A 32-year-old man is brought to the emergency department with progressive ascending paralysis that began 18 hours earlier. He initially noticed paresthesias in his lower extremities, followed by a sense of fatigue and weakness that was more pronounced in his left leg. He has no history of headache, fever, or recent infection or illness. He had just returned from a hiking trip to Colorado. His blood pressure is 122/81 mm Hg, pulse is 86/min, respirations are 16/min, and temperature is 37.3 C (99.2 F). Physical examination reveals intact cranial nerves, absent deep tendon reflexes in the left lower extremity and 1+ in the right lower extremity, and a normal sensory examination. Both lower extremities show weakness, with no motor activity in his left leg. Laboratory results show a normal WBC count. No abnormalities are noted on CSF examination. What is the most appropriate next step in the management of this patient?

Question

A 32-year-old man is brought to the emergency department with progressive ascending paralysis that  began 18 hours earlier.  He initially noticed paresthesias in his lower extremities, followed by a sense of fatigue and weakness that was more pronounced in his left leg.  He has no history of headache, fever, or recent infection or illness.  He had just returned from a hiking trip to Colorado.  His blood pressure is 122/81 mm Hg, pulse is 86/min, respirations are 16/min, and temperature is 37.3 C (99.2 F).  Physical examination reveals intact cranial nerves, absent deep tendon reflexes in the left lower extremity and 1+ in the right lower extremity, and a normal sensory examination.  Both lower extremities show weakness, with no motor activity in his left leg.  Laboratory results show a normal WBC count.  No abnormalities are noted on CSF examination.  What is the most appropriate next step in the management of this patient?

Quizplus · Accepted Answer

The most likely diagnosis is tick-borne paralysis. Patients usually present with progressive ascending paralysis over hours to days. Paralysis may be localized or more pronounced in 1 leg or arm, as in this patient. Fever is typically not present; hence, a history of fever or prodromal illness makes the diagnosis unlikely. Sensation is usually normal. There is no autonomic dysfunction noted in these patients, unlike that seen in the majority of patients with Guillain Barré syndrome (GBS). The CSF examination is typically normal. The etiology of the paralysis is neurotoxin release; the tick needs to feed for 4-7 days for the release of neurotoxin. Meticulous search for ticks in these patients usually reveals a tick, and removal usually results in improvement within an hour and complete recovery after several days. (Choice A) GBS presents with an ascending symmetrical paralysis over days to weeks, but not usually hours. Sensation is usually normal to mildly abnormal. Autonomic dysfunction (eg, tachycardia, urinary retention, and arrhythmias) occurs in 70% of patients. The CSF examination is typically abnormal and may show albuminocytologic dissociation (high protein with few cells). This finding may not be present early in the course of the disease but is present in 80-90% of patients at 1 week. Treatment includes IV immunoglobulin or plasmapheresis. GBS can be difficult to differentiate from tick paralysis in certain cases; however, meticulous search for a tick is very easy to perform. If a tick is found, extensive workup and unnecessary treatment can be avoided. (Choice B) Botulism presents with descending paralysis and early cranial nerve involvement. Pupillary abnormalities are common in botulism but rare in tick paralysis. (Choices C & E) Spinal cord tumors may also present with an ascending paralysis over days to weeks, but usually not hours. Sensation is either mildly or grossly abnormal. MRI of the spine is used to confirm the diagnosis. The treatment includes IV steroids (eg, methylprednisolone). Educational objective: Tick-borne paralysis is characterized by rapidly progressive ascending paralysis (which may be asymmetrical), absence of fever and sensory abnormalities, and normal CSF examination. Ticks must feed for 4-7 days and are typically found on patients after meticulous searching. Removal of the tick results in spontaneous improvement in most patients. References: Tick paralysis. (http://www.ncbi.nlm.nih.gov/pubmed/20842579) Tick paralysis. (http://www.ncbi.nlm.nih.gov/pubmed/18755381)

A 32-Year-Old Man Is Brought to the Emergency Department with Progressive