By Massoud Mahmoudi
Approximately 20 million Americans suffer from asthma. Asthma is a disease of all ages - 9 million children under age 18 have it - and it causes 5 million deaths a year, resulting in a total annual cost in health care and lost productivity of $16.1 billion.
Asthma is a chronic, inflammatory disease of the airways. Asthmatic lungs respond to various stimuli such as allergens, smoke, cold weather, pollution, exercise and aspirin. If untreated, asthma can change the structure of the airways and cause them to lose normal anatomy and function.
This week, I’ll look at the different types of asthma, what the symptoms of the disease are and the different ways it can be diagnosed. Next time, I’ll explore treatments and offer tips to prevent asthma attacks.
There are several types of asthma: allergic asthma, occupational asthma, exercise-induced asthma, aspirin-induced asthma, adult-onset asthma and cough-variant asthma.
Allergic asthma: This is the most common type of asthma. In the United States, 10 million people suffer from it, and it generally starts in childhood. The asthma symptoms are caused by an underlying sensitivity to allergens.
Occupational asthma: Symptoms occur at work. Patients develop symptoms because of exposure to chemicals, vapors, aeroallergens and irritants. When off work, especially on weekends or days off, patients feel better, but when they return to work the symptoms recur.
Exercise-induced asthma: Exercise, often heavy exercise such as running, induces symptoms. Patients do not usually experience symptoms with light exercise or when at rest.
Aspirin-induced asthma: Ingestion of aspirin or products in the aspirin family prompt symptoms. I have a patient who has aspirin sensitivity; once, after ingesting an aspirin, she developed severe shortness of breath and had to be taken to the emergency room.
Adult-onset asthma: This type of asthma is not as common as allergic asthma. Some patients experience their asthma symptoms after a bout of bronchitis or pneumonia. The affected individuals have no history of childhood asthma.
Cough-variant asthma: The only symptom of this type of asthma is a cough. Usually there is no shortness of breath or wheezing involved. The affected individuals mostly cough at night.
General asthma symptoms include shortness of breath, chest tightness, wheezing or cough. The affected individuals may be awakened from sleep by chest tightness or shortness of breath. Frequency and length of symptoms are indicators of asthma severity.
Diagnosis of asthma is based on history of illness, physical examination and diagnostic testing.
Your physician may suspect asthma because of medical history alone. For example, if pollens or pet danders bring asthmatic symptoms, you may have allergic asthma. If taking aspirin causes shortness of breath, you may have aspirin-induced asthma.
During an asthma flare-up, asthmatics may make audible wheezing sounds. The physician can use a stethoscope to listen to the lungs and hear wheezing or ventilation of air coming into and going out of the airways. Asthmatics may also have tightness in the chest. If the asthma is controlled, a regular physical examination may not show any signs of lung abnormality.
Sometimes doctors will order chest X-rays for asthma sufferers. The X-ray is not a diagnostic tool, but it may give information on the condition of the lungs. In cases of severe asthma, the lungs appear hyper-inflated, meaning increased air in the lungs has caused inflation. Asthmatics have obstruction of larger airways and cannot exhale normally. Chest X-rays can also pinpoint other lung abnormalities, such as pneumonia or bronchitis, that may have contributed to the asthma flare-up.
Diabetics need to monitor blood sugar with a device known as a glucometer. Patients with high blood pressure need to monitor blood pressure using a sphygmomanometer. Asthmatics need to measure their airway condition with a peak flow meter, a small hand-held device that has a mouthpiece and a graded hollow tube with a knob. The patient should take a deep breath, place the mouth on the mouthpiece and blow hard and fast. As the patient blows into the device, the knob moves and you can read the number along the tube where the knob has stopped. This number is a peak of expiratory flow. In asthmatics, this number is low because there is an obstruction of the airways and not much air can come out with the exhalation.
To know if the measurement is reasonable, it should be compared with a chart of measurements of normal lungs for various ages.
Spirometry is a machine that measures your lung function and diagnoses airway obstruction or asthma. Your allergist measures your lung function initially and periodically thereafter. The spirometry measurements guide your allergist in assessing your respiratory condition and making recommendations on your medication regiments.
Dr. Massoud Mahmoudi is an assistant clinical professor in the division of allergy and immunology at UC San Francisco’s Department of Medicine and is in private practice, with offices in Los Altos and Los Gatos. E-mail him questions at doctormahmoudi@yahoo.com.
