Term
| What is a clinical characteristic of Rickettsia? |
|
Definition
typically cause fevers with a rash
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Term
| How is Rickettsia transmitted? |
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Definition
| host is infected by an insect bite |
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Term
What is the pathogenesis of Rickettsia?
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Definition
| infection of vascular endothelium results in RBCs leaking from the vessels and causing a rash and petechial lesions; this same process in organs causes systemic symptoms |
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Term
| What is the ideal way to diagnose Rickettsia and why is culture not used? |
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Definition
| PCR; culture is difficult and hazardous |
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Term
| What are good versus bad serologic tests for Rickettsia? |
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Definition
good: ELISA
bad: Weil-Felix agglutination tests (insensitive and non-specific) |
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Term
| What organism causes Rocky Mountain Spotted Fever in the rest of the world? |
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Definition
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Term
| In what age group does Rocky Mountain Spotted Fever usually occur? |
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Definition
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Term
| What are the clinical manifestations of Rocky Mountain Spotted Fever? |
|
Definition
- incubation: 2-14 days
- fever, headache, confusion, myalgia
- rash by 2nd or 3rd day
- appears on wrists and ankles, may spread to trunk
- key if on PALMS AND SOLES
- death in 25% w/o treatment
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Term
| What is important about diagnosing Rocky Mountain Spotty Fever? |
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Definition
| must make clinical diagnosis- too late to treat if you wait for laboratory confirmation! |
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Term
| What disease does Rickettsia akari cause and where is it most common? |
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Definition
| Rickettsialpox, in NY and poorer sections of other large cities |
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Term
| What causes scrub typhus and where is it most common? |
|
Definition
| Rickettsia tsutsugamushi, Asian and South Pacific |
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Term
| In what disease are the vectors forever infected, and why? |
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Definition
| rodent mites (Scrub typhus) remain infected forever by transovarian transmission |
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Term
| What causes Louse-borne typhus fever? |
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Definition
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Term
| What are the symptoms of typhus fever? |
|
Definition
| fever, headache, confusion, myalgia, rash |
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Term
| What are possible complications of typhus fever and what is called when it relapses? |
|
Definition
- heart and CNS
- recrudescent typhus (Brill's disease) |
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Term
How long can Rickettsia remain dormant and where?
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|
Definition
| 10-40 years, in reticuloendothelial cells |
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Term
| What causes murine typhus? |
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Definition
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Term
| What is the difference between Murine typhus and Rickettsialpox? |
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Definition
| Murine is carried in urban areas by a rat flea, rickettsialpox is carried in urban areas by the house mouse mite |
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Term
| How is Coxiella burnetii different from other Rickettsiae in regards to mode of transmission and clinical presentation? |
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Definition
| It is spread via aerosol, does not present with a rash |
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Term
| Which rickettsial organism grows in placental tissue of sheep, goats, and cattle |
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Definition
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Term
| What people are most likely to contract Q fever? |
|
Definition
| researchers, vets, slaughter house workers, ranchers |
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|
Term
| What is the incubation period and symptoms of Q-fever? |
|
Definition
9-20 days
- fever, chills, headache, no rash!
- mild pneumonia
- liver, abnormal LFTs
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Term
| What are some occasional complications of Q fever? |
|
Definition
| endocarditis, encephalitis, pericarditis |
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Term
| What causes human monocytic ehrlichiosis? |
|
Definition
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|
Term
| What are the symptoms of human monocytic ehrlichiosis? |
|
Definition
| fever, hypotension, confusion, renal failure, pancytopenia, GI hemorrhages, hepatocellular injury |
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Term
| What is a morula inclusion in a mononuclear cell from the CSF indicative of? |
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Definition
| Ehrlichia chaffeensis infection |
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Term
| What organism causes human granulocytic anaplasmosis? |
|
Definition
| Anaplasma phagocytophilia |
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Term
| What are symptoms of human granulocytic anaplasmosis? |
|
Definition
| fever, chills, headache, muscle ache, nausea, vomiting, elevated LFTs, decrease in platelet and WBC count |
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Term
| What is the mortality rate for human granulocytic anaplasmosis and what does it result from? |
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Definition
| 5% mortality: kidney failure, meningitis |
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Term
| What are symptoms of Trench fever? |
|
Definition
| fever, rash, bone pain, splenomegaly, can be mild to severe |
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Term
| What causes urban trench fever and what is target population? |
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Definition
| Bartonella quintana, disease of the homeless (esp. alcohol males) |
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Term
| What are the symptoms of cat-scratch disease? |
|
Definition
| blister at site of inoculation in 3-10 days, lymph nodes swell and become tender, disappear in 2-6 months -> lifelong immunity |
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Term
| What is the severe systemic variation of cat-scratch fever called and what population is most at risk? |
|
Definition
| Bacillary angiomatosis: AIDS patients |
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Term
| How is cat-scratch fever commonly diagnosed? |
|
Definition
| antibody titer or PCR test (not culture) |
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