28. Constipation Flashcards
Chronic constipation timeline
sx at least 3mo
Constipation severe with constant pain, termed?
obstipation
GI tract - amount received vs small intestine all but absorbs ? amount
9-10L/day
500cc
Primary constipation 3 main types
normal transit
slow transit - neurologic changes to cells of Cajal
disorders of defecation - impaired smooth m contraction in rectum or difficulty relaxing m of defecation
Causes of secondary constipation
diet
meds
med/psych conditions
why is fibre helpful for constipation?
increases stool weight
page 317
List 4 congenital causes of secondary constipation
hirschsprung
imperforate anus
anorectal atresia
aganglionosis
List 4 neurologic causes of secondary constipation
Chronic diseases (multiple sclerosis, Parkinson dis- ease, diabetic neuropathy)
Spinal cord injury Cerebrovascular accident
List 4 metabolic causes of secondary constipation
diabetes
hypercalcemia
hypokalemia
hypothyroid
hypomagnesemia
List 3 myopathic causes of secondary constipation
systemic sclerosis
amyloidosis
List 4 structural causes of secondary constipation
obstructing tumor or stricture
intuss
rectocele
rectal prolalpse
rectal abscess
List 5 medication that have SE causing secondary constipation
Opiates
Iron or calcium supplements Calcium channel blockers Antidepressants
Diuretics
Antipsychotics Anticholinergics Antiepileptics Antiparkinson drugs
List 3 psych causes of secondary constipation
abuse
ED
affective disorders
List 3 “other” causes of secondary constipation per Rosen’s box 28.1
dehydr
immob
pregnancy
postop pain
dietary factors
Red flag hx questions for constipation
fever
anorexia
nausea/emesis
blood stool
anemia
sign w loss
fhx colon ca
onset constip >50
acute onset in elderly
If no metabolic, deitary or med/medical/psych causes of constipation in a normal abdo and rectal exam, how to tx if acute?
osmotic stim laxative
- peg, senna, bisacodyl, milk of magnesia
No relief try an intestinal secretogogue, prokinetic agent, opioid induced can tyr meythlnaltrexone or naloxegol
If chronic constipation in a normal abdo/rectal exam with no cause of metabolic, dietary, med/med/psych causes, 4 steps:
tep 1 – Lifestyle, dietary
modifications (increase activity, increase fiber and daily water intake)
Step 2 – Bulk laxatives (psyllium seed, methylcellulose, etc.)
Step 3 – Osmotic laxatives (low dose PEG, lactulose, sorbitol), or stimulants (senna, bisacodyl) Step 4 – Intestinal secretagogues (lubiprostone, linaclotide, plecanatide); prokinetic agents (prucalopride); If opioid induced -naloxegol, methylnaltrexone
If constipation with fissure and or pain on defection: how to tx
- Docusate (stool softener)
- Mineral oil/glycerin * Manual disimpaction-may require systemic analgesia if large volume of impacted stool is present
If find perirectal abscess on exam, tx?
drainage
How do intestinal secretogogues work?
tx both chr constipation and constip predom IBS by stimulating intestinal fluid secretion (incr amount of fluid stool and decr transit time)
Name 3 kinds of bulk laxatives
psyllium/metamucil
methylcellulose/citrucel
polycabophil/fibercon
Name 5 different osmotic laxatives
mag or na salts
mag hydroxide/milk of magnesia
mag citrate
na phopshate/fleet
poorly absorbed surgars
lactulose
sorbitol
PEG
Onset action of peg
24-96h
onset of action lactulose
24-48h
mag citrate onset to action
0.5-6h
Name 2 stimulant laxatives
senna
bisacodyl
name 4 stool softners
docusate na
mineral oil/fleet enema
intestinal secretagogues
Peripherally acting mu opioid receptor antagonists
methylnaltrexone
naldemdine
naloxegol
