Rickettsia, Scrub Typhus, Q fever Flashcards

1
Q

Vector for rickettsia?

A

Arthropods: ticks, lice, mites, fleas

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2
Q

Organism for spotted fever and typhus?

A

RMSF - R.R
MSF - R.C
ATBF - R.A
MT - R.T
T - R.P

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3
Q

Symptoms of rickettsia?

A

Non specific!
Fever
Headache
Myalgias
Malaise

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4
Q

Bloods in rickettsia and scrub typhus?

A

Raised transaminases
low platelets
Low or high WCC
Low Hb
Hyponatraemia - with rickettsia

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5
Q

Organism for spotted fever rickettsia?

A

R. rickettsii - USA and S America - Rocky Mountain Spotted Fever
R. conorii - Mediterranean and Middle East, SE Asia - Med spotted fever
R. africae - Africa - African tick bite fever (mildest)

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6
Q

Key features of RMSF and organism?

A

R. rickettsii - most severe
Rash
Damage to microcirculation→hypovolemia→ gangrenous skin or digits

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7
Q

Characteristics of rash in RMSF

A

Rash - very common >90% but usually 2-3 days after start of fever
Starts in hands and feet and moves centrally
No inoculation eschar

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8
Q

Mediterranean Spotted Fever organism?

A

Rickettsia conorii

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9
Q

Painless inoculation lesion (eschar) after a bite - SINGLE - with a fever and rash in Europe, most likely diagnosis?

A

Rickettsia conorii - Mediterranean Spotted Fever
2nd most severe species

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10
Q

Organism and Vector for African tick bite fever?

A

Rickettsia africae
Amblyomma ticks

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11
Q

Presentation of Rickettsia africae?

A

Eschar, Multiple eschars
Macular rash
Lymphadenopathy

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12
Q

Where is African Tick bite fever most common?

A

Kruger National Park in South Africa.

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13
Q

Organism for epidemic typhus?

A

Rickettsia Prowazekii

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14
Q

How is typhus transmitted?

A

Lice bite and excrete faecal material

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15
Q

What is latent and reactivation of typhus called? Who gets it?

A

Recrudescent Typhus
Brill-Zinsser Disease

Advanced age
ETOH abuse
Immunosuppression
Physical Stress
Malnutrition

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16
Q

Rickettsia prowazekii - Vector?

A

Pediculus humanus corporis
Lives in clothing of cold weather clothes

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17
Q

Where is typhus most prevalent?

A

Rwanda, Burundi

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18
Q

What causes murine typhus?

A

Rickettsia typhi
(Endemic Typhus)
Coastal regions

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19
Q

R.Typhi transmitted by?

A

Rat fleas

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20
Q

Rickettsia typhi symptoms?

A

Fever, headache, myalgias ±N/V
Rash presents late - macular, starts on trunk
No eschar no bites

21
Q

Diagnosis of Rickettsia species?

A

Serology but only group specific not organism specific
PCR scrap base of eschar

22
Q

Rx of Rickettsia - all specie?

A

Doxycycline

23
Q

Organism for Scrub Typhus?

A

Orientia tsutsugamushi

24
Q

Vector for scrub typhus?

A

Vector: chiggers (larva of mite)
Reservoir: chiggers & rats

25
Q

Presentation of scrub typhus?

A

Papule forms at bite site - ulcer, eschar
6-18 d after bite, fever, headache myalgia
5 d later maculopapular rash and lymphadenopathy

26
Q

Where is Scrub typhus found?

A

S.E Asia
Has been found in Africa and S.America

27
Q

When is scrub typhus most prevalent? Incubation period?

A

Dry season, warm months, temperate regions, rural.
Up to 21 days

28
Q

Signs on examination with scrub typhys?

A

Rash, eschar - 50% have this!
Fever, myalgia, headache
HSM
Lymphadenopathy

29
Q

Odd symptoms in scrub typhus?

A

Hearing loss in one third of patients
Conjunctiva suffusion (not lepto, because diff season)

30
Q

Complications of scrub typhus?

A

Hepatitis* - main one!
Thrombocytopenia
Pneumonitis/ARDS

Elevated creatinine
CNS involvement (aseptic meninigitis/encephalitis)

31
Q

LP results with scrub typhus meningitis?

A

Raised protein
Raised WCC
Mainly Lymphocytes

32
Q

Diagnosis of Scrub Typhus?

A

PCR - particularly with eschar
ELISA for IgM/IgG

33
Q

Treatment of Scrub Typhus?

A

Doxycycline
If you add azithromycin, get less organ failure

34
Q

What organism causes Q fever?

A

Coxiella burnetti
Small Gram negative coccobacillus

35
Q

Transmission of Q fever?

A

High concentrations in placenta -> bacteria released into the air during animals giving birth -> inhaled by humans

Zoonosis – infected cattle, sheep, and goats main sources of human infection

Risks: abattoir workers, vets, farmers

36
Q

Symptoms of Q fever?

A

Acute Clinical disease but with >2(to 6) weeks incubation period

Fever, chills, fatigue
Community-acquired pneumonia - causes cough
Hepatitis

Chronic Q fever
Endocarditis
Vasculopathy
Osteomyelitis

37
Q

Generic blood results in Q fever?

A

Raised ALT/AST/Bili
Raised creatinine
Thrombocytopenia

38
Q

Most common organ affected in acute Q fever?

A

Liver

Pneumonia (and endocarditis)

39
Q

Most organ affected in chronic Q fever?

A

Culture negative endocarditis

Endocarditis, aneurysm, hepatitis, osteomyelitis

40
Q

Diagnosis of Q fever?

A

Serology (IgM screening, immunofluresence test GS)

41
Q

Rx of Q fever

A

Doxycycline
(Alternative quinolone)

42
Q

Organism and syndrome for Rickettsia, Orientia, Coxiella?

A

Coxiella - Q fever.
Orientia - Scrub typhus
Rickettsia - spotted fever

43
Q

Rx of endocarditis in Q fever

A

Long course doxy and HCQ 12-18 months

44
Q

Risk factors for Q fever?

A

Summer months, dry seasons
Around animals

45
Q

What % of acute Q fever progress to chronic?

A

<5%
Pericarditis, endocarditis, hepatitis
Can cause aneurysms
Osteomyelitis in children

46
Q

Treatment of Coxiella in pregnancy and children?

A

Co-trimoxazole
Leads to very bad outcomes in pregnancy

47
Q

Where does the chigger bite? What will you see?

A

Moist region
Necrotic eschar

48
Q

Prevention of scrub typhus?

A

Doxycycline 200mg weekly