Diaphragmatic eventration unusual presentation: a novel thoracoabdominal compartment syndrome case

Abstract

Diaphragmatic eventration is a rare entity in the adult population, and usually asymptomatic ¹ ; our case is a young man with severe right-sided diaphragmatic eventration with huge dilated colon that has compromised the right hemithorax and caused complete lung collapse and mediastinal shift similar to tension pneumothorax picture with haemodynamic alteration. A single similar case report had been published but did not shed the light on the accurate description of the pathophysiological mechanism of the disease. We believe that such a high abdominal pressure that has transmitted to the thoracic cavity due to the pliable diaphragm causing such a derangment in both the anatomy and the physiology deserves reporting and we think that the term ‘thoracoabdominal compartment syndrome’ describes it accurately, so we discuss some learning points from our case and things that could have been done better.

Background

Diaphragmatic eventration is mostly asymptomatic but the way it presented in our case is very unique, and as far as we know, it was only reported once in the literature, but never been accurately described or named.

Case presentation

A male patient in his early 20s, brought to the emergency department by the Red Crescent with a history of shortness of breath and abdominal distension. There were no family members with the patient and only brief information could be taken by phone through a distant relative that the patient been constipated and short of breath for 3 days before presentation.

The patient was drowsy, arousable to voice, tachycardic 140 beats/min, hypotensive 80/35 mm Hg, hypoxic oxygen saturation 95% on 15 L non-rebreather mask and tachypneic with a respiratory rate of 30 breaths/min.

Immediate resuscitation with 0.9% normal saline, and continued parallel examination revealed

marked decrease air entry in the right side, prominent veins in the neck, huge abdominal distension, tender all over but soft, per rectal exam: no masses.

Investigations

Acidotic pH 7.25, with high lactate 8 mg/dL.

Chest radiograph (figure 1) shows severe colonic dilatation with right-sided diaphragmatic eventration, with significant mediastinal shift and associated lung collapse and preserved diaphragm dome ruling out diaphragmatic defect, and no apparent free air, excluding pneumothorax and pneumoperitoneum.

Figure 1.

Chest X-ray showing severe colonic dilatation with right-sided diaphragmatic eventration, with significant mediastinal shift and associated lung collapse and preserved diaphragm dome indicating no diaphragmatic defect and no apparent free air.

Differential diagnosis

Diaphragmatic hernia, tension pneumothorax: the preserved diaphragm dome ruling out diaphragmatic defect, and no apparent free air, excluded pneumothorax or pneumoperitoneum.

Treatment

The patient was resuscitated with 4 L of 0.9% normal saline with no urine output, and intubated with minimal dose sedation (25 mcg fentanyl) to avoid any haemodynamic altering side effects; no inotropic support had been started; then he was taken to the operating room (OR) immediately for further resuscitation in full controlled setup and with the possibility of immediate abdominal decompression in case of any deterioration.

The patient was shifted to OR in an unstable condition with blood pressure (BP) 90/45 mm Hg and 138 beats/min; once shifted norepinephrine infusion was started. A midline laparotomy was done and a huge colon was encountered and eviscerated, and at that moment the patient arrested. Closed cardiopulmonary resuscitation (CPR) along with supraceliac blunt aortic pressure was done for 5 min, pulseless electrical activity and the patient was revived, but his BP was maintained with a high-dose inotropic support. Returning back to the abdomen the colon was iatrogenically perforated during the CPR at the level of the transverse colon, and most of it adherent to the diaphragm with the liver completely displaced to the left side (figure 2) shows the colon looks hugely distended but viable, and the rest of the bowel looks viable with no signs of ischaemia.

Figure 2.

Intraoperative picture showing the right subdiaphragmatic space, with the liver in the left side (not seen) and the transverse colon (dotted line) is completely adherent to the diaphragm with the iatrogenic injury (arrowheads) held by a Babcock. The right subcostal margin is indicated by the arrow.

Outcome and follow-up

The patient was shifted to intensive care unit, after a damage control procedure, and unfortunately was in an irreversible shock state and arrested again 5 hours after the surgery due to persistent acidosis and very low BP unable to tolerate continuous renal replacement therapy.

Discussion

Diaphragmatic eventration is a condition where the diaphragm leaf ascends abnormally high in the chest, gets thinner and the muscular part might be replaced by fibroelastic tissues; mostly it is asymptomatic and generally presents incidentally.¹ It is diagnosed mainly in the adult population, mostly on the left side, usually misdiagnosed as diaphragmatic hernia, and there are case reports of associated transposition of organs¹ as the liver in our case was not in the right but in the left and whether it was an associated situs inversus or chronic displacement we do not know. Only one similar case to ours was reported by Haldun et al ² in which abdominal pressure was high enough to cause tension within the thoracic cavity in the left side; although that case was a perforated gastric ulcer that resulted in pneumoperitoneum and Haldun described it as tension pneumothorax secondary to pneumoperitoneum, and actually did an abdominal needle decompression as well as bilateral drainage tubes in the abdomen followed by a midline laparotomy, but the patient followed the same pathway as our case and he arrested. We believe that our case is slightly different in which the colon was intact until it was iatrogenically injured, and the term thoracoabdominal compartment syndrome is more descriptive and accurate for both cases; as the pleural cavity did not contain any air on X-rays and the lung collapsed as a result of the transdiaphragmatic pressure from the abdominal cavity and the weak pliable diaphragm. Although we did not measure the abdominal pressure in our case due to the emergent nature of the situation, we believe that it was abnormally high since it was able to shift the mediastinum. Abdominal compartment syndrome (ACS)³ is a well-known entity in medicine, and the respiratory embarrassment with ventilation difficulty and raising peak pressure is part of the definition of ACS, but to reach to the extent of unilateral mediastinal shift and total lung collapse (due to the diaphragmatic eventration) is what makes our case worthy of reporting and describing it as a new syndrome in medicine.

Learning points.

• Using medications like ketamine to sedate the patient for intubation might be a better choice than fentanyl.

• Shifting an unstable (not bleeding) patient to the operating room is almost obsolete in modern medicine, but the unicity of this case and the urgent need of abdominal decompression and the inability to do it in the emergency department forced us to shift the patient, although we could have started an inotropic agent to augment the blood pressure.

• Higher volumes of crystalloids/colloid resuscitation before decompressing the abdomen might have prevented the significant drop of preload when the abdomen was opened, which we think is the cause of the arrest.

• Better surgeon/anaesthetist communication might have led to better results.

• Diaphragmatic eventration is a disease of varying severity, and this paper along with previous case reports and series could open the door to a new classification for diaphragmatic eventration in adults.^{4 5}

• Diaphragmatic eventration is a disease which the diaphragm fails to act as muscle barrier, and in the advanced stage it simply becomes like a membrane that fails to maintain any pressure gradient between the two cavities. In other words, anatomically there are two cavities, but physiologically there is only one cavity (thoracoabdominal cavity), and any rise in pressure in either cavity will equilibrate to the other, leading to thoracoabdominal compartment syndrome.