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Tropical medicine - All clinical images copyright Gorgas course - : Instituto de Medicina Tropical Alexander von Humboldt > Rickettsia, Spirochetes (borrelia, leptospirosis, syphilis), Q fever > Flashcards

Rickettsia, Spirochetes (borrelia, leptospirosis, syphilis), Q fever Flashcards

1
Q

What are the borrelia species and what do they cause?

A

Lime disease - Borrelia burgdorferi.

Relapsing fever
- Tick-borne - Borrelia hermsii, Borrelia turicatae, Borrelia parkeri
-Louse borne - Borrelia recurrentis

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2
Q

Name of louse in louse bourne relapsing fever? Organism? Basic life cycle

A

Pediculus humanus
[or P Capitis]
borrelia recurrentis

Louse bites human - gets infected with borrelia recurrentis and stays infective for life. When scratch -> crushes louse and then releases borrelia which enters through broken mucus membranes

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3
Q

2 main types of relapsing fever? Which is usually worse with hepatomegaly and jaundice? which has more relapses?

A

Louse bourne - LBRF
- Jaundice and hepatomegaly
-up to 3 relapses
-fatality rate almost 70% without Rx

Tic bourne - TBRF
- up to 11 relapses

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4
Q

Dx borriela ? rx?

A

-Blood film with Giemsa/ wright stain
-dark field microscopy [spirochaetes around 10-30um]

PCR best

Abx - Doxy best 5-10 days
ceftriaxone if meningitis

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5
Q

Who gets Jarisch-herxheimer reaction? What is it? rx?

A

Borriella treated with bacteriocidal abx Eg pencilin / ceflasporins

Life threatening - intense rigors / hyperthermia +/- shock shortly after abx

Rx with meptazinol

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6
Q

Which pathogen specifically in louse bourn relapsing fever?

A

B recurrentis

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7
Q

What causes louse-bourne typhus?

A

Rickettsia prowazekki from infected faeces of louse (pediculus humanus) which gets scratched into skin

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8
Q

Louse bourn typhus R prowazekii incubation? clinical features ? rx?

A

12 days
Fever, headache myalgia and rash (central and macular)
often get meningoencephalitis/pneumonia

they go a bit prowazzkeiii

Tetracyclines eg doxy or chloramphenicol for 1 week

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9
Q

Cause of scrub typhus?

A

Orientia tsutsugamushi
Humans infected from bites of larval mites from rodents

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10
Q

Scrub typhus incubation? features ? rx?

A

5-10 days
Eschar at the site of bite
-> headache, fever myalgia and rash
may get hepatosplenomegaly/pneumonia and delirium

Neuropsych not as pronounced as in louse bourne

Doxy

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11
Q

Cause of African tick typhus?

A

R. Africae
Found in cattle / large mammals

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12
Q

African tick typhus features ? rx?

A

-Echlar (often multiple) then central macularpapular rash

Usually self limiting but can use doxy

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13
Q

What is Weil’s disease

A

Leptospirosis with hepatic-renal failure

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14
Q

Leptospirosis life cycle

A

Small rodents and mammals - infective for live and excrete lepto in urine -> contaminates water

Enters skin though breaks or via mucosas

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15
Q

Key blood findings lepto ? dx? Rx mild vs severe?

A

Bilirubin disproportionately high
Renal function deterioration

Usually ELISA for IgM

Mild - Doxy/Azithro
Severe - IV Cef 10 days

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16
Q

Leptospirosis - when is an outbreak common?

A

Following flooding - contaminated water with rat urine

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17
Q

Leptospirosis microscopy requires? What are they? Other bug in this class?

A

Dark feild microscopy - doesnt stain
motile, aerobic spirochetes

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18
Q

Main pathogen lepto

A

Leptospira interrogans

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19
Q

Most common symptoms leptospirosis

A

Most of the infections are asymptomatic
- >90% of symptomatic illnesses
are mild

If severe:
- [Liver necrosis, tubular necrosis, meningitis, pulmonary haemorrhage

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20
Q

Lepto classic clinical progression? In weil’s where is best place to try and culture lepto? Which organs involved?

A

Biphasic symptoms
-Anicteric (non specific sx)

  • Icteric (Weils)
  • by now bacteria often not able to isolate - urine best
    Pulm / liver / renal / myocarditis
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21
Q

Key indicators in death with lepto

A

<50k platelets: OR 6.4

creatinine >200mM: OR 5.9

lactate > 2.5mM: OR 5.1

> 1000 leptospires /mL: OR 4.3

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22
Q

Name 3 Key DDx of fever with myalgia, jaundice, renal failure and thrombocytopenia

A

Leptospirosis
Malaria
Dengue
Rickettsiosis Scrub Typhus
Typhoid
fever

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23
Q

Lepto Dx?

A

RDT
Latex agglutination
ELISA
PCR

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24
Q

Lepto prevention?

A

Immunization of cattle and pets

Reduce rodent population

Chemoprophylaxis in high-risk groups - doxy

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25
Q

What are the 3 most life threatening diseases for travellers? Geographic distrobution?

A

Falciparum = 77%
Typhoid - 11%
Lepto 3%

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26
Q

How does borrelia evade immune system?

A

Has variable small proteins, and variable large proteins
-Constantly changing

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27
Q

Cause of false positive and false negitive abtibody tests borriela

A

False positive
-Cross reaction with other spirochetes (Treponema pallidum, leptospira)

False negative
-Antigen variation (Vsp and Vlps’)

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28
Q

TBRF vs LBRF length of sx

A

relapses get shorter and progressively milder

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29
Q

Rickettsia - which ones causes spotted fever? Typhus? Scrub typhus?

A
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30
Q

What feature is often in Rickettsia but NOT scrub typhus

A

HypoNa

31
Q

Rickettsia spotted fever - which species if Americas? Mediterranean / asia? Sub Saharan Africa?

A

R rickettsii - americas
R conorii - mediiterranean
R africae - sub saharan africa

32
Q

Rash in R rickettsii

A

Often not present at time of presentation (fever, malaise, myalgia, headaches)
-Starts on wrists & ankles progresses to trunk
Palms & soles (36- 82%);

NO ESCHAR

May -> gangrene of digits

33
Q

Rash in R. conorii

A

Eschar
then macular rash in 97%

34
Q

Which tics in Rickettsia africae? Rash?

A

Amblyomma tics
Often multiple Eschars (50%)
macular rash in 50%

35
Q

Rickettsia africae vs conorri vs rickettsii
Which most deadly? where found? rash?

A
36
Q

cause of epidemic typhus? vector?

A

Rickettsia prowazekii
Louse - Pediculus humanus corporis

37
Q

Murine typhus caused by? Usual host?

A

R. Typhi
Rattus rattus

[Xenopsylla cheopis - Oriental rat flea]

38
Q

Papule forms at bite site -> ulcerates, forms an eschar ,
+local adenopathy
-Usually Groin, axilla, genitals

6-18 d after bite, fever, HA,myalgias .maculopapular rash and generalized lymphadenopathy
South east Asia
Cause? Vector?

A

Orientia tsutsugamushi - scrub typhus
- Vector: chiggers larva of mite

39
Q

Key clue the eschar is scrub typhus (Orientia tsutsugamushi)?
Systemic features that help differentiate?

A

In the warm places
Under breast, axilla, groin, genitals

Often with hearing loss / pneumonitis or CNS involvement

40
Q

What causes Q fever? incubaton

A

Coxiella burnetii
-Small Gram negative coccobacillus
2-6 weeks

41
Q

Whos at high risk of Q fever?

A

abattoir workers, vets, farmers
-Cattle, sheep, goats

High concentrations in the placenta
–> bacteria released into the air during parturition
–> inhaled by humans (eg downwind epidemics)

42
Q

Acute vs chronic Q fever

A

Acute
- pneumonia**
- Hepatitis
- Flu-like illness

Chronic
- Endocarditis
- Vasculopathy
- Osteomyelitis

43
Q

Hepatits, endocarditis and pneumonia in a farmer =?
Ix?Rx?

A

Coxiella burnetii - Q fever

IgM or IgG

Doxy
+hydroxychloroquine in chronic disease

44
Q

Spot Dx

A

Treponema pallidum

45
Q

Why is RPR often negative in secondary syphilis?

A

Prozone phenomenon

46
Q

Patchy alopecia which bacteria do you need to consider?

A

Treponema pallidum

47
Q

What features would make you confident this ulcer is syphilis even if RPR/VDRL is negative?

A

– Painless / Non-tender to palpation
– Indurated, heaped-up border
– Clean (non-purulent) bas
- In the flashcard deck for spirochetes

30% RPR are negative in primary syphilis as pt has not yet seroconverted

48
Q

What am I?

A

Condyloma lata
Treponema pallidum

[Fleshy, flat-topped appearance may help distinguish from warts]

49
Q

2-6 weeks of generalized rash: macular, papular,
pustular, *vesicular
With some flat topped ‘warty’ lesions in crevices

[Fever, malaise, generalized
lymphadenophathy, alopecia, interstitial
keratitis, uveitis, liver/kidney involvement]

A

Secondary syphilis
Treponema pallidum

50
Q
A

Secondary syphillis
Treponema pallidum

Mucous patches on background of
‘coated’ tongue

51
Q

56 yo woman with HIV (CD4 716)
Eye pain, redness, photosensitivity, vision loss, retro-orbital headache, & bilateral tinnitus
* Rash over legs, palms and soles a month earlier; flat painless genital lesions
=? rx?

A

Ocular syphilis - often causes anterior uveitis
[or retinitis]
IVBenpen - treat ocular as neuro

52
Q

Define latent syphilis - what makes it early latent?

A

Defined by positive treponemal serology in the absence of
clinical manifestation
<1yr - early
>1yr or unknown - late latent

53
Q

‘generalised paresis of the insane’ old term for what thing that is now rarely seen?

A

Neurosyphilis
Dementia -> paralysis

54
Q

In syphilis why is RDR/VDRL better than serology

A

Differentiate present infection from past
Can monitor titres and response to Rx

55
Q

Strage thing about coxiella burnetii titres

A

Phase 2 indicate acute infection (not phase 1)

56
Q

Coxiella burnetii transmission

A

Downwind especially of lambing
raw milk,
(tick bite / sex)

57
Q

Only place with no q fever

A

New Zealand

58
Q

Key risk factor for complications with Q fever

A

Endovascular eg prosthetic valves, aneurysms
[immunosupression]

59
Q

Q fever in pregnancy Rx?
If valvuloplasty?

A

Co-trimoxazole throughout preg
Doxy + hydroxychloroquine 12 months

Chronic - Doxy + hydroxychloriquine
[if prosthetic valve + surgical]

60
Q

diagnostic Q fever

A

Phase 2 ELISA IgM/IgG

PCR

61
Q

How much Coxiella burnetii to be infectious? How many get chronic infection?

A

<10 bacteria

5% get chronic infection
[40% if prosthetic valves]

62
Q

20m arrived in Tripoli (Libya) from Malawi; human traffickers put him in overcrowded accommodation
shared with Somalis
+1 week developed fever lasting 5 days, resolved then another fever now
Blood film
rx?

A

Borrelia recurrentis
Louse-borne relapsing fever (LBRF)

Doxy single dose (or ceftriaxone)
-60% get jarisch-herxheimer reaction

63
Q

Louse born relapsing fever transmission

A

contamination of broken skin/intact mucosae
by coelomic fluid of lice inoculated by scratching (NOT
feeding)

64
Q

Prevent louse-born relapsing fever

A

Lives in clothing -> washing and hygiene

65
Q

Name 3 louse born infections

A

Rickettsia prowazekii ,
Borrelia recurrentis
Bartonella quintana
[Yersinia pestis
Acinetobacter baumannii]

66
Q

Why do you get the relapsing fever in relapsing fevers

A

Successive appearances of Borrelia spirochaetes expressing different Variable major outer Membrane lipoProteins

67
Q

Name 3 complications of LBRF

A

-Uterine bleeding, abortion
- Myocarditis -> acute LVF and pulmonary oedema
-Hepatic failure
- Severe bleeding (thrombocytopenia, DIC)
- Splenic infarction and rupture
- Secondary bacterial infection: (Salmonella, typhoid, Shigella , malaria, typhus, tuberculosis)
[Due to temporary immunosuppression]

68
Q

TBRF reservoir

A

Humans
ticks are vectors and reservoirs too

69
Q

Difference in Rx/Distribution/neurological effects of with LBRF and TBRF

A

1 dose for LBRF
10 days in TBRF

LBRF - horn of africa + south sudan
TBRF - over world

70
Q

Which rickettsia causes gangrene of extremities

A

Rickettsia prowazekii

71
Q

Child with this lesion

A

Yaws (framboesia)
(“framboise” French for “rasberry”)

Will have loads of spirochetes

72
Q

previous ulcer then this rash?
Other things they get?

A

Secondary yaws

osteoperiostitis

Hyperkeratotic plantar yaws
“crab” Secondarily infected painful, lesions and
cracks enforcing crab like walk on outsides edges of feet

73
Q
  • Destructive osteitis of palate and nasopharynx
  • Hypertrophic periostitis causing bowing of shins
    (sabre shin) and exostoses of the paranasal maxilla (goundou)
    Seen in?
A

Tertiary yaws

Tropical medicine - All clinical images copyright Gorgas course - : Instituto de Medicina Tropical Alexander von Humboldt (26 decks)

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