Constipation – Jacob Parnell
Background
- Always consider if pt is at risk for obstruction (see SBO section)
- Lactulose can cause severe cramping and bloating frequently
- Can exchange PEG for lactulose in cirrhosis (but usually more bloating)
- Titrate lactulose BID to QID until 3-4 BMs achieved in cirrhosis
- Combination therapy usually most effective
- In pts with renal dysfunction/CKD, avoid Fleet enemas (sodium phosphate load)
Evaluation
- Typical causes: medications (opioids, antidepressants, iron, anticholinergics)
- Poor diet (low-fiber), low fluid intake, reduced mobility, acute illness, electrolyte disturbances, IBS, GI disease (IBD, colon cancer)
- Clinically diagnosis, no need for KUB/CT scans unless obstruction suspected
- Consider BMP to evaluate electrolytes
- Rectal exam can be used to exclude obstructing rectal mass or fecal impaction
Management
- Stop any above offending meds as possible
- Increase water intake
- Escalating pathway for constipation:
- Senna BID + PEG (can give several times a day) try bisacodyl suppository then finally can try enema—tap water enema or SMOG enema (saline, mineral oil, glycerine)
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Laxatives |
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Mechanism |
Examples |
Effects |
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Bulking-agent |
Psyllium seed (Metamucil) |
Absorb water and ↑ fecal bulk |
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Osmotic Laxatives |
Polyethylene glycol (PEG) (Miralax, Golytely), Lactulose Mag citrate |
Poorly absorbed sugars or saline are hyperosmotic—pull fluid into GI tract |
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Stimulant Laxative |
Senna, Bisacodyl (Dulcolax) |
Stimulates release of electrolytes by the mucosa |
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Stool Softener |
Docusate (Colace, Phillips) |
Minimal efficacy if any |
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Emollient |
Mineral oil |
Lubricates stool |
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Enema |
Tap water, soap sud, lactulose (never use Fleet enema) |
Helps stimulate stool release |
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Opioid antagonist |
methylnaltrexone |
Important role in narcotic-induced constipation and paralytic ileus |
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Acetylcholinesterase inhibitor |
Neostigmine: indicated in Ogilvie’s syndrome if cecal diameter >12 cm. Relative contraindications include recent MI, acidosis, asthma, bradycardia, PUD, and beta-blockers. Decompression with colonoscopy used for select cases of Ogilvie’s refractory to medical management.
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Administer 2 mg via slow IV over 5 min (monitor for bradycardia hypotension, asystole, seizures) |
Additional Information
- “The hand that writes for opioids is also the hand that writes for a bowel regimen”
- Senna BID + PEG daily (up to TID)
- If severe constipation already developed, do above plus try methylnaltrexone
- CF pts (at risk for distal intestinal obstructive syndrome or DIOS)
- Not treated as true obstruction but rather like constipation
- PEG (QID) or just order “golytely” prep as if for colonoscopy preparation