Asthma is a chronic condition of the lungs that has two main components. Two things happen inside the lungs of women suffering with Asthma�constriction, the tightening of the muscles surrounding the airways, and inflammation, the swelling and irritation of the airways. Constriction and inflammation cause narrowing of the airways, by a combination of muscle spasm, mucosal swelling and bronchial secretion with symptoms such as wheezing, coughing, chest tightness, or shortness of breath. Furthermore, there is increasing evidence that, if left untreated, asthma can cause long-term loss of lung function. 

CLINICAL FEATURES :
Asthma might be either episodic or chronic . In general atopic individuals tend to develop episodic asthma and non-atopic individuals develop chronic asthma.

[ Types of Asthma ]

Episodic asthma: In this type of disease the patient has no respiratory symptoms between episodes of asthma . Episodes of asthma might be triggered by allergens, exercise and viral infections such as common cold or may be apparently spontaneous . Attacks may be mild to to severe and may last for hours ,days or even weeks . For example, some people find that their asthma is worse in the spring when there is an increase in flowering plants. Others find their asthma is worse in the late summer or early fall when ragweed and leaves from trees are more likely to cause problems. Exercise induced asthma,  simply refers to the fact that some asthmatics have primarily their asthma symptoms during exercise, and sometimes have no other asthmatic symptoms. It refers to the fact that in these individuals, when they exercise, most commonly in cold weather, they will begin to wheeze, become short of breath, and when tested will have all the characteristics of asthma, but often only during those circumstances. During the rest of their lives, they may have no other asthmatic symptoms.  Exercise, cold air, sudden changes in air temperature, and even gastroesophageal reflux (heartburn) may be triggers for people with non-allergic asthma. 

Severe acute asthma: This is a term used in place of "status asthmaticus" which is a description for life threatening attacks of asthma .The patient usually adopts an upright position fixing the shoulder girdle to assist the accessory muscles of respiration . Their is often an incidence of an unproductive cough which aggravates respiratory distress . The respiratory symptoms are accompanied by tachycardia, pulsus paradoxus, sweating and in severe cases central cyanosis. 

Chronic asthma: with symptoms of chest tightness ,wheeze and breathlessness on exertion ,together with spontaneous cough and wheeze during the night ,may be chronic unless controlled by appropriate therapy .Episodes of 'severe acute asthma' can occur ,and cough production of mucoid sputum with recurrent episodes of frank respiratory infection  is common in this type of asthma which in adult may be difficult to distinguish from chronic bronchitis .

CAUSES OF ASTHMA:
Asthma triggers are irritants in the environment that can provoke asthma symptoms or attacks. There are many triggers that can aggravate asthma symptoms, and they often differ from person to person. You can help prevent bothersome asthma symptoms by identifying and avoiding your known triggers. In fact, identifying and avoiding triggers should be part of a detailed plan of action to successfully help manage your asthma.

It may not be possible to completely eliminate asthma triggers. You should still try to remove as many as possible from your home and work surroundings. This can help you enjoy a healthier life with fewer asthma symptoms and attacks. 

• Smoking
  Do not allow tobacco smoke in the home or around you, especially in the bedroom or a car. Do avoid smoke-filled areas. 

• Dust Mites
  Dust mites are tiny bugs you cannot see that live in cloth and carpet. 
  Encase your mattress and pillow in a special dust-proof cover. 
  Replace old pillows with new ones at least once every 5 years. 
  Wash the sheets and blankets on the bed each week in hot water. Water must be hotter than 130� F (this kills dust mites). 
  During the day, keep dust off your bed by covering the entire bed with a bedspread. At night, take off the bedspread and put it in another room. 
  If you�ve done all these things and still have trouble with your asthma, talk to your healthcare professional. 

• Pets
  Some people are allergic to the flakes of skin (dander) or dried saliva that come from animals with fur or feathers. 
  Find a new home for the pet or keep pets out of your home. This can be very hard to do but might be the best way to control your asthma if you are allergic to animals. 
  If you cannot keep pets out of your home, keep the pet out of your bedroom and keep the bedroom door closed. 
  Consider placing filters on the air vents in your bedroom. 
  Remove carpets and furniture covered with cloth from your home. If this is not possible, keep the pet out of the rooms where these are located. 

• Cockroaches
  Many people with asthma are allergic to the dried droppings and remains of cockroaches. 
  Keep all food out of your bedroom. 
  Keep food and garbage in closed containers (never leave food out). 
  Use baits or traps to eliminate cockroaches. 
  If a spray is used to kill roaches, stay out of the room until the odor goes away. 

• Indoor Mold
  Fix leaky faucets, pipes, or other sources of water. 
  Clean mold off of surfaces with a cleaner that has bleach in it. 
  Replace or wash moldy shower curtains. 

• Smoke, Strong odors, and Sprays
  If possible, do not use a wood-burning stove, kerosene heater, or fireplace. 
  Try to stay away from strong odors and sprays, such as perfume, talcum powder, hair spray, and paints. 

• Pollen or Outdoor Mold
  During your allergy season, you should: 
  Try to keep your windows closed. 
  Stay indoors with the windows closed during the midday and afternoon, if you can. Pollen and some mold spore counts are highest at that time. 
  Ask your healthcare professional whether you need to adjust your current asthma treatment regimen before your allergy season starts. 

• Activity
  If you have asthma, you can still be active. See your healthcare professional if you have asthma symptoms when you are active�like when you exercise, do sports, play, or work hard. 
  Ask your healthcare professional about taking medicine for your asthma before you exercise to prevent symptoms. 
  Warm up for about 6 to 10 minutes before you exercise by stretching or walking. 
  Try not to work or play hard outside when the air pollution or pollen levels (if you are allergic to pollen) are high. 

• Colds and Infections
  If colds and infections trigger your asthma, talk with your healthcare professional about developing a treatment plan to follow when you start feeling sick. Also consider: 
  Getting a flu shot 
  Trying to stay healthy by getting plenty of rest, eating a balanced diet, exercising regularly, drinking plenty of fluids, and avoiding contact with others who have colds or the flu. 

• Weather
  Cover your nose and mouth with a scarf on cold or windy days. 
  Avoid going outside on days when pollen or mold counts are high if you are allergic to pollens or molds (check weather reports or the newspaper). 

• Genetics
  Polymorphisms of the beta2-adrenoceptor genes appear to have an association with adult-onset asthma in sedentary, but not in active women, according to researchers at the Harvard Medical School in Boston and at other centers.Dr. R Graham Barr and colleagues noted that a "sedentary lifestyle is associated with adult-onset asthma." Furthermore, Glu27 polymorphism of the beta2-adrenoceptor may predict body mass index (BMI). Gly16 polymorphism is also associated with asthma severity. To read more regarding the report at : 
  Genetically Influenced Asthma Onset Greater in Sedentary Women (Dec 13, 2001)

• Other Triggers
  Sulfites in foods: For example, do not drink beer or wine, and do not eat shrimp, dried fruit, or processed potatoes if they cause asthma symptoms. 
  Other medicines: Tell your healthcare professional about all the medicines you may take. Include aspirin, cold medicines, nonsteroidals (e.g., ibuprofen, naproxen), and even eye drops

SYMPTOMS OF ASTHMA
What happens to you when your asthma is not under control? A whistling sound that you make when you breathe? A tight grip around your chest? Most patients with asthma have one or more of these classic symptoms: 

1. Chest tightness: Feels like a rope being tightened around your chest. During an attack the chest is held near the position of full inspiration and the percussion note may be hyper resonant.

2. Shortness of breath: Feels like you're trying to breathe through a straw�or worse, like you can't catch your breath at all. Breathing out is especially tough. The airflow obstruction which characteristically fluctuates causes mismatch of alveolar ventilation and perfusion and increases the work of breathing .Being more marked during expiration it also causes air to be 'trapped' in the lungs causing shortness of breathing .

3. Coughing: A cough or hack that may not go away, and often occurs or is worse at night. 

Death may occur from alveolar hypoventilation and severe arterial hypoxaemia culminating in cardiac arrest . Here are the 2 main things that happen deep within the airways of your lungs when you have asthma symptoms that may lead to an attack: 

• Constriction: The muscles around the airways in the lungs squeeze together or tighten. This tightening is often called "bronchoconstriction," and it can make it hard for you to breathe the air in or out of your lungs. 

• Inflammation: The airways of the lung are often swollen and irritated if you have asthma, and become more swollen and irritated when an attack begins. Your healthcare professional may refer to this swelling and irritation as "inflammation." Inflammation can reduce the amount of air that you can take in or breathe out of your lungs. 

The bottom line on asthma is this: it can be a quiet, sneaky condition that's always with you. Your airways may be constricted and inflamed, whether you have symptoms or not. That's why it's so important to treat asthma every day�even when you're feeling fine�because there is increasing evidence that, if left untreated, asthma can cause a long-term loss of lung function. 

MANAGEMENT  & PREVENTION OF ASTHMA

1. Avoidance of Allergens: There are a few instances in which a single agent can be identified as the cause of attacks of asthma .These allergens include grass pollens, mites animal dander , drugs industrial chemicals such as isocyanates , and certain articles of diet . Prevent the exposure to these agents as far as possible .

2. Hyposensitisation:  This is the only specific measure available for the prevention of damaging antigen-antibody reaction . It involves the subcutaneous injection of initially very small ,but gradually increasing doses of extracts of allergens believed to be responsible for the patient's asthma .Hyposensitisation may be of some value when only a single allergen ,such as grass pollen ,house dust mite or animal dander is implicated but it is not without the risk of producing an acute anaphylactic reaction . Hyposensitisation with a mixture of allergens is irritable and cannot be recommended . 

3. Drugs which control or suppress clinical manifestation of asthma: 

• Sodium Cromoglycate: Administered by inhalation . This has actions which include prevention of mediator release  from the mast cells . It seems to be of particular value in children with atopic asthma  and should be given a trial of at least 4 weeks duration in all such patients .This drug has no place in the management of severe asthma .

• Nedocromil sodium: This an anti-inflammatory drug with similar properties to those of sodium cromoglycate and is administered by inhalation from a metered dose inhaler in a dose of 4mg,2-4 times daily .

• Ketotifen: Taken by mouth ,it is claimed to have a similar mode of action ,but is less effective than sodium cromoglycate or nedocromil sodium and has the serious disadvantage in some patients of causing drowsiness which may be of dangerous side effect in patients driving car or operating machinery .The recommended dose is 1-2 mg twice daily with food .  

4. Bronchodilators and Corticosteroids: Bronchdilators have a direct and immediate effect on airflow obstruction ,corticosteroids relieve and prevent airflow obstruction indirectly by their less rapid anti-inflammatory action .

        Beta-adrenoreceptor agonist stimulate adenyl cyclase the enzyme which catalyses the formation of cyclic adenosine 5'-phosphate (AMP) from adenosine triphosphate (ATP). The effect caused is the relaxation of bronchial muscles ,but does not last for long .Corticosteroids also do have a beneficial effect on bronchial inflammation and decreases bronchial hyper-responsiveness . 

  In case of selective beta-agonists such as salbutamol , terbutaline or fenoterol ,the inhalation of aerosol has clear advantage over oral administration because it reduces airflow obstruction more rapidly .Also because the effective dose is much lower it is less liable to produce side effects such as tremor and anxiety .  

  VENTOLIN is a fast-acting beta2-agonist that is used as a rescue medicine. It acts within minutes to help relieve bronchospasm and its symptoms for up to 6 hours. VENTOLIN is indicated for the prevention and relief of bronchospasm in patients 4 years of age and older with reversible obstructive airway disease and for the prevention of exercise-induced bronchospasm in patients 4 years of age and older.
See your healthcare professional to find out if VENTOLIN is right for you at. http://gsk.ibreathe.com/ventolin/

TREATMENT OF :

• EPISODIC ASTHMA: Mild and infrequent episodes of asthma can be controlled by inhalation of bronchodilator aerosol .When the episodes are more frequent treatment should be supplemented by regular prophylactic therapy with  a corticosteroid by inhalation .

• EXERCISE-INDUCED ASTHMA: This common phenomenon which occurs particularly in children and young adults can often be prevented by the inhalation of 2 metered dose salbutamol or terbutaline  a few minutes before exercise .In the long-run, exercise has been shown to be good for asthma, but nevertheless, in the short-run, the patients can have these severe attacks that are precipitated by exercise. Regular treatment with sodium cromoglycate or an inhaled corticosteroid may be necesarry if treatment with a beta-adreno-receptor agonist is not wholly effective .

• CHRONIC ASTHMA: Some form of suppressive treatment is necesarry in all patients with chronic asthma . Sodium cromoglycate is worth a trial in children ,but a better response has been observed with inhalation of corticosteroid aerosol . Doses might vary with the severity of the illness .Corticosteroid aerosols are free from systemic unwanted effects in conventional doses ,but can cause oropharyngeal candidiasis  and a husky voice in few patients .

New asthma treatment
Recent findings from two phase III clinical trials show that treatment with Anti-IgE resulted in fewer asthma attacks and a decrease in the use of steroid medications in children and adults ages 6-75. In most cases, those in the study were able to completely stop taking the medications that had been an essential part of their lives.

How Anti-IgE Works
"This is a completely new approach to therapy, one that may greatly improve the treatment outlook for people with allergic asthma," says Henry Milgrom, a pediatric asthma specialist at the National Jewish Medical and Research Center in Denver, Colorado. "It is unlike anything that has been used before." 

When the allergic asthmatic encounters irritants like animal dander, molds, and dust mites--called allergens--an immune system antibody known as immunoglobulin or IgE binds to certain cells, and this causes allergy symptoms. These cells (mast cells) are found in the lungs, skin, and mucous membranes. Then, inflammatory agents (like histamine) are released.

When mast cells come in contact with an allergen, allergic symptoms result--coughing, wheezing, nasal congestion, hives, and inflammation and swelling of the airways. Anti-IgE works by binding to circulating IgE in the blood. It prevents IgE from binding to mast cells and later blocks the release of inflammatory agents.

Another benefit of Anti-IgE treatment is that it does not produce the serious long-term side effects that other asthma drug treatments cause. "Oral corticosteroids suppress the swelling and inflammation of the airways that are responsible for asthma symptoms," Dr. Milgrom says. "These drugs have side effects such as osteoporosis, high blood pressure, cataracts and, in children, slowed growth. The ability to eliminate or reduce the need for this medicine would be a very favorable development in the treatment of allergic asthma.".

References :

• Davidson's Principles and Practice of Medicine (sixteenth edition)

• http://gsk.ibreathe.com/ventolin/

• WF Health & Fitness Resources.

• http://www.acaai.org