ASTHMA

Asthma: Causes, Symptoms, and Treatments

what is Asthma?

Asthma is a chronic lung condition characterized by inflammation  that leads to wheezing, shortness of breath, chest tightness, and coughing. People with asthma have sensitive airways in their lungs which react to triggers, causing a ‘flare-up’. In a flare-up, the muscles around the airway squeeze tight, the airways swell and become narrow and there is more mucus. These things make it harder to breathe. Read more

Causes of Asthma

The causes of asthma are not fully understood, the main factors being environmental and genetic (family history) factors. In some people, family history plays a role. In some sensitive individuals, exposure to triggers or allergens (that is a substance which is capable of causing allergy) can set off asthma symptoms.
Research has shown that exposure to tobacco smoke (especially as a baby or young child), obesity and some occupational chemicals can increase the risk of developing asthma. Read more about triggers. Researches are still on-going and news drugs are emerging to deal with asthma

Symptoms of Asthma: Could it be asthma?

Symptoms vary at times and from person to person  - sometimes asthmatic patient may have no symptoms, especially when the asthma is well-controlled. Symptoms often most commonly encountered include:

• breathlessness  or dyspnea
• wheezing  
• chest tightness(tight feeling in the chest)
• continuing cough

Symptoms may occur at night, early in the morning or during/just after activity. They are caused by the narrowing of the airways.

If your asthma is well controlled, you should only have occasional asthma symptoms.

If you’re not sure if you have asthma you should see your doctor

Pathophysiology of Asthma- Changes that occur especially in the lungs when you have Asthma

An asthma attack is preceded by some changes in the lung tissues  - the muscles around the airways and the lining of the air passages tighten and become narrower. Swelling of the airway due to inflammation reduces the amount of air that can pass through the airways and leads to a high-pitched, wheezing sound resulting in forced breathing.

Asthma attacks can become life-threatening if the airflow in the lungs becomes severely blocked that Oxygen is lacking and the patient may be in need of therapeutic oxygen.

Diagnosis of Asthma

Your doctor will ask you certain questions pertaining to your medical and family history of asthma and allergies, a physical exam, and test results. The doctor will use a stethoscope to listen to your lungs sound, take your respiratory rate and observe any signs of asthma such as wheezing, swollen nasal passages, and runny nose.

Asthma tests may include a lung function test called spirometry that measures how much and how fast you can blow air in and out.

Treatment of Asthma

Asthma management  varies from inhalers to oral medications to drugs delivered in a nebulizer or breathing device. All asthmatic patients are advised to have a good knowledge of asthma medications as well as natural asthma remedies including how first aid measures.treament option depends on — age, symptoms, asthma triggers.

Three Main Type 

A.    RELIEVERS (BRONCHODILATORS)

We have drugs that work to relieve symptoms so their only place is during asthmatic attack, that is they tend to act quickly to dilate the blocked respiratory pathway to promptly relieve the labored breathing. Example of this category is ventolin/salbutamol Inhaler. See others in the list below.

B.   PREVENTERS (ANTIINFLAMMATORY DRUGS)

Some drugs however should be taken daily either you have the attack or not. They are antinflammatory drugs to reduce inflammation which leads to the attack. So the more or the longer you take these drugs, the less frequent you are likely to have asthma attack. So these drugs are for long-term control and to prevent asthmatic attack; they have no place in quick or instantaneous symptomatic relief..

C.   COMBINATION DRUGS (PREVENTERS AND RELIEVERS)-Rational combinations 

There are eight classes of drugs used in the management of asthma

1.   Sympathomimetic agents

2.   Beta-2 selective drugs

3.   Methylxanthine drugs

4.   Antimuscarinic drugs

5.   Leukotriene pathway inhibitors

6.   Corticosteroids

7.   Anti-IgE monoclonal antibodies

8.   Cromolyn and nedocromil

RELIEVERS (BRONCHODILATORS)

Class 1 and 2 above belong to relievers

1.   Sympathomimetic Agents

•  Relax airway smooth muscles
•  Inhibit microvascular leakage
•  Increase mucociliary transport by increasing ciliary activity
•  Activate adenylyl cyclase

Examples are:

•     Epinephrine/Adrenalin (320mcg per puff) or 0.4ml of 1:1000 solution given   subcutaneously.
•     Isoproterenol (80-120mcg per puff).

Limitation: cardiac arrhythmias, tachycardia and tremor

2.   Beta-2 selective Agonists(include short-acting and long-acting)

•       Prompt bronchodilation on administration (within 15-30 min)
•       Act like other sympathomimetics but β2 selective
•       Less adverse effect

Short-acting

•    Old generation- salbutamol, albuterol and terbutaline (1 tablet two or three times  daily)

Short-acting beta agonists can be taken using a portable, hand-held inhaler or a nebulizer — a machine that converts asthma medications to a fine mist — so that they can be inhaled through a face mask or a mouthpiece.

Long-acting

•      New generation-salmeterol (contained in seretide diskus)1 puff (50mcg) every 12 hours
•      Formoterol- 12mcg(1 inhalation) every 12 hours. Do not exceed 24mcg daily

3. Methylxanthines

•  Reduce immune and inflammatory activity of specific cells
•    At high concentrations, inhibits phosphodiesterase enzyme 
• Higher concentrations of cyclic AMP causes relaxation of smooth muscles, reduction in immune activity of specific cells.

Example is:

·        Theophylline- 3-4mg/kg every 6 hours

·        Aminophylline

Side effects: tremor, nervousness with high doses.