Tickborne diseases / HIV (one lecture Flashcards
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.
Most severe tickborne disease.
-Rocky mountain spotted fever. (25% mortality for untreated disease)
geographic distribution of Rocky Mountain Spotted Fever.
Misnomer!!
- mainly found in the midwest and southeast
- has been found in every state besides Maine, though.
epidemiology of RMSF (Rocky Mountain Spotted Fever)
- found in the midwest and southeast
- mainly in children
Pathophyisiology of RMSF
-infect endothelial cells, causing diffuse organ dysfunction - poor perfusion, hypotension, edema, organ failure
RMSF (Rocky Mountain Spotted Fever) clinical presentation. (Early and late)
-fever Early -nausea -vomiting -severe headache -muscle pain -lack of appetite -periorbital edema -edema in hands and feet
Late (several days later)
- RASH !! (macular or petechial is classic for disease)
- abdominal pain, diarrhea, joint pain
treatment for RMSF (Rocky Mountain Spotted Fever)
Doxycycline - even in kids!
-immediate treatment is important - it can be fatal.
Case: a patient with a recent tick bite develops a febrile illness and bell’s palsy. You suspect:
Lyme disease, second stage!!
Epidemiology of HIV
37 million infected and growing!
-rate of growth has slowed down the last year or so.
Risk factors for HIV/AIDS (9)
- men who have sex with men
- IV drug user
- unprotected sex with more than one partner
- unprotected sex with someone at risk for the disease
- exchanging sex for money or drugs
- receptive anal intercourse, regardless of orientation
- other STD
- transfusion or derivatives 1978-85
- asking for HIV test.
Who should be screened for HIV?
- Patients in health care settings
- pregnant women
- at high risk = test anually!!
- Note: written consent not necessary to do an HIV test.
HIV diagnostic testing.
HIV 1-2 Antigen / Antibody assay (4th generation)
- very sensitive!! (rule out HIV if negative)
- if positive, do an HIV 1/2 differentiation assay, to figure out whether it’s HIV1 or HIV2
T/F: most people who are exposed to HV do not acquire it.
True.
Median time from HIV transmission to AIDS in a given patient
10 years
CD4 T cell counts in HIV
> 500 = normal count
When does skin disease happen in HIV?
- at all levels of CD4 cells!
- seborrheic dermatitis can occur at any time, along with some other infections.
HIV manifestations in ppl with CD4 count >500
- “HIV mono” - in 40-70% of pt’s
- lymphadenopathy
- aseptic meningitis
- CNS disease (can occur at any time
- idiopathic thrombocytopenic purpura
HIV manifestations in ppl with CD4 count 200-500
- pneumonia
- candida (oral / vaginal)
- HSV
- shingles
- oral hairy leukoplakia
- seborrheic dermatitis
- lymphoma/sarcoma
Definition of AIDS
CD4
Signs of CMV retinitis
hemorrhage, yellow-inflammation on fundoscopic exam
“ketchup with scrambled eggs)”
What is Immune Reconstitution Inflammatory syndrome? (IRIS)
happens with treatment - CD4 T cell levels grow, cells wake up and attack all the stuff growing (like pneumocystis jiroveci) - causing a extreme local or systemic immune response. May need to stop therapy or use steroids to treat.
T/F: Most opportunistic pathogens in HIV are not present in most people, but low CD4 counts allow transmission
False.
-Most opportunistic infections are present in most people, but immune system keeps them at bay or eliminates them. When cell counts lower, they can grow.
-Cure is not possible for many of these infections.
Significance of viral load for HIV
-the higher your viral load, the faster you progress to AIDS (predicts RATE of disease better than CD4 count)
General treatment for HIV
ART therapy
- 3 drugs from at least 2 classes.
- be aware that treatment may have many side-effects.
Whom with HIV should be treated with ART?
Everybody with HIV!!
