Asthma Symptoms and Asthma Causes

Asthma Symptoms

Because of the spectrum of severity within asthma, some people with asthma only rarely experience symptoms, usually in response to triggers, where as other more severe cases may have marked airflow obstruction at all times.

Asthma exists in two states: the steady-state of chronic asthma, and the acute state of an acute asthma exacerbation. The symptoms are different depending on what state the patient is in.

Common symptoms of asthma in a steady-state include: nighttime coughing, shortness of breath with exertion but no dyspnea at rest, a chronic throat-clearing type cough, and complaints of a tight feeling in the chest. Severity often correlates to an increase in symptoms. Symptoms can worsen gradually and rather insidiously, up to the point of an acute exacerbation of asthma. It is a common misconception that all people with asthma wheeze—some never wheeze, and their disease may be confused with another chronic obstructive pulmonary disease such as emphysema or chronic bronchitis.

An acute exacerbation of asthma is commonly referred to as an asthma attack. The cardinal symptoms of an attack are shortness of breath (dyspnea), wheezing, and chest tightness. Although the former is often regarded as the primary symptom of asthma, some patients present primarily with coughing, and in the late stages of an attack, air motion may be so impaired that no wheezing may be heard. When present the cough may sometimes produce clear sputum. The onset may be sudden, with a sense of constriction in the chest, as breathing becomes difficult and wheezing occurs (primarily upon expiration, but sometimes in both respiratory phases). It is important to note inspiratory stridor without expiratory wheeze however, as an upper airway obstruction may manifest with symptoms similar to an acute exacerbation of asthma, with stridor instead of wheezing, and will remain unresponsive to bronchodilators.

Signs of an asthmatic episode include wheezing, prolonged expiration, a rapid heart rate (tachycardia), and rhonchous lung sounds (audible through a stethoscope). During a serious asthma attack, the accessory muscles of respiration (sternocleidomastoid and scalene muscles of the neck) may be used, shown as in-drawing of tissues between the ribs and above the sternum and clavicles, and there may be the presence of a paradoxical pulse (a pulse that is weaker during inhalation and stronger during exhalation), and over-inflation of the chest.

During very severe attacks, an asthma sufferer can turn blue from lack of oxygen and can experience chest pain or even loss of consciousness. Just before loss of consciousness, there is a chance that the patient will feel numbness in the limbs and palms may start to sweat. The persons feet may become cold. Severe asthma attacks which are not responsive to standard treatments, called status asthmaticus, are life-threatening and may lead to respiratory arrest and death.

Though symptoms may be very severe during an acute exacerbation, between attacks a patient may show few or even no signs of the disease.

Asthma Causes

Asthma is caused by environmental and genetic factors, which can influence how severe asthma is and how well it responds to medication. Some environmental and genetic factors have been confirmed by further research, while others have not been. Underlying both environmental and genetic factors is the role of the upper airway in recognizing the perceived dangers and protecting the more vulnerable lungs by shutting down the airway. Profet has argued that allergens look to our immune systems like significant threats. Asthma, in this view, is seen as an evolutionary defense. This view also suggests that removing or reducing airborne pollutants should be successful at reducing the problem.

Many environmental risk factors have been associated with asthma development and morbidity in children, but a few stand out as well-replicated or that have a meta-analysis of several studies to support their direct association.

Environmental tobacco smoke, especially maternal cigarette smoking, is associated with high risk of asthma prevalence and asthma morbidity, wheeze, and respiratory infections. Low air quality, from traffic pollution or high ozone levels, has been repeatedly associated with increased asthma morbidity and has a suggested association with asthma development that needs further research.

Recent studies show a relationship between exposure to air pollutants (e.g. from traffic) and childhood asthma. This research finds that both the occurrence of the disease and exacerbation of childhood asthma are affected by outdoor air pollutants.

Caesarean sections have been associated with asthma when compared with vaginal birth; a meta-analysis found a 20% increase in asthma prevalence in children delivered by Caesarean section compared to those who were not. It was proposed that this is due to modified bacterial exposure during Caesarean section compared with vaginal birth, which modifies the immune system (as described by the hygiene hypothesis).

Psychological stress has long been suspected of being an asthma trigger, but only in recent decades has convincing scientific evidence substantiated this hypothesis. Rather than stress directly causing the asthma symptoms, it is thought that stress modulates the immune system to increase the magnitude of the airway inflammatory response to allergens and irritants.

Viral respiratory infections at an early age, along with siblings and day care exposure, may be protective against asthma, although there have been controversial results, and this protection may depend on genetic context.

Antibiotic use early in life has been linked to development of asthma in several examples; it is thought that antibiotics make one susceptible to development of asthma because they modify gut flora, and thus the immune system (as described by the hygiene hypothesis). The hygiene hypothesis is a hypothesis about the cause of asthma and other allergic disease, and is supported by epidemiologic data for asthma. For example, asthma prevalence has been increasing in developed countries along with increased use of antibiotics, c-sections, and cleaning products. All of these things may negatively affect exposure to beneficial bacteria and other immune system modulators that are important during development, and thus may cause increased risk for asthma and allergy.

Recently scientists connected the rise in prevalence of asthma, to the rise in use of paracetamol, suggesting the possibility that paracetamol can cause asthma.