Tension pneumothorax

Clinical History

Elderly lady with acute onset shortness of breath and right sided pleuritic chest pain

Imaging Findings

The patient presented with acute shortness of breath and right-sided pleuritic chest pain. She was a smoker. On clinical examination she was alert, tachypnoeic, acyanotic and apyrexial. The trachea was deviated to the right, with decreased air entry on the right, and the right upper chest was more resonant. X-ray examination showed a pneumothorax with pleural tethering, but the most crucial finding on the chest X-ray was the eversion of the anterior costophrenic gutter, which suggested that the pneumothorax was under tension. CT examination of the thorax confirmed subtotal collapse of the right lung. Immediate release of the tension pneumothorax with an 8.5 pigtail catheter drain led to almost complete expansion of the lung.

Discussion

Air in the pleural space is known as pneumothorax. There are several causes of adult pneumothorax, including spontaneous primary and spontaneous secondary (airflow obstruction, pulmonary infection, pulmonary infarction, neoplasm, diffuse lung disease, etc), traumatic and iatrogenic causes. Tension pneumothorax is the one that is life threatening and here intra-pleural pressure becomes positive relative to atmospheric pressure for a significant part of the respiratory cycle. It is usually found in the setting of trauma, but it is important to diagnose this condition immediately, even in the absence of trauma.

The radiographic appearance of a pneumothorax depends critically on radiographic projection, the patient's position and the presence or absence of loculation. Erect chest X-ray in inspiration and expiration is used as the first line of investigation. On a supine film the sensitivity for diagnosis is only 50-70%, depending on the size of the pneumothorax. CT examination of the chest is more sensitive and may be limited to lung bases. Radiographic findings of a tension pneumothorax include a completely collapsed lung, deviation of the trachea, and mediastinal shift to the contra-lateral side. Depression of the diaphragm is a more important and useful observation than mediastinal shift, especially if there is pre-existing tethered pleura.

Tension pneumothorax is unusual in primary pneumothorax and is commonly seen in association with trauma or mechanical ventilation. Treatment is immediate decompression. Complications of pneumothorax include pleural fluid, re-expansion pulmonary oedema, recurrence and pneumomediastinum/pneumoperitoneum. If tension pneumothorax is left untreated it may prove to be fatal.

Differential Diagnosis List

Final Diagnosis

Tension pneumothorax

URL:	https://eurorad.org/case/1373
DOI:	10.1594/EURORAD/CASE.1373
ISSN:	1563-4086