Aspirin Overdose Flashcards
What is an Aspirin overdose?
Excessive ingestion of aspirin causing toxicity
Describe the aetiology of Aspirin overdose
Can be a result of deliberate self-harm, suicidal intent or by accident
What is the typical SBA clue for Aspirin overdose?
PMHx of TIA/ stroke so likely to be on aspirin + depression (OD)
Describe the epidemiology of Aspirin overdose
One of the MOST COMMON drug ODs
People at extremes of ages (e.g. < 3yrs or >70yrs) = particular risk of incorrect dosing
List 8 early symptoms of Aspirin overdose
Flushed Sweating Dizziness Malaise Tinnitus/ Deafness N+V Haematemesis Epigastric pain
List 6 signs of Aspirin overdose
Kussmaul's breathing Fever Tachycardia Hyperventilation Epigastric tenderness Asterixis/ stupor/ movement disorders
What bloods are necessary in Aspirin overdose?
Salicylate levels
FBC: WBC elevated but non-specific
U+Es: check for hypokalaemia; urea + cr levels may be deranged if renal insufficiency
LFTs: high AST/ALT due to direct hepatotoxicity
Clotting screen: high PT
Other drug levels (e.g. paracetamol)
Describe what may be seen on ABG in Aspirin overdose
Mixed Respiratory alkalosis (increased resp drive so blow off CO2) Metabolic acidosis (lactic acid buildup)
What is the treatment for Aspirin overdose?
IV fluids
Sodium Bicarbonate
What may be seen on ECG in Aspirin overdose?
Signs of hypokalaemia: Flattened/ inverted T waves U waves Prolonged PR interval ST depression
List 6 late symptoms of Aspirin overdose
Lethargy Confusion Convulsions Drowsiness Respiratory depression Coma
What key facts should be established about the aspirin overdose?
How much aspirin was taken?
When was it taken?
Were any other drugs taken?
Have you had any alcohol?
Describe levels of Aspirin causative of toxicity
10-20 g can cause moderate-severe toxicity in adults 150mg/kg: mild toxicity 250mg/kg: moderate >500mg/kg: severe >700mg/kg: potentially fatal
Describe the pathophysiology of Aspirin overdose
Increases RR + depth by stimulating the respiratory centre
Hyperventilation –> respiratory alkalosis (early stage)
Body compensates by increasing urinary bicarbonate + K+ excretion
Leads to dehydration + hypokalaemia
Loss of bicarbonate, uncoupling of mitochondrial oxidative phosphorylation + the build up of lactic acid can lead to metabolic acidosis
In SEVERE cases, CNS depression + respiratory failure can occur
Describe the physiological properties of Aspirin and its absorption
Aspirin is a weak acid with poor water solubility
Is rapidly hydrolysed to salicylate in GIT + bloodstream