Tick Bourne Diseases and Malaria Flashcards
Ixodes tick. Disease and organism.
Borrelia burgdorferi
Lyme Disease
American dog tick. Disease and organism.
Rickettsia rickettsii
Rocky Mountain Spotted
Lone Star Tick. Disease and organism.
Ehrlichia chaffeensis
Human monocytotropic ehrlichiosis
Sole vector of borrelia burg. in the eastern US?
Blacklegged tick/Deer tick
Stage 1/3 of Lyme disease
Localized Rash (Erythema migrans)
Stage 2/3 of Lyme disease
Disseminated Multiple annular skin lesions Meningitis Cranial Neuritis Carditis Arthralgia
Stage 3/3 of Lyme disease
Persistent... Oligoarticular arthritis Encephalopathy Axonal Polyneuritis Acrodermatitis
What is acrodermatitis
Skin changes of hands and feet
Rickettsia riskkettsii causes ______ by its trophism for _______
Rocky Mountain Spotted Fever
Vascular Endothelial Cells
Incubation period for Rocky Mountain Spotted Fever?
1 week
How does Rocky Mountain Spotted Fever vasculitis (the basic pathology) happen?
Increased vascular permeability Edema, hypovolemia *Hyponatremia *Thrombocytopenia Rare DIC
Classic presentation of Rocky Mountain Spotted Fever
Fever+Rash+History of Tick Exposure
Headache
Malaise
Myalgia
Describe the rash in Rocky Mountain Spotted Fever
Fait macules –> petichiae –> purpura
Involvement of palms and soles
Non-blanching
Progression of Rocky Mountain Spotted Fever
Tick, Fever, Rash
SYmptoms of Rocky Mountain Spotted Fever?
Hypovolemia, hypotension Respiratory failure Cardia arrythmia CNS (confusion, lethargy, enceph) Acute Tubular Necrosis Shock
What are you looking for in Rocky Mountain Spotted Fever Lab Testing?
Thrombocytopenia (low platelets)
Hyponatremia (low sodium)
Azotemia (high BUN)
Important non CBC tests to run for Rocky Mountain Spotted Fever
Skin Biopsy Serologic testing (of IgM and G)
Three factors that tend to cause physicians to fail to treat Rocky Mountain Spotted Fever
Absence of a skin rash
Presentation within the first 3 days
Presentation between Aug 1 and April 30 (not commonly tick season)
Drug of choice for Rocky Mountain Spotted Fever treatment? If you’re pregnant?
Normal –> Doxycycline
Preggers –> Chloramphenicol
Way to identify a Lone Star Tick (Ehrlichiosis)
White spot on the back
Incubation period for Ehrlichiosis?
usually about 8 days
Symptoms of Ehrlichiosis
Fever
Headache
Myalgias
Lab findings in an Ehrlichiosis patient
Leukopenia
Thrombocytopenia
Elevated transaminases
Treatment for Ehrlichiosis?
Doxycycline
Vector for Malaria?
Anopheles freeborni mosquito
Causative agent of Malaria
Plasmodium species
Most severe disease for Malaria?
falciparum
Differential diagnosis for CN7 Palsy
Idiopathic (Bell’s Palsy)
HSV (Herpes Simplex Virus) – No rash
Herpes Zoster - Ramsay Hunt Syndrome (vesicles in the external auditory
Lyme Disease
Symptoms of Chronic Lyme Disease
Pain syndrome (arthralgias)
Chronic Fatigue
Neurocognitive Symptoms
Treatment for Lyme Disease
Doxycycline
Diagnosis of Lyme Disease
Serologic Testing - IgM and IgG
ELISA with Western Blot verification
PCR of joint fluid
Tick prevention methods
Examine self after exposure Insecticides with DEET Tuck pants in socks Pre-treat clothes with permethrin insectisides Insect Shield
Differential diagnosis for fever, petechial rash on pales and soles, potential tick exposure
Meningococcal Disease Tick Bourne Disease -- RMSF Enteroviral disease secondary syph Rubella Drug eruption Kawasaki Coxsackie virus
Empiric therapy for meningococcal disease and RMSF
Ceftriaxone and Doxycycline
Lyme Disease Symptoms may be indistinguishable from
Chronic Fatigue Syndrome, Fibromyalgia
Difference between original presenting symptoms listed for Rocky Mountain and Ehrlichia?
Nausea with Rocky Mountain
Difference between CBC findings in Rocky Mountain and Ehrlichia?
RMSF – hyponatremia,
Ehr – Leukopenia
Similarities in CBC findings for RMSF and Ehrl.
Thrombocytopenia
Elevated Transaminase Levels
Incubation periods for RMSF and Ehrl.
RMSF – 2-14 days
Ehrl. – 5-14 days
What part of the tick do you check to identify when it is engorged?
Scutum
You should probably go back to the powerpoint and peek at the photos of the ticks again.
Seems like a reasonable thing to do?
The less commonly killing forms of malaria
P. vivax
P. ovale
P. mararae
P. knowlesi
Talk through the Malaria life cycle
Bryan – actually make yourself do this
- Plasmodium sporozoites have trophism for hepatocytes
- Asexual reproduction in hepatocytes
- Release into bloodstream
- Hijacking of RBC, Degradation of hemoglobin, Formation of Ring forms
- Lyse RBC, release merozytes infect more RBC, or gametocytes to reinfect mosquitos (hemolytic anemia –> direct hyperbilirubinemia = Jaundice)
Additions to the life cycle for P vivax and P ovale
Can produce dormant hypnozoites in hepatocytes
Can reactivate in 3-12 months
Clinica features of malaria patient
FEVER
Exposure to an endemic area
Lack of prophylactic treatment
Headache, Fatigue, Myalgias, Abdominal Pain
Seizures suggest which form of malaria?
P. falciparum infection
Paroxysmal chills, Fever, Rigors suggest what form of malaria?
P vivax or ovale
Caused by hepatic sequestration and re-release
Physical findings in a malaria patient
Fever Hepatomegaly Icterus (Jaundice) Palpable SPleen Rarely a rash, if so think of other diagnoses
What can happen with P falciparum in the vasculature
Sequestration and Agglutination
Severe abnormalities associated with P falciparum patients
Cerebral malaria (seizures, encephalopathy, coma)
Hypoglycemia (poor prognostic sign, loss of hepatic gluconeogenesis)
Metabolic Acidosis (Lactic acidemia from hypoperfusion)
Noncardiogenic Pulmonary edema (ARDS)
Renal Impairment (ATN)
Hematologic Abnormalities (anemia)
Liver Dysfunction (Cholestasis, Hepatitis)
Diagnostic testing for malaria
Light microscopy of Giemsa-stained blood smear
Thick and Thin Blood Smears
Rapid diagnostic tests w/ antigen detection
Reason you need Thick AND Thin blood smears
Thick – Concentrated Parasites, Increased Sensitivity
Thin – Pathologists can eval for ring forms and estimate parasite load
CBC findings in Malaria
Normocytic, normochromic anemia
Increased Acute phase reactants (ESR, CRP)
Treatment for Non-Falciparum Malaria
Chloroquine (if sensitive in that region)
Treatment for Falciparum Malaria
If def chloroquine sensitive, chloroquine
If unsure, Arteminsin-based combinations
Malaria prevention methods
Mosquito tents
Insect repellants
Preventative treatment in travelers
Which malaria drugs do you not give pregnant women?
Atovaquone-proguanil
Doxy hydrate
Primaquine
Which malaria drug has CNS side effects
Mefloquine
Three commonly used malaria drugs mentioned
Malarone
Doxycycline
Chloroquine
Important Malarone details?
Easy to tolerate, short lead up/follow up
Generic and Inexpensive
Important Doxy details?
Was inexpensive (apparently less so now) Have to take for 4 weeks after you're back
Important chloroquine details?
Generic, Inexpensive, Easy to tolerate