Diverticular disease

• Diverticula are small sac-like outpouchings of mucosa through weak points in the colon wall where blood vessels enter
• Diverticulosis = diverticula present, usually without symptoms; prevalence rises with age
• Diverticulitis = inflammation or infection of a diverticulum, often from micro-perforation
  • Uncomplicated: localized inflammation
  • Complicated: abscess, perforation, fistula (e.g., colovesical — to the bladder), obstruction, or peritonitis
• Diverticular bleeding = a vessel at the neck of a diverticulum ruptures: sudden, painless, large-volume bright red or maroon rectal bleeding
• Risk factors: older age, low-fiber diet, obesity, physical inactivity, smoking, NSAIDs and opioids, high red-meat intake
• In Western populations, most diverticula are in the sigmoid colon (left side); right-sided disease is relatively more common in Asian populations

Irritable bowel syndrome (IBS)

• A disorder of gut–brain interaction: recurrent abdominal pain related to defecation with altered bowel habits, without structural or biochemical disease
• Mechanisms: visceral hypersensitivity, altered motility, gut microbiome changes, post-infectious changes, and psychological stress
• IBS does not cause cancer, inflammatory bowel disease, or intestinal damage
• Subtypes by predominant stool form: IBS-C (constipation), IBS-D (diarrhea), IBS-M (mixed), IBS-U (unclassified)

Diverticulitis

• LLQ pain (sigmoid), steady, may be tender to palpation; RLQ pain if right-sided disease
• Fever, nausea, change in bowel habits (constipation or diarrhea), leukocytosis
• Complicated disease: palpable mass (abscess), peritoneal signs (perforation), pneumaturia or fecaluria (colovesical fistula), distension (obstruction)
• Older adults and immunosuppressed clients may have few signs even with perforation

Diverticular bleeding — assess stool color, amount, and frequency, vital signs, orthostatic changes, hemoglobin.

IBS

• Crampy pain relieved or changed by defecation, bloating, urgency, sense of incomplete evacuation, mucus in stool
• Symptoms often worsen with stress and certain foods

Alarm features that suggest organic disease (not IBS) — investigate

• Onset at age 45–50 or older, rectal bleeding or melena, unintentional weight loss, iron-deficiency anemia, nocturnal symptoms, fever
• Family history of colorectal cancer, IBD, or celiac disease

Diverticular disease

IBS — Rome IV criteria

• Recurrent abdominal pain on average at least 1 day per week in the last 3 months, associated with 2 or more of:
  1. Related to defecation
  2. Change in stool frequency
  3. Change in stool form (appearance)
• Symptoms began at least 6 months before diagnosis
• Current guidance favors a positive diagnosis from symptoms plus limited testing, rather than exhaustive exclusion
• Limited tests: CBC; celiac serology in IBS with diarrhea; CRP or fecal calprotectin to screen for IBD; colonoscopy when alarm features are present or for age-based screening

Uncomplicated diverticulitis

• Many clients can be managed as outpatients
• Antibiotics are used selectively — current guidance (ACP 2022) suggests that selected immunocompetent clients without systemic signs may recover without antibiotics. Antibiotics are given when there is systemic infection, immunosuppression, frailty, significant comorbidity, or failure to improve
• Common oral regimens: amoxicillin–clavulanate, or ciprofloxacin (or trimethoprim–sulfamethoxazole) with metronidazole
  • Fluoroquinolones: boxed warnings — tendon rupture, peripheral neuropathy, CNS effects, aggravation of myasthenia gravis; also QT prolongation, dysglycemia, aortic aneurysm risk; FDA advises reserving them for when alternatives are unsuitable
  • Trimethoprim–sulfamethoxazole: sulfa allergy, hyperkalemia, rash including Stevens–Johnson syndrome; raises INR with warfarin
  • Metronidazole: metallic taste, nausea; avoid alcohol; peripheral neuropathy with prolonged use; raises INR with warfarin
  • Amoxicillin–clavulanate: diarrhea; check penicillin allergy
• Clear liquids or low-residue diet during the acute episode, advancing as symptoms improve; analgesia with acetaminophen (avoid NSAIDs)

Complicated diverticulitis

• Hospital admission, NPO or bowel rest, IV fluids, IV antibiotics
• Abscess: small abscesses may respond to IV antibiotics alone; larger ones (commonly about 3–4 cm or more) need CT-guided percutaneous drainage plus IV antibiotics
• Generalized peritonitis / free perforation: emergency surgery — sigmoid resection with primary anastomosis (sometimes with a diverting ileostomy) or Hartmann procedure (resection with end colostomy, often reversed later)
• Elective sigmoid resection is individualized — considered after complicated disease, recurrent episodes that affect quality of life, fistula, or stricture; not simply after a set number of attacks
• Mesalamine and probiotics are not recommended to prevent recurrence

Diverticular bleeding — most stop spontaneously; resuscitation, colonoscopic or angiographic hemostasis, surgery rarely. Review NSAID, antiplatelet, and anticoagulant use.

IBS — stepwise and symptom-directed

• Education, reassurance, and a strong therapeutic relationship
• Diet: regular meals; limit caffeine, alcohol, fatty and gas-producing foods if they trigger symptoms; soluble fiber (psyllium) helps — insoluble fiber (bran) often worsens bloating; a short-term low-FODMAP diet supervised by a dietitian, followed by structured reintroduction
• Peppermint oil (enteric-coated) — low-risk option for global symptoms; may worsen heartburn
• Antispasmodics (dicyclomine, hyoscyamine): anticholinergic effects — dry mouth, urinary retention, constipation, confusion in older adults; avoid in glaucoma, obstruction, and urinary retention
• Low-dose tricyclic antidepressants (e.g., amitriptyline) for pain: sedation, constipation, anticholinergic effects, QT prolongation; dangerous in overdose; antidepressant suicidality warning in young people
• IBS-D: loperamide (do not exceed dose — cardiac toxicity); rifaximin 14-day course; eluxadoline (contraindicated without a gallbladder, with pancreatitis history, heavy alcohol use, or severe liver disease); alosetron for women with severe IBS-D (boxed warning — ischemic colitis and severe constipation; stop immediately and report rectal bleeding or worsening pain)
• IBS-C: polyethylene glycol; secretagogues linaclotide, plecanatide (diarrhea; linaclotide is contraindicated under 2 years and plecanatide under 6 years because of serious dehydration) and lubiprostone (nausea — take with food; dyspnea; use in pregnancy only if benefit outweighs risk)
• Gut-directed psychological therapies: cognitive behavioral therapy, gut-directed hypnotherapy

Listed in priority order.

1. Detect perforation, peritonitis, and sepsis — monitor vital signs, temperature, pain character, abdominal rigidity, WBC; report sudden severe or diffuse pain
2. Bleeding — monitor stool color and amount, hemoglobin, orthostatic vital signs; large-bore IV access; transfuse as ordered
3. Fluid balance — IV fluids, intake and output, electrolytes; NPO and NG care in complicated disease
4. Antibiotic administration — give on schedule; watch for C. difficile diarrhea and drug reactions
5. Pain and comfort — acetaminophen or opioids as ordered; avoid NSAIDs in diverticular bleeding and perforation risk
6. Postoperative and ostomy care after Hartmann procedure (see Colorectal Cancer)
7. IBS support — therapeutic communication: acknowledge concerns, then give accurate information (IBS is real, common, and does not turn into cancer); help identify triggers with a food and symptom diary; teach stress management

Diverticular disease

• High-fiber diet (fruits, vegetables, whole grains, legumes), gradually increased, with adequate fluids — reduces constipation and colonic pressure
• There is no need to avoid nuts, seeds, corn, or popcorn — these foods do not increase diverticulitis risk
• Regular physical activity, weight control, stop smoking; limit red meat; avoid routine NSAID use
• During an attack: clear liquids, then low-residue foods, then back to high fiber as symptoms resolve
• Take the full antibiotic course if prescribed; drink enough fluids
• Report fever, worsening pain, vomiting, rectal bleeding, or urine that is cloudy or contains air

IBS

• Symptoms can be managed; a regular routine for meals, sleep, and exercise helps
• Keep a symptom diary; try one dietary change at a time; avoid unnecessary broad restrictions (e.g., stopping all dairy without evidence of intolerance)
• Report alarm symptoms: bleeding, weight loss, fever, night-time symptoms, or a change in the usual pattern

• Diverticulitis: LLQ pain, fever, leukocytosis; confirm with CT; no colonoscopy during the acute attack
• Most serious complication: perforation with peritonitis
• Diverticular bleeding: painless, sudden, large — watch stool color and amount
• Uncomplicated diverticulitis: antibiotics selectively; complicated: IV antibiotics, drainage of larger abscesses
• Perforated diverticulitis may need Hartmann procedure (temporary colostomy)
• Prevention: high fiber + fluids; nuts, seeds, and popcorn need not be avoided
• Colonoscopy after complicated diverticulitis to exclude cancer
• IBS (Rome IV): pain ≥ 1 day/week for 3 months with 2 of: defecation-related, frequency change, form change
• IBS: soluble fiber, limited low-FODMAP trial, reduce caffeine/alcohol if triggers; lubiprostone/linaclotide for IBS-C, loperamide/rifaximin for IBS-D
• IBS does not progress to cancer — acknowledge feelings, then educate