DDSEP Motility 6 Flashcards
What is the difference in internal and external anal sphincter?
IAS gives resting tone and is controlled by smooth muscle. It is primary deterrent for involuntary egress of stool (especially nighttime) with tonic contraction unless stimulated.
EAS is striated muscle we control
What two responses do you get from distention of the rectum?
- Rectoanal Inhibitory Reflex (RAIR) where you have IAS relaxation
- Simultaneous contraction of the EAS to maintain continence.
What is a new diagnostic test for determining lumbar and sacral plexus neuropathy?
Translumbosacral anorectal magnetic stimulation test
What are some oral/OTC treatments for FI?
Dietary modifications such as lactose or fructose restriction.
Fiber, laxatives.
Loperamide before meals.
What role does biofeedback have for FI?
Can be helpful if the cause for FI is reduced rectal sensation.
Biofeedback is also effective in improving muscle function and anorectal coordination and remains the mainstay of treatment for FI.
What surgical/neurologic interventions are available for FI?
Anal sphincter surgery with overlap sphincteroplasty is not effective in FI.
Sacral nerve stimulation and anal submucosal injection of dextranomer is effective and approved.
What is the pathophysiology of Hirchprungs?
You have segments that are missing the myenteric ganglion cells causing the affected segments to be contracted with the segment above being dilated.
Can you identify Hirschprung’s disease later in life?
Yes, can be a less dramatic presentation and have been misdiagnosed in the past.
Look for chronic constipation and recurrent fecal impaction.
How is HIrschprung’s diagnosed?
You typically get barium enema, manometry, rectal biopsy. The BE can miss short segment HD!
What finding on manometry is pathognomonic for HD?
The aganglionic segment extends from IAS proximally, so rectal distention will no longer cause IAS relaxation- so you lose the RectoAnal Inhibitor Reflex/RAIR)
This is why manometry is the test of choice for ultrashort segment Hirschprung’s disease.
What are false positives for the loss of RAIR on rectal manometry?
A capacious rectum from megacolon or chronic fecal retention will cause balloon stimulation to not stimulate the RAIR reflex.
This is why you would follow with deep suction biopsy of rectal mucosa (will show absence of ganglion cells and hypertrophy of nerve fibers, so if you see ganglion cells 1-2cm proximal to the anus rules out HD)
