|Year : 2016 | Volume
| Issue : 1 | Page : 16-18
Tension Pneumomediastinum in a Patient with H1N1 Pneumonia: A Rare Case Report
Chenna Keshava1, Sreekar Balasundaram2, Maria Denzil3
1 Consultant Intensivist, M S Ramaiah Memorial Hospital, Bengaluru, Karnataka, India
2 Consultant Cardiothoracic Surgeon, Columbia Asia Referral Hospital, Bengaluru, Karnataka, India
3 Department of Cardiothoracic Surgery, Columbia Asia Referral Hospital, Bengaluru, Karnataka, India
|Date of Web Publication||15-Nov-2016|
Consultant Intensivist, M S Ramaiah Memorial Hospital, Bengaluru, Karnataka
Source of Support: None, Conflict of Interest: None
We report here the case of a 28-year-old pregnant woman who developed adult respiratory distress syndrome, ventilator-associated injury, and sepsis following H1N1 virus infection. She presented with rapidly worsening breathlessness and a 4-day history of fever. Initial computed tomography scan of the chest showed right mid and lower zone alveolar infiltrates. Immediate postadmission, she was tachypneic and required high concentration oxygen to maintain saturations. The patient recovered following prolonged ventilator support, moderate inotrope support, and 6 weeks of hospital stay. The study highlights the significance of prompt diagnosis and management of tension pneumomediastinum to prevent any life-threatening complications.
Keywords: H1N1 pneumonia, pneumomediastinum, pregnant, tension
|How to cite this article:|
Keshava C, Balasundaram S, Denzil M. Tension Pneumomediastinum in a Patient with H1N1 Pneumonia: A Rare Case Report. J Cardiothorac Trauma 2016;1:16-8
|How to cite this URL:|
Keshava C, Balasundaram S, Denzil M. Tension Pneumomediastinum in a Patient with H1N1 Pneumonia: A Rare Case Report. J Cardiothorac Trauma [serial online] 2016 [cited 2020 Aug 7];1:16-8. Available from: http://www.jctt.org/text.asp?2016/1/1/16/194055
| Introduction|| |
Tension pneumomediastinum is a rare, life-threatening emergency. A high index of suspicion and an early computed tomography (CT) of the chest can help in diagnosing the condition in hemodynamically unstable patients. A successful treatment outcome could be achieved if the patient is attended promptly by a thoracic team with mediastinal drains and adequate Intensive Care Unit (ICU) supportive care. To the best of our knowledge, this is probably the first case report on the development of tension pneumomediastinum in an adult patient, secondary to H1N1.
| Case Report|| |
A 28-year-old woman, in her 5 th week of second pregnancy, presented with rapidly worsening breathlessness and a 4-day history of fever. On admission, she was febrile (101°F), tachypneic (28/min), and alert (Glasgow Coma Scale score 15/15), with a blood pressure of 90/60 mmHg and pulse of 120 beats/min. Oxygen saturation of 80% on room air, 92% with 10 L of oxygen via high concentration mask and extensive course left-sided inspiratory crepitations were also noted. Initial chest X-ray showed evidence of right mid and basal alveolar infiltrates with left perihilar opacity. Pneumothorax or pleural effusion was absent [Figure 1]. Laboratory investigations revealed: Hemoglobin - 13 g/dL, leukocyte count - 2200 cells/μL (neutrophils 68%), and creatinine - 0.8 mg/dL. Liver function tests showed marginally elevated enzymes, which normalized over the next few weeks. She was immediately initiated on noninvasive ventilation, intravenous fluids, oseltamivir, nebulization, and supportive management. Real-time polymerase chain reaction (RT-PCR) indicated that she was positive for H1N1.
On the 5 th and 11 th day of ICU admission, she developed right-sided and left-sided pneumothorax, respectively, and both were addressed promptly with underwater seal drains. On the 12 th day, she had a sudden respiratory arrest and became hypotensive and unresponsive. She was revived through emergency intubation and inotropic supports. Her morning chest X-ray showed pneumomediastinum [Figure 2]. An emergency CT scan also revealed extensive pneumomediastinum with cardiac compression and increased surgical emphysema of chest, paravertebral areas, anterior chest wall, posterior abdominal wall, and neck spaces [Figure 3]a and b. Emergency mediastinal (subxiphoid approach) and new bilateral pleural drains were inserted. Her blood pressure improved within a few minutes of insertion of the mediastinal drain with a drop in heart rate. Inotropes were tapered and eventually stopped after a few hours.
|Figure 2: Chest X-ray showing air streaks surrounding the heart (continuous diaphragm sign is evident)|
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|Figure 3: (a and b) Computed tomography chest showing an extensive pneumomediastinum with compression of the cardia|
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The patient's condition improved over the next few weeks. However, her hospital stay was complicated by bronchopleural fistula (conservatively managed) and multiple intercurrent infections (extended-spectrum beta-lactamases, Escherichia coli in urine, methicillin-resistant Staphylococcus aureus in central venous pressure tip, and multidrug-resistant Acinetobacter in blood), which were successfully treated prior to discharge. She was tracheostomized on the 14 th day, in view of a prolonged ventilator requirement and ICU stay. She had a spontaneous abortion in the 3 rd week of admission. She was gradually weaned off from ventilator support, although air leaks in the chest tubes persisted. Over 6 weeks of hospital stay, her clinical improvement was significant with repeat CT showing bilateral well-expanded lungs. Sequentially, the chest drains were removed and she was discharged after 2 months.
| Discussion|| |
Air in the mediastinal tissues is referred as pneumomediastinum or mediastinal emphysema. Although the condition has been recognized for more than a century, the first detailed description is credited to Hamman. The occurrence of pneumomediastinum without trauma is described as "spontaneous." The term "primary spontaneous pneumomediastinum" refers to the development of pneumomediastinum without any demonstrable predisposing disease and "secondary spontaneous pneumomediastinum" develops along with a recognizable structural abnormality, usually in the lungs or mediastinum. Thus, any of the causes of secondary spontaneous pneumothorax may also result in "secondary spontaneous pneumomediastinum." 
Pneumomediastinum, in majority of cases, is due to trauma either iatrogenic or noniatrogenic. Though the spontaneous ones are not truly spontaneous, they are usually caused by sudden raised intra-alveolar pressure due to cough, sneezing, vomiting, labor, or Valsalva maneuver. Some have been associated with the use of cocaine,  marijuana smoking,  pulmonary function testing,  and asthma.  Increased pulmonary alveolar pressure, pulmonary capillary hypotension, and alveolar wall defects are often present. Contributing factors include pneumothorax and perforation of the trachea, bronchus, or esophagus into the mediastinum.
Tension pneumomediastinum is a potentially lethal condition. Increased intra-mediastinal pressure leads to impaired central venous return through the caval system, restricted right heart diastolic filling, and collapse of the cardiac chambers, resulting in reduced stroke volume and cardiac output. Early detection is essential for prompt treatment and to improve the prognosis. Posteroanterior chest radiography should be the first radiological investigation. The classic radiological features of pneumomediastinum are streaky radiolucencies in the mediastinum, ring-around-artery sign, continuous diaphragm sign [Figure 2], Naclerio V sign, and the Earth-Heart sign (heart pressed into the shape of the globe and an increase in the transverse diameter of the heart). 
In most cases, tension pneumomediastinum is caused by traumatic rupture of the large airways or by invasive artificial ventilation techniques using volume-controlled patterns. A prompt surgical drain is essential in all the patients, and several surgical treatments have also been reported.
The generally accepted explanation for the development of pneumomediastinum is that free air may track from ruptured alveoli, along peribronchial vascular sheaths, toward the hilum of the lung. The Macklin effect, first described in 1939, highlights the following sequence of events in the development of pneumomediastinum: (1) Alveolar rupture, (2) air dissection along the bronchovascular sheath, and (3) free air reaching the mediastinum. The development of increased mediastinal pressure, in tension pneumomediastinum, might be fatal. Macklin and Macklin described this extreme variant as "malignant pneumomediastinum."  It is characterized by dyspnea, cyanosis, engorged veins in the neck, rapid low-volume pulse, and hypotension. It may mimic cardiac tamponade.
Though tension pneumothorax is reported commonly in association with traumatic pneumothorax, literature search indicates that there are no case reports on tension pneumomediastinum in relation to H1N1 pneumonia.
The present case had an acute lung injury with an acute respiratory distress syndrome, secondary to viral (H1N1-RT-PCR positive) pneumonia. She was on very high levels of positive end-expiratory pressure with bilateral pneumothorax and ICD in place, nearly 72 h prior to the development of tension pneumomediastinum. All these features suggested a preexisting alveolar injury, which could have created a Macklin effect, precipitating as "Malignant pneumomediastinum."
The patient had a slow recovery and was gradually weaned off from ventilator over a period of 6 weeks. She was discharged following no further recurrences and 10 weeks of ICU stay and is currently leading a normal life with very minimal restriction in her physical activity. Though tension pneumomediastinum could be fatal, a successful outcome can be attained through a high index of suspicion, and early detection and intervention.
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Conflicts of interest
There are no conflicts of interest.
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[Figure 1], [Figure 2], [Figure 3]