Tick Transmitted Diseases

Question 1

Three main causes of petechiae

Answer 1

Thrombocytopenia
Endothelial dysfunction
Thrombocytopathia

Question 2

Common blood chemistry protein pattern for systemic inflammation

Answer 2

Hypoalbuminemia
Hyperglobulinemia

Question 3

4 main causes for thrombocytopenia

Answer 3

Sequestration
Decreased production
Utilization
Destruction (immune-mediated)

Question 4

Which tickborne disease is associated with bone marrow suppression?

Answer 4

Ehrlichia canis

Question 5

CME

Answer 5

Canine monocytes ehrlichiosis

Question 6

Transmission and distribution of Ehrlichia canis

Answer 6

Brown dog tick
Found across U.S

Question 7

Three potential phases of CME

Answer 7

1) Acute phase (8-20d after inoculation)
2) Chronic phase (bone marrow hypoplasia)
3) Subclinical phase

Question 8

What are some major CS you see with acute CME?

Answer 8

• Fever, lethargy, and inappetence
• Lymphadenomegaly and hepatosplenomegaly
• Thrombocytopenia and thrombocytopathia

Question 9

T/F: Patients with acute CME can spontaneously recover

Answer 9

True - may recover after 2-4 weeks or remain subclinically infected

Question 10

Major CS associated with chronic CME

Answer 10

Bone marrow hypoplasia (pancytopenia)

Marked lymphocytosis (Ddx lymphocytic leukemia)

Bone marrow plasmacytosis (hyperglobulinemia)

Question 11

T/F: You can differentiate E. Canis and E. Chaffeenis using a blood smear

Answer 11

False - morulae in monocytes or lymphocytes can be visualized in both

Question 12

What test is the gold standard for diagnosing E. Canis?

Answer 12

IFA test looking for IgG antibodies

Question 13

When is PCR testing the most helpful?

Answer 13

When you suspect acute infections

Body hasn’t created antibodies

Can be detected as early as 4-10d

Take sample before starting abx

Question 14

Drug of choice for E. Canis

Answer 14

Doxycycline

Can also use Minocycline or Chloramphenicol

Question 15

Two big categories of polyarthropathies

Answer 15

• Non-erosive polyarthritis (IM or septic)
• Erosive polyarthritis

Question 16

Differentials for morula in neutrophils

Answer 16

Anaplasma phagocytophilium
Ehrlichia ewingii

Question 17

What cell does Ehrlichia ewingii chill out in?

Answer 17

Neutrophils

Question 18

Transmission and distribution of Ehrlichia ewingii

Answer 18

Lone Star tick (Amblyomma americanum)
South-central and Southeastern U.S.

Question 19

T/F: Ehrlichia ewingii can present both acutely and chronically.

Answer 19

False - only causes acute disease

Question 20

T/F: Ehrlichia canis is typically more severe than Ehrlichia ewingii

Answer 20

True

Question 21

Your patient tests positive on a snap test for Ehrlichia canis. What other species of Ehrlichia could this patient have?

Answer 21

Ewingii
Chaffeenis

Question 22

T/F: Cats can be affected by Anaplasma phagocytophilium

Answer 22

True

Question 23

Transmission of Anaplasma phagocytophilium

Answer 23

Ixodes species

Question 24

RMSF

Answer 24

Rocky Mountain Spotted Fever (Rickettsia rickettsii)

Question 25

Transmission of RMSF

Answer 25

Dermacentor species

Question 26

Where do Rickettsia rickettsii replicate?

Answer 26

Endothelial cells

Question 27

Why might patients with RMSF hemorrhage excessively or experience thrombosis?

Answer 27

B/c Rickettsia rickettsii replicate in the endothelial cells, a vasculitis is initiated Vasculitis triggers platelets and coagulation cascade which leads to consumption of platelets and coagulation factors

Question 28

Incubation period for R. Rickettsii

Answer 28

2-14d

Question 29

Common CS of RMSF

Answer 29

Arthralgia and spinal hyperesthesia Thrombocytopenia Cutaneous edema and hyperemia Neurologic signs Lots of other signs

Question 30

What drugs can be used to treat RMSF?

Answer 30

Doxy Chloramphenicol Enrofloxacin

Question 31

Hepatozoon americanum is transmitted via

Answer 31

Ingestion of Amblyomma maculatum

Question 32

Common CS of H. Americanum

Answer 32

Severe muscle wasting Generalized hyperesthesia Stiff gait Purulent ocular discharge CS can wax and wane

Question 33

Periosteal bone proliferation can result from

Answer 33

Hepatozoonosis

Question 34

What is the most reliable way to diagnose hepatozoonosis?

Answer 34

Skeletal muscle biopsy showing “onion” cysts and marked pyogranulomatous myositis

Question 35

T/F: H americanum can be treated with doxycycline

Answer 35

False - treated with TCP combination therapy (TMS, Clindamycin, and Pyrimethamine) After TCP therapy, start decoquinate and continue for 2y