Makindo Medical Notes

Related Subjects: |Small Bowel Obstruction |Colonic (Large bowel) Obstruction |Caecal Volvulus |Small Bowel Ischaemia |Hartmann's procedure |Sigmoid Volvulus |Acute Colonic Pseudo-obstruction

The acute use of an anticholinesterase such as neostigmine has been shown to cause rapid resumption of normal activity, adding weight to the aetiological theory of autonomic nerve dysfunction. Decreased parasympathetic tone vs increased sympathetic tone of the left colon can cause functional obstruction. 🔑 Principles: exclude mechanical obstruction + decompress bowel + treat triggers.

🩹 Initial Medical Management
Nil by mouth, NG tube, rectal flatus tube. Correct electrolytes, hydration, posture adjustment. Stop exacerbating drugs (opioids, anticholinergics). Mobilise early, out of bed if possible. Close surgical review if worsening.

🚨 Acute Colonic Pseudo-obstruction (ACPO, Ogilvie’s Syndrome) mimics mechanical bowel obstruction but is due to impaired colonic motility. Elderly, comorbid, and immobile patients are at highest risk. Caecal perforation is the feared complication if not recognised early.

📖 About

• Clinical picture resembles mechanical large bowel obstruction.
• Functional obstruction due to autonomic dysregulation of colonic motility.

🧠 Physiology

• Two main ENS neurotransmitters:
  • ➡️ Acetylcholine → ↑ motility & secretions.
  • ➡️ Noradrenaline → ↓ motility & secretions.
• Excessive sympathetic activity & reduced cholinergic drive → bowel paralysis.

🩺 Aetiology

• Impaired bowel peristalsis → failure of intestinal motility.
• Loss of autonomic control (↑ sympathetic inhibition, ↓ parasympathetic tone).

⚠️ Risk Factors

• 👵 Elderly with comorbidities.
• Recent illness/trauma: MI, pneumonia, hip fracture, sepsis.
• Drugs: 💊 opioids, antidepressants, baclofen, anticholinergics.
• Endocrine/metabolic: hypothyroid, electrolyte disturbance.
• Neurological/systemic: MS, SLE, myasthenia, amyloidosis, mitochondrial disease.
• Immobility, COPD, malnutrition.

👨‍⚕️ Clinical Features

• Abdominal pain, distension, nausea/vomiting.
• Failure to pass flatus PR, progressive abdominal girth.
• May resemble large bowel obstruction.

🔍 Differentials

• Mechanical colonic obstruction: tumour, adhesions, volvulus.

🧪 Investigations

• Bloods: FBC, U&E, Ca, glucose, TFT.
• AXR: colonic dilatation, caecal diameter (risk if >9 cm; perforation >14 cm).
• CT/contrast enema to exclude true obstruction.
• Colonoscopy sometimes used diagnostically (not always to caecum).

💥 Complications

• Caecal perforation (esp. if diameter >14 cm, untreated).
• Peritonitis, sepsis, death.

💊 Medical Therapy

• Prokinetics: Prucalopride (off-licence) 1–2 mg PO daily for refractory cases.
• Neostigmine: 2 mg IV over 5 min (repeat if no response). ⚠️ Risk of bradycardia → give under monitoring.
• Nutrition: prolonged course may need TPN (usually HDU/ICU).

🛠️ Interventional / Surgical

• Endoscopic colonic decompression if caecal diameter >9 cm or progressive distension.
• If impending perforation or ischaemia → surgical caecostomy or hemicolectomy.
• Despite advances, prognosis often poor in frail patients.

📚 References

• Acute Colonic Pseudo-obstruction (Ogilvie’s Syndrome) – Case review