21 - Rickettsial Disease Flashcards

1
Q

What is a “rickettsia organism”?

A

A middle ground between bacteria and viruses

- obligate intracellular gram-neg coccobacilli

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2
Q

Gram stain for rickettsia?

A

Doesnt stain well with gram stain

RED if stained with giemsa stain

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3
Q

Transmission of rickettsial disease?

A

Usually arthropods to humans

- except Q fever

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4
Q

3 Subgroups of rickettsial disease?

A
  1. Spotted fever group
    - rocky mountain spotted fever
  2. Typhus group
    - louse-borne typhus
    - brill-zinsser disease
    - maurine typhus
  3. Other
    - ehrlichiosis
    - cat scratch disease
    - trench fever
    - scrub typhus
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5
Q

Pathophysiology of rickettsial disease?

A

Multiply’s in the endothelial cells

Focal area is the site of infection but it then Hits the blood stream

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6
Q

Organs that are effected by rickettsial disease

A

Can affect all organs but

Most readily fond in the skin and adrenals

Common sites

  • CNS
  • Heart
  • Liver
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7
Q

Common tx for rickettsia?

A

Doxy

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8
Q

Louse borne typhus is caused by?

A

Rickettsia prowazekii

Spread by lice (pediculus humanus)

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9
Q

Epidemics of louse borne typhus are common in?

A

Europe
Asia
Africa

  • associated with overcrowding
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10
Q

Louse borne typhus s/s?

A
Abrupt onset 
- 1-2 wks after exposure
Fever
HA
Rash
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11
Q

Louse borne typhus rash?

A

Presents on days 4-7

TRUNK -> extremities
- opposite of RMSF

Spares the face, palms and soles

Macules -> maculopapules -> petechiae

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12
Q

Complications of louse borne typhus?

A
Gangrene
Pericarditis
Myocarditis
Pleural effusion
Pneumonia

Severe

  • meningoencephalitis
  • delirium
  • fetal cardiac and renal failure
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13
Q

What is brill-zinsser disease?

A

A relapse of louse-borne typhus
- milder and less debilitating

Average is 10-20 yrs later

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14
Q

Where do you find the disease with brill-zinsser disease?

A

Lives in the

  • spinal marrow
  • lymphoid
  • adipose tissue

After the primary infection

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15
Q

Maurine typhus is aka?

A

Endemic or flea-borne

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16
Q

Maurine typhus transmission?

A

Rat to rat (via fleas) transmission of rickettsia typhi

Humans can catch it from the flea feces

17
Q

Maurine typhus is common in?

A

Large cities

  • Costal regions
  • California
  • texas
18
Q

Maurine typhus s/s?

A

Like a lighter louse borne typhys (rarely fatal)

  • mild and sorter course
  • lower fever
  • less severe HA
  • less rash
19
Q

Biggest differential of maurine typhus?

A

Brill-zinsser disease

  • they kind of look the same
20
Q

RMSF?

A

Rocky mountain spotted fever

Ticks (wood and dog) spread rickettsia rickettsii

  • seen everywhere in US
  • not just the rockies
21
Q

Mortality for RMSF?

A

Antibiotics have gotten this one under control
- usually only seen in delayed diagnosis and tx

Mostly its kids that die

22
Q

Endemic areas of RMSF?

A

South atlantic
Midwest
West south-central
US mexico border

So alaska is the place for avoiding it

23
Q

RMSF S/S

A
Gi symptoms
Skin necrosis
Cardiac 
- arrhythmias
- CHF
Atlectiasis
Renal disease
- papilledema
- retinal artery occlusion 
Enlarged liver/spleen
24
Q

Cardinal signs of RMSF?

A
Fever - 104-105.8
HA - persistent, intense, intractable
Rash - peripherally, wrist, palms, soles
Confusion - meningoencephalitis and coma
Myalgia - thigh or calf tenderness
25
Labs for RMSF?
CBC/Chem - thrombocytopeina - hyponatremia Skin biopsy Serologic PCR IFA testing
26
Q fever is cause by?
Coxiella burnetii Its actually a proteobacteria
27
Q fever causes?
Macrophages in lungs Vegetations on heart valves Granulomatous changes - reticuloendothelial organs
28
Q fever is common in?
Slaughterhouses Research facilities Livestock handling plants Military
29
Q fever transmission?
Contact with animal fluids Inhalation of aerosolized bacteria Ingestion of infected secretions
30
Q fever s/s?
``` Fever Intractable HA Chills Myalgia Cough Chest pain Pneumonitis/pneumonia hepatosplenomegaly ```
31
Q fever rash?
NO RASH
32
Radiographic findings of Q fever?
Multiple segmental opacities Pleural effusion Lobar consolidation Linear atelectasis
33
Less diagnostic lab findings or rickettsial disease?
Non specific - leukopenia - thrombocytopenia - hyponatremia
34
Serology and PCR for rickettsial disease?
Serology - mainstay of diagnosis PCR - expensive
35
Mortality rates for rickettsial diseases?
RMSF - w/o therapy - 25% - w therapy - 4% Lose borne typhus - under 12 - uncommon - 60-70% older than 50 yrs Brill-zinsser disease and murine typhus - no significant sequelae Q fever - <1% mortality
36
Top 4 blood sucking parasites?
Flea Tick Mosquito IRS agent