Respiratory system diseases ppt - د.ظاهر

Pneumothorax

Pneumothorax
It is a significant global health problem, with a reported incidence of 18–28/100 000 cases per annum for men and 1.2–6/100 000 for women.The term ‘pneumothorax’ was first coined by Itard and then Laennec in 1803 and 1819 respectively, and refers to air in the pleural cavity (ie, interspersed between the lung and the chest wall). At that time, most cases of pneumothorax were secondary to tuberculosis, although some were recognised as occurring in otherwise healthy patients (‘pneumothorax simple’).

Pneumothorax

Secondary spontaneouse (SSP) is associated with underlying lung disease, in distinction to primary spontaneous pneumothorax, PSP. Although tuberculosis is no longer the commonest underlying lung disease in the developed world,the consequences of a pneumothorax in patients with pre-existing lung disease are significantly greater, and the management is potentially more difficult.

Pneumothorax

Traumatic pneumothorax results from penetrating or blunt trauma. Iatrogenic pneumothorax may follow procedures such as thoracentesis, pleural biopsy, subclavian or internal jugular vein catheter placement, percutaneous lung biopsy, bronchoscopy with transbronchial biopsy, and positive-pressure mechanical ventilation.

Pneumothorax

Primary pneumothorax affects mainly tall, thin boys and men between the ages of 10 and 30 years. It is thought to occur from rupture of subpleural apical blebs in response to high negative intrapleural pressures. Family history and cigarette smoking may also be important factors. Secondary pneumothorax occurs as a complication of COPD, asthma, cystic fibrosis, tuberculosis, Pneumocystis pneumonia, menstruation (catamenial pneumothorax), and a wide variety of interstitial lung diseases.

Clinical Findings of Pneumothorax

Chest pain ranging from minimal to severe on the affected side and dyspnea occur in nearly all patients. Symptoms usually begin during rest and usually resolve within 24 hours even if the pneumothorax persists. Alternatively, pneumothorax may present with life-threatening respiratory failure if underlying COPD or asthma is present. If pneumothorax is small (less than 15% of a hemithorax), physical findings, other than mild tachycardia, are unimpressive.

Clinical Findings of Pneumothorax
If pneumothorax is large, diminished breath sounds, decreased tactile fremitus, and decreased movement of the chest are often noted. Tension pneumothorax should be suspected in the presence of marked tachycardia, hypotension, and mediastinal or tracheal shift.

Because the ratio of extrapulmonary gas to solid tissue increases in a pneumothorax, hyperresonant percussion notes are produced over the affected area.

Breath sounds diminish as gas accumulates in the intrapleural space.

How to investigate patient with suspected Pneumothorax
A-LABORATORY FINDINGS: Arterial blood gas analysis is often unnecessary but reveals hypoxemia and acute respiratory alkalosis in most patients. Left-sided primary pneumothorax may produce QRS axis and precordial T wave changes on the ECG that may be misinterpreted as acute myocardial infarction.

How to investigate patient with suspected Pneumothorax

B-IMAGINGDemonstration of a visceral pleural line on chest radiograph is diagnostic and may only be seen on an expiratory film. A few patients have secondary pleural effusion that demonstrates a characteristic air-fluid level on chest radiography. In supine patients, pneumothorax on a conventional chest radiograph may appear as an abnormally radiolucent costophrenic sulcus (the “deep sulcus” sign).

Imaging for Pneumothorax

Standard erect PA chest x-ray. Lateral x-rays. Expiratory films. Supine and lateral decubitus x-rays. Ultrasound scanning. Digital imaging. CT scanning.

Depth of pneumothorax.

MacDuff A et al. Thorax 2010;65:ii18-ii31
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Pneumothorax

How to investigate patient with suspected Pneumothorax

B-IMAGING…… In patients with tension pneumothorax, chest radiographs show a large amount of air in the affected hemithorax and contralateral shift of the mediastinum.

Left-sided pneumothorax (arrows). Note the shift of the heart and mediastinum to the right away from the tension pneumothorax.

Differential Diagnosis of Pneumothorax

If the patient is a young, tall, thin, cigarette-smoking man, the diagnosis of primary spontaneous pneumothorax is usually obvious and can be confirmed by chest radiograph. In secondary pneumothorax, it is sometimes difficult to distinguish loculated pneumothorax from an emphysematous bleb. Occasionally, pneumothorax may mimic myocardial infarction, pulmonary embolization, or pneumonia

Treatment of Pneumothorax

Treatment depends on the severity of pneumothorax and the nature of the underlying disease. In a reliable patient with a small (< 15% of a hemithorax), stable spontaneous primary pneumothorax, observation alone may be appropriate. Many small pneumothoraces resolve spontaneously as air is absorbed from the pleural space; supplemental oxygen therapy may increase the rate of reabsorption.

Treatment of Pneumothorax

Simple aspiration drainage of pleural air with a small-bore catheter (eg, 16 gauge angiocatheter or larger drainage catheter) can be performed for spontaneous primary pneumothoraces that are large or progressive. Placement of a small-bore chest tube (7F to 14F) attached to a one-way Heimlich valve provides protection against development of tension pneumothorax and may permit observation from home. The patient should be treated symptomatically for cough and chest pain, and followed with serial chest radiographs every 24 hours.

Treatment of Pneumothorax

Patients with secondary pneumothorax, large pneumothorax, tension pneumothorax, or severe symptoms or those who have a pneumothorax on mechanical ventilation should undergo chest tube placement (tube thoracostomy). The chest tube is placed under water-seal drainage, and suction is applied until the lung expands. The chest tube can be removed after the air leak subsides.

Treatment of Pneumothorax

All patients who smoke should be advised to discontinue smoking and warned that the risk of recurrence is 50%. Future exposure to high altitudes, flying in unpressurized aircraft, and scuba diving should be avoided. Indications for thoracoscopy or open thoracotomy include recurrences of spontaneous pneumothorax, any occurrence of bilateral pneumothorax, and failure of tube thoracostomy for the first episode (failure of lung to reexpand or persistent air leak). Surgery permits resection of blebs responsible for the pneumothorax and pleurodesis by mechanical abrasion and insufflation of talc.

Treatment of Pneumothorax

Management of pneumothorax in patients with Pneumocystis pneumonia is challenging because of a tendency toward recurrence, and there is no consensus on the best approach. Use of a small chest tube attached to a Heimlich valve has been proposed to allow the patient to leave the hospital.