7- Bowel Dysfunction Flashcards
Draw & explain bowel innervation. ππ (OSCE)
SYMPATHETIC NERVOUS SYSTEM
Upper 1/3 Superior mesentric ganglion T4-T12 (Celiac ganglion β Autonomic Dysreflexia)
Lower 2/3 Inferior mesentric ganglion and hypogastric n. T10-L2 β Internal Anal Sphincter
Function: Inhibits colonic contractions β storage
PARASYMPATHETIC NERVOUS SYSTEM
Upper 1/3 Vagus nerve (CNX) which innervates proximal to mid-transverse colon
Lower 2/3 Pelvic n. (S2βS4) β Internal Anal Sphincter
Function: Enhances colonic motility β defecation
INTERNAL ANAL SPHINCTER
Sympathetic tone causes contraction of the internal anal sphincter
Parasympathetic tone causes relaxation of sphincter tone.
EXTERNAL ANAL SPHINCTER
Pudendal nerve (S2βS4)
Function: voluntary control β maintain continence.
Sequence of event in normal defecation What are the 3 muscles important for maintaining fecal continence? ππ MOCK 2021
(A) Defecation is prevented by increased tone of
- Internal anal sphincter (IAS)
- External anal sphincter (EAS)
- Puborectalis
(B & C) Defecation is initiated by
- Relaxing puborectalis muscle and EAS
- Contraction of levator ani, abdominals, and diaphragm
- Rectum contraction to complete evacuation
Spinal Cord Medicine Principles and Practice - 2nd Edition (2010)
Braddom 4th Edition Chapter 21 Bowel pg454 Figure 21-4
Compare internal and external anal sphincter. ππ
Internal Anal Sphincter
- Smooth Muscles
- Sympathetic (contraction)
- Parasympathetic (relaxation)
External Anal Sphincter
- Circular band of striated skeletal muscle (Part of the pelvic floor)
- Somatic innervation from the pudendal nerve (S2βS4) for voluntary continence
Cuccurollo 4th Edition Chapter 7 SCI pg582
Auerbachβs (Myenteric) plexus is located in? why itβs important?
Auerbachβs (Myenteric) plexus
- Part of autonomic nerves system of the bowl
Location
- Muscularis propria between circular and longitudinal muscle layers
Function
- Control gut secretions
- Control blood flow
- Muscular activity giving the colon the ability to produce peristalsis.
π‘ After SCI, autonomic (sympathetic/ parasympathetic) and somatic neural input is disrupted, but the enteric system remains intact
List two types of dietary fiber, and their effects on the GI system.
Insoluble fiber
Promotes the movement and bulk of stool
Beneficial to those who struggle with constipation or irregular stools.
Soluble fiber
Dissolves in water to form a gel-like material.
It can help lower blood cholesterol and glucose levels.
List 6 symptoms of fecal impaction in the elderly. ππ
GENERAL
- Anorexia
- Confusion
- Agitation
- Worsening psychosis
REAGONAL
- Nausea & Vomiting
- Constipation
- Abdominal pain
- Fecal incontinence (Paradoxical diarrhea)
- Urinary frequency
- Urinary overflow incontinence
https://www.researchgate.net/figure/Symptoms-Associated-with-Fecal-Impaction_tbl1_235756213
List 4 major reflexes that influence bowel function. π
1- Gastrocolic reflex
- Nerve: vagus nerve
- Contraction of the colon occurring with gastric distention
- Patients to be instructed to perform their bowel programs 20 to 30 minutes after a meal.
- Increased colonic activity occurs in the first 30 to 60 minutes after a meal (usually within 15 minutes)
2- Colo-colonic reflex
- Inhibition of contraction in one portion of the intestinal tract by distention of another
- Mediated by prevertebral ganglia, not the spinal cord, so they likely would be unaffected by SCI
3- Rectocolic defication reflex
- Nerve: pelvic nerve S2-4 (parasympathetic)
- Occurs when rectal contents stretch the bowel wall reflexively
- Relaxing the internal anal sphincter and leading to left colonic contraction
- Digital stimulation is accomplished by gently inserting a gloved, lubricated finger into the rectum, and slowly rotating the finger in a clockwise circular motion until relaxation of the bowel wall is felt or stool/flatus passes (approximately 1 minute).
- Suppositories and digital stimulation cause the bowel wall to stretch and take advantage of this reflex.
4- Rectoanal inhibitory reflex
- Transient relaxation of the IAS stimulated by a rise in rectal pressure
- Occurs during sleep and throughout the day
5- Guarding reflex
- Preserve continence while sensory receptors of the anorectal junction appraise the contents.
Delisa 5th Edition Chapter 51 Neurogenic Bowel & Bladder pg1375-1377
Cuccurollo 4th Edition Chapter 7 SCI pg584
Name 5 changes in bowel function / GI complications that occur after SCI? π
TWO MAIN DYSFUNCTION
- Fecal Incontinence: Diarrhea, Electrolyte Imbalance, Dehydration, Leak, Accidents
- Fecal Impaction: Constipation, Abdominal Pain, Bloating, and Early Satiety, GERD
ORGANS
- ESOPHAGUS: Dysphagia, GERD
- STOMACH: Gastroparesis, Bloating
- INTESTINE: Superior mesenteric artery syndrome, Increased transit time, Decreased bowel/colonic motility, Constipation, Diverticulosis
- RECTUM: Hemorrhoids 74%, Rectal prolapse
- SPHINCTER: Flaccid sphincter (leaking, and accidents), Spastic sphincter (fecal impaction), Fissures
- RISK of Autonomic dysreflexia
SCIRE, bowel management; Braddom pg 627.
Spinal Cord Medicine Principles and Practice Table 31.1
Cuccurullo 4th Edition Chapter 7 SCI pg 585.
List 4 Medications that cause worsening of neurogenic bowel List 4 Predisposing factors for constipation π
Medications
- Antidepressants
- Anti-spasticity medications
- Anticholenergics
- Pain medications
Factors
- Decreased dietary fiber intake
- Dehydration
- Decreased mobility/activity
- Anticholerengic side effects
- Degenerative disease (Dementia, Parkinson)
- Depression
UMN vs LMN Bowel. Lesion - Muscles & Sphincter - Reflexes - Presentation - Stool - Tx ππ
Key difference is if its UMN or LMN lesion 3 marks.
In SCI, We will loss sympathetic and parasympathetic input to the colon:
- Decreased fecal movement β Fecal impaction and constipation in any injury
- Colonic peristalsis still occurs due to the activity of the intrinsic myenteric plexus
Key difference is if its UMN or LMN lesion
- Reflex defecation
- Anal sphincter tone
- Anal wink & Bulbo-anal Reflex
https://community.scireproject.com/topic/bowel/#spastic-and-flaccid-bowel
Spinal Cord Medicine Principles and Practice - 2nd Edition (2010)
Neurogenic Bowel Guidelines Sept, 2012
A 35 year old woman presents to clinic 18 months after flaccid paraplegia that resulted from an L1 burst fracture. She is wearing diapers as a bowel program. The change in bowel care technique that would most likely lead to an improvement in fecal continence would be
Schedule bowel care after breakfast and dinner daily with manual evacuation
The bowel care technique for the first several days following a spinal cord injury is most effectively accomplished with
Manual evacuation of feces as patient will be in spinal shock state.
List 3 physical exam maneuvers to assess neurological control of the rectum ππ
1. Anal wink (S2-4)
Contraction of the external anal sphincter upon stimulating skin around the anus
2. Bulbocavernosus Reflex (S2-4)
Compressing the glans penis in males or by applying pressure to the clitoris in females and observing contraction of the anal sphincter.
3 Anal tone and voluntary anal contraction (VAC)
Innervated via pudendal nerve
4. Sensation (Pin prick in S4-5)
5. Deep anal pressure (DAP)
Name 3 cutaneous reflexes that can be assessed in UMN bowel D/Os. π
- Bulbocavernosus reflex (S2-4).
- Anal wink/anocutaneous reflex (S2-4).
- Plantar response (test of UMN).
- Cremaster reflex (T12-L1-2; genitofemoral nerve).
- Abdominal reflex (Upper: T8-T10; Lower: T10-T12).
Ref: Neurology resident guide.
List 3 clinical features of classic superior mesenteric artery (SMA) syndrome List 3 predisposing factors for SMA syndrome π
Symptoms
- Bloating
- Abdominal pain
- Postprandial nausea and vomiting
Predisposing factors include
- Rapid weight loss (decrease in protective fatty layer)
- Prolonged supine position. Most common in tetraplegia.
- Spinal orthosis
Cuccurolo 4th Edition Chapter 7 SCI pg587