View source for Lyme disease

==Background==
[[File:Lyme Disease Risk Map.gif|thumb|National Lyme disease risk map with 4 categories of risk.]]
[[File:Ixodes scapularis.jpg|thumb|Ixodes tick]]
*Caused by spirochete ''Borrelia burgdorferi''
** Typically carried on Ixodes scapularis aka Deer tick
**The spirochete ''Borrelia mayonii'' has been a new strain implicated in cases in the midwest<ref>Pritt BS, Mead PS, Johnson DKH, et al.Identification of a novel pathogenic Borrelia species causing Lyme borreliosis with unusually high spirochaetaemia: a descriptive study. Lancet Infectious Disease. Published Online: 05 February 2016. </ref>
*Endemic to the northeastern US
*Peak time of infection is May to August
*Stages: Early localized infection, early disseminated, and late disseminated

==Clinical Features==
[[File:Erythema migrans - erythematous rash in Lyme disease - PHIL 9875.jpg|thumb|"Classic" bull's-eye rash (i.e. erythema migrans) found in 70%-80% of cases<ref name=CDC-Signs-Symptoms-April-2011>[http://www.cdc.gov/lyme/signs_symptoms/ Signs and Symptoms of Lyme Disease], CDC, page last reviewed: June 16, 2015.</ref>]]
''3 Distinct Stages - Not all patients suffer all stages, and stages may overlap with remissions between stages''

===Early Localized Infection (7-14 Days)===
*Erythema Chronicum Migrans: Occurs at site of tick bite, beginning with red macule that expands outward. Starts 3-30 days after bite and occurs in 70-80% of cases
*Erythema migrans rash more often without central clearing
*Fatigue, low grade [[fever]], migrating [[arthralgia]], lymphadenopathy, [[headache]], nausea/[[vomiting]], [[abdominal pain]]

===Early Disseminated Infection (Days to Weeks)===
*Skin- Multiple annular lesions that spare the palm and soles
*Nervous System-fluctuating [[meningoencephalitis]], [[headache]], [[nausea/vomiting]], [[cranial nerve palsies]] (ie 7th-can be bilateral) peripheral neuropathy, radiculopathy 
*Cardiovascular: [[AV blocks]], [[RBBB]], [[dysrhythmias]], LV dysfunction 
*Eye: [[Conjunctivitis]], keratitis, [[retinal detachment]], [[optic neuritis]]

===Late Disseminated Infection (Months to Years)===
*Arthritis: Monarticularule outligoarticular asymmetric arthritis (large joints-commonly knee) 
**Brief episodes separated with complete remission 
**Migratory pattern may occur 
*Nervous System: Subtle encephalopathy, fatigue, polyneuropathy

==Differential Diagnosis==
*[[Enterovirus]]
*[[Hepatitis]]
*[[Mononucleosis]]
*[[Connective tissue disease]]
*[[Erythema Multiforme]]
*CAD 
*[[Acute rheumatic fever]]
*Aseptic [[Meningitis]]
*[[HSV]] encephalitis 
*[[Bell's Palsy]] 
*[[Multiple Sclerosis]] 
*[[Guillain-Barre]]
*Cerebral vasculitis 

{{Differential Diagnosis Polyarthritis}}

{{Tick borne illnesses DDX}}

==Evaluation==

*ELISA if positive obtain confirmatory Western blot 
*PCR 
*Cultures, serologies 
*LP with lymphocytic pleocytosis, elevated protein, normal glucose, + spirochete antibody, paired serum/CSF serologic tests,PCR 
**Must be performed in patients with neuro findings (facial nerve palsy, meningoencephalitis, etc)
**CNS Lyme disease will be treated with ceftriaxone
*Arthrocentesis, serologic testing of fluid

==Management==
''No risk when duration of attachment <24 hrs''

===Prophylaxis===
*Adult: [[Doxycycline]] 200mg PO x1 
*Child >8: 4mg/kg up to 200mg PO x1 
*Give if all of the following are met: 
**Tick is adult/nymphal ''I. scapularis'' 
**Tick was attached >36 hours based on degree of engorgement or exposure time 
**Prophylaxis can be given within 72 hrs after time tick was removed 
**Local rate of infection in ticks >20% 
**Doxycycline is not contraindicated 
*Old vaccine has little to no efficacy after 1 year

===Early Localized Infection===

*Treat before serologic testing if endemic area if + erythema migrans rash 
**'''[[Doxycycline]]''' 100 mg PO BID x 10 days <ref name="IDSA guidelines">Clinical Practice Guidelines by the Infectious Diseases Society of America, American Academy of Neurology, and American College of Rheumatology
2020 Guidelines for the Prevention, Diagnosis, and Treatment of Lyme Disease. Lantos et al. Neurology Feb 2021, 96 (6) 262-273; DOI: 10.1212/WNL.0000000000011151</ref> 
***Acceptable for all pediatric patients when used for 21 days or less
***Also treats human granulocytic [[ehrlichiosis]]
**'''[[Amoxicillin]]''' 500 mg PO TID x 14 days <ref name="IDSA guidelines"/> 
***Preferred in pregnant, lactating
**[[Cefuroxime]] axetil 500 mg PO BID x 14 days <ref name="IDSA guidelines"/>
**[[Macrolides]]- not first line
*[[Jarisch-Herxheimer reaction|Jarisch-Herxheimer]] like reaction can occur in first 24 hrs of treatment (fevers, chills, myalgia, tachycardia)

===Early Disemminated===

*'''[[Doxycycline]]''' (see above dosing)

*'''[[Amoxicillin]]''' (See above dosing)

===Lyme Meningitis===

*'''[[Ceftriaxone]]''' 2g IVq12h x 14-28 days 
**[[Doxycycline]] 200-400mg/d divided into two doses q day x 10-28 days 
***Preferred for facial palsy or Lyme meningitis (lack of efficacy studies other medications)
**[[Penicillin G]], [[Cefotaxime]]

===Cardiac Disease===

*Mild (1st degree AV with PR <0.3 sec) 
**[[Doxycycline]]/[[Amoxicillin]] PO 
*Severe (HIgh-degree AV block) 
**[[Ceftriaxone]]/[[Pen G]] IV

===[[Arthritis]]===

*[[Doxycycline]], [[Amoxicillin]] PO, as effective as parenteral 
*[[Ceftriaxone]]/[[Pen G]] IV

==Disposition==
===Outpatient===
*Early Disease 
*Late Disease: If chronic neurologic/arthritic manifestations may be able to manage as outpatient
*Follow up with primary care, rheum, ID <br>

===Admission===
*Lyme carditis-cardiac monitoring 
*Prominent neurologic symptoms for IV antibiotics and further care

==See Also==
*[[Tick Borne Illnesses]]
*[[Bell's palsy]]
*[https://www.nejm.org/doi/10.1056/NEJM200107123450207?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed Allen C. Steere, "Lyme disease" N Engl J Med 2001; 345:115-125. Accessed 13 Jan 2021.]
*[[In-training exam review]]

==External Links==
*[https://www.cdc.gov/lyme/index.html CDC: Lyme Disease]

==References==
<references/>

[[Category:ID]]