Acute severe asthma
Acute severe asthma, also known as status asthmaticus, is an acute exacerbation of asthma that does not respond to standard treatments of bronchodilators (inhalers) and corticosteroids. Asthma is caused by multiple genes, some having protective effect, with each gene having its own tendency to be influenced by the environment although a genetic link leading to acute severe asthma is still unknown .Symptoms include chest tightness, rapidly progressive dyspnea(shortness of breath), dry cough, use of accessory respiratory muscles, fast and/or labored breathing, and extreme wheezing. It is a life-threatening episode of airway obstruction and is considered a medical emergency. Complications include cardiac and/or respiratory arrest. The increasing prevalence of atopy and asthma remains unexplained but may be due to infection with respiratory viruses.
Signs and symptoms
An exacerbation (attack) of asthma is experienced as a worsening of asthma symptoms with breathlessness and cough (often worse at night). In acute severe asthma, breathlessness may be so severe that it is impossible to speak more than a few words (inability to complete sentences).
On examination, the respiratory rate may be elevated (more than 25 breaths per minute), and the heart rate may be rapid (110 beats per minute or faster). Reduced oxygen saturation levels (but above 92%) are often encountered. Examination of the lungs with a stethoscope may reveal reduced air entry and/or widespread wheeze. The peak expiratory flow can be measured at the bedside; in acute severe asthma the flow is less than 50% a person's normal or predicted flow.
Very severe acute asthma (termed "near-fatal" as there is an immediate risk to life) is characterised by a peak flow of less than 33% predicted, oxygen saturations below 92% or cyanosis (blue discoloration, usually of the lips), absence of audible breath sounds over the chest ("silent chest"), reduced respiratory effort and visible exhaustion or drowsiness. Irregularities in the heart beat and abnormal lowering of the blood pressure may be observed. Severe asthma attack can cause symptoms such as:
- Shortness of breath
- Can't speak in full sentences
- Feel breathless even when lying down
- Chest feels tight
- Bluish tint to the lips
- Feeling agitated, confused, and unable to concentrate
- Hunched shoulders, and strained muscles in stomach and neck
- Feeling the need to sit or stand up to breathe more easily
The cause for Acute Severe Asthma attacks is still unknown and experts are also unsure of why its developed and why it doesn't respond to typical asthma treatments,although there are some speculations:
Not seeing a doctor regularly, therefore asthma is not under good control
- Coming in contact with asthma triggers
- Allergies or severe allergic reactions
Not using the peak flow meter and not taking asthma medication as directed by a primary care physician (PCP) correctly
Not following an asthma action plan correctly
- respiratory infections
- severe stress
- cold weather
- air pollution
- exposure to chemicals and other irritants
Severe Acute Asthma can be diagnosed by a primary care physician (PCP). A PCP will ask questions in regards to symptoms and breathing; they will also ask if fatigue or wheezing has been experience when breathing in or out; and also test using a peak expiratory flow and an oxygen saturation.
Status asthmaticus can be misdiagnosed when wheezing occurs from an acute cause other than asthma. Some of these alternative causes of wheezing are discussed below.
Clinical Immunology and Allergy