Lyme Disease

Review here and NEJM reviews here and here. IDSA 2006 guidelines on tick borne illness here.

Transmitted by ticks of the Ixodes family, usually nymphs (see photos), this spirochete infection causes the following recognized syndromes:

1. Early localized infection: characteristic rash (erythema chronica migrans) with cleared centre, of at least 5cm diameter, in context of possible fever, chills, headache, malaise, myalgias.
   
2. Early disseminated infection: few days to weeks post infection. Additional ECM lesions in presence of musculoskeletal symptoms (60% - i.e. migratory arthritis, muscle and joint pain), neurological (15% -- i.e. facial nerve palsy, menigoencephalitis, radiculopathies) or cardiac (10% -- i.e. AV block)
3. Late disseminated infection: up to 60% untreated. Arthritis of knees and hips, occasionally a slowly progressive encephalopathy or polyradiculopathy.

Recent article on the emergence of this disease in Canada. This article has probably caused more phone calls to the ID service for 'Lyme' in the past few months than in the past few years. The article demonstrates the expansion of the territory of the Ixodes tick and the concern is that where the tick goes, the pathogen will eventually follow.

Treatment for early disease is oral doxycycline (or amoxicillin in patients whom doxycycline is contraindicated) for 14-21 days. EDIT: 10 days is sufficient

Remember: to get Lyme disease you need to be bitten by the right tick (see below), at the right time of year, in the right place in the world. The majority of consults seen outside endemic areas (or travel to) involve the wrong tick and the wrong place. In these cases Lyme serology will *not* be helpful due to the low specificity.

NB: NEJM review of 'chronic lyme disease' that is worth a read....


I found this site useful as well...

Addendum -- Death from chronic lyme treatment...