Fecal Incontinence: Pathogenesis and complications
Note: The majority of fecal incontinence is multifactorial in cause
Authors: Timothy Fu Reviewers:
Chronic bowel straining
Difficult vaginal delivery
Direct internal anal sphincter impairment (controls ~70% of anal resting tone)
↓ anal resting tone
Aging:
Degene- ration of muscle fibers
Movement disorders (e.g. arthritis, Parkinson’s); aging is a risk factorà ↓ mobility
↓ timely access to bathrooms
Inflammation
of colon (e.g., Ulcerative colitis, Radiation proctitis)
↓ capacity of
rectal smooth muscle to stretch
↓ capacity to store stool
↑ urgency of defecation
↑ reflex relaxation of internal anal sphincter
Chronic diarrhea, diarrhea- predominant irritable bowel syndrome, laxatives
Yan Yu* Erika Dempsey* * MD at time of publication
Stretch injury of Pelvic surgery
Chronic constipation
Build up of solid, immobile mass of stool in the rectum
Loose stool is able to flow around impacted stool, exiting anal canal (overflow diarrhea)
Sensory neuro- pathy (e.g. Diabetes)
Altered
mental conditions (e.g. stroke, dementia)
pudendal nerve (innervating the pelvic muscles and external anal sphincter)
Local neuronal damage
Impaired pelvic muscle and external anal sphincter motor control
Pelvic trauma
Rectal prolapse
Direct external anal sphincter impairment
↑ Stool volume
↑ Loose stools
Rectal hyposensitivity (↓ perception of rectal distension)
Patient fails to sense rectal fullness and voluntarily releases their external anal sphincter
Voluntary external anal sphincter contraction is no longer sufficient in closing the anus
Loose stool is more prone to escape through anal canal compared to solid stool
Continence mechanisms are impaired
Fecal Incontinence: The unintentional loss of solid or liquid stool
Skin Skin
Continence mechanisms are intact, but overwhelmed or ignored
infection Skin erythema
erosion
Inability to control what is widely considered a basic, fundamental bodily process
↑ caretaker burden Social stigma
↑ skin contact with acidic irritant (stool)
↑ rate of institutionalization, (e.g., admission into long-term care)
↓ confidence, sense of agency
↑ stress, anxiety
Skin inflammation
↓ social activity, work ↓ help-seeking ↓ treatment
Legend:
Pathophysiology
Mechanism
Sign/Symptom/Lab Finding
Complications
Published May 2, 2020 on www.thecalgaryguide.com