21 - Rickettsial Disease Flashcards
What is a “rickettsia organism”?
A middle ground between bacteria and viruses
- obligate intracellular gram-neg coccobacilli
Gram stain for rickettsia?
Doesnt stain well with gram stain
RED if stained with giemsa stain
Transmission of rickettsial disease?
Usually arthropods to humans
- except Q fever
3 Subgroups of rickettsial disease?
- Spotted fever group
- rocky mountain spotted fever - Typhus group
- louse-borne typhus
- brill-zinsser disease
- maurine typhus - Other
- ehrlichiosis
- cat scratch disease
- trench fever
- scrub typhus
Pathophysiology of rickettsial disease?
Multiply’s in the endothelial cells
Focal area is the site of infection but it then Hits the blood stream
Organs that are effected by rickettsial disease
Can affect all organs but
Most readily fond in the skin and adrenals
Common sites
- CNS
- Heart
- Liver
Common tx for rickettsia?
Doxy
Louse borne typhus is caused by?
Rickettsia prowazekii
Spread by lice (pediculus humanus)
Epidemics of louse borne typhus are common in?
Europe
Asia
Africa
- associated with overcrowding
Louse borne typhus s/s?
Abrupt onset - 1-2 wks after exposure Fever HA Rash
Louse borne typhus rash?
Presents on days 4-7
TRUNK -> extremities
- opposite of RMSF
Spares the face, palms and soles
Macules -> maculopapules -> petechiae
Complications of louse borne typhus?
Gangrene Pericarditis Myocarditis Pleural effusion Pneumonia
Severe
- meningoencephalitis
- delirium
- fetal cardiac and renal failure
What is brill-zinsser disease?
A relapse of louse-borne typhus
- milder and less debilitating
Average is 10-20 yrs later
Where do you find the disease with brill-zinsser disease?
Lives in the
- spinal marrow
- lymphoid
- adipose tissue
After the primary infection
Maurine typhus is aka?
Endemic or flea-borne
Maurine typhus transmission?
Rat to rat (via fleas) transmission of rickettsia typhi
Humans can catch it from the flea feces
Maurine typhus is common in?
Large cities
- Costal regions
- California
- texas
Maurine typhus s/s?
Like a lighter louse borne typhys (rarely fatal)
- mild and sorter course
- lower fever
- less severe HA
- less rash
Biggest differential of maurine typhus?
Brill-zinsser disease
- they kind of look the same
RMSF?
Rocky mountain spotted fever
Ticks (wood and dog) spread rickettsia rickettsii
- seen everywhere in US
- not just the rockies
Mortality for RMSF?
Antibiotics have gotten this one under control
- usually only seen in delayed diagnosis and tx
Mostly its kids that die
Endemic areas of RMSF?
South atlantic
Midwest
West south-central
US mexico border
So alaska is the place for avoiding it
RMSF S/S
Gi symptoms Skin necrosis Cardiac - arrhythmias - CHF Atlectiasis Renal disease - papilledema - retinal artery occlusion Enlarged liver/spleen
Cardinal signs of RMSF?
Fever - 104-105.8 HA - persistent, intense, intractable Rash - peripherally, wrist, palms, soles Confusion - meningoencephalitis and coma Myalgia - thigh or calf tenderness