: Of the 8,000-10,000 snake envenomations evaluated in U.S. emergency departments (ED)
annually, approximately 1% are due to non-native snakes. We describe a 26-year-old
male who was bitten by his captive black mamba (Dendroaspis polylepis) as he was packing it up for transport to another snake collector.
: The patient presented to the ED one hour after being bitten on the forearm complaining
of left arm pain, oral paresthesias, and dyspnea. His vital signs: heart rate 96 beats/min,
blood pressure 167/101 mm Hg, temperature 36.7°C (97.9°F), respiratory rate 20 breaths/min,
and room air oxygen saturation 100%. Two mildly tender puncture wounds without swelling
or ecchymosis were found on the posterior aspect of the forearm. Over the ensuing
30 minutes his dyspnea worsened, and he developed objective weakness. He was intubated
and placed on mechanical ventilation. He was treated with atropine 2 mg for bronchorrhea.
Five vials of South African Vaccine Producers (SAVP) polyvalent antivenom were administered
2.5 hours post-bite and the patient was admitted to the intensive care unit. He was
extubated 18 hours post-envenomation and discharged the following day. He has remained
asymptomatic since leaving the hospital.
Why should an emergency physician be aware of this
: The primary manifestations of Dendroaspis polylepis envenomings are neurological. Initial signs may include paresthesias, dysarthria,
dysphagia, and ptosis. Progressive descending paralysis leading to respiratory failure
develops within 60 minutes. Muscarinic features are frequently observed. Cardiotoxicity
and hematologic laboratory abnormalities may be present. Although pain is common,
significant local tissue injury does not occur. In addition to supportive care, several
non-native antivenoms are indicated for D. polylepis envenomations.
: Black mamba envenomings differ from the native snakebites with which U.S. physicians
are familiar. Rapid, progressive neurological toxicity and muscarinic features are
most common. Treatment consists of supportive care and appropriate antivenom administration.