Idiopathic megarectum is characterized by abnormal, pronounced rectal dilatation in the absence of identifiable organic pathology. Idiopathic megarectum is uncommon and under-recognized. This study aims to describe the clinical features and management of idiopathic megarectum.
A retrospective review was undertaken on patients diagnosed with idiopathic megarectum with or without idiopathic megacolon over a 14-year period until 2021. Patients were identified from the hospital’s International Classification of Diseases codes, and pre-existing clinic patient databases. Patient demographics, disease characteristics, healthcare utilization and treatment history data were collected.
Eight patients with idiopathic megarectum were identified; half of the patients were female, with the median age of symptom onset being 14 years (interquartile range [IQR] 9-24). The median rectal diameter measured was 11.5 cm (IQR 9.4-12.1). The most common presenting symptom was constipation, bloating and faecal incontinence. All patients required prior sustained periods of regular phosphate enemas and 88% were using ongoing oral aperients. Concomitant anxiety and or depression were found in 63% of patients and 25% were diagnosed with an intellectual disability. Healthcare utilization was high with a median of three emergency department presentations or ward admissions related to idiopathic megarectum per patient over the follow-up period; 38% of patients required surgical intervention during the period of follow-up.
Idiopathic megarectum is uncommon and associated with significant physical and psychiatric morbidity and high healthcare utilization.

Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.