Causes:
Toxic Megacolon (C-diff, UC)
Mechanical Obstruction (Volvulus, CA, diverticulitis)
Acute Colonic Pseudo-obstruction
Colonic Pseudo-obstruction aka Olgilvie’s Syndrome
Diffusely dilated colon in absence of anatomic obstruction
Predisposing factors
1986 review of 400 cases; 95% with recognized predisposing factors - most with contributing factors of opiods, anticholinergic meds:
- Acute medical conditions (30%) - electrolyte abnormalities, respiratory failure, renal failure
- Non-op trauma (11%)
- Infection (10%)
- CHF or MI (10%)
- Post Abd/Pelvic Surgery (10%)
- Neurologic abnormality (10%) - parkinson's disease, spinal cord injury, MS, alzheimer's disease
- S/P Ortho procedure (7%)
Original description – 2 pts with retroperitoneal CA
1992 review: 52% with spine or retroperitoneal trauma or surgery, 20% with prior non CABG CT surgery
Pathophysiology
Incompletely understood (different than ileus, no SB involvement)
PNS suppression / SNS stimulation (especially S2-5)
Presentation -
Often Asxic; N, V, Obstipation or Diarrhea; Abdominal distension;
Increases risk of sigmoid volvulus;
15% overall mortality (40% if ischemia develops)
Diagnosis
Clinical presentation
Plain XRs, gastrograffin enema, endoscopy
Cecum > 10-12cm --> at risk for perferation especially with acute onset (risk varies based on how quickly cecum dilates)
MUST RULE OUT MECHANICAL OBSTRUCTION (usually with gastrograffin enema - secures diagnosis, rules out obstruction, can be therapeutic)
Medical Management
NPO, correct fluid and electrolyte imbalances, NG suction, rectal tube to gravity drainage (can be obstructed), limit offending meds, frequent position changes and ambulation if possible
70-90% resolve with conservative management
Indications for additional treatment
Failure to improve with 72 hr of treatment
Cecum > 12 cm, TC > 8 cm
Worsening status
Neostigmine Use
First line therapy in absence of peritonitic signs or significant evidence of ischemia
2 mg IV over 5 minutes
Leads to passage of flatus / stool within 5 minutes in 90%.
Side effects: Bradycardia (perform on tele, use atropine PRN, can be life threatening), airway secretions (premedicate with glycopyrrolate), bronchospasm, abdominal cramping, nausea, feeling weird/doom
Adverse events: Transient Abdominal Pain – 68%, Excessive Salivation – 44%, Vomiting – 11%, Symptomatic Bradycardia – 11%, Syncope – 5%,
Recurrence rate = 5 – 30%
Treat like a procedure: consent, monitor, laying down on bedpan, correct ‘lytes, stop anti-motility agents
Consider premedicating: Glycopyrrolate 0.4 mg IV (if worried about salivation)
Have atropine at bedside (dose is 0.5 mg)
May redose after 24 hr
Alternative regimens: 0.4-0.8 mg/hr IV drip x 24 hrs; 2 mg IVPB over 1 hr
Late Recurrence - Uncommon, 6 or 7 days or later
Recurrence should prompt consideration of:
Adult hirschsprung's disease (diagnosed with manometry and submucosal biopsy),
Paraneoplastic syndrome (most likely 10 = small cell CA), can evaluate with anti-neural nuclear antibody (ANNA 1) serology
1999 prospective, double blind, placebo controlled trial of 21 patients with CPO & cecum > 10 cm who failed 24 hr of medical managment in which mechanical obstruction ruled out and excluding pts with HR < 60, SBP < 90, peritoneal si, free air, bronchospasm, prior colon resection, Cr > 3
Randomized to 2 mg Neostigmine IV over 5 min VS saline
Demonstrated good response - median time to response = 4 minutes (range 3 - 30)
Endoscopic Decompression
60-80% success rate (not as successful as neostigmine)
20-50% require > 1 session
3-5% complication rate
Ideally get scope to proximal transverse colon, fluoro helpful if possible
Neostigmine Salvage
Proctoscopic Decompression
Endoscopic Cecostomy
Both R & L sided perc. Colon tubes described
? Evolving role
Fairly high comp. rate
Not ready for prime time in adults
Operative Management
Associated with 30% mortality
Cecostomy, Colostomy (left sided), Colectomy
CPO Algorithm: acute massive colon dilation --> exclude mechanical obstruction, assess for ischemia/perferation --> conservative management for 24-48 hrs, identify and treat reversible causes --> if no resolution or cecum >12 cm or distention > 3days --> IV neostigmine --> if recurrence or partial response redose --> no improvement then colonoscopy with decompression tube --> no improvement --> percutaneous cecostomy or surgery
Volvulus
Stomach, colon, small bowel can all twist causing volvulus
Torsion of bowel on its mesentery to a degree sufficient to cause sxs of obstruction (from narrowing lumen) or ischmia (from strangulation of blood supply)
2 Predisposing Factors: segment of redundant bowel, fixed point around which rotation can occur
5% of all bowel obstructions
10% of Large Bowel Obstructions: 1. CA, 2. Diverticulitis, 3. Volvulus
Location: Sigmoid 60-80%, Cecal 20-40%, Transverse 3%
Sigmoid Volvulus
60–80% of colonic volvulus cases
Typically see in elderly/debilitated
Twist is usually counterclockwise
Dx: Bent Inner Tube on plain XR; Bird’s Beak on barium enema --> therapeutic in 5%
Treatment: If peritonitic --> OR, otherwise decompression
Non-Op Treatment: proctoscope or flexible endoscopy has 90% success rate, can leave tube in for 48 hours, 50% recurrence rate
Op Management:
Sigmoid Colectomy
Subtotal Colectomy - 36% recurrence rate with proximal megacolon and sigmoid colectomy
Risk factors for poor outcome: old age, emergency surgery, history of recent volvulus, non-viable intestine
8% mortality with delayed resection after decompression
12% mortality in acute surgery without bowel infarction
25% mortality in acute surgery with infarction
Cecal Volvulus
20-40% of volvulus
See in younger pts
Predisposing causes: Mesenteric adenitis (traction), ileus (esp. patients with loose mesocolon), mechanical ventilation, colonoscopy, jogging
Cecal Bascule - Variant of Cecal volvulus
Diagnosis: Large air filled loop of colon - may be in LUQ with "empty RLQ sign", concurrent SB dilation seen
Treatment: Detorsion + Cecopexy + Cecostomy or just do the R hemicolectomy