Week 6: Rickettsial Diseases Flashcards
Rickettsial Diseases AKA
Doxycycline Deficiency States
Doxycycline is okay in? Not okay in
- Okay in children (NO evidence of staining teeth when used in short courses)
- NOT okay in pregnant women
Rickettsialpox pathogen
Rickettsia akari
Scrub typhus pathogen
Orientia tsutsugamushi
What are Rickettsial Diseases?
Group of genetically similar intracellular bacteria that are transmitted by arthropods such as (ticks, mites, fleas, lice) and cause human disease on 6 continents and the vector’s geographic distribution determines when and how the disease presents clinically
Rickettsial diseases are caused by?
A group of genetically similar intracellular bacteria
Rickettsial diseases are transmitted by?
Arthropods (Ticks, mites, fleas, lice)
Determining factor of clinical presentation of Rickettsial diseases
Vector’s distribution geographically determines when and how the Rickettsial diseases present clinically
Typical presentation of Rickettsial diseases
typically causes
- fevers
- headache
- rash
- eschar “tache noire”
Rickettsial diseases that can be fatal
- Rocky Mountain Spotted Fever
- Ehrlichiosis
- Epidemic typhus
- Rarely anaplasmosis can be fatal
More about Rickettsial diseases
Rickettsiae Taxonomy
Anaplasmaceae Taxonomy
Coxiellaceae Taxonomy
Question
Arachnida Taxonomy
- Hard ticks cause the majority of diseases
- Soft ticks DONT cause the majority of diseases
Mites cause
- Rickettsia akari (Rickettsial Pox)
- Orientia tsutsugamushi (Scrub typhus)
Fleas cause
Rickettsia typhi
Lice cause
Rickettsia prowazekii
Case & pictures
Case & physical exam
Case & Labs
Case & biopsy
Rickettsia Taxonomy
What are convalescent serologies?
Initially IgG serologies are negative (as expected) but it takes awhile for these to form, 1-4 weeks later should have seroconverted
This is why you Treat first & Diagnose later regarding Rickettsial diseases
Why do you treat Rickettsial diseases first and diagnose later
Convalescent serologies
Initially IgG serologies are negatve as expected but 1-4 weeks later patient will seroconvert and IgGs will be positive
Question
Spotted fever group of Rickettsiae
- Rickettsia rickettsi
- Rickettsia africae
- Rickettsia conori
- Rickettsia akari
- Rickettsia australis
- Rickettsia japonicum
African Tick Bite Fever Pathogen
Rickettsia africae
Rocky Mountain spotted fever pathogen
Rickettsia rickettsi
Mediterranean spotted fever or Boutonneusse fever pathogen
Rickettsia conori
Rickettsiapox pathogen
Rickettsia akari
Queensland tick typhus pathogen
Rickettsia australis
Japanese spotted fever pathogen
Rickettsia japonicum
Epidemic typhus pathogen
Rickettsia prowazekii
Murine or endemic typhus pathogen
Rickettsia typhii
Scrub typhus pathogen
Orientia tsustugamushi
What is African Tick Bite Fever?
A common cause of fever in a returned traveler
Work-up of African Tick Bite Fever
Treat first
diagnose later
Treatment of African Tick Bite Fever
Doxycycline
African Tick Bite Fever Clinical Manifestations
- Fever
- Headache
- Eschar
- Maculopapular rash
Mediterranean spotted fever AKA
Boutonneuse fever
Mediterranean spotted fever clinical manifestations
- Fever
- Single eschar
- regional adenopathy
- Maculopapular rash on extremities
Mediterranean spotted fever geographic distribution
- Mediterranean region
- Africa to India Subcontinent
Mediterranean spotted fever vector
Ticks
African Tick Bite Fever vector
Ticks
African Tick Bite Fever Geographic distribution
- Sub-saharan Africa
- Caribbean
Rickettsiapox vector
Mouse mites
Rickettsialpox geographic distribution
- North Africa
- Korea
- Balkans
Rickettsiapox clinical manifestations
- Fever
- Headache
- papule->vesicular rash
Rickettsiapox
Rocky Mountain Spotted Fever vector
Ticks