ETIOLOGY, PATHOGENESIS, PRINCIPLES OF DIAGNOSIS AND TREATMENT OF PNEUMOTHORAX. KOMOLAFE JOYCE OLUSHOLA GROUP 16A Доля Олег Сергійович TABLE OF CONTENTS • What is Pneumothorax? • Primary Spontaneous Pneumothorax • Seconadry Spontaneous Pneumothorax • Etiology of Pneumothorax • Pathogenesis of Pneumothorax • Principle of Diagnosis of Pneumothorax • Treatment of Pneumothorax • References WHAT IS PNEUMOTHORAX? A pneumothorax (noo-moe-THOR-aks) is a collapsed lung. A pneumothorax occurs when air leaks into the space between your lung and chest wall. This air pushes on the outside of your lung and makes it collapse. A pneumothorax can be a complete lung collapse or a collapse of only a portion of the lung. • A pneumothorax can be caused by a blunt or penetrating chest injury, certain medical procedures, or damage from underlying lung disease. Or it may occur for no obvious reason. Hence, if air is present in the pleural space, one of three events must have occurred: 1) communication between alveolar spaces and pleura; 2) direct or indirect communication between the atmosphere and the pleural space; or 3) presence of gas-producing organisms in the pleural space. • Pneumothorax can be classified to Primary Spontaneous Pneumothorax and Secondary Spontaneous Pneumothorax. PRIMARY SPONTANEOUS PNEUMOTHORAX Primary spontaneous pneumothorax (PSP) is defined as the spontaneously occurring presence of air in the pleural space in patients without clinically apparent underlying lung disease. PSP typically occurs in tall, thin subjects. Other risk factors are male sex and cigarette smoking. Contrary to popular belief, PSP typically occurs at rest; avoiding exercise, therefore, should not be recommended to prevent recurrences. Precipitating factors may be atmospheric pressure changes (which may account for the often observed clustering of PSP) and exposure to loud music. Almost all patients with PSP report a sudden ipsilateral chest pain, which usually spontaneously resolves within 24 h. Dyspnoea may be present but is usually mild. Physical examination can be normal in small pneumothoraces. In larger pneumothoraces, breath sounds and tactile fremitus are typically decreased or absent, and percussion is hyper-resonant. Rapidly evolving hypotension, tachypnea, tachycardia and cyanosis should raise the suspicion of tension pneumothorax, which is, however, extremely rare in PSP. SECONDARY SPONTANEOUS PNEUMOTHORAX A multitude of respiratory disorders have been described as a cause of spontaneous pneumothorax. The most frequent underlying disorders are chronic obstructive pulmonary disease with emphysema, cystic fibrosis, tuberculosis, lung cancer and HIV-associated Pneumocystis carinii pneumonia, followed by more rare but “typical” disorders, such as lymphangioleiomyomatosis and histiocytosis X. Because lung function in these patients is already compromised, secondary spontaneous pneumothorax (SSP) often presents as a potentially life-threatening disease, requiring immediate action, in contrast with PSP, which is more of a nuisance than a dangerous condition. The general incidence is almost similar to that of PSP. Depending upon the underlying disease, the peak incidence of SSP can occur later in life, e.g. 60–65 yrs of age in the emphysema population. ETIOLOGY OF PNEUMOTHORAX • A pneumothorax can be caused by: • Chest injury. Any blunt or penetrating injury to your chest can cause lung collapse. Some injuries may happen during physical assaults or car crashes, while others may inadvertently occur during medical procedures that involve the insertion of a needle into the chest. • Lung disease. Damaged lung tissue is more likely to collapse. Lung damage can be caused by many types of underlying diseases, such as chronic obstructive pulmonary disease (COPD), cystic fibrosis, lung cancer or pneumonia. Cystic lung diseases, such as lymphangioleiomyomatosis and Birt-Hogg-Dube syndrome, cause round, thin-walled air sacs in the lung tissue that can rupture, resulting in pneumothorax. • Ruptured air blisters. Small air blisters (blebs) can develop on the top of the lungs. These air blisters sometimes burst — allowing air to leak into the space that surrounds the lungs. • Mechanical ventilation. A severe type of pneumothorax can occur in people who need mechanical assistance to breathe. The ventilator can create an imbalance of air pressure within the chest. The lung may collapse completely. ETIOLOGY OF PNEUMOTHORAX • In general, men are far more likely to have a pneumothorax than women are. The type of pneumothorax caused by ruptured air blisters is most likely to occur in people between 20 and 40 years old, especially if the person is very tall and underweight. • Underlying lung disease or mechanical ventilation can be a cause or a risk factor for a pneumothorax. Other risk factors include: • Smoking. The risk increases with the length of time and the number of cigarettes smoked, even without emphysema. • Genetics. Certain types of pneumothorax appear to run in families. • Previous pneumothorax. Anyone who has had one pneumothorax is at increased risk of another. PATHOGENESIS OF PNEUMOTHORAX The exact pathogenesis of the spontaneous occurrence of a communication between the alveolar spaces and the pleura remains unknown. Most authors believe that spontaneous rupture of a subpleural bleb, or of a bulla, is always the cause of PSP, but alternative explanations are available. Although the majority of PSP patients, including children, present blebs or bullae, it is unclear how often these lesions actually are the site of air leakage. Only a minority of blebs are actually ruptured at the time of thoracoscopy or surgery, whereas often other lesions are present (“pleural porosity”: areas of disrupted mesothelial cells at the visceral pleura, replaced by an inflammatory elastofibrotic layer with increased porosity, allowing air leakage into the pleural space). These lesions may, therefore, predispose to PSP when combined with (largely unknown) precipitating factors; blebs and bullae indeed also occur in up to 15% of normal subjects. PRINCIPLE OF DIAGNOSIS OF PNEUMOTHORAX Diagnosis can be confirmed in the majority of cases on an upright posteroanterior (PA) chest radiograph, which also allows an estimation of the pneumothorax size with good accuracy. In cases with a small PSP, computed tomography (CT) may be necessary to diagnose the presence of pleural air. Routine expiratory chest radiographs are useless. It is important to realise that a contralateral shift of the trachea and mediastinum is a completely normal phenomenon in spontaneous pneumothorax, and not at all suggestive for tension pneumothorax; this observation should therefore in no way influence treatment strategies. Others are: Chest X-rays, Ultrasound Imaging. TREATMENT OF PNEUMOTHORAX Treatment options may include: • observation, • needle aspiration, • chest tube insertion, • nonsurgical repair or surgery. • You may receive supplemental oxygen therapy to speed air reabsorption and lung expansion. REFERENCES • https://www.mayoclinic.org/diseases-conditions/pneumothorax/symptomscauses/syc-20350367 • https://err.ersjournals.com/content/19/117/217 • https://www.youtube.com/watch?v=Bt0axpDlTd8
