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NCT Number: NCT07599527

Megarectum in Adults

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.

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Key information

Age range

18 year and older

Sex eligibility

All sexes

Study type

Observational

Primary location

Digestive Physiology Department

Rouen, 76031, France

About this study

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.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

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

Treatment and study plan

Idiopathic megarectum group

Other

questionnaires documented by patients with suspected megarectum on anorectal manometry and confirmed by rectal barostat

Constipated patient group

Other

questionnaires completed by adult patients consulting for functional constipation without suspected megarectum on anorectal manometry

Primary outcomes

  1. To determine if patients with Idiopathic MegaRectum (MI) have a history of earlier constipation in childhood than constipated patients without megarectum

    Time frame: 1 day

    This involves comparing the history of constipation that may reveal anorectal dysfunction in childhood in constipated adults with MI and in constipated control subjects without megarectum through clinical questioning.

  2. To determine if patients with Idiopathic MegaRectum (MI) have a history of more digestive symptoms in childhood than constipated patients without megarectum

    Time frame: 1 day

    This involves comparing the history of digestive symptoms that may reveal anorectal dysfunction in childhood in constipated adults with MI and in constipated control subjects without megarectum through clinical questioning.

Secondary outcomes

  1. Comparison of environmental factors in constipated adults with MI and in constipated control subjects without megarectum

    Time frame: 1 day

    Determination of the presence of environmental factors in childhood: breastfeeding, repeated early antibiotic therapy, drug treatment in childhood and indication (antibiotics, anticholinergic treatments, opiates, morphine, etc.) through clinical questioning

  2. Comparison of environmental factors in constipated adults with MI and in constipated control subjects without megarectum

    Time frame: 1 day

    Presence of psychosocial factors in childhood: psychosocial or school-related stress, anxiety and depressive disorders as revealed by clinical questioning

  3. megarectum phenotyping

    Time frame: 1 day

    The aim is to phenotype the megarectum using anorectal manometry to distinguish an "acquired" profile from a "congenital" profile. The measured indicators will be anal tone, amplitude and duration of voluntary contraction, the presence of the rectoanal inhibitory reflex; the amplitude of the rectoanal inhibitory reflex at 30 ml of rectal distension; the presence of rectosphincter dyssynergia; the amplitude of rectal contraction during straining; the percentage of anal relaxation during straining; the residual pressure during straining; the threshold volume for perceiving rectal distension; the constant perceiving volume; the maximum tolerable volume; and rectal compliance.

  4. megarectum phenotyping

    Time frame: 1 day

    The aim is to phenotype the megarectum using Balloon evacuation test is to assess a patient's ability to evacuate stools, particularly in cases of constipation or suspected defecation disorder. This test is based on the concept of success or failure.

    Success:

    The patient manages to expel the balloon within a timeframe considered normal (often < 1 to 2 minutes, according to protocols).

    This suggests that the recto-anal evacuation mechanism is generally functioning correctly.

    Failure:

    The patient is unable to expel the balloon or takes an abnormally long time.

    This may indicate a defecation disorder, for example:

    anorectal dyssynergia (poor muscle coordination), rectal hypocontractility, or a functional obstruction to evacuation.

  5. megarectum phenotyping

    Time frame: 1 day

    The aim is to phenotype the megarectum using rectal Barostat is to allow the measurement of rectal distension volumes to obtain the desired rectal pressure

  6. megarectum phenotyping

    Time frame: 1 day

    The aim is to phenotype the megarectum using rectal Barostat is to allow the measurement of rectal distension volumes to obtain the rectal compliance

  7. megarectum phenotyping

    Time frame: 1 day

    The aim is to phenotype the megarectum using rectal Barostat is to allow the measurement of rectal distension volumes to obtain the maximum tolerable volume;

  8. megarectum phenotyping

    Time frame: 1 day

    The aim is to phenotype the megarectum using imagery is to assess rectal size in diameter

  9. megarectum phenotyping

    Time frame: 1 day

    The aim is to phenotype the megarectum using imagery is to assess colon size in diameter

  10. Constipation Severity Score Evaluation

    Time frame: 1 day

    This assessment is carried out using the Kess scores. The KESS score (KESS score = Knowles-Eccersley-Scott Symptom score) is intended to assess the severity of chronic constipation. It takes into account:

    frequency of bowel movements; difficulty passing stool; feeling of incomplete evacuation; use of laxatives; pain or straining; duration of the problem.

    The higher the score, the more severe the constipation.

  11. Constipation Severity Score Evaluation

    Time frame: 1 day

    This assessment is carried out using the Francis scores. The Francis score (or IBS-SSS: Irritable Bowel Syndrome Severity Scoring System) is used to measure the severity of Irritable Bowel Syndrome.

    It assesses:

    intensity of abdominal pain; frequency of pain; bloating/distension; bowel movement irregularities; and impact on quality of life.

    The total score ranges from 0 to 500:

    < 75: no or very mild symptoms; 75-175: mild; 175-300: moderate; 300: severe.

  12. fecal incontinence severity score

    Time frame: 1 day

    The Cleveland Clinic score will be used to assess the severity of chronic constipation. This score assesses several factors:

    frequency of bowel movements; difficulty of defecation; straining; feeling of incomplete evacuation; abdominal pain; time spent on the toilet; need for assistance (laxatives, enemas, digital defecation); duration of constipation.

    Each item is assigned a number of points.

    In practice:

    < 8: mild constipation; 8-15: moderate constipation; > 5: severe constipation

  13. Quality of life score assessment

    Time frame: 1 day

    The quality of life score will be assessed using the GIQLI questionnaires. The GIQLI (Gastrointestinal Quality of Life Index) is a questionnaire used to measure quality of life related to digestive diseases. The questionnaire comprises 36 questions. Each question is scored from 0 to 4 on the following scale:

    0 = very poor condition / significant symptoms 4 = no problems The maximum score is 144. A high score indicates good digestive health. A low score indicates significant impact of digestive disease.

  14. Quality of life score assessment

    Time frame: 1 day

    The quality of life score will be assessed using the PAC-QOL questionnaire. The PAC-QOL (Patient Assessment of Constipation - Quality Of Life) is a specific questionnaire used to assess the impact of chronic constipation on quality of life.The questionnaire typically contains 28 questions divided into several areas: 1) physical discomfort; 2) psychosocial discomfort; 3) worries/concerns; 4) satisfaction. Each item is rated on a scale of 0 to 4.

    A low score indicates a good quality of life; A high score indicates a significant impact of constipation.

  15. Quality of life score assessment

    Time frame: 1 day

    The quality of life score will be assessed using the FIQL questionnaires. The FIQL (Fecal Incontinence Quality of Life Scale) is a questionnaire designed to assess the impact of fecal incontinence on quality of life. The FIQL measures the psychological, social, and emotional impact of fecal incontinence, going beyond simply the frequency of leakage.

    It explores, in particular: social discomfort; anxiety; self-image; limitations in daily activities; emotional impact.

    The FIQL comprises 29 questions divided into 4 domains:

    • Lifestyle; 2) Behavior; 3) Depression/Self-Perception; 4) Embarrassment. Each question is scored on a scale of 0 to 4. A high FIQL indicates a better quality of life. A low FIQL indicates a significant impact of incontinence.
  16. Predictive factors for each of these profiles in terms of medical history

    Time frame: 1 day

    Identify predictive factors for each of these profiles in terms of family history during the clinical interview with the patient (severe constipation leading to surgery (and type of surgery) or difficult to treat medically, onset of constipation in childhood or adulthood, Hirschsprung's disease, colonic inertia, chronic intestinal pseudo-obstruction, gastroparesis, stoma, gastrostomy, enteral or parenteral nutrition, anorectal malformation, neurological malformation)

  17. Predictive factors for each of these profiles in terms of medical history

    Time frame: 1 day

    Identify the predictive factors of each of these profiles in terms of personal history during the clinical interview with the patient (severe constipation requiring surgical intervention (and type of intervention) or difficult to treat medically, onset of constipation in childhood or adulthood, Hirschsprung's disease, colonic inertia, chronic intestinal pseudo-obstruction, gastroparesis, stoma, gastrostomy, enteral or parenteral nutrition, anorectal malformation, neurological malformation).

  18. Current symptoms

    Time frame: 1 day

    Identify current symptoms: encopresis, fecal incontinence, dyschezia, abdominal bloating, abdominal pain, number of bowel movements per week, stool consistency according to the Bristol Stool Scale

  19. Predictive factors for each of these profiles in terms of medical history

    Time frame: 1 day

    information search regarding the age of toilet training in childhood during the clinical interview with the patient.

  20. Predictive factors for each of these profiles in terms of medical history

    Time frame: 1 day

    information search regarding childhood digestive symptoms during the clinical interview with the patient.

  21. Predictive factors for each of these profiles in terms of medical history

    Time frame: 1 day

    information regarding stool frequency in childhood and stool consistency in childhood during the clinical interview with the patient.

  22. Predictive factors for each of these profiles in terms of medical history

    Time frame: 1 day

    research for information regarding the factors identified as triggers of constipation during the clinical interview with the patient.

  23. Predictive factors for each of these profiles in terms of medical history

    Time frame: 1 day

    information search regarding possible pain during defecation during the clinical interview with the patient.

Study contacts

Contact information is provided by the study sponsor or research team.

Nabila NL LAAJAIL, Director

CONTACT

[email protected]

02 32 88 82 65 ext. +33

vincent VF FERRANTI, ARC

CONTACT

[email protected]

02 32 88 82 65 ext. +33

Sponsors and collaborators

Lead sponsor

University Hospital, Rouen

Other

Registry information

Official study title

Megarectum in Adults: Congenital or Acquired Pathology?

Acronym: MEGA-ORIGINE

Important dates

Study start
2026
Primary completion
2028
Study completion
2028
First posted
May 20, 2026
Registry last updated
May 20, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.