Cause:Drugs, diet, colon lesions, hypothyroid, autonomic neuropathies, hypocalcemia
Sx:Abdominal cramps; <3 stools/wk
Si:Abdominal mass from stool
Fecal impaction (Nejm 1989;321:658) with fever, dyspnea, encopresis (diarrhea around a fecal impaction) (Peds Rv 1998;19:22; Ped Clin N Am 1996;43:279; Clin Ped 1991;30:669) esp in children age 3-5 yr
r/o hypothyroidism, Hirschsprung's in children (rarely have fecal incontinence)
Lab:TSH r/o hypothyroidism, electrolytes in recent onset, FOBT in elderly to assess for obstructing mass lesion
Xray:Can use Sitzmark radioopaque markers to assess GI transit; colonoscopy if obstruction is suspected, caution regarding risk of bowel perforation, rarely manometry
Rx:
1st: Increased fiber (25 gm/d) and water in diet.
Laxatives:
- 2nd: Psyllium (Metamucil, etc)
- 3rd:
- Polyethylene glycol (PEG) (Miralax, Colyte, GoLYTELY) tbsp/8 oz water qd
- Sorbitol (Cystosol) 70% soln, 30-60 cc po hs
- Lactulose (Hepatic Failure: Hepatic Coma/Encephalopathy) with fewer side effects and cheaper (Am J Med 1990;89:597)
- Emollients like dioctyl Na succinate (Colace, Surfak)
- Lubricants like mineral oil
- Mg compounds like Milk of Magnesia
- Stimulant/irritants like cascara, senna, and castor oil
- 4th: Prucalopride (Resolor) 2-4 mg po qd, a 5-HT agonist, 50% effective in severe constipation (Nejm 2008;358:2402), not yet available in US
of ENCOPRESIS: bisacodyl (Dulcolax) 5 mg ii tabs po qd with mineral oil; enemas if football-sized stool