What is the assessment and management plan for a patient diagnosed with bowel obstruction?

Assessment and Management of Bowel Obstruction

Initial Clinical Assessment

Begin immediate resuscitation with IV crystalloid fluids while simultaneously obtaining a focused history and performing targeted physical examination to identify high-risk features requiring urgent surgical intervention. 1, 2

Critical History Elements

• Prior abdominal surgery has 85% sensitivity and 78% specificity for adhesive small bowel obstruction 1
• Last passage of flatus/feces (absent in 90% and 80% of cases respectively) 1, 3
• Previous diverticulitis or chronic constipation suggests volvulus or diverticular stenosis 1
• Rectal bleeding and weight loss indicate possible malignancy 1
• Medications affecting peristalsis to differentiate from pseudo-obstruction 1

Physical Examination Red Flags

• Abdominal distension (present in 65% of cases) 3
• Peritonitis, fever, hypotension, or diffuse abdominal pain suggest strangulation/ischemia requiring immediate surgery 1, 4
• Abnormal bowel sounds are a reliable finding 4

Laboratory Assessment

• Complete metabolic panel, renal function, lactate, and coagulation profile 2
• Marked leukocytosis with elevated absolute neutrophil count strongly suggests ischemia or perforation requiring urgent surgical consultation 2

Diagnostic Imaging Strategy

CT scan with IV contrast is the preferred diagnostic test with >90% accuracy for bowel obstruction and should be obtained immediately in all patients. 2, 5

CT Advantages Over Plain Films

• Plain radiographs have only 50-60% sensitivity and are inconclusive in 20-30% of cases 5
• CT has ~90% accuracy for predicting strangulation and need for surgery 5
• CT identifies the level, cause, presence of ischemia, and multiple obstruction sites 2, 5

Alternative Imaging

• Ultrasound has 90% sensitivity and 96% specificity when dilated loops >2.5 cm are visualized 5
• MRI is preferred for pregnant women and children (95% sensitivity, 100% specificity) 5

Initial Supportive Management

All patients require immediate nasogastric tube decompression, Foley catheter placement, and aggressive fluid resuscitation while determining operative versus non-operative candidacy. 2, 4, 6

Standard Supportive Measures

• Nasogastric tube decompression prevents aspiration pneumonia and relieves symptoms 2, 4
• Foley catheter to monitor urine output and hydration status 2
• IV fluid resuscitation to correct dehydration and electrolyte abnormalities 2, 4
• Analgesia for pain control 4

Determining Operative vs. Non-Operative Management

Immediate surgical intervention is mandatory for any patient with signs of ischemia, strangulation, or perforation (peritonitis, fever, hypotension, marked leukocytosis with elevated ANC), as mortality reaches 25% if delayed. 2, 4, 3

Indications for Immediate Surgery

• Clinical peritonitis or signs of strangulation 2, 4, 3
• CT findings suggesting bowel compromise 2, 6
• Marked leukocytosis with elevated ANC 2
• Incarcerated hernias (significantly higher strangulation risk than other causes) 3

Water-Soluble Contrast Protocol for Non-Operative Candidates

For patients without signs of ischemia, administer 80 mL Gastrografin via nasogastric tube after adequate gastric decompression, with abdominal X-rays at 4,8,12, and 24 hours. 5, 6

Contrast Protocol Interpretation

• Contrast reaching colon within 5 hours predicts 90% resolution without surgery 6
• No contrast in colon at 24 hours indicates failed non-operative management and need for surgery 5, 6
• Direct correlation exists between time to contrast passage and hospital length of stay 6

Contrast Protocol Precautions

• Administer only after adequate gastric decompression to prevent aspiration pneumonia and pulmonary edema 5
• Use caution in elderly patients and those at high risk of gastropathy due to high osmolarity causing fluid shifts 5
• Consider delaying administration to 48 hours post-admission to reduce aspiration and dehydration risk 5

Non-Operative Management Success Rates

• Approximately 59% of patients can be managed conservatively 3
• 41% ultimately require surgery, with 47% needing operation on the first day 3

Etiology-Based Risk Stratification

Small Bowel Obstruction (76% of cases)

• Adhesions: 55-75% of small bowel obstructions 1
• Hernias: 15-25% 1
• Malignancies: 5-10% 1

Large Bowel Obstruction (24% of cases)

• Cancer: 60% of large bowel obstructions 1
• Volvulus: 15-20% 1
• Diverticular disease: 10% 1

Strangulation Risk by Etiology

• Hernias, large bowel cancer, and adhesions are the most frequent causes of bowel ischemia (57.2%, 19.1%, 14.3%), necrosis (42.8%, 21.4%, 21.4%), and perforation (50%, 25%, 25%) 3
• Overall incidence: ischemia 14%, necrosis 9.3%, perforation 5.3% 3

Management of Malignant Bowel Obstruction

For malignant obstruction with signs of ischemia, perform immediate surgical consultation and intervention; for those without ischemia, consider pharmacologic management and palliative procedures. 2, 7

Surgical Options for Malignant Obstruction

• Resection with primary anastomosis, intestinal bypass, or stoma creation depending on disease extent and patient status 2

Medical Management for Malignant Obstruction

• Opioids for pain control 2, 7
• Antiemetics (avoid prokinetic agents like metoclopramide in complete obstruction) 2, 7
• Corticosteroids to reduce inflammation 2, 7
• Somatostatin analogs to reduce GI secretions 2, 7
• Anticholinergics to reduce secretions and motility 2, 7

Palliative Interventions

• Venting gastrostomy tube for symptom relief when surgery is not possible 2, 7, 8
• Total parenteral nutrition for patients with life expectancy of months to years 2
• Home hydration with overnight 10% dextrose infusions through central venous catheters for terminal care 8

Critical Pitfalls to Avoid

• Never delay surgical consultation when peritonitis, fever, hypotension, or marked leukocytosis are present 2, 4
• Never use prokinetic antiemetics (metoclopramide) in complete obstruction 2
• Never proceed to surgery without correcting electrolyte abnormalities and adequate resuscitation 2
• Never rely on plain radiographs alone to exclude bowel obstruction (only 50-60% sensitive) 5
• Never administer water-soluble contrast before adequate nasogastric decompression 5

Disposition

All patients with bowel obstruction require surgical service evaluation and hospital admission for either operative intervention or monitored non-operative management with serial examinations every 4 hours. 4, 6