Ticke-Borne Illnesses

Creepy, Crawly KillersTick-Borne Illnesses

Tick Identification

http://www.tickencounter.org/tick_identification2

Lyme DiseaseTransmitted by Ixodes scapularis deer tick

Borrelia burgdorferiMost common vector-borne zoonotic infection in the United States

-24,000 confirmed cases in 2011-Northeast and upper Midwest

7Seasonal VariationMost cases occur in the warmer monthsOutdoor activity is highest Nymph activity is at its peakStages: PrimarySymptoms: 7-10 days after biteErythema migrans: 80% of patientsBelt line, axillary, inguinal, or popliteal25% report bite

Rash for approx. 28 days if untreated

9Stages: PrimaryFlu-Like SymptomsFatigue (54%)Anorexia (26%)Myalgias (44%) and arthralgias (44%)Fever (16%)Regional lymphadenopathy (23%)Headache (42%), neck stiffness (35%)Meningeal findings absent, CSF studies normal

Stages: SecondaryRash can evolve

Days-Weeks after bite12

Stages: SecondaryCranial neuropathyMeningoencephalitisMeningeal signs typically absentCSF studies may be positive

In contrast to the primary stage, CSF studies may show a lymphocytic pleocytosis and elevated protein.Cranial neuropathy: unilateral or bilateral Bells (LMN)Also peripheral neuropathy and radiculopathy

13Stages: SecondaryMyopericarditis

Palpitations, chest pain, light-headedness, or shortness of breath.

14Stages: SecondaryAtrioventricular block

Palpitations, chest pain, light-headedness, or shortness of breath.

15

Stages: SecondaryRarelyConjunctivitisKeratitisUveitisOptic neuritisBlindness

Stages: TertiaryMonths - Years after biteJoint complaints (usually larger joints) 60% of untreated patients: monoarticular or oligoarticular arthritisExacerbations less frequent over years

Aka late disseminatedUsually knee19Stages: TertiaryLyme encephalopathyMood, memory, cognition, and sleep changesPolyneuropathyBoth have abnormal CSF studies

Polyneuropathy may also be present with radicular pain and distal parasthesias20

DiagnosisSkin findings in endemic areaELISA IgG and IgM against Borrelia (sensitivity of 89% and specificity of 72%)Many false-positivesPositive or equivocal ELISA tests may be confirmed with western blot

-Patients with a positive ELISA but a negative Western Blot do not have Lyme disease and do not require treatment. Patients with late disease uniformly have a positive Western blot. -IgM antibody titers peak six weeks after illness onset and return to normal within 10-12 weeks after the onset of symptoms. -IgM response may persist for months or years despite treatment; because IgM antibodies can persist, serologic testing for IgM is not a reliable indicator of recent inoculation.-IgG antibodies peak around 12 months and are present in late disease, but they may be detected as early as two months after the tick bite or seen in patients who have been effectively treated.-False-positive ELISA results are possible when serology cross reacts with other similar antigens, such as other Borrelial diseases (relapsing fever), spirochete infection (syphilis, gingivitis), other active infections (infective endocarditis, EBV, malaria), and autoimmune disease.-No use in culture, PCR, or urine antigen

22TreatmentTick removed within 72 hours: low likelihood of infectionTick attached for at least 36 hours: consider treatment

Treatment: Primary + Secondary StagesDoxycycline Adults: 100 mg BID for 14-21 daysChildren > 8 years: 1-2 mg/kg BID AmoxicillinPregnant or lactating: 500 mg TID for 14-21 days Children < 8 years: amoxicillin 50 mg/kg/day, divided TID (max dose of 500mg/dose)

-Cefuroxime axetil 500 mg BID for 14-21 days in adults and 30mg/kg/day divided BID for children. -Macrolides are less effective, but they can be used if the patient is intolerant or allergic to doxycycline and penicillin.

24Treatment ExceptionsCeftriaxoneLyme MeningitisSevere cardiac disease Second or third degree heart blockPR > 300 msecSymptomatic patientsAlternatives: doxycycline, penicillin G, or cefotaximeAdults: ceftriaxone 2 grams IV daily for 14-28 days Children: 75-100mg/kg/day 25Co-InfectionsBabesiosis2-40% of lyme patientsHuman granulocytic anaplasmosis (HGA).2-12% of lyme patientsDoxycycline does not treat babesiosisAmoxicillin does not treat HGA or babesiosisFever persists past 6 days: suspect co-infection

Deer tick, Ixodes scapularis can transmit other parasitic infections26BabesiosisBabesia species (especially microti)Transmitted by deer tick

Malaria-like, acute febrile illness caused by intraerythrocytic protozoal parasites of the genus BabesiaAsplenic persons, elders, and otherwise immunosuppressed patients usually have more severe disease. 27

Clinical PresentationFlu-like illness: fever, chills, headache, fatigue, and anorexiaSplenomegalyMore severe in splenectomizedSevere hemolytic anemia, hemoglobinuria, jaundiceMOD: renal insufficiency, ARDS, and DICNo meningeal signs.29DiagnosisMicroscopy of thick and thin Giemsa stainsAntibody detection through IFA stainingPCR

-Intraerythrocytic forms (piriform, ring, tetrad) -Malaria may be excluded by the absence of intracellular pigment granules, schizonts, and gametocytes-Maltese cross tetrads uncommon31TreatmentWith spleen: generally recover without treatmentSevere disease, splenectomizedClindamycin + quinine x 7-10 days ORAtovaquone + azithromycin x 7-10 days-With spleen: generally recover without treatment, although prolonged malaise and fatigue are common. -Clindamycin (1.2g twice daily intravenously or 600mg three times a day orally) plus quinine (650mg three times a day orally)-Alternative regimen that may be better tolerated, especially by children and infants: atovaquone (750mg twice daily orally) plus azithromycin (500-1000mg once followed by 250mg once a day orally)32Ehrlichioses Human granulocytic anaplasmosis (HGA)Anaplasma phagocytophilumBlack-legged tickUpper Midwest, New England, parts of the mid-Atlantic states, northern CaliforniaHuman monocytic ehrlichiosis (HME)Ehrlichia chaffeensis Lone Star tickSouth central and South eastEhrlichia ewingiiSouth central-Emerging diseases, reportable33

ANAPLASMA PHAGOCYTOPHILUM34

EHRLICHIA CHAFFEENSIS35

EhRLICHIA EWINGII36Clinical PresentationAbrupt onset of flu symptoms: fever, headache, myalgia, and shaking chillsCan see GI: N/V, diarrhea, abdominal painRashes (HME>HGA)MeningitisCarditisMODRenal failureDIC ARDS

-HME and HGA similar: Do not need to differentiate for treatment-Rash in approximately one third of patients with HME but in only 2 to 11% of those with HGA-HME Can see optic neuritisHemophagocytic lymphohistiocytosis 37DiagnosisClinicalLeukopenia, thrombocytopeniaElevated LFTs

Acute and convalescent antibodiesEnzyme immunoassay and Western blotPCR-PCR 1 week after symptoms.38TreatmentDoxycycline or tetracycline x 714 daysRifampin in children if concern for tooth staining-Doxy 100mg twice a day; 2.2mg/kg body weight given twice a day for children weighing less than 45kg-Tooth staining is no longer considered a concern for children and should not be a reason to withhold therapy39Rocky Mountain Spotted FeverRickettsia rickettsiiSoutheastern United StatesAmerican dog tick, Rocky Mountain wood tick, common brown dog tick, Lone star tickFrequently transmitted to humans by dogs

-20 species of rickettsia actually exist. RMSF only highly mortal form: 3-5% treated 30% untreated.-Endemic in all 48 contiguous states except Maine-Reportable disease-Stray dogs in Arizona is thought to be a major factor in the 70 cases and 8 deaths from RMSF reported in that state between 2003 and 200840

2013 incidence41Infection CycleInfect vascular endothelial cells and vascular smooth muscleCell-to-cell transfer via actin-based motilityDamaged endothelium with exposed subendothelium, tissue plasminogen activator, and von Willebrand's factor

-microhemorrhage, microthrombus formation, and increased vascular permeability

42

-Rash originally blanches, day 4 becomes petechiae and permanent.-Rumpel-Leede phenomenon: applying tourniquets for several minutes or taking the blood pressure may cause additional petechiae to form distal to the site of occlusion43

-Triad of fever, rash, history of tick exposure: 3% in first 3 days, 67%-Rash usually days 3-5, 4-16% without rash: rock mountain spottless fever-Should enter your meningitis ddx-CARS: Cocksackie A, Rickettsi, Syphillis44Clinical PresentationVasculitis and thrombocytopeniaEarly rash Petechial and hemorrhagic lesions MicroinfarctsSmall-vessel permeabilityHypotension, edema, and increased extravascular fluidAcute renal failure and hypovolemic shockDirect lung invasion: interstitial pneumonitisMicroinfarcts: brain, heart, lungs, kidneys, adrenal glands, liver, and spleen. Rickettsial encephalitis and diffuse microinfarcts are usual features of central nervous system involvement. Acute renal failure and hypovolemic shock, the primary causes of death, can occur as early as the second week of illness.

45DiagnosisClinicalImmunofluorescent assay and immunoperoxidase staining of R. rickettsii in rash biopsiesSerum antibody titer PCRCell culture

-Biopsy within 24 hours of antibiotic treatment46TreatmentDoxycycline Including children!Chloramphenicol Pregnant women (except those near term)For significant contraindication to tetracyclinesHigh-dose steroids in critically ill-Risk of tooth staining