Tick Borne Illnesses Flashcards
symptoms and presentation of babesiosis
NOT the same thing as brucellosis - which is zoonotic dx from cows)
flu like illness with hemolytic anemia and thrombocytopenia and transaminitis
how to diagnose babesiosis
by peripheral smear see Maltese cross or meroziotes arranged in tetrads in RBCs; described as “pleomorphic ring forms with pale blue cytoplasm” Thin blood smear (wright/giemsa stains) PCR = detection of babesia DNA in blood Serology: may be negative in acute infection. they do not grow well on a blood culture.
treatment of babesiosis
azithromycin + atorvaquone or
clindamycin with quinine
Can use IV abx if severe dx
remember this is the exception out of the tickborne dx treatments.
what causes babesiosis
infection with protazoan babesia microti found with same vector as lyme dx with Ixodes tick.
Rash that appears on 3rd to 5th day after onset of fever. Rash starts around ankles and wrists and involves the palms and soles and is usually petechial .
Rocky Mountain spotted fever tx with doxycycline.
treatment of early lyme dx
doxycycline should have resolution of symptoms in 2-3 weeks and rare for treatmetn failure
initial work up for suspected Lyme dx
positive ELISA IgM needs to be confirmed with a Western blot.
post lyme disease syndrome
presents with myaglias, headaches, cognitive complaints weeks to months post initial successful treatment. Treatment is supportive care.
early localized lyme disease
nonspecific viral illness with erythema migrans. can treat.
Do not get acute phase serological testing as IgM is not found until after 2-6 weeks after infection has occurred.
prophylaxis criteria for lyme dx (must meet all 5)
- attached tick is an adult or nymphal Ixodes scapularis (deer tick)
- tick attached for more than 36 hrs or engorged
- prophylaxis started within 72 hrs of tick removal
- local borrelia burgdorferi infection rate >20% (New England area)
- no contraindication to doxycycline (age <8 hrs, pregnant or lactating)
if there’s someone who has a tick found what is first step
tick removal via tweezers and protected hands by pulling straight up
erythema migrans
bull eye rash, seen after acute Lyme infection about 5-10 days after.
treatment for lyme dx prophylaxis
single dose of doxycycline 200 mg. if cannot take doxycycline or refuses most dr do not give another antibiotic. Rather would observe and then treat if EM develops
when do IgM antibodies for lyme dx develop?
2-6 weeks after and so getting ELISA and western blot may have false negatives.
if someone shows up with erythema migrans rash do they need any other testing
no do not need serological testing treat for lyme dx
Treat with doxycycline (200 mg) or cefuroxime or amoxicillin.
Rocky Mountain spotted fever presents with
nonspecific fever, headache, myalgia, arthralgia systemic symptoms followed by several days later by maculopapular petechial rash. No alopecia or LAD Can develop into encephalitis, pulmonary edema, bleeding, and shock.
Ehrlichiosis
tickborne illness seen in southeastern and mid atlantic US. fever with fatigue arthralgias and headaches and splenomegaly. see intracytoplastmic or (Morulae) inclusions affecting neutrophils or WBCs.
high fever, myalgias, headache and nausea/vomiting, LAD and AMS - see a macular or maculopapular petechial rash without central clearing in 30% of pts see intraleukocytic morulae on blood smear
Ehrlichia infection
what causes Ehrlichiosis infections and were are they located?
HGA or human granulocytic anaplamosis - anaplasma phagocytophilium Ixodes tick vector seen in northeastern and midwestern US
HME- Ehrlichia chaffeensis - lone star tick (amblyomma americanum) vector and seen in southeast and south central US with white tailed deer host. seen in spring and summer months
Ixodes tick is a vector for
lyme dx and babesiosis and Ehrlichia infections
Lab findings associated with Ehrlichiosis
leukopenia, elevated transaminases, IFA serologies peripheral blood and buffy coat exams shows intraleukocytic morulae. This infects monocytes not RBCs Can diagnosis via PCR
management of Ehrlichia infections
give doxycycline before the results of serology to come back to prevent complications like seizures and renal/respiratory failure
pt recently visited Connecticut with influenza like symptoms and erythema migrans (rash with central clearing) think:
Lyme dx
if pt is bitten by a tick and develops high fever and and maculopapular rash on trunk without central clearing and see cytopenia (low WBC and platelets) think:
coinfection with anaplasma phagocytophilium or cause of human granulocytic anaplamosis or HGA)
is Rocky Mountain spotted fever serology helpful in acute infections?
negative for first several days of infection and not helpful for making clinical decisions if concerned treat empirically cause untreated can cause death.
Rocky mountain spotted fever rash evolution
starts on ankles and wrists and spreads centrally and to palms and soles. Seen as a petechial rash
when should treatment for Rocky Mountain spotted fever start
after 5 days of symptoms can see encephalitis.
which pts are at great risk for severe Babesia infections? what are the complications for severe Babiosis infection?
greatest risk for severe Babesia infection: Asplenic pts, HIV, immune suppressed
Complications are: CHF, ARDS, DIC, AKI liver failure, splenic rupture.
anaplasma phagocytophilum is a result of
human granulocytic anaplasmsosis HGA and caused by Ixodes scapularis. See intracytoplasmic inclusions in granulocytes
how do people get babesiosis
from tick transmission (Ixodes scapularis) or blood transfusion
Where do we see babesiosis infections in the US
northern US
Risk factors for severe babesiosis infection
splenectomy, HIV, immunosuppression (cancer, organ transplant)
Mild Babesiosis
fevers, fatigue, myalgias and headache
Severe babesiosis
severe ARDS, CHF, DIC, AKI, liver failure, splenic rupture
When do you see lyme carditis?
weeks to months after infection with AV block. Doesn’t cause hypogonadism
high and prolonged fever, leukopenia, mild thrombocytopenia, mild elevated transaminases and rash only on trunk of body without central clearing is
human monocytic ehrlichiosis (HME) - from Ehrlichia chaffeensis and from lone start tick.
Human granulocytic anaplasmosis
one form of ehrlichiosis. Transmitted via the Ixodes tick (vector for Lyme and Babesiosis) and RARELY has a rash.
how do we know to test for ehrlichiosis?
clinically suspected
how to diagnosis human monocytic ehrlichiosis?
get peripheral smear which may show characteristic intracyctoplasmic inclusions (morulae) in neutrophils. Ned indirect fluoescent antibody testing with antibodies specific to ehrlichiosis to diagnose
Treatment of ehrlichiosis?
doxycycline
complications of untreated human monocytic ehrlichiosis
seizure, respiratory failure and renal failure. Increased morbidity and mortality.
high fever, myalgias, headache, nausea/vomiting, LAD and AMS and rash confined to the trunk and was out hiking. what do they have
ehrlichia infections.
difference between human monocytic ehrlichiosis and Rocky Mtn Spotted fever in presentation is that
less common to see leukopenia in Rocky mountain spotted fever. Also rash is seen in about 90% of all RMSF and starts in limbs and moves centrifugally HME - rash present sometimes and only confined to the trunk. No central clearing.
Colorado tick fever
transmitted via the tick Dermacentor andersoni and happens in western US and Canada at >4K elevation. Viral illness with similar symptoms as HME (ehrlichia) but does not develop a rash.
Babesia microti causes
babesiosis and causes high fever, hemolytic anemia and thrombocytopenia
difference in pt presentation between babesiosis and human monocytic ehrlichiosis?
babesiosis causes high fever and HEMOLYTIC ANEMIA and thrombocytopenia. NO RASH. see RBCs affected Human monocytic ehrlichiosis - severe and prolonged fever, leukopenia and thrombocytopenia.
“Early localized” lyme disease time course is from:
days to 1 month
what are symptoms of “early localized” lyme disease
erythema migrans - away from site of tick bite
“flu like” symptoms of : fatigue, headache and myalgias and arthralgias
“early disseminated” lyme disease time course is from
weeks to months
what are the symptoms of “early disseminated” lyme disease
multiple erythema migrans
unilateral/bilateral CN 7 palsy (bell’s palsy)
meningitis
carditis (AV block)
migratory arthralgias -
what is time course for “late” lyme disease?
months to years after infection
what are the presentation and symptoms of “late” lyme disease
monoarticular or oligoarticular inflammatory arthritis (affects the knee or other large joints) can have a relapsing remitting pattern.
encephalitis - can have a lyme encephalopathy too.
peripheral neuropathy
multiple erythema migrans unilateral/bilateral CN 7 palsy (Bell’s palsy) meningitis carditis (AV block) migratory arthralgias
early disseminated lyme disease
Lyme carditis presentation
asymptomatic present with palpitations (most commonly) lightheadedness, syncope, dyspnea and chest pain May show AV conduction blocks that vary between 1st and 2nd degree. There is risk for progression to 3rd degree if PR>300 msec
lyme myopericarditis presentation
self limited sometimes causes a mild pericardial effusion but rarely causes cardiomegaly. Seen in Europe but not in USA
how do we diagnose lyme disease
based on timing of how long Lyme dx is suspected:
clinical features and positive ELISA and western blot Lyme serologies
Screening test: ELISA positive (Lyme enzyme immunoassay antibody titer)
Confirmatory testing - get western blot but picking IgM o+ IgG or IgG alone depends on stage of dx
early in infection it’s recommended that Western blots for both IgM and IgG are done. IgM antibody production can predate IgG development.
later in infection >4 weeks or more of symptoms, IgG antibody is presumed a positive
after four weeks of “lyme dx” a postiive IgM western blot with negative IgG antibody is presumed a false positive result.
Thus only when there’s signs and symptoms for >30 days only get a confirmatory IgG western blot.
Treatment of early disseminated lyme dx
hospital admission with IV antibiotics with ceftriaxone to prevent long term complications and should be discharged with oral abx (doxycycline, amoxicillin, cefuroxime) for another 21-28 days
who gets treatment of early disseminated and does the treatment differ if there’s lyme carditis?
everyone with “early disseminated” gets treatment with hospital admission and IV ceftriaxone doesn’t matter if 2nd or 3rd degree or 1st degree with PR interval >300 msec. Complete AV block may need temporary pacing but these blocks are self limited and improve in one week. Lesser conduction disturbances can take up to 6 weeks to improve
Do we ever put in permanent pacemaker for pt with AV block from lyme disease
no. May need temporary pacing for 3rd degree blocks for one week but generally AV blocks are self limited. Lower grade blocks may take up to 6 weeks to resolve.
Erythema migrans is a
annular skin lesion that is painless, non pruritic and circumferentially enlarging at the initial site of tick bite. Hypersensitivity to tick saliva may present earlier with pruritic but do not enlarge significantly after onset.
incidence of lyme disease affecting neuro tissue?
15%
presentation of lyme dx affecting neuro tissue
see aseptic meningitis, facial palsy (unilateral or bilateral Bell’s palsy) and radiculopathy with skin, MSK or cardiac findings. Need a LP to rule out CNS infection (neuroborreliosis)
what is seen on Lyme aseptic meningitis CSF?
see lymphocytic pleocytosis
what is seen on Rocky Mountain spotted fever labs?
low platelets low sodium high AST and ALT
what causes rocky moutain spotted fever?
rickettsia rickettsii infeciton transmitted by tick bite peaks in the summer time and seen in the southeastern region. see low sodium, low platelets and high AST and ALT on labs
how to diagnose Rocky Mountain Spotted fever?
Rickettsia serology skin biopsy
Treatment of Rocky Mountain Spotted fever?
doxycycline
why is rocky mountain spotted fever so hard to diagnose?
35% of pts don’t know they were bitten by tick only 15% have rash at presentation a minority of them never develop a rash But will see fever, severe headache, malaise, myalgias, arthralgias and can have pulmonary edema and death and encephalitis
what to do for someone who develops a nonspecific febrile illness in spring and summer and from an edemic area with possible tick exposure
doxycycline administration early treatment for Rocky Mountain spotted fever is important because antibiotic initiation after 5 days has a higher risk for morbidity and encephalitis and gangrene of digits and death. Diagnosis is usually made after with serology or skin biopsy if there’s a rash.
what causes acute febrile illness and hemolytic anemia?
transfusion transmitted babesiosis. Blood banks do not screen for malaria or babesiosis so places that are endemic may carry Babesia.
babesosia affects
men more, pts >50 yrs those with asplenia, HIV, malignancy and develop within 1-6 weeks after tick bite
what is neuroborreliosis?
this is neurological manifestation of lyme dx that affects the CNS.
see flu like illness and erythema migranes and flu like symptoms such as fever and muscle aches.
Will see CN nerve abnormalities, altered mental status, and sensory symptoms. CAN see Bell’s palsy, MS, viral meningitis, acute disseminated encephalomyelitis
tx with penicillins, ceftriaxone, cefotaxime for 14-28 days.
how to diagnose late disseminated Lyme Dx in someone who has monoarticular arthritis (knee pain) after living in Massachusetts for many years.
two tier testing
initial test is a Lyme enzyme immunoassay antibody titer (ELISA) and it’s very sensitive. Negative test excludes Lyme dx.
confirmatory test western blot of IgM and IgG to detect antigens to borrelia burgdorferi.
NOTE confirmatory testing for IgM + IgG OR IgG only depends upon stage of Lyme dx.
early in infection- Western blots for both IgM and IgG. IgM antibody production can predate IgG development.
later in infection >4 weeks or more of symptoms, IgG antibody is presumed a positive
EXAMPLE:
after four weeks of “lyme dx” a postiive IgM western blot with negative IgG antibody is presumed a false positive result.
Thus only when there’s signs and symptoms for >30 days only get a confirmatory IgG western blot.
can get synovial fluid western blot for monoarticular arthritis.
Rule of 7’s for ruling out Lyme dx when someone has signs of aseptic meningitis
Rule used to RULE OUT LYME dx and put other diseases like enterovirus, HSV, varicella zoster and WNV on the differential.
All these rule out LYME:
headache duration <7 days,
<70% mononuclear cells,
abscence of facial nerve palsy,
aseptic meningitis with HSV2, WNV, and enterovirus would have
normal neurological exam.
