What is the best next step in managing an elderly patient with abdominal distention, hypoactive bowel sounds, and a dilated cecum due to ileus?

Management of Acute Colonic Pseudo-Obstruction (Ogilvie's Syndrome)

Nasogastric drainage with serial abdominal examinations is the best next step in management for this patient with acute colonic pseudo-obstruction (cecal diameter 14 cm), followed by neostigmine administration if conservative measures fail within 24-48 hours or if the cecum reaches 12 cm or greater. 1, 2

Initial Conservative Management

The first-line approach involves supportive measures with close monitoring:

• Insert nasogastric tube for gastric decompression to relieve vomiting, reduce proximal bowel distension, and prevent aspiration pneumonia 1, 2
• Correct electrolyte abnormalities (particularly hypokalemia, hypomagnesemia, hypocalcemia) and metabolic derangements that perpetuate colonic atony 2, 3
• Discontinue all offending medications including opioids, anticholinergics, calcium channel blockers, and any drugs that inhibit intestinal motility 2, 3
• Perform serial abdominal examinations every 4-6 hours to monitor for peritoneal signs suggesting perforation or ischemia 1, 2
• Obtain daily abdominal radiographs to track cecal diameter progression 2

Critical Threshold for Escalation

If the cecal diameter exceeds 12 cm or conservative management fails after 24-48 hours, neostigmine should be administered as pharmacologic decompression 2. This patient already has a cecal diameter of 14 cm, placing him at high risk for perforation (which occurs in 3-15% of cases when cecal diameter exceeds 12 cm) 2.

Neostigmine Administration Protocol

• Dose: 2-2.5 mg IV administered slowly over 3-5 minutes with continuous cardiac monitoring 2
• Monitor for bradycardia and bronchospasm during administration; have atropine immediately available 2
• Contraindications include: mechanical obstruction (already excluded by CT), active bronchospasm, bradycardia, recent myocardial infarction, and acidosis 2
• Success rate is 60-90% with response typically occurring within 10-30 minutes 2

Why Not the Other Options?

Colonoscopic Decompression

• Reserved for neostigmine failure or contraindications to neostigmine 2
• Carries risk of perforation (1-3%) in already dilated, friable colon 2
• Should be performed by experienced endoscopist with placement of decompression tube if successful 2

Exploratory Laparotomy

• Only indicated if peritoneal signs develop (rigidity, rebound tenderness) suggesting perforation or ischemia 2, 3
• This patient lacks peritoneal signs despite grimacing with palpation 2
• Surgery should be avoided when possible as it carries high morbidity/mortality in critically ill, septic patients 3
• Decompressive laparotomy with cecostomy or right hemicolectomy is reserved for failed medical/endoscopic management or established perforation 2, 3

Common Pitfalls to Avoid

• Do not delay treatment while pursuing additional testing if clinical picture is clear 4
• Do not use prokinetic agents like metoclopramide as they are ineffective in colonic pseudo-obstruction and carry risk of tardive dyskinesia 5, 4
• Do not assume absence of peritonitis means absence of ischemia - hyperlactatemia and clinical deterioration may precede frank perforation 6, 2
• Do not place rectal tubes as there is no evidence supporting their use in colonic pseudo-obstruction management 1

Monitoring Parameters

• Vital signs every 2-4 hours looking for tachycardia, fever, or hemodynamic instability 2
• Lactate levels to assess for bowel ischemia 6, 2
• Abdominal girth measurements to track distension objectively 2
• Urine output via Foley catheter during fluid resuscitation 1

Nutritional Considerations

• Keep patient NPO initially until decompression achieved 1
• Once resolved, advance diet cautiously with low-fat, low-fiber, frequent small meals 6, 4
• Consider enteral nutrition via nasojejunal tube if prolonged ileus develops, before resorting to parenteral nutrition 4