Sir,Air leak syndrome (ALS) without underlying lung disease or trauma is known as spontaneous pneumomediastinum (SPM) or Hamman's syndrome. Precipitating factors for nontraumatic SPM include coughing, sneezing, Valsalva maneuver, vomiting, or deep inhalation. There are unusual circumstances causing air leaks including anorexia nervosa, diabetic ketoacidosis, labor, retching, repeated forceful vomiting, forcefully blowing into a bottle, polymyositis, dermatomyositis, and drug inhalation including methamphetamines. This is a 22-year-old physically active Mexican male with no significant medical history, who presented to the emergency department (ED) with chief complaints of shortness of breath and palpitations that started one night before presentation. On further questioning, the patient admitted to deep inhalation of amphetamines for the first time in his life 1 h before the development of these symptoms. The patient denied any history of chest trauma, recent travel, sick contacts, similar kinds of episodes in the past, recent infection, fever, cough, nausea, vomiting, history of peptic ulcers, recent weightlifting, exertion, deep sea diving, vigorous sexual activity, or intravenous drug abuse. On presentation, heart rate was 150 beats/min, blood pressure 140/65 mmHg, respiratory rate 50 breaths/min, and oxygen saturation 98% on room air. On physical examination, the patient was in acute respiratory distress, using accessory muscles with shallow and rapid breaths. Chest radiograph (chest X-ray) showed pneumomediastinum without consolidation or pneumothorax, but there was an ill-defined lucent shadow around the cardiac silhouette; therefore, a computed tomography (CT) scan of chest was done which showed extensive subcutaneous emphysema with pneumomediastinum and pneumopericardium. To further evaluate the source of the air leak, an upper gastrointestinal series was performed with oral contrast which ruled out esophageal perforation. The patient was monitored in the critical care unit. After intravenous fluid therapy, lactic acid levels decreased, and the anion gap began to resolve over the next 18–24 h. A repeat chest radiograph was done to confirm the air leak was not worsening. The patient's symptoms improved and his vitals remained stable during the entire hospital stay. The patient was discharged with an extensive list of activities which could trigger his symptoms and was heavily counseled for refraining from the use of illicit drugs, especially by inhalation. SPM is prevalent among young adults with predisposing and precipitating factors and more commonly seen in patients with asthma, chronic obstructive pulmonary disease, interstitial lung disease, and smokers.[12]SPM has been reported after inhaled illicit drug use, with the proposed mechanism being forceful inhalation leading to high intra-alveolar pressure causing alveolar rupture and pneumomediastinum. This creates a Valsalva effect, triggering the rupture of alveoli and air leakage through the facial planes around the peribronchovascular space.[345] Depending on the number of alveoli involved, the air leak can be significant and can dissect through the mediastinum to enter surrounding closed spaces such as the pericardium, retroperitoneum, and subcutaneous tissue in the neck [Figure 1]. It is rare to have a significant amount of ALS after inhalation of amphetamine for the first time, which is the scenario in our case. Air traversed through ruptured alveoli into the mediastinum, pericardium, and subcutaneous tissue around the neck, which is also known as the Macklin effect.[6] The Müller maneuver is a reverse Valsalva which creates subatmospheric pressure in the chest and lungs when the patient inspires through a device with airflow resistance, which may induce rupture of the alveoli.[7]
Figure 1
Radiographic images of chest
Radiographic images of chestDirect toxicity of drugs and adulterants can lead to hypoxia or impaired oxygenation by damage to the respiratory membrane.[8] Diagnosis is based on history, symptoms, signs, and radiological evidence. In a majority of cases of pneumomediastinum, it may not be easily detected on physical examination unlike pneumothorax. Chest radiograph and CT scan can delineate pneumomediastinum, unless air leak is insignificant. It is imperative to evaluate the extent of air leak in patient with pneumomediastinum. Serial chest radiograms are encouraged to monitor the involvement of lung parenchyma by toxic effects of inhaled illicit drug. Management is conservative; however, the patient should be monitored closely for extension of air leak in tissue planes.
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Figure 1