**2. Epidemiology**

Pneumothorax is defined as the presence of air in the pleural space. For air to enter into the pleural space from the capillary blood would require pleural pressure lower than −54 mmHg (< −36 cm H2O), which is difficult to obtain in normal circumstances [16].

If air is present in the pleural space, some of these events may have occurred:

1.Communication between alveola and pleura


PSP has an incidence of 7.4 to 18 cases per 100,000 population each year in males and 1.2 to 6 cases per 100,000 populations each year in females [17, 18]. Risk factors for PSP include tall thin people, male sex, and smoking. The recurrence range is 25–50%, and most recurrences occur in the first year [19]. Female gender, tall male, low body weight, and persistent smoking are associated with a high rate of recurrence [20]. In the largest epidemiologic study of PSP from Bobbio et al. with 42,595 patients, they found that the mean age was significantly greater in women than in men (41 ± 19 vs. 37 ± 19 p < 0.0001), rehospitalization was more frequent in women than in men in patients aged <50 years (p < 0.0001). In the 50–64 years age group, surgical procedures and rehospitalizations were more frequent in men than in women (p = 0.002 and p < 0.0001, respectively). The most commonly performed procedures were thoracoscopic resection of blebs (52% of cases) and talc pleurodesis (24% of cases). Surgery was associated with younger age, secondary pneumothorax, and ICU surveillance (p < 0.001) [21]. Moderate smoking (22 cigarettes/day) increases the risk of first episode of PSP up to 22 times. PSP usually occurs at rest, so the lack of physical activity should be avoided in the counseling of these patients [17]. Thoracic endometriosis may lead to catamenial pneumothorax and should be considered in women with PSP temporally related to menstruation [22]. Malnutrition in patients with anorexia nervosa may lead to the development of PSP. Birt-Hogg-Dubé syndrome (which predisposes patients to benign skin tumors and renal cancers) is an autosomal dominant condition defined as a rare cause of PSP [23]. Precipitating factors include atmospheric pressure changes and exposure to loud music [24, 25].

An increased frequency of PSP is seen in patients with Marfan syndrome and homocystinuria. Marfan syndrome is a common inherited connective tissue disorder with typical skeletal, ocular, and cardiovascular manifestations. Pulmonary involvement occurs less frequently, with PSP being the most frequently reported. Karpman et al.'s study in 2011 found a prevalence of pneumothorax in patients with Marfan syndrome between and 11%. The increased risk of pneumothorax has been attributed to the presence of apical blebs, bullae, and abnormal connective tissue constituents in the lung parenchyma or increased mechanical stresses in the lung apices due to the tall body habitus. Patients who have Marfanoid features such as long stature, hyperextendable joints, and dislocated lens should be studied by CT scanning to identify blebs and bullae. This may allow risk stratification for pneumothorax in patients with this syndrome and also favors identification of aortic root disease, which leads to aneurysmal dilation, aortic regurgitation, and dissection [26, 27]. A multidisciplinary approach is fundamental in these patients and their family, who must be thoroughly investigated, to confirm the disease and to initiate the treatment, thus decreasing mortality, especially due to cardiovascular causes; also a medical genetics consultation should be provided for genetic counseling [28].

PSP recurrence rates are typically cited as between 16 and 52%, which makes counseling about future risk difficult and creates uncertainty regarding the optimal management. Thoracic Society guidelines advise that pneumothorax recurrence is an indication for surgery (whether second ipsilateral or first contralateral) [29]. Unfortunately, there is no consensus on which treatment offers the best reduction in risk of recurrence [6]. A systematic review demonstrates a 32% PSP recurrence rate, with almost all the risk in the first year. Recurrence rates

**17**

*Primary Spontaneous Pneumothorax, a Clinical Challenge*

did not differ based on the initial intervention for PSP. Female sex was associated with higher risk, suggesting possible sex-specific pathophysiology. Also lower BMI and radiological evidence of dystrophic lungs were associated with higher risk of recurrence (bullae on computed tomography (CT) and pleural thickening on chest radiography), until smoking cessation was associated with a fourfold

Symptoms in primary spontaneous pneumothorax may be minimal or absent. These clinical symptoms depend on proportion and the size of the pneumothorax. Patients may present an abrupt onset of pleuritic chest pain associated with dyspnea and shortness of breath, and some patients may experience shoulder tip pain [29]. Severe symptoms are not common, and when this happens it suggests a tension pneumothorax. Typical examination findings in primary spontaneous pneumothorax include ipsilateral decreased breath sounds on auscultation, percussion hyperresonance, and thoracic hypoexpansion. The presence of observable breathlessness has influenced subsequent management in previous guidelines [29, 31]. Hemodynamic compromise is unusual in PSP. Arterial blood gas measurements are frequently abnormal in patients with pneumothorax. Arterial oxygen tension is lower according to the extent of the pneumothorax but oxygen saturations are adequate, and pulmonary function tests are poor predictors of the presence or size

The clinical features in tension pneumothorax are shortness of breath, dyspnea, tachypnea, respiratory distress, hypoxemia, hypotension, tachycardia and ipsilateral decreased air entry, and percussion hyperresonance. This condition requires an urgent thoracic decompression when the diagnosis is suspected, and the clinicians should be prepared to perform urgent thoracic decompression without chest

The diagnosis of pneumothorax is usually confirmed by imaging techniques such as PA chest radiograph, and the excess radiation dose should be avoided in this young patient population. The diagnostic hallmark is the displacement of the pleural line. The pneumothorax is most frequently seen at the lung apex, but lateral, subpulmonic, and medial collections of air can also be seen [33]. Chest X-ray is the first diagnostic evaluation imaging being used, but small-sized pneumothoraces or loculated pneumothoraces can be missed on chest X-ray. If a pneumothorax is suspected and is unrevealed on chest X-ray, a more specific diagnostic imaging like

Ultrasound is a sensitive technique in the evaluation of respiratory diseases and was first used to diagnose pneumothorax in humans in 1987. Ultrasound is commonly used in emergency department with trauma patients and show significantly higher and quicker diagnostic accuracy than chest radiographs in these patients

*DOI: http://dx.doi.org/10.5772/intechopen.83458*

decrease in risk [30].

**3. Clinical presentation**

of a pneumothorax [32].

**4. Diagnosis**

**4.1 Plain chest X-ray**

**4.2 Ultrasonography**

radiographic confirmation in these patients [31].

chest computed tomography (CT) is necessary [34].

[35]. The routine use of ultrasound in PSP is not established.

did not differ based on the initial intervention for PSP. Female sex was associated with higher risk, suggesting possible sex-specific pathophysiology. Also lower BMI and radiological evidence of dystrophic lungs were associated with higher risk of recurrence (bullae on computed tomography (CT) and pleural thickening on chest radiography), until smoking cessation was associated with a fourfold decrease in risk [30].
