Gastrointestinal bleeding — branching viva

Opening — framing the problem

The examiner begins: an 18-month-old boy passes a large amount of bright red blood per rectum with no pain and looks well. What is your first framework for thinking about this? [1]

My first framework is the upper versus lower split at the ligament of Treitz and the age of the child. Bright red blood per rectum usually means a lower tract source, and in a well toddler with no pain a Meckel diverticulum and a juvenile polyp head the differential, with an anal fissure excluded by the perianal exam. I would first confirm he is haemodynamically stable, because even a painless bleed can be large. [1] [3]

Branch A — the Meckel diverticulum

Why does a painless bleed in a toddler point specifically to a Meckel diverticulum, and what is the rule of twos? [4]

A Meckel diverticulum is a remnant of the vitelline duct on the anti-mesenteric border of the ileum, and when it contains ectopic gastric mucosa that mucosa secretes acid, ulcerates the adjacent ileum and bleeds painlessly. The rule of twos is that it occurs in about two per cent of the population, sits two feet from the ileocaecal valve, is two inches long, usually presents before age two, and contains two common ectopic tissue types, gastric and pancreatic. [4] [3]

Branch B — the investigation

How do you confirm a bleeding Meckel diverticulum, and what if that test is negative? [4]

The investigation of choice is the technetium-99m pertechnetate Meckel scan, which detects the ectopic gastric mucosa. If the scan is negative but suspicion remains, high-frequency ultrasound may identify the diverticulum, and capsule endoscopy or a tagged red cell study can localise an obscure small bowel source. The definitive treatment is surgical resection of the diverticulum and the affected ileal segment. [4] [2]

Branch C — the infant with colic

Now a different child: a 9-month-old with episodic drawing-up colic, vomiting and bloody stool, and a sausage mass in the right upper quadrant. What is this, and what do you do? [6]

This is intussusception, where one segment of bowel telescopes into the next, and the currant-jelly stool reflects venous congestion and ischaemia, so it is a late sign. I would assess and resuscitate, then arrange an abdominal ultrasound looking for the target or donut sign. The first-line treatment in a stable child is ultrasound-guided pneumatic or hydrostatic enema reduction, moving to surgery if reduction fails, or if there is perforation or peritonitis. [6] [2]

Branch D — the child who vomits blood

Finally, a child with known chronic liver disease vomits bright red blood. How does your management change? [5]

I presume variceal haemorrhage from portal hypertension. I resuscitate with two large-bore cannulae and crystalloid, move to blood products early, and start an octreotide infusion to reduce portal flow and an intravenous proton-pump inhibitor, with prophylactic antibiotics because she is cirrhotic. I arrange urgent endoscopy for band ligation, with balloon tamponade as a temporary bridge if bleeding is uncontrolled and a shunt or surgery for refractory cases. [5] [2]

Closing — the safety rule

Give me the single rule you want every junior to hold about gastrointestinal bleeding in children. [1]

Assess the circulation first, because a child's blood pressure holds until late, so resuscitate the tachycardic child with crystalloid and blood before chasing the diagnosis, then localise the bleed by its colour and the child's age, and escalate to endoscopy, radiology or surgery for the severe or refractory case. [1] [2]