Disordered Defecation Flashcards
1
Q
Defecation and Micturition Similarities
A
Storage (accommodation)
Outlet (internal and external sphincters)
Pelvic floor muscles (levator ahi muscle, puborectalis sling, innervated by pudendal nerve)
Innervation
2
Q
Storage: Accommodation
A
Waste stored at low-pressure
Low pressure prevent reflux
3
Q
Internal Sphincter
A
Involuntary muscle
Tonically contracted to prevent leakage
Automatically relaxes as filling occurs
4
Q
External Sphincter
A
Striated muscle Consciously controlled Not maximally contracted Contracts more when "time not right" Overrides internal sphincter
5
Q
Pelvic Floor Muscles
A
Supports pelvic organs
Levator ani muscle and puborectalis sling
Voluntary control
Wrap around urethra, vagina, rectum as pass through pelvic floor
6
Q
Peripheral Nervous System: Sympathetic Innervation
A
Continence nerves T10-L2
- gut motility and secretion
Relaxes bladder
Tightens internal sphincter
7
Q
Peripheral Nervous System: Parasympathetic Innervation
A
Continence nerves S2-S4
+ gut motility and secretion
Contracts bladder
8
Q
Central Nervous System: Pons
A
Unconscious
Initiates bladder contractions
Instructs internal sphincter to relax
9
Q
Central Nervous System: Frontal Lobe
A
“Social Continence”
Interrupts message from pons
If time is right, sphincter relaxes to allow urine/BM passage
10
Q
Factors Contributing to Bowel Control Issues
A
Antibiotics Enteral feedings Hypoproteinamia Crohn's Chronic Ulcerative Colitis Bowel obstruction Fecal impaction Radiation therapy Chemotherapy
11
Q
Mechanisms for Bowel Continence
A
Transit time Stool consistency Stool volume Awareness of filling Intact pelvic floor and sphincter muscles Rectal capacity and compliance
12
Q
Intake/Output Volume
A
Oral fluid intake: 1-2 L/day
Small intestine secretions: 6-7 L/day
Volume at ileocecal valve: 1-1.5 L/day
Volume in rectum: 50-100 cc/day
Small intestine absorbs 7-9 L/day
Colon absorbs 1 L/day
13
Q
Mucosal Layer
A
Secretes mucus to lubricate mucosal lining = forward movement of food bolus and prevention of abrasions
14
Q
Villi
A
+ absorptive surface
15
Q
Transit, Consistency, Volume Factors
A
Ileosecal valve Structures intact Absorption Peristalsis Segmentation and austral contractions Diet (fiber)
16
Q
Ileocecal Valve
A
Gradual release of contents into colon
Prevents backward movement of stool
17
Q
Segmentation
A
Mixing action
18
Q
Haustral Contractions
A
Pushes stool forward
19
Q
Myenteric plexus aka Auerbach’s plexus
A
Regulates colon motility
Detects bowel distention and luminal irritants
Between muscles in colon wall
Intrinsic (enteric) NS
20
Q
Submucosal Innervation: Meissner’s plexus
A
Detects bowel distention and luminal irritants
Intrinsic (enteric) NS
21
Q
Increased Rectal Capacity
A
2nd to chronic delayed defecation, - sensitivity to distention, ineffective contractility
22
Q
Decreased Rectal Capacity/Compliance
A
Experience normal sensation and muscle function
Extreme urgency
Associate w/ damage to mucosal surface (IBD, radiated bowel)
23
Q
Awareness of Rectal Filling
A
Normal volume delivered in normal period of time
En Masse contractions move stool forward (1 - 2x/day)
Voluntary
Conscious control in anal canal (transition zone)
24
Q
Anal Canal
A
Columnar epithelium above Dentate Line
Squamous epithelium below Dentate Line
Begin to detect sensation in Transition Zone
25
Rectoanal Inhibitory Reflex
Rectum distends
| Internal anal sphincter (IAS) relaxes automatically (reflexively)
26
Sampling Reflex
With internal sphincter relaxed, rectal contents come into contact w/ anal canal
Squamous epithelial cells discriminate btwn flatus and stool, liquid and solid
27
Anal Wink
Reflex
Indicates pudenal nerve intact
Stroke perianal skin
External sphincter contracts = contraction of muscle around anus
28
Forces Influencing Defecation
Propulsive: val salva, gravity, peristalsis
Resistive: External compression, rectal compliance, external sphincter, puborectalis muscle
29
Upper Urinary Tract
Kidney: 60 cc/hr urine production, + w/ age
Renal pelvis: store 15-30 cc urine
Ureter: peristalsis moves 5-15 cc urine to bladder
30
Lower Urinary Tract
Bladder: detrusor, body, neck, base
Detrusor compliance: stores 300-600 cc, - compliance = + filling pressure = urine reflux
Urothelium: Transitional epithelium
Urethra
31
Urethra
Collapsible
Proximal urethra is sphincter mechanism in males
Entire urethra functions as female sphincter
Distal 2/3 fused to vaginal wall
Coaptation: mucus +surface tension and adherence
Voluntary control of sphincter and pelvic floor
Innervated by Pudendal from S2-S4
32
Bladder Filling and Storage
Detrusor relaxed / Sphincter contracted
| Controlled by Sympathetic Nervous System (T10-L2)
33
Bladder Emptying Phase
Controlled by Parasympathetic (S2-S4)
Detrusor extends
Signal sent to micturition center (S2-S4)
Pons replies to contract bladder (empty)
Frontal lobe interrupts Pons if time not right to void
If time right, sphincter relaxes
34
Age-Related Bladder Control
```
- bladder capacity
+ urine output at night
- sensory awareness of filling
- urinary flow rate
- urethral closing pressure and length 2nd to - estrogen
- ability to delay voiding
```
35
Bowel Diary
Frequency, volume, consistency of continent and incontinent stools
Keep 1-2 weeks
36
Physical exam
Tighten anus and bear down: note weakness, nerve damage, prolapse, sphincter disruption
Digital exam: tumor, impaction, prolapse, hemorrhoids, musculature exam
37
Anorectal Manometry
Measures pressures w/i anal canal during rest, contraction, relaxation
Localizes and quantifies sphincter deficits
Determines length of anal canal
Provides estimate of sampling reflex, rectal sensation/capacity/compliance
Mean and maximal resting pressure
Mean and maximal squeeze pressure
38
Mean and Maximal Resting Pressure
Reflects status of function of internal anal sphincter
39
Mean and Maximal Squeeze Pressure
Reflects status of function of external anal sphincter
40
Anal EMG
Useful when evaluating anal incontinence 2nd to disruption of external anal sphincter mechanism
Benefit in locating severed ends of sphincter muscle
PAINFUL
41
Pudendal Nerve Terminal Motor Latency (PNTML)
Checks for nerve damage to EAS (pudendal neuropathy)
+PNTML (2.2+ msec) = - conduction in terminal part of pudendal nerve to the EAS
Assesses - rectal filling sensation
May influence prognosis after surgical corrections of sphincter defects
42
Endoanal Ultrasonography (EAUS)
Probe size of finger inserted into anal canal
Probe rotates 360 to provide image of IAS and EAS
IDs defects, asymmetry, thickness of sphincter muscle
Simple, painless, accurate, repeatable
Follow-up after surgical correction of incontinence
- need for EMG 2nd to correlation w/ absent electromyographic activity
43
Rectal Compliance Study
Ability of rectum to distend or stretch and store stool at low pressure
44
Defecography
Evaluates function of anorectal unit during BM
| IDs pelvic floor dysfunction affecting stool evacuation (prolapse, rectocele, non-relaxing puborectalis)
45
Barium Enema
View structures of colon
46
Motility Studies
Follow contrast material progression through intestinal tract
47
Bristol Stool Scale: Type 1
Stools in separate, hard lumps
Nut-like
Stool remains in colon longest amount of time
Sign of constipation
48
Bristol Stool Scale: Type 2
Sausage-like stool
Lumpy
Indicate toxic constipation and need for intestinal cleaning
49
Bristol Stool Scale: Type 3
Normal
Sausage-like
Cracks is surface
50
Bristol Stool Scale: Type 4
Normal
Smooth and soft
Form of sausage or snake
51
Bristol Stool Scale: Type 5
```
Soft blobs w/ clear-cut edges
Easily pass through digestive system
Soft diarrhea
Possible risk of bowel disease
Indicates toxic and need for regular intestinal cleaning
```
52
Bristol Stool Scale: Type 6
Fluffy pieces w/ ragged edges
Mushy stools
Indicate diarrhea
Indicates toxic and need regular intestinal cleaning
53
Bristol Stool Scale: Type 7
Mostly liquid w/ 0 solid pieces
Passed quickly through colon
Indicative of severe diarrhea as result of viral or bacterial infection
See doctor ASAP
54
Bristol Stool Scale: Type 8
Mucous-like consistency w/ bubbles and foul odor
Unsafe amount of alcohol/drugs
Not originally part of scale
55
Intrinsic Innervation
Inside bowel
Meissner's cells (in submucosal layer of bowel)
Auerbach's plexus (in mucosal layer of bowel)
Regulates colonic motility
Triggered by colonic distention and intraluminal irritants
Not affected by SCI
Intrinsic (enteric) NS
56
Extrinsic Innervation
Outside bowel
Innervated by Autonomic Nervous System
Involuntary
Sympathetic or Parasympathetic
57
Sympathetic pathway
Arise from T10-L2
- intestinal motility and secretion
Loose stools occur if innervation disrupted
58
Parasympathetic pathway
Arise from S2-S4
+ peristalsis and intestinal secretion in L colon
Contributes to reflex activity w/i distal colon
Severe constipation occurs if sacral cord lesion occurs, but may respond to stimulant program because Intrinsic system is intact
59
External Anal Sphincter (EAS)
Bilateral motor innervation: Contains smooth (involuntary) and striated (voluntary) muscle
60
Smooth Muscle of EAS
```
Keeps sphincter in resting state of tonic contraction
Involuntary control (smooth muscle) by intrinsic nervous system
```
61
Striated Muscle of EAS
Voluntary control to delay defecation
| Primarily innervated by Somatic nerve through branches of pudendal nerve exiting at S2-S4
62
Pudendal Nerve Tests
```
Anal wink: Contraction of EAS when perianal skin stroked at 3 or 9 o'clock
Bulbocavernous relex (BCR): Contraction of EAS when glans penis squeezed or clitoris is tapped
Positive contraction = innervation of striated muscles of pelvic floor
```
63
Internal Anal Sphincter (IAS): Structure
Smooth circular muscle 3cm in length
| Encircles anorectal junction and proximal 2cm of anal canal
64
Internal Anal Sphincter (IAS): Innervation
Sympathetic nervous system
Tonically contracted to maintain anal canal in closed position
Involuntary control
65
Internal Anal Sphincter (IAS): Autonomic Reflexes
Important for continence
Rectoanal inhibitory reflex: relaxation of IAS in response to rectal distention
Sampling reflex: sensory receptors in anal canal "sample" bowel contents to determine is gas, liquid, or solid stool
66
Acute Diarrhea
Lasts -4wks
Self-limiting in non-hospitalized pt
Symptom management
Clinical eval after 7 days if pt immunosuppressed, elderly, or deteriorating
Caused by viral, protozoal, or bacterial infection
67
Manifestations of Inflammatory Diarrhea
Stool w/ blood, leukocytes, pus or mucus
Fever over 38.5
Prostration
68
Risk Factors or Inflammatory Diarrhea
```
Travel
Unusual food/fluid
Contaminated food/fluid
Exposure to sick
Anal sexual intercourse
```
69
Secretory Diarrhea
Volume of H2O and electrolytes secreted into bowel lumen overwhelms absorptive capacity
Caused by infectious agent, malabsorbed substances, malignant tumors, prostaglandins produced 2nd to colitis
70
Manifestations of Secretory Diarrhea
```
Large volume of stool (+1 L/day)
Neutral stool pH
0 reduction in stool when fasting
Hyponatremia 2nd to excessive Na loss
Stool osmotic gap of less than 50 mOsm/kg
```
71
Absorptive Diarrhea (Osmotic)
Inadequate or reduced absorption by bowel
72
Absorptive Diarrhea (Osmotic): Causes
Alterations in intestinal mucosa
Conditions producing hyperosmolar substances into lumen of bowel that block transport of H2O and electrolytes into epithelium
Hyperosmolar substances in lumen = osmotic force that pulls H2O and electrolytes INTO bowel lumen
73
Examples of Absorptive Disorders
Alteration in mucosal surface: malnutrition, NPO, hypoproteinemia, +bowel reduction, villi atrophy, IBD
74
Causes of Osmotic Diarrhea
Intolerance to sugars
| Fat malabsorption syndromes
75
Manifestations of Absorptive Diarrhea
```
- volume stool (-L/day)
Acidic stool pH
K loss exceeds Na loss = hypokalemia
Stool output volume - by fasting 2nd to malabsorbed substance eliminated
Stool osmolality gap + 50 mOsm/kg
```
76
Motility Disorders
```
+ motility = - contact time btwn contents and mucosa
IBD
IBS
Rapid gastric emptying
Infectious diarrheas
```
77
Diminished Motility
Causes severe constipation, impaction, cramping
Fluid secreted into lumen behind bolus = liquid stool seeps around obstruction
Stagnation of stool = bacterial growth
78
Examples of Mixed Diarrhea Disorders
```
Laxative abuse (+ motility and - absorption)
Infectious diarrhea 2nd to C.diff (toxins cause secretory diarrhea and alter absorptive function)
AIDS-related (infectious and malabsorptive, 4-6 L of stool)
```
79
Rome II Criteria for Constipation
2+ symptoms for 12 weeks during 12 months in pt w/o IBS
Straining
Lumpy or hard stool
Sensation of incomplete evacuation
Manual maneuvers to facilitate evacuation
(All more than 25% of time)
80
Risk Factors for Constipation
```
Female
Nonwhite
Low socioeconomic status
+ age
- calorie, - fiber diet
Sedentary
Comorbid medical conditions
Neuromuscular disorders
Strain/sprain in sacroiliac region
SCI
Herpes zoster
Psychotic disorder
Opioid analgesics
```
81
Normal Transit Constipation
Most common type of constipation
Colon function is normal
Extrinsic contributing factors
82
Inadequate Fiber or Fluid
- stool volume = hard, small caliber stools
| - peristaltic activity = + contact w/ mucosa = + H2O absorption
83
Decreased Activity Level
- gut motility
| - pelvic floor muscle tone
84
Poor Toileting Behavior
Suppression of urge/delay in defecation = dehydrated stool
85
Constipating Medications
```
Antocholinergics
CV meds
Anticonvulsants/antiparkinsons meds
Narcotics
Vinca alkaloids
Cation containing meds (antacids, Ca, Fe)
Nonsteroidal anti-inflammatory meds
```
86
Slow-Transit Constipation
```
Colonic inertia
- in frequency (1x/week or less)
Bloating, ABD discomfort
Common in young women at puberty
- peristaltic contractions = dehydrated stool
+ pressure in rectum and sigmoid
```
87
Etiologic Factors for Slow-Transit Constipation
```
Neurologic lesion
Condition damaging autonomic nervous system
Low SCI
Parkinson's
MS
Cholecystokinin (CCK)
```
88
Obstructed Defecation Syndromes
```
Inability to eliminate stool even w/ soft consistency
Difficulty initiating defecation
Failure to achieve complete evacuation
Feeling of blockage
Retained stool
```
89
Pelvic Floor Dyssynergia
Cause of obstructed defecation syndrome
Failure to relax pelvic floor muscles
Inadvertent contraction of anal sphincter
tx: pelvic muscle re-education w/ biofeedback
90
Pelvic Floor Dyssynergia: Diagnosis
2+ of following:
Anorectal manometry shows + in anal pressure
Inability to expel balloon in 3 min
+ colonic transit time (retain 5+ radiopaque markers after 120 hours)
Inability to expel barium during defecography
91
Rectocele
Common cause of obstructed defecation
Herniation of anterior rectal wall into posterior vagina
Straining pushes stool into vaginal pouch
Risks: vag delivery, hysterectomy, postmenopausal, connective tissue disorders, chronic straining
tx: pessary or surgical repair
92
Rectal Prolapse
Cause of obstructed defecation
Rectal mucosa protrudes from anus
Assess pt bearing down while lying/standing
tx: surgical repair to prevent innervation problems
93
Irritable Bowel Syndrome (IBS)
ABD pain, bloating, distention, incomplete emptying, changes in stool freq/consistency
Pain relieved w/ defecation
Constipation-predominant, diarrhea-predominant or intermittent
Affects women commonly
Appears in late adolescence
Diagnosis by exclusion
94
Rome II Diagnosis of IBS
```
3 months continuous/recurrent
ABD pain or discomfort:
* relieved by defecation
* associated w/ change in stool freq/consistency
2+ at least 25% of time
* altered stool freq/form/passage
* passage of mucus
* bloating
```
95
IBS Treatment
```
Address predominant bowel symptom
Control dietary factors
Provide education
Symptom diary
Cognitive behavior therapies
0 pharmacologic regulation of serotonin in GI tract
```
96
Complete Fecal Incontinence
Formed or liquid stool/gas
| Damage to external anal sphincter or neurologic lesion
97
Partial Fecal Incontinence
Leakage of gas and liquid stool only
| Common if internal anal sphincter damaged
98
Seepage and Soiling
Leakage of small amounts of stool in pt who is continent
| Compromised sensory awareness or rectal distention
99
Encopresis
Fecal soiling in peds (4+ in age)
Occurs w/ functional constipation
No organic or anatomic lesion
2nd to fear, stress, diet, distraction
100
Retentive Encopresis
```
Associate w/ constipation
May develop megacolon
Overflow stooling
Formed, ribbon-like stool or loose, odorous, and thin
Painful bowel movements
Several accidents/day
```
101
Non-retentive Encopresis
0 evidence of constipation
Stress related
Primary: pt is 4+ and never been continent (organic or stressed)
Secondary: bowel control for 1 yr before incontinence (psychologic issues)
102
BRAT Diet
Bananas, Rice, Applesauce, Tapioca
+ stool consistency
- H2O in stool
Also use yogurt, cheese, marshmallows, wheat, pectin-containing fruits (apples)
103
Bulking Agents
Psyllium
Guar gum
Thicken stool by absorbing fluid and slow intestinal transit time
104
Constipation Treatment
```
- peristaltic inhibitors
+ fluid and fiber
25-30 g fiber/day
Introduce slowly to prevent distention/gas
30mL/kg fluid
```
105
Sphincteroplasty
If sphincter disrupted
Dissect back to healthy muscle and ends overlapped to complete ring
Common following OB trauma
106
Graciloplasty
Compensates for weak sphincter
Overlapped ends of sphincter gracilis muscle mobilized from leg attachment
Wrapped around anus
Limitations: inability to voluntarily contract muscle and inability to provide sustained resistance
107
Dynamic Graciloplasty
Electrical stimulation converts fast-twitch muscle fibers to slow-twitch
+ duration of contraction
Electrical stimulus interrupted w/ hand-held device when time to defecate
108
Artificial Anal Sphincter
Cuff placed around anal canal to serve as anal sphincter
Reservoir implanted into groin or lower and
Pump implanted into into scrotum or labia
Cuff filled w/ fluid from reservoir to compress anal canal
Deflate cuff to defecate
+ need for revision = reserved for refractory incontinence
Cuff left deflated for 6-8 weeks for healing
109
Adapt to loss of sensory awareness or sphincter control
Stimulated defecation program
Antegrade continence enema (ACE) procedure
Colostomy
Stool containment and skin protection (absorptive products,
anal plug)
External collection (pouches, internal drainage system)
110
Peds age for continence
Toilet training btwn 24 - 30 months
Bowel and bladder control when awake at 3 yrs
Bowel continence at age 4
111
Neurologic Readinenss Criteria
Reflex sphincter control (begins at 9 months)
| Myelinization of pyramidal tracts (complete btwn 12-18 mo)
112
Psychological Readiness Criteria
Motor: able to walk to WC, sit on toilet, take off clothes
Cognitive: Communicate urge
Instructional: follow 1-2 step commands
Misc: desire, positive relationship with caregivers
113
Imperforate Anus
Absence of visible opening
Distal bowel ends above or below levator ahi pelvic muscle
Temp diverting colostomy
Pull through surgery at 18-20lbs (12-15 mo)
Fecal incontinence common after surgery
114
Hirschsprung's Disease
0 ganglion cells in colon/rectum = 0 peristalsis
Always involves rectum may go retrograde into colon
Bouts of obstruction and impaction
tx: remove aganglionic segment and create colostomy when baby is 12-15 mo/20 lbs
Fecal incontinence common after surgery
115
Biofeedback
When nerve pathway intact but unable to contract adequately
116
Stimulated Defecation Program
Decreased sensory awareness in chronic rectal distention or neurogenic bowel
117
Complete Incontinence
External sphincter
118
Partial Incontinence
Internal sphincter
119
Seepage and Soiling
Leakage btwn BMs in continent patient
Smearing
- sensory awareness
Hemorrhoid or prolapse
120
Autonomic and Enteric Nervous System
Responsible for internal anal sphincter
121
Neurologic Lesions
Alter sensory awareness of rectal filling
Diabetic neuropathy, MS, SCI, Myelomeningocele
tx: Maintain solid stool
122
Pudendal Nerve Damage
Difficult deliveries, large babies, forceps, chronic straining
tx: Maintain formed stool, biofeedback to + sensory awareness
123
Cognitive Impairment
Pathways intact but - interpretation of message
ex: dementia
tx: Stimulated defecation program w/ suppositories
124
Chronic Rectal Distention
Chronic constipation = distended rectum w/o urge to defecate
May cause megarectum
tx: Disimpaction, colonic cleaning, stimulated defecation program w/ suppositories
125
Anorectal Lesions
Hemorrhoids, rectal prolapse
Fail to sense slight distention
IAS relaxes but EAS doesn't respond
tx: Bulking agents, biofeedback to + awareness
126
Spinal Cord Injury
Unable to contract EAS, altered sensation of rectal filling
IAS and rectoanal inhibitory reflex intact (enteric NS)
tx: maintain soft/formed stool, stimulated defecation program
127
Pudendal Neuropathy
EAS (somatic NS) affected = reduced ability to delay BM
| tx: maintain formed stool, stimulated defecation program, artificial sphincter
128
Increased Capacity/Compliance
Chronic delays in defecation (megarectum) = reduced sensitivity to distention
tx: disimpaction, colonic cleansing, maintain soft/formed stool, stimulated defecation program
129
Reduced Capacity/Compliance
Fibrotic rectal unit
Inflammatory process (IBD, gastroenteritis) or fibrotic changes (radiation, ischemic injury)
Unable to relax rectal wall to accommodate stool
tx: management of underlying disease, fecal diversion
