreasing the body’s reaction to triggers . It takes time for preventers to start acting (up to three months of regular use).  They are taken on a regular basis each day to prevent symptoms.  Examples of preventers are fluticasone (Flixotide), budesonide (Pulmicort) and beclomethasone (Beclozone).

Relievers:These inhaled medications cause the airways’ muscle to relax thus reducing constriction and relieving the symptoms of asthma. They are often referred to as bronchodilators. The are quick acting and are used to relieve symptoms once they have started.  Examples of short-acting relievers are terbutaline (Bricanyl) and salbutamol (Ventolin).

Symptom controllers:These are long-acting inhaled relievers and are used in conjunction with a preventer. They work by keeping the airway muscles relaxed and are usually used twice a day. The use of a symptom controller should reduce the need to use a short acting reliever. Examples of symptom controllers are formoterol (e.g. Foradil) and salmeterol (e.g. Serevent).

Combination inhalers:Combination inhalers contain both preventer and symptom controller medicine in one device. Examples of combination inhalers are fluticasone and salmeterol (Seretide) and budesonide and formoterol (Symbicort).

Because the medications mentioned above are inhaled, they are delivered straight to the lungs and can start their action immediately.  Increased frequency and/or severity of asthma symptoms may require a change in the treatment regimen or an increase in the amount of medication taken. A course of corticosteroid medication (e.g. prednisone) in either liquid or tablet form, may be prescribed until symptoms are controlled.

Severe asthma attacks may require hospitalisation to control symptoms. Relieving medication may need to be given using a nebuliser (inhaled in a fine mist of oxygen via a specialised mask or mouthpiece) or intravenously (as an infusion into a drip in the hand or arm). Intravenous corticosteroids may also be given. 

Management of asthma

Learning to avoid triggers can help reduce symptoms and the frequency of asthma attacks.  Be aware of symptoms and take appropriate medication to ease these. This may involve increasing asthma medication.  Regular use of a peak flow meter and recording of those measurements can indicate how well controlled asthma is and indicate worsening of the condition.

Having a self management or action plan is also an important tool in the management of asthma. This is a written guideline of what to do when asthma worsens.  It is usually individually formulated in conjunction with a doctor or asthma nurse specialist.

Getting a seasonal influenza vaccination ("flu jab") will reduce the risk of influenza, which in turn will reduce the risk of serious asthma.  People who are on regular preventive therapy for asthma (as well as people with various other medical conditions) can see their doctor about a free influenza vaccination each autumn.

Other control methods include breathing techniques such as the Buteyko Method. Staying physically fit and avoiding smoking can also minimise asthma symptoms and attacks.  Desensitisation and allergen avoidance may also be useful.  Alternative therapies such as acupuncture, homeopathy and massage prove effective for some people in managing their asthma.

Be alert for signs of worsening asthma: night waking, breathlessness or difficulty speaking on exertion, loss of response to your reliever. 

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