Asthma

Asthma is a disease of the human respiratory system in which the airways narrow, often in response to a "trigger" such as exposure to an allergen, cold air, exercise, or emotional stress. This narrowing causes symptoms such as wheezing, shortness of breath, chest tightness, and coughing, which are the hallmarks of asthma. Between episodes, most patients feel fine.

Diagnosis

Diagnosing asthma

In most cases, a physician can diagnose asthma on the basis of typical findings in a patient's clinical history and examination. Asthma is strongly suspected if a patient suffers from eczema or other allergic conditions?suggesting a general atopic constitution?or has a family history of asthma. While measurement of airway function is possible for adults, most new cases are diagnosed in children who are unable to perform such tests. Diagnosis in children is based on a careful compilation and analysis of the patient's medical history and subsequent improvement with an inhaled bronchodilator medication. In adults, diagnosis can be made with a peak flow meter (which tests airway restriction), looking at both the diurnal variation and any reversibility following inhaled bronchodilator medication.

Related Topics:
Diagnose - Eczema - Allergic - Atopic constitution - Family history - Medical history - Bronchodilator - Peak flow meter - Diurnal - Variation - Medication

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Testing peak flow at rest (or baseline) and after exercise can be helpful, especially in young asthmatics who may experience only exercise-induced asthma. If the diagnosis is in doubt, or if chronic obstructive pulmonary disease is suspected, a more formal lung function testing may be conducted. Once a diagnosis of asthma is made, a patient can use peak flow meter testing to monitor the severity of the disease.

Related Topics:
Chronic obstructive pulmonary disease - Lung function testing

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Differential diagnosis

Before diagnosing someone as asthmatic, alternative possibilities should be considered. A physician taking a history should check whether the patient is using any known bronchoconstrictors (substances that cause narrowing of the airways, e.g., certain anti-inflammatory agents or beta-blockers).

Related Topics:
Alternative possibilities - Anti-inflammatory - Beta-blockers

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Only a minority of asthma sufferers have any identifiable allergy trigger. The majority of these triggers can often be identified from the history; for instance, asthmatics with hay fever or pollen allergy will have seasonal symptoms, those with allergies to pets may experience an abatement of symptoms when away from home, and those with occupational asthma may improve during leave from work. Occasionally, allergy tests are warranted and, if positive, may help in identifying avoidable symptom triggers.

Related Topics:
Allergy - Hay fever - Pollen - Allergy tests

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After pulmonary function has been measured, radiological tests, such as a chest X-ray or CT scan, may be required to exclude the possibility of other lung diseases. In some people, asthma may by triggered by gastroesophageal reflux disease, which can be treated with suitable antacids. Very occasionally, specialized tests after inhalation of methacholine?or even less commonly histamine?may be performed.

Related Topics:
Chest X-ray - CT scan - Antacid - Methacholine - Histamine

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