Immunocompromised Toddler With New Onset Abdominal Pain

A 21-month-old girl with a left frontal temporal atypical teratoid/rhabdoid tumor (WHO grade IV) status post debulking of the tumor, presented with acute onset of abdominal pain and fussiness. In addition to the abdominal pain, acute intolerance of gastric tube feedings, with vomiting and bloody diarrhea, developed. The day before presentation, she had a low-grade fever, with a maximum temperature of 38.2°C (100.8°F). All culture results to date had been negative. For the past 3 days postchemotherapy, she had been receiving filgrastim (granulocyte colony-stimulating factor).

On physical examination, the patient was in moderate distress secondary to pain. She had obvious abdominal distension and pain on palpation of the right side more than the left. The abdomen was soft with active bowel sounds. The gastric tube site appeared clean and dry, without erythema or drainage. Heart sounds were regular without murmurs. Pulses were good, with a capillary refill approximately 3 seconds. Respirations were unlabored, and lungs were clear to auscultation.

Laboratory results showed a white blood cell count of less than 100/µL, hemoglobin level of 8.2 g/dL, hematocrit of 23.5%, platelet count of 114,000/µL, and mean corpuscular volume of 81.9 fL. Capillary blood gases: pH, 7.30; Pco2, 41.5 mm Hg; Po2, 49 mm Hg; and Hco3, 19.9 mEq/L. The serum lactate level was 1.5 mg/dL.
Abdominal imaging studies confirmed the diagnosis.

How do you read this image?

A. Acute appendicitis.
B. Neutropenic enterocolitis.
C. Bacterial ileocecitis.
D. Pseudomembranous enterocolitis.

(Answer and discussion begins on next page.)

Answer: B, neutropenic enterocolitis

The radiograph showed an unusual pattern of lucency along the ascending colon (Figure 1). Gastric tube feedings were discontinued, and intravenous therapy with cefepime, tobramycin, and metronidazole was started for suspected neutropenic enterocolitis (NE). Abdominal CT scans showed extensive pneumatosis extending from the terminal ileum through the distal transverse colon (Figures 2 and 3). There were scattered foci of free intraperitoneal air.

NE, also known as typhlitis (from typhlon, the Greek word for cecum) and ileocecal syndrome, is defined by the triad of neutropenia, abdominal pain, and fever. It is also characterized by bloody stool and an aggressive course. The incidence of NE based on retrospective clinical studies varies from 1.8% to 32.5%, with the highest incidence in pediatric patients.1

NE most commonly occurs after a patient receives chemotherapy for solid or hematologic malignancies; however, it has also been described in other neutropenic or immunosuppressed settings, such as aplastic anemia, congenital cyclic neutropenia, AIDS, and after bone marrow or organ transplant.2-4 The pathogenesis is poorly understood but is thought to be due to mucosal injury, often caused by chemotherapy and leukemic infiltration.2 The mucosal injury leads to a necrotizing inflammatory process and intramural colonic infection. The inflammation and necrosis can lead to perforation of the gut wall and systemic dissemination of the infection.1,5
Definitive diagnosis of NE requires tissue confirmation, although it is not commonly done.2 Imaging studies are important for diagnosis because the clinical manifestations of NE are nonspecific. A plain radiograph usually shows a paucity of gas in the right side of the abdomen.6 CT and ultrasound imaging have been reported to be more sensitive and specific than plain films and are the imaging modalities of choice for the diagnosis of NE.7 CT findings may show bowel wall thickening, right lower quadrant inflammatory mass, fluid-filled and dilated cecum, pericecal fluid, and inflammatory changes in pericecal soft tissues; ultrasound findings show echogenic thickening of the colonic mucosa.7

Acute appendicitis can present similarly to NE, with fever and abdominal pain. Other conditions that mimic NE include acute or chronic inflammatory diseases of the ileocecal area and the right colon, such as cytomegalovirus infection and bacterial ileocecitis, and pseudomembranous enterocolitis.6 Viral titers can be checked to help make a diagnosis. Endoscopy is usually contraindicated due to pancytopenia.

Complications include sepsis, postoperative bleeding, and risk for coagulopathy. NE is considered a life-threatening complication of neutropenia resulting from oncologic and other etiologies; the associated mortality rate is 29.5% to 50%.1,5 Studies to further understand the pathogenesis of NE as well as to find ways to prevent and reliably diagnose it (with techniques such as high-resolution ultrasound imaging) are ongoing.

Treatment of NE is individualized according to disease severity and stability of the patient. Successful outcomes have been described with both medical management and surgical intervention. Treatment with bowel rest, intravenous fluids, and broad-spectrum antibiotics is preferred when there are no peritoneal signs. Surgery is required in patients with transmural necrosis, perforation, or clinical deterioration despite medical management.2

Our patient was considered high risk for surgery, given her neutropenia, mild thrombocytopenia, and recent chemotherapy. She was treated with broad-spectrum antibiotics and bowel rest for 14 days, with close monitoring for intestinal perforation. She improved slowly and gastric tube feedings were restarted.