Robert is a 14-year-old boy who re-presents to ED with a history of rectal bleeding. He has had four or five episodes of passing bright, red blood PR over the last three days, having been a previously well child. He has also had four or five episodes of non-bilious vomiting.
Mum has noticed that he has now become pale and lethargic.
On his first presentation to ED, two days prior, the working diagnosis was bacterial gastroenteritis. His haemoglobin at that time was 99g/L. It has fallen to 45g/L on this presentation.
On examination, he is very pale, his heart rate is 120, and his blood pressure 95/65.
What are your differentials at this point?
- Bacterial: Campylobacter, Salmonella, Shigella, E. coli, Yersinia, C. difficile
- Viral: rotavirus, COVID-19
- Inflammatory bowel disease
- Henoch Schonlein Purpura
- Hereditary haemorrhagic telangiectasia
- Bleeding polyp
- AV malformation
- Meckel’s diverticulum
- Anal fissure
What investigations would you perform?
- Bloods: FBC, U+E, LFTs, CRP, ESR, VBG, blood culture, coagulation screen
- Stool culture, stool for C.difficile
- Covid swab
- Abdominal ultrasound
- CT abdomen/pelvis
- Meckel’s scan
What is Meckel’s Diverticulum?
You may remember “The Rule of Two’s” from medical school.
MD is a congenital abnormality of the small intestine that is present in 2% of the population. 2% of these people will become symptomatic. It is 2 inches long and 2 feet from the ileocoecal valve. There can be 2 types of ectopic tissue: gastric or pancreatic. There is a 2:1 male preponderance.1,2,3
MD comprises the three layers of the intestinal wall and is, therefore, a true diverticulum.3 It results from the incomplete obliteration of the omphalomesenteric duct. The omphalomesenteric duct connects the yolk sac to the intestinal tract during early foetal life and is usually obliterated by the seventh week of gestation. Failure to regress can result in a spectrum of abnormalities, including: MD, patent vitelline duct, fibrous band, sinus tract, umbilical polyp and umbilical cyst.3
What happens to the symptomatic 2%?
The presentation of MD is highly variable. It is best to consider the different presentations based on the underlying anatomical or pathological processes the diverticulum can undergo.
1. It gets in the way
The abnormal anatomy in MD can lead to intestinal obstruction. In children, this usually presents as intussusception or volvulus.3
The diverticulum acts as the lead point in intussusception. These patients present with abdominal pain. The symptoms can be non-specific, particularly in pre-verbal children. They are “off form”, or parents complain about poor feeding, constipation, abdominal distension. As you can see from Robert’s case, intussusception can also lead to massive GI haemorrhage.
Volvulus of the intestine may occur around the fibrous cord that connects the Meckel’s to the umbilicus.4
2. The ectopic gastric tissue can cause an ulcer
The ectopic gastric mucosa in the diverticulum can secrete acid which results in ulceration of the small bowel. This usually presents as painless bleeding, which can be massive in nature.3 It may also present due to anaemia from chronic bleeding. The bleeding is usually dark red or maroon in colour.3 Robert’s Technitium-99m scan (or Meckel’s scan) was positive, suggesting the presence of gastric mucosa, so he may have intussusception plus ulceration, both leading to his massive GI haemorrhage.
3. It gets angry
As the Meckel’s is a blind ending diverticulum, it can undergo a process of inflammation, similar to appendicitis. Obstruction at the base of the diverticulum leads to bacterial overgrowth and inflammation. This can present with fever, vomiting and abdominal pain, which is often indistinguishable from acute appendicitis. The MD may also perforate, leading to diffuse peritonitis and a very unwell patient.
As these symptoms are all non-specific, it is important to think of MD as a diagnosis in children presenting with any of the symptoms above.
How is it diagnosed?
MD requires a high index of clinical suspicion to aid diagnosis. Most imaging modalities are non-specific but can still be helpful. X-ray or ultrasound may show a small bowel obstruction and intussusception.5 Finding a normal appendix on ultrasound, may lead to careful consideration of MD as an alternate cause.
A Meckel’s scan may be performed. This is a nuclear medicine scan using Technitium-99m, which accumulates in the ectopic gastric mucosa (see Image 2).5 The test is reliant on the presence of gastric mucosa, which is only present in 4.6-71% of symptomatic MD.5 Premedication with H2 antagonists may increase the accuracy of the scan.5
MD is often only confirmed on exploratory laparoscopy or laparotomy.
How is it treated?
Definitive treatment is surgical resection of the diverticulum, either laparoscopically or by laparotomy. Simple diverticulectomy and closure of the ileum is acceptable except in cases of GI bleeding where the ulcer may extend to the adjacent ileum, in which case segmental resection with re-anastomosis of the small bowel should be carried out.4
Robert’s haemoglobin is 45. He requires multiple transfusions with packed red cells, FFP and fibrinogen. He is stabilized and transferred to PICU.
He has an emergency OGD and colonoscopy. They do not reveal the source of bleeding. His abdominal ultrasound shows a small bowel intussusception, suspicious for Meckel’s diverticulum (MD). He has a Meckel’s scan which confirms MD. He undergoes surgical resection of the diverticulum and recovers well.
Who was Meckel?
Johann Friedrich Meckel (the younger) was a German anatomist whose principle interest was the study of congenital malformation and the developmental aspects of the lungs and bloods vessels.6
Interestingly, MD was first described by Wilhelm Fabricius Hildanus, a German Surgeon, in 1598.7 It wasn’t named, however, until Meckel reported his research on the diverticulum’s anatomy and embryology in 1809.
He is also responsible for the medical eponyms Meckel cartilage and Meckel syndrome.
He is called Johann Friedrich Meckel The Younger because his grandfather was called by the same name and was also an anatomist, as were his father, younger brother and son.
You can find out more about him and the Meckel anatomist dynast on LITFL.
References for Much Ado about Meckel’s
1. Meckel’s Diverticulum [Internet]. [cited 2021 Apr 1]. Available from: https://pedemmorsels.com/meckels-diverticulum/
2. Rule of 2s in Meckel diverticulum | Radiology Reference Article | Radiopaedia.org [Internet]. [cited 2021 Apr 1]. Available from: https://radiopaedia.org/articles/rule-of-2s-in-meckel-diverticulum-1
3. Keese D, Rolle U, Gfroerer S, Fiegel H. Symptomatic Meckel’s Diverticulum in Pediatric Patients—Case Reports and Systematic Review of the Literature. Front Pediatr [Internet]. 2019 Jun 26 [cited 2021 Apr 12];7(JUN):267. Available from: https://www.frontiersin.org/article/10.3389/fped.2019.00267/full
4. Ivatury RR. Meckel’s diverticulum and the eponymous legend. Vol. 87, Journal of Trauma and Acute Care Surgery. Lippincott Williams and Wilkins; 2019. p. 451–5.
5. Hansen C-C, Søreide K. Systematic review of epidemiology, presentation, and management of Meckel’s diverticulum in the 21st century. Medicine (Baltimore) [Internet]. 2018 Aug 1 [cited 2021 Apr 12];97(35):e12154. Available from: https://journals.lww.com/00005792-201808310-00091
6. Johann Friedrich Meckel The Younger • LITFL • Medical Eponym Library [Internet]. [cited 2021 Apr 12]. Available from: https://litfl.com/johann-friedrich-meckel-the-younger/