Tension gastrothorax in a child, a diagnostic dilemma

A 12-year-old child presents with sudden onset of shortness of breath and pain in left upper quadrant of abdomen for 6 hours duration. The child had past history of minor trauma 1 year back. On physical examination, the child was tachypneic with decreased air entry on left chest. Then, further investigations were advised after discussion with radiologists on-call.

On AP CT Scout view, large air-filled cavity was seen almost occupying the left hemithorax. Left diaphragm is not visible (Figure 1a). Chest CT showed distended stomach causing passive atelectasis of the left lung (Figure 1b, 2a, 2b, 2c). The stomach was seen herniating through the oesophageal hiatus into the left hemithorax and distended with trapped air (Figure 2b, 2c). On CT with oral contrast, the swallowed contrast was seen within the herniated part of stomach and pylorus in coronal images and in the dependent aspect of the distended stomach with air-contrast level (Figure 3a, 3b).

Tension gastrothorax is a rare and emergent condition a child can present in emergency department. It is always associated with diaphragmatic hernia. Left side is more commonly affected than the right one, the liver making up for the right hemidiaphragm. Diaphragmatic hernia can be either congenital or acquired. Congenital diaphragmatic hernia (CDH) occurs in 1 in 2500-4000 live births. The majority are detected antenatally or during early neonatal period. Acquired hernia can be traumatic due to diaphragmatic rupture or the herniation of the abdominal content through the enlarged natural hiatuses due to acute or gradual increased abdominal pressure in emergency setting or in delayed presentation respectively. In our case, remote trauma is believed to be the causing event for hernia. The most common organs involved are stomach and colon. The incidence of traumatic diaphragmatic rupture is approximately 2-4% of the paediatric trauma and approximately 30% of diaphragmatic hernias present lately. The incidence of late presentation CHD is approximately 2.6%-45%. However, incidence of tension gastrothorax is not well reported. [1,2,3].

On Chest X-Ray, large air-filled cavity is seen almost occupying the hemithorax with or without air-fluid level if the stomach is largely distended with trapped air due to one way valve mechanism created due to collapsed pylorus and kinking of the gatro-oesophagal junction. The outline of the involved side of diaphragm is not seen clearly. Gastric bubble is absent if hernia is located on the left side. It is difficult to differentiate diaphragmatic hernia from tension pneumothorax from chest X-Ray only. Both are life-threatening conditions. Further, erroneous diagnosis of tension pneumothorax could lead to unadapted treatment. Therefore, further imaging with Contrast-enhanced  Computed Tomography (CECT) chest is usually done with or without oral contrast for definitive diagnosis. On CECT chest, exact identification of herniated contents along with analysing the position of abdominal vessels and status of vascularity of gastric wall can be evaluated. The distended stomach causes apical displacement as well as compressive atelectasis of the ipsilateral lung field. Oral contrast can be seen within the distended stomach [4,5].

Tension gastrothorax is a rare and emergent condition in a child with good prognosis if managed properly in acute settings. In case of massive distension of the stomach and mediastinal shift, cardiac arrest and sudden death can occur at any moment. Our case was managed with Naso-gastric tube (NGT) decompression followed by emergency laparotomy and reduction of the herniated stomach followed by diaphragmatic defect repair.

In summary, differentiating tension gastrothorax from pneumothorax is the first step of patients' management involving adapted imaging. Then, NGT can be placed to decompress the stomach before operating on the patient. If NGT is unsuccessful, then attempt transthoracic needle decompression of the stomach and go for emergency laparotomy with reduction of the herniated contents into the abdomen and closure of the diaphragmatic defect [4].