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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

(73 cards)

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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
What are the 3 most life threatening diseases for travellers? Geographic distrobution?
Falciparum = 77% Typhoid - 11% Lepto 3%
26
How does borrelia evade immune system?
Has variable small proteins, and variable large proteins -Constantly changing
27
Cause of false positive and false negitive abtibody tests borriela
False positive -Cross reaction with other spirochetes (Treponema pallidum, leptospira) False negative -Antigen variation (Vsp and Vlps')
28
TBRF vs LBRF length of sx
relapses get shorter and progressively milder
29
Rickettsia - which ones causes spotted fever? Typhus? Scrub typhus?
30
What feature is often in Rickettsia but NOT scrub typhus
HypoNa
31
Rickettsia spotted fever - which species if Americas? Mediterranean / asia? Sub Saharan Africa?
R rickettsii - americas R conorii - mediiterranean R africae - sub saharan africa
32
Rash in R rickettsii
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
Rash in R. conorii
Eschar then macular rash in 97%
34
Which tics in Rickettsia africae? Rash?
Amblyomma tics Often multiple Eschars (50%) macular rash in 50%
35
Rickettsia africae vs conorri vs rickettsii Which most deadly? where found? rash?
36
cause of epidemic typhus? vector?
Rickettsia prowazekii Louse - Pediculus humanus corporis
37
Murine typhus caused by? Usual host?
R. Typhi Rattus rattus [Xenopsylla cheopis - Oriental rat flea]
38
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?
Orientia tsutsugamushi - scrub typhus - Vector: chiggers larva of mite
39
Key clue the eschar is scrub typhus (Orientia tsutsugamushi)? Systemic features that help differentiate?
In the warm places Under breast, axilla, groin, genitals Often with hearing loss / pneumonitis or CNS involvement
40
What causes Q fever? incubaton
Coxiella burnetii -Small Gram negative coccobacillus 2-6 weeks
41
Whos at high risk of Q fever?
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
Acute vs chronic Q fever
Acute - pneumonia** - Hepatitis - Flu-like illness Chronic - Endocarditis - Vasculopathy - Osteomyelitis
43
Hepatits, endocarditis and pneumonia in a farmer =? Ix?Rx?
Coxiella burnetii - Q fever IgM or IgG Doxy +hydroxychloroquine in chronic disease
44
Spot Dx
Treponema pallidum
45
Why is RPR often negative in secondary syphilis?
Prozone phenomenon
46
Patchy alopecia which bacteria do you need to consider?
Treponema pallidum
47
What features would make you confident this ulcer is syphilis even if RPR/VDRL is negative?
– 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
What am I?
Condyloma lata Treponema pallidum [Fleshy, flat-topped appearance may help distinguish from warts]
49
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]
Secondary syphilis Treponema pallidum
50
Secondary syphillis Treponema pallidum Mucous patches on background of ‘coated’ tongue
51
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?
Ocular syphilis - often causes anterior uveitis [or retinitis] IVBenpen - treat ocular as neuro
52
Define latent syphilis - what makes it early latent?
Defined by positive treponemal serology in the absence of clinical manifestation <1yr - early >1yr or unknown - late latent
53
'generalised paresis of the insane' old term for what thing that is now rarely seen?
Neurosyphilis Dementia -> paralysis
54
In syphilis why is RDR/VDRL better than serology
Differentiate present infection from past Can monitor titres and response to Rx
55
Strage thing about coxiella burnetii titres
Phase 2 indicate acute infection (not phase 1)
56
Coxiella burnetii transmission
Downwind especially of lambing raw milk, (tick bite / sex)
57
Only place with no q fever
New Zealand
58
Key risk factor for complications with Q fever
Endovascular eg prosthetic valves, aneurysms [immunosupression]
59
Q fever in pregnancy Rx? If valvuloplasty?
Co-trimoxazole throughout preg Doxy + hydroxychloroquine 12 months Chronic - Doxy + hydroxychloriquine [if prosthetic valve + surgical]
60
diagnostic Q fever
Phase 2 ELISA IgM/IgG PCR
61
How much Coxiella burnetii to be infectious? How many get chronic infection?
<10 bacteria 5% get chronic infection [40% if prosthetic valves]
62
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?
Borrelia recurrentis Louse-borne relapsing fever (LBRF) Doxy single dose (or ceftriaxone) -60% get jarisch-herxheimer reaction
63
Louse born relapsing fever transmission
contamination of broken skin/intact mucosae by coelomic fluid of lice inoculated by scratching (NOT feeding)
64
Prevent louse-born relapsing fever
Lives in clothing -> washing and hygiene
65
Name 3 louse born infections
Rickettsia prowazekii , Borrelia recurrentis Bartonella quintana [Yersinia pestis Acinetobacter baumannii]
66
Why do you get the relapsing fever in relapsing fevers
Successive appearances of Borrelia spirochaetes expressing different Variable major outer Membrane lipoProteins
67
Name 3 complications of LBRF
-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
TBRF reservoir
Humans ticks are vectors and reservoirs too
69
Difference in Rx/Distribution/neurological effects of with LBRF and TBRF
1 dose for LBRF 10 days in TBRF LBRF - horn of africa + south sudan TBRF - over world
70
Which rickettsia causes gangrene of extremities
Rickettsia prowazekii
71
Child with this lesion
Yaws (framboesia) (“framboise” French for “rasberry") Will have loads of spirochetes
72
previous ulcer then this rash? Other things they get?
Secondary yaws osteoperiostitis Hyperkeratotic plantar yaws “crab" Secondarily infected painful, lesions and cracks enforcing crab like walk on outsides edges of feet
73
- Destructive osteitis of palate and nasopharynx - Hypertrophic periostitis causing bowing of shins (sabre shin) and exostoses of the paranasal maxilla (goundou) Seen in?
Tertiary yaws

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

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