Megarectum in Adults (MEGA-ORIGINE)

University Hospital, Rouen

Status: Begins enrollment this month

Conditions: Idiopathic Megarectum

Treatments: Other: Idiopathic megarectum group; Other: Constipated patient group

Study type: Observational

Funder types: Other

Identifiers

NCT07599527

2026-A00636-45 (Other Identifier)

2026/0116/OB

Details and patient eligibility

About

Severe functional constipation associated with a pathological increase in rectal volume, with or without colonic dilation, is known as megarectum. In the absence of an organic cause, megarectum is called idiopathic. This condition can begin at birth, in childhood, or in adulthood. The exact incidence of idiopathic megarectum (IM) is unknown, but it is considered a rare condition. Clinically, IM is usually considered in the context of chronic constipation that is refractory to traditional treatments and accompanied by rectal distension, abdominal pain, encopresis, and recurrent fecal impaction. The pathophysiological basis of IM remains poorly understood. A study using a rectal barostat-a device that measures rectal capacity and compliance (the rectum's ability to distend) by controlled distension of a rectal balloon-identified two distinct subgroups of patients with MI: (1) those with increased rectal compliance, who can be described as having "physiological" megarectum, in which marked rectal hyposensitivity-characterized by the absence of perception of rectal distension-and hypocontractility lead to chronic fecal accumulation and progressive overdistension due to loss of rectal elasticity; and (2) those with normal rectal compliance, who can be considered to have anatomical megarectum. It is not yet known whether these subgroups reflect different underlying etiologies. Furthermore, in patients with physiological megarectum, it is unclear whether the condition is primary or secondary to long-term rectal distension.

Full description

The aim of this study is to identify and characterize elements of the clinical history, particularly early ones, associated with the disease, in order to contribute to the understanding of its pathophysiology.

To this end, the project aims to analyze the personal and family histories of patients with idiopathic bowel dysfunction (BD) and compare them with a population of constipated patients without BD, in order to determine the chronology of the onset of the condition (from birth, childhood/adolescence, or later) and to evaluate the risk factors for BD. It is also planned to describe the population of patients with BD to confirm whether or not different subgroups exist.

A better understanding of the pathophysiology of BD should make it possible to prevent the condition (if secondary to dyssynergia present in childhood) and/or to provide earlier, more appropriate management, thus avoiding acute episodes of bowel obstruction.

Enrollment: 120 estimated patients

Sex: All

Ages: 18+ years old

Volunteers: No Healthy Volunteers

Inclusion criteria

• Idiopathic megarectum (IM) group:
• Adult patients presenting with chronic constipation according to the Rome criteria;
• Patients with megarectum suspected by anorectal manometry and confirmed by rectal barostat;
• Isolated, idiopathic megarectum (no known cause);

Constipated group:

• Constipated adult patients presenting consecutively with chronic functional constipation according to the Rome criteria;
• Patients without megarectum suspected by anorectal manometry.

Exclusion criteria

• Patients who are not constipated;
• Hirschsprung's disease;
• Patients with anorectal malformation;
• Patients with known neurological conditions;
• Patients with endocrine disorders that may cause constipation;
• Patients taking constipating medications such as morphine or neuroleptics;
• Patients with a potential organic and/or drug-induced cause of constipation;
• Constipation secondary to medication;
• Patients unable to complete a questionnaire;
• Patients deprived of their liberty, under guardianship, or curatorship