Chilaiditi's sign

To the Editor,

Chilaiditi sign is characterised by interposition of the intestine (usually the hepatic angle of the colon) between the liver and right hemidiaphragm. It is a rare entity that was first described by Demetrius Chilaiditi, a Greek radiologist, in 1910.¹ It is more common in men (4:1 ratio), and is generally an incidental finding that appears in between 0.02% and 0.14% of radiological studies performed for any reason.² Its cause is unknown, although it is probably multifactorial.

Chilaiditi sign is asymptomatic. When associated with symptoms, it is called Chilaiditi syndrome. The most common symptoms are digestive: vomiting, anorexia, constipation and bloating. It can also be associated with respiratory symptoms like dyspnoea or pleuritic pain. As the physical examination is usually unremarkable, it is often underdiagnosed.³

The suspensory ligaments and fixation of the colon normally impede interposition of the colon between the liver and diaphragm. Chilaiditi syndrome has been associated with several predisposing factors (Table 1) that can change the relationship between the liver, colon and diaphragm.^2,4

Table 1.

Predisposing factors for Chilaiditi syndrome.

Liver

Hepatic ptosis

Cirrhosis

Atrophy of the liver

Alterations in the suspensory ligament of the liver

Intestinal

Megacolon

Meteorism

Abnormal colonic motility

Alterations in the suspensory ligament of the colon

Abnormal gas accumulation due to aerophagia

Diaphragmatic

Diaphragmatic thinning

Elevation right hemidiaphragm

Eventration

Phrenic nerve injury

Changes in intrathoracic pressure (e.g. emphysema)

Others

Enlargement of the lower chest cavity (chronic obstructive pulmonary disease)

Increased intra-abdominal pressure (obesity, multiple pregnancies, ascites)

Mental delay and schizophrenia

Intra-abdominal adhesions (due to previous surgery or neoplasia)

Previous endoscopic procedures

It is important to identify the presence of Chilaiditi sign in patients with predisposing factors in order to minimise iatrogenesis, as in the case of percutaneous transhepatic procedures or liver biopsy in cirrhotic patients or during colonoscopies.

Hepatodiaphragmatic interposition is generally diagnosed by plain X-ray. The typical image shows air below the diaphragm, with visible haustra between the liver and surface of the diaphragm (Fig. 1). In case of diagnostic uncertainty, the location of the air will not change when the patient changes posture.

Figure 1.

Interposition of the intestine between the liver and right hemidiaphragm in an asymptomatic patient. Haustra can be observed (white arrow). Findings consistent with Chilaiditi sign.

Differential diagnosis should be made mainly with pneumoperitoneum, typically seen on X-ray as a half-moon shape extending below the diaphragm, with no visible haustra, and which changes with posture.

Other entities that should be included in the differential diagnosis are subphrenic abscess, intestinal pneumatosis, infected hydatid cyst and liver tumour.² Cases have also been documented with symptoms similar to renal colic, so this should also be considered in the differential diagnosis of this disease.

In the case of diagnostic uncertainty, ultrasound or computed axial tomography are the most commonly used additional studies.

No treatment is required in the case of asymptomatic patients. In cases of Chilaiditi syndrome with no severity criteria, treatment is initially conservative: bed rest, decompression with a nasogastric tube, intravenous fluids, enemas, laxatives and discontinuation of potentially related medication. Despite treatment, 26% of symptomatic patients eventually require surgery (colectomy, hepatopexia or colopexia).^5,6