The association between constipation and urinary retention is well known (1,2).
Several mechanisms may explain this relationship, including sharing of the innervations of the internal anal and urinary sphincters via S2-S4 nerve roots, and the presence of impacted stool in the rectum leading to invaginations in the posterior wall of the bladder and urethral obstruction (1,2).
Interestingly, in laboratory experiments involving rats, rectal distention with a balloon diminished bladder contractility (3). So, along with many other factors, constipation should routinely be considered a potential cause of acute urinary retention.
Liked this post? Download the app on your smart phone and sign up below to catch future pearls right into your inbox, all for free!
References
1. Selius BA, Subedi R. Urinary retention in adults: diagnosis and initial management. Am Fam Physician 2008;77:643-650. https://www.aafp.org/afp/2008/0301/p643.html
2. Ariza Traslavina, Del Ciampo LA, Ferraz IS. Acute urinary retention in a pre-school girl with constipation. Rev Paul Pediatr 2015;33:488-492. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4685571/
3. Miyazato M, Sugaya K, Nishijima S, et al. Rectal distention inhibits the spinal micturition reflex via glycinergic or GABAergic mechanisms in rats with spinal cord injury. Urol Int 2005;74:160-65. https://www.ncbi.nlm.nih.gov/pubmed/15756069
Disclosures: The listed questions and answers are solely the responsibility of the author and do not necessarily represent the official views of Massachusetts General Hospital, Harvard Catalyst, Harvard University, their affiliate academic healthcare centers, or its contributors. Although every effort has been made to provide accurate information, the author is far from being perfect. The reader is urged to verify the content of the material with other sources as deemed appropriate and exercise clinical judgment in the interpretation and application of the information provided herein. No responsibility for an adverse outcome or guarantees for a favorable clinical result is assumed by the author. Thank you!