Zika Update: How is Nantucket like Medellin, Columbia?
The answer to the question posed in the title is that you can get “bilateral Bell’s palsy” in both places. This answer begs for a bit of explanation . . .
Bell’s palsy is paralysis of the face. You may not know it, but Bell’s palsy is fairly common. (Fortunately, it is usually temporary.) Most Bell’s palsy is unilateral: one side of the face droops and a blink is incomplete. Sufferers may drool and must use lubricating eye drops frequently. Compared with unilateral Bell’s palsy, bilateral facial palsy is quite rare.
The most common cause of Bell’s palsy is reactivation of the herpes simplex virus, type I (HSV I). This is the same virus that will cause a fever blister after an infection such as the flu or unprotected sun exposure. When HSV I reactivates in the facial nerve, it is generally on one side (just like fever blisters), and that side of the face is paralyzed. (Taking acyclovir and prednisone can speed recovery.)
In the rare instances when Bell’s palsy is bilateral, the etiology is not HSV I. In the continental United States, this syndrome is due to Lyme disease. The medical term for this nearly unique etiology is “pathognomonic.” If you come back from Nantucket with bilateral Bell’s palsy, a good Infectious Disease specialist should be able to diagnose you from across the room.
A recent report found that half of 66 patients who suffered Guillain–Barré syndrome (GBS) after Zika virus infection had bilateral Bell’s palsy. There being no Lyme disease in Columbia, I expect that bilateral Bell’s palsy may be pathognomonic for preceding Zika virus infection if the victim is from Columbia. The time between the very first Zika symptom and the very first symptom of GBS was 1 week. (GBS usually starts on the legs and feet with numbness, tingling and weakness.)
Another interesting finding from this report is that almost all the patients had evidence of previous dengue virus infection (another flavivirus). This is called immune enhancement. That is, pre-existing antibodies to dengue predispose to the complications of Zika.
So, here’s a question for you that is worthy of the Infectious Disease Board examination. If a U.S. citizen from Nantucket, Massachusetts travels to Medellin, Columbia and then comes down with bilateral Bell’s palsy, what is she infected with? The answer is Borrelia burgdorferi, the Lyme disease bacteria. Tourists can certainly get Zika virus infections, but they are not likely to get GBS because it is probably their first exposure to a flavivirus.
Winkler G. Weinberg, MD