Prepared by Glenn G. Gray, MD and Alan Tikotsky, MD of the
Department of Radiology, Lenox Hill Hospital, New York, NY.
A 43-year-old woman presented to the emergency department
complaining of severe abdominal pain, nausea, and vomiting which
awakened her from sleep 2 hours earlier. Physical examination
showed a diffusely tender, distended, tympanic abdomen with
decreased bowel sounds. Laboratory test results were within normal
limits. The patient's medical history was significant only for a
cesarean section 7 years previously. Conventional radiographs of
the chest and abdomen were obtained. A computed tomographic scan
and barium enema were performed, followed by laparotomy.
Cecal bascule with Chilaiditi's sign.
Supine and upright abdominal radiographs demonstrated dilated
loops of small bowel with several short air-fluid levels.
Hepatodiaphragmatic colonic interposition was noted. This finding
was better seen on the PA chest film, which was otherwise normal
(figure l). A CT scan of the abdomen and pelvis was performed with
oral and intravenous contrast and showed a loop of markedly
distended bowel in the pelvis (figure 2). The possibility of
volvulus was raised, but it was unclear which loop of bowel was
involved. The patient was sent for a water-soluble contrast enema.
Contrast flowed to the level of what initially appeared to
represent the cecum; however, the hugely distended loop of bowel
located in the pelvis and extending into the mid-abdomen did not
fill with contrast. This loop was thought to represent the cecum
(figure 3). Cecal volvulus was the leading diagnosis, even though a
"birds-beak" sign was not demonstrated.
The patient was taken to the operating room where a diagnosis of
cecal bascule was made. The massively distended cecum was folded
anteriorly with the appendix anterior in location. Marked
redundancy of the colon was noted, especially the transverse
portion. The cecum was decompressed and a cecopexy was performed.
The patient recovered well without complication.
Demetrius Chilaiditi originally described the radiographic
finding of hepatodiaphragmatic interposition in 1910. Since then,
Chilaiditi's sign has been regarded as a radiologic curiosity by
most physicians. The sign is uncommon, with a reported incidence of
<1% of all routine chest radiographs.
Men demonstrate this finding more often than women and it is seen
rarely in children.
Any bowel loop can be interposed, but the hepatic flexure is most
The differential diagnosis includes pneumoperitoneum and
Hepatodiaphragmatic interposition can be intermittent or
permanent and is usually an incidental finding. However, when
associated symptoms are present, the term "Chilaiditi's syndrome"
has been applied. The syndrome can present with nausea, vomiting,
flatulence, anorexia, intermittent obstruction, change in bowel
habits, and even respiratory distress and cardiac arrhythmias.
Treatment is usually conservative, consisting of bed rest,
nasogastric intubation, stool softeners, and enemas. Rarely,
surgical indications have been described for patients with
Chilaiditi's syndrome, including colonic and gastric volvuli,
internal hernia, and subphrenic appendicitis.
Multiple factors play a role in the formation of Chilaiditi's
sign. Colonic redundancy is felt to be the most significant
contributing element. Chronic constipation is the most common cause
of colonic elongation and redundancy.
Interestingly, there is a higher reported rate of Chilaiditi's
syndrome in certain psychiatric patients.
This is probably secondary to aerophagia with resultant intestinal
gaseous distention, combined with antipsychotropic medication
usage, which causes colonic hypotonia and subsequent constipation,
leading to redundancy.
A reduction in liver volume or laxity of the hepatic suspensory
ligaments also is believed to be necessary in the formation of
Other factors that may contribute to hepatodiaphragmatic
interposition include elevation of the right hemidiaphragm (e.g.,
phrenic nerve injury, diaphragmatic eventration) and enlarged lower
thoracic cage diameter (e.g., COPD, pregnancy).
Additionally, previous surgery can lead to freeing of normal
fixation of bowel.
Cecal bascule is a form of volvulus in which the cecum "folds"
anteromedially in front of the ascending colon, producing a
flap-valve occlusion at the site of flexion. It is a torsion in the
transverse plane, and causes cecal distension. The other form of
cecal volvulus, axial torsion, is a classic volvulus in which
rotation occurs in the longitudinal plane. Bascules represent up to
one-third of cecal volvuli.
Clinically, the two forms have similar presentations and
treatments, so distinction generally is not made.
Radiographically, however, bascule can be differentiated from axial
In classic axial torsion, the cecum turns upward and usually lies
in an ectopic location, often the left upper quadrant, giving the
classic "kidney-bean" appearance. With bascule, the cecum usually
falls into the pelvis, as in our case, or lies across the lower
mid-abdomen, resting centrally. In addition, because of the
anterior folding that occurs with bascule, the appendix ends up
superiorly. The "birds-beak" sign typically is not present with
bascule because there is no true twist.
Colonic redundancy with an abnormally long mesentery is almost
always found in cases of colonic volvulus; whether cecal, sigmoid,
During routine barium enemas, however, various degrees of
abnormally positioned colon can be found in normal individuals as
well. These variations are usually insignificant and are considered
normal, but some can have clinical implications. Most of these
anatomic variants are congenital in origin, resulting from
defective fixation of the primitive dorsal mesentery to the
posterior abdominal wall. Defective fusion and fixation can affect
any portion of the bowel but abnormalities are most common on the
right, resulting in abnormal mobility of the cecum and, in turn,
predisposing to volvulus or Chilaiditi's sign.
Chilaiditi's sign and cecal bascule can be explained on the
basis of similar anatomic variations. Although Chilaiditi's sign
usually is an incidental finding, it implies colonic redundancy
and, more importantly, some degree of abnormal colonic mobility. If
this sign is noted, careful inspection of the gastrointestinal
tract should be performed. If abdominal complaints are present,
Chilaiditi's syndrome can be included in the differential
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