CRID 30 Part 1 + Mandell 192

Which of the following is associated with this micro finding?

• Babesia

• Anaplasma

• Ehrlichia

• Lyme

Answer explanation

this is a morula in a neutrophil

HGA = Human Granulocytotropic Anaplasmosis

more common to see morulae in HGA

CNS disease and rash more common in

• Anaplasma

• Ehrlichia

Answer explanation

CNS disease is rare in HGA

rash seen in about 40% of HME

What are the diseases that Ixodes carries?

Evaluate responses using AI:

OFF

Answer explanation

The big 3: Lyme, anaplasma, babesia

co-infections possible!

Doxy is NOT the treatment of choice for which of the following rickettsial infections

• Anaplasma

• Ehrlichia

• Babesia

• RMSF

Answer explanation

doxy is your go to for most rickettsial infections with a notable exception being Babesia: atovaquone + azithro (clinda and quinine in severe cases)

other important ones to remember: tularemia (streptomycin + gent), viral causes

32 year old male comes to the ED for evaluation of fever and myalgia. he recently returned from a trip to upstate NYC where he did alot of hiking. he initially attributed his sxs to just being tired from all the hiking, but he does recall several tick bites and decided to get checked. He is not critically ill-appearing. he has a fever of 100.9, HR 110, normotensive. exam notable for mild abdominal tenderness and myalgia; no rash. Labs notable for WBC 2.3, Hgb 10.2, mild AKI and transaminitis, elevated LDH, low hapto. which of the following are you most suspicious for?

• RMSF

• Ehrlichia

• STARI

• Babesia

Answer explanation

babesia infects erythrocytes, so hemolysis is a common finding

can also see hemolysis/anemia with RMSF, but would also usually see a rash and patients are often pretty sick (high fever, HA), unlike this patient

Wrong location for stari

26 year old female presents to the ED for 2 days of fever and lethargy. She recently was visiting family, and did some camping in Minnesota ~7 days ago. She started feeling fatigued with associated fever to 101, chills, headache, myalgias, n/v, and a pinkish rash. she is tachycardic to 120 and hypotensive with plans to admit to the ICU. Patients sister states they all got bit by ticks while camping, but no one else is having any rashes or sxs. she is started on empiric abx (including doxy). since you are concerned about RMSF, what testing do you ask the primary team to order?

• no testing needed

• serology

• PCR

• biopsy the rash

Answer explanation

While testing wont change management in an acutely ill patient, testing is still recommended. all of the listed answer choices are ways that RMSF can be diagnosed, but the preferred way (highest sensitivity and specificity) is indirect fluorescent antibody (IFA) test for immunoglobulin G (IgG) using R. rickettsii antigen. IgG IFA assays should be performed on paired acute and convalescent serum samples collected 2–10 weeks apart to demonstrate evidence of a fourfold seroconversion.

IgG often negative early in infection. IgM may be available in some labs, but this test is less specific

a single negative test isnt enough to rule out infection

40 year old male presents to the ED for rash, fever, headache, and weakness x2 days. he just got back from a fishing trip in Florida where he states he did find some ticks on his clothing, but is unsure about bites. he has associated nausea, vomiting, and myalgia. he is febrile to 102 in the ED and has the pictured rash. he appears uncomfortable but not toxic. he is being admitted to the regular medicine ward for further eval. given the travel hx, rash, and tick exposure, you recommend starting doxy to treat infection caused by

• R. parkeri

• R. rickettsii

• R. prowazakii

• R. akari

Answer explanation

spotted fever due to R parkeri - caused by gulf coast tick (A. maculatum)

very similar to RMSF but can be seen year round given different loacale and disease often less severe. there is also often a "tache noir"

other rickettsia's are not tick borne

a 55 year old man experiencing homelessness presents to the ED for fever, drenching sweats, myalgias/joint pain. he states he has had similar episodes like this in the past few months but seems to always get better. on exam you note some mild abdominal tenderness and hepatosplenomegaly. patient appears disheveled, but not acutely ill. no rash is present, but nursing states they saw body lice and removed a tick from his scalp. he is febrile to 101, HR 108, BP normal. labs notable for WBC 4, Hgb 10, plt 100. what might you expect to see on blood smear (prepped however you wish) for this patient

• maltese crosses

• morulae

• rings

• spirochetes

Answer explanation

tickborne relapsing fever

clinically similar to louseborne relapsing fever, just different vector: soft tick vs body louse

this syndrome is caused by a variety of spirochetes: B. recurrentis, Borrelia hermsii, and Borrelia parkeri are the main ones to remember

Giemsa stain of a blood smear can show spirochetes, but PCR is preferred for dx

Tx is doxy unless neuro sxs then ceftriaxone

34 year old female presents to the ED for rash. she states she recently returned from a vacation to the Ozarks where she stayed in a cabin. she was outdoors doing various activities like hiking, swimming, boating, etc. she recalls several tick and mosquito bites, but only has the pictured rash around where she had a tick that she removed about a week ago. she thinks the rash has gotten slightly bigger over the last couple days. she otherwise feels well, aside from some minor fatigue and a mild HA. Tx?

• doxy

• no tx

• atovaquone

• keflex

Answer explanation

STARI (Amblyomma americanum)- similar to lyme clinically but different geographic location and doesn’t have the same long term sequelae

sometimes the rash has central clearing after a

few days.

dx is clinical - there aren’t any tests to dx

tx - per the CDC, its unknown if treatment helps or is needed. patients often get doxy because there is concern for lyme often times.

22 year old female living in upstate New York presents with her roommate in July with fever x4 days now with confusion. per the roommate, the patient spends a lot of time outdoors but does not recall that she c/o any bug bites recently. She is febrile on exam to 102, mild tachycardia but otherwise HDS. no neck stiffness but is lethargic on exam. no rash noted. CBC and CMP are normal. LP is pursued and shows WBC 130, normal glucose, protein 65 (high). Dx?

• Lyme

• Anaplasmosis

• Powassan Virus

• Babesiosis

Answer explanation

Powassan virus (Nypmphal ixodes scapularis) often causes encephalitis and is seen mostly in the north east (esp NY), WI, MN, Canada.

test CSF for viral IgM. treatment supportive

the other answer choices you would expect to see some sort of combination of the classic leukopenia, thrombocytopenia, transaminitis, and possibly a rash