A venomous visitor from the tropics

CASE PRESENTATION A 54-year-old man presented to the emergency room following a scorpion sting to the right index finger. He had been unloading a shipment of mangoes from South America and noted a small scorpion in the box, which he picked up and then killed after the sting (Figure 1A). Following the envenomation, he experienced acute paresthesia localized to the right arm, up to the elbow. He reported no fasciculations, spasms, myoclonus or any other focal or generalized neurological symptoms at that time. Review of systems was otherwise unremarkable. Medical history was only remarkable for a remote smoking history. He was on no regular medications and had no known drug allergies. On initial examination, he was afebrile, with a blood pressure of 125/70 mmHg sitting, heart rate of 70 beats/min, oxygen saturation of 98% on room air and a respiratory rate of 20 breaths/min. He was in no apparent distress. The distal interphalangeal joint of his right finger was swollen and erythematous, with an obvious puncture mark present. No sensory or motor abnormalities were noted, and reflexes were normal in the right upper extremity. No lymphadenopathy was noted. Cardiovascular, respiratory and abdominal examinations were all within normal limits. Initial white blood cell count was 10.1×109/L, hemoglobin 144 g/L and platelets 317×109/L. Sodium was 139 mmol/L, potassium 3.9 mmol/L, chloride 106 mmol/L and bicarbonate 24 mmol/L. Creatinine was 66 μmol/L, aspartate transaminase 22 U/L, alanine transaminase 31 U/L, alkaline phosphatase 110 U/l, total bilirubin 3 μmol/L, creatinine kinase 155 U/L and lipase 114 U/L. In the emergency room, he was monitored for 5 h with no progression of upper extremity paresthesia. Local poison control was contacted, but believed that antitoxin was not needed. The patient was discharged home with symptomatic management, including nonsteroidal anti-inflammatory drugs. He was assessed as an outpatient 24 h later, and experienced regression of paresthesia to the wrist and had developed significant spasms in his right hand. He was prescribed benzodiazapines for symptomatic management, with resolution of his symptoms. He was assessed a few weeks following the envenomation and had some residual paresthesia localized to the bite site without any other sensory symptoms or muscular spasms.