Cyanide Poisoning

Sources: • Smoke inhalation (house fires, plastic / wool combustion). • Industrial: mining, plating, jewellery (potassium cyanide). • Suicide. • Apricot kernels, cassava, almond seeds (amygdalin). • Sodium nitroprusside infusion (prolonged / high-dose). Features: • ALOC, headache, vertigo. • Cardiovascular: tachycardia → bradycardia → cardiac arrest. • Severe metabolic acidosis with raised lactate. • 'Cherry-red' skin (not reliable; classic teaching). • Almond breath (only ~50% can detect). • Bitter almond smell on breath. Workup: ABG (raised lactate >8 mmol/L in smoke inhalation strongly suggests cyanide), VBG (high venous O₂ saturation — tissues unable to use O₂), COHb (often co-existing CO poisoning).