Pneumothorax Differential Diagnoses

Updated: May 09, 2022
  • Author: Brian J Daley, MD, MBA, FACS, FCCP, CNSC; Chief Editor: Mary C Mancini, MD, PhD, MMM  more...
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Diagnostic Considerations

This section reviews some important points to consider in the diagnosis of pneumothoraces.

Spontaneous pneumothorax

Because patients with primary spontaneous pneumothorax (PSP) will have apical emphysematous pulmonary disease on computed tomography (CT) or thoracoscopy, they can be thought to have a congenital syndrome of mild acinar emphysema, whose expression is enhanced by environmental factors (eg, smoking) just as it is in patients with alpha-1-antitrypsin deficiency and "typical" emphysema.

Folliculin gene disorders have been described in familial spontaneous pneumothorax. [4] These patients may have pneumothorax as the presenting symptom of Birt-Hogg-Dube disease. [5] Some authors recommend screening patients with a family history of pneumothorax for the benign skin tumors and renal cancers that arise from the disease.

Catamenial pneumothorax is a rare cause of recurrent pneumothorax in women. Prior to recurrence, this condition may initially be diagnosed as PSP.

Pneumonia is a possible cause of pneumothorax; in the patient with human immunodeficiency virus infection (HIV), Pneumocystis jiroveci pneumonia (PCP) , toxoplasmosis, and Kaposi sarcoma need to be considered . A patient with HIV can have spontaneous pneumothorax as the presenting symptom of their illness: HIV carries a lifetime risk of 6% for pneumothorax, and about 85% of that number is related to PCP pneumonia.

The rare event of spontaneous pneumothorax leading to tension pneumothorax may be misdiagnosed as an asthma crisis or exacerbation of chronic obstructive pulmonary disease (COPD) in the patient presenting with tachycardia, subcutaneous emphysema, dyspnea, and shock.

Traumatic pneumothorax

Always consider pneumothorax in the differential diagnosis of major trauma. In the patient with blunt trauma and mental status changes, hypoxia, and acidosis, symptoms of a tension pneumothorax may be masked by associated and similarly potentially lethal injuries.

When assessing the trauma patient, be aware that clinical presentations of tension pneumothorax and cardiac tamponade may be similar.

Tension pneumothorax

The diagnosis of a tension pneumothorax should largely be based on the history and physical examination findings. Ultrasonography in the emergency setting is being increasingly used as an adjunct to the physical examination when there is doubt regarding the diagnosis. Chest radiography or CT should be used only in those instances when the clinician is in doubt regarding the diagnosis and when the patient's clinical condition is hemodynamically stable. Obtaining such imaging studies when the diagnosis of tension pneumothorax is not in question causes an unnecessary and potentially lethal delay in treatment.

A tension pneumothorax is a life-threatening condition and requires immediate action (eg, needle thoracostomy or chest tube insertion). However, the clinician should be wary of prematurely diagnosing a tension pneumothorax in a patient without respiratory distress, hypoxia, hypotension, or cardiopulmonary compromise. If the patient's clinical presentation is questionable and if the patient appears stable, the clinician should reexamine the patient and use bedside ultrasonography or request immediate portable chest radiography (or reexamine the chest radiographs if they have already been obtained) to confirm the diagnosis.

A high index of suspicion for tension pneumothorax is recommended in patients on mechanical ventilation with acute onset of hemodynamic instability, difficult ventilation with high inspiratory pressures, and worsening hypoxemia and/or hypercapnia, even with a functioning chest tube in place. Patients at greatest risk of a pneumothorax and/or tension pneumothorax include those with COPD who are using ventilators; those with acute respiratory distress syndrome (ARDS); and those receiving a tidal volume greater than 12 mL/kg, a peak airway pressure greater than 60 cm H2O, or a positive end-expiratory pressure greater than 15 cm H2O. Portable chest radiograph may fail to show the pneumothorax; CT may be required for diagnosis.

Avoid assuming that a patient with a chest tube does not have a tension pneumothorax if he or she has respiratory or hemodynamic instability. Chest tubes can become plugged or malpositioned and cease to function. In addition, improper attachment of a one-way valve to the chest tube may produce tension pneumothorax.

Additional considerations

Other conditions to consider include the following:

  • Aspiration, bacterial, mycoplasmal, and viral pneumonia
  • Asthma
  • Costochondritis
  • Diaphragmatic injuries
  • Esophageal spasm
  • Foreign bodies, trachea
  • Mediastinitis
  • Myocardial ischemia
  • Myocarditis
  • Pericarditis
  • Pleurodynia
  • Pulmonary empyema and abscess
  • Tuberculosis

Differential Diagnoses