Case 1: A child with gastrointestinal bleeding

A previously healthy seven-year-old boy presented to the emergency room with a two-day history of abdominal pain and bloody stools. His pain was crampy and intermittent, and was isolated to the left side of his abdomen. His parents described bright red blood and passing of clots per rectum, in addition to episodes of melena.

The patient had been afebrile, had no sick contacts, no significant travel history and no previous history of gastrointestinal bleeding. His appetite remained good. The family history was unremarkable for coagulopathies, inflammatory bowel disease or polyps.

On admission, he was well hydrated, pale but nontoxic. His highest temperature was 38.1°C. He demonstrated an orthostatic heart rate increase from 120 beats/min to 140 beats/min, and a resting blood pressure of 102/42 mmHg. His cardiovascular examination revealed a grade II/VI systolic ejection murmur and normal capillary refill. He had a soft, nondistended abdomen with pain on palpation of the left abdominal quadrants. No peritoneal signs were present.

Two days earlier, at the onset of symptoms, the patient’s hemoglobin level was measured at 119 g/L, dropping to 83 g/L the following day. At presentation, his hemoglobin level was 56 g/L. Electrolytes, renal and liver function tests, white blood cell count, international normalized ratio and partial thromboplastin time were all normal.

The patient received a fluid bolus and a packed red blood cell transfusion. Stool was sent for culture, electron microscopy, and ova and parasites. An abdominal ultrasound demonstrated no evidence of intussusception. An additional investigation revealed the diagnosis.

CASE 1 DIAGNOSIS: MECKEL’S DIVERTICULUM

A nuclear medicine Meckel’s scan was completed. Evidence of ectopic gastric mucosa was found in the right lower quadrant adjacent to the bladder, typical for a Meckel’s diverticulum. Six days later, the patient underwent laparoscopic excision of the Meckel’s diverticulum without complication, and was symptom-free at outpatient follow-up.

Rectal bleeding leading to hemodynamic changes in children is uncommon. Common causes of a lower intestinal bleed include anal fissures, intussusception, infectious enterocolitis, Meckel’s diverticulum and juvenile polyps. A more elaborate differential would include rectal trauma, vascular malformations, intestinal duplication, Henoch-Schönlein purpura, hemorrhoids and varices. In older children, one must think of inflammatory bowel disease, while in infants, necrotizing enterocolitis and milk protein intolerance should be considered.

A Meckel’s diverticulum, named for Johann Friedrich Meckel (1781-1833), is the most common congenital anomaly of the small intestine. Based on autopsy studies, Meckel’s diverticulum occurs in 1% to 3% of the population, although more than 95% of cases remain asymptomatic. Most are located at a variable distance proximal to the ileocecal valve and range in length from 1 cm to 5 cm. Approximately 50% of complications associated with a Meckel’s diverticulum occur in patients younger than 18 years of age.

Early in intrauterine life, the omphalomesenteric duct connects the developing gut with the yolk sac. Normally, this structure is completely obliterated at approximately six to eight weeks’ gestation, but if this separation is incomplete it can lead to the development of a fistula, cyst, ligament or, most often, a diverticulum. The cause for failure of the duct to disappear is unknown. Because it is a true diverticulum, it contains all the layers of the intestinal wall. It is located on the antimesenteric border and its blood supply arises from a remnant of the right vitelline artery. Ectopic gastric mucosa is found in 50% to 62% of symptomatic Meckel’s diverticuli, and in 95% to 100% of patients whose Meckel’s diverticuli present with rectal bleeding.

In the present case, the patient reported rectal bleeding and intermittent crampy abdominal pain. Interestingly, painless rectal bleeding is the leading clinical manifestation reported in children, occurring in approximately 31% to 34% of symptomatic Meckel’s diverticuli. Hemorrhage typically results from acid secretion, which causes peptic ulceration at the junction of ectopic gastric mucosa and normal ileal mucosa. Other clinical presentations include small bowel obstruction in 2% to 31% of symptomatic diverticuli, and inflammatory-related symptoms that may mimic appendicitis in 16% to 21%. In adults, neoplastic findings have also been reported, and include benign mesenchymal tumours, adenocarcinomas, sarcomas and carcinoid tumours.

Confirmation of a Meckel’s diverticulum can be difficult because standard abdominal radiography and barium studies are not helpful. Diagnosis is made with a ^99mtechnetium pertechnetate scintigraphic study, a noninvasive investigation that is often called a Meckel’s scan. ^99mTechnetium pertechnetate, a radionucleotide, loosely binds plasma protein and accumulates in functional gastric mucosa. The Meckel’s diverticulum is identified on the scan by a focus of increased activity, often mid-abdomen or in the right lower quadrant. False-positive images can result from ureteral obstruction, intussusception, sacral meningomyelocele, arteriovenous malformation, hemangiomas and other inflammatory masses, while false-negative scans are usually the result of lack of ectopic gastric mucosa within the diverticulum. Minimization of false-negative Meckel’s scans has been accomplished by pretreating the patient with an H₂-receptor antagonist, such as ranitidine.

In the present case, a seven-year-old boy presented repeatedly to emergency rooms with progressive, painful rectal bleeding. Although not the typical presentation, it is in keeping with documented cases of symptomatic Meckel’s diverticuli. The present case also demonstrates that a gastrointestinal bleed in children can lead to significant blood loss with hypovolemia requiring transfusion.

CLINICAL PEARLS

• Meckel’s diverticulum occurs in over 1% of the population; more than one-half of symptomatic cases present in patients younger than 18 years of age.

• Although the hallmark of a Meckel’s diverticulum is painless rectal bleeding, other symptoms may predominate. Bowel obstruction, appendicitis-like symptoms or an acute abdomen with bleeding may represent a symptomatic Meckel’s diverticulum.

• A gastrointestinal bleed should not be considered a benign condition, particularly when accompanied by symptoms of hypovolemia.