Infectious disease Flashcards

(125 cards)

1
Q

suspected case

A
  • epidemiological exposure

- 2+ sx

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2
Q

probable case

A
  • relevant epidemiological exposure
  • no disease sx
  • positive IgM
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3
Q

confirmed case

A
  • viral RNA or antigen detected
  • IgM antibody
  • “tested positive for virus”
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4
Q

what causes zika

A
  • flavivirus

- single strand RNA virus

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5
Q

how is zika transmitted

A
  • mosquitoes
  • aedes aegypti and aedes albopictus strands
  • day and twilight feeders
  • breed in standing water
  • can be transmitted sexually, maternal-fetal
  • less frequently transmitted through blood transfusions, organ transplant, lab exposure
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6
Q

where did zika originate

A

uganda in rheusus monkeys

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7
Q

where are the more recent zika outbreaks

A
  • yap island- 2007
  • french polyesia- 2013-14
  • chile easter island - 2014
  • brazil- 2015
  • current- americas, caribbean, pacific islands, sub-saharan africa, asia
  • pregnant women/ attempting avoid travel below 6500 feet
  • cases in US related to travel
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8
Q

what fluids is zika detected in

A
  • blood
  • semen
  • saliva
  • female GU secretions
  • amniotic fluid
  • breast milk
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9
Q

clinical manifestations of zika

A
  • only in 20% of pts
  • mild in those with sx
  • low grade fever
  • pruritic rash
  • arthralgia - small joints
  • conjunctivitis
  • microcephaly in pregnant females
  • dx if 2+ sx
  • immunity after infection
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10
Q

what is the incubation period for zika

A
  • 2-14 days

- resolves in 2-7 days

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11
Q

less common sx of zika

A
  • HA
  • retro-orbital pain
  • myalgia
  • n/d
  • abd pain
  • mucus membrane ulceration
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12
Q

complications of zika

A
  • fetal loss
  • microcephaly
  • guillian barre syndrome
  • brain ischemia
  • myelitis
  • meningoencephalitis
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13
Q

diagnosis of zika

A
  • serum virus if sx onset < 14 days

- serum IgM if sx onset > 14 days

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14
Q

management of zika

A
  • supportive- rest, hydrate, APAP
  • NAIDS avoided until r/o dengue
  • ASA avoided in kids- Reye
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15
Q

prevention of zika

A
  • no vaccine
  • limit travel to certain areas
  • remove standing water
  • mosquito repellent
  • long sleeves/pants
  • environmental control
  • protected intercourse
  • must report zika cases to CDC
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16
Q

what causes chikungunya

A
  • alphavirus

- single strand RNA

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17
Q

where is chikungunya found

A
  • endemic to west africa
  • asia
  • europe
  • islands in indian and pacific oceans
  • americas
  • during rainy seasons
  • outbreaks have high attack rates
  • all US cases d/t travel
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18
Q

how is chikungunya spread

A
  • mosquitos
  • aedes aegypti and aedes albopictus
  • day feeder mosquitos
  • vertical transmission, blood donation, and organ transplant rare causes of transmission
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19
Q

clinical manifestations of chikungunya

A
  • abrupt fever (high grade) and malaise
  • polyarthralgia 2-5 days after fever in smaller joints bilaterally
  • pain is intense and disabling
  • maculopapular rash +/- pruritis
  • nonspecific lab changes
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20
Q

what is the incubation period of chikungunya

A
  • 3-7 days
  • acute phase lasts 7-10 days
  • majority of pts show sx
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21
Q

complications of chikungunya

A
  • death in pts >65 with comorbidities
  • persistent debilitating and immobilizing arthritis
  • resp, renal, and CV failure
  • can be persistent and relapsing up to 3 years
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22
Q

diagnosis of chikungunya

A
  • virus detected 1-7 days
  • antibodies detected > 8 days
  • IgM present after 5 days onset, persists for 3 mo
  • IgG present after 2 weeks, persists for years
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23
Q

management of chikungunya

A
  • supportive
  • NSAIDS
  • steroids, methotrexate, immune modulating agents for severe arthritis
  • no vaccine
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24
Q

prevention of chikungunya

A
  • minimize mosquito exposure
  • repellants
  • bed nets
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25
what causes dengue virus
- flavivirus - single strand RNA virus - four types DENV 1-4 with 46 strains
26
how is dengue spread
- mosquito - aedes aegypti and aedes albopictus - maternal- fetal transmission - leading cause of death in tropics and subtropics - death most often in kids
27
current dengue classifications
- dengue without warning sign - dengue with warning signs - severe dengue
28
where is dengue found
- rio de janeiro - bolivia - argenita - brazil - peru - paraguay - mexico
29
dengue without warning signs symptoms
- n/v - rash - HA - eye pain - muscle ache, joint pain - leukopenia - positive tourniquet test
30
dengue with warning signs sx
- abd pain - persistent vomitting - fluid accumulation - mucosal bleeding - lethargy or restlessness - hepatosplenomegaly - increased HCT and decreased platelet
31
severe dengue sx
- plasma leakage -> shock and fluid accumulation - respiratory distress - severe bleeding - severe organ failure - impaired consciousness
32
phases of dengue infection
- febrile - critical - convalescent
33
febrile dengue phase
- high grade fever - HA - rash - vomiting - myalgia - arthralgia - 3-7 days long - conjunctival injection - pharyngeal erythema - hepatomegaly - facial puffiness - petichiae - recover without complications
34
critical dengue phase
- systemic vascular leak syndrome - plasma leak - bleeding - shock - organ failure - days 3-7 and lasts 34-48 hours - mod- severe thrombocytopenia
35
convalescent dengue phase
- plasma leak and hemorrhage resolve - vital signs stabilize - usually lasts 2-4 days - rash may appear - profound fatigue, can take weeks to recover
36
diagnosis of dengue
- viral antigen in first week | - IgM as early as four days after onset
37
management of dengue
- supportive - APAP for fever - no NSAIDs bc of bleed risk - bleed management with blood replacement - volume replacement - shock tx
38
dengue prevention
- mosquito control - vaccination- only for seropos or hx of dengue - limit travel - improve community participation
39
ebola virus cause
- filoviridae - single strand RNA virus - resembles rabies, measles, mumps - has 5 species
40
how is ebola spread
- direct contact with infected body fluids
41
what are the ebola species
- zaire - sudan - tai forest (ivory coast) - bundibugyo - reston- only animal reservoir
42
where is ebola found
- sub-saharan africa - guinea - liberia - sierra leone - nigeria - senegal - mali
43
how is ebola spread
- contact with meat or body fluids of infected animals/ humans - virus can spread even after human/animal dies - lives on surfaces for hours- days - survives forever in immunologically privileged sites
44
what is the most infectious body fluid associated with ebola
- vomit - feces - blood - less infectious in early stages
45
who is at the greatest risk of ebola
- medical provider | - prep body for burial
46
ebola clinical symptoms
- fever, chills, malaise (d 1-3) - rash - n/v/d abd pain (d 3-10) - shock (day 7-12) - hemorrhage not often seen - convalescence up to two years- arthralgia, weakness, fatigue, insomnia
47
when do ebola pts start to get better if they survive
during the second week
48
lab findings for ebola
- leukopenia - thrombocytopenia - hematocrit increased or decreased - increased ALT and AST - coag abnormalities - renal abnormalities - electrolyte abnormalities
49
diagnosis of ebola
- ID pt risk - viral RNA in serum - ReEbov available for rapid dx (15 min)
50
ebola management
- supportive care - fluid/ electrolytes - anti-emetics - antipyretic - blood products - TPN - antivirals - compassionate use meds
51
prognostic factors for ebola
- age- younger has less mortality - gender- slightly higher mortality in males - GI- higher rate of mortality with diarrhea - viral load
52
ebola prevention
- strict infection control - proper use of personal protective equipment - communication btwn government and health care works - no vaccine - considered cat A bioterror agent
53
what makes up the sepsis continuum
infection -> bacteremia -> . sepsis -> septic shock -> MODS -> death
54
what is the most common cause of bateremia?
- staph aureus | - in community acquired and hospital acquired
55
what is the most common cause of bacteremia d/t skin and soft tissue infections
stroup a streptococcus
56
what is a common cause of bacteremia in immuncompromised
pseudomonas
57
seeding for bacteremia
- respiratory tract - UTI - abdominal infection - ENT - instrumentation i.e. catheter - surgery - prosthesis
58
clinical signs of bacteremia
- hypotension - tachycardia - fever - chills - malaise - SIRS possible
59
treatment for bacteremia
- empiric PO abx (staph and strep coverage)
60
sepsis
- life threatening organ dysfunction and infection | - dysregulated host response to infection
61
septic shock
sepsis with circulatory cellular and metabolic abnormalities
62
epidemiology of sepsis
- higher in AA males - greatest during winter - >65 is most cases - GP bacteria
63
SIRS diagnosis
- two or more of the following: - temp >38 C or < 36 C - HR > 90 - RR > 20 or PaCO2 <32 mmHg - WBC >12,000, <4,000 cells, or >10% immature forms
64
organ dysfunction assessment in sepsis
- GCS score - BP - ventilator support - renal function - liver function - platelets
65
risk factors for sepsis
- ICU admission - bacteremia - advanced age - immunosuppression - diabetes and cancer - community acquired pneumonia - previous hospitalization
66
septic shock clinical manifestations
- vasodilatory or distributory shock - require vasopressors - cool skin - cyanosis - oligouria - altered mentation - elevated lactate
67
multiorgan dysfunction syndrome (MODS)
- progressive organ dysfunction - severe end of severe illness - primary or secondary - no universally accepted criteria for dx
68
how is lyme disease transmitted?
- tick bite | - mainly deer tick aka black legged ticks (l. scapularis)
69
what causes lyme disease?
- borrelia burgdorferi | - spirochete
70
in what stage of life are most ticks in when they transmit lyme disease?
- nymph stage | - adults are larger so are more easily seen/ removed
71
risk factors for lyme disase
- outdoor occupation - recreational activities in wooded area - live in an endemic area like new england
72
when do deer ticks transmit lyme disease?
- when feeding (look engorged) - if tick is easily removed or walking on surface it cannot transmit disease - if attached for > 72 hours likely to transmit disease
73
what are the three phases of lyme disease
- early localized disease - early disseminated disease - late disease
74
clinical manifestations of early localized lyme disease
- erythema migrans*** - EM usually appears 7-14 days after bite - nonspecific viral sx - absence of rash means lyme is likely NOT your dx
75
common characteristics of erythema migrans
- painless - erythematous - circular - large diameter - central clearing may develop
76
symptoms of early disseminated lyme disease
- neurologic or cardiac involvement - occurs weeks to several months after bite - multiple EM lesions means disease is disseminated - uni/bilateral CN palsies (facial common)
77
symptoms of late lyme disease
- much less common - months to years after initial infection - usually arthritis in more than one joint (knees common) - neurologic subtleties
78
diagnosis of early lyme disease
- clinical dx - EM and/or viral symtpoms with hx of exposure is diagnostic - NO serology
79
diagnosis of early disseminated or late lyme disease
- hx and PE | - serologic testing as adjunct
80
when do you perform serology testing on a suspected lyme disease case?
``` - recent exposure to endemic area AND - risk factor for exposure AND - sx consistent with early disseminated or late disease ```
81
who should not get serology testing for lyme disease
- pts with EM rash | - screening of asymptomatic pts living in endemic areas
82
what serological tests are used for lyme disease
- ELISA then western blot
83
when do antibodies for lyme appear
- IgM- 1-2 weeks after infection - IgG- 2-6 weeks after infection - remain elevated even after treatment and resolution of sx for years - routine f/u serologic testing NOT recommended
84
what is the DOC for lyme disease?
- doxycycline - 100 mg orally twice daily X21 days - ** cannot be given to kids <8 or pregnant/ lactating women
85
what are the second line agents for treating lyme disease?
- amoxicillin 500 mg orally 3 times daily X21 days | - cefuroxime 500 mg orally twice daily X 21 days
86
what is the treatment for early disseminated lyme disease?
- IV antibiotics X 21-28 days - ceftriaxone - cefotazime - penicillin - caveat- if pt has facial palsy can treat with PO doxyxycline 100 mg twice daily
87
treatment for late lyme disease
- oral doxycycline or amoxicillin for 1 month | - usually to treat arthritis
88
can you be infected with lyme more than once?
yes
89
what is the prophylactic dose for lyme disease?
- doxycycline 200 mg orally as single dose (so take two pills once)
90
who should be treated prophylactically for lyme?
- tick ID as deer tick - tick was attached > 36 hrs - must start within 72 hours of tick removal - high rate of local infection - doxycycline not C/I
91
what causes rocky mountain spotted fever (RMSF)?
- r. rickettsi | - GN bacteria
92
what is the main issue with RMSF
- bacteria causes increased vascular permeability | - clinical response varies from pt to pt
93
who is most likely to die from RMSF?
- kids < 4 | - adults > 60
94
how is RMSF transmitted?
- tick bite - dock tick and rocky mountain wood tick - bacteria released 6-10 hours after bite
95
symptoms of RMSF
- usually start 2-14 days after bite - nonspecific viral sx - hallmark rash- blanching erythematous rash with macules that become petechial - rash usually begings on ankles and wrists -> trunk - rash seen on palms and soles
96
diagnosis of RMSF
- clinical diagnosis - serologic testing for confirmation - skin biopsy before or within 12 hours of abx - empiric therapy should be started within 5 days of sx onset
97
what is the DOC for RMSF?
- doxycycline
98
what causes babesiosis
- babesia protozoa
99
how is babesiosis transmitted
- tick bite
100
what is the main concern with babesiosis
- causes RBC lysis | - sx vary but can be fatal
101
clinical manifestations of babesiosis
- dev within 1-6 weeks of tick bite - associated with RBC lysis - fever, malaise, weakness - splenomegaly and hepatomegaly
102
who is most at risk for a severe course of babesiosis
- asplenism | - immunocompromised
103
what are complications associated with babesiosis?
- DIC - ARDS - CHF - renal failure
104
diagnosis of babesiosis
- blood smear - PCR - serology for acute infection (should not be sole diagnostic tool)
105
what is the DOC for babesiosis?
- atovaquone plus azithromycin | - 7-10 days of treatment
106
what causes rabies?
- rhabdoviridiae virus | - part of neuotropic viruses
107
what determines susceptibility to rabies
- bite location - virus varient - size of innoculation - degree of innervation at site of bite - host immunity and genetics
108
what disease has the highest case fatality of any infectious disease?
- rabies | - death primarily in developing countries
109
how is rabies transmitted?
- mainly exposure to saliva from animal bite
110
types of rabies
- prodrome- nonspecific viral sx - clinical rabies- either encephalitic or paralytic - once pt exhibits si/sx, often progresses to death
111
encephalitic rabies
- most common - death d/t respiratory and vascular collapse - hydrophobia and aerophobia - hyperactivity of facial, back and neck muscles - autonomic instability - agitation and combativeness
112
paralytic rabies
- ascending paralysis - starts in affected limb then spreads - little CNS involvement until later in course - death d/t respiratory muscles failure
113
diagnosis of rabies
- lab testing of several specimen - staining of skin biopsies - virus can be obtained from saliva - anti-rabies Ab obtained from CSF - most cases dx postmortem
114
what occurs around the site of a rabies bite?
- paresthesias
115
rabies treatment
- mainly focused on prevention - palliative treatment - aggressive treatment in ICU
116
post exposure prophylaxis of rabies
- can seek guidance from local public health authorities about who needs PEP - should be considered in bat bites/ bat exposure - can give immunoglobulin as passive immunization and vaccine as active immunization
117
rabies and travel prophylaxis
- give to people who may be working around rabid animals - kids who will be living in endemic areas - people who will be in areas where dog rabies is common
118
pre-exposure prophylaxis
- give 3 doses of vaccine - booster may be needed if ongoing risk of rabies - serologic testing can confirm protective levels
119
how is malaria transmitted
- mosquito bites
120
who is most at risk for severe malaria infections?
- young children - pregnant women - travelers to endemic regions - older kids and adults can dev immunity after repeated infections
121
what causes malaria?
- parasites | - p. falciparum causes severe illness
122
symptoms of malaria
- cyclic fever*** - nonspecific sx - anemia
123
how is malaria diagnosed?
- giemsa stained blood smear | - rapid diagnositc tests available in endemic areas
124
who requires hospitalization d/t malaria?
- young kids - immunocompromised - no acquired immunity - pts with parasitemia but no sx
125
what is the DOC for malaria
- chloroquine | - other regimens available for chloroquine resistant strains