What is Asthma?
Asthma is a long term inflammatory disease of the airways due to bronchial hyper responsiveness to a variety of agents, leading to airway constriction and causes cough, shortness of breath, wheeze and chest tightness usually at night or early in the morning, which are reversible either spontaneously or with treatment. Airway hyper-responsiveness is due to an exaggerated response to numerous stimuli or agents.
How common is Asthma?
Asthma is a common disease, affecting approximately 130 million people world wide. It is slightly more in boys more commonly than girls and, after puberty, women slightly more commonly than men. Each year, approximately 470,000 hospital admissions and 5000 deaths in the United States are attributed to asthma.
How does Asthma develop?
It develops due to a complex interaction between genetic factors 9which are passed down to offspring) and environmental factors. Airway inflammation occurs when a susceptible individual is exposed to certain environmental factors. When exposed to a trigger agent, the muscles of the bronchus are triggered and suddenly shorten or close up.
Subsequently, there is a swelling of the mucosa or the covering of the airway caused by cells of the immune system. Small finger like projections in the airway sweeping foreign substances in the airway called Cilia, are damaged. Thus, there is a release of mucus in the airway. Continual exposure to triggers worsens the airway and causes long-term changes in it, a process termed “airway remodeling”. This causes increased airway wall thickness, increased mucus glands and production of mucus as well as increased vascularity.
What are the risk factors and triggers?
The strongest identifiable predisposing factor for the development of asthma is atopy – a genetic tendency to develop allergic diseases such as asthma, allergic rhinitis and atopic dermatitis due to a heightened immune response to allergens.
Exposure of sensitive patients to inhaled allergens increases airway inflammation, airway hyper responsiveness, and symptoms. Symptoms may develop immediately (immediate asthmatic response) or 4–6 hours after allergen exposure (late asthmatic response).
Common aeroallergens include house dust mites (often found in pillows, mattresses, upholstered furniture, carpets, and drapes), cockroaches, cats, and seasonal pollens. Substantially reducing exposure reduces pathologic findings and clinical symptoms.
Many asthma genes or gene complexes have been identified. Now, it is being taught that up to 60% of all asthma cases are hereditary. This means that asthmatics can transfer the disease to their offspring.
- Gender: Male gender is a risk factor for asthma in children. In children <14 years, asthma is twice as prevalent in boys as in girls. Female gender is a risk factor for asthma in adulthood. The reason is unknown but it may be due to women’s smaller lung size
- Environmental risk factors: Outdoor and indoor allergens like pollen, dust, chemicals like paint, perfume, formalin etc. can cause a person to have an asthmatic attack. Exposure to environmental tobacco smoke increases asthma symptoms and the need for medications and reduces lung function. Some individuals may experience asthma symptoms after exposure to aspirin, nonsteroidal anti-inflammatory drugs, or Tartrazine dyes.
- Emotional stress
- Cold air
- Viral disease
- Pollution: exhaust fumes, tobacco smoke, dust, vapour.
- Drugs, food additives and food preservatives (Aspirin and NSAIDS, Beta blockers)
- Perimenstrual (catamenial asthma)
- Gastro esophageal reflux disease
What are the different types of Asthma?
Intrinsic Asthma - Here, there is no definite causal agent. No allergic or (personal family) history is identified. It is usually adult onset, often follows severe respiratory illness and is more refractory to treatment.
Extrinsic Asthma – This is caused by a definite external cause. Here, there is a strong family history of allergies, usually begins at a young age. There are other allergic manifestations in patients like atopic dermatitis. Often, there are known specific trigger agents (e.g. pollen, animal dander).
What are the signs and symptoms?
The frequency of asthma symptoms is highly variable. Some patients may have only a chronic dry cough and others a productive cough. Some patients have infrequent, brief attacks of asthma and others may suffer nearly continuous symptoms. Asthma symptoms may occur spontaneously or may be precipitated or exacerbated by many different triggers as discussed above.
- Intermittent difficulty in breathing,
- Nasal mucosal swelling,
- increased nasal secretions, and nasal polyps are often seen in patients with allergic asthma.
- Eczema, atopic dermatitis, or other manifestations of allergic skin disorders may also be present.
- Hunched shoulders and use of accessory muscles of respiration suggest an increased work of breathing.
- Increased respiratory rate,
- audible wheeze,
- hyperinflated chest,
- hyper-resonant percussion note,
- diminished air entry,
- widespread polyphonic wheeze.
In severe cases, inability to complete sentences, increased pulse rate. A silent chest, cyanosis, bradycardia, exhaustion, confusion, feeble respiratory effort are features of life threatening asthma.
How can you make a diagnosis of Asthma?
A number of other diseases can mimic asthma. Thus, only a healthcare professional can make a diagnosis of asthma, typically after taking a history, doing a physical examination and carrying out one or more of the tests below.
- Lung Function Test
- Full blood count
- Chest X ray
- Sputum test.
What medications should I take?
If you have symptoms similar to the aforementioned symptoms or you are an already diagnosed asthmatic, you should go to the nearest hospital for consultation as asthma medications are varied and mostly streamlined according to your level of control.
Asthma medications can be divided into two categories:.
- Agents that offer quick relief of symptoms, and
- Agents taken to promote long-term asthma control.
Quick-relief medications are taken to promote prompt reversal of acute airflow obstruction and relieve accompanying symptoms by direct relaxation of bronchial smooth muscle.
Long-term control medications are taken daily independent of symptoms to achieve and maintain control of persistent asthma.
Many asthma medications are administered orally or by inhalation. Inhalation of an appropriate agent results in a more rapid onset of pulmonary effects as well as fewer systemic effects compared with oral administration of the same dose.
In a given individual, the intensity of asthma treatment is adjusted, for the most part, to achieve four goals:
1. To allow the patient to pursue the activities of his or her daily life without excessive interference from asthma;
2. To allow the patient to sleep without awakening because of asthmatic symptoms;
3. To minimize the use of rescue bronchodilator treatments; and
4. To prevent the need for unscheduled medical care.