In morning report on July 12 we discussed Lyme disease around a case where a patient presented with migratory polyarthralgias. See a summary of the key points below:

Overview:

Lyme disease is a tick borne illness, caused by the spirochete Borreliella. Borreliella burgdorferi is the primary cause of the disease in North America. Transmission is most likely to occur via tick bite between the months of May and October with a peak in June. 

Clinical manifestations:

Early localized disease (days to one month after tick bite)	Early disseminated disease (weeks to months after tick bite)	Late disease  (months to years after tick bite)
Erythema migrans (80%)	MSK (60% if untreated) – Migratory polyarthralgias  Neurologic disease (15% if untreated) – CN VII palsy – Lymphocytic meningitis – Peripheral neuropathy  Carditis (1%) – AV nodal block – mild cardiomyopathy  Skin – Multiple erythema migrans lesions Liver – hepatitis Lymphadenopathy – regional or generalized	MSK (60% if untreated) – mono or oligo articular arthritis; knee is most common Neurologic – peripheral neuropathy – encephalomyelitis

Approach to Diagnosis:

Erythema migrans (single or multiple lesions) – this diagnosis should be made on clinical grounds alone in patients who either live in or have recently travelled to an endemic area. Serologic testing is not needed or recommended prior to treatment.

Early disseminated or late disease – serologic testing is warranted (except in patients with multiple erythema migrans lesions, which are diagnostic in and of themselves). Serum antibodies for B. burgdoferi should be sent. 

note – serologic testing for B. burgdorferi is not particularly sensitive or specific for Lyme, so it should only be used as an adjunct to the clinical diagnosis and should not be used alone to rule Lyme in or out

Management:

Prophylaxis  (if [need all 3] 1.Tick is a deer tick 2.Tick attached >36h 3.Prophylaxis given within 72h tick removal)	Early localized disease (days to one month after tick bite)	Early disseminated disease (weeks to months after tick bite)	Late disease (months to years after tick bite)
Doxycycline 200mg PO x 1 dose	Doxycycline 100mg PO BID x10 days	Neurologic Disease (CN VII palsy, meningitis, peripheral neuropathy): Doxycycline 100mg PO BID x 14-21 days  Severe Neurologic Disease (encephalitis): Ceftriaxone 2g IV daily x14-28 days  Carditis (mild: asymptomatic with 1stdegree AV block and PR<300): Doxycycline 100mg PO BID x 14-21 days  Carditis (more severe: symptomatic, 2nd or 3rd degree AV block, PR>300): Ceftriaxone 2g IV x14-21 days	Arthritis: Doxycycline 100mg PO BID x28 days (if no improvement, THEN) – Ceftriaxone 2g IV daily x14-28 days

References:

1.        Treatment of Lyme disease – UpToDate. https://www.uptodate.com/contents/treatment-of-lyme-disease?search=lyme disease&source=search_result&selectedTitle=2~150&usage_type=default&display_rank=2. Accessed July 14, 2022.

2.        Bailey J. Lyme Disease guidelines. CMAJ. 2016;188(10):754-755. doi:10.1503/CMAJ.1150107

3.        Clinical manifestations of Lyme disease in adults – UpToDate. https://www.uptodate.com/contents/clinical-manifestations-of-lyme-disease-in-adults?search=lyme disease&source=search_result&selectedTitle=1~150&usage_type=default&display_rank=1. Accessed July 14, 2022.

4.        Deer Tick | National Geographic. https://www.nationalgeographic.com/animals/invertebrates/facts/deer-tick. Accessed July 14, 2022.