Question 29

College answer

Syllabus topic/section:

2.1.6    Gastrointestinal Intensive Care /Gastro-intestinal motility syndromes: L2
2.1.21 Applied Pharmacology in Intensive Care / Gastrointestinal, Aperients and Laxatives

Discussion:  

Candidates demonstrated the standard required when they used the glossary definition of “assessment” - (i.e. history, examination and investigations) to formulate their answer. A list of clinical signs and investigations, without contextualising them with the relevant clinical findings, did less well. For example, “PR” should be qualified by considering the findings of the examination and how it will change or compliment management.

The glossary of terms is also a guide to the depth of information required. Part B is a “discuss” question and therefore candidates who wrote a list of management options without a discussion of the risks, benefits, contraindications and patient cohort applications achieved less marks. Candidates who were able to state the rationale for treatments, which strategies they would employ first and why, demonstrated the required standard in this area

Discussion

a) Assessment

• History
  • Last normal motion
  • Diet history
  • Risk factors:
    • Reduced mobility
    • Deep sedation
    • Heavy opiate use
    • Anticholinergic drug side effects
    • Calcium channel blockers
    • The use of paralysing infusions
    • Electrolyte disturbance, eg.hypokalemia hypercalcemia and hypomagnesemia
    • Dehydration, inadequate fluid resuscitation (or excess diuresis)
• Examination
  • Signs of bowel obstruction
    • Distension, tympanic percussion, peritonism
    • Abnormal or absent bowel sounds
    • Vomiting, high NG aspirates
  • PR: hard stool
• Investigations
  • Biochemistry: hypokalemia, hypercalcemia, inflammatory markers
  • ​​​​​​​Chest Xray: to rapidly exclude bowel perforation, looking for gas under the diaphragm
  • Abdominal Xray: dilated bowel loops
  • CT of the abdomen: findings: gaseous dilatation of the colon with no stricture, mass or clear transition point.​​​​​​​

b)

Discussion of management:

• Address risk factors
  • Electrolyte correction
  • Often insufficient as a sole strategy 
• Preventative and supportive strategies
  • Early nutrition, avoidance of volume depletion or overload, early mobility, extubation, avoidance of constipating pharmacology, de-sedation
  • Not always possible
• Aperients, laxatives
  • Stool softeners, bulk-forming laxatives
  • Few relatively benign side effects 
  • Effect may be limited or delayed
  • Ineffective in ileus
  • May worsen distension (eg. lactulose)
• Enemas
  • More effective than aperients
  • More invasive
  • Modest risk of injury/perforation/electrolyte disturbance
• Prokinetics (erythromycin, neostigmine)
  • More effective in combination with aperients
  • Non-trivial (eg. QT prolongation, bradycardia)
  • Risk of perforation with unrecognised bowel obstruction

An "outline your management" answer would look different:

• Specific

  • ​​​​​​​Correct underlying pathology

  • Address modifiable risk factors

• Supportive

  • Nil by mouth, if ileus; nasogastric tube on free drainage or low wall suction
  • Or, change feeds to a less concentrated variety
  • Correct electrolytes, restore volume
  • Mobilise the patient and sit them out of bed

• Pharmacological

  • Limit anti-motility medications, such as opiates and anticholinergic agents
  • Antagonise them: Oral or nasogastric naloxone, methylnaltrexone
  • ​​​​​​​Aperients/laxatives
  • Prokinetics: Erythromycin, neostigmine
  • Enemas

• Interventional (decompressive) management

  • Sigmoidoscopy
  • Colonoscopy 
  • Surgical decompression