Pneumomediastinum after acute lymphoblastic leukemia and chemotherapy?

Abstract

Pneumomediastinum, pneumorachis and subcutaneous emphysema are frequently benign and most commonly result from air escaping from the upper respiratory tract, intrathoracic airways, or gastrointestinal tract. Gas can also be generated by certain infections or reach the mediastinal space from outside air after trauma or surgery. In the article presented by Showkat et al a 14-year-old male patient with acute lymphoblastic leukemia (ALL) under chemotherapy developed pneumomediastinum, pneumorachis and subcutaneous emphysema. In the author’s opinion, these complications were caused by ALL or chemotherapy that progressed to severe respiratory failure until the patient finally died in the intensive care unit. I would like to underline some important points, which have been raised following a paper published in the October issue of World Journal of Clinical Cases.

Key Words: Acute lymphoblastic leukemia; Pneumomediastinum; Pneumorachis; Chemotherapy; Case report

Core tip: In the article presented by Showkat et al, the authors reported a 14-year-old male with acute lymphoblastic leukemia (ALL) under chemotherapy who developed pneumomediastinum, pneumorachis and subcutaneous emphysema, apparently caused by ALL or chemotherapy in the author’s opinion, and eventually died.

TO THE EDITOR

I read with interest the article presented by Showkat et al[1], where the authors reported a 14-year-old male under chemotherapy for acute lymphoblastic leukemia (ALL) who developed pneumomediastinum, pneumorachis and subcutaneous emphysema of apparently unknown origin. In this case, the doctors assumed that the cause was chemotherapy or ALL, but there are some points I would like to consider.

Pneumomediastinum or mediastinal emphysema is characterized by the entry of air or other gas into the mediastinum most commonly resulting from air escaping from the upper respiratory tract, intrathoracic airways, or gastrointestinal tract. Gas can also be generated by certain infections or reach the mediastinal space from outside air after trauma or surgery (Table 1)[2].

Table 1 Etiology of pneumomediastinum.

Upper respiratory tract

Head and neck infections

Facial bone fractures

Dental procedures

Mucosal disruption

Tracheotomy

Lower respiratory airways

Chest trauma

Foreign body

Neoplasm

Alveolar rupture: trauma, biopsy, surgery, pleurotomy

Wind instrument playing

Scuba diving

Mechanical ventilation

Gastrointestinal tract

Pneumoperitoneum

Pneumoretroperitoneum

Esophageal perforation (e.g., Boerhaave’s syndrome)

Gas producing germs infection

Bacterial mediastinitis

Head and neck infections

Marijuana smoking and cocaine inhalation

Vomiting

Seizures

Coughing, sneezing, hiccupping

Heavy lifting

Air travel

Heimlich maneuver

This particular patient could have been suffering from an idiopathic cause of pneumomediastinum (Hamman’s syndrome)[3], and there are different processes that can explain this condition apart from ALL or chemotherapy: (1) patients who receive chemotherapy frequently vomit and this is a recognized cause of pneumomediastinum; and (2) pneumomediastinum per se is frequently benign but oxygenation in this patient was progressively deteriorating. What was the etiology of his respiratory arrest? Did he develop a tension pneumothorax that could explain the respiratory arrest and the deteriorating respiratory condition? What happened while the patient was in the intensive care unit? What was the cause of death in this patient?

Pneumothorax in the supine patient may be difficult to diagnose and must be considered or it will be missed. Occasionally, tension pneumomediastinum may occur, although this is usually of greater clinical likelihood in pediatric patients. Concomitant pulmonary interstitial emphysema will result in further respiratory embarrassment secondary to compression of lung parenchyma by interstitial air, and decreases in both ventilation and perfusion, especially after mechanical ventilation. Tension pneumopericardium could complicate the presentation and impair venous return and cardiac function[4]. Air embolism or pneumocephalus are infrequent but could be ruled out[4,5]. No computed tomography scans or X-rays were mentioned later in the evaluation. Different investigations are not clear in this case that could help in the diagnosis.

In my opinion, chemotherapy or ALL per se does not explain the mechanism of production of pneumomediastinum, pneumorachis or subcutaneous emphysema. This association was possibly a coexisting condition instead of a complication of ALL or chemotherapy as the authors affirm. Unfortunately, there was no autopsy to establish the final diagnosis.