OzEMedicine - Wiki for Australian Emergency Medicine Doctors

see also colchicine, toxicology

• death from as little as 7mg, survival with ingestions as large as 350mg
• survival usual with doses < 0.5mg/kg (ie. low therapeutic index!!)
• death almost certain with doses > 0.8mg/kg

• within hours:
  • GIT toxicity:
    • ⇒ nausea, vomiting & profuse watery diarrhoea +/- bloody diarrhoea
    • ⇒ burning throat pain
    • ⇒ ileus
  • other organ toxicity as below may occur
• 24-48hrs:
  • cardiovascular collapse:
    • fluid loss - diarrhoea, third space
    • electrolyte, acid-base derangements
    • endotoxaemia from GIT mucosal dysfunction
    • direct cardiac toxicity:
      • impaired sarcoplasmic reticular function
      • decreased calcium myofilament sensitivity
      • altered cross-bridge kinetics
      • myothermal economy
      • cardiac conduction abnormalities:
        • bradycardia
        • varying degrees of AV block
        • sinus arrest
      • elevated cardiac enzymes in severe cases
  • renal dysfunction:
    • haematuria is almost invariable +/- oliguria, resulting from:
      • hypotension
      • sepsis
      • myoglobinuria
      • direct nephrotoxicity
  • respiratory failure (30% pts, & may occur suddenly) which may be due to:
    • aspiration
    • cardiac failure
    • massive transfusion
    • direct pulmonary vascular injury
    • resp. muscle weakness
  • metabolic disturbances:
    • acidosis
    • syndrome of inappropriate ADH secretion (SIADH) (20-30% of pts)
    • hypokalaemia
    • hypomagnesaemia
    • hypocalcaemia
  • neuromuscular:
    • muscle weakness
    • depressed tendon reflexes
    • papilloedema, transverse myelitis, ascending paralysis, altered mental state (incl. coma)
• several days - 1 week:
  • bone marrow failure - the major cause of late fatalities
  • alopecia (mat persist for several months)

• ABC's
• IV line, fluids to prevent hypovolaemia
• bloods taken for: FBE, clotting, U&Es, LFTs (repeat all at 6hrs)
• bloods for se paracetamol level if co-ingestion possible (otherwise urinary drug screen)
• activated charcoal if no ileus
• if presentation within 1hr with substantial ingestion or symptomatic
  • ⇒ consider gastric lavage
  • ⇒ repeat activated charcoal 4hrly if no ileus in view of enterohepatic circulation
  • ⇒ consider early central/arterial lines to assist monitoring of BP, CVP
• supportive care as indicated
• Rx haematologic toxicity as indicated:
• Rx consumptive coagulopathy with:
  • blood component replacement
  • consider:
    • DDAVP to improve platelet release reaction
    • aminocaproic acid as an antifibrinolytic
  • Rx bone marrow hypoplasia:
    • G-CSF
  • take precautions to minimise infection risk
• theoretically, Fab fragments specific for colchicine may be of help but are still not available, & the French researchers who developed it have recently abandoned plans to make them commercially available
• NOT USEFUL:
  • forced urine alkaline diuresis
  • haemodialysis/heamoperfusion

• adults asymptomatic (ie. no GIT toxicity) for 8hrs post-ingestion & normal repeat laboratory tests at 6hrs, can be medically cleared, otherwise admit +/- ICU

• Harris RD Gillett MJ Colchicine poisoning - overview & new directions Emergency Medicine June 1998 10(2):161-7