Constipation: < ~3 BM/wk ➔ sensation of incomplete bowel emptying, straining

Obstipation: complete inability to pass stool or gas

Primary Constipation (no identifiable cause)

• Normal transit (diet, ↓ fiber/water)

• Slow transit 

• Pelvic floor dyssynergia

• In kids attending school ➔ avoidance of going to school bathroom (constipation ➔ urinary incontinence)

Secondary constipation 

• Drug-induced (opioids, β-blockers,  CCB, Fe, antidepressants)

• Metabolic (hypothyroid)

• Neurologic (spinal cord lesion) ➔ absent anal wink reflex

• Mechanical (colon cancer)

SSX/DX:

• Rome criteria:

  • Any two of following with 25% of BMs in last 3mos, with ssx presenting in last 6mos

    • < 3 BM per week

    • Straining

    • Lumpy hard stool

    • Sensation of incomplete evacuation

    • Sensation of anorectal obstruction or blockage

    • Digital maneuvers

• RED FLAG FEATURES (requiring investigation)

  • Kids: Delayed meconium passage (48hrs) in newborn, constipation <1mo old, bilious vomiting (yellow/green)

  • Adults: Hx of IBD or colorectal cancers, blood, ABD mass, weight loss, >50yo

    • Check for hypoK, hypothyroid, DM and do DRE to r/o rectal carcinoma 

TX:

• First line: exercise, hydration, fiber

  • ADD bulk forming (psyllium or methylcellulose)

    • Pt must have adequate water intake or ➔ worsening constipation 

    • Surfactants AKA stool softeners (docusate) have less side effects but are less effective

• Last line for unresolved constipation

  • Osmotic laxatives (polyethylene glycol, glycerin, MgOH/citrate, lactulose) 

    • Movement of water into lumen stimulates motility

    • Lactulose (BX ➔ lactic acid and quenches NH4+) for hepatic encephalopathy

      • ADR: diarrhea, dehydration; overuse/abuse ➔ alkalosis, rebound constipation

  • Secretory/stimulant laxatives (senna, bisacodyl) 

    • Electrolyte shift into lumen ➔ depolarization ➔ ↑ contractions

      • ADR: diarrhea (↑↑ K loss) , dehydration; overuse/abuse ➔ alkalosis, rebound constipation

• TX fecal impaction

  • R/o perforation and perform manual disimpaction (digital or endoscopic)

Diarrhea

• Acute diarrhea : <14d

• Persistent Diarrhea: >14d <30d

• Chronic: >30d

TX:

• PO > IV hydration

• Loperamide or bismuth for sx relief

• Severe diarrhea: azithro OR cipro - shiga toxin-producing E. coli (STEC) should NOT get ABX

• Giardiasis: metronidazole

• C. diff: PO vanco

Irritable Bowel Syndrome

• Functional disorder WITHOUT specified cause

• Patho complicated and not fully understood

  • Abnormal motility, secretion, permeability with psychosocial factors

SSX:

• ABD pain with diarrhea and/or constipation

• Pain (usually relief of) is related to defecation

• Other sx can include fatigue, pain, dysmenorrhea, ↓ appetite

• PE typically normal

DX: Rome IV criteria

• Recurrent abdominal pain averaging  1d/wk over last 3mo AND at least two:

  • Pain related to defecation

  • ∆ in stool frequency

  • ∆  stool appearance

TX:

• Diet ➔ improved sx

  • Avoid gas producing foods: beans, onions, raisins, Brussels sprouts, bagels, etOH, caffeine 

  • Low FODMAPs (fermentable oligo-, di-, and monosaccharides and polyols): fructose containing foods

• Exercise ➔ improved sx