Exam 2: Master Deck Flashcards by Anthony Carli

What percent of people infected with TB become ill?

10%

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Inadequate tx of TB has what 2 effects worldwide?

patients remain infectious

2. drug resistance

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TB co-infection with HIV and improper therapy have allowed what to occur in TB?

abx resistance (MDR, XDR)

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What makes TB difficult to eradicate?

long term tx

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T/F? Humans are the only reservoir for TB.

True

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This is a cutaneous manifestation of TB that is common in healthcare workers who are exposed to TB in lab conditions…

prosector’s warts

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TB is transmitted via…

aerosol droplet nuclei

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TB has a bimodal age distribution that sees peaks in what two ages?

infants

2. older adults

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The spread of TB in the blood (hematogenous dissemination) can result in what serious complication for what populations?

meningitis

infants and immunocompromised

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What is a complication of older age that can lead to reactivation of a latent TB infection?

immune failure

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What are three factors that influence the probability of being infected with TB?

Crowded Conditions

Prolonged Exposure

Virulent strain

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Who is the vector for TB in infants?

caregivers

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What chronic disorder confers a 30% increase in risk of developing TB?

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What lifestyle factors contribute to increased risk for developing TB? (4)

long-term care
EtOH/IVDU
Malnutrition
low income housing

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What three medical disorders confer increased risk for TB?

DM
silicosis
immunosuppression

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What three species produce human tuberculosis?

m. tuberculosis
m. bovis
m. africanum

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Which species of TB?

consumption of unpasteurized milk
contact w/ infected animals
source of BCG vaccine

m. bovis

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Which species of TB?

west african countries
especially hits HIV
Spread by food
No animal reservoirs

M. africanum

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This bacteria has the following characteristics:

obligate aerobe
slender, curved bacillus
non-motile
intracellular growth

m. tuberculosis

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Where does m. tuberculosis like to grow?

alveolar macrophages

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M. Tuberculosis is heat sensitive, meaning it is killed by what?

pasteurization

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Zeihl-Neelsen or Kinyoun stains are used to identify which acid fast bacillus?

MTB

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What are the two layers in the MTB cell wall?

peptidoglycan, mycolic acid

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This portion of the MTB cell wall contains LCFA, which makes up 60% of the lipid content in the cell wall.

mycolic acid

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This structural feature of MTB cell wall prevents dehydration and resists hydrogen peroxide

mycolic acid

Does MTB have classic virulence factors or toxins?

What causes pathogenicity of MTB?

structural features

What three features of MTB cause sxs for patients?

mycolic acid, cord factor, LAM

This MTB structure is a mycoside... aka mycolic acid+disaccharide

cord factor

This MTB structure inhibits cell mediated immunity, scavenges reactive oxygen intermediates

LAM

What causes caseous lesions in patients infected with MTB?

granuloma formation

The following describes what clinical manifestation of MTB? - surrounded by macrophages, multi-nucleated giant cells, fibroblases, collagen fibers. - harbors viable MTB cells - Evident 2-6 weeks after infx

granuloma

What allows a granuloma to be seen on x-ray?

calcification and fibrotic tubercle formation

What stage of TB infection? insidious onset of sxs cough, weight loss, fatigue, fever, night sweats, CP caseous lesions with necrosis

reactivation/secondary tuberculosis

What is responsible for causing infection due to secondary TB?

erosion and discharge of TB

this results from lymphohematogenous spread of primary infection or a latent lesion with subsequent spread...

miliary tuberculosis

a _______ stain and _______ culture can be used to detect acid fast bacteria

sputum stain broth culture

The rapid blood test for TB is based on the release of ______

IFN-y

IFN-y is produced by what isolated cell line?

T cells

GenXpert tests for ______ and _______ resistance

MTB and rifampin resistance

What three factors need to be controlled in order to prevent TB outbreak?

1. correct dx 2. isolation 3. tx

_______ and ______ infection can give false positives on a TST...

BCG receptors and NTM infx

Prophylaxis for MTB can be given to exposed subjects. It is dependent on HIV status and requires which drug for how long?

RIF x 9 mo

What is a weakly gram-positive aerobic, acid fast bacillus common in the environment, water, soil and plants?

MAC

Are MAC fast or slow growing

slow

How is is MAC transmitted?

ingestion of contaminated food/water

What distinguishes MAC from TB regarding transmission?

no person-to-person transmission no isolation required

This is the leading cause of NTM infx in HIV pts, and is an opportunistic human pathogen

MAC

What two populations of immunocompetent patients can be at risk for MAC?

middle-aged/older males with hx of smoking elderly female non-smokers

Patchy or nodular apparance on X-Ray and Lady Windermere's syndrome are associate with MAC infx in what population?

elderly female non-smokers

Cavitary lesions resembling TB is associated with MAC infx in what population?

middle-aged/older male smokers

Disseminated disease with MAC infx occurs with multisystem organ involvement and immune collapse in what population?

AIDS

What therapeutics can be used for MAC prophylaxis in HIV positive patients?

HAART and abx

What are two essential components to diagnosing MAC?

Acid Fast microscopy/culture exclusion of fungi/tb

What does treatment for MAC look like for HIV positive and negative?

combination abx

When can tx stop for MAC in HIV negative patients?

negative sputum cultures x 1 year

When can prophylaxis for MAC stop in HIV positive patients?

CD4 > 100

When should prophylaxis be considered for MAC in HIV positive patients?

CD4 < 50

When can abx tx for MAC stop in HIV positive patients?

lifelong if continued immunocomplromised or 2 weeks then HAART

Measles is also called...

rubeola

This disease is one of the classic childhood exanthems and can be severe in malnourished/vitamin A deficiency

Measles

What is the incubation period for measles?

10-14 days

Where does measles replication occur in the body?

respiratory epithelium and lymph

Measles can disseminate from respiratory epithelium and lymph nodes to other tisseus via what cell type?

monocytes

What stage of measles? 1-12 days post-infx high fever Coryza, cough, conjunctiitis Koplik Spots

Prodromal stage

Koplik spots are pathognomonic for...

measles

When does the onset of the measles rash occur?

3-4 days after prodrome initiation

What stage of measles? - highest fever - rash spreading from ears, downward to rest of body

Rash phase

In the resolution phase, antibodys are produced which stop the viremia. The measles rash will fade in what order?

same order it appeared

What are three broad complications of measles?

PNA Diarrhea CNS involvement

What measles complication... - responsible for most measles deaths - risk if malnourished - can be result of bacterial superinfx

Pneumonia

Which measles complication? -high fatality rate (15%)

acute symptomatic encephalitis

What type of encephalitis is rare, but a dangerous CNS complication of measles?

subacute sclerosing panencephalitis

Who are the two known hosts for measles?

humans and monkeys

Does measles have a healthy carrier state?

Immunity to measles typically occurs by...

10 yo

Measles is rare in patients below the age of _____ and why?

6 mo due to maternal immunity

How is measles transmitted?

respiratory droplet

Measles dx is confirmed by what three diagnostics?

rash and koplik spots serology FA test of mucosal swab

Swab of the pharynx, nasal, and buccal mucosa show what, which aids in dx of measles?

multinucleated giant cells

Which vaccines are indicated for measles prevention in exposed, non-immune subjects?

MMR and immune globulin (BayGam)

Describe the vaccination schedule for MMR

15 mo | 4-6 yrs

Which MMR vaccine type does the US use, what makes it not-suitable for all patients?

MMR II, live attenuated

What percent of the population must be vaccinated to stop measles persistence?

95%

in 2015, the largest outbreak since eradication in 2000 occurred. how many cases

668

What infection? nicknamed "little red" mild exanthemous disease resembles measles children often escape infx

rubella (german measles)

Rubella requires _______ contact for infection

close and prolonged

This complication of rubella... - occurs via maternal infection in 1st trimester - may lead to placental/fetal infection

congenital rubella syndrome

What three organ systems are affected by congenital rubella syndrome?

cardiac, eye, hearing

Congenital Rubella Syndrome (CRS) can cause what two cardiac malformation?

pulmonary artery stenosis, PDA

What eye defects can occur due to Congenital Rubella Syndrome (CRS)?

glaucoma, cataracts

What ear manifestations can occur due to Congenital Rubella Syndrome (CRS)?

hearing loss

the risk of CRS is highest in the 1st trimester. What percentages are associated with the months of the 1st trimester?

1st month: 50% 2nd month: 30% 3rd month: 20%

What nearly eliminated congenital rubella syndrome in the united states?

vaccination

If a mother is exposed to rubella, what is the last line prophylaxis you can administer during the 1st trimester?

IVIG

The following are two unique properties of what pathogen? 1. invade and replicate in CNS 2. establish latent infx

HSV

Is there a vaccine for HSV?

After primary HSV infection resolves, it establishes a latency where via what type of transport?

CNS dorsal root ganglia retrograde transport

can latent HSV reactivate?

yes

A patient presents with: - shallow vesicles on an erythematous base - ballooning vesicles that crust over

HSV

How is HSV transmitted to children?

caregivers/close contacts

Does the presence of active humoral and cellular immunity prevent the reactivation of HSV?

The probability of HSV recurrence is greater in individuals who...

have more severe initial outbreaks

Asymptomatic shedding means that HSV can be transmitted when?

without current outbreak

what three ways is HSV spread?

vesicle fluid saliva secretions

Which HSV type? - occurs early in life - 90% oral - common - 90% seropositive

HSV-1

Which HSV type? - infx occurs later in life - 90% genital - correlated to sexual activity

HSV-2

HSV dx is accomplished by using...

direct sample of tissue

what two drugs are: - most prescribed HSV agent - Stops viral DNA replication by blocking viral thymidine kinase - can suppress HSV recrudesence

acyclovir, valacyclovir

A patient presents with the following, which is concerning for... - asymmetrical vesicular rash - fever, malaise, headache, neuralgia - pruritic leesions

varicella

The varicella virus infects through what tissues?

conjunctiva or respiratory mucosa

Where does varicella replicate in the 4-6 days after infection?

regional lymph nodes

Where does varicella replicate during secondary viremia (rash phase) 10-14 days after infection?

liver and spleen

Varicella peaks in what seasons?

winter-spring

90% of all varicella cases occur between years...

1-14

When is a patient most contagious with varicella?

1-2 days before lesions and 4-5 days after

prodromal sxs of varicella are absent in what age group?

younger children

What medication should be avoided with varicella infection and why?

aspirin, reyes syndrome

What two drugs can be given to treat chickenpox?

acyclovir VariZig

What vaccine is available for varicella?

varivax

Are chickenpox cases occurring in vaccinated children?

yes, often due to incomplete courses

What prevention therapy is available for high-risk peole exposed to varicella?

VariZig

infection of varicella can produce significant disease and damage, this is called

congenital/neonatal VZV

These lesions are painful, described as searing, burning, stabbing. Pain may precede the rash by days/weeks

Shingles

Varicella Zoster (shingles) presents in what pattern?

unilateral dermatomal distribution

What percent of shingles cases have involvement of ophthalmic branch of CN V?

10%

What is an absolute prerequisite for shingles infection?

varivax vaccination or hx of chickenpox

What vaccine for shingles is... - adjuvanted, recombinant - recommended for prior zostavax recipients - DOC

shingrix

What vaccine for shingles - pts over 50 yo - high potency VZV vaccination to boost immunity - same virus as varivax, but higher potency

zostavax

This disease... - called Roseola infantum, 6ths disease, or exanthem subitum - fever followed by rose-colored rash - prevalent and unrecognized until culture system was available

human herpes virus 6

this is one of the most regularly acquired viral infections of childhood. 30% of children 6mo-3yo have had this.

HHV-6

A patient presents with sustained fever of unknown origin for 2-5 days, but is otherwise well appearing

Roseola infantum (HHV-6)

What 2 methods of HHV-6 diagnosis are available?

Ab detection via EIA DNA sequence detection via PCR

Is treatment required for HHV-6?

This disease is called "Fifths Disease" or erythema infectiosum. it often appears in children with a "slapped cheek" rash

parvovirus B19

A patient presents with: Prodrome of mild fever, HA, malaise, myalgia, respiratory sxs +/- NV Post-prodromal skin rash with circumoral sparing which resolves in 1-2 weeks

parvovirus b19

the rash of parvovirus B19 commonly affects...

limbs and trunk

What connective tissue manifestations can be present with parvovirus B19?

arthralgia, arthritis

Parvovirus B19 has a worldwide distribution among school age children, and is epidemic in what seasons?

late winter and spring

What three things aid in Parvovirus B19 diagnosis?

facial rash anti B19 IgM epidemic outbreak

What tx can be given to relieve sxs of parvovirus B19?

NSAIDs

What tx for Parvovirus B19 can be given to anemic patients?

immunoglobulin

What two HPV types are correlated with cervical dysplasia and cancer?

HPV 16 and 18

What two types of HPV are associated with anogenital warts?

HPV 6 and 11

Gardasil 9 protects against which 5 types of HPV?

6, 11, 16, 18 and 5 others

For whom is gardisil vaccine indicated?

ages 9-45

Erysipelas, Impetigo, Folliculitis all infect what layer of the skin?

epidermis

Ecthyma, furunculosis, carbunculosis infect what layer of the skin?

dermis

Cellulitis infects what tissue layer?

superficial fascia

Necrotizing fascitis infects what tissue layer?

subcutaneous tissue

Myonecrosis infects what layer of tissue?

muscle

If the following factors are present, then a skin infection can be considered... - pre-existing wound - deeper tissue involvement - needs surgery - refractor/recurrent - associated with underlying dz

Complicated

Recurrent skin infection should raise concern for what

MRSA or underlying issues

If a foreign body is present in the skin, what happens to the infectious dose?

drops dramatically

This skin infection: - disease of sebaceous follicles - noninfectious folliculitis - teens/young adults - androgen trigger

acne vulgaris

The following are characteristics of what cause of acne vulgaris? - G+ - Anaerobic Rod - Normal Skin flora - colonize skin, sebaceous glands

propionibacterium acnes

When follicular contents rupture in the dermis, what is the infection now known as?

inflammatory acne vulgaris

folliculitis is usually caused by what two bacteria

staph. aureus pseudomonas aeruginosa

if folliculitis doesn't respond to topical tx, what should be done?

gram stain to r/o G- or MRSA

What causes hot-tub folliculitis?

pseudomonas aeruginosa

This pathogen which causes folliculitis has the following characteristics: - majority of abscess-type infx - G+ - Coagulase +

staph aureus

This pathogen which causes folliculitis has the following characteristics: G- rod opportunistic ubiquitous produces pyocyanin and pyoverdin

pseudomonas aeruginosa

carbuncles and furuncles are more common in what 4 populations?

obese immunocompromised DM elderly

What is the primary tx for furuncles?

incision and drainage

when should abx be considered for furuncles/carbuncles?

> 5mm don't resolve w/ drainage evidence of spread immunocompromised

Abx for carbuncles/furuncles must be able to cover what pathogen?

MRSA

A pt. has multiple carbuncle/furuncles, and has a fever. What aggressive therapy can be administered?

rifampin

What can prevent recurrence of furuncles?

chlorhexidine/isopropyl alcohol soap maintenance abx

impetigo is caused by what two agents?

staphylococci, streptococci

This is a deeper, ulcerative form of impetigo

ecthyma

What are the 2 types of impetigo?

non-bullous and bullous

What two agents can cause non-bullous impetigo?

staph aureus strep. pyogenes

this type of impetigo has the following characteristics: - MC in infants and younger children - specific strains of S. aureus only - bacterial colonized fluid-filled bullae formed

bullous

What causes the formation of bullae in bullous impetigo

exfoliative toxin

This is a severe form of impetigo characterized by a deep invasion of the dermis. hard crust that is deeper, thicker than impetigo

ecthyma

when should you consider cx of impetigo/ecthyma?

if no response to tx/topical abx

This is a skin disease characterized by the following: - acute, extensive epidermolysis - nicolsky positive - presence of sterile bullae - MC children < 6, infants especially

staphylococcal scalded skin syndrome (Ritter's Disease)

What causes the formation of bullae in ritter's disease?

staphylococcal toxin

What abx can be used for scalded skin syndrome?

penicillinase resistant penicillan

what should scalded skin syndrome be treated similarly to if extensive disease?

tx like burns

describe the mortality rate for scaled skin disease...

low, due to 2ry infx

Erysipelas or cellulitis? - superficial - caused by GAS - focal dermal lymphatic involvement - well demarcated border

erysipelas

What are two severe complications of erysipelas

septicemia, meningitis

What three populations are at risk for erysipelas?

young children, immunocompromised, older adults

what are the most common sites for erysipelas infx?

legs and face

what is the best treatment for erysipelas?

PO or IV abx for most-likely agent

Erysipelas or cellulitis? - unilateral infection, deeper dermis/subQ tissue - indistinct borders - localized vesicles, bullae or abscess - caused by staph aureus and s. pyogenes

cellulitis

What can help monitor the spread of cellulitis?

mark borders of rash

Where is cellulitis most common?

lower extremety

Cellulitis may result from infected skin breakage or endogenous seeding. This means that a ______ may not be evident

wound may not be evident

What are 3 complications from cellulitis

sepsis local gangrene necrotizing fasciitis

Cellulitis can be characterized by HEET... which stands for...

heat, erythema, edema, tenderness

What to things cause sxs in cellulitis?

bacterial toxin | inflammatory response

cellulitis infection is commonly of a ______ etiology

mixed

What drugs must be avoided in cellulitis for fear of myonecrosis pain masking?

NSAIDs

This common cellulitis pathogen is associated with... cat bites

pasteurella multocida

This common cellulitis pathogen is associated with... dog bite

capnocytphaga

This common cellulitis pathogen is associated with... fresh water injury

aeromonas hydrophilia

This common cellulitis pathogen is associated with... salt water injuries

vibrio vulnificus

This common cellulitis pathogen is associated with... previous trauma/surgery

acinetobacter baumannii

What is the carriage ratae of MRSA?

2% in general population

What genes confer resistance that cause MRSA?

MEC/MEC-A

A patient presents with a kin infx with the following features... - fluctuance - yellow/white center - central point - pus drainage

MRSA

What two tests can detect the presence mecA and help dx MRSA

PCR and latex agglutination assay

A patient presents with: - HEET sxs - Pain out of proportion to apparent issue - no true pus anywhere, think brown exudate - rapid progression - pink/purple bullae - red/purple patches-blue gray

necrotizing fasciitis

What helps dx necrotizing fasciitis?

tissue bx imaging

What differentiates necrotizing fasciitis from cellulitis?

failure to respond to abx

what is the tx for necrotizing fasciitis?

surgical debridement/amputation IV abx

Gas gangrene primarily infects muscle tissue and is called...

clostridial myonecrosis

What spore forming, G+, anaerobic bacillus accounts for 90% of gas gangrene cases?

clostridium perfringens type A

a patient presents with... rapid onset of pain bronze skin edema, tender, crepitant skin bullae

gas gangrene

what causes the crepitus skin in gas gangrene?

H2 gas production splitting tissue layers

A gram stain and biopsy in gas gangrene would show...

gram variable rods muscle necrosis

How do you treat gas gangrene?

IV abx hyperbaric oxygen surgery

A patient presents with a fever and sunburn-like whole body rash. began as soft-tissue inflammation at site of apparent infection

toxic shock syndromes

What two conditions often occur alongside toxic shock syndrome?

bacteremia necrotizing fasciitis

What toxin from staph aureus can cause sxs in toxic shock syndrome?

enterotoxin type b - superantigen

toxic shock syndrome can occur in what patient population

otherwise healthy, no pre-existing skin infx

the toxic shock syndrome superantigen causes what?

extensive immune response

What are the three important genera of dermatophytes?

microsporum trichopyton epidermophyton

______ is the infectious state of dermatophyte disease and can be visualized in 10% KOH prep

arthroconidium

What laboratory test allows early detection of dermatophyte infection?

dermatophyte test medium

What dermatophyte antigen is described by: - galactomannan peptide antigen - crude antigen of dermatophytes - CHO component causes immediate response - Peptide component causes delayed response

Trichopytin

This diagnostic for dermatophyte infection has the following characteristics: - uses a red color change to indicate positive - selective and differential based on CHO fermentation

dermatophyte test medium

What are the three classifications of dermatophytes?

zoophilic antrophophilic geophilic

Were do dermatophytes like to live on the body?

moist areas

dermatophyte infection is common worldwide, but most prevalent where?

tropics

arthrospores are fragment hyphal elements found where on the body?

hair, nails, outer skin

hair, nails, outer skin can exhibit infx by arthrospores and what other three types of fungal infx?

microconidia, macroconidia, sexual spores

This is an allergic dermal reaction to fungal antigens in areas devoid of the organism MC in tinea pedis

dermatophytid

These fungal species have the following characteristics... - not often fluorescent - pencil shaped macroconidia with thin walls PRODUCE: -spindle shaped hypae - microconidia - macroconidia

trichopyton

These fungal species have the following characteristics... MC cause of tinea capitis fluoresce under wood's lamp PRODUCE: - hyphae - microconidia - large, spindle shaped, multicellular, thick walled macroconidia

microsporum

MC causative agent of tinea capitis is...

M. canis

What is the most prevalent dermatophyte infection?

tinea pedis

How is tinea corporis and tinea cruris transmitted?

towels, clothing, linens

tinea unguinum is often mistaken for...

psoriasis

what works better at treating tinea unguium infection, topical or systemic antifungals?

systemic

tinea unguium causes...

onychomycosis

This is the most commonly encountered opportunistic mycosis worldwide

candidiasis

The following are common causes of... - absence of competing flora - introduction to abnormal site - pathologic change in microenvironment - inborn/acquired immune defect - use of broad spectrum abx

candidiasis

does candida albicans have virulence factors?

not many

is the candida germ tube or yeast cell more adhesive?

germ tube

Under direct microscopy, you notice large G+ cells showing yeast cells, pesudohyphae and true hyphae. What is this indicative of?

candida

On culture, the presence of what feature helps diagnose candida?

germ tubes

Tinea versicolor is caused by what?

malassezia furfur

This fungal species... - spaghetti and meatballs arrangement - has lipophilic growth factor - forms yeast like colonies

malassezia furfur

this fungal species... - extreme halotolerant - dimporphic, grows as yeast or mold - tropical disease - produces bron lesion due to fungus produced melanin

hortaea merneckii

This ectoparasitic infection: - burrowing mite - relative to ticks - small mite with short legs

sarcoptes scabiei

Does the male or female scabiei mite lay eggs under the skin?

male mite

The adult scabies mite develops _____ after hatching

2 weeks

how long does scabies pruritis/allergic response take to develop with first infection?

weeks

scabies reinfection can see symptoms how quickly?

< 24 hrs

What scabies disease? - 1 mo incubation - crusted, pruritic lesions - observed in HIV - lesions teeming with mites

crusted scabies

a patient presents with sxs similar to crusted (norwegian) scabies, but lesions are blood filled/red...

pediatric scabies

What is applied to the lesion in order to scrape off and capture scabies mites, mite parts, eggs, or feces?

mineral oil

does ivermectin kill scabies eggs?

What is the preferred tx for scabies?

5% permethrine

What causes pediculosis?

pediculus humanus

How long is the egg-to-egg cycle in pediculus humanus?

3 weeks

vagabond's disease is a result of pediculosis infection for ______ and manifests with ____

years long infestation darkened, thick skin

pediculus humanus causes sxs via...

bloodsucking bite irritation

What tx for pediculosis?

permethrin, OTC

Which ectoparasite? - 1-4 mm length, laterally compressed - blood parasite - inject allergic saliva during blood meal - short spikes on legs that allow host attachment

pulex irritans (flea)

Flea or scabies? - bites in groups of 3-4, linear - raised bumps, halo surrounding site - rash on different parts of body - non-contagious rash

flea

Flea or scabies? - pimple like rash - intense itch at nighttime - restricted to one body region due to slow crawl - appearance of tunnels

scabies

What tick species carries rickettsia rickettsii?

brown doc tick

This is a G-, obligate intracellular, pleomorphic pathogen responsible for RMSF

rickettsia rickettsii

sxs of RMSF appear how quickly?

2-14 days

the 1st rash in RMSF appears 2-5 days post-infection and looks like..

small, flat, non-pruritic macules

The 2nd rash in RMSF appears 6 days post infx and can be described as...

red-purple spotted petechial rash

development of a petechial rash in RMSF indicates...

severe, late infx

What is the gold standard for dx of RMSF and at what intervals?

indirect immunofluoresence 2 samples 2-4 weeks apart

in pregnant patients with mild RMSF, what can be used?

chloramphenicol

This genera causes african sleeping sickness, chagas and leishmaniasis...

trypanosomatids

what is the vector for Chagas (american trypanosomiasis)?

triatomine bug (kissing bug)

What parasitic protozoan is carried on the triatomine bug and responsible for chagas?

trypanosoma cruzi

What phase of the T. cruzi life cycle: - passed in feces at night - enter cells near inoculation site and differentiate to amastigotes

trypomastigotes

This stage of the T. cruzi life cycle sees replication by binarry fission, and differentiation to trypomastigotes to be released to circulation

amastigotes

What two signs are characteristic of acute chagas?

Chagoma romanas sign (swelling of eyelid)

Chronic chagas can see heart and intestinal complications. which is more common?

cardiac

Presence of trypomastigotes in blood smear indicate what phase of chagas?

acute

presence of amastigotes on biopsy indicates what phase of chagas?

chronic

What two lab tests are available for chagas?

serology | PCR

the antiparasitic drug Benzidazole is only available thru...

CDC

what type of cancer is linked to EBV infection?

burkitt's lymphoma

how long is the incubation period of EBV?

1-2 months

EBV is an infection of what lymphocytes?

B cells

Primary EBV viral replication occurs in the _____ and eventually reaches what tissue?

primary: oropharynx reaches lymph nodes

how long is the prodrome of flu-like sxs with EBV?

3-5 days

A patient presents with: - ST - symmetrical LAD - fever +/- hepatomegaly, increased LFTs, jaundice

EBV

Atypical lymphocytes called _____ appear in circulation with EBV infection.

downey cells

What cell type controls EBV infx, but also generates most sxs?

T cells

What is the peak incidence of EBV infx?

17-25

how long can EBV be found in saliva?

1 mo

the presence of ___ antibodies and patient age are keys to EBV dx...

heterophile Abs

What patient population may not have a strong heterophile Ab response to EBV, therefor making monospot inaccurate?

pre-teens

how can you confirm EBV infection?

Monospot Serology showing IgM anti capsid antigen and anti-VCA

CMV is similar to EBV, except it doesn't produce what?

heterophile antibodies

for whom is CMV infection most problematic?

immunocompromised and pregnancy

Can vaccinated people still get mumps?

yes

Lyme disease is caused by infection by...

borrelia burgdorferi

Which disease progresses through stages in a pattern similar to syphilis?

lyme disease

Which stage of lyme disease? - erythema migrans which fades within a month - flu-like sxs

acute localized (stage 1)

Which stage of lyme disease? - flu-like sxs - assymetric arthritis attacks - annular skin lesions - +/- hepatitis, meningitis, facial palsy - 2 weeks to months after infx

subacute disseminated (stage 2)

Which stage of lyme disease? - longer, persistant arthritis attacks - MSK manifestations - second-third year after infx

Chronic (stage 3)

what are the reservoirs for lyme disease

rodents, rats, mice, birds

Which disease is associated with forest edge locations (i.e. mouse habitat)

lyme disease

A substantial portion of human lyme infections are transmitted by...

nymphal stage ticks, deer tick or black legged tick

What serological testing sequence confirms lyme?

EIA, if positive, western blot

patients infected with lyme are testing positive by what week?

4th week

Syphilis, EBV, SLE, RA, oral spirochete infx can cause false positives for what disease?

lyme disease

Patients with symptomatic lyme disease can be treated with...

amoxicillin or doxy x 10-21 days

Is prophylactic abx for lyme typically done

10-20% of abx treated lyme patients have lingering pain and joint problems. This is called...

post-tx lyme disease syndrome

What is the main way to prevent lyme infection?

control and avoidance of vectors tick checks DEET

PrEP for lyme is now being done with...

monoclonal Ab vaccine

Redmeat allergy is associated with...

lone-star tick

Which hepatitis? - fecal oral route - not chronic

A/E

Which hepatitis? - blood/body fluids - percutaneous permucosal transmission - can be chronic

B/C/D

HCV is also called...

transfusion associated

Chronic hepatitis is only possible for which types?

B,C,D

type D hepatitis is only in patients with what active infx?

HBV

The subclinical, anticteric course of hepatitis can be recognized by...

seroconversion

Which course of hepatitis has a high fatality rate?

fulminant hepatitis

Which hepatitis causes infectious hepatitis?

HAV

HAV is diagnosed via what laboratory test?

Presence of IgM Ab via ELISA

What is the treatment for HAV?

supportive

Is vaccine available for HAV?

yes

What can be used for HAV PrEP?

immunoglobulin

What are three major prevention mechanisms for HAV?

handwashing avoid contaminated food education

This hepatitis: - infectious cause of 80% of primary hepatocellular carcinoma - common cause of chronic hepatitis

HBV

What is the infectious form of HBV?

Dane particle

What are three antigens present on the dane particle?

HBsAg (surface antigen) HBcAg (core antigen) HBeAg (surface antigen)

The presence of which HBV antigen is the best indication of an infectious patient?

HBeAg

What is the major reservoir of HBV?

chronic hepatitis patients

Who poses the greatest risk for perinatal congenital HBV infx?

HBeAg POS mother

Who are two populations that are at risk for HBV infection?

healthcare workers IVDU

Why do we vaccinate newborns for HBV?

90% of HBV infx in newborns become chronic

How long is the incubation period for HBV?

50-180 days

A patient presents with insidious onset of a self-limited infx: - fever - urticarial rash - semetrical arthralgia

HBV

What percent of HBV infx in adults become chronic?

5-10%

Which HBV antigens are secreted into the blood stream during infection? The presence of these without Abs to them indicates...

HBsAg, HBeAg presence w/o Abs = chronic state

What is the hallmark of initial ongoing HBV infection if present alongside HBsAg?

IgM anti-HBc + HBsAg

A patient was tested for HBV and has the following results. What does this indicate? -POS IgG anti-HBc

past infx

A patient was tested for HBV and has the following results. What does this indicate? - POS IgG anti-HBc - POS HBsAg

chronic infx

Detection of which antigen is the best indication of infectious HBV virus?

HBeAg

A patient was tested for HBV and has the following results. What does this indicate? POS HBeAg POS HBsAg

chronic infx

What test is available to detect HBV Surface antigen?

rapid hepatitis tests

How is HBV treated?

no specific cure, mostly self-limiting

How are chronic cases of HBV treated?

PEG-Interferon plus antivirals non curative tx

This type of hepatitis requires presence of HBV and is a viral parasite of another virus...

HDV

HDV can occur under what 2 conditions

1. HBV coinfection | 2. Superinfx with chronic HBV

Fluminant hepatitis is more likely with...

HDV

How is HDV diagnosed?

ELISA for delta antigen or Abs

Does the HBV vaccine also prevent HDV?

yes

How is HDV treated?

PEG-interferon

What is the hallmark of HCV?

chronic infx (70-85%)

Chornic HCV occurs despite the presence of what?

high anti-HCV

What is the most common cause of HCV?

idiopathic

What is used for screening for HCV?

enzyme immunoassay detectio of HCV Ab

Seroconversion occurs when after HCV infection?

24 weeks

Chronic state and acute phase viremic patients with HCV can escape Ab Enzyme Immonoassay screening. What can be used to confirm HCV?

direct assay for virus

What is a revolutionary and possible cure for HCV?

direct acting antivirals (protease or polymerase inhibiter)

In HBV/HCV coinfection, treatment of HCV with DAAs may cause...

activation of HBV

HCV tends to ____ HBV

suppress

What is making a new approach to liver transplant in hepatitis patients?

new generation drugs

What are the two leading causes of liver transplant for hepatitis?

cirrhosis and hepatocellular carcinoma

Transplant may be the only curative option for which hepatitis viruses?

HBV, HCV

Can an HCV positive patient donate their liver?

yes, due to new therapy

HIV often mimics which virus?

EBV

When is HIV most easily transmitted?

early stage, unaware of HIV status

AIDS is diagnosed when?

severe immune system damage CD4 < 200

The presence of the following indicate HIV or AIDS? ``` kaposi's sarcoma pneumocystitis PNA MAC infx CMV crypto Candidiasis ```

AIDS

What are the 4 HIV course classes?

fast (3 years to AIDS) intermediate ( 10 years to AIDS) Long-term slow progressors (> 10 years years to AIDS) elite controllers

Sequencing of HIV genome has revealed what?

entry of HIV to humans several times (early as 1950s)

What three cell types are commonly infected with HIV

T-helpers, monocytes, macrophages

What two receptors must be present on cells for HIV infection?

CD4 and chemokine co-receptor

What enzyme allows for integration of viral genome to host chromosome?

viral integrase

HIV mutates quickly, making what method of treatment manditory?

multi-drug/combo therapy

What is more common worldwide, HIV-1 or HIV-2?

HIV-1

Which HIV type? - slower progression - less easily transmitted - resistant to NNRTIs

HIV-2

What is responsible for clinical latency in HIV progression?

antibody production

HIV is diagnosed via what to Ab tests?

EIA + Western blot confirmation

Donated blood undergoes direct testing, what tests are used?

NAT

Donated blood is screened for what two substances?

antigen p24 or RNA genome

How many people are estimated to be infected with HIV in the US, but not know it?

280k

Is there a rapid test for HIV?

yes

What are the three main classes of HIV antivirals?

reverse transcriptase inhibitors protease inhibitors fusion penetration inhibitors

Combo of which two antiviral classes has made a huge difference in managing HIV?

reverse transcriptase inhibitors + protease inhibitors

viral load under ____ means it is suppressed, and viral load virtually undetectable..

< 50

viral load over ____ means HIV is reproducing

1000

How often should HIV patients have viral load testing done?

every 90 days

HIV has major impacts on which organ system?

CNS

Are patients in viral suppression contagious?

What are the 5 types of malaria?

``` vivax falciparum malariae ovale knowlesi ```

Which two types of malaria are most common?

vivax and falciparum

The malaria life cycle has two broad phases...what are they

mosquito phase and human phase

upon injection into humans, plasmodium ______ are transmitted

sporozoites

Sporozoites travel to what tissue for asexual division?

liver

sporozoite reproduction in the liver is known as the ______ cycle

schizogony

What type of life-forms are released during the schizogony cycle of plasmodia?

merozoites

what form of plasmodium is a vaccine target?

sporozoite

This phase of plasmodia can infect liver cells or RBCs, initiating the erythrocytic cycle

merozoites

Once merozoites enter the RBC, they differentiate to a uninucleate cell called a...

ring trophozoite

Mature trophozoites can become ______ trophozoites which are capable of reinfecting other cells

amoeboid trophozoite

When the single nucleus of a trophozoite divides, it can form a multinucleated cell called a

schizont

________ are multinucleated cells that produce erythrocytic merozoites

erythrocytic schizonts

When an RBC lyses, merozoites escape and what two reproductive cycles can occur?

schizogony or gametogony

Do plasmodia gametocytes cause RBC lysis?

What is the fate of gametocytes in RBC?

uptake during mosquito blood meal, sporozoite production, changes within mosquito, resistance

The release of what substance intensifies symptoms of malaria?

tumor necrosis factor

fever and chills in malaria correspond to the release of what substance after RBC lysis?

pyrogen

Does malaria have local or systemic effects?

systemic

What is the only malaria vaccine? what is it effective against? What is the half life

mosquirix, falciparum, t1/2 = 5 years

What two host resistance factors confer resistance to malaria?

duffy antigen sickle cell

which type of malaria? - seldom fatal - infects young erythrocytes - fever paroxysms every 48 hours - chills, shaking for 15 minutes plus systemic sxs

vivax

Fever and chills in vivax infection are due to...

RBC schizonts

Relapse can occur in vivax due to the activation of...

liver hynozoites

Where is vivax most common?

carribean, latin america

What is the reservoir for vivax?

humans

What type of malaria? Giemsa stain showing: -Schuffner's dots

vivax

Which type of malaria? - high grade parasitemia - very high fever due to high parasite load - assoc. w/ blackwater fever - fast moving - targets all RBCs

falciparum

A patient presents with: high Hb in urine dark/black urine autoimmune destruction of kidney chillds, fever, rigor

blackwater fever, falciparum

Falciparum can lead to capillary obstruction. This occurs why?

RBC destruction leads to sticking in endothelium

this falciparum complication results in: - occlusion of capillaries with parasitized RBCs - necrosis, hemorrhage, fever, mania, convulsions and possibly death

cerebral malaria

this falciparum complication results in: frequent vomiting

gastric falciparum malaria

this falciparum complication results in: cool skin but high internal temperature sign of serious disease

algid malaria

Does falciparum have a hynozoite stage?

Which plasmodium species? double or multiple ring stages crescent shaped gametocyte maurers clefts young tophozoites and gametocytes

falciparum

What type of malaria? - infects older RBCs - 4th day paroxysms - primate reservoir - basket/band shaped trophozoites - rosette shaped schizonts

malariae

which type of malaria? similar to vivax forms hynozoite common to west africa

ovale

What type of malaria? zoonotic can be fatal southeast asia

knowlesi

What geologic characteristic has made malaria worse?

climate change

What is the main mechanism for increased malaria resistance?

efflux pumps

What is the causative agent of babesiosis/nantucket island fever?

babesia microti

This disease: - prevalent in new england during warm months - increasing issues with blood donation - deer tick vector

bebesia microti

The sxs of babesiosis are clinically similar to...

malaria

What is typical on the skin for babesiosis?

pinpoint lesions

Babesiosis is often coinfected with...

lyme disease

The following morphology/symptomatology suggests... cross like structure in RBCs sxs similar to falciparum

babesiosis

This is the destruction of motor neurons in the spinal cord resulting in asymmetric flaccid paralysis...

poliomyelitis

Polio is a ______ virus

picorna

What clinical syndromes can be present in polio infection? (5)

1. inapparent infection 2. abortive illness 3. nonparalytic poliomyelitis 4. paralytic poliomyelitis 5. Post-polio syndrome

This is the most common clinical syndrome of poliovarus. It often appears asymptomatic or with minor malaise

inapparent infx

The presence of antibodies in HIV indicates a good/bad prognosis?

bad, will eventually die of HIV or related infx

this clinical syndrome of polio virus has the following characteristics: - flaccid paralysis from lower motor neuron damage - effects less than 1% - rarest

paralytic poliomyelitis

This polio virus syndrome has the following characteristics: - muscle weakness, pain, fatigue in polio patients - can occur 30+ years after acute case of paralyzing polio

post-polio syndrome

What causes failure of remaining CNS motor units in post-polio syndrome?

overuse

Salk discovered which polio vaccine?

inactivated polio vaccine

Which polio vaccine has the following characteristics? - injected, virus killed - prevents disease/paralysis but not infection

inactivated polio vaccine

Which polio vaccine is a trivalent oral polio vaccine, discovered by Sabin

Live polio vaccine

Which polio vaccine has the following characteristics? - live-attenuated - multiplies, infects, immunizes community - back mutation to a wild type of polio is known, and 10 US cases per year

live polio vaccine

does rabies vaccine occur before or after infx?

after

Which vaccine is used in the US?

IPV

What are the usual vectors for arboviruses?

mosquitos and ticks

What are the animal reservoirs for arboviruses in the US?

birds and small mammals, often unapparent infx

Which type of arbovirus? - alphaviruses - Eastern, Western, Venezuelan Equine Encephilitis

togaviridae

Which type of arbovirus? - st. louis encephalitis - wet nile virus - dengue

flaviviridae

Which arbovirus type? -california encephalitis

bunyaviridae

A patient presents with the following manifestations. what type of virus is responsible?: - often subclinical - fever, HA, vertigo, NV, Photophobia - AMS, focal/general seizure

Arboviruses

Which virus is a flavivirus, closely related to yellow fever and St. Louis encephalitis?

west-nile

There is an antigenic cross reaction between west-nile and what two viruses?

yellow fever st. louis encephalitis

Describe the change in distribution of west-nile virus since 2000?

more widespread

What are 4 important historical clues that can point you towards west-nile?

travel hx, time of year, location, age

Which tests for WNV test for specific IgM Ab in the CSF or serum?

MAC-ELISA

MAC-ELISA for WNV may show antigenic cross reactions with what 4 other diseases?

yellow fever dengue japanese encephalitis st. louis encephalitis

are people with post-polio syndrome infectious?

What may induce long-lasting positive IgM titers for WNV?

yellow fever, japanese encephalitis vaccine

How is west nile treated?

supportive care

During arbovirus infections, days 0-5 after onset can sometimes be detected/dx with... is this reliable?

acute serum, RT-PCR not reliable

diagnosis of arbovirus infx is most reliably made with what test?

convalescent serum, IgM ELISA

Positive IgM ELISA for arbovirus indicates...

infection

What are the dead end hosts of arboviruses?

horses, humans

Immunization of horses and non-human amplifying hosts can help control ____virus infection

arbovirus

What are two major ways to prevent arbovirus infection?

eradicate vector avoid exposure

What are 2 ways of Zika transmission?

mosquito bite, STI

What prevents zika infection? (2)

mosquito avoidance, education

Diagnosis of Zika is made using what two tests?

nucleic acid test/PCR MAC ELISA

Zika shows antigenic cross reaction with flaviviruses such as...

dengue

A major concern of zika virus is___

teratogenic

This disease is considered invariably fatal once symptoms become overt...

Rabies

Describe the incubation period of rabies...

2-16 weeks to years

How long does it take for death to occur when rabies symptoms appear?

5-6 days

A patient presents with the following, concerning for... - mild fever - pharyngitis - HA - pain/burning at site of inocculation - increased sensory sensitivity

Rabies

Rabies diagnosis depends on what two factors?

exposure to bite plus symptoms

What test should be used on the suspected rabid animal vector?

FA test

What animal contact should be immediately suspicious of rabies?

bats

This virus is an enveloped, bullet shaped virus in the rhabdovirus family...

rabies

Negri Bodies are eosinophilic inclusion bodies that are pathognomonic for...

rabies

What are the rabies reservoirs in US, Canada and Europe?

skunks, raccoons, foxes, bats

What is the number 1 cause of viral encephalitis in the US yearly?

WNV

a retrospective study showed that majority of human rabies cases have/haven't been linked to bites

haven't, simple contact

How successful is the Milwaukee protocol in rabies tx?

fails as often as succeeds

What are the 3 ways to prevent rabies?

avoidance prophylactic vaccination of animals post exposure vaccination

The rabies vaccine is given with______ after contact with a reservoir...

hyperimmune serum

The quadrivalent vaccine for meningococcal meningitis is a ______ conjugate that covers which serotypes?

polysaccharide-protein A,C,Y, W135

Which media is selective for menigococcal meningitis, containing sheep RBCs and antibiotics?

Thayer-Martin Agar

Menigococcemia will present with what characteristic lesions?

petechial lesions

What two diagnostic tests detect capsular polysaccharide of menigococcal meningitis in CSF?

PCR, agglutination

A non-blanching (tumblr test positive) petechaial and pink macular rash can indicate what infection?

meningococcemia

DIC and gram negative shock can occur in what condition?

meningococcemia

Who is the only reservoir for menigococcus?

humans

Meningococcus infx requires what kind of contact?

close contact

What pathogen is the causative agent of meningococcal meningitis?

N. meningitidis

This is a fastidious, G-, kindey bean shaped diplococcus...

n. meningitidis

What two factors have significantly declined the incidence of meningitis?

1. vaccine | 2. universal GBS screening of pregnant women

S. Pneumoniae H. Flu N. Meningitidis these pathogens colonize the respiratory tract and are responsible for _____ acquired meningitis

community acquired

What is the most common way that pathogens gain access to the CNS to cause meningitis?

bacteremia and seeding to CNS

Fever, HA, Neck stiffness indicates...

meningitis

Comparing serum glucose to CSF glucose should show a decreased level in which fluid?

CSF

A pediatric patient presents with the following. These sxs are concerning for... ``` bulging fontanelle high pitched cry hypotonia paradoxic irritability hyperthermia ```

neonatal bacterial meningitis

Which three pathogens are common causes of neonatal meningitis?

S. agalactiae (G+), MC Listeria (G+) E. Coli (G-)

Vaginal and rectal screening should occur for all pregnant women between 35 and 37 weeks gestation for what?

GBS (s. agalactiae)

This is a G+ coccus with narrow zone of beta-hemolysis.

S. agalactiae

Capsular Polysaccharide Hyaluronidase Collagenase Hemolysin These are virulence factors on which organism?

S. agalactiae

Early or Late onset neonatal GBS ifx? maternal obstetric complication sxs in 1st 5 days of life bacteremia, pneumona, meningitis

early onset

Early or Late onset neonatal GBS ifx? maternal obstetric complications uncommon sxs 7 days to 3 mo of age severe bone/joint infx, bacteremia, fulminant meningitis

Late onset

Lab tests for s. agalactiae can look for ______ factor, which shows accentuation of hemolysis due to interaction with staph beta lysin

CAMP factor

What offers definitive diagnosis of S. agalactiae?

isolation from blood, CSF

AccuProbe DNA probe can give a presumptive dx of ...

s. agalactiae

E. Coli is an important cause of neonatal meningitis whose source is...

not endogenous rectal colonization of mother's vagina

What is the MC cause of bacterial meningitis?

s. pneumo

Acute purulent meningitis following PNA, other infection, or no apparent infection describes the etiology of...

S. pneumo

This meningitis causing pathogen has the following characteristics: - non-motile, G- coccobacillus - contains LOS, which is similar to LPS - associated with URI or AOM

H. Flu

This meningitis agent has the following pattern: - several days of mild antecedent infx - following deterioration, signs, sxs of meningitis

H. flu

This pathogen is a G+ motile coccobacillus. It is non-fastidious and growth between 0-50 degrees C. It is a facultative intracellular pathogen

Listeria

What are two main virulence factors on listeria?

LPS like surface component Listeriolysin O

Which listeria virulence factor has the following characteristics? - antiphagocytic - responsible for complement dependent hemolytic abs

LPS like surface component

Which listeria virulence factor has the following characteristics? disrupts phagolysosome membrane inhibits antigen processing induces apoptosis

listeriolysin O

What are 2 main manifestations of listeriosis?

sepsis, meningitis

Listeria grows on what media?

blood agar

You see "tumbling" motility on culture. This indicates what infection?

listeriosis

What is the test of choice for diagnosing listeriosis?

DNA probe (accuprobe)