Rickettsiae

Question 1

What are two lab clues that might lead you to suspect RMSF infection?

Answer 1

• Hyponatremia
• Thrombocytopenia

Question 2

Coxiella burnetii is what shape of bacteria? With what illness is it associated?

Answer 2

• Ricketsia
• Q fever

Question 3

What is the typical exposure story for somone infected with Q fever?

Answer 3

Works in a slaughterhouse or involved in the birthing of cattle, cats, etc.

Question 4

What is the treatment of choice for Q fever?

Answer 4

Doxycycline, regardless of age.

Question 5

True or False? Like RMSF, Q fever is a rickettsial infection.

Answer 5

True

Question 6

True or False? Like RMSF, Q fever can be treated with high dose amoxicillin.

Answer 6

False. The treatment of choice is doxy for both and especially for Q fever, regardless of age.

Question 7

This child developed this rash that started in the arms and then spread centrally. She was admitted to the hospital with fever, headache, arthralgia.

• What lab abnormalities would be consistent with RMSF?
• What is the treatment of choice?

Answer 7

• Hyponatremia and thrombocytopenia
• Doxy

Question 8

What is the organism associated with human monocytic ehrlichiosis?

Answer 8

Ehrlichia chaffeensis

Question 9

What is the organism associated with human granylocytic anaplasmosis?

Answer 9

Anaplasma phagocytophilum

Question 10

A 15 year old from Texas is seen for fever, myalgia, and has history of camping in the woods. His mother found a tick and removed it 10 days ago. He has elevated AST and ALT as well as mild pancytopenia.

• What might you see on peripheral smear that supports your diagnosis?
• What is the organism you suspect?
• What if the location was Virginia?

Answer 10

• Morulae
• Ehrlichia chaffeensis
• Anaplasma