Reminder of important clinical lesson: Meckel diverticulum causing small bowel obstruction

doi:10.1136/bcr.06.2009.1970

BMJ Case Rep. 2010; 2010: bcr06.2009.1970.

Published online 2010 April 5. doi: 10.1136/bcr.06.2009.1970

PMCID: PMC3052839

Reminder of important clinical lesson

Meckel diverticulum causing small bowel obstruction

Alistair James Sharples

Princess Royal Hospital, Surgery, 48 Pooler Close, Telford, Shropshire , TF1 2HP, UK

Correspondence to Alistair James Sharples, Email: alsharples/at/yahoo.co.uk

Abstract

A 62-year-old man was admitted with generalised abdominal pain, constipation and vomiting. His abdomen was markedly distended and tender on general examination with signs of local peritonism in the left iliac fossa. He was initially diagnosed with likely acute diverticulitis and treated conservatively. A CT scan the next day showed fluid filled, dilated small bowel loops consistent with small bowel obstruction and there was a suggestion of an abscess in the left iliac fossa region. An urgent laparotomy was performed, which identified a perforated Meckel diverticulum.

Background

A Meckel diverticulum is a remnant of the vitello-intestinal duct and is thought to be present in approximately 2% of the general population.¹ It is most commonly identified coincidentally at laparotomy or laparoscopy but is estimated to cause disease in approximately 4–7% of cases.²^–⁴

Clinically, complications usually present with gastrointestinal bleeding, abdominal pain or signs of small bowel obstruction and, understandably, can often be misdiagnosed as other more common conditions. Current imaging modalities offer very little possibility of accurate pre-operative diagnosis.

Case presentation

A 62-year-old man presented complaining of colicky, generalised abdominal pain, worse in the left iliac fossa. He reported that he had not opened his bowels for 5 days and had passed no flatus. His abdomen was distended and he had vomited twice. He was anorexic but denied any associated haematemesis, fever, rectal bleeding or any change in his bowel habit prior to the onset of his current symptoms. He had an appendicectomy and right-sided open hernia repair over 40 years ago. There was no other relevant past medical history. He took no regular medication, had no allergies, drunk no alcohol and was a lifelong non-smoker.

On general examination, his temperature was 36.4°C. His pulse was regular at 90 bpm and blood pressure stable at 112/80. Respiratory rate was 12 and saturations 99% on room air. His abdomen was markedly distended and generally tender. Tenderness was most pronounced in the left iliac fossa where there was evidence of local peritonitis. Bowel sounds were normal. No masses or hernias were evident. Rectal examination revealed an empty, collapsed rectum with no masses or blood. Respiratory and cardiac examinations were unremarkable.

Investigations

Haemoglobin was 14.2 g/dl, white cell count 12.1×10⁹/l and platelets 216×10⁹/l. Sodium was low at 126 mmol/l and urea slightly raised at 8.2mmol/l. Potassium and creatinine were within the normal range. Liver function tests were unremarkable and the international normalised ratio (INR) 1.1. An abdominal x-ray (figure 1) was of poor quality but did show some distended small bowel loops. Chest x-ray (figure 2) demonstrated a distended stomach but no abnormality within the chest itself and no free air under the diaphragm.

Figure 1

Plain abdominal x-ray.

Figure 2

Plain chest x-ray.

Fluids and analgesia were administered. The patient improved clinically and passed a small quantity of stool. A preliminary diagnosis of diverticulitis was made and intravenous antibiotics commenced. A CT scan with oral contrast (figure 3) was obtained the next morning showing fluid filled, dilated small bowel loops consistent with small bowel obstruction. There were a number of matted bowel loops adherent to the anterior abdominal wall on the left side of the abdomen surrounded by gas and free fluid, suggestive of an abscess or walled off perforation. The solid abdominal organs appeared normal and there was no evidence of free air in the abdomen.

Figure 3

CT scan showed dilated small bowel loops and an area of matted bowel loops in the left iliac fossa.

Treatment

An urgent laparotomy was performed. Dilated loops of small bowel were present within the abdomen and a large abscess cavity identified in association with a perforated Meckel’s diverticulum in the left iliac fossa (figure 4). The remains of the diverticulum was removed, the small bowel decompressed and the defect closed. The peritoneal cavity was thoroughly washed out and the abdomen closed.

Figure 4

Intraoperative pictures of Meckel diverticulum prior to resection.

Outcome and follow-up

The patient recovered well post-operatively and was discharged home a week later. Histological examination of the specimen confirmed a 120 by 15 mm inflamed, perforated Meckel diverticulum.

Discussion

Meckel diverticulum is the most commonly occurring congenital malformation of the gastrointestinal tract. However it is an uncommon cause of abdominal symptoms in adults. It is estimated to cause complications in approximately 4–7% of cases²^–⁴ and of these 40% occur in children under the age of 10 years.⁵

It exists due to the persistence of the vitello-intestinal duct and is composed of all layers of the bowel. Therefore, it is a true diverticulum.⁶ Generally it is 1–12 cm in length and is found 45–90 cm from the ileocaecal valve. It is estimated to be present in approximately 2% of the population.¹

The diverticulum itself is asymptomatic but clinical manifestations arise secondary to complications. Diverticulum longer than 2 cm in males under the age of 40 years are thought to give rise to the highest number of complications.⁷

Gastrointestinal haemorrhage is the most common complication in paediatric patients, occurring most often in male patients under the age of 2 years. It can manifest anywhere along a spectrum extending from chronic episodes of haematochezia to massive acute blood loss in a shocked patient.¹

Gastrointestinal bleeding is less common amongst the adult population.⁶ In adults the most common complications seen are obstruction, inflammation and perforation.⁶^,⁷

Obstruction may be secondary to a number of mechanisms. It may be secondary to inflammation, adhesions or the diverticulum may form the lead point of an intussusception.¹^,⁸ Less frequently a tumour, arising from the diverticulum, will obstruct the bowel lumen. The diverticulum rarely can become incarcerated within a hernia.¹^,⁸ Even more uncommonly, a volvulus may develop around a persistent vitello-intestinal duct extending between the umbilicus and a Meckel diverticulum.⁹

Meckel diverticulum, like other diverticulum, are vulnerable to inflammation potentially resulting in perforation. Those diverticulum with narrow necks are particularly vulnerable as they are more prone to become obstructed by enteroliths leading to stasis within the diverticulum and consequentially inflammation.¹ Diverticulitis most commonly presents with abdominal pain, which often mimics appendicitis. A perforation will result in peritonitis.

The clinical challenge is differentiating a Meckel diverticulum from other more common conditions. As our case demonstrates, patients are often treated initially for other conditions, such as diverticulitis or appendicitis, with the correct diagnosis only being made at operation.

Plain abdominal films may demonstrate appearances typical of obstruction, perforation or may identify an enterolith but these findings are highly non-specific.¹⁰

CT is certainly of use in diagnosing small bowel obstruction. Generally, dilated small bowel loops are seen proximal to the point of obstruction with collapsed or normal bowel loops distal to the same site and CT has a high sensitivity and specificity for these signs.⁵^,¹¹ However, it is generally of little use in diagnosing a Meckel diverticulum as it is usually impossible to differentiate between the diverticulum and intestinal loops.¹²

Technetium scanning can be of use where ectopic gastric mucosa is present and angiography may be helpful in identifying bleeding originating from a Meckel diverticulum.⁵^,¹²

Learning points

Meckel diverticulum is the most commonly occurring congenital malformation of the gastrointestinal tract; however, complications are uncommon but carry a high mortality and morbidity.
Clinically, complications can present in a multitude of differing ways and often present in similar ways to other more common causes of abdominal symptoms.
CT scanning is of value in diagnosing small bowel obstruction but is very unlikely to accurately diagnose a Meckel diverticulum.
Current imaging modalities offer very little possibility of accurate pre-operative diagnosis.
The possibility of a Meckel diverticulum should not be forgotten and physicians should consider it when assessing patients presenting with gastrointestinal bleeding, abdominal pain or small bowel obstruction.

Footnotes

Competing interests: None.

Patient consent: Patient/guardian consent was obtained for publication.

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