Overview
Definition:
Acute diverticulitis is an inflammation or infection of diverticula, which are small, bulging pouches that can form in the lining of the digestive system
It most commonly affects the sigmoid colon
Complications include perforation, abscess formation, fistula, and obstruction.
Epidemiology:
Diverticular disease is highly prevalent in Westernized countries, with incidence increasing with age
Over 50% of individuals over 60 have diverticula, and about 10-20% of those with diverticula develop symptomatic diverticulitis
Risk factors include low-fiber diet, obesity, sedentary lifestyle, smoking, and NSAID use.
Clinical Significance:
Acute diverticulitis is a common cause of acute abdominal pain requiring medical attention and a frequent indication for elective or emergency surgery
Understanding its pathophysiology, accurate staging (especially Hinchey), and appropriate management, including surgical intervention, is crucial for optimal patient outcomes and preventing severe complications.
Clinical Presentation
Symptoms:
Left lower quadrant (LLQ) abdominal pain, typically acute in onset and constant
Fever, often low-grade
Nausea and vomiting
Changes in bowel habits, such as constipation or diarrhea
Urinary symptoms may be present if the bladder is involved by inflammation or a fistula.
Signs:
Tenderness in the LLQ on abdominal examination, often with localized peritoneal signs (rebound tenderness, guarding)
Palpable mass may be present in cases of phlegmon or abscess
Vital signs may show fever and tachycardia
Rectal examination may reveal tenderness.
Diagnostic Criteria:
Diagnosis is primarily clinical, supported by imaging
Clinical criteria typically include LLQ pain, fever, and leukocytosis
Imaging confirms the diagnosis and assesses for complications
Specific diagnostic criteria for severe disease or peritonitis are often based on CT findings and surgical assessment.
Diagnostic Approach
History Taking:
Detailed history of abdominal pain characteristics (onset, location, severity, character)
Associated symptoms (fever, nausea, vomiting, bowel changes, urinary symptoms)
Past medical history of diverticulosis or previous diverticulitis episodes
Dietary habits, lifestyle, medications (NSAIDs, steroids).
Physical Examination:
Systematic abdominal examination, paying close attention to tenderness, guarding, rebound tenderness, and the presence of any palpable masses
Assess for signs of peritonitis
Evaluate vital signs
Perform a digital rectal examination.
Investigations:
Laboratory tests: Complete blood count (CBC) to assess for leukocytosis
C-reactive protein (CRP) may be elevated
Electrolytes and renal function tests
Imaging: CT scan of the abdomen and pelvis with intravenous and oral contrast is the gold standard for diagnosing acute diverticulitis, identifying its severity, and detecting complications like abscesses or perforation
Ultrasound may be used in pregnant patients or as an initial bedside tool but is less sensitive than CT
Colonoscopy is contraindicated in the acute phase due to the risk of perforation but should be considered after resolution of inflammation to evaluate the extent of diverticular disease and rule out malignancy.
Differential Diagnosis:
Appendicitis (especially if the sigmoid colon is redundant or in cases of atypical presentation)
Inflammatory bowel disease (Crohn's disease)
Colorectal cancer
Ovarian pathology (cyst, torsion)
Ureteral colic
Infectious colitis
Mesenteric ischemia.
Hinchey Staging
Stage I:
Pericolic or rectal muscularis propria inflammation/phlegmon.
Stage Ii:
Pericolic or pelvic abscess.
Stage Iii:
Generalized peritonitis with purulent effusion.
Stage Iv:
Generalized peritonitis with fecal effusion (generalized fecal contamination of the peritoneal cavity).
Management
Initial Management:
For uncomplicated diverticulitis (Hinchey I): Bowel rest (clear liquids or NPO), intravenous fluids, and intravenous antibiotics
Pain management with analgesics
Monitoring for signs of worsening or complications
For complicated diverticulitis (Hinchey II-IV): Immediate surgical consultation, broad-spectrum intravenous antibiotics, and often percutaneous drainage for abscesses or immediate surgical intervention.
Medical Management:
Antibiotics: Typically a broad-spectrum regimen covering gram-negative rods and anaerobes
Common regimens include ciprofloxacin plus metronidazole, or amoxicillin-clavulanate
Duration is usually 7-10 days, adjusted based on clinical response
IV antibiotics are used for more severe cases or those requiring hospitalization
Oral antibiotics may be used for mild, uncomplicated cases managed as outpatients.
Surgical Management:
Indications for surgery include: Failure of medical management, recurrent diverticulitis, complications such as perforation with generalized peritonitis (Hinchey III/IV), abscess unresponsive to percutaneous drainage, fistula formation, or obstruction
Elective sigmoid colectomy with primary anastomosis is the procedure of choice for patients with recurrent or complicated diverticulitis
In acute settings with peritonitis or significant contamination, a Hartmann's procedure (resection with end colostomy and rectal stump closure) may be necessary, with plans for subsequent reversal.
Supportive Care:
Nutritional support: Initially NPO or clear liquids
advance diet as tolerated
Pain control
Close monitoring of vital signs, abdominal examination, and laboratory parameters
Nursing care for IV access, fluid management, and wound care if applicable.
Complications
Early Complications:
Perforation (free perforation into the peritoneum leading to peritonitis)
Abscess formation (localized collection of pus)
Fistula formation (colo-vesical, colo-colic, colo-cutaneous)
Bowel obstruction due to phlegmon or stricture
Sepsis.
Late Complications:
Stricture formation leading to chronic obstruction
Recurrent diverticulitis
Incisional hernia
Adhesions
Chronic fistulas
Increased risk of colorectal cancer in patients with a history of diverticulitis (though this association is debated).
Prevention Strategies:
High-fiber diet is recommended to prevent the development of diverticular disease
Regular exercise, weight management, and smoking cessation may reduce risk
For patients with a history of diverticulitis, some recommend avoiding nuts and seeds, though evidence for this is weak
Prophylactic antibiotics are generally not recommended for asymptomatic diverticular disease.
Prognosis
Factors Affecting Prognosis:
Severity of diverticulitis (Hinchey stage)
Presence of complications (abscess, perforation)
Patient's overall health status and comorbidities
Timeliness and appropriateness of treatment
Response to medical and/or surgical management.
Outcomes:
Most uncomplicated cases resolve with medical management
Complicated cases requiring surgery have higher morbidity and mortality
Recurrence rates vary, but elective surgery after an episode of complicated diverticulitis or multiple episodes of uncomplicated diverticulitis can significantly reduce recurrence risk.
Follow Up:
Patients treated non-operatively should have follow-up to ensure resolution of symptoms
Colonoscopy after recovery is recommended for all patients with acute diverticulitis to exclude underlying malignancy and assess the extent of diverticular disease
Patients who undergo surgery require routine postoperative follow-up according to surgical protocol.
Key Points
Exam Focus:
Hinchey staging is critical for guiding management
CT scan is the primary imaging modality
Indications for surgery in acute diverticulitis: peritonitis, unresolving abscess, fistula, obstruction, recurrent disease
Hartmann's procedure is for severe acute peritonitis
elective sigmoid colectomy is for elective/recurrent cases.
Clinical Pearls:
Always consider diverticulitis in patients with left lower quadrant pain, especially older adults
Remember that right-sided diverticulitis can mimic appendicitis
Do not perform colonoscopy during an acute episode of diverticulitis
Percutaneous drainage of abscesses is often preferred over immediate surgery for contained collections.
Common Mistakes:
Delaying surgical consultation in patients with signs of peritonitis or sepsis
Misinterpreting CT findings, leading to inadequate treatment
Performing colonoscopy during the acute phase
Underestimating the risk of recurrence and not recommending elective surgery when indicated.