01Approach to the Critical Patient/attcp58

Alarm features and escalation triggers

›Neurologic emergencies

›Rapidly progressive encephalomyelitis

›Spastic paraparesis or ataxia

›Bladder dysfunction

›Cranial neuropathies with progression

›Signs of raised intracranial pressure

›Papilledema

›Depressed consciousness

›New focal neurologic deficits

›Motor weakness

›Sensory loss in dermatomal distribution

›Cardiac emergencies

›High-degree AV block

›PR interval >300 ms

›Complete heart block

›Syncope or presyncope

›Hemodynamic instability from Lyme carditis

›SBP <90 mmHg

›Bradycardia with poor perfusion

›If complete heart block, temporary pacing preparation

›Cardiology consult emergent

›IV ceftriaxone initiation without delay

›Joint emergencies

›Synovial WBC >100,000/µL suggesting septic arthritis

›Gram stain and culture priority

›Orthopedic or rheumatology consult

›Large tense effusion with hemodynamic compromise

02History/hx92

Symptom timeline and joint presentation

›Core joint symptoms

›Intermittent monoarticular or oligoarticular joint swelling

›Knee most commonly affected

›Episodes lasting weeks to months

›Pain-free intervals between flares

›Distinguishes from rheumatoid arthritis

›Weeks to months between episodes

›Oligoarticular pattern

›Large joint predilection

›Ankle, shoulder, elbow involvement possible

›Onset and timing context

›Onset typically >6 months after tick bite

›Many patients lack recall of tick exposure

›Prior erythema migrans in only 50–80% of cases

›No recollection of early Lyme symptoms

›Silent dissemination possible

›Untreated early disease in ~60% progress to disseminated stage

Neurologic symptoms

›Cognitive and central symptoms

›Memory impairment

›Difficulty with short-term recall

›Concentration difficulties

›Lyme encephalopathy features

›Fatigue

›Sleep disturbance

›Depression as associated finding

›Peripheral neurologic symptoms

›Paresthesias

›Stocking-glove distribution

›Radicular pain distribution

›Cranial nerve involvement

›Facial weakness (CN VII)

›Diplopia (CN VI)

›Rare severe neurologic features

›Progressive encephalomyelitis

›Spastic paraparesis

›Ataxia

›Bladder dysfunction

Skin and other organ symptoms

›Acrodermatitis chronica atrophicans (European Borrelia afzelii)

›Slowly progressive bluish-red skin discoloration

›Extensor surfaces of extremities

›Years of progression without treatment

›Tissue-paper thin skin atrophy in late stages

›Prominent subcutaneous veins visible

›Fibrous nodules at joint prominences

›Cardiac symptoms

›Palpitations

›Paroxysmal or persistent

›May be presenting feature of Lyme carditis

›Presyncope or syncope

›Exertional or postural trigger

›High-degree AV block correlation

›Exercise intolerance

›Fatigue on exertion

›Dyspnea on exertion

Exposure history and risk factors

›Tick exposure history

›Outdoor activities in endemic areas

›Northeast US (CT, MA, NY, NJ, PA, MD, VA, DE, RI, VT, NH, ME)

›Upper Midwest US (MN, WI)

›Northern Europe

›Hiking, gardening, hunting, camping

›Peak transmission May through September

›Nymphal tick activity highest risk period

›Occupational outdoor exposure

›Forestry, landscaping, military training

›Lawn maintenance in endemic suburban areas

›Prior Lyme history and treatment

›Previous episodes of Lyme disease

›Prior antibiotic courses

›Incomplete or no prior treatment

›Prior serology results

›Persistent seropositivity complicates interpretation

›IgG remains positive for years after infection

›HLA-DR4 or HLA-DR2 status

›Associated with post-antibiotic Lyme arthritis risk

›Immune-mediated mechanism

Past medical history and medications

›Relevant comorbidities

›Immunosuppression

›May cause seronegative late Lyme in rare cases

›Transplant, HIV, malignancy

›Pre-existing joint disease

›Osteoarthritis altering presentation

›Crystal arthropathy coexistence possible in adults

›Autoimmune conditions

›Differential diagnosis relevance

›Post-antibiotic arthritis risk

›Current medications

›NSAIDs use

›Symptom masking assessment

›Partial treatment effect

›Immunosuppressants

›Impact on serology

›Impact on clinical presentation

03Physical Exam/exam77

Musculoskeletal examination

›Joint findings

›Knee effusion

›Large warm joint effusion most common

›Often mildly tender or painless

›Baker's cyst

›Posterior knee fullness

›Bulge sign positive

›Quadriceps atrophy

›Chronic or refractory cases

›Disuse pattern

›Range of motion assessment

›Flexion limitation from effusion

›Quantify range limitation

›Comparison to contralateral side

›Other large joint examination

›Ankle, shoulder, elbow, wrist

›Oligoarticular distribution pattern

Neurologic examination

›Cranial nerve assessment

›CN VII facial weakness

›Forehead involvement differentiates from central

›Asymmetry of smile

›Extraocular movements

›CN VI palsy

›Nystagmus

›CN VIII hearing assessment

›Sensorineural loss possible

04Differential Diagnosis/ddx62

Life-threatening diagnoses

›Septic arthritis

›ICD-10 M00.9

›SNOMED CT septic arthritis disorder

›Synovial WBC typically >100,000/µL

›Mean ~128,000 vs ~46,000–60,000 in Lyme arthritis

›Positive Gram stain or culture

›Fever more prominent

›Rapid clinical deterioration

›Immediate surgical consultation

›Lyme carditis with high-degree AV block

›ICD-10 I01.2 classification context

›Potentially life-threatening without pacing

›Syncope and hemodynamic compromise

›Differentiated by serologic context

›Concurrent tick exposure history

›Endemic area residence

Inflammatory and rheumatologic mimics

›Rheumatoid arthritis

›ICD-10 M06.9

›Symmetric polyarthritis pattern

›RF and anti-CCP positive

›Common chronic Lyme misdiagnosis source

›Seronegative Lyme unlikely in late stage

›Anti-CCP differentiates

›Reactive arthritis

›Post-infectious trigger

›Urethritis and conjunctivitis triad

05Laboratory Tests/lt69

Serologic diagnosis

›Two-tiered serology algorithm

›First tier ELISA or EIA screening

›High sensitivity but lower specificity alone

›Positive or equivocal result requires second tier

›Second tier IgG Western blot

›Five or more of 10 bands positive required

›p41, p18, p23, p28, p30, p39, p45, p58, p66, p93 bands

›IgG invariably positive in late Lyme disease

›IgM-only positivity without IgG after >30 days unreliable

›Seronegative late Lyme disease essentially excluded in immunocompetent

›Modified two-tier testing (MTTT)

›Two EIA assays without Western blot

›Comparable sensitivity to standard two-tier

›Faster laboratory turnaround

›FDA-cleared algorithm

›Centers for Disease Control endorsement

›Equivalent performance for late disease

Synovial fluid analysis

›Arthrocentesis indications and interpretation

›Joint WBC count

›Lyme arthritis typically 25,000–60,000/µL

›Neutrophil predominant

›Gram stain and culture

›Mandatory to exclude septic arthritis

›Borrelia will not grow on standard culture

›Crystal analysis

›Monosodium urate for gout

06Diagnostic Tests/dt88

Scoring Systems

›Diagnostic probability tools

›Two-tiered serology interpretation framework

›Stage 3 requires positive IgG Western blot with clinical syndrome

›Clinical probability must guide serology interpretation

›Pre-test probability assessment

›Endemic area exposure

›Compatible clinical syndrome

›Appropriate timing after tick exposure

›Limitations of scoring

›No validated point-of-care risk score for late Lyme

›Clinical judgment with serology guides diagnosis

›IDSA diagnostic criteria

›Lyme arthritis diagnosis

›Positive two-tier serology

›Monoarticular or oligoarticular arthritis

›Appropriate exposure history

›Late neuroborreliosis criteria

›Positive two-tier serology

›Objective neurologic findings

›CSF intrathecal antibody index >1 (supportive)

›Evidence level for diagnostic criteria

›IDSA Class I recommendation for two-tier serology

›ACEP Level B recommendation for serologic testing in suspected Lyme

MRI

›MRI brain and spine indications

›Late neuroborreliosis evaluation

›White matter T2/FLAIR hyperintensities

›Periventricular and subcortical distribution

›Leptomeningeal enhancement with contrast

›Active meningitis component

›Cranial nerve enhancement possible

›Spinal cord involvement

›T2 signal change in encephalomyelitis

›Distinguishes from MS plaques

›MRI joint evaluation

›Synovial thickening

›Pannus formation in chronic cases

›Gadolinium enhancement in active synovitis

›Effusion characterization

›Volume quantification

›Associated Baker's cyst

›Cartilage and bone assessment

›Erosive changes in refractory cases

›Differentiates from osteoarthritis

›MRI limitations

›Not required for straightforward Lyme arthritis

›Positive serology with typical clinical syndrome sufficient

›Reserve for complex or atypical presentations

CT

›CT indications in Lyme disease context

›Neurologic complications

›CT head when focal deficits or altered consciousness

›Excludes hemorrhage before lumbar puncture

›Cardiac complications

›CT chest if myocarditis with heart failure suspected

›Pericardial effusion assessment

›CT limitations for Lyme diagnosis

›Not useful for joint or soft tissue Lyme evaluation

›MRI preferred for CNS and joint assessment

›CT technical considerations

›Contrast use

›Renal function assessment

›Allergy history review

›Radiation exposure consideration

›Pediatric dose optimization

›Pregnancy implications

Ultrasound

›Joint ultrasound applications

›Effusion detection and characterization

›Anechoic fluid in joint space

›Power Doppler for active synovitis

›Baker's cyst confirmation

›Posterior knee communication with joint

›Rupture assessment

›Arthrocentesis guidance

›Safe needle trajectory

›Maximizes fluid yield

›Nerve ultrasound

›Peripheral neuropathy assessment

›Nerve cross-sectional area measurement

›Nerve echotexture change

›Complement to nerve conduction studies

›Structural compressive lesion exclusion

›Operator-dependent limitation

›Cardiac ultrasound

›Myocarditis or pericarditis assessment

›Global LV function

›Pericardial effusion detection

›ACEP Level B recommendation for POCUS in undifferentiated cardiac dysfunction

›Rapid bedside tool

›Guides further testing

07Disposition/dispo59

Admission indications

›Mandatory admission criteria

›High-degree AV block

›Second-degree Mobitz II or third-degree

›PR interval >300 ms

›Hemodynamic instability from carditis

›Vasopressor or pacing requirement

›ICU level care

›Rapidly progressive encephalomyelitis

›New spastic paraparesis or ataxia

›Bladder dysfunction

›Septic arthritis cannot be excluded

›Synovial WBC >100,000/µL

›Systemic toxicity features

›IV therapy admission indications

›Late neuroborreliosis

›IV ceftriaxone requirement

›14 to 28 day course

›Failed oral therapy for Lyme arthritis

›No response to two 28-day oral courses

›IV ceftriaxone 2 to 4 weeks

›Lyme carditis with block

›Monitoring until block resolves

›Telemetry requirement

Discharge criteria and outpatient management

›Safe discharge criteria for Lyme arthritis

›Hemodynamically stable

›Normal vital signs

08Treatment/t112

First-line antibiotic therapy for Lyme arthritis

›Oral doxycycline (preferred first-line)

›100 mg PO twice daily

›Duration 28 days

›Take with food and water

›Avoid within 2 hours of dairy or antacids

›Reduces absorption by chelation

›Optimal fasting if tolerated

›IDSA Class I recommendation

›Preferred over amoxicillin in adults

›Superior CNS penetration for subclinical neurologic involvement

›Oral amoxicillin (alternative)

›500 mg PO three times daily

›Duration 28 days

›Preferred in pregnancy or doxycycline intolerance

›Class I recommendation per IDSA

›Equivalent efficacy for Lyme arthritis

›No CNS penetration limitation for arthritis indication

›Oral cefuroxime axetil (alternative)

›500 mg PO twice daily

›Duration 28 days

›Beta-lactam option

›Class I recommendation

›Use when doxycycline and amoxicillin contraindicated

›Avoid in severe penicillin allergy with cross-reactivity concern

IV antibiotic therapy

›Ceftriaxone IV (late neuroborreliosis and failed oral therapy)

›2 g IV once daily

›Duration 14 to 28 days for neuroborreliosis

›Duration 2 to 4 weeks for failed oral Lyme arthritis

›Renal and hepatic function monitoring

›Hepatobiliary sludge risk with prolonged use

›Renal dosing generally not required

›IDSA Class I recommendation for late neuroborreliosis

›Superior to oral therapy for CNS penetration

›Consider step-down to oral doxycycline after initial IV course

›Cefotaxime IV (neuroborreliosis alternative)

›2 g IV every 8 hours

›Duration 14 to 28 days

›Equivalent to ceftriaxone for neuroborreliosis

›Use when ceftriaxone not available or tolerated

›Similar spectrum and CNS penetration

›More frequent dosing required

›IV penicillin G (neuroborreliosis alternative)

›18 to 24 million units per day IV

›Divided every 4 hours or continuous infusion

›Duration 14 to 21 days

›Allergy review required

›Penicillin allergy cross-reactivity assessment

›Ceftriaxone preferred in most settings

Lyme carditis treatment

›Antibiotic selection by block severity

›Mild cardiac involvement (PR <300 ms, first-degree block)

›Oral doxycycline 100 mg twice daily for 14 to 21 days

›Outpatient monitoring with ECG follow-up

›Moderate to severe block (second-degree or third-degree)

›IV ceftriaxone 2 g daily

›Inpatient monitoring until block resolves

›Resolution expected within days to weeks with treatment

›Most cases resolve without permanent pacing

›Temporary pacing if hemodynamically compromised

›Cardiac monitoring during treatment

›Serial ECG

›PR interval trending

›Block degree monitoring

›Telemetry until PR interval <300 ms or block resolving

›Discharge when stable rhythm

›Outpatient ECG at 1 to 2 weeks

Post-antibiotic Lyme arthritis management

›Anti-inflammatory therapy

›NSAIDs

›Ibuprofen 400–600 mg PO three times daily with food

›Naproxen 500 mg PO twice daily

›Intra-articular corticosteroids

›Triamcinolone acetonide 40 mg intra-articular injection

›Only after antibiotic course completion

›Oral corticosteroids for refractory inflammation

›Prednisone 20–40 mg/day with taper

›Short course after documented antibiotic failure

›Disease-modifying antirheumatic drugs

›Hydroxychloroquine

›200–400 mg PO daily

›Ophthalmologic monitoring

›Methotrexate

›7.5–25 mg PO or SC weekly

›Folic acid 1 mg daily supplementation

›TNF inhibitors for refractory cases

›Rheumatology oversight required

›After failure of conventional DMARDs

›Arthroscopic synovectomy

›Refractory cases unresponsive to antibiotics and DMARDs

›Orthopedic referral

›Typically after 6 months of failed treatment

›Synovial PCR to confirm no active infection before procedure

›Active infection should receive further antibiotic course

›PCR negative supports surgical candidacy

Antibiotic limitations and contraindications

›Agents not recommended

›Macrolides (azithromycin) as monotherapy

›Higher treatment failure rates

›Second-line only with superior options available

›Prolonged antibiotic courses

›No benefit beyond 8 weeks total including IV

›Risk of Clostridium difficile infection

›IV antibiotics for post-Lyme syndrome

›No objective inflammation markers

›Harm without benefit demonstrated in RCTs

›Doxycycline contraindications

›Pregnancy avoidance

›Amoxicillin preferred

›Fetal bone and tooth risk

›Children under 8 years traditional contraindication

›Recent IDSA guidance relaxing restriction for short courses

›Risk-benefit assessment per case

›Severe esophageal disease or dysphagia

›Pill esophagitis risk

›Amoxicillin or cefuroxime alternative

09Special Populations/sp77

Pregnancy

›Pregnancy-specific considerations

›Antibiotic selection modification

›Doxycycline contraindicated in all trimesters

›Amoxicillin 500 mg PO three times daily for 28 days preferred

›Cefuroxime axetil as alternative

›500 mg PO twice daily for 28 days

›Safe in pregnancy

›IV ceftriaxone for severe or CNS disease

›2 g IV daily for 14 to 28 days

›Generally considered safe in pregnancy

›Fetal and perinatal concerns

›No proven vertical transmission in treated mothers

›Case reports of congenital Lyme unconfirmed

›Treat promptly to minimize any theoretical risk

›Obstetric consultation for severe disease

›Carditis or neuroborreliosis in pregnancy

›Fetal monitoring when viable gestation

›Monitoring during treatment

›Amoxicillin generally safe in first trimester

›Monitor for allergic reactions

Geriatric

›Age-related presentation differences

›Atypical symptom profile

›Delirium as presenting feature of neuroborreliosis

›Functional decline as primary complaint

›Bimodal incidence peak in 50–64 year age group

›High exposure risk from outdoor recreational activities

›Less vigorous tick removal behavior

›Frailty implications

›Lower functional reserve for infection

›Polypharmacy drug interaction risk

›Medication adjustments in older adults

›Doxycycline tolerability

›GI upset more common

›Take with food and upright posture

›Renal function monitoring

›Ceftriaxone generally safe but hepatobiliary monitoring

›Amoxicillin renal dose adjustment when GFR <30 mL/min

›QT prolongation risk assessment

›Macrolides and fluoroquinolones higher risk in elderly

›Preferred agents do not prolong QT

›Differential diagnosis considerations in elderly

›Rheumatoid arthritis overlap

›Seronegative RA vs Lyme arthritis

›Anti-CCP testing

›Degenerative joint disease masking Lyme arthritis

›Effusion in osteoarthritic knee may be Lyme

›Serology essential in endemic area presentations

Pediatrics

›Pediatric presentation features

›Bimodal age peak at 5–14 years

›Highest incidence age group for Lyme disease overall

›High outdoor play exposure in endemic areas

›Fever more common than in adults

›Temperature >38 C during flare

›Systemic symptoms more prominent

›Monoarticular knee arthritis classic presentation

›Often dramatic warm swollen knee

›May appear more systemically ill than adult

›Antibiotic dosing in children

›Doxycycline in children ≥8 years

›4.4 mg/kg/day divided twice daily (maximum 100 mg per dose)

›Duration 28 days

›Amoxicillin in children <8 years or doxycycline intolerance

›50 mg/kg/day divided three times daily (maximum 500 mg per dose)

›Duration 28 days

›Cefuroxime axetil alternative

›30 mg/kg/day divided twice daily (maximum 500 mg per dose)

›Duration 28 days

›IV ceftriaxone for neuroborreliosis or cardiac involvement

›50–75 mg/kg/day (maximum 2 g/day)

›Duration 14 to 28 days

›Juvenile idiopathic arthritis differential

›Seronegative Lyme essential to distinguish from JIA

›Two-tier serology negative in JIA

›ANA and RF testing for JIA

›Endemic area context critical for diagnosis

›JIA more common outside endemic areas

›Pediatric rheumatology consultation for diagnostic uncertainty

10Background/b96

Epidemiology

›Disease burden and distribution

›Most reported vector-borne illness in the United States

›Approximately 476,000 cases diagnosed annually in the US

›95% of US cases from 14 endemic states

›Global distribution

›Europe: Borrelia afzelii and B. garinii predominant

›North America: Borrelia burgdorferi sensu stricto

›Bimodal age distribution

›Children 5–14 years

›Adults 50–64 years

›Late disseminated disease frequency

›Approximately 60% of untreated patients develop disseminated disease

›Arthritis most common manifestation in North America

›ACA predominant in European late disease

›Lyme arthritis affects 60% of untreated patients within months to years

›Knee involvement in >90% of arthritis cases

›Oligoarticular pattern typical

›Late neuroborreliosis less common in North America

›Encephalomyelitis rare

›More common with European Borrelia species

›Seasonal and geographic patterns

›Peak transmission May through September

›Nymphal stage Ixodes scapularis highest risk

›Nymphs are small and easily missed

›Tick attachment duration 36 to 48 hours required for transmission

›Prompt removal reduces risk

›Engorged ticks with >36 hours attachment highest risk

Pathophysiology

›Borrelia infection mechanisms

›Spirochete dissemination from skin

›Hematogenous and lymphatic spread

›Joint tropism via OspC and other surface proteins

›Joint invasion mechanism

›Borrelia binds to synovial cells and cartilage matrix

›Persists in extracellular matrix

›Complement evasion

›OspE binds factor H

›Serum resistance enables dissemination

›Lyme arthritis pathophysiology

›Inflammatory synovitis driven by innate and adaptive immunity

›Neutrophil-predominant acute phase

›T-cell infiltration in chronic synovitis

›Post-antibiotic (refractory) Lyme arthritis

›Autoimmune mechanism after organism clearance

›Molecular mimicry hypothesis

›HLA-DR4 associated T-cell reactivity to Borrelia antigens

›Synovial cytokine profile

›IL-6, IL-17, IFN-gamma elevated

›TNF-alpha in active synovitis

›Neuroborreliosis pathophysiology

›CNS invasion via hematogenous route

›Blood-brain barrier disruption

›Perivascular inflammation

›Intrathecal antibody production

›B-cell infiltration of CNS

›CSF pleocytosis from immune activation

›White matter damage

›Vasculitis mechanism

›Demyelination in severe cases

›Cardiac pathophysiology

›AV nodal conduction tissue inflammation

›Spirochete invasion of conduction system

›Lymphocytic infiltration

›Complete heart block self-limited in most cases

›Resolution with antibiotic therapy

›Permanent pacing rarely required

Therapeutic Considerations

›Antibiotic selection rationale

›Doxycycline preferred for intracellular penetration

›Superior CNS penetration vs beta-lactams

›Active against co-infecting Anaplasma

›Beta-lactam options for arthritis

›Amoxicillin and cefuroxime equivalent efficacy

›No CNS penetration advantage for isolated arthritis

›IV ceftriaxone reserved for CNS disease and oral failure

›Unnecessary for straightforward Lyme arthritis

›Risk of hepatobiliary complications with prolonged use

›Duration of therapy evidence

›28 days for Lyme arthritis based on clinical trials

›Shorter courses associated with higher recurrence

›No benefit demonstrated beyond 28 days oral

›Post-antibiotic Lyme arthritis not responsive to additional antibiotics

›RCTs show no benefit from prolonged IV antibiotics

›IDSA Class I recommendation against prolonged antibiotics

›Two-tiered approach for oral failure

›Second oral course or transition to IV ceftriaxone

›Rheumatologic management after two adequate antibiotic courses

›Immune modulation considerations

›NSAIDs as first anti-inflammatory for post-antibiotic arthritis

›Reduces synovial inflammation

›Low toxicity profile for limited duration

›Corticosteroid use caution

›May suppress immune response beneficial to spirochete clearance

›Reserve for documented post-antibiotic phase

›DMARD evidence base

›Small case series and expert consensus

›Hydroxychloroquine and methotrexate most studied

›TNF inhibitors effective in treatment-refractory cases

11Patient Discharge Instructions/pdi51

copy discharge instructions

›Lyme disease late stage home care

›Antibiotics exactly as prescribed for the full 28 days

›Do not stop early even if feeling better

›Doxycycline: take with a full glass of water and food

›Doxycycline and sun sensitivity

›Avoid prolonged sun exposure during treatment

›Use sunscreen SPF 30 or higher outdoors

›Amoxicillin: take with or without food

›Watch for allergic reactions

›Rash, hives, or swelling require medical attention

›Rest the affected joint if swollen

›Gentle range of motion as tolerated

›Avoid high-impact activity until swelling resolves

›Warning signs to return to the ER immediately

›New heart symptoms

›Fainting or near-fainting

›Irregular or very slow heartbeat

›Chest pain or shortness of breath

›Worsening neurologic symptoms

›Sudden weakness or numbness in limbs

›Severe headache with neck stiffness

›Facial drooping or double vision

›Confusion or difficulty thinking clearly

›Joint signs of serious infection

›Dramatically increasing swelling, redness, or warmth

›Fever above 38.5 C with joint pain

›Inability to bear weight

12References/r27

Guidelines and key sources

›Primary clinical guidelines

›IDSA Clinical Practice Guidelines for Lyme Disease 2006 and 2020 updates

›Wormser GP et al. Clinical Infectious Diseases 2006;43:1089–1134

›Lantos PM et al. 2021 IDSA Clinical Practice Guidelines

›CDC two-tiered testing framework

›Modified two-tier testing algorithm

›Endorsed for all stages including late disease

›ACEP Clinical Policy: Evaluation and Management of Lyme Disease

›Level B recommendation for two-tier serology

›Level B recommendation for doxycycline oral therapy

›Key clinical evidence

›Logigian EL et al. Late neurologic Lyme disease. New England Journal of Medicine 1990

›Late encephalopathy responds to IV ceftriaxone

›Foundational late neuroborreliosis evidence

›Klempner MS et al. Two controlled trials of antibiotic treatment. NEJM 2001

›No benefit from prolonged antibiotics in post-Lyme syndrome

›IV ceftriaxone followed by doxycycline vs placebo

›Steere AC et al. Lyme arthritis: overview. Arthritis and Rheumatism landmark series

›Established clinical features of Lyme arthritis

›Outcome data for treated and untreated cohorts

›Diagnostic test references

›Eldin C et al. Modified two-tier testing performance

›Comparable sensitivity to standard algorithm

›Journal of Clinical Microbiology evidence base

›PCR sensitivity data for synovial fluid

›71–100% sensitivity pre-treatment

›Positive post-treatment does not indicate active infection

Evidence & Review