Asthma

ASTHMA

DEFINITION

Asthma is a common chronic inflammatory disease of the airways characterized by variable and recurring symptoms, airflow obstruction, and bronchospasm.
Although asthma is a chronic obstructive condition, it is not considered as a part of chronic obstructive pulmonary disease as this term refers specifically to combinations of bronchiectasis,chronic bronchitis, and emphysema. Unlike these diseases, the airway obstruction in asthma is usually reversible; however, if left untreated, asthma can result in chronic inflammation of the lungs and irreversible obstruction.



SIGN AND SYMPTOMS

Common symptoms of asthma include wheezing, shortness of breath, chest tightness and coughing. Symptoms are often worse at night or in the early morning, or in response to exercise or cold air.

ASTHMA ATTACK

Severity of acute asthma exacerbations[19]

Near-fatal asthma High PaCO2 and/or requiring mechanical ventilation

Life threatening asthma Any one of the following in a person with severe asthma:-
Clinical signs Measurements
Altered conscious level
Peak flow < 33%

Exhaustion Oxygen saturation < 92%

Arrhythmia
PaO2 < 8 kPa

Low blood pressure
"Normal" PaCO2
Cyanosis

Silent chest
Poor respiratory effort
Acute severe asthma Any one of:-
Peak flow 33-50%
Respiratory rate ≥ 25 breaths per minute
Heart rate ≥ 110 beats per minute
Unable to complete sentences in one breath
Moderate asthma exacerbation Worsening symptoms
Peak flow > 50% best or predicted
No features of acute severe asthma


An acute exacerbation of asthma is commonly referred to as an asthma attack. The cardinal symptoms of an attack are shortness of breath (dyspnea), wheezing, and chest tightness.   Although the former is often regarded as the primary symptom of asthma. some people present primarily with coughing, and in the late stages of an attack, air motion may be so impaired that no wheezing is heard.[19]When present the cough...