Rickettsia, Scrub Typhus, Q fever

Question 1

Vector for rickettsia?

Answer 1

Arthropods: ticks, lice, mites, fleas

Question 2

Organism for spotted fever and typhus?

Answer 2

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

Question 3

Symptoms of rickettsia?

Answer 3

Non specific!
Fever
Headache
Myalgias
Malaise

Question 4

Bloods in rickettsia and scrub typhus?

Answer 4

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

Question 5

Organism for spotted fever rickettsia?

Answer 5

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)

Question 6

Key features of RMSF and organism?

Answer 6

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

Question 7

Characteristics of rash in RMSF

Answer 7

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

Question 8

Mediterranean Spotted Fever organism?

Answer 8

Rickettsia conorii

Question 9

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

Answer 9

Rickettsia conorii - Mediterranean Spotted Fever
2nd most severe species

Question 10

Organism and Vector for African tick bite fever?

Answer 10

Rickettsia africae
Amblyomma ticks

Question 11

Presentation of Rickettsia africae?

Answer 11

Eschar, Multiple eschars
Macular rash
Lymphadenopathy

Question 12

Where is African Tick bite fever most common?

Answer 12

Kruger National Park in South Africa.

Question 13

Organism for epidemic typhus?

Answer 13

Rickettsia Prowazekii

Question 14

How is typhus transmitted?

Answer 14

Lice bite and excrete faecal material

Question 15

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

Answer 15

Recrudescent Typhus
Brill-Zinsser Disease

Advanced age
ETOH abuse
Immunosuppression
Physical Stress
Malnutrition

Question 16

Rickettsia prowazekii - Vector?

Answer 16

Pediculus humanus corporis
Lives in clothing of cold weather clothes

Question 17

Where is typhus most prevalent?

Answer 17

Rwanda, Burundi

Question 18

What causes murine typhus?

Answer 18

Rickettsia typhi
(Endemic Typhus)
Coastal regions

Question 19

R.Typhi transmitted by?

Answer 19

Rat fleas

Question 20

Rickettsia typhi symptoms?

Answer 20

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

Question 21

Diagnosis of Rickettsia species?

Answer 21

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

Question 22

Rx of Rickettsia - all specie?

Answer 22

Doxycycline

Question 23

Organism for Scrub Typhus?

Answer 23

Orientia tsutsugamushi

Question 24

Vector for scrub typhus?

Answer 24

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

Question 25

Presentation of scrub typhus?

Answer 25

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

Question 26

Where is Scrub typhus found?

Answer 26

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

Question 27

When is scrub typhus most prevalent? Incubation period?

Answer 27

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

Question 28

Signs on examination with scrub typhys?

Answer 28

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

Question 29

Odd symptoms in scrub typhus?

Answer 29

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

Question 30

Complications of scrub typhus?

Answer 30

Hepatitis*** - main one! Thrombocytopenia Pneumonitis/ARDS** Elevated creatinine CNS involvement (aseptic meninigitis/encephalitis)

Question 31

LP results with scrub typhus meningitis?

Answer 31

Raised protein Raised WCC Mainly Lymphocytes

Question 32

Diagnosis of Scrub Typhus?

Answer 32

PCR - particularly with eschar ELISA for IgM/IgG

Question 33

Treatment of Scrub Typhus?

Answer 33

Doxycycline If you add azithromycin, get less organ failure

Question 34

What organism causes Q fever?

Answer 34

Coxiella burnetti Small Gram negative coccobacillus

Question 35

Transmission of Q fever?

Answer 35

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

Question 36

Symptoms of Q fever?

Answer 36

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

Question 37

Generic blood results in Q fever?

Answer 37

Raised ALT/AST/Bili Raised creatinine Thrombocytopenia

Question 38

Most common organ affected in acute Q fever?

Answer 38

Liver Pneumonia (and endocarditis)

Question 39

Most organ affected in chronic Q fever?

Answer 39

Culture negative endocarditis Endocarditis, aneurysm, hepatitis, osteomyelitis

Question 40

Diagnosis of Q fever?

Answer 40

Serology (IgM screening, immunofluresence test GS)

Question 41

Rx of Q fever

Answer 41

Doxycycline (Alternative quinolone)

Question 42

Organism and syndrome for Rickettsia, Orientia, Coxiella?

Answer 42

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

Question 43

Rx of endocarditis in Q fever

Answer 43

Long course doxy and HCQ 12-18 months

Question 44

Risk factors for Q fever?

Answer 44

Summer months, dry seasons Around animals

Question 45

What % of acute Q fever progress to chronic?

Answer 45

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

Question 46

Treatment of Coxiella in pregnancy and children?

Answer 46

Co-trimoxazole Leads to very bad outcomes in pregnancy

Question 47

Where does the chigger bite? What will you see?

Answer 47

Moist region Necrotic eschar

Question 48

Prevention of scrub typhus?

Answer 48

Doxycycline 200mg weekly