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Flashcards in Rickettsial Diseases Deck (47):
1

Rickettsia
Size?
Gram?
Movement?
Shape?
What are the similar to?

Small
Gram-negative
Non-motile
Rod-to-coccoid-shaped bacterium
Similar to Chlamydia

2

Rickettsiae
Pathology?

--Obligate intracellular bacterial parasites (steal ATP)
--They are unable to produce sufficient energy to replicate extracellularly

3

Rickettsia Transmitted how?

Where do they grow?

Human infection results from what? 2

How do they travel thrpughut the body and what are they specifically infecting?

Require an arthropod vector (except for Q fever)

In arthropods (insects), rickettsiae grow in the gut lining, often without harming the host.

Human infection results from either an
1. arthropod bite or
2. contamination with its feces

Circulate widely in the bloodstream (bacteremia)

Infecting endothelium of the blood vessel walls.

4

Pathophysiology of Rickettsial disease:

Rickettsia has a tropism for ?

WHy do you get damage in the endothelial lining?

Damage to the vessels of the skin results in?

Most Rickettsia cause what?
4


endothelial cells that line blood vessels


Inflammation from the infection of the endithelial
cells

the characteristic rash

1. rashes,
2. high fevers, and
3. bad headaches,
4. arthralgia,

5

What kind of rashes would you see in Rickettsia?
2

Vasculitis
Petechiae, purpura

6

How is the diagnoses made for Rickettsia?

Confirmation of your clinical diagnosis will be based on?

HISTORY OF INSECT BITE

measuring immunological titers to the infecting organism, and this may take weeks to develop

7

Health care providers MUST
know what about Rickettsia epidemiology?
2

1. Know what types of insects reside in your community
2. What types of ARTHROPOD-borne diseases have been reported in your community

8

Rocky Mountain spotted fever:
Pathogen?
Geography?
Insect/Vector?
Other carrier?

Rickettsia rickettsii

Western Hemisphere United States (especially mid-Atlantic coast)

Tick

Rodents, dogs

9

RMSF onset of symtpoms?
4

When will the rash appear?

Describe the progression of the rash? 2


Acute onset of nonspecific symptoms, e.g.,
1. Fever,
2. severe headache,
3. myalgias, and
4. prostration.

Rash appears 2–6 days later,

1. Macules that frequently progress to petechiae.
2. The rash usually appears first on the hands and feet and then moves inward to the trunk

10

Work up for RMSF?
4

1. CBC
2. Chemistry panel
3. May need spinal tap to study CSF and (rule out meningicoccus)
4. blood cultures (rule out)

11

In your differential diagnosis what might the RMSF rash be confused with?
4

1. measles,
2. typhoid,
3. ehrlichiosis, or most importantly
4. meningococcemia.

12

Delay in RSMF treatment can lead to what?

severe disease and fatal outcome

13

What will you see on the CBC and chem panel for RMSF?
3

1. aminotransferases (liver enzymes)- hyper bilirubin
2. thrombocytopenia
3. hyponatremia

14

What will you find in the CSF for RMSF? 3

Low glucose
high whote count

could lead to DIC

15

RMSF is susceptible to what kind of antibiotics?

Treatment length?

Susceptible to tetracycline-class antibiotics
Doxycycline is considered the therapy of choice in nearly all clinical situations.

at least 3 days after the fever subsides and until evidence of clinical improvement is noted, which is typically for a minimum total course of 5--7 days.

16

What types of ticks will spread RMSF?
2

Dog ticks
Deer ticks

17

Epidemic Louse-borne typhus is caused by what?
This is a parasite of the body louse

Rickettsia prowazekii

18

Symptoms and Signs of Epidemic Louse-Borne Typhus

Prodromal symtpoms?
Incubation period?

Describe the onset (timing and symptoms of the acute illness stage)?
4

Prodromal
1. malaise,
2. cough,
3. HA,
4. arthralgias and
5. CP
during incubation period of 10-14 days

Abrupt onset of
1. chills, high fever, and
2. flu-like symptoms progressing to
3. delirium and
4. stupor

19

Laboratory findings of Epidemic Louse-Borne Typhus
3

What will be varibale?
What will be low?
What will be elevated?

What will be evident in the urine?

What will you see on the CT?

CBC
CMP
CXR


White count can be variable
thrombocytopenia
elevated liver enzymes

hematuria (kidneys not working)

CT (patchy consolidation)

20

R prowazekii can survive in what for primary infection and years later what can happen?

What is this known as?

R prowazekii can survive in lymphoid tissues after primary infection, and

years later, produce recrudescence of disease

This phenomenon can serve as a point source for future outbreaks

Brill-Zinsser Disease

21

How is the onset and symptoms different in Brill-Zinsser Disease
than in priimary infection?

3

1. More gradual onset than primary,
2. fever and rash are of shorter duration, and the
3. disease is milder and rarely fatal

22

Treatment of Epidemic Louse-Borne Typhus
2

Doxycycline
Chloramphenicol

23

Contraindications of DOXY
3

kids under 8
pregnant
lactating

24

Endemic (Murine) Typhus
is caused by what bacteria?

Transmitted how?
What areas is it most common in?

Describe onset and symtpoms? 3

Labs, Dx, and Tx really the same as for?

What is a good thing about this infection?

Rickettsia typhi

Transmitted from Rat to Rat via the rat flea
Urban

Gradual onset, less severe symptoms, and a shorter duration of illness than epidemic typhus

Labs, Dx, and Tx really the same as for Epidemic Louse-Borne Typhus

It can provide us immunity

25

Rickettsialpox
is caused by what bacteria?

Transmitted how?

Describe onset and symtpoms?

Rickettsia akari

Transmitted to humans via mites that ride on mice

Onset 3-5 days later

Mild, self-limited, febrile illness that starts with an initial localized red skin bump

26

What do the bumps in Rickettsialpox turn into?

What does Rickettsialpox have a dramatic response to?

Bump turns into a blister,and days later fever and HA develop, and other vesicles appear over the body

Dramatic response to Doxycycline!

27

Q FEVER is caused by what kind of infection?

Coxiella burnetii

28

Coxiella burnetii is gram what?


Who does it infect? 3

How is it spread to humans often? 2

What is dangerous about this disease?

Gram-negative intracellular organism

Infects cattle, sheep, and goats

In man = Q Fever, animal tissue is aerosolized or ingestion of contaminated milk

Highly resistant spore stage that is transmitted to humans when animal tissue is aerosolized or ingestion of contaminated milk

29

What is the only one where you dont need an arthropod to transmit the disease?

It is also the one that doesnt cause a fever and a rash?

What does it cause?

Q FEVER: Coxiella burnetii

Pneumonia

30

Q FEVER: Coxiella burnetii
Begins suddenly with what symtpoms?

Begins suddenly with fever, severe headache, cough, and other influenza-like symptoms.

31

Combinaiton of what is eough to diagnose Q feve?

Hepititis and Pneumonia

32

Q fever is an acute disease and recovery is expected how?

even in the absence of antibiotic therapy.

33

Q FEVER: Coxiella burnetii Laboratory Findings
4

CBC
CMP
CXR
Echo

34

Q FEVER: Coxiella burnetii
What is special about the chest Xray?

Lots of pathy infiltrates
more serious than the physical signs suggest (what else is this in? mycoplasma pneumonia)

35

Q FEVER: Coxiella burnetii
Treatment and Prognosis? 2


Whats the biggest complication with this disease?

Doxycycline
Even when untreated, mortality rate is low unless endocarditis develops

Hydroxycholorquine

Endocarditis

36

Lyme disease is what kind of bacteria (shape?)

What bacteria causes it?

Actually a spirochete, but put here because it is the other main tick transmitted disease you will see
Corkscrew-shaped, but larger than Treponema

Borrelia burgdorferi

37

What kind of tick causes it?

How long does it take to transfer infection?

Similar to what disease?

Ixodes tick

Takes 24 hours to transfer infection

Similar to Syphilis

38

Clinical findings of lyme disease?
5

1. joint illness
2. malaise
3. headache
4. lympadenopathy
5. if you think something is lupus you have to culture for lyme disease first

39

Diagnosis/ Lab tests to do fro lyme disease?
3

1. If ECM, leading edge of rash biopsied
2. Culture is very difficult, usually use levels of anti-Borrelia burgdorferi antibodies to help make diagnosis
3. ELISA and Western Immunoblotting

40

Lyme disease treatment?
2

Doxycycline or penicillin family antibiotics are currently the most effective abx for treating the disease

41

If you have pt with what symtpoms you should think Rickettsia/tick borne disease?
3

high fevers, arthralgias, and especially rashes

42

In what diease will the rash start at wrists, ankles, soles and palms and spreads to the trunk?

RMSF

43

Lyme disease identifying entity?

Erythema chronicum migrans

44

Diff for RMSF?
3

syphillis
Menigitis
Hand foot and mouth disease

45

Epidemic (Louse-Borne) Typhus
Pathogen?
Geography?
Insect/Vector?
Other carrier?

Rickettsia prowazekii

Central and Northeastern Africa, Central and South America

Louse

Human Body
Flying Squirrels (Yes, this is not a joke!)

46

Endemic (murine) typhus
Pathogen?
Geography?
Insect/Vector?
Other carrier?


Rickettsia typhi

small focus (United States: southeastern Gulf

Flea

Rodents

47

Rickettsial pox (causes an eschar)
Pathogen?
Geography?
Insect/Vector?
Other carrier?


Rickettsia akari

United States

Mite

Mice