Tickborne diseases / HIV (one lecture Flashcards
(48 cards)
Case: 31yo male with:
- malaise
- frontal headache
- myalgias
- mild abdominal pain
- 103F fever for 24 hrs.
- just returned from a trip to Missouri, hunted and fished. Late June. Multiple tick exposures.
- no rash, and no neck stiffness.
- What is the likely diagnosis?
likely erlichiosis
-(could be anaplasmosis as well)
most common tickborne infection in the US.
Lyme disease
which organism causes Lyme disease?
Borrelia Burgdorferi, a spirochete bacteria.
Note: Nymphs (not adults) transmit most of the disease!
Where is Lyme disease found?
Rare in Iowa but found in basically all the states North, south and east. Very rare in the Western part of the country.
What is the primary reservoir for Lyme disease?
small rodents.
What needed for transmission of Lyme?
-tick must attach to human host for AT LEASt 24 hours!! - b/c they must upregulate specific virulence genes to infect.
Findings in primary Lyme disease
systemic symptoms (fever, malaise, etc)
single, growing, targetoid rash = key. (in 80% of pt’s)
-grows a cm a day.
Findings in secondary Lyme disease
- Multiple rashes, at places all over body (away from tick bite.)
- cardiac conduction abnormalities
- neurologic: bell’s palsy, aseptic meningitis
Typically a month after exposure.
-
Findings in tertiary Lyme disease
- recurrent, migratory, oligoarticular arthritis in large joints (knee most common)
- fever usually not present, as it is a persistent infection months after initial infection.
Case: patient comes in with an erythema migrans rash, which has grown 3 cm in the last 3 days. What is the next step?
Treat for Lyme (doxycycline)!!
Don’t wait for cultures, it is a very hard organism to culture. Diagnosis is clinical and is based on H & P, along with basic lab info.
Case: patient who may have Lyme, but no rash. What is the next step?
- do an ELISA (sensitive test)
- if +, do an immunoblot to confirm.
When is serology useful for Lyme disease?
- in tertiary disease (arthritis/neuro complications)
- atypical presentation
What is the treatment for Lyme disease?
- 2-4 week regimen of Doxycycline
- usually oral med’s are sufficient
- IV doxycycline for meningitis, hospitalized cardiac manifestation.
What is babesiosis and what is it’s transmission pattern//geography?
babesiosis = poor man’s north american malaria (but not as severe as malaria).
-same vector as Lyme disease, so same geographic distribution!!
Treatment for babesiosis
NOT doxycycline!!
-more complicated therapy that we don’t need to know.
May need to co-treat for Lyme disease or Erlichiosis!!
Clinical presentation of babesiosis.
- fatigue
- low Hb
- low platelets
- evidence of hemolysis
- worse disease in those without spleen.
NO RASH!!!!!
Diagnosis of babesiosis
- blood smear or PCR
- blood smear has characteristic small, blue dots on the peripheral edges of RBCs
What is Human Granulocytic Anaplasmosis?
- intracellular rickettsia-like organisms infecting WBC’s
- anaplasmosis infects neutrophils
What is Human Monocytic Ehrlichiosis (HME)?
- rickettsia-like organisms infecting WBC’s
- erlichiosis infects monocytes.
What organism causes erlichiosis? What is it’s distribution
- ehrlichia charreensis.
- fort chaffee is in Arkansas
- hence it’s distribution is southern.
What organism causes anaplasmosis?
anaplasma phagocytophilum.
-same tick/ same geographic distribution as Lyme and Babesia
Clinical manifestations of erlichiosis and anaplasmosis
- fever
- severe headaches
- myalgias
- cough sometimes present
- rash sometimes present in erlichiosis (30% of time)
-people can get VERY sick from these infections.
How do you diagnose erlichiosis or anaplasmosis?
- Thrombocytopenia!!! = classic
- it is a clinical diagnosis
- you can do a smear but only 10-50% sensitive.
Treatment for erlichiosis and anaplasmosis
Doxycycline for 1-2 weeks.
