Bullous Emphysema : It is a disease related to air sacs located inside the lungs. As we all know, when we breathe, air passes through the nose and then enters the trachea and eventually travels through the bronchial tubes. These bronchial tubes perform an important task of regulating air flow in the lungs. Inhaled air moves in and out of the lungs through these bronchial tubes. Detailed examination of the airways reveals that the bronchial tubes form a tree like the inner structure of the lungs.
The two bronchi that enter the left and right lungs, respectively, branch off, thus making way for the small bronchial tubes. These subdivisions of the bronchi end at a point known as air sacs (alveoli) that appear as a cluster of grapes. Believe it or not, but our lungs contain more than 600 million alveoli.
Summary
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- 1 Definition
- 2 Risk Factors
- 3 Causes
- 4 Pathological anatomy
- 1 Type I bullas
- 2 Type II bullas
- 3 Type III bullas
- 5 Clinical picture
- 6 Diagnosis
- 7 Treatment
- 8 Complications
- 9 Source
Definition
Bullous emphysema consists of pulmonary parenchymal disorders that involve one or more bullae (intraparenchymal air spaces), represent a special form of emphysema, and are associated with different types of lung lesions. The most common association is with COPD. They are also usually associated with paraseptal emphysema or para- scar emphysema , as in the case of pneumoconiosis .
The bullae are larger than 1 cm in diameter, and should be distinguished from pleural vesicles (blebs) which are collections of air 1-2 cm in diameter within the visceral pleura , and from cysts, which are abnormal air spaces lined with epithelium. Examples of the latter are the bronchogenic cyst and the residual cavity that persists after a lung abscess . They can be asymptomatic and detected casually on an Rx exam.
Risk factor’s
Factors that increase the risk of developing emphysema are:
Smoking : Emphysema is more likely to develop in cigarette smokers, but cigar and pipe smokers are also susceptible. The risk for all types of smokers increases with the number of years and the amount of tobacco smoked.
Age : Although the lung damage that occurs in emphysema develops gradually, most people with tobacco-related lung emphysema begin to experience symptoms of the disease between the ages of 40 and 60.
Exposure to second-hand smoke: Second-hand smoke, also known as passive or environmental tobacco smoke, is smoke that you inadvertently inhale from another person’s cigarette, pipe, or cigar. Being around secondhand smoke increases the risk of emphysema.
Occupational Exposure to Vapors or Dust : If you breathe in smoke from certain chemicals or dust from cereal, cotton, wood, or mining products, you are more likely to develop emphysema. This risk is even greater if you smoke.
Exposure to Indoor and Outdoor Pollution : Breathing indoor pollutants, such as heating fuel vapors, as well as outdoor pollutants – car leaks, for example – increases the risk of emphysema.
Causes
In most cases, people diagnosed with this respiratory problem have a habit of smoking.
Viral or bacterial infections of the lungs such as bronchitis can also lead to bullous emphysema.
In chronic bronchitis, the passages through which air moves freely to and from the lungs do not function properly. This is because in this state, the tube walls swell, thus narrowing the air passages in the lungs. Therefore, inhaling air through partially blocked airways can also cause inflamed air sacs.
Air pollution is another problem, which we face in our day to day life, which can damage the lungs and eventually cause this respiratory problem.
Pathological anatomy
The bullae are localized areas of emphysema that contain hyperinflated alveoli and unstructured septa within. The bullae can be single or multiple, present in normal lungs, or be part of a generalized emphysema. Three anatomical types are distinguished.
Type I bullas
They are subpleural and occur in the absence of emphysema. They communicate with the lung through a narrow neck, have thin walls, and are preferably located at the pulmonary vertices. In its development, a valve mechanism intervenes that causes the progressive entrapment of air, being able to acquire a large size and compress neighboring structures.
Type II bullas
They have a wide neck and contain lung tissue with panacinar emphysema. They are more frequent on the anterior surface of the middle lobe.
Type III bullas
They have a very broad base, contain expanded panacinar emphysema and can be located anywhere in the lung. The distinction between the three types of bullae is of clinical importance, since type I bullae appear in normal lungs, where they can cause alterations due to displacement of structures and compression of the parenchyma. On the contrary, bullas of types II and III appear in the presence of panacinar emphysema, so it can be difficult to differentiate the pathophysiological alterations due to the bulla or those associated with this disease.
Clinical picture
In the initial stages, the affected person may not experience any symptoms, but as the disease progresses, respiratory problems are likely to occur.
When the inflammation spreads over a large number of air sacs, emphysema symptoms are bothersome.
- Shortness of breath: This is an indication that inflammation of the air sacs interferes with the normal function of the lungs.
- Chest pain: This chest discomfort can be persistent or occur intermittently, depending on the severity of the condition.
- Cough with spectoration: As the condition worsens, the person may develop a cough with phlegm.
- Wheezing: The patient may also experience wheezing, which is nothing more than a kind of noise produced during breathing. Persistent wheezing is linked to respiratory problems and often indicates narrow airways.
Diagnosis
Physical examination of a patient with bullous emphysema may be normal or a decrease in vesicular murmur in the area of the bulla may be heard.
On radiographic examination, the characteristic image consists of an avascularized area, well delimited by linear shadows that mark the walls of the bulla. These images are more evident on expiration radiographs, since the air trapped inside the bullas highlights their characteristics. Adjacent vascular structures may be compressed or displaced.
The CT is of great importance in the assessment of bullous emphysema since it allows to better define the bullae, define the volume they occupy, detect if there is parenchymal compression in the adjacent regions and reveal signs of emphysema in the rest of the lung parenchyma.
The study of respiratory function is useful in evaluating the effect of bulla on the lung parenchyma and in detecting underlying emphysema. The bullae in patients with normal lungs cause little functional alteration, behaving only as a space-occupying lesion. If the bulla does not have bronchial communication, the lung volumes measured by plethysmography will be higher than those measured by dilution of helium. The difference between both measurements allows estimating the volume of the air contained inside the bulla. In COPD-associated bullae, the value of DLCO and arterial gases, as well as the presence of signs of pulmonary hypertension , allow us to estimate whether there is severe emphysema in the rest of the lung parenchyma.
The ventilation and perfusion scintigraphy contributes to define the characteristics of the bullae and the rest of the parenchyma.
Treatment
Asymptomatic patients do not require specific treatment. Smoking cessation should be advised and the nature of the process should be reported, as well as clinical follow-up to detect possible symptoms or complications.
Some patients with large bullae (greater than 30% of a hemothorax ) that cause symptoms may benefit from surgical treatment. In patients with localized bullae and the rest of the normal lung parenchyma, the surgical indication will be based on the development of symptoms attributable to the increase in the size of the bulla with compression of the lung parenchyma, the presence of complications or the appearance of respiratory failure due to noise.
In patients with COPD-associated bullae, the surgical indication is restricted to cases with a marked alteration of ventilatory function due to the compressive effect of the bulla and in which the underlying parenchyma is re-expandable, which occurs in a very small number of cases. The evaluation of these cases is complex and must be carried out in centers with experience. A detailed study including chest CT , pulmonary ventilation and perfusion scintigraphy , and respiratory function examination should be performed in these patients .
Patients who could benefit from surgical treatment are those with severe airflow limitation (FEV1 less than 50% of the reference value), in whom CT shows areas of compressed parenchyma and rules out severe emphysema in the rest of the lung parenchyma. As in lung volume reduction surgery (see Chronic obstructive pulmonary disease), patients with severely decreased DLCO, hypercapnia, and signs of pulmonary hypertension are not candidates for surgical bulla , since in these cases emphysema is usually be very pronounced and diffusely affect the entire lung.
Complications
Some of the complications are:
- Infection
- Pneumothorax
- Hemorrhag
