evidence to recommend any treatment as effective Consultation with neurology and infectious disease is recommended Birth trauma may produce traction injuries to the nerve roots causing a restricted pattern of focal weakness Erb palsy, a proximal (C5/C6) brachial plexus palsy, is the most common brachial plexus injury These infants assume the “waiter’s tip” posture: arm adducted, humerus internally rotated, elbow extended, forearm pronated, wrist flexed Klumpke palsy , an injury to the lower trunk (C8/T1) of the plexus, is much rarer This typically manifests as an infant holding the arm in supination with the elbow flexed and wrist extended Fortunately, most birth-related traction injuries of the brachial plexus result in only a self-limited neuropraxia from stretching of the nerves, with resolution of symptoms by months of age More extensive brachial plexus injuries can be associated with Horner syndrome (ptosis, miosis, anhidrosis) due to injury of the stellate ganglion Avulsions or ruptures of the nerves usually result in more permanent weakness Flaccid weakness of the arms and legs may result from excessive traction on the spinal cord during a difficult delivery Heavy metals, such as lead, mercury, arsenic, and thallium, are known neuropathic toxins Lead, in particular, may cause a distal motor weakness with foot and wrist drop Drug-induced neuropathies occur with drugs of abuse, as well as pharmacologic medicines Several antimicrobials (isoniazid, nitrofurantoin, and zidovudine), as well as antineoplastics (vincristine, vinblastine, cytosine arabinoside, and cisplatin), are known to cause paresthesias and muscle weakness The seas also harbor deadly neurotoxins Ciguatera and paralytic shellfish poisoning are caused when toxin-elaborating dinoflagellates are ingested by fish or shellfish, which are then eaten by unsuspecting humans Cone snail stings, blue-ringed octopus bites, sea snake bites, and puffer fish ingestion may also result in life-threatening paralysis On land, the Crotalidae (pit vipers) and Elapidae (coral snakes) families of snakes in the United States are responsible for nearly 8,000 envenomations each year Pit viper bites initially cause localized pain, erythema, edema, and even tissue necrosis, but then severe multiorgan systemic symptoms, including weakness, may develop Coral snakes, on the other hand, have a paucity of local signs associated with their bites, but then weakness and severe neurotoxicity ensue A respiratory paralysis results from the toxin’s presynaptic neuromuscular blockade; this ultimately proves fatal in 10 to 20 human cases per year Acute intermittent porphyria is an autosomal dominant inborn error of metabolism that usually presents after puberty (women > men) with neurovisceral