Typhlitis means inflammation
of the cecum. In 1960, Bierman and Amronin first coined the term "ileocecal
syndrome" to describe inflammation and/or necrosis of the cecum, appendix,
and/or ileum in patients with leukemia. Typhlitis subsequently has been
associated with aplastic anemia, lymphoma, AIDS, and immunosuppression
following renal transplantation or during treatment of malignancy.
Pathologically, typhlitis represents inflammation and/or necrosis of the
cecum, appendix, and/or ileum. The etiology of typhlitis is unknown, but
its pathogenesis is multifactorial. Profound neutropenia, with total neutrophil
counts of less than 1000/mm3, appears to be a universal predisposing factor.
Mucosal injury from cytotoxic drugs plays an important role in the typhlitis
observed during chemotherapy.
Cecal distension in typhlitis may impair the blood supply, leading to
mucosal ischemia and ulceration. Infection may be involved, especially
cytomegalovirus. Bacterial invasion leads to transmural penetration and,
ultimately, perforation. Mucosal and submucosal necrosis can result in
intramural hemorrhage. Neoplastic infiltration may be involved in some
The maximum normal colonic wall thickness on CT is 3 mm. When the colon
is distended with stool, fluid, or oral contrast, the normal colonic wall
is nearly imperceptible. Pericolonic fat should demonstrate homogeneous
fat attenuation. Typhlitis usually is confined to the cecum, appendix,
and terminal ileum; however, it can cause a pancolitis extending distally
from the cecum. CT demonstrates circumferential and occasionally eccentric
low-attenuation colonic wall thickening and cecal distension. High attenuation
within the thickened colonic wall may represent hemorrhage, and inflammatory
pericolonic stranding of mesenteric fat is common.
CT readily identifies complications, including pneumatosis coli, pneumoperitoneum,
pericolonic fluid collections, and abscess. These complications may require
urgent surgical management.
Dr. Bhujang Pai, Hinduja Hospital, Mumbai