Lyme Disease/ Zoonoses Flashcards
Borreliosis presentation
- Headache
- Diffuse abdominal pain
- Fever
- Hepatosplenomegaly
- Pancytopenia
Jarsich-Herxheimer reaction
- Treating Borreliosis w/antibiotics the organism is lysed and antigen is released causing an immune response; fever, hypotension, etc.
B. Burgdorferi
- Organism that causes Lyme disease
- Replicates and resides in the midgut of an infected tick and moves through the tick’s salivary glands during feeding
- Takes 48-72hrs for organism to be transmitted
- Major phenotype switch at the bacterial surface from OspA to OspC (Outer surface proteins); the reason there is no immunity to Lyme disease
Clinical features of Lyme borreliosis
- Stage 1: Early localized (days to weeks)
*erythema migrans: often accompanied by flu-like symptoms in US, but not in Europe
- Stage 2: Early disseminated (weeks to months)
*Lyme neuroborreliosis: acute neuroligic involvement
*Carditis: 1st-3rd degree atrioventricular block
- Stage 3: Late (months to years)
*US: Lyme arthritis: arthritis in one or a few joints
*EU: Acrodermatitis chronica atrophicans: edema (purplish in color)>atrophy of the skin>local peripheral sensory neuritis, usually w/o systemic symptoms
Erythema migrans presentation
- Hallmark of early-localized Lyme disease (within 8wks of tick bite)
- Rash w/brigh-red outer border w/partial central clearing
- Systemic symptoms include: fever, arthralgia, myalgia, malaise, fatigue and lymphadenopathy
Diagnosis of Lyme disease
- Clinical- rash must exceed >5cm in diameter, show expansion and should persist for >1wk
- ELISA, hemagglutination or IFA followed by…
- Western Blot- if first test is pos. or equivocal
Rocky Mountain Spotted Fever
- Caused by gm(-) obligate intracellular Rickettsia rickettsii organism
- Most common fatal tick-borne disease in US
- Increases vascular permeability leading to edema, hypovolemis, hypotension and hypoalbunemia. Cell necrosis and occlusion of vascular lumen lead to diffuse microinfarction
- Complications: encephalitis, pulmonary edema, cardiac arrhythmia, coagulopathy, gastrointestinal bleeding, skin necrosis and hemolysis
- Cause of death: myocarditis
- Characterized by a centripetal rash, which begins on wrists, ankles and forearms and then spreads to involve the trunk
- Periorbital edema and edema of the dorsum of the hands and feet is a key diagnostic finding (18-20%)
RMSF diagnosis
- Indirect immunofluorescence or immunoperoxidase staining of skin biopsies
- Serology- (IFA) BSL-3 facility
- Lab- thrombocytopenia, hyponatremia, raised LDH
RMSF treatment
- Tetracycline and chloramphenicol
- Doxycycline (IV) is give as 100mg BID for 3D after fever subsides
Acrodermatitis Chronica Atrophicans Treatment
- Ceftriaxone
RMSF Encephalitis MRI
- “Starry sky” appearance due to perivenular infarcts (vasculitis)
How to avoid a poor outcome in the Dx and Rx of RMSF
- DON’T wait for a petichial rash to develop
- DON’T exclude the Dx b/c there is no H/O tick bite
- DON’T exclude the Dx solely for geographic or seasonal reasons
- DON’T withhold Rx if you are clinically suspicious
- DON’T be afraid to use doxycycline at any age
Human Granulocytic Anaplasmosis Presentation, Diagnosis, Management
- Vector: Ixodes scapularis
- Presentation: Fever, typically w/leukopenia, thrombocytopenia and/or increased transaminases, 6 days duration along w/chills and sweats
- Dx: blood smear displays morulae within monocytes, PCR for Anaplasma phagocytophilum DNA
- Management: Doxycycline
Human Monocytic Ehrlichiosis Presentation, Diagnosis, Management
- Presentation: dyspnea, productive cough preceded by fatigue, fever and chills,t achypneic, hypotensive, pancytopenic
- Liver enzymes elevated
- Disoriented, develops septic shock, DIC, muliorgan failure
- PE: periorbital eccymosis, subconjunctival hemorrhage
- Management: Mechanicl ventilation, blood transfusion, Rx- Doxycycline
Babesiosis Presentation, Diagnosis, Management
- Vector: Ixodes scapularis
- Presentation w/ intraerythrocytic tetrads (Maltese cross) in peripheral smear, fever, chills, night sweats and orange colored urine, hemolytic anemia, jaundice
- Diagnosis: thru blood smear; PCR for Babesia microti DNA is an alternative
*anaplasmosis and ehrlichiosis are bacterial where as this one is parasitic- can present like malaria
- Asplenic patients are more susceptible
- Management: oral quinine and IV clindamycin or atovaquone + azithromycin
