Rickettsial Diseases Flashcards
Rickettsia Size? Gram? Movement? Shape? What are the similar to?
Small Gram-negative Non-motile Rod-to-coccoid-shaped bacterium Similar to Chlamydia
Rickettsiae
Pathology?
- -Obligate intracellular bacterial parasites (steal ATP)
- -They are unable to produce sufficient energy to replicate extracellularly
Rickettsia Transmitted how?
Where do they grow?
Human infection results from what? 2
How do they travel thrpughut the body and what are they specifically infecting?
Require an arthropod vector (except for Q fever)
In arthropods (insects), rickettsiae grow in the gut lining, often without harming the host.
Human infection results from either an
- arthropod bite or
- contamination with its feces
Circulate widely in the bloodstream (bacteremia)
Infecting endothelium of the blood vessel walls.
Pathophysiology of Rickettsial disease:
Rickettsia has a tropism for ?
WHy do you get damage in the endothelial lining?
Damage to the vessels of the skin results in?
Most Rickettsia cause what?
4
endothelial cells that line blood vessels
Inflammation from the infection of the endithelial
cells
the characteristic rash
- rashes,
- high fevers, and
- bad headaches,
- arthralgia,
What kind of rashes would you see in Rickettsia?
2
Vasculitis
Petechiae, purpura
How is the diagnoses made for Rickettsia?
Confirmation of your clinical diagnosis will be based on?
HISTORY OF INSECT BITE
measuring immunological titers to the infecting organism, and this may take weeks to develop
Health care providers MUST
know what about Rickettsia epidemiology?
2
- Know what types of insects reside in your community
2. What types of ARTHROPOD-borne diseases have been reported in your community
Rocky Mountain spotted fever: Pathogen? Geography? Insect/Vector? Other carrier?
Rickettsia rickettsii
Western Hemisphere United States (especially mid-Atlantic coast)
Tick
Rodents, dogs
RMSF onset of symtpoms?
4
When will the rash appear?
Describe the progression of the rash? 2
Acute onset of nonspecific symptoms, e.g.,
- Fever,
- severe headache,
- myalgias, and
- prostration.
Rash appears 2–6 days later,
- Macules that frequently progress to petechiae.
- The rash usually appears first on the hands and feet and then moves inward to the trunk
Work up for RMSF?
4
- CBC
- Chemistry panel
- May need spinal tap to study CSF and (rule out meningicoccus)
- blood cultures (rule out)
In your differential diagnosis what might the RMSF rash be confused with?
4
- measles,
- typhoid,
- ehrlichiosis, or most importantly
- meningococcemia.
Delay in RSMF treatment can lead to what?
severe disease and fatal outcome
What will you see on the CBC and chem panel for RMSF?
3
- aminotransferases (liver enzymes)- hyper bilirubin
- thrombocytopenia
- hyponatremia
What will you find in the CSF for RMSF? 3
Low glucose
high whote count
could lead to DIC
RMSF is susceptible to what kind of antibiotics?
Treatment length?
Susceptible to tetracycline-class antibiotics Doxycycline is considered the therapy of choice in nearly all clinical situations.
at least 3 days after the fever subsides and until evidence of clinical improvement is noted, which is typically for a minimum total course of 5–7 days.
What types of ticks will spread RMSF?
2
Dog ticks
Deer ticks
Epidemic Louse-borne typhus is caused by what?
This is a parasite of the body louse
Rickettsia prowazekii
Symptoms and Signs of Epidemic Louse-Borne Typhus
Prodromal symtpoms?
Incubation period?
Describe the onset (timing and symptoms of the acute illness stage)?
4
Prodromal 1. malaise, 2. cough, 3. HA, 4. arthralgias and 5. CP during incubation period of 10-14 days
Abrupt onset of
- chills, high fever, and
- flu-like symptoms progressing to
- delirium and
- stupor