What is the best course of treatment for a 72-year-old female patient with gastrointestinal symptoms, including nausea, vomiting, diarrhea, and weight loss, who has a history of diverticulosis, possible diverticulitis, and suspected leaky bowel syndrome?

Immediate Management for 72-Year-Old with Acute GI Illness and Chronic Diverticulosis

This patient requires urgent CT scan with IV contrast to rule out acute diverticulitis or other serious pathology, given her acute vomiting/diarrhea episode, persistent nausea, abdominal tenderness, 5-pound weight loss, and known diverticulosis. 1

Urgent Diagnostic Workup (Within 24-48 Hours)

Imaging is mandatory given her clinical presentation:

• CT abdomen/pelvis with IV and oral contrast to evaluate for diverticulitis, abscess, perforation, bowel obstruction, or alternative diagnoses (ischemic colitis, malignancy) 1
• Her diffuse tenderness, particularly in the left lower quadrant where she reports maximal pain, combined with recent acute illness and known diverticulosis raises significant concern for complicated diverticular disease 1

Laboratory studies needed now:

• Complete blood count (looking for leukocytosis >15 × 10^9 cells/L which indicates higher risk) 1, 2
• C-reactive protein (CRP >140 mg/L indicates higher risk for progression) 1, 2
• Comprehensive metabolic panel (assess electrolytes given recent vomiting/diarrhea and possible dehydration) 2
• Stool studies including C. difficile toxin (mandatory given diarrhea) 1, 2

Immediate Symptomatic Management

For nausea/vomiting:

• Prescribe ondansetron 4-8 mg every 8 hours as needed (preferred over metoclopramide given her constipation issues) 3
• Warn her that antiemetics can worsen constipation 1

For bowel management during acute phase:

• Clear liquid diet until symptoms improve, then advance as tolerated 1
• MiraLAX 17 grams daily (not just as needed) to prevent constipation while on antiemetics 1
• Continue psyllium but increase to daily dosing (not every other day) once she can tolerate solids 1

Hydration:

• If she cannot maintain oral hydration, she needs IV fluids 2
• Her "wet" sensation and possible fluid wave on exam warrant investigation but could represent ascites, which would be visible on CT 1

Antibiotic Decision

Hold antibiotics until CT results unless she develops fever, worsening pain, or signs of sepsis 1. The 2021 AGA guidelines state that antibiotics can be used selectively in uncomplicated diverticulitis, but they ARE indicated if: 1

• Patient has comorbidities or frailty (she has multiple chronic conditions)
• Refractory symptoms or vomiting (she has persistent nausea 3 days post-acute episode)
• CRP >140 mg/L or WBC >15 × 10^9 cells/L
• CT shows fluid collection or longer segment of inflammation

If antibiotics are needed: Ciprofloxacin 500 mg twice daily plus metronidazole 500 mg three times daily for 7-10 days 1, 2

Follow-Up Colonoscopy Timing

She needs colonoscopy 6-8 weeks after complete symptom resolution to rule out malignancy, given: 1

• Her age (72 years old)
• Known diverticulosis with new acute symptoms
• Abdominal tenderness and weight loss
• The prevalence of colon cancer is 1.9% after diverticulitis episodes, higher (7.9%) if complicated 1

Do NOT perform colonoscopy during the acute/recovery phase as it increases perforation risk and patient discomfort 1

Address Her Chronic Bowel Issues After Acute Phase Resolves

Her chronic constipation with manual water enema use indicates significant colonic dysmotility 4, 5. Once acute illness resolves (1-2 weeks):

Structured bowel regimen:

• Psyllium fiber 1 tablespoon (not 1 teaspoon) daily with adequate water 1, 5
• MiraLAX 17 grams daily (she can use this long-term safely; dependency concerns are overstated) 1
• Discontinue her manual water enema technique—this is not addressing the underlying problem 5

Dietary modifications:

• High-fiber diet: whole grains, fruits, vegetables, legumes (target 25-30 grams daily) 5, 6
• Avoid red meat and sweets 2
• Regular meal timing to promote colonic motility 5

Gastroenterology Referral

She needs GI consultation for: 1

• Evaluation of chronic abdominal pain and bowel dysfunction (possible symptomatic uncomplicated diverticular disease or SCAD—segmental colitis associated with diverticulosis) 1, 7, 5
• Consideration of EGD if upper GI symptoms persist (she reported undigested food after many hours) 1, 4
• Possible anorectal manometry if constipation persists despite medical management 1

Critical Pitfalls to Avoid

Do not dismiss her "leaky bowel" concerns without proper evaluation 1. True intestinal permeability causing peritonitis would make her critically ill, but she may have: 1

• Segmental colitis associated with diverticulosis (SCAD), which can mimic IBD 1, 7
• Microscopic colitis (can cause chronic diarrhea/wetness sensation) 1
• These require colonoscopy with biopsies for diagnosis 1, 7

Do not continue her current sporadic fiber/laxative regimen—it perpetuates the cycle of constipation and manual disimpaction 1, 5

Do not attribute all symptoms to IBS or functional disorders until structural pathology is excluded with imaging and endoscopy, especially given her age and alarm features (weight loss, new symptoms) 1

One-Week Follow-Up Visit

Schedule return visit in 7 days to: 1

• Review CT and laboratory results
• Assess response to antiemetics and dietary modifications
• Determine if antibiotics were needed and evaluate response
• Ensure she can maintain oral intake and has normal bowel movements
• Arrange GI referral and colonoscopy scheduling

If she develops fever, worsening abdominal pain, inability to tolerate oral intake, or signs of peritonitis before the follow-up visit, she needs emergency department evaluation 1, 2