What is Asthma
Essentially asthma is a chronic and recurring inflammation of the air ways (bronchi) that results in obstruction of air flow. Asthma is largely controllable and to an extent curable, depending on the stage and extent of the disease.
Asthma has no single cause. It is caused my multiple factors, which can be divided in two groups:
Asthma is caused and maintained by more than one of the following causes:
• Genetic or hereditary cause
• Environmental factors (pollution, pollen, etc) - Systemic diseases
• Mental stress
Asthma has a tendency to recur and get chronic. It is often observed to be a life long disease like diabetes or high blood pressure.
One or more of the above factors lead to altered immunity which eventually leads to chronic asthma. It may be noted that the genetic tendency for asthma forms soil, leading to susceptibility to be affected by other external or internal trigger factors.
Allergens Causing Asthma:
• Air pollutants
• Smoking and second hand smoking
• Respiratory infections
• Common cold, Sinusitis
• Exercise, physical exertion
• Cold air
• Medications: Aspirin, NSAID, Beta blockers etc.
• GERD (Gastro esophageal Reflux Disease)
The list can be exhaustive though each person may have a different individual or a combination of triggering factors.
Asthma Risk Factors:
The following factors increase your chances of developing Asthma.
• Urban / Industrial areas where the exposure to environmental pollutants is more.
• Work Environment - Exposure to chemicals, dust, industrial waste.
• Heredity - Have a history of either parents or family members suffering from Asthma.
• Childhood - History of recurrent respiratory tract infections, low birth weight.
What happens in Asthma? (Pathogenesis):
• There is a decrease in the lumen of the air ways resulting from a twofold response to the allergens and other irritants.
• Primarily in a hyper reactive response, the smooth muscles in the airways constrict and narrow excessively.
• Followed by an inflammatory response where the immune system responds to the allergens by sending white blood cells and other immune factors to the airways.
• These inflammatory factors cause a swelling of the airways and also an increase in the mucus secretion thus causing symptoms like wheezing, cough and shortness of breath.
The most common symptoms are:
• Difficulty in breathing
• Mucus production
The most important and distressing symptom is the breathlessness or sense of suffocation, which may be of varying intensity. Some patients may not have cough or mucus production (expectoration) at all.
The most common symptoms are:
• Periodical (once in a a week to once in a year)
• Seasonal (a few weeks in a year)
• Continuous (all throughout or most of the time)
The symptoms might get triggered by one or more of the following:
• Physical exertion
• Change in weather or temperature
• Mental stress
• Exposure to pollution (dust, chemical, pollen, etc.)
• Without any apparent reason
Asthma Symptoms & Severity Levels of Asthma:
The intensity, duration and recurrence of the symptoms vary from person to person. Even in the same person the symptoms may vary from episode to episode. Some people with asthma may have extended symptom-free periods, interrupted by periodic asthma episodes, while others may have some symptoms every day. Very often some people with asthma have symptoms only during exercise, or when they are exposed to allergens or viral respiratory tract infections.
Common Symptoms of Asthma:
• Cough is most often worse at night.
• Wheezing. It is a whistling sound when you breathe.
• Shortness of breath. A feeling of breathlessness.
• Nasal flaring
• Rapid pulse
• In severe cases bluish discoloration of lips/face
• Retractions of intercostals spaces
Based on symptoms, asthma is divided into four levels of severity are:
• Mild intermittent: you have episodes of asthma symptoms twice a week or less, between episodes, however, you have no symptoms and your lung function is normal.
• Mild persistent asthma: you have asthma symptoms more than twice a week, but no more than once in a single day. You are bothered by symptoms at night more than twice a month.
• Moderate persistent asthma: you have asthma symptoms every day, and you are bothered by nighttime symptoms more than once a week.
• Severe persistent asthma: you have symptoms throughout the day on most days, and you are bothered by nighttime symptoms often.
Pulmonary function test:
• Challenge test
• Exhaled Nitric oxide test
• Complete Blood count
• Chest and Sinus X-rays
• CT scan (not done routinely)
• GERD assessment test (if associated gastric symptoms)
Asthma Diagnosis: Clinical Tests for Asthma
Diagnosis of asthma is mostly clinical. Some investigations to assess the extent of asthma and association of other conditions is usually called for in most cases. A detailed medical history and physical examination is done to assess the presence or severity of the following symptoms.
• Recurrent respiratory infections
• Allergic cough worse at night
• Sudden onset of wheezing and shortness of breath when exposed to allergens
• Your family history of asthma and allergies
• Medicines you may have used to help your breathing
A physical examination of your respiratory system and a general examination is done to rule out other illness.
After medical history and examination, pulmonary function test and other investigations may be included to complete the diagnosis