Lyme / Ehrlichia Flashcards

1
Q

Location of Lyme / Ehrlichia

A

•Mainly found in northeast coast, WI, and MN

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2
Q
Lyme Disease
Cause
Population
Season
Reservoir
A
  • Borrelia burgdorferi
  • Bimodal distribution: kids 5-14 and adults 55-70
  • Mainly spring / summer
  • Normally lives in mice / squirrels
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3
Q
Transmission of Lyme Disease
NE / midwest vector
Pacific US vector
Lifecycle
Tick feeding / timeline
A
  • NE and Midwest: blacklegged tick (aka deer tick) Ixodes scapularis
  • Pacific US: pacific black-legged tick Ixodes pacificus
  • Lifecycle (takes 2 years): eggs → larvae → nymphs → adults → eggs
  • Need a blood meal to progress b/w each meal
  • Larvae usually acquire B burgdorferi from birds or mice. Infected for life.
  • Nymphs are the most likely to transmit disease to humans
  • Tick takes up blood and spits up excess water back into you, which transmits the bacteria. Also poops on you, which also may get rubbed in.
  • Tick’s saliva has anticoagulant and anti-inflammatory components to allow for continued feeding.
  • Tick usually needs to be attached for 36-72 hrs for transmission to occur
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4
Q

Lyme AB prophylaxis criteria (4)

A

Need to meet all 4 criteria to use doxycycline:
•Attached tick can be identified as nymph or adult I scapularis and has been present > 36h
•Within 72h of removal
•Local tick infection rate > 20%
•No contraindications

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5
Q
Stage 1 Lyme
Timeline
Sxs (local and systemic)
What does high fever suggest?
Diagnosis
A
  • Early localized infection (usually 7-14 days)
  • Sxs: Erythema migrans in 75% of pxs. Slowly expands outward. Center may become eccymotic / necrotic. Common on thigh, butt, groin, and axilla.
  • Systemic sxs in 80% of people: mild fever, chills, malaise, headache, joint / muscle pain.
  • High fever suggests coinfection w/ babesiosis
  • Diagnosis – clinical features + exposure risk. Abs are not positive yet.
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6
Q

Stage 2 Lyme
Timeline
Sxs (7)

A
  • Early disseminated (days / weeks after bite)
  • Multiple erythema migrans lesions
  • Migratory pain / joint pain (60%)
  • Neuro – Lyme meningitis (aseptic), facial nerve paralysis, radicular neuropathy (15%)
  • Lyme Carditis
  • Ocular, including ptosis
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7
Q

What 2 things should you suspect w/ Bell’s Palsy?

A

Bell’s Palsy: look for herpes and look for Lyme

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8
Q
Lyme meningitis
What stage?
Labs
Diagnosis
Sxs (5)
Treatment
A
  • Stage 2
  • Lymphocytic pleocytosis (100 cells), normal glucose, high protein
  • Lyme specific Ab is present in CSF
  • Headache, neck stiffness / pain, CN VII palsy, irritability, sleep probs
  • Tx w/ ceftriaxone b/c it penetrates the CNS well
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9
Q
Lyme carditis
What stage?
Clinical manifestations (3)
How long does it last?
Treatment
A
  • Stage 2
  • Fluctuating degress of AV block (8%). May use temporary pacemaker. Risk of myocarditis.
  • Fatigue / lightheadedness
  • Usually lasts days – 6 weeks
  • Tx w/ ceftriaxone in hospital and then oral therapy at home
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10
Q

Stage 3 Lyme
Timeline
Sxs (6)

A
  • Late disseminated (months after bite)
  • Lyme Arthritis – Intermittent or chronic attacks of large joint arthritis. Knee is most common. Inflammation.
  • Encephalopathy – cognition, sleep, personality
  • Polyradiculopathy, spastic paresis, ataxia
  • Fatigue
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11
Q

Lyme arthritis
What stage?
Diagnosis
Treatment

A
  • Stage 3
  • Lyme PCR of synovial fluid can help diagnose
  • Tx – oral AB’s. Ceftriaxone if recurrent. If persistent despite AB’s, consider an autoimmune disorder
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12
Q

Post-Lyme Disease Syndrome (aka Chronic Lyme Disease)
Timeline
Sxs (4)
Treatment

A
  • Unexplained sxs > 6 months after AB’s
  • Fatigue, myalgias, arthralgias w/o arthritis, cognition / memory problems
  • No benefit from prolonged AB use
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13
Q

2 step testing for Lyme

A

ELISA then Westernblot if ELISA was positive

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14
Q

General treatment for Lyme
Oral DOC / alternatives
IV drug / uses

A

•Oral: doxycycline is DOC. Contraindicated during pregnancy, lactation, or kids

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15
Q

Causes and general characteristics of Ehrlichiosis

Location in body

A

Anaplasma and Ehrlichia are small gram neg obligate intracellular bacteria w/ a tropism for WBCs. Common in bone marrow and RE system.

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16
Q
Human granulocytic anaplasmosis (HGA)
Cause / cell distribution
Vector
Animal reservoir
Histologic finding
A
  • Anaplasma phagocytophilum. Found in granulocytes.
  • Vector: I scapularis / pacificus (same ticks as Lyme, so distribution / risks are the same)
  • Animal reservoir is white tailed deer
  • Histo: Morulae are seen in 20-80% of pxs. These are cytoplasmic vacuoles where bacteria replicate.
17
Q
Human monocytotrophic ehrlichiosis (HME)
Cause / cell distribution
Vector / location
Animal reservoir
Comparison to HGA (human granulocytic anaplasmosis)
A
  • Ehrlichia chaffeensis. Found in monocytes.
  • Vector: Lone star tick. Mainly found in south central / SE US
  • Animal reservoir is white tailed deer
  • Comparison: causes more CNS disease and has higher mortality rate than HGA
18
Q
Sxs of ehrlichiosis
100% (4)
Less than 50% (4)
Others
Severe cases
A
  • Fever, headache, myalgias, malaise (100%)

* NVD, arthralgias, cough, confusion (

19
Q

Labs for erhlichiosis (5)

A
  • High ALT and AST (by day 1)
  • Low platelets (by days 1-3)
  • Low WBC/lymphopenia (by day 3)
  • Anemia (slow decline over day 7-14)
  • High creatinine (24-70%)
20
Q

Diagnosing ehrlichiosis (4)

A

Sxs, labs, blood smear w/ morulae (don’t hang your hat on it), PCR (takes weeks)

21
Q

Treating ehrlichiosis

A

Tx w/ doxycycline immediately. Do not wait for confirmed diagnosis. Rapid response aids in diagnosis. Hematologic problems improve after 2-5 days. Transaminases take 2-3 weeks to normalize.