summary Lyme Disease is a systemic infection caused by tick-born B. burgdorferi which usually presents with flu-like symptoms, a characteristic rash, and occasionally acute joint effusions. Diagnosis is confirmed by a history of travel to a tick-heavy regions, presence of erythema migrans rash, and a positive lyme titers on an ELISA test. Treatment is usually oral doxycycline for acute or mild disease. Epidemiology Incidence most common tick-borne illness in the US 19,931 cases in 2006 most cases occur in June, July, and August Demographics bimodal age distribution children 5-9 (8.6 cases/100,000) adults 55-59 (7.8 cases/100,00) geographic locations northeast, midwest, western US (areas with heavy deer population) Maryland to Maine (Ixodes scapularis) Great Lakes region (Ixodes scapularis) Pacific Northwest (Ixodes pacificus) Etiology Pathophysiology mechanism of transmission zoonotic - transmitted from nonhuman animals to humans mice, squirrels, shrews, and other small mammals are carriers of B burgdorferi Ixodes tick feeds on these small animals and spirochete is carried in its gut humans become infected when bacteria is injected into the skin as ticks attach to feed transmission takes 48-72 hours pathophysiology caused by B burgdorferi tick saliva with spirochete disrupt local immune mechanisms create a protective environment and the bacteria replicate spirochetes multiply and expand within the dermis, causing erythema migrans rash caused by the host inflammatory response the spirochete then undergoes hematogenous dissemination to multiple sites skin central nervous system joints induces an inflammatory response synovial hypertrophy vascular proliferation infiltration of mononuclear cells immune complexes accumulate in synovial fluid pathobiology B burgdorferi induces chondrocytes to produce matrix metalloproteinases causes degradation of extracellular matrix proteins, collagen, and proteoglycans may contribute to cartilage damage Classification Stage 1 (rash) - early localized 1 to 30 days after bite erythema migrans (bull's-eye rash) is hallmark rash may be found on head, neck, arms, legs, back, abdomen, axilla, groin, and chest flu-like symptoms fatigue headache malaise Stage 2 (neurologic and cardiac) - early disseminated weeks to months after bite progresses to stage 2 in 15-20% of untreated patients neurologic symptoms CN VI palsy CN VII palsy lymphocytic meningitis migratory polyarthritis or monoarthritis, tendonitis, bursitis Lyme carditis relatively rare may have a cardiac conduction abnormality symptoms syncope fatigue dizziness shortness of breath palpitation prognosis good with complete resolution following treatment Stage 3 (arthritis) - late months to years after bite occurs in 60% of untreated patients arthritis (usually the knee) swelling disproportionate to tenderness intermittent arthritis chronic monoarthritis acrodermatitis chronica atrophicans Presentation History tick bite in May through November Symptoms fever, headache, myalgia, arthralgia, fatigue neurologic symptoms headache, neck stiffness, encephalitis facial CN VII palsy bilateral in 50% (unlike Bell's palsy) polyradiculoneuropathy numbness, paresthesia, weakness, cramps carditis (complete heart block) acute joint pain acute or chronic arthritis Physical exam erythema migrans ("bullseye rash") in 60-80% of patients expanding rash >5cm diameter 1 to 3 weeks after tick bite itching or burning fades after 1 month at axillary or gluteal folds, hairline, near elastic bands (bra strap or underwear) acute, self limiting joint effusions knee and shoulder recurrent acrodermatitis chronica atrophicans "cigarette paper" skin dorsum of hands, feet, knees, elbows in older patients Studies Serum labs WBC normal or elevated ESR, CRP elevated ELISA (sensitive, not specific) 2 steps if ELISA positive, proceed to Western blot (specific) seroconversion takes weeks to become positive prior Lyme disease might have persistently positive results vaccination gives positive ELISA, negative Western blot CSF (patients with polyradiculitis and CN VII neuropathy) increased protein lymphocytic pleocytosis Joint aspiration / Synovial fluid 10,000-25,000 WBC/mm3 lower than baterial septic arthritis PMN predominance Skin biopsy culture Culture on Barbour-Stoenner-Kelly medium use skin edge punch biopsy from erythema migrans lesion PCR Differential Bacterial septic arthritis features that differentiate Lyme's diseae from bacterial septic arthritis include ability to bear weight normal serum WBC lower synovial fluid WBC count Treatment Non-operative oral antibiotics for mild disease indications in endemic regions, if erythema migrans is present, start antibiotics without blood tests medications adults doxycycline (not in children <8 years) x 10 days amoxicillin cefuroxime children (<8-years-old) amoxicillin cefuroxime IV antibiotics indications arthritis and neurologic involvement patients whose symptoms are unchanged after oral therapy medications IV ceftriaxone or cefotaxime IV penicillin G Operative synovectomy indications chronic arthritis not responding to IV antibiotics Complications Persistent joint pain may have a slightly increased incidence of persistent joint swelling despite therapy Chronic Lyme disease disabling musculoskeletal pain neurocognitive symptoms fatigue Chronic arthritis rare
QUESTIONS 1 of 7 1 2 3 4 5 6 7 Previous Next Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK (OBQ12.211) A 13-year-old boy presents to the emergency department in Rhode Island with knee pain for three days duration. It was atraumatic in onset. He has been afebrile. Upon physical examination, he is noted to have a tense, swollen knee and the skin lesion seen in Figure A. An oral course of antibiotics is selected as definitive management. What antibiotic would be most appropriate for this patient, and what is its primary mechanism of action? QID: 4571 FIGURES: A Type & Select Correct Answer 1 Doxycycline, Inhibits the 50s ribosomal subunit 27% (1172/4406) 2 Doxycycline, Inhibits the 30s ribosomal subunit 61% (2690/4406) 3 Cephalexin, Blocks cell wall synthesis 8% (369/4406) 4 Cephalexin, Folic acid inhibitor 1% (30/4406) 5 Rifampin, RNA synthesis inhibitor 2% (103/4406) L 4 Question Complexity C Question Importance Select Answer to see Preferred Response SUBMIT RESPONSE 2 Review Tested Concept Review Full Topic Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK Sorry, this question is for PEAK Premium Subscribers only Upgrade to PEAK
All Videos (0) Podcasts (1) Pediatrics | Lyme Disease Pediatrics - Lyme Disease Listen Now 16:17 min 10/21/2019 180 plays 4.7 (3)