Prepared by Amy C. Ho, BA; Karen M. Horton, MD; Charlene A.
Curry, MD; Kenneth C. Schuberth, MD; and Elliot K. Fishman, MD,
Department of Radiology, The Johns Hopkins Medical Institution,
A 14-year-old boy presented to the Emergency Department
complaining of 1 week of nonbloody diarrhea and 4 days of right
lower-quadrant pain and tenderness. The patient denied any history
of fever, vomiting, or anorexia. No previous similar episodes,
history of recent travel, or family members with similar symptoms
were reported. Physical examination revealed mild diffuse
tenderness in the right lower quadrant. There was no rebound
tenderness nor were there peritoneal signs. Bowel sounds were
normal. Laboratory values were remarkable only for an elevated
sedimentation rate of 42 mm/hr. The clinicians suspected
appendicitis. Radiologic work-up included a computed tomography
(CT) scan of the abdomen and pelvis (figure 1).
Salmonella infection of the bowel
Contrast-enhanced CT of the abdomen demonstrated thickening of
the cecal wall, regional lymphadenopathy, and moderate inflammation
involving terminal ileum (figure 1). The CT findings were most
compatible with infectious or inflammatory disease. Etiologies such
and Crohn's disease should be considered based on the CT
appearance. There was no evidence of appendicitis. A stool culture
was positive for
. The patient was treated successfully with antibiotics and the
is a major cause of enteric infections and manifests as an acute
onset of diarrhea, fever, abdominal pain, and/or vomiting. The
disease tends to occur in outbreaks, particularly in warm summer
months when unrefrigerated foods spoil rapidly. Although the small
intestine is generally the principal site of involvement in human
salmonellosis, abnormality of the colon has been recognized since
1969, when Boyd
described necropsy findings of 6 patients with infections caused by
. Several published reports confirm that colonic abnormality is
common in nontyphoid salmonellosis.
Given the high incidence of salmonellosis in the general
population, the scarcity of any radiologic reports describing
terminal ileum or colonic involvement is worthy of notice. The
explanation lies in the fact that most individuals developing an
acute infection do not seek specialized medical assistance, do not
undergo radiographic or endoscopic work-up, and, when necessary,
are treated empirically but successfully with supportive therapy
and broad-spectrum antibiotic therapy.
Only three cases of
involving the colon have been described on CT findings. In a group
of 3 patients with
infection, CT examination by Balthazar et al
showed slight (5 to 8 mm) symmetrical and homogenous thickening of
the wall of the terminal ileum as well as slight (3 to 5 mm)
circumferential thickening of the cecum and descending colon. In
addition, thickening of the sigmoid colon and the wall of the
rectum was seen in 1 case, and small regional mesenteric nodes,
<1 cm in size, were visualized in another case.
In the past, barium enema examination has been used to evaluate
patients with suspected
colitis. In those few reports, barium enema usually demonstrated a
pancolitis with superficial ulcerations, loss of haustration,
and irregular thickening of folds on postevacuation views.
Segmental colitis in the left colon was described only rarely, and
salmonellosis involving only the terminal ileum and, to our
knowledge, cecum has not been previously reported.
In our patient, CT demonstrates moderate soft-tissue thickening
of the ileum and cecum with pericecal stranding and
lymphadenopathy. Although our patient had salmonellosis, this is a
nonspecific appearance, and other infectious etiologies should be
included in the differential diagnosis. Intestinal tuberculosis
most frequently involves the ileocecal region and may be manifested
by bowel wall thickening, luminal narrowing,
and pericecal lymphadenopathy, with the nodes being either
homogeneous or of lower attenuation centrally.
enterocolitis usually affects the terminal ileum and right side of
the colon, causing fold thickening, nodules, and ulceration.
However, luminal narrowing is not characteristic of
Other infectious and noninfectious inflammatory processes may
also be associated with thickened folds and regional
lymphadenopathy, including appendicitis and Crohn's disease. In
appendicitis, the wall of the diseased appendix is thickened
circumferentially, and periappendiceal inflammation is
characteristically present. Secondary inflammatory and edematous
changes associated with appendicitis can cause slight mural
thickening of the small bowel or cecum. These changes have the
potential to be misinterpreted as primary ileocolic inflammatory
In Crohn's disease, classic barium enema and CT findings include
nodular bowel wall thickening, particularly in the terminal ileum.
Additionally, segmental disease of the colon is often seen.
However, while the imaging findings of Crohn's disease overlap with
infectious etiologies, the clinical history tends to have a more
chronic course with periodic exacerbations.
Finally, in some patients, neoplasms involving the ileocecal
region, such as lymphoma, may be associated with mesenteric
adenopathy and mural involvement of the bowel. These can manifest
as circumferential mural thickening or as a focal solid mass,
although the mass is usually more extensive.
We report a rare case of ileocecal salmonellosis in a
14-year-old patient, which was characterized by bowel wall
thickening, inflammation, and regional lymphadenopathy on CT. The
differential diagnosis for such a presentation is broad,
encompassing infectious, inflammatory, and neoplastic processes.
Although in a pediatric patient
would be a more common diagnosis, the radiologist must be aware of
the range of possible etiologies. A definitive diagnosis requires
stool, blood, or tissue-fluid cultures so appropriate antibiotic
therapy can be initiated when needed. Early detection will help
prevent complications of undiagnosed colitis, in-cluding toxic
megacolon, bleeding, over-whelming sepsis, and death.