Pathology -- Defecatory Disorders Flashcards
(96 cards)
1
Q
2 defecatory disorders
A
Constipation
Fecal incontinence
2
Q
9 causal conditions of constipation
A
- Diet, lifestyle
- Irritable bowel syndrome
- Drugs
- Neurogenic (central or peripheral)
- Myopathic
- Metbaolic
- Pregnancy
- Obstructive lesions
- Anorectal disease
3
Q
Define fecal incontinence
A
- Varies from inadvertent soiling with liquid stool to the involuntary excretion of feces
- Insufficient voluntary control of gas or stool
- NOT a diagnosis, but a symptom
4
Q
4 causal conditions of fecal incontinence
A
- Pelvic floor intact
- Neurological conditions
- Overflow (i.e. impaction)
- Pelvic floor affected
- Acquired (i.e. traumatic birth)
- Congenital
5
Q
4 consequences of being unable to poop normally
A
- Social isolation and stigmatization
- Physical disability
- Psychological distress
- Societal costs – direct care, institutionalization, loss of productivity
6
Q
Right colon and transverse colon functions
A
Churning and mixing
7
Q
Left colon function
A
Water absorption and stool delivery
8
Q
Rectum function
A
Stool storage until socially appropriate moment, termed capacitance
9
Q
Norma capacitance of stool in rectum
A
200 - 250 mL
10
Q
Anus function
A
- Muscular cork to prevent involuntary stool loss
- Allows us to distinguish between solid and liquid stool ,flatus
11
Q
Dscribe the internal anal sphincter’s characteristics
A
Continuous with inner circular muscle
- Smooth muscle
- Involuntary control
- Resting tone
12
Q
Describe the external anal sphincter’s characteristics
A
Continuous with pelvic floor
- Skeletal muscle
- Voluntary control
13
Q
4 layers of the anus
A
- Internal anal sphincter
- External anal sphincter
- Longitudinal muscle
- Anoderm
14
Q
Define the dentate line
A
Endodern (hindgut) and ectoderm junction
15
Q
Define the anal transition zone
A
Location of transition from endoderm to ectoderm, so has transitional epithelium (cloacogenic)
16
Q
2 characteristics of the anoderm
A
- Sensate (vs. insensate rectum)
- Non-keratinized squamous epithelium
17
Q
Parasympathetic pathway functions in GIT
A
- Generally promotes GIT motility
- Role in continence/rectal capacitance
- Pelvic function
18
Q
Efferent position of parasympathetic nerves for colon
A
Cranio-caudal
19
Q
Sympathetic pathway functions in colon
A
- Slows colonic motility
- Fight or flight system
20
Q
Effect position of sympathetic pathways to colon
A
Thoraco-lumbar
21
Q
3 types of contractions in colon
A
- High amplitude propagated contractions (HAC)
- Low amplitude propagated contractions (LAC)
- Segmental contractions
22
Q
Characteristics of HAC
A
- Transport stool over long distances (5 - 6 x/day)
- Occur with waking and after meals
23
Q
Characteristics of LAC
A
- Related to meals/sleep-wake cycle (not clearly understood)
- Propagate stool short distances, but more frequently (not clearly understood)
24
Q
When is transit in the colon decreased?
A
LAC > HAC
25
When is transit in the colon normal
LAC = HAC
26
When is transit in the colon increased?
HAC \> LAC
27
4 anatomic factors to maintain continence in order of importance
* Internal anal sphincter resting tone (45%)
* External sphincter (30%)
* Hemorrhoidal plexus (10 - 15%)
* Aorectal angle/puborectalis/flap-valve
28
4 important reflex arcs relating to the colon and rectum
* Gastro-colic
* Recto-anal inhibitory reflex (RAIR)
* Recto-anal excitatory reflex (RAER)
* Bulbocavernosus reflex
29
Trigger and effect of gastro-colic reflex
Food in mouth --\> colonic motility, segmental contractions
30
Trigger and effect of recto-anal inhibitory reflex (RAIR)
Rectal distension --\> RELAXATION of INTERnAL anal sphincter
31
Trigger and effect of recto-anal excitatory reflex (RAER)
Rectal distension --\> CONTRACTION of EXTERNAL anal sphincter
32
Lowest spinal reflex and the efferent position
Bulbocavernosus reflex from S2,3,4
33
Location of CNS awareness of stool moving into rectum
Anterior cingulate and frontal gyri
34
What receptors does rectal distension stimulate?
Pressure receptors in rectum and pelvic side wall
35
Purpose of RAIR in normal defecation
"Sampling" of contents (air? solid?)
36
Purpose of RAER in normal defecation
Prevent involuntary loss
37
If defecation is not appropriate at the time that stool enters the rectum, what is the body's response?
* Voluntary contraction of EAS
* Rectal accomodation (capacitance and compliance)
38
4 events if the decision to defecate is made
* Valsalva maneauver (increase abdominal pressure, glottic closure)
* Puborectal muscle RELAXATION
* EAS relaxation
* Emptying of rectal contents
39
Effect of puborectal muscle relaxation
Opens up anorectal angle and causes pelvic floor descent
40
5 pro-defecatory stimuli
* Exercise
* Distension (bulky stools, fiber)
* Waking up
* Eating
* Drugs (laxatives)
41
Why is exercise a pro-defecatory stimulus?
Stimulates HAC
42
Rome II criteria for adult constipation
**Two or more** of the following for **at least 12 weeks** (no necessarily consecutively) in the **preceding 12 months**:
* Straining during \>25% of bowel movements
* Lumpy or hard stools for \>25% of bowel movements
* Sensation of incomplete evacuation for \>25% of bowel movements
* Sensation of anorectal blockage for \>25% of bowel movements
* Manual maneuvers to facilitate \>25% of bowel movements (i.e. digital evacuation or support of the pelvic floor)
* \<3 bowel movements per week
* Loos stool not present and insufficient criteria for IBS
43
Rome II criteria for constipation in infants and children
* Pebble-like, hard stools for a majority of bowel movements for at least 2 weeks
* Firm stool less than or equal to 2 times per week for at least 2 weeks
* No evidence of structural, endocrine, or metabolic disease
44
Describe the prevalence of constipation in North America and the groups of people affected by it
NA prevalence ~15%
* Women \>\> men (3:1)
* Nonwhites \> whites
45
Reasons why women experience constipation more often than men
* Longer coloncs, slower transit (36h vs. 29h)
* Pregnancy can exacerbate
46
7 risk factors for constipation
* Increasing age
* Low-fiber, Western-style diet
* Decreased physical activity
* Low income, socio-economic status
* Limited education
* History of sexual abuse
* Depression
47
What must constipation be dinstinguished from?
Obstructed defecation syndrome (i.e. rectal prolapse, non-relaxing puborectalis, etc...)
48
Number one cause for constipation
Lifestyle neglect
49
Example of an endocrine cause for constipation
Hypothyroidism
50
Examples of medications that can cause constipation
* Narcotics
* Anti-cholinergics
* Anti-psychotics
51
Examples of neurogenic causes of constipation
Central vs. peripheral; i.e. slow-transit constipation, Chagas' disease)
52
Examples of psychological causes of constipation
Depression and anorexia
53
4 treatment principles of constipation
* Seek to identify the underlying cause
* Rule out mechanical obstruction -- combination of clinical history and/or imaging
* Strongly consider a full colonoscopy to rule out neoplasm
* In younger patients, lifestyle neglect is #1 cause -- can proceed with dietary changes +/- adjuncts
54
What is the number one reason for admittance to a nursing home?
Recal incontinence
55
Describe the groups of people affected by fecal incontinence and the prevalence
* 2 - 18% of population affected
* 50% of nursing home residents
56
3 things that are important to define in the setting of fecal incontinence
* The cause of the incontinence (establish the diagnosis)
* Degree of incontinence
* Degree to which the patient is affected (impact)
57
6 examples of "pseudo"-incontinence that must be ruled out if fecal incontinence is suspected
* Urgency and stool loss from poor rectal compliance (IBD)
* Overflow incontinences from stool impaction/ severe constipation
* Poor hygiene
* Anorectal STDs (gonorrhoea, chlamydia)
* Prolapse (rectum and hemorrhoids)
* Anorectal neoplasms
58
5 Determinants of continence
* Intact neurologic function
* Anal sphincters
* Proper function of pelvic floor musculature
* Stool consistency and volume
* Rectal compliance
59
4 neurological causes of fecal incontinence
* Spinal cord injury
* Severe diabetes
* Dementia
* Defective RAIR
60
2 ways the anal sphincters can be affected to lead to fecal incontinence
Trauma and rectal prolapse
61
An example of how imporper function of pelvic floor musculature can lead to fecal incontinence
Prudendal nerve injury
62
2 examples of fecal incontinence related to stool consistency and volume
Fecalomas and diarrhea
63
2 examples of defective rectal compliance that can lead to fecal incontinence
Neoplasms and inflammatory conditions
64
Number one cause of fecal incontinence
Obstetric
65
3 risk factors for obstetric-related fecal incontinence
* Forceps
* Episiotomies
* 1st baby
66
3 obstetric events that can lead to pudendal nerve injury
* Prolonged straining (2nd stage of labor)
* Forceps
* Big babies
67
Frequency of anal tears in the obstetric setting
0.6 - 9% and may breakdown/weaken with time even post-repair
68
4 categories of causes for fecal incontinence
* Obstetric
* Iatrogenic
* Congenital malformations
* Rectal prolapse
69
3 iatrogenic causes of fecal incontinence
* Fistulotomy
* Sphincterotomy
* Radiation proctitis
70
3 congenital causes of fecal incontinence
* Spina bifida
* Myelomeningocele
* Imperforate anus
71
3 steps in evaluation of a patient with fecal incontinence
* Detailed history and physical exam
* Look for scarring, trauma from birthing, excoriation/skin changes from chronic soiling, patulous anus, associated conditions
* Digital rectal exam for fecalomas, anal sphincter condition, anal squeeze
72
3 specific aspects of the detailed history and physical exam for patients with fecal incontinence
* Stool diary
* Incontinence scale
* Rule out diarrheal states and pseudo-incontinence
73
4 diagnostic tools for a patient with fecal incontinence
* Full colonoscopy
* Endoanal ultrasound
* Pudendal nerve terminal motor latency (PNTML)
* Anal manometry
74
Purpose of full colonoscopy for fecal incontinence patients
Rule out other lesions
75
Best test to assess fecal incontinence
Endoanal ultrasound
76
Aspects evaluated by endoanal ultrasound
* Internal and external sphincters
* Distance between the vaginal orifice, size of perineal body, anal musculature
77
What is defined as an abnormal finding by endoanal ultrasound?
Perineal body thickness of less than 10 mm
78
Purpose of PNTML for fecal incontinence patient
Checks the pudendal nerve for injury
79
Normal range of pressure measured by anal manometry
40 - 70 mm Hg
80
What does anal manometry check?
RAIR and rectal compliance
81
2 steps of treatment for fecal incontinence
* Estbliash the diagnosis and treat the underlying condition
* Medical management
82
4 types of medical treatments for fecal incontinence
* Meds to normalize stool consistency
* Conspitating agents
* Biofeedback
* Injectable sphincter-bulking agents (silicone-based)
83
2 ways to normalize stool consistency
* Bulking (by psyllium, for example)
* Treatment of diarrhea and constipation (scheduled disimpactions if necessary)
84
3 constipating agents
* Loperamide (imodium)
* Lomotil
* Codeine
85
Describe biofeedback
Visual and auditory feedback for pelvic physical therapy
86
Benefits of biofeedback for fecal incontinence patients
* 44% achieve complete continence
* 76% achieve improved continence
by 3 months
87
5 surgical options for fecal incontinence
* Overlapping sphincteroplasty
* Artificial bowel sphincter
* Sacral nerve stimulatory (SNS)
* Antegrade enema
* Permanent colostomy
88
How does an antegrade enema access the rectum?
By cecostomy button or appendix
89
Benefit of antegrade enema
Large volume (3 - 4 saline enema) can clean colon for up to 48 hours
90
When is permanent colostomy used?
When many modalities have failed
91
Define overlapping sphincteroplasty
Surgical repair of damaged sphincters to reconstitue the anatomy
92
Benefit of overlapping sphincteroplasty
* Good initial results
* ~50% remain continent to both solid and liquid stool at 5 years
* Can repeat the surgery to "re-tighten" muscles
93
Initial purpose of sacral nerve stimulation
Treatment for urinary incontinence
94
Explain how sacral nerve stimulation works
Mechanism is unclear, but overal effect is increased resting tone by placing the stimulator by the 3rd sacral n. root
95
Describe the artificial bowel sphincter
If the anal muscles are destroyed, an aritificial sphincter can be recreated with an inflatable cuff, with the pump place in scrotum/labium
96
Problem with artificial bowel sphincter
High infection rates
