Podcast #169: Lyme Disease

bd9fdb03-4845-4c2d-b1fc-f4bcd1253d7cRun Time:  7 minutes

Author: Greg Burcham M.D.

Educational Pearls:

  • Case presentation: A 48 year-old male cyclist travels to new england for a race. Afterwards he is sore, tired and fatigued, but 1 week later back in Colorado he is still sore, tired, and fatigued, and he also noticed a rash that started after a few days. The patient presents to the ED after a syncope with HR in the low 40s.
  • This patient has Lyme Disease. Hallmarked by the rash that he has, known as erythema migrans – a migrating red rash.
  • Symptoms usually present 1-2 weeks after a tick bite, and generally start as nonspecific – fever, myalgias, headache, arthralgias, malaise. 80% of patients present with the rash that starts as a small red lesion that enlarges with a bright red border.
  • A smaller percentage of patient get early disseminated disease. The most concerning complications are cardiac – Atrioventricular Block, bradycardia, and syncope – or a meningitis presentation.
  • Late disseminated findings include chronic joint and muscle arthralgias, seizures, paresthesias, memory and cognitive changes. Amy Tan – author of The Joy Luck Club – has chronic lyme and she loses memory if she is off her antibiotics for any period of time.
  • Lyme Disease is increasing by more than 10% per year for several years due to the destruction of habitat of predators, leading to mice population explosion, and global warming.
  • Each stage of the tick life cycle require a blood meal – larva to nymph to adult. Normally larva find it hard to get a blood meal in the fall after they hatch in the late summer. The larva go dormant until spring when they are able to find a blood meal and eventually become adults so the life cycle can start over on an annual basis.
  • As the climate has warmed a higher percentage of larvae are feeding earlier in the year, with a greater frequency in the New England area.
  • The bacteria that causes Lyme Disease needs time to replicate in the host, but due to asynchronous feeding between the mice and ticks there is a higher concentration of the bacteria in both the mice and the ticks.

Link to Podcast: http://medicalminute.madewithopinion.com/lyme-disease/

References: http://rstb.royalsocietypublishing.org/content/370/1665/20140051

https://www.cdc.gov/lyme/

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