Aspirin Overdose Flashcards
Define aspirin overdose
Taking too much (>125mg/kg) of salycilate, or any exposure to methyl salicylate
500mg/kg is severe. over 700mg/kg fatal
can be because of acute intake or a chronic long term one
technically salicylate poisoning, which aspirin contains
Aetiology and risk factors of aspirin overdose
The main source of salicylate is aspirin (but can be found in small amounts in plants)
Other sources can be in cold and flu medication-patients might not recognise its there
Finally can be found in some anti-diarrhoea medication
Some oils have salicylate which can enter cutaneously-methyl salicylate is bad
pathophys
Overdose overload liver enzymes, causing accumulation. 30% is excreted in Urine, but with kidney fail and/or acidosis-bad (acidosis causes it to lose ion and reabsorb)-the non-ionised can cross the BBB and cause neuro issues
The rest interfere with Metabolism (kreps cycle)
and uncouple OxPhos-> metabolic acidosis
also cause fever, and resp alkalosis (which feeds metabolic acidosis more)
Risk factors-suicidal, very young, very old
Symptoms and signs of aspirin overdose
UNLIKE paracetamol-early signs
Vomiting, dehydration
Hyperventilation, HEAT/Pyrexia
TINNITUS and vertigo
usually present with resp alkalosis
AND then gets metabolic acidosis as salicylates and AKI set in
Rarer-Lower GCS, Seizure, lower bP, heart block, Pulm oedema, coma
the more severe the initial dose, the more the rarer signs occur
Investigations for aspirin overdose
ABG-want to know all about p02, pCO2, Base excess and bicarb
=> result of mixed alk or acidosis
EARLY- RESP ALK, then onto Metabolic acidosis
Plasma salcylate-hIGH
Metabolic acidosis is associated with increased mortality
U&E-potasium and bicarb low
glucose might be high or low
INR/APTT/PT-raised
Management of aspirin/salycilate poisoning?
General A-E approach
CHARCHOAL in first hour as always
urinary alkalinization with intravenous sodium bicarbonate - enhances elimination of aspirin in the urine
Heamodyalisi
if- Conc >700, MEtabolic acidosis resistant
AKI, pulm oedema, seizure etc
