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Case 8.4 – LBO [SDL]

Category: Surgery | Discipline: Surgery - GIT | Setting: Emergency Department

Case

Harper Taylor, aged 68 yrs, presents with abdominal distension and pain that is cramping in nature. He has been feeling nauseated for 2 days and has vomited bile stained foul smelling liquid for 24 hours. He appears pale and unwell and has marked halitosis.

Questions

1. What further history & examination would you undertake?

History and Examination Approach:

  • Routine GIT history - including:
    • Bowel habit changes (constipation, diarrhea)
    • Previous episodes of obstruction
    • Weight loss, appetite changes
    • Previous abdominal surgery
    • Change in stool caliber (pencil-thin stools suggest colonic obstruction)
    • Rectal bleeding or melena
    • Family history of colorectal cancer
    • Past medical history (diverticular disease, inflammatory bowel disease)
  • GIT examination - including:
    • Inspection: distension, visible peristalsis, scars
    • Palpation: tenderness, guarding, rebound, palpable masses
    • Percussion: tympany suggests gas-filled loops
    • Auscultation: high-pitched bowel sounds, rushes and gurgles
    • Digital rectal examination (essential)
    • Hernial orifices examination

Important Note: 10% to 15% of intestinal obstruction in adults is the result of obstruction of the large bowel. The most common anatomic site of obstruction is the sigmoid colon.

2. An abdominal series X-ray demonstrate massive colonic distension. What are the likely causes for the obstruction?

Causes of Large Bowel Obstruction:

Mechanical Causes:

  • Adenocarcinoma (80-85%) - most common cause of colonic obstruction
    • Typically affects sigmoid colon and left colon
    • Presents with progressive symptoms
  • Scarring associated with diverticular disease (5-10%)
    • Chronic inflammation leads to stricture formation
    • Usually in sigmoid colon
  • Volvulus (5-10%)
    • Sigmoid volvulus (80% of volvulus cases)
    • Caecal volvulus (20% of volvulus cases)

Functional Causes:

  • Pseudo-obstruction (Ogilvie's syndrome)
    • Massive colonic dilatation without mechanical obstruction
    • Associated with electrolyte abnormalities, medications, or serious illness
3. How does colonic obstruction typically present?

Clinical Presentation of Colonic Obstruction:

  • Cramping abdominal pain
    • Colicky in nature
    • Comes in waves as peristalsis attempts to overcome obstruction
  • Nausea & vomiting
    • Late sign in colonic obstruction (unlike small bowel obstruction)
    • Vomitus may be feculent or bile-stained
  • Obstipation
    • No passage of flatus or stool for >12 hours
    • Absolute constipation is a hallmark feature
  • Abdominal distension
    • Often marked and progressive
    • May be asymmetric
  • Palpable mass
    • May represent distended bowel or tumor
  • Tympany on percussion
    • Due to gas-filled distended colon
  • High pitched metallic rushes & gurgles
    • Characteristic bowel sounds
    • May become absent if bowel becomes ischemic
4. Outline the management of colonic obstruction.

Management of Colonic Obstruction:

Management depends on whether the obstruction is partial (some lumen persists on CT) or complete.

Partial Obstruction - Conservative Management May Include:

  • Nasogastric decompression
    • Relieves nausea and vomiting
    • Prevents aspiration
  • Intravenous fluids with correction of electrolyte abnormalities
    • Patients often significantly dehydrated
    • Correct hypokalemia, hyponatremia
  • Decompression
    • Sigmoidoscopy (rigid or flexible) and placement of rectal tube
    • Particularly useful for sigmoid volvulus
  • Placement of stent
    • May allow more time for definitive surgery to be performed at a later date
    • Converts emergency to elective procedure
    • Allows bowel preparation and optimization of patient

Emergency Surgery Indications:

Emergency laparotomy is undertaken for acute large bowel obstruction with:

  • Caecal distension beyond 12 cm
  • Severe tenderness
  • Evidence of peritonitis
  • Generalized sepsis
  • Failed conservative management

Important Consideration - Ileocaecal Valve:

Competent or incompetent ileocaecal valve?

  • If competent ICV with mechanical obstruction in colon, creates a closed loop obstruction
  • This is particularly dangerous as the caecum (widest part, thinnest wall) is at highest risk of perforation (Law of LaPlace)
  • If incompetent valve, small bowel also dilates, reducing risk of caecal perforation but causing small bowel symptoms
5. What is volvulus of the large intestine & what risk factors have been identified for this condition?

Definition and Sites:

  • Volvulus is rotation of a segment of the intestine on the axis formed by its mesentery
  • Results in obstruction and potential vascular compromise

Most Common Sites in Large Bowel:

  • Sigmoid colon (80%) - most common site
    • Occurs when sigmoid colon is redundant with narrow mesenteric base
    • Allows twisting around mesenteric axis
  • Caecum (20%)
    • Occurs when caecum is mobile
    • Due to incomplete embryological fixation

Risk Factors for Sigmoid Volvulus:

  • Chronic constipation
  • High fiber diet (redundant colon)
  • Neurological/psychiatric conditions
  • Institutionalized patients
  • Medications causing constipation (opiates, psychotropics)
  • Chagas disease (in endemic areas)
  • Elderly patients
  • Previous episodes of volvulus

Risk Factors for Caecal Volvulus:

  • Congenital failure of peritoneal fixation of right colon
  • Previous abdominal surgery with adhesions
  • Pregnancy
  • Younger age group compared to sigmoid volvulus
6. How does volvulus present clinically?

Clinical Presentation of Volvulus:

  • Abdominal pain
    • Sudden onset
    • Severe, constant pain
    • May have colicky component initially
  • Vomiting
    • May be early or late depending on site
    • Can be bilious or feculent
  • Obstipation
    • Absolute constipation
    • No passage of flatus or stool
  • Abdominal distension (often massive)
    • Can be dramatic, especially in sigmoid volvulus
    • May have visible asymmetry
  • Tympany on percussion
    • Grossly tympanic abdomen
  • High-pitched tinkling sounds & rushes
    • Early in presentation
    • May progress to absent bowel sounds if ischemia develops
  • Tachypnoea
    • Due to pain and distension restricting diaphragmatic movement
    • May indicate development of ischemia or perforation

Warning Signs of Strangulation:

  • Severe constant pain
  • Peritonism (guarding, rebound tenderness)
  • Tachycardia, hypotension
  • Fever
  • Absent bowel sounds
7. What are the X-ray features of colonic obstruction?

Plain Film (Abdominal X-ray) Findings:

General Features of Colonic Obstruction:

  • Distended proximal colon
    • Proximal to point of obstruction
    • Colon identified by haustral markings (incomplete, do not cross entire lumen)
  • Air-fluid levels
    • Seen on erect or lateral decubitus films
    • Less prominent than in small bowel obstruction
  • No distal rectal air
    • Empty rectum on plain film suggests complete obstruction
  • Caecal diameter
    • Diameter >9 cm indicates significant distension
    • Diameter >12 cm indicates high risk of perforation - urgent surgery required

Specific Findings in Sigmoid Volvulus:

  • "Coffee bean" sign or "bent inner tube" sign
    • Massively dilated sigmoid loop
    • Inverted U-shape with apex usually in right upper quadrant
  • "Bird's beak" sign
    • Point of torsion appears tapered
    • Best seen on contrast enema
  • Loss of haustral markings in twisted segment

Specific Findings in Caecal Volvulus:

  • Massively dilated caecum
    • May be displaced to left upper quadrant or epigastrium
  • "Coffee bean" appearance
    • With apex pointing to left upper quadrant
  • Small bowel dilatation may be present

Further Imaging:

  • CT abdomen/pelvis with contrast - gold standard
    • Identifies site and cause of obstruction
    • "Whirl sign" in volvulus (twisted mesentery and vessels)
    • Can identify ischemia, perforation, or mass lesion
    • Determines competence of ileocaecal valve
  • Contrast enema
    • Water-soluble contrast (gastrografin)
    • Shows "bird's beak" at point of obstruction
8. What is the treatment of volvulus?

Management of Volvulus:

Sigmoid Volvulus:

Initial Management (if no signs of strangulation/perforation):

  • Sigmoidoscopy with rectal tube insertion is the recommended initial treatment
    • Can be performed with rigid or flexible sigmoidoscope
    • Success rate 70-80% for decompression
    • Passage of large volume of flatus and liquid stool indicates success
    • Rectal tube left in place for 24-48 hours
  • Resuscitation
    • IV fluids
    • Correction of electrolyte abnormalities
    • NGT decompression

Definitive Surgery for Sigmoid Volvulus:

  • Emergency operation is performed promptly if:
    • Strangulation or perforation is suspected
    • Attempts to decompress the bowel are unsuccessful
    • Signs of peritonitis
  • Emergency surgery involves:
    • Resection without anastomosis (Hartmann's procedure)
    • Construction of an end colostomy
    • Performed if bowel is gangrenous or patient unstable
  • Elective surgery for recurrent sigmoid volvulus
    • Usually sigmoid colectomy with primary anastomosis
    • Performed after successful non-operative decompression
    • High recurrence rate (40-60%) if not resected

Caecal Volvulus:

Always treated surgically (endoscopic decompression unreliable)

  • In a frail patient:
    • Caecopexy - suturing the caecum to the parietal peritoneum
      • Lower risk procedure
      • Only if caecum is viable
      • High recurrence rate
  • If caecum is gangrenous OR patient able to safely tolerate surgery:
    • Right hemicolectomy with ileocolic anastomosis
      • Definitive treatment
      • Low recurrence rate
      • Preferred option when feasible

Key Principle: Never delay surgery if there are signs of ischemia or perforation. Early surgical intervention improves outcomes significantly.