Pneumothorax

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Definition

Left pneumothorax. This X-ray is used on clinicalcases.org to illustrate a fictional case history of tension pneumothorax. Note the large, well-demarcated area devoid of lung markings, the tracheal deviation and movement of the heart away from the affected side.

A pneumothorax can be defined as air in the pleural cavity. This occurs when there is a breach of the lung surface or chest wall which allows air to enter the pleural cavity and consequently cause the lung to collapse.

Types of Pneumothorax

Various causes of pneumothoraces exist and each pneumothorax is classified according to its cause.

Primary Pneumothorax

Also referred to as a spontaneous pneumothorax or primary spontaneous pneumothorax. It is characterized by having no clear cause or no known underlying lung pathology.

There may be contributing factors, such as cigarette smoke, family history, the rupture of the bulla (small air-filled sacs in the lung tissue) but these will not cause pneumothorax itself.

Secondary Pneumothorax

Also referred to as a non-spontaneous or complicated pneumothorax. It occurs as a result of an underlying lung pathology such as COPD, Asthma, Tuberculosis, Cystic Fibrosis or Whooping Cough.

Tension or Non-tension Pneumothorax

A pneumothorax can further be classified as tension or non-tension pneumothorax.

A tension pneumothorax is caused by excessive pressure build up around the lung due to a breach in the lung surface which will admit air into the pleural cavity during inspiration but will not allow any air to escape during expiration. The breach acts as a one-way valve. This leads to lung collapse.

The removal of the air is through the surgical incision by inserting an underwater drain in the pleural cavity. This excessive pressure can also prevent the heart from pumping effectively which may lead to shock. A non-tension pneumothorax is not considered as severe as there is no ongoing accumulation of air and therefore there is no increased pressure on the organs and the chest.

Traumatic Pneumothorax

Other causes of a pneumothorax can be trauma or incorrect medical care.

A traumatic pneumothorax is caused by trauma to the lungs. Some of the causes are the following: Stab wound, gunshot, or injury from a motor vehicle accident or any other trauma to the lungs.

A pneumothorax which develops as a result of a medical procedure or incorrect medical care i.e. accidental puncture to the lung during surgery is termed as an iatrogenic pneumothorax.

Causes and Risk Factors

The cause of primary spontaneous pneumothorax is unknown (idiopathic), but established risk factors include:

• Gender
• Smoking (cannabis or tobacco) and,
• Family history of pneumothorax.
  

Secondary spontaneous pneumothorax occurs in the setting of a variety of lung diseases. The most common is a chronic obstructive pulmonary disease (COPD), which accounts for approximately 70% of cases. Known lung diseases that may significantly increase the risk for pneumothorax are:

• COPD
• Cystic fibrosis
• Lung cancer
• Asthma
• Tuberculosis
• Bacterial pneumonia: certain forms of pneumonia caused by staphylococcus, streptococcus and other types of bacteria may cause a lung to collapse.

Other traumatic factors may also lead to pneumothorax and eventually lung collapse:

• Injury or trauma to the chest area: Bullet or stab wounds, fractured ribs, or a blunt force injury can cause the lungs to collapse.
• Certain medical procedures: These include procedures in which the lung may inadvertently be punctured (needle aspiration to drain fluid from the lung, biopsy or the insertion of a large intravenous catheter into a neck vein).
• Activities in which there are sharp changes in air pressure: Flying in an airplane or deep-sea diving may result in a collapsed lung

Signs and Symptoms

• Sudden onset of chest pain - sharp pain worse on inspiration
• Dyspnoea - shortness of breath
• Tachycardia - increased heart rate
• Tachypnoea - increased respiration rate
• Dry cough
• Fatigue
• Signs of respiratory distress -nasal flaring, anxiety, use of accessory muscles
• Hypotension
• Subcutaneous emphysema

Epidemiology

Primary spontaneous pneumothorax occurs most often in people between age 18 - 40 and Secondary spontaneous pneumothoraces occur more frequently after age 60 years. Prevalence of a pneumothorax in a newborn is a potentially serious problem and it occurs in about 1-2% of all births.

The overall person consulting rate for pneumothorax (primary and secondary combined) in the GPRD was 24.0/100 000 each year for men and 9.8/100 000 each year for women. Hospital admissions for pneumothorax as a primary diagnosis occurred at an overall incidence of 16.7/100 000 per year and 5.8/100 000 per year for men and women, respectively. Mortality rates were 1.26/million per year for men and 0.62/million per year for women.

Pathology

The pleural cavity is the region between the chest wall and the lungs. If the air enters the pleural cavity, either from the outside (open pneumothorax) or from the lung (closed pneumothorax), the lung collapses and it becomes difficult for the person to breath. Tissue can form a one way-valve which allows air to enter the pleural cavity, but not to escape, overpressure can build up with each breath (tension pneumothorax). This leads to severe shortness of breath, deviation of the heart and compression on the vena cava leading to shock.

There is a loss of intrapleural negative pressure that can result in a lung collapse. Due to this there is a decrease in vital capacity as well as a decrease in PaO2 which is the main consequence of a pneumothorax. The decrease in PaO2 results from various factors i.e low ventilation-perfusion ratios, anatomic shunts and alveolar hypoventilation. Most patients that suffer from a pneumothorax also have an increase in alveolar-arterial oxygen tension.

Diagnosis

Initially a complete medical and physical examination needs to be conducted.

Auscultation

On examination of the chest with a stethoscope, it will be noted that there is either decreased or absent breath sounds over the area of the affected lung, which may indicate that the lung is not inflated in that particular area.

There is hyper resonance (higher pitched sounds than normal) with percussion of the chest wall which is suggestive of pneumothorax diagnosis.

Imaging

Chest x- rays will then be used to confirm the diagnosis of the pneumothorax. In a supine chest x-ray, a deep sulcus sign is diagnostic and this is characterised by a low lateral costophrenic angle on the affected side. Also, the presence of air outside normal lung airways and movement or shifting of the organs away from the air leak in the thoracic cavity will be indicative of the presence of a pneumothorax.

Ultra sound scan can also provide diagnostic assistance.

Diagram showing a neonate with a right tension pneumothorax. Note the tracheal deviation to the left.

Prognosis

Up to 50% of patients who suffer from a pneumothorax will have another or a recurring pneumothorax. However, there are no long-term complications after successful treatment.

Medical and Surgical Management

Pneumothorax is a medical emergency that needs to be addressed rapidly once diagnosed. The main aim is to relieve the pressure on the lung and allow it to expand. It is of vital importance to try and prevent the recurrence of pneumothorax.

Treatment may be determined by the severity of symptoms and indicators:

1. Acute illness - shortness of breath, tachycardia, reduction in O2 saturation,
2. Presence of underlying lung disease such as COPD
3. estimated size of the pneumothorax on X-ray
4. in some instances – on personal preference of the person involved.

Treatment

There are a variety of treatment options for a spontaneous pneumothorax. It has been shown that intervention has similar results to conservative management of pneumothorax including less days spent in hospital:

• Conservative management with observation until the air is naturally resorbed by the body
• Simple aspiration
• Chest drain placement - Simple chest drain placement alone has a very high rate of recurrence (about 65%) in patients with LAM.
• Heimlich valve (HV) insertion - a lightweight one-way valve designed for the ambulatory treatment of pneumothorax (with an intercostal catheter)
• Pleurodesis through a chest tube - a procedure which obliterates the pleural space to prevent future pneumothoraces.
  • Mechanical (using physical abrasion)
  • Chemical (using talc, doxycycline, bleomycin or other agents). While chemical pleurodesis through a chest tube can be successful, this may result in incomplete pleurodesis due to the uneven distribution of the chemical.
• Surgery - Surgical treatment, using video-assisted thoracoscopy (VATS), is the preferred approach.

Recurrent pneumothorax treatment

For patients with recurrent pneumothorax after surgical intervention, there are several options. For patients with a total or near-total lung collapse, repeat surgical intervention is recommended.

Options include:

• Repeat mechanical pleurodesis if it is unclear whether appropriate mechanical pleurodesis was done initially
• Pleurectomy in which the pleura overlying the ribs is actually removed.
• Chemical pleurodesis in which a drug or other agent is used to create an inflammatory response that results in pleurodesis. Talc is the most commonly used agent due to its effectiveness. Historically, talc pleurodesis was considered a contraindication to future lung transplantation because of the intense inflammatory response that made surgery very difficult.
• Lung transplant

Physiotherapy Management

Indications for Physiotherapy

• Lung collapse
• Sputum retention
• Ventilation/perfusion mismatch (V/Q)
• Increased work of breathing
• Blood gas abnormalities
• Post operative ITU care

Goals for Physiotherapy

1.To improve ventilation and increase PaO2 levels

• Physical activity (stairs, walking, moderate-intensity aerobic exercise)
• Active cycle of breathing exercises
• Sputum removal techniques i.e. percussion, cough assist
• PEP devices
• Incentive spirometry
• Non invasive ventilation (NIV)

2. To assist in sputum removal

• Postural drainage
• Active cycle of breathing exercises
• Percussion, shaking, and vibrations
• PEP devices
• Physical activity (stairs, walking, moderate-intensity aerobic exercise)
• Coughing and huffing (forced expiratory breath)
• Airway suctioning

3. To reduce work of breathing

• Body positioning
• Breathing control
• Relaxation techniques
• Accessory muscle use

4. Improve exercise tolerance

• Early mobilisation and positioning
• Graded exercise program
• Breathing exercises

Physiotherapy outcome evaluation includes

• Respiratory rate
• O2 saturation
• Arterial blood gases
• Additional O2 requirements
• Auscultation
• Chest x-ray
• Mobility status