Chronic Asthma

Topic Highlights

●    Asthma is a chronic inflammatory disease of the airways due to increased sensitivity to foreign particles.

●    Inflammation leads to narrowing of the airways, resulting in wheezing and breathlessness.

●    Asthma can be reversed and responds well to various medications.

●    This visual presentation describes various types of asthma, asthma symptoms, treatment ' including use of inhalers, and self help.

Transcript

Asthma is one of the most common diseases in the world. It currently affects around 300 million adults and children. Experts predict that by 2025 this figure may rise to 400 million. This mirrors an increase in other atopic conditions such as eczema, hay fever and rhinitis. In Europe, the rate is highest in the UK, where over 15% of the population is asthmatic. Albania, Greece, Switzerland and Denmark have the lowest prevalence.

Asthma is a disease of the respiratory system. This system is responsible for supplying oxygen to the body and removing carbon dioxide. It is made up of the nose, throat (or pharynx), windpipe (or trachea) and the two lungs situated on either side of the chest. Each lung consists of two branches called bronchi, which divide into smaller and smaller branches called bronchioles and end as air sacs called alveoli.

When we breathe in, air passes into the lungs, ultimately reaching the alveoli. Here, the blood absorbs oxygen from the inhaled air and releases carbon dioxide back into the alveoli to be breathed out. If inhaled foreign particles reach the lungs, the body sends immune cells to attack them, and produces mucus in the local area to protect the walls of the airways.

The airways of asthmatic individuals are chronically inflamed, which means they are typically irritated and swollen. They are also extra sensitive or hyper-responsive, so they react more easily and strongly to inhaled foreign particles. During an asthma attack, the airways become very narrow, the muscles around the airways tighten and too much mucus is produced, obstructing air movement. Because it is harder for air to pass through the narrow airways, symptoms of shortness of breath, wheezing, coughing and tightness in the chest develop. Itching on the chest or neck may be an early symptom, especially in children.

An attack may be over in minutes, or it may last for hours or days. Most sufferers are symptom-free in the periods between attacks. However, in some people, the airways may be constantly impaired, and they may cough and wheeze most of the time. There are several forms of asthma and the features vary greatly from patient to patient.

The allergic (or extrinsic) type accounts for 90% of cases and typically develops in childhood. Most sufferers will also have allergies or atopic conditions such as eczema, hay fever or rhinitis. Allergic asthma is triggered by inhaled allergens such as pet dander and dust mites, pollen and molds as well as foods including seafood and peanuts.

Non-allergic (or intrinsic) asthma is less common and normally starts in those over 40. It is not triggered by allergens but may develop after a respiratory viral infection (such as a cold, bronchitis and sinusitis), as a result of reflux disease, or may be triggered by exercise, stress or certain medications. Irritants in the general environment (such as cigarette smoke and air pollution), or at the person's workplace can worsen asthma symptoms.

The disease is only considered occupational if it develops specifically due to long-term exposure to irritants at the workplace. Culprits may include chemicals, metals, wood dusts and plant products. Some people suffer asthma attacks only when they exercise. This form can affect anyone regardless of age. Frequent coughing may be the only symptom. Aspirin and other non-steroidal anti-inflammatory drugs are known to worsen symptoms in asthmatics, especially women. The severity of asthma symptoms can also be influenced by pregnancy and obesity.

Triggers of non-allergic asthma can also worsen symptoms of the allergic type. Asthma can start at any age but is most common in children. Children often grow out of asthma by adulthood, and tend to suffer from the allergic form. They are prone to attacks following viral infections in the respiratory system.

Asthma is classified depending on how severe and frequent the attacks are, and by the results of peak flow tests. The categories are mild intermittent, mild persistent and moderate or severe persisting. Diagnosis is usually made by assessing the symptoms ' cough, shortness of breath, chest tightness and, the characteristic feature, wheeze. Symptoms are typically worse at night, intermittent, variable and provoked by triggers.

Peak flow testing is invaluable for diagnosis. It can also be used to assess disease severity, identify exercise- and occupational-related forms and measure response to treatment. Peak flow assesses airway obstruction by measuring how fast you can breathe air out of your lungs. The flow rate will be lower than expected if you have asthma and will vary day-to-day. There will also be a marked dip in airflow in the mornings.

Histamine challenge tests can also be used diagnostically to identify bronchial hyper-responsiveness. Further tests of lung function can help rule out other diseases and skin prick tests may be useful to identify triggering allergens. In young children, lung tests may be difficult to perform, so diagnosis may be based on symptoms, risk factor assessment and response to treatment.

Management of asthma follows a stepped approach and uses two types of treatment: those that relieve symptoms during an attack and those that control asthma over the long term. Patients are allocated a step according to their disease severity. In the first step, inhaled short-acting inhaled beta-2-agonists are used to relieve symptoms. Examples include salbutamol and terbutaline. The patient takes the medication only when an attack occurs. The drugs quickly expand or dilate the airways. The effect is short-lasting and wears off after an attack. Symptom relief may be the only intervention required in mild intermittent asthma. If symptom relief alone is not sufficient, disease-controlling drugs may also be prescribed. These drugs correct the underlying airway problems in asthma and therefore help to prevent attacks. The first controller drug to be used is usually an inhaled steroid such as fluticasone or budesonide. Steroids reduce the inflammation in the airways, decrease swelling and mucus secretion and therefore improve breathing.

The next step, if required, is to add an inhaled long-acting beta-2-agonist (such as eformoterol and salmeterol). These drugs keep the airways dilated over a long period. Other preventative options that can be added to the mix are leukotriene-modifying agents (which reduce inflammation and dilate the airways), the dilating agent theophylline or beta-2-agonist tablets. Alternatively, a higher dose of inhaled steroid dose may be tried. The last step is to begin continuous or frequent courses of oral steroids to target the inflammation. Treatment is stepped down or decreased as symptoms improve.

A completely different approach to therapy targets antibodies that are produced by the immune system following exposure to an allergen. Monoclonal antibodies, such as omalizumab, block the action of antibodies and thereby reduce the severity of the asthma attack. This treatment may be most suitable for patients with severe persistent allergic asthma.

Several different inhaler devices are available to deliver asthma medication to the lungs. The type of device may depend on the prescribed medication. A metered-dose inhaler or MDI delivers a measured amount of medicine directly into the lungs in the form of a spray. A spacer may be attached to aid inhalation. To administer the medication, shake the inhaler. Remove the cap from the mouthpiece and attach the spacer device if required. Holding your head erect, exhale normally. Close your mouth around the open end of the spacer or hold the mouthpiece a couple of inches in front of your mouth if a spacer is not used. Breathe slowly and press the inhaler once. Continue to inhale for several seconds. Hold your breath to a count of ten or for as long as possible. Remove the device from your mouth. Exhale slowly. Rinse your mouth with water to reduce the likelihood of unwanted effects. An autohaler is a breath-activated MDI. It is used by pressing a switch and then breathing through the mouthpiece. It is not recommended for young children.

A dry powder inhaler is similar to a MDI, but is breath activated. The dry powder medication comes as a capsule or disk or may be stored in a compartment in the inhaler. Different types of dry powder inhalers or DPIs are available depending on the medication prescribed. Examples include Accuhaler, Aerolizer, Rotahaler and Turbohaler. Accuhalers contain several doses of the medication in powder form. To use this device, push the thumb grip away until a click is heard. Slide the lever away until it clicks. Seal the mouthpiece with the lips. Breathe in steadily and deeply. Remove the Accuhaler and hold your breath as long as possible. Exhale slowly. Push the thumb grip towards you and close the device.

An Aerolizer uses medication in capsule form. To use, pull the cap. Twist the mouthpiece to expose the capsule chamber. Take one blistered capsule and place it in the chamber in the base. Now close the mouthpiece by twisting. Holding the Aerolizer erect, press the two buttons on the base once. A click indicates that the capsule is pierced. Release the buttons and close the mouthpiece with your lips ensuring that the two buttons are on the sides. Inhale deeply. The capsule spins in the chamber and disperses the medicine.

A Rotahaler uses a capsule called a Rotocap. Hold the Rotahaler erect and insert the Rotocap into the opening with the transparent end first. The top of the capsule should be level with the opening. Twist the base of the Rotahaler to split the capsule. Inhale deeply and breathe out slowly. A rattling sound is heard as the capsule moves. Open the inhaler to remove the used capsule. The Rotahaler is generally used to deliver salbutamol.

A Turbohaler is a multi-dose inhaler. It has an indicator, which shows the number of doses left. In some Turbohalers a red indicator appears when there are twenty doses left. Holding the Turbohaler upright, remove the cap and twist the colored grip as far as possible and then bring it back. A click is heard when it is ready. Inhale deeply. Remove the inhaler and then exhale. Replace the cap after use.

Nebulisers are used to administer high doses of medication directly into the lungs since regular inhalers may be insufficient. The nebuliser converts the asthma drug from a solution into a fine spray from the mouthpiece or facemask to be inhaled. The medication can be inhaled by regular breathing over 5 to 10 minutes

It is important to learn about your disease and its treatment including how to use and look after your inhaler. Visit your doctor regularly to review your care plan. You should also learn how to recognize lack of asthma control from symptoms or peak flow measurements, and to know when to seek emergency care. Identifying and avoiding the factors that trigger your attacks is key. For example, exposure to house dust mites can be minimized by using protective mattress covers, removing or heavily vacuuming carpets and applying anti-mite chemicals to soft furnishings, particularly where you sleep.

Similarly, preventing further exposure to the sensitizing substance is critical in occupational asthma. All patients should avoid smoking and second-hand smoking. Parents of asthmatic children should stop smoking. If you are obese, it helps if you can lose some weight. Although you cannot cure asthma, you can control it by following these simple measures as well as taking your prescribed medications.