To assess the incidence of Chilaiditi sign and syndrome in myotonic dystrophy type 1 (DM1).

Chilaiditi syndrome is a phenomenon where there is an interposition of the colon between the liver and the abdominal wall leading to clinical symptoms. This is distinct from Chilaiditi sign for which there is radiographic evidence of the interposition but is asymptomatic. Chilaiditi sign is rare in the general population and the incidence is reported to be 0.025-0.28%. Commonly, this condition causes no symptoms, however, it sometimes causes abdominal distention, abdominal pain, constipation, and respiratory disturbance intermittently. It is speculated that the intestinal, hepatic, and diaphragmatic etiologies may contribute to the pathogenesis of this syndrome. Obesity is also known as a risk factor. Although DM1 causes both diaphragm muscle weakness and obesity, the incidence of Chilaiditi syndrome in DM1 remains unclear.

We experienced 32 patients with DM1 between April 2011 to September 2018. We retrospectively analyzed the incidence of Chilaiditi sign using abdominal CT scans and investigated the symptoms that may be associated with Chilaiditi sign (Chilaiditi syndrome).

Chilaiditi sign was observed in 4 out of 32 patients with DM1 (12.5%). The incidence is much higher than the general population. Among them, one patient had obesity (BMI > 25). One patient developed atelectasis of the right lower lobe due to diaphragm elevation associated with Chilaiditi sign, and this patient had severe diaphragmatic muscle weakness revealed by diaphragm echo. Other three patients were asymptomatic.

Chilaiditi sign is frequently observed in patients with DM1, probably due to diaphragmatic muscle weakness and obesity. This condition may cause exacerbation of respiratory dysfunction via atelectasis in addition to the gastrointestinal manifestation. Further accumulation of patients is required to determine the incidence and clinical importance of Chilaiditi sign and syndrome in DM1.