Bronchial asthma

Diagnosis

Doctors usually diagnose asthma by looking for the most common symptoms: episodes of breathing troubles including dyspnoea, cough, and shortness of breath. When symptoms are not sufficient to formulate a diagnosis of asthma, doctors can use an instrumental test called spirometry, which measures airflow in the lungs. By comparing air flows under normal conditions, air flows during an asthmatic attack and air flows after the application of anti-asthma medication, your doctor is able to determine whether medication improves the patient’s breathing problems or not. If medication helps, doctor can diagnose asthma.

Identifying the specific trigger of asthma in the patient is often harder than the initial diagnosis. Some triggers can be easily recognizable and be more evident, for example, a patient can develop an asthma attack when using a particular cosmetic or household cleaning product. Other triggers are more difficult to identify, in which case doctors perform a series of allergy tests on the skin to help determine which triggers are causing the allergy. Skin tests are not conclusive, however, because patients may have skin reactions to substances that do not necessarily trigger an asthma attack. Doctors can use spirometry to assess airflow in a patient before and after exposure to common triggers. Triggers that reduce airflow can be responsible for asthma.

Epidemiology and aetiology

Around 4-5% or adults and up to 10% of children are estimated to suffer with asthma. The typical alteration is represented by an abnormal reactivity of the airways to specific and nonspecific stimuli. The main factor causing an asthmatic reaction is a nonspecific hyperreactivity of the tracheobronchial tree. The aetiology of airway hyperreactivity in asthma is uncertain, but inflammation has been proven to play a fundamental role. Airway reactivity can vary, and these variations are linked to different clinical symptoms. Several factors may increase the reactivity: allergies, medications, environmental or work-related factors, infections, physical or emotional stress. The most common factors include: airborne allergens, acetylsalicylic acid, B-blockers, sulfites found in foods, environmental pollution, and respiratory infections. Asthma attacks are caused by airway hyperreactivity, i.e. an excessive reaction of the bronchi and bronchioles to environmental and physiological triggers. The most common causes of asthma attacks are extremely small and light airborne particles that are inhaled into the lungs. When they enter the airway, these particles, known as environmental factors, trigger an inflammatory response in the airway walls, causing the so-called asthma attack.

For some people, allergens are the environmental cause of asthma. Allergens are generally natural occurring substances, such as pollen, dust mites, mould spores, pet dander or particles of dust mites and cockroach waste. Allergen cause an excessive response of the immune system, where specific antibodies called immunoglobulin E start the inflammatory response.

Asthma also occurs in people who do not suffer with allergies. In these cases, chemical irritants may cause an inflammatory response, which is triggered in a different way from how it would with allergens.

Not all triggers are environmental. Some triggers can come from inside the body and are known as physiological triggers; these include exercise and infections such as the common cold. Food and drinks can also sometime caus asthma attacks. Chemicals found in food or medications, for example food sulfites found in beer and wine, or medications such as aspirin and ibuprofen, can be particularly problematic for many people suffering with asthma. Intense emotions, such as crying, screaming or laughing, can cause hyperventilation, a rapid inhalation of oxygen that causes bronchoconstriction of the airways. In asthmatic subjects, hyperventilation often turns into an attack. Many asthmatic subjects are particularly sensitive to exercise during the cold months.

Research suggests that genetic factors may increase the risk of developing this condition. Children with a family history of asthma are more prone to developing the disease compared to other children. Despite this apparent genetic connection, many people may still develop this condition even with no family history of asthma.