Infectious Dz - Blood Borne 3

Question 1

What causes Rocky Mountain Spotted Fever (RMSF)?

Answer 1

Rickettsia ricketsii, a gram negative, obligately intracellular bacteria

Question 2

What type of illness is RMSF?

Answer 2

An acute, febrile illness

Question 3

What is the vector (non-specific) for Rickettsia ricketsii?

Answer 3

Ticks

Question 4

Where does RMSF commonly occur in US?

Answer 4

In southeastern and south central states - where the ticks are present

Question 5

What cells does R. ricketsii infect?

Answer 5

endothelial cells by inducing phagocytosis by these cells

Question 6

Once R. rickettsii infects endothelial cells, what does it do?

Answer 6

It causes damage to the endothelial cells leading to vasculitis and increased microvascular permeability. This permeability leads to tissue edema

Question 7

Is RMSF an acute or chronic disease?

Answer 7

acute

Question 8

What will you find on PE in patients with RMSF?

Answer 8

Fever (80% of naturally infected dogs), ocular signs, splenomegaly, lymphadenomegaly, nasal discharge, tachypnea, epistaxis, petechia, ecchymoses, peripheral edema, gangrenous necrosis, orchitis and scrotal edema, CNS signs, and generalized pain This is a lot of signs, but she specifically highlighted fever

Question 9

What will you find on CBC in patients with RMSF?

Answer 9

Thrombocytopenia, leukocytosis, and mild non-regenerative anemia

Question 10

What will you find on chemistry in patients with RMSF? UA?

Answer 10

Chemistry - Hypoalbuminemia (from vasculitis) UA - variable (proteinuria, hematuria, and bilirubinuria)

Question 11

True or False: RMSF suspected patients should be treated before diagnostic test results are returned.

Answer 11

True - the tests take too long

Question 12

How is RMSF diagnosed?

Answer 12

Serology (IFA) and PCR

Question 13

How is RMSF treated?

Answer 13

Doxycycline and supportive care

Question 14

What is the prognosis for RMSF?

Answer 14

Good to excellent if diagnosed and treated early

Question 15

How is RMSF prevented?

Answer 15

with tick prevention

Question 16

Can humans get RMSF from their dogs?

Answer 16

Not exactly, they can be sentinels of tick exposure. They personally cannot give it to humans, but the ticks on the dogs can.

Question 17

Pete is a 7 YO MC Golden that has presented for a 3 day history of lethargy, inappetence, and vomiting. This is the first time in his life that he has not eaten. You practice in NC. He is on flea and HW prevention, not tick prevention. On his PE you note he has a 103.7 F fever, he is 5-7% dehydrated, there is ocular mucoid discharge in both eyes, and the fundic exam is WNL. There are prominent submandibular and prescapular LNs and a slightly stiff gait. His CBC reveals thrombocytopenia, and slight neutrophilia. The chemistry panel reveals albumin and the UA reveals a USG of 1.026 and 1+ protein.

What do you want to do next for pete?

a. He must have Babesia because he lives in the South. Start imidocarb right away.
b. Systemic workup including abdominal x-rays and ultrasound. Just because this is an infectious disease lecture doesn’t mean he has an infectious disease.
c. Culture his urine because he has a fever and proteinuria.
d. Perform a 4Dx SNAP test.

Answer 17

B, C, and D

Question 18

Which of the following doxycycline responsive infections is associated with a vasculitis that can lead to peripheral edema because the causative organism infects endothelial cells?

a. Mycoplasma haemofelis
b. Rickettsia rickettsii
c. Ehrlichia canis
d. Anaplasma phagocytophilum
e. Babesia canis vogeli

Answer 18

b. Rickettsia rickettsii

Question 19

What causes Lyme Borreliosis?

Answer 19

Borrelia burgdorferi a motile corkscrew-shaped (spirochete) bacteria

Question 20

What clinical signs are associated with lyme disease?

Answer 20

Most dogs have no signs of illness but they can have fever, arthritis, and renal disease

Question 21

In endemic areas, what percentage of dogs have been exposed to Lyme?

Answer 21

up to 80%

Question 22

What tick genus is responsible for transmitting Borellia burgdorferi?

Answer 22

Ixodes (specifically the ricinus-persulcatus complex) - this also transmits A. phagocytophilum

Question 23

What animals are reservoirs for Borellia burgdorferi?

Answer 23

Peromyscus leucopus (white-footed mouse) in the NE and upper Midwest

Question 24

How does B. burgdorferi adhere to the tick midgut?

Answer 24

Lipoprotein OspA expression

Question 25

How does B. burgdorferi bind disseminate in the mammalian host?

Answer 25

Lipoprotein OspC expression which is upregulated when a tick ingests mammalian blood

Question 26

What percentage of dogs will show overt illness signs of Lyme disease?

Answer 26

Only \<10%

Question 27

What are the clinical features of Lyme disease?

Answer 27

Fever, lameness (joint closest to tick bite is first affeced), mild to moderate thrombocytopenia, and Lyme associated nephritis

Question 28

What is Lyme-associated nephritis?

Answer 28

Membranoproliferative glomerulonephritis

Question 29

In patients that develop Lyme-associated nephritis, what is the prognosis?

Answer 29

poor

Question 30

What will the chemistry and UA show in patients with Lyme-associated nephritis?

Answer 30

Chemistry - Hypoalbuminemia +/- azotemia UA - isosthenuria and proteinuria

Question 31

Do cats get infected with B. burgdorferi?

Answer 31

They can be infected but it is unknown if there is clinical disease in cats

Question 32

How do you diagnose Lyme disease?

Answer 32

Diagnosis is difficult because 90-95% of dogs exposed to B. burgdorferi do not develop clinical disease, but serology is the best choice

Question 33

What is the best serologic test for Lyme disease and why?

Answer 33

C6 ELISA because it can differentiate between vaccination and actual exposure. If a patient has been vaccinated for Lyme disease and not actually exposed to B. burgdorferi the test will be negative. The Antech AccuPlex4 test cannot differentiate between infection and vaccination

Question 34

How is Lyme disease treated?

Answer 34

Antimicrobial treatment, but only in dogs that are seropositive will illness consistent with Lyme disease - Doxycycline

Question 35

How is Lyme nephritis treated in a stable dog (no azotemia)?

Answer 35

Doxy, ACE inhibitors, antithrombotics, reduced protein diet, Omega 3 fatty acids, and antihypertensives if needed

Question 36

How is Lyme nephritis treated in severe cases?

Answer 36

supportive care and CKD treatments

Question 37

Lyme nephritis has a better outcome with what?

Answer 37

Immunosuppression - Mycophenolate and a tapering dose of prednisolone

Question 38

What is the prognosis for Lyme disease?

Answer 38

In dogs that show no signs - great (they aren't showing signs) Lyme arthritis - rapidly recover Lyme nephritis - guarded to poor prognosis

Question 39

What Bb testing is recommended for healthy dogs?

Answer 39

Screen healthy dogs in endemic areas annually for Bb antibodies If positive, test for proteinuria so you can intervene if there is PLN, and check CBC and chemistry for cytopenias

Question 40

How is Lyme disease prevented?

Answer 40

Tick control and vaccination (recombinant vaccine is preferred although the duration of immunity is questioned)

Question 41

Which of the following is true about Lyme disease? a. It is caused by a protozoan parasite from the Apicomplexa phylum b. PCR is the best test for Lyme as it has the highest sensitivity. c. As long as you vaccinate for Lyme disease, tick control is not important d. When dogs show clinical signs of Lyme disease, fever and arthritis are the most common signs.

Answer 41

d. When dogs show clinical signs of Lyme disease, fever and arthritis are the most common signs.

Question 42

Briggs is a 6YO MC Labrador that is presenting for vomiting, lethargy, and being stiff in all four legs for the past week. On physical examination you note that he has tacky mucus membranes. The CBC showed that he is anemic and had thrombocytopenia. Chemistry revealed that he is azotemic, has hyperphosphatemia, and low albumin. His USG is 1.015 and 4+ protein in the urine. His UPC is 7.1. What do you want to do next diagnostically for Briggs? a. Culture urine b. Leptospirosis test c. 4Dx SNAP test d. all of the above

Answer 42

d. all of the above

Question 43

Briggs is a 6YO MC Labrador that is presenting for vomiting, lethargy, and being stiff in all four legs for the past week. On physical examination you note that he has tacky mucus membranes. The CBC showed that he is anemic and had thrombocytopenia. Chemistry revealed that he is azotemic, has hyperphosphatemia, and low albumin. His USG is 1.015 and 4+ protein in the urine. His UPC is 7.1. You find out that Briggs is Lyme positive and that he has a nephropathy of some sort. **What do you want to treat Briggs with?** a. Doxycycline b. Baytril, benazepril, clopidogrel, and Mycophenolate c. Doxycycline, benazepril, clopridogrel, and mycophenolate d. Doxycylcine, benazepril, clopidogrel, and cyclosportine e. Doxycycline, benazepril, and clopidogrel.

Answer 43

c. Doxycycline, benazepril, clopidogrel, and mycophenolate The 2 main drugs that should've pointed you to this answer is the doxy and the mycophenolate

Question 44

What is Briggs prognosis?

Answer 44

Guarded - since he already has azotemia he will need aggressive intervention