Joined: 05 Feb 2006
Location: Devon, UK
|Posted: Sun Feb 05, 2006 1:42 pm Post subject: What is a spontaneous pneumothorax?
Defined as the presence of air in the pleural cavity, can be classified as spontaneous, and traumatic. Spontaneous pneumothorax can be subdivided into primary spontaneous and secondary spontaneous pneumothorax. Secondary spontaneous pneumothorax is associated with an underlying lung pathology.
The condition known as spontaneous pneumothorax is a lung collapse without evidence of trauma (punctures/wounds etc.) to the chest. The condition most often occurs without obvious underlying lung disease. In this instance, it is known as PSP or Primary Spontaneous Pneumothorax. In most cases, primary spontaneous pneumothorax results from the rupture of blebs (air-filled sac on the lung). As a result, air escapes from the lung and enters the chest cavity causing the lung to collapse. Depending on the severity of the incident, various symptoms will be experienced within minutes of the initial collapse. The reason why this occurs is unclear, Spontaneous pneumothoraces are reported in young people with a tall stature. As men are generally taller than women, there is a preponderance among males. The reason for this association, while unknown, is hypothesized to be the presence of subtle abnormalities in connective tissue. smokers are also at higher risk; and in some cases, women during their menstrual cycles.
A primary spontaneous pneumothorax usually develops at rest, and many affected individuals do not seek medical attention for days after symptoms develop.
A life threatening condition that results from a progressive deterioration and worsening of a simple pneumothorax, associated with the formation of a one-way valve at the point of rupture. Upon inspiration, when the pressure inside the chest and pleural cavity lessens as a result of the respiratory muscles increasing chest dimensions, air is sucked in through this one way valve, into the pleural space. Because expiration is a passive process, there is an insignificant amount of pressure created to force the air back out of the pleural cavity. This condition over time results in a gradual accumulation of air to the degree that it begins to put pressure on the mediastinum, compressing the heart and decreasing cardiac output due to the reduced amount of diastolic filling of the ventricles, and also putting pressure against the trachea, deviating it from the midline. Because of the increased thoracic pressure, venous return to the heart is decreased, causing a backup of blood into the venous system, as is evidence by distended jugular veins.
This is a rare syndrome of recurrent pneumothorax in menstruating women. Eighty cases were found in a review of the literature from 1958 to 1995. Its pathogenesis is not fully established. Subpleural endometrial implants reaching the thorax via diaphragmatic defects are the most likely explanation.
Patients usually present with chest pain and shortness of breath in the first 24 to 48 hours of menstruation. Most of the time, the symptoms are on the right side, as is the pneumothorax, and concurrent symptoms of endometriosis may be present. No symptoms occur between menses. Radiographic features are indistinguishable from those of primary spontaneous pneumothorax. Treatment is aimed at the ectopic endometrium and can be achieved by ovulation suppression with oral contraceptives. Surgical intervention is rarely needed.
Familial spontaneous pneumothorax
A rare condition and inherited in two modes: autosomal dominant and X-linked recessive with incomplete penetrance. This condition may be a complication of certain diseases, such as alpha-1-antitrypsin deficiency, Marfan syndrome, Ehlers-Danlos syndrome, or it may occur as an isolated familial disorder.
Spontaneous pneumothorax is seven times more likely to occur in males than females. Male smokers have 22 times the rate of spontaneous pneumothorax compared to nonsmoking males. Female smokers have a 9 times increase in the rate of a SP compared to nonsmoking females . A SP is most likely to occur during the fall or winter months.
In the US: Incidence of primary spontaneous pneumothorax (age adjusted) is 7.4 cases per 100,000 persons per year for men and 1.2 cases per 100,000 persons per year for women.
If left untreated, recurrence rates of a spontaneous pneumothorax are high. Same side recurrence rates as high as 30% at six months and up to 50% at 2 years, without treatment have been reported.
In some instances when the collapse is not severe a patient may decide to let it recover untreated, full re-expansion can take 2-4 weeks for a small to moderate pneumothorax. Large SPs can take 2-3 months to fully re-inflate without any intervention. The average re-expansion rate is 1.25% per day, this can be increased with oxygen treatment.
Causes of pneumothorax may include the following:
• Rupture of subpleural apical emphysematous blebs (accumulation of air between the layers of the visceral pleura that is not confined by connective tissue septa). It is suggested that elastic fibers of blebs and bullae are degraded due to an imbalance between elastase and alpha-1-antitrypsin.
• Smoking (increases the risk of a first spontaneous pneumothorax by more than 20-fold in men and by nearly 10-fold in women, compared with the risks in nonsmokers).
• Physical height (Alveoli are subjected to a greater mean distending pressure over time, leading to subpleural bleb formation; since pleural pressure is more negative at the apex of the lung, blebs are more likely to rupture and cause pneumothorax).
A study From the Second Department of Surgery, Shiga University of Medical Science, Otsu, Japan - concluded that the rapid increase in the vertical dimension of the thorax compared with the horizontal dimension during the period of rapid physical development is considered to affect intrathoracic pressure at the apex of lung, which would have some influence on enhancing cyst formation.
Symptoms of a collapsed lung include:
• Sudden shortness of breath
• Painful breathing
• easy fatigue
• Sharp chest pain, often on one side
• stabbing sensation in the back
• pain in the arm
• Chest tightness
• Dry, hacking cough
• Rapid heart rate
Symptoms of a tension pneumothorax are similar and might also include:
• Bluish color skin (because of a lack of oxygen)
• Engorgement of the neck veins
• Low blood pressure or shock
The following signs can indicate that you have a collapsed lung:
• Low blood pressure
• Rapid heart rate
• Low levels of blood oxygen
• Loss of normal breath sounds in the part of the chest where the lung is deflated
• A hollow sound when the fingers are tapped on part of the chest
• A shift in the normal location of heart sounds