Generality
Bronchospasm is an abnormal and excessive contraction of the smooth muscles that surround the bronchi and bronchioles; it follows a narrowing, if not a complete occlusion, of the respiratory tract.
Those who suffer from bronchospasm struggle to breathe, cough, wheeze during breathing and complain of chest tightness. The presence of the cough is linked to the greater production of mucus by the mucosa of bronchi and occluded bronchioles.
The main causes of bronchospasm are asthma and bronchitis; these two morbid conditions are both inflammatory.
Often, for a definitive diagnosis, the physical examination and the evaluation of the patient's medical history are sufficient.
The therapy is pharmacological and consists of medicines to open the airways (beta2-agonists and anticholinergic bronchodilators) and anti-inflammatory drugs to reduce the inflammatory state (corticosteroids).
Anatomy of bronchi and bronchioles
The bronchi represent the airways following the trachea.
In adult subjects, the trachea bifurcates at the level of the 4th-5th thoracic vertebrae to give rise to the two primary (or main) bronchi, one for the right lung and one for the left lung.
The primary bronchi are subdivided in turn into branches of ever smaller caliber, constituting what in medical jargon is called the bronchial tree .
The bronchial tree consists of airways (or respiratory) external to the lungs (extrapulmonary primary bronchi) and intrapulmonary airways (secondary and tertiary bronchi, bronchioles, terminal bronchioles and respiratory bronchioles).
Similarly to the upper airways (which are: the nasal cavities, the nasopharynx, the pharynx, the larynx and the trachea), the bronchi have the function of transporting the air coming from the external environment to the functional units of the lungs: the so-called alveoli .
Surrounded by a dense network of capillaries, the alveoli are small pockets, which receive the inspired air and allow the blood to "charge" itself with the oxygen needed by the entire organism. It is in the alveoli, in fact, that the oxygen-carbon dioxide gas exchange takes place between the blood, circulating in the capillaries, and the atmospheric air, introduced with respiration.
From the histological point of view, the bronchi-bronchiole system tends to progressively change its structure as it enters more and more into the lungs: in the primary bronchi, the cartilaginous component is superior to the muscular one (there is a remarkable resemblance to the trachea) ; starting from the secondary bronchi and up to just before the alveoli, the muscular component takes over and gradually replaces the cartilage more and more.
What is bronchospasm?
Bronchospasm is the abnormal contraction of the smooth muscles of the bronchi or bronchioles, which causes a narrowing, or in particularly severe cases, complete occlusion of the airways.
Narrowing or total occlusion are usually temporary, so sooner or later there is a restoration of airway patency.
MAIN CONSEQUENCES OF BRONCOSPASM
An individual suffering from bronchospasm struggles to breathe, as there is an impediment to the passage of air through the bronchi and / or bronchioles.
However, the situation is slightly more complex than one might think. In fact, the narrowing or the occlusion induce the bronchial mucosa to produce huge quantities of mucus, which:
- helps to block the air entering the lungs,
- it irritates the inner wall of the bronchi (or bronchioles) inflaming it
- favors the appearance of cough (NB: cough is a defensive mechanism, which serves to expel this obstructive mucus).
Causes
The main causes of bronchospasm are two known and widespread inflammatory conditions of the bronchial tree: asthma and bronchitis .
Asthma is a chronic, probably genetic, morbid state whose symptoms usually become acute after contact with allergens * (eg pollens, food, dust, animal hair, etc.), respiratory infections, medicines (NSAIDs and beta - blockers in particular), physical exertion, excessive emotions, stress and smoking.
Figure: comparison between the respiratory airways of an asthmatic, suffering from bronchospasm, and a healthy individual. You can see the narrowing of the passage for air and the presence of mucus (in yellow). From the site: grosiramazing.com
Infectious agents that can cause bronchitis and, subsequently, episodes of bronchospasm.
- Flu viruses
- Syncytial virus
- Adenovirus
- Haemophilus influenzae
- Streptococcus pneumoniae
- Moraxella catarrhalis
Bronchitis, on the other hand, can be an acute or chronic circumstance, which arises due to respiratory infections (such as cold or flu), cigarette smoke and / or pollution (environmental, domestic or work). Chronic forms of bronchitis represent a morbid state also known as chronic obstructive pulmonary disease ( COPD ).
OTHER CAUSES
In apparently healthy individuals, episodes of bronchospasm may also be caused by:
- The contact or proximity to particular substances (including pollen, dust, food, mold, animal hair, etc.), to which there is an intolerance or an allergy.
- An intense or too high physical activity compared to the possibilities of the individual who carries it out.
- Intake of certain drugs, including antibiotics, NSAIDs and antihypertensives. The possibility of giving bronchospasm is generally linked to an intolerance of the patient towards the aforementioned medicines.
- General anesthesia, practiced in the surgical field, before certain invasive interventions. In such situations, bronchospasm is a complication.
Its establishment follows the doctor's application of the tube used to support the patient's breathing during the operation.
RISK FACTORS
All asthmatic subjects, bronchitics, people exposed to the triggers, bronchitis (infectious diseases, polluted environments, etc.) and individuals allergic to some of the substances mentioned above are obviously at great risk of bronchospasm.
Symptoms and Complications
The symptoms and signs that characterize bronchospasm are:
- Cough . The mechanism that triggers the cough has already been treated.
- Shortness of breath and dyspnea . In people who suffer from asthma or chronic bronchitis, these breathing difficulties generally get worse in the evening, early in the morning or after physical activity.
- Presence of wheezing during breathing . They are abnormal sounds that the patient emits during breathing.
- Thoracic oppression . It is similar to a sense of chest pressure. Sometimes it can look like real pain.
COMPLICATIONS
The clinical manifestations that characterize the presence of severe respiratory difficulties are: dyspnea at rest, cyanosis (usually in the fingers) and an increase in heart rate .
WHEN TO REFER TO THE DOCTOR?
According to the doctors, it is good to turn to them in the presence of:
- Cough that shows no signs of passing
- I gasped during breathing, which, instead of improving, get worse
- Temperature
- Small breathing problems
Furthermore, again based on expert opinion, these are symptoms that require an immediate medical examination:
- He coughed it up with blood
- Dyspnea and cyanosis in the fingers
- Chest pain
- The marked increase in heart rate
Diagnosis
In general, the first diagnostic tests, to which doctors refer in the presence of suspected bronchospasm, are: the objective examination and the evaluation of the clinical history .
These two analyzes are, in many cases, sufficient to establish a precise final diagnosis; however, it may still be necessary to perform more specific instrumental tests, as these also clarify the causes that produced the episode (or episodes) of bronchospasm.
EXAMINATION OBJECTIVE
A thorough physical examination requires the doctor to visit the patient, asking him about the symptoms.
The most common questions - because they are more important for a correct diagnostic analysis - are:
- What are the symptoms?
- When did clinical manifestations appear? Is there an event in particular?
- Are there moments of the day or special situations in which the symptoms become more severe?
CLINICAL HISTORY
When doctors talk about medical history they mean everything that concerns the current and past health status of the patient: from the aforementioned pathologies to the current ones; from the drugs taken at the time of evaluation to those hired up to a few weeks before; from any surgical operations to which he may have been subjected to the substances to which he is allergic; etc.
In the presence of a symptom due to bronchospasm, it is particularly important for the patient to communicate to the doctor any presence of:
- Asthma
- Allergies
- Acute bronchitis
- Chronic bronchitis (chronic obstructive pulmonary disease)
INSTRUMENTAL TESTS
The instrumental tests, which doctors use to reach a definitive diagnosis and investigate the triggering causes, are:
- Rx-chest . Provides a fairly clear picture of the lungs and other structures inside the chest. Show any signs of a lung infection. It is a painless but minimally invasive test, as it exposes the patient to a (very low) dose of ionizing radiation.
- Spirometry . Fast, practical and painless, spirometry records the inspiratory and expiratory capacity of the lungs, and the patency (ie, opening) of the airways passing through them.
- CT scan (computerized axial tomography) . It provides very exhaustive three-dimensional images of the organs contained in the thoracic cavity. It is therefore able to show most of the abnormalities that can affect the lungs (signs of infection, signs of inflammation, etc.).
It provides the patient's exposure to a non-negligible dose of ionizing radiation, therefore it is considered an invasive test (although completely painless).
In certain circumstances, to increase the quality of the images, the doctor gives a contrast agent in the patient's circulatory stream. If used, this substance increases the level of invasiveness of the examination, as it can trigger an allergic reaction (NB: this generally occurs in those predisposed).
Treatment
Bronchospasm therapy consists of the administration of drugs aimed at opening the airways and reducing the inflammatory state of the bronchi and bronchioles.
The drugs used include: beta2-agonists, anticholinergic bronchodilators and inhaled corticosteroids .
BETA2-AGONIST
Beta2-agonists are noradrenaline derivatives.
These drugs are particularly suitable for alleviating the symptoms that characterize acute asthma attacks, as they are able to release the smooth muscles of bronchi and bronchioles in a very short time.
Effective even when the causes are not asthmatic in nature, the most commonly used beta2-agonists are:
- Salbutamol
- Salmeterol
- Formoterol
Note: beta2-agonists do not reduce the inflammatory status of the bronchial tree; therefore their action is limited to improving the symptomatic picture.
ANTICOLINERGIC BRONCODILATORS
As you can guess from the name, anticholinergic bronchodilators dilate the respiratory tract, acting on the bronchial muscles. The ultimate goal of their intake is to allow the patient to breathe better.
There are two categories of anticholinergic bronchodilators: short-term anticholinergic bronchodilators and long-lasting ones . The first come into action in a very short time, which makes them particularly suitable for acute bronchospasm episodes; the latter act longer, which makes them suitable medicines to prevent future episodes of bronchospasm.
The most administered anticholinergic bronchodilators include ipratropium bromide and isoetarin.
Note: like beta2-agonists, anticholinergic bronchodilators only relieve symptoms (they do not improve the inflammatory state that can affect bronchi and bronchioles).
CORTISTEROIDS THROUGH INHALATION (OR INHALATORS)
Belonging to the category of steroid drugs, inhaled corticosteroids reduce inflammation of the respiratory tract. Their use allows the patient to breathe better and relieve breathing difficulties.
Like all other steroid drugs, inhaled corticosteroids, if taken in excessive doses or for long periods of time, also cause various side effects, some of which are also very serious.
Possible side effects of steroid drugs.
- Hypertension
- Diabetes
- Bone weakening or osteoporosis
- Glaucoma
- Overweight or obesity
- Gastric ulcers
Prognosis
The prognosis depends on the causes of bronchospasm.
If the triggers are of mild severity, the control of the bronchospasm is also simpler and the risk of complications is lower.
If the triggering factors are particularly severe, the treatment of bronchospasm is more complex (it must first be timely) and the risk of complications is much higher.
Prevention
- Avoid contact with allergens that can trigger an asthma attack;
- warm up properly before any physical activity of a certain entity;
- avoid contact with people with some infectious airway disease (flu, pneumonia, etc.);
- protect yourself adequately while in polluted environments.
These are some of the most important preventive measures against the onset of bronchospasm.
