Pt has leg weakness after trip into woods. What is a rare cause of the patient's presentation which can be diagnosed and easily treated in the ED?

Tick paralysis.

Picture of a tick; so you know what your lookin' for

Other factoids:

Incidence: super rare. The incidence of Guillain-Barre syndrome (GBS) which is 1 - 2 per 100,000 people per year is about 10 - 12 times that of tick paralysis.

Distribution: North America (more on West side) and Australia

Mechanism: tick's salivary toxins have deleterious effect on peripheral nerve conduction

Presentation: very similar to GBS except onset of ascending paresthesias and weakness often faster (hour to 1-2 days relative to several days to a week), CSF analysis normal

Treatment: remove tick.


Sources

Image source: http://www.pestcontrolrx.com/photos/uncategorized/2008/09/02/deertick.jpg

Sexton, D. et al. "Tick paralysis" Up to Date. 8 September 2006.