Constipation, SBO, Toxic Megacolon Geralds Flashcards
Definition of constipation
A group of syndromes w/similar findings that include:
- Unsatisfactory defecation (infrequent stools)
- Difficult stool passage
- OR both
What are characteristics of constipation?
- Less than 3 BMs per week
- Hard stools
- Excessive straining
- Prolonged time spent on commode
- Sense of incomplete evacuation of stool
- Abdominal discomfort or bloating
Epidemiology of constipation
- More in children, elderly
- Females 2:1
- Nonwhites
Primary etiologies of constipation
- Slow colonic transit times (normal is 35 hrs, slow is 72+ hrs)
- Pelvic floor/anal sphincter dysfunction
- Functional (normal transit time and sphincter function yet problems w/bloating, hard stools, pain)
Secondary etiologies of constipation
- IBS
- Endocrine
- Metabolic
- Mechanical
- Pregnancy
- Meds
- Neuro disorders
Meds that can cause constipation
- Anticholinergics (antidepressants, narcotics, antipsychotics)
- Antacids
- CCBs
Pathophys of fecal production
- Food in stomach
- Ileocecal valve relaxes
- Chyme enters colon
- Peristalsis moves chyme through colon
- Na is absorbed from chyme in exchange for K and bicarb
- Water follows
- Chyme is converted into feces
Meals reach colon in:
4 hrs
Meals reach pelvic colon in:
8 hrs
What initiates the defecation reflex?
Rectal distension
Risks of constipation
- Age, disability
- Dehydration
- Hypothyroid
- Hypokalemia
- Hypercalcemia
What are red flags of constipation that you should look out for?
- New onset over 50
- Hematochezia/melena
- Unintentional wt loss
- Night sweats, fever
- Anemia
- Neuro defects
How is constipation diagnosed?
ROME III Criteria (at least 2 for 12 wks in the past 6 months)
- Less than 3 stools/wk
- Straining at least 1/4 of time
- Hard stools
- Manual assist
- Sense of incomplete evacuation
How do loose stools present in constipation?
- RARELY seen w/o use of laxatives
- EXCEPT w/fecal impaction
How is stool classified?
Bristol Stool Chart
- Types 1-2 hard/lumpy
- Types 3-4 normal
- Types 5-7 liquidy
How can colonic transit time be measured?
- SITZMARK marker ingested
- Plain films taken 5 days later
- Retention 20+% is slow transit
- Markers in distal colon/rectum suggest defecation disorder
What diagnostic procedures are useful in defecation problems?
- Balloon expulsion
- Defecography (proctogram) using barium paste
- Anorectal manometry w/a rectal catheter
What is used to treat bloating, discomfort, straining?
Osmotic agents
What is used to treat hemorrhoids/fissures?
Stool softeners to make defecation easier
Non-pharm treatment of constipation
If no known secondary cause, then:
- Regular exercise
- Increased fluid intake
- Bowel habit training
Pharmacologic treatment of constipation
- Bulking agents
- Stimulant laxatives
- Enemas
What is important to remember when using bulking agents?
Use adequate amount of liquids
What agents are used for pre-procedural stool evacuation?
- PEG 4
- Mag Citrate
Major complication of constipation
Fecal impactions (can lead to large bowel obstruction, partial or complete)
Treatment of fecal impaction
Manual disimpaction
Define acute paralytic ileus
Neuro failure or loss of peristalsis in the intestine
*Not a true obstruction
What bowel obstruction is common in hospitalized pts?
Acute paralytic ileus
Causes of acute paralytic ileus
- Intra abdominal process (surgery, peritonitis)
- Severe illness (PNA, electrolytes abnormality)
- Meds (opioids, anticholinergic, phenothiazines)
What order does GI motility normalize post-op and when?
- Small bowel (hours)
- Stomach (24-48 hrs)
- Colon (48-72 hrs)
Post op paralytic ileus risk is reduced by:
- Use of pt controlled anesthesia
- Avoidance of IV opioids
- Early ambulation
- Gum chewing
- Clear liquid diet
Pain with a paralytic ileus may indicate:
Small bowel mechanical obstruction (may present as ileus first)
Treatment of paralytic ileus
- Restrict oral intake
- NG tubes to LWS if N/V from ileus refractory
- IV fluids/parenteral nutrition
- Meds to reverse mu-opioid receptor antagonist
What is Ogilvie syndrome?
- Complication of paralytic ileus
- Colonic pseudo obstruction
- Disruption of intestinal motor function leading to massive dilation in absence of mechanical obstruction
- NOT toxic megacolon
What is a complication of paralytic ileus?
Ogilvie syndrome
Who is affected by Ogilvie syndrome?
- 60+ yo
- Men
- Hospitalized
- Post op CABG/THR
- Meds
What must be excluded when evaluating for Ogilvie syndrome?
Toxic megacolon d/t C diff infection (use stool test in pts w/abdominal distension)
Treatment of Ogilvie syndrome
- Treat underlying disorder
- Give abx if sepsis suspected
- Conservative management for 24-48 hrs is preferred (if cecal diameter less than 12 cm)
- Keep NPO
- IV hydration
What pharm treatments can be given for Ogilvie syndrome?
- Neostigmine
- Antimotility agents
Types of small bowel obstruction
- Partial (low grade)
- Complete (high grade)
Causes of small bowel obstruction
- Adhesions (74% cases)
- Malignancy
- Hernia
- IBD
- Misc
If a patient cannot pass gas, what is suspected?
Small bowel obstruction
Treatment of small bowel obstruction
- Surgery indicated if peritonitis, bowel ischemia
- Close monitoring
What may be more effective for bowel decompression?
Transnasal ileus tube advanced endoscopically may be more effective than regular NG tube
Define toxic megacolon
- Life threatening complication of other intestinal conditions
- Widening (dilation) of large intestine w/in 1-3 days
Causes of toxic megacolon
IBD (NOT IBS)
- Crohn’s, UC, C diff diarrhea
- Toxic refers to inflamm/infection/acute
Treatment of toxic megacolon
- Fluids and electrolytes (not usually enough to reverse condition, used to prevent dehydration and shock)
- Most cases need surgery
