aspirin overdose Flashcards
definition of aspirin overdose
excessive ingestion of aspirin = toxicity
aetiology of aspirin overdose
deliberate self harm, suicidal attempt or be accident (children)
ingestion of 10-20g can = moderate to severe toxicity in adults
aspirin (acetylsalicyclate) increases RR and depth by stimulating the CNS resp centre
hyperventilation = resp alkalosis in the early phase
body compensates by increasing urinary bicarb and K excretion, causing dehydration and hypokalaemia
Loss of bicarbonate together with the uncoupling of mitochondrial oxidative phosphorylation by salicylic acid (= anaerobic metabolism) and build up of lactic acid can lead to metabolic acidosis.
in severe overdose - CNS depression and resp failure can occur
effects are dose related
epidemiology of aspirin OD
one of the most common drug OD
history of aspirin OD
get the key facts:
- How much aspirin
- when
- any other drugs
- have you had any other alcohol
symptoms of aspirin OD
may be asymptomatic initially
early:
- flushed
- fever
- sweating
- hyperventilation
- dizziness
- tinnitus
- deafness
- dehydration
- vomiting
- vertigo
late symptoms
- lethargy
- confusion
- convulsions
- drowsiness
- resp depression
- coma
rarely - low GCS, seizures, low BP, heart block, pul oedema, hyperthermia
signs of aspirin OD
fever
tachycardia
hyperventilation
epigastric tenderness
hyper/hypoglycaemia can occur
investigations for aspirin OD
blood
- salicyclate levels (500–750 mg/L is a moderate overdose; >750 mg/L is a severe overdose)
- FBC
- UE (particularly low K if vomiting)
- LFT - high AST/ALT
- clotting screen - high PT
- glucose and other drug levels eg paracetamol
ABG
- may show mixed metabolic acidosis and resp alkalosis
ECG
- signs of hypokalaemia - small T waves, U waves
