lecture 66 Flashcards
constipation (scott)
primary causes of chronic constipation
normal transit functional symptomatic (most common)
slow transition
evacuation disorder
secondary causes of chronic constipation
medications
obstruction (cancer, stricture)
metabolic (hypothyroid, hypercalcemia)
neurological (parkinsonism, MS)
systemic (scleroderma, amyloidosis)
psychiatric (depression, eating disorders)
medications that cause constipation
Analgesics (opioids and NSAIDs)
antacids (aluminum, calcium)
agents with strong anticholinergic properties (antihistamines, antimuscarinics, and amitriptyline)
iron preparations
diueretics
chronic use of stimulant laxatives (mixed evidence, unlikely if normal dose is used)
normal physiology of defectation
sensory perception of stool
rectal distension
contract diaphragm, abdomen, and rectal muscles
relax EAS (decrease LES pressure)
relax puborectallis muscle
dyssynergic defecation
prolonged colonic transit time
discoordination of abdominal, rectonanal, and pelvic floor muscles
rectal hyposensitivity
paradoxical increase in sphincter pressure
under 20% relaxation of resting and sphincter pressure
inadequate abdomino-rectal propulsive forces
acute constipation presentation
a noticeable change in normal BM pattern (less than 3 per week)
other features - stools are dry and hard; BM is painful and stools are difficult to pass; feelings that bowels have not been fully emptied
acute treatment
based on relief being seen in
follow up in 1-2 days and check stool frequency, episodes of diarrhea, dietary changes, and SE from meds
acute relief in 1 hour
use enema (saline, tap water, or soap suds)
bisacodyl or glycerin suppository
acute relief in 3 to 6 hours
citrate of magnesia
larger doses of PEG (also used for GI preps)
acute relief in 24 hours
bisacodyl tablets
senna tablets
acute relief in 48 hours
milk of magnesia
PEG (miralax)
chronic presentation
includes 2 or more of the following during at least 25% of defecations with symptoms lasting over 6 weeks
1. straining
2. lumpy or hard stools
3. sensation of incomplete evacuation
4. sensation of anorectal obstruction/blockage
manual naeuvers to facilitate defecation
under 3 defecations per week
etiology of chronic constipation
dietary (poor fluid intake or decrease caloric intake)
failure to heed defecation reflex
impaired physical mobility
lack of privacy
increased psychological distress
disease states that slow down GI motility (diabetes, parkinson’s, CNS injury or disease, MS)
treatment of chronic constipation
step therapy
follow up in 1-2 weeks and check stool frequency, episodes of diarrhea, dietary changes, and SE from meds
step therapy for chronic constipation
1 - relieve acute constipation through dietary modifications
2 - bulk forming laxatives and fluids
3 - PEG, Lactulose, or sorbitol
4 - short term use of stimulant then maintenance agent
5 - lubiprostone, linaclotide, prucalopride, plecanatide ($$$, usually reserved for chronic idiopathic)
referral required when the patient has
symptoms that have persistent (with appropriate intervention for greater than 2 weeks without significant relief)
black or tarry stools
marked abdominal pain or discomfort
a fever
severe NV
family history of IBD or colon cancer
drastic change in severity or nature of symptoms
prep for GI procedure
hyperosmotic or saline laxatives (PEG, OsmoPrep, Visicol, Suprep, Suclear, Prepo)
clear liquid starts day prior to procedure in the afternoon/evening
drinking large quantities of fluid is key
use great caution in patients with heart failure, renal disease, electrolyte abnormalities
promote regular bowel habits
include ample fluids and fiber in diet
do not ignore the urger to defecate
establish a regular, unhurried time for BM
encourage patients to defecate when colonic activity is greatest (first thing in the morning, within 30 minutes after meal)
ample fluid and fiber diet
6-8 glasses of water per day
add in high fiber foods to diet slowly (20-30g per day; increase over 7-10 days to minimize gas and to promot natural fiber degradation)
eat prunes (high concentration of simple sugars)
alternative to prunes include fresh green kiwifruit, dried pitted prunes, power psyllium
constipation in spinal cord injury pt
routine use of bowel stimulants
usually suppositories
constipation in pregnancy
diet, fiber, docusate
senna in more severe cases
constipation in diabetes
use prokinetic agents (metoclopramide, prucalopride)
stimulants
constipation in patients on O
stimulants
then add docusate, lactulose, or PEG PRN
avoid bulk laxatives
Opiod receptor antagonist when other treatment doesn’t work (Methylnaltrexone, Naloxegol)
Methylnaltrexone (Relistor)
treats OIC
8-12 mg SQ every other day
expect BM within 30 minutes
very expensive
