Clinical presentation of sympathomimetic toxidrome

Features of a sympathomimetic toxidrome are caused by the relative effects of the implicated drug on synaptic neurotransmitter concentrations, mainly dopamine, noradrenaline and serotonin. Many of these effects can be life threatening.

Effects of sympathomimetic drugs include:

• cardiovascular effects
  • tachycardia, arrhythmias
  • hypertension; if severe, can cause aortic or carotid dissection, or mesenteric ischaemia
  • acute coronary syndrome, myocardial ischaemia or infarction
  • hypotension (with severe sympathomimetic toxidrome), myocardial depression, pulmonary oedema
• central nervous system (CNS) effects
  • excitation—anxiety, euphoria, agitation, tachypnoea, delirium, seizures
  • acute behavioural disturbance mainly with amfetamines—aggression, violence, psychosis
  • thrombotic and haemorrhagic strokes, intracranial haemorrhage
• neuromuscular effects—hyperreflexia, tremor
• autonomic effects
  • hyperthermia (temperature more than 39ºC or rapidly rising); if severe, can cause multiorgan failure
  • sweating, flushing, pallor, mydriasis
• metabolic effects—hypokalaemia, hyperglycaemia, lactic acidosis
• gastrointestinal effects—nausea, vomiting, diarrhoea
• other effects
  • rhabdomyolysis, occasionally causing secondary kidney failure
  • respiratory barotrauma (eg pneumothorax) due to Valsalva manoeuvre during smoking.