Unexpected internal hernia in a patient with small bowel obstruction: an old surgical axiom

Abstract

An 85-year-old man with no previous laparotomies and no herniae presented with a small bowel obstruction. CT imaging did not suggest any obvious cause; however, a transition point at the terminal ileum was noted. At laparotomy, the small bowel was unexpectedly found to be obstructed through a tight anterior hiatal defect. No resection was required and the defect was closed. On retrospective review of the CT images, the herniated small bowel can clearly be seen anterior to the oesophagus and can also be appreciated as a retrocardiac air–fluid level on chest X-ray (initially felt to be a small type I hiatal hernia). Our case highlights the surgical axiom that in patients with small bowel obstruction with no scars and no herniae consideration should be given to an unusual or sinister cause.

Background

Small bowel obstruction is a common acute surgical presentation with the majority of cases resulting from adhesions (even in the virgin abdomen¹), followed by herniae (which can be internal or external) and malignancy.² Adhesions are most commonly related to previous surgery, however can also be congenital or secondary to previous inflammation. Rarer causes of small bowel obstruction include intussusception, volvulus, Crohn’s disease, tuberculosis and gallstone ileus.

Case presentation

A relatively fit, independent 85-year-old man presented acutely with 5 days of colicky central abdominal pain and vomiting. He also described no passage of stool for 5 days and no flatus for 1 day. Previous medical history included suture repair of a left inguinal hernia around 40 years prior, right hip osteoarthritis for which he was on regular co-codamol and ophthalmic shingles 5 years prior.

Physical examination revealed a slim patient with visible and palpable distended small bowel loops. The abdomen was otherwise soft and non-peritonitic with only mild tenderness. Apart from a left groin crease incision from the left inguinal hernia repair, there were no other scars, and no herniae were noted.

Investigations

Initial bloods suggested fluid depletion with urea 21.6 mmol/L and estimated glomerular filtration rate 57 mL/min/1.73 m². Inflammatory markers were mildly raised with white cell count 10.0×10⁹/L and C-reactive protein 50 mg/L. Lactate was normal. Chest X-ray revealed a retrocardiac air–fluid level felt to be a longstanding asymptomatic sliding hiatus hernia and a small area of linear atelectasis in the right mid zone. Abdominal X-ray revealed a stepladder appearance characteristic of small bowel obstruction with small bowel loops distended to 6 cm and no gas in the large bowel.

Contrast CT imaging on day 1 of admission revealed dilatation of the jejunum and ileum to a transition point in the terminal ileum. There was no evidence of mural thickening or malignancy. A right inguinal hernia was noted containing the fundus of the bladder and the appendix, but no bowel.

Treatment

Initial management consisted of nasogastric (NG) tube decompression, nil oral intake and intravenous fluids with urinary catheterisation and careful monitoring of fluid balance. Repeat physical examination on day 1 of admission once again revealed a distended but soft and non-peritonitic abdomen in a physiologically stable patient. Initial working diagnosis was of a small bowel obstruction of unknown cause.

By day 2 of admission, there had been no clinical improvement with ongoing abdominal distension, no passage of flatus and high NG tube aspirates. Water-soluble oral contrast was not considered as an adhesional cause was felt unlikely. A decision was made for laparotomy the same day. The initial finding on opening the peritoneal cavity was of a flimsy band adhesion between the lower omentum and the left iliac fossa parietal peritoneum. Although this was not involving the distended small bowel loops it was divided (the relevance of this is discussed later).

The distended small bowel was then traced from the ileocaecal valve for around 60 cm, where it was found to be entering a 2.5 cm defect situated anterior to the oesophagus. There was no hernia sac associated with this defect, and the small bowel was released which was mildly dusky but otherwise healthy. Small bowel content was milked proximally and aspirated via the NG tube. A decision was made to close the hiatal defect which was done with a non-absorbable suture.

Further inspection of the herniated small bowel was satisfactory and resection was not required. The abdomen was closed and the patient returned to the ward with ongoing NG drainage and nil oral intake.

Outcome and follow-up

Diet was reintroduced on the second postoperative day that was tolerated well. Renal function quickly normalised. Discharge was unfortunately delayed to the 10th postoperative day due to requirements for physiotherapy and a short period of rehabilitation. At follow-up, 11 weeks postoperatively, his gastrointestinal function was normal. His wound had healed well and he had returned to his baseline level of function and independence.

Discussion

Our case highlights the surgical axiom that in patients with small bowel obstruction with no scars and no herniae consideration should be given to an unusual or sinister (ie, malignant) cause. It should be noted, however, that the most common cause of small bowel obstruction in the virgin abdomen is still adhesions.¹

The ‘unusual cause’ in this patient was a hiatal defect anterior to the oesophagus through which the small bowel herniated. The incidence of hiatal herniae in the general population is approximately 0.5%; however, the majority of these are small sliding herniae (around 95%).³ Paraoesophageal herniae form the minority and are usually found to contain a combination of other organs such as stomach, omentum or transverse colon.

A paraoesophageal hernia containing only small bowel is, therefore, rare and on the literature review, the authors were only able to find similar cases of small bowel obstruction in patients with large, complex paraoesophageal herniae containing multiple structures, or patients who recently had upper GI surgery (eg, transhiatal oesophagectomy). Of note, it was felt that the hernia in this case was unlikely to have been present before the acute event due to the absence of any GI symptoms in the past. However, a hiatal defect was likely present for a long period of time, possibly related to generally weak connective tissues as evidenced by the previous left inguinal hernia 40 years ago.

The herniation of small bowel through this pre-existing hiatal defect with narrow boundaries, therefore, caused the small bowel obstruction. Interestingly this may have been precipitated by the band adhesion between the omentum and left iliac fossa pushing the small bowel to the supracolic compartment from the infracolic compartment in which it usually resides.

Of further interest is the radiological aspect of this case. The CT scan suggested a transition point in the terminal ileum. This is contradictory to the laparotomy findings, and on retrospective review of the CT images, the herniated small bowel is clearly seen at the diaphragmatic hiatus (figure 1), suggesting the initial CT report was incorrect. Also on review of the admission chest X-ray, the retrocardiac air–fluid felt to be a longstanding type I hiatal hernia can now be appreciated as the cause of the small bowel obstruction. Of note, chest X-ray repeated 8 weeks postoperatively for follow-up of the linear atelectasis showed resolution of the air–fluid level (figure 2).

Figure 1.

Contrast CT demonstrating the paraoesophageal hernia.

Figure 2.

Serial chest X-rays demonstrating resolution of the paraoesophageal hernia.

Patient’s perspective.

From the minute I came into hospital until coming to the clinic for follow-up I have had absolutely no complaints. When I arrived to hospital, I was seen almost immediately. After the CT scan, the consultant explained I had a blockage in my bowel and needed emergency surgery. I did not have much time to think about it, as I was more worried about my wife being home on her own. After the surgery, I managed okay and everyone in the hospital treated me very well. I am back to driving now and have family close by who are all very supportive.

Learning points.

• We demonstrate a rare cause of small bowel obstruction, with no similar cases found in the literature.

• The value of personally reviewing CT images prior to operating should not be understated, particularly in a patient with no previous abdominal surgery.

• This case highlights the surgical axiom that in patients with a small bowel obstruction with no scars and no herniae consideration should be given to an unusual or sinister cause