Bowel Obstruction

Bowel Obstruction Epidemiology Common reason for admission Accounts for 15% of abdominal pain related admissions Patients may be presenting for something else Small bowel obstruction is more common than large bowel obstruction Key Info Not all constipation is obstruction Need to differentiate between obstruction and constipation May be partial or complete Closed loop obstruction Obstruction at two different points along the same loop of bowel Causes MECHANICAL – MORE COMMON Luminal – within the lumen Mural – within the wall Extrinsic – outside the wall Adhesions Rarely without previous surgery Congenital Tumours Bands Primary: carcinoma, lymphoma and sarcoma Malrotations Foreign bodies Secondary: melanoma Acquired Inflammatory strictures Post-surgical IBD, diverticulitis Inflammatory Radiation enteropathy Neoplastic Gallstone ileus Faecal impaction Chemical, pharmacological Hernias Volvulus FUNCTIONAL/PSEUDO-OBSTRUCTION Infection and sepsis Injury or physical trauma Postoperative Neurological: Parkison’s disease, Alzheimer’s disease, Multiple Sclerosis Medications: opiates, anti-depressants, NSAIDs, KCl Metabolic: electrolyte imbalance, diabetic ketoacidosis Cardiovascular disease: MI, HF and stroke Small Bowel Obstruction vs Large Bowel Obstruction Small Bowel Large Bowel Usually due to post-surgical adhesions Common causes are colorectal cancer (most common) and diverticulitis Clinical features Clinical features Bloating Early nausea and vomit Constipation Central colicky pain Lower abdominal pain/distension Bowel dilation of more than 3 cm Bowel dilated more than 6cm and more than 9cm if at caecum Coin stacking appearance on ABX Loss of haustra on ABX Clinical Features History Physical Exam Abdominal distension Abdominal tenderness Colicky and cramp like abdominal pain High-pitched or tinkling sounds Abdominal bloating Early in obstruction Nausea and vomit Absent bowel sounds Constipation Late in obstruction Obstipation Evidence of underlying cause Fluid losses and third spacing Scars from previous surgery Obvious hernia Investigations Vitals Bloods FBC: leucocytosis Urea and electrolytes: vomit -> renal function and electrolyte disturbances CRP and lactate -> bowel ischemia Blood cultures Group and hold Imaging Abdominal X ray First line imaging SBO vs LBO SBO LBO Central Peripheral Diameter: >3 cm Diameter: colon >6cm and caecum > 9cm Valvulae conniventes Loss of haustra Minimal intraluminal gas Mixture of gas and faeces Air fluid levels Air fluid levels? Pneumoperitoneum or pneumomediastinum if perforation occurred Pneumoperitoneum or pneumomediastinum if perforation occurred CT abdomen and pelvis with IV contrast Gold standard investigation Dilated loops proximal to blockage Collapsed loops distally Transition point = obstruction Air fluid levels Apple core Teeth bite marks -> tumor Features of strangulation: Bowel wall thickening Increased density Mesenteric fluid/congestion Pneumonitis Contrast studies Endoscopy Management INITIAL MANAGEMENT NPO Bowel rest-> reduce peristalsis Large bore cannulas IV fluids -> to correct fluid depletion NGT Bowel decompression Relieves abdominal distension Relieves vomit Reduces aspiration risk Urinary catheter Analgesia if septic or pre-operative DEFINITIVE MANAGEMENT Adhesions: water soluble study (gastrographin) Sigmoid volvulus: endoscopic decompression with flexible sigmoidoscopy Left sided bowel tumor: endoscopic stenting -> bridge to surgery or palliation Stricture: endoscopic dilation or stent placement Pseudo-obstruction : correct electrolyte abnormalities Discontinue anti-kinetic drugs and treat the underlying cause Surgery indicated when: Suspicion for intestinal ischemia or closed loop obstruction Complications Bowel ischemia Pain out of proportion Fever and tachycardia Most common Bowel perforation with peritonitis Incarceration Perforation with intra-abdominal abscess Severe abdominal pain, fever and possible palpable mass Sepsis & multiorgan failure Aspiration pneumonia Toxic megacolon