POD- Lyme Disease Prophylaxis

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LYME DISEASE: When to give prophylaxis for a tick bite? Patient must meet ALL of the following criteria:

I.-scapularis.jpg

  1. I. scapularis tick

  2. Tick attached >36 hours

  3. Prophylaxis begins within 72 hours of tick removal

  4. Bite occurred in area with high rate of infection

  5. Doxycycline not contraindicated

    1. Patient > 8 years of age

    2. Not pregnant or lactating

Prophylaxis=Doxycycline 4mg/kg max 200mg one-time dose

*** If patient does not meet the criteria for antibiotic prophylaxis recommendation is that they be observed and only treated if signs of symptoms of Lyme Disease develop

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Anti-NMDA Encephalitis

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Today we are going to attempt to broaden your differential of altered mental status in the “young” patient.  While we attribute AMS or psychotic/bizarre behavior in many young patients to toxicologic causes or schizophrenia, there are other organic causes which are probably far more common than diagnosed. We are going to focus on one of these causes: Anti-NMDA Encephalitis

 

Symptoms

  • Many different presentations. Typically progresses in four stages.

  • Phase 1

o   May be prodrome of URI, flu-like syndrome, or headache.

  • Phase 2

o   Typically begins with a behavioral change

o   Cognition, memory, speech problems.

o   Odd behavior, however no prodrome: agitation, paranoia, psychosis.

o   Seizures

  • Phase 3

o   Automatisms: Twitching, lip smacking.

o   Catotonia, LOC

  • Phase 4

o   Autonomic dysfunction, hypoventiliation

 

Demographics

  • Mean age is 21 years old!

  • Mainly affects women (~80%).

  • 38% have a paraneoplastic syndrome, almost all of these are women (97%), typically associated with a teratoma (which contain tissue with NMDA receptors).

  • It appears to be the most common individual cause of encephalitis in those youngers than age 30, even more common than HSV encephalitis.

Cause

  • Thought to be an autoimmune issue caused by an antagonist again the NR1 subunit of the NMDA receptor.

  • Some of this autoimmune activity is thought to be invoked by tumors (teratoma, ovarian).

 

Workup

Rule out other causes ruled out (meningitis, toxicologic causes, herpes, etc).

Should get CSF.  Send for oligoclonnal bands.  You should also send CSF to test for the anti-NMDA antibody (in addition to HSV, etc).

Otherwise patient should get EEG, MRI, CSF (probably already performed) which show non-specific abnormalities.

Treatment

IVIG and Steroids (1G/day methylprednisone).  Consider plasmapheresis. Secondarily immunotherapy (rituximab) or cyclophosphamide.

 

Prognosis

Many patients take months to get better.  Phases of symptoms are generally reversed as patient improves. Those with masses do better as masses are removed. Additionally those with early treatment  do better.

Hopefully this helps to expand your differential in new onset AMS.  Remember to rule out other causes: meningitis, toxicologic, etc!

EM:RAP, David Carr

Aliem

California Encephalitis Project

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