In this episode of Hospital Medicine Unplugged, we blitz acute diverticulitis—spot it early, stage it right, treat what matters, and prevent the encore. We open with the why: ~200,000 US admissions/year and >$6.3B in costs. Risk stacks with age >65, obesity, NSAIDs/steroids/opioids, HTN/DM2, connective-tissue disease, and genetics. Patients roll in with LLQ pain, fever, leukocytosis, N/V. Do-firsts in the ED/ward: IV access, analgesia (acetaminophen first; minimize opioids; avoid routine NSAIDs), antiemetics, IV fluids, and labs (CBC, BMP, UA, CRP). CT A/P with IV contrast is the diagnostic gold standard—~99–100% sensitivity/specificity—to confirm diverticulitis and flag complications. Call the type:• Uncomplicated = localized inflammation, no abscess/perf/fistula/obstruction.• Complicated = any abscess, perforation, fistula, obstruction/stricture, peritonitis. Who needs a bed? Admit for complicated disease, high fever (>38.5°C), marked leukocytosis, can’t tolerate PO, immunosuppression, serious comorbidity, or no home support. Outpatient is reasonable for low-risk, imaging-confirmed uncomplicated cases with reliable follow-up. Treatment—build the supportive core:• Bowel rest → advance diet as tolerated in 2–3 days.• Antibiotics are not routine for all uncomplicated cases; reserve for high-risk (elderly, immunocompromised, persistent fever/WBC, severe comorbidity, pregnancy).• If antibiotics needed: IV ceftriaxone + metronidazole or ampicillin/sulbactam; step down to orals when improving. Typical 4–7 days (uncomplicated needing abx); 7–14 days (complicated)—tailor to response and source control. If the core buckles—manage complicated disease:• Abscess <3 cm: IV antibiotics alone.• Abscess ≥3 cm: Percutaneous drainage + IV antibiotics (success up to ~80%).• Generalized peritonitis, failed drainage, obstruction, or clinical deterioration: Urgent surgical consult; consider resection ± primary anastomosis vs Hartmann based on stability.• Re-image at 48–72 h if no improvement. Special populations you won’t want to miss:• Elderly: lower threshold for CT; antibiotics more often indicated; individualize operative decisions.• Immunocompromised: always treat with antibiotics, admit liberally, and involve surgery early; higher risk of rapid progression despite mild exam. Complication radar: abscess/phlegmon, perforation/peritonitis, fistula (look for pneumaturia/fecaluria), obstruction/stricture, bleeding, sepsis/AKI. Risk rises with CRP >140 mg/L, WBC >15 ×10⁹/L, extraluminal air/fluid on CT, long inflamed segment, and major comorbidity. Colonoscopy after the dust settles:• Complicated diverticulitis: schedule 6–8 weeks post-resolution (unless a high-quality colonoscopy was done within a year and no alarm features).• Uncomplicated: individualized—consider prior screening and symptoms; investigate early for alarm signs (weight loss, anemia, bleeding, change in caliber, persistent pain). Secondary prevention that sticks:• High-fiber, plant-forward diet, physical activity, weight optimization, avoid tobacco, and limit chronic NSAIDs (keep aspirin for CAD when needed).• No routine mesalamine, probiotics, or rifaximin—evidence doesn’t support them.• Elective surgery isn’t about episode counting; decide based on severity, smoldering symptoms, fistula/stricture, and patient goals. We close with the diverticulitis bundle: (1) confirm with contrast CT; (2) supportive care first (fluids, pain control, diet advance); (3) selective antibiotics—don’t overuse; (4) drain abscess ≥3 cm; (5) call surgery for peritonitis/obstruction/failed nonop care; (6) reassess at 48–72 h, re-image if stalled; (7) plan post-acute colonoscopy (complicated: 6–8 weeks); (8) lock in lifestyle prevention. Imaging-led, selective with antibiotics, decisive with source control—treat what’s complicated, spare what isn’t, and keep patients out of the readmit loop.