neutropenic enterocolitis

School ager

status with acute lymphocytic leukemia and abdominal pain. AXR AP (above left) is unremarkable. Axial CT with contrast of the abdomen (above right) shows moderate thickening of the cecum. Transverse and sagittal US of the cecum (below) shows a moderately thickened cecum lying above the right psoas muscle.The diagnosis was typhlitis in a patient with acute lymphocytic leukemia.

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School ager

with acute lymphoblastic leukemia and abdominal pain. Axial CT with IV and oral contrast of the abdomen shows marked thickening of the wall of the cecum. The remainder of the colon was unremarkable.The diagnosis was typhlitis in a patient with acute lymphoblastic leukemia.

pediatricimaging.org • CC-by-nc-sa 4.0

Radiopaedia • CC-by-nc-sa 3.0 • de

Typhlitis, also called cecitis or neutropenic colitis, is a necrotizing inflammatory condition which typically involves the cecum and, sometimes, can extend into the ascending colon, appendix or terminal ileum.

Epidemiology

Typhlitis was first described in children with leukemia and severe neutropenia (seen with an absolute neutrophil count < 1000 per microliter). It most commonly occurs in immunocompromised patients, chemotherapy and steroid therapy patients including:

leukemia (most common)
lymphoma
aplastic anemia
AIDS
solid organ transplant

Clinical presentation

Clinically, patients with typhlitis present with a mixture of localized and systemic symptoms including a fever, chills, nausea, vomiting, diarrhea, abdominal pain, tenderness and a distended abdomen. Peritoneal irritation and occult bloody stools may be present. Pain in the right lower quadrant may mimic appendicitis.

Pathology

The condition is characterized by intramural bacterial invasion without an inflammatory reaction. This then leads to edematous thickening and induration of the cecal wall or other mural segments of the colon and distal small bowel.

The exact cause is unknown but is believed due to a combination of ischemia, infection (especially with cytomegalovirus, Pseudomonas aeruginosa), mucosal hemorrhage, and perhaps neoplastic infiltration .

Radiographic features

Plain radiograph

Plain film findings are often non-specific. May show evidence of a small bowel obstruction (SBO), soft-tissue mass in the right lower quadrant, thumbprinting due to bowel wall edema intramural gas or bowel wall thickening.

Ultrasound

Transabdominal ultrasonography demonstrating bowel wall thickening in an appropriate clinical context has been used to supplement the clinical diagnosis of typhlitis. Bowel wall thickening may be eccentric or concentric and is often dramatic; cecal wall measurements are often above 1 cm in severe cases. Sonographic findings are relatively non-specific, but are especially helpful in high pretest probability patients, and may also address the possibility of cholecystitis which, especially in the immunocompromised, have an atypical presentation .

Bowel wall thickening >4 mm is virtually always demonstrated; other features consistent with the diagnosis include:

preferential involvement of terminal ileum, cecum, and ascending colon
- involved segments often demonstrate luminal distension with hypoechoic fluid
- increased echogenicity of peri-cecal fat
localized hypokinesis/akinesis of involved bowel loops, with otherwise preserved motility
hypoechogenicity of the thickened bowel wall
- haustral folds in involved colonic segments are usually preserved
- color flow interrogation of involved bowel demonstrates preservation of bowel wall perfusion
- characteristic echogenic thickening of the mucosa has been reported in some pediatric reports

Computed tomography should always supplement sonographic evaluation of typhlitis, especially for occult complications including intra-abdominal abscess and bowel perforation.

CT

This is often the imaging modality of choice in patients suspected of having typhlitis in view of high risks of perforation during colonoscopy or during a barium enema .

CT may demonstrate thickening of the cecum as well as fat stranding, pneumatosis intestinalis, bowel wall thickening and ileus. Features of small bowel obstruction may also be seen. There may be intramural areas of low attenuation which may represent hemorrhage or edema .

Serial CT may also play a role in monitoring the success of treatment .

Angiography (DSA)

Arteriography is not part of the routine assessment. The entire cecum may be hypervascular, which may be seen as intense staining of the mucosa and its folds .

Treatment and prognosis

If possible, management should be conservative with IV antibiotics, nasogastric suctioning, and bowel rest. Any delay in diagnosis may result in transmural bowel necrosis. Surgical resection may be necessary for bleeding or bowel infarction.