Emergency and Toxicologyniche
A 58-year-old farmer near Dubbo, New South Wales, felt a sharp scratch on his ankle while moving hay bales and briefly lost consciousness about ten minutes later. In the emergency department he is alert, with two small puncture marks above the ankle. There is no ptosis, diplopia or limb weakness, and his muscles are not tender. Investigations show: INR unrecordable, activated partial thromboplastin time >200 seconds, fibrinogen <0.3 g/L (reference 2.0–4.0), D-dimer 48 mg/L (reference <0.5), platelets 178 x 10^9/L (150–400) and creatine kinase 88 U/L (reference <170). Envenomation by which one of the following snakes is the most likely cause of this presentation?