Can an abdominal ultrasound diagnose stool impaction?

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Last updated: June 4, 2025View editorial policy

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From the Research

An abdominal ultrasound can be used to diagnose stool impaction, with a recent study suggesting its potential as a non-invasive diagnostic tool. According to a 2024 systematic review and meta-analysis 1, transabdominal ultrasound may be valuable in diagnosing functional constipation and identifying fecal impaction in children, with estimated mean sensitivity and specificity of 0.68 and 0.81, respectively. The study found that measuring transverse rectal diameter via transabdominal ultrasound can help diagnose functional constipation, with cut-off values ranging from 2.4 cm to 3.8 cm.

Some key points to consider when using abdominal ultrasound for this purpose include:

  • The diagnostic accuracy of transabdominal ultrasound for functional constipation and fecal impaction is still being researched, with heterogeneous study methods and a lack of age-dependent normal values impairing current clinical recommendations 1.
  • Other imaging methods, such as abdominal X-rays (KUB) and CT scans, may be preferred for diagnosing stool impaction due to their ability to provide a clearer overall view of the bowel and demonstrate the extent and location of fecal loading.
  • Clinical evaluation, including digital rectal examination, remains essential for patients with suspected stool impaction, as it can directly confirm the presence of impacted stool in the rectum 2, 3.
  • Treatment for stool impaction typically involves manual disimpaction, enemas, oral laxatives, and stool softeners, with long-term management focusing on preventing recurrence through adequate hydration, fiber intake, and sometimes maintenance laxative therapy.

Overall, while abdominal ultrasound may be a useful diagnostic tool for stool impaction, its use should be considered in conjunction with other diagnostic methods and clinical evaluation to ensure accurate diagnosis and effective management.

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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