What is Ogilvie syndrome?

What is Ogilvie Syndrome?

Ogilvie syndrome, also known as acute colonic pseudo-obstruction (ACPO), is a pathological dilation of the colon—particularly affecting the cecum and right colon—that presents with clinical and radiographic signs of large bowel obstruction despite the absence of any mechanical obstructing lesion. 1, 2, 3

Pathophysiology

• The underlying mechanism involves an imbalance in the autonomic nervous system regulation of colonic motility, specifically disruption of the parasympathetic innervation to the colon. 3, 4
• This autonomic dysregulation leads to impaired colonic motor function and progressive dilation without a physical blockage. 5

Clinical Presentation

• Patients present with abdominal distension, nausea, vomiting, and signs mimicking mechanical large bowel obstruction. 1, 2
• The condition typically occurs in debilitated or critically ill patients with serious underlying comorbidities. 2, 3
• Common associated conditions include recent major surgery (especially orthopedic procedures like hip arthroplasty), severe medical illness, metabolic derangements (particularly electrolyte abnormalities and hypercalcemia), use of anticholinergic or narcotic medications, and prolonged immobilization. 2, 4, 6

Diagnostic Criteria

• Diagnosis requires radiographic evidence of colonic dilation ≥9 cm (with cecal dilation often exceeding 12 cm) combined with clinical signs of obstruction, after excluding mechanical causes through imaging. 2, 3
• CT scan is essential to rule out mechanical obstruction and evaluate the extent of colonic dilation, looking for a characteristic sharp "cut-off" transition between dilated and non-dilated bowel segments. 1, 3
• Laboratory evaluation should include complete blood count, electrolytes (particularly potassium and calcium), BUN/creatinine, and lactate to assess for metabolic abnormalities and complications. 1

Risk of Complications

• The primary concern is colonic perforation, which carries mortality rates of 27-57% when it occurs. 7
• Cecal diameter is the critical measurement, with dimensions approaching or exceeding 12 cm considered at high risk for ischemia and perforation. 2, 3
• Other complications include aspiration pneumonia from vomiting, electrolyte disturbances, and renal dysfunction from dehydration. 1

Management Approach

Initial management should be conservative in all patients without signs of perforation or peritonitis, as this approach yields outcomes similar to or better than aggressive interventional management. 2

First-Line Conservative Treatment:

• Implement strict bowel rest (NPO status) with nasogastric tube decompression to prevent aspiration. 1, 2
• Provide aggressive intravenous fluid resuscitation to correct dehydration. 1, 3
• Correct all electrolyte abnormalities, particularly hypokalemia and hypercalcemia. 1, 6
• Discontinue all medications that impair colonic motility, including narcotics, anticholinergics, and calcium channel blockers. 1, 4
• Insert a rectal tube for decompression. 2, 3

Monitoring Requirements:

• Perform serial abdominal examinations and radiographs to monitor colonic diameter progression. 1
• Watch closely for signs of clinical deterioration including worsening abdominal pain, peritoneal signs, fever, tachycardia, or rising lactate levels. 1

Interventional Management (if conservative fails after 24-48 hours):

• Neostigmine (acetylcholinesterase inhibitor) can be administered pharmacologically to stimulate colonic motility. 2, 3
• Colonoscopic decompression is an option for refractory cases, though it carries procedural risks. 2, 3
• Recurrence prevention includes placement of a multiperforated rectal tube and oral polyethylene glycol administration. 3

Surgical Intervention:

• Surgery is mandatory only for patients with signs of peritonitis, perforation, or clinical deterioration despite 24-48 hours of medical management. 1, 3
• Surgical options include cecostomy or, in severe cases, colonic resection, but these carry high morbidity and mortality rates. 3, 4

Key Clinical Pitfalls

• A retrospective study found that 61% of patients undergoing interventional management had Ogilvie's-related complications compared to only 21% managed conservatively, suggesting overly aggressive intervention may worsen outcomes. 2
• Do not delay correction of metabolic abnormalities, as electrolyte imbalances (especially hypokalemia and hypercalcemia) are both causative and perpetuating factors. 1, 6
• Maintain high clinical suspicion in elderly postoperative patients, particularly after orthopedic procedures, as this population is at highest risk. 4, 5