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103 Cards in this Set
- Front
- Back
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what are the 4 host defense mech against skin infxns?
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keratinized skin: tough, water resistant, continuous sloughing of outer layers
sebaceous and sweat gland secretions: high salt, acidic Commensal flora Resident Mac in dermis |
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Necrotizing fasciitis is a syndrome of what part of the skin?
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subcutaneous tissues
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cellulitis is the result of what type of entry?
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endogenous entry
inlfammation in cutaneous area |
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term for severe itching?
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pruritis
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term for redness of skin?
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erythema
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what is the term for release of purulent matter (Pus)?
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suppuration
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was is crust?
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dried residue of serum, pus, or blood on the skin
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what is the hallmark of cellulitis presentation?
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pt has discomfort above what appears legitmate
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what does cellulitis look like?
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diffuse erythema
no well demarcated edges not raised |
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what are the 5 most likely org for maculopapular exanthems?
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strep. pyogenes
rubeola virus rubella vrus HHV 6 Parvo B19 |
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what are the 4 most likely org for vesicular exanthems?
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varicella-zoster
coxsackie A Pox viruses HSV 1 and 2 |
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what are the 2 most likely org for Toxigenic Rashes?
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staph. aureus
strep. pyogenes |
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what are the 3 most likely org for abscesses?
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actinomyces isreali
pasteurella multocida staph. aureus |
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what are the 3 most likely org for folliculitis?
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Candida albicans
Pseudomonas aeruginosa staph. aureus |
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what are the 2 most likely org for impetigo?
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staph auerus
strep pyogenes |
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what are the 4 most likely org for pustules?
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Bartonella henselae
Candida albicans Erysypelothrix spp Nocardia |
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what are the 2 most likely org for Necrotizing fasciitis?
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Clostridium perfringens
Strep pyo |
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what are the 5 most likely org for ulcers?
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Francisella tularensis
leishmania spp Mycobacterium spp Sporothrix schenckii Vibrio vulnificus |
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what are the 2 most likely org for Eschars?
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orf virus
Bacillus anthracis |
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what are the 3 most likely org for Tinea-cutaneous mycoses?
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Malassezia fufur
Microsporum, Trichophyton and Epidermophytn species |
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what are the 2 most likely org for warts?
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HPV
Molluscum contagiosum |
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what is the most likely org for vescicular lesions?
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HSV 1 and 2
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what are the 11 most likely org for eye infxns?
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adenovirus
Acanthamoeba castelanii Bacillus cereus Chlamydia trachomatis CMV H. flu Pseudomonas aeruginosa Staph. aureus Strep. pyo T. cruzi Toxoplasma gondii |
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what is a exanthem?
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eruptive disease (like measles) or its symptomatic eruption
widespread rash |
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all exanthems are caused by viruses with what exception?
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strep pyogenes-Scarlet Fever
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when can you call something a bullae?
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when it is vesicular rash that is larger than 0.5 cm
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waht is ecchymoses?
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large purpora: when small petechia coalesce
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what are the childhood rash syndromes: First, Second, Third, Fifth?
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first disesae: Rubeola
second disease:Scarlet fever third disease: Rubella (german) fifth disease:Erythema infectiosum "slapped cheek" |
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Rubeola is waht ? Rubella?
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Rubeola: measles
Rubella: German measles |
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Family, Genus and Species for Rubeola
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Paramyxovirus
Morbillovirus Measles virus |
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Family, Genus and Species for Rubella
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Togavirus
Rubivirus Rubella virus |
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Family, Genus and Species for Erythema Infectionsum (fifth disease)
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Parvovirus
Parvovirus B19virus |
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Family, Genus and Species for Roseola (exanthem subitum)
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Herpesvirus
Gamma virus HHV 6 |
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Family, Genus and Species for Varicella (Chickenpox)
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Herpes virus
Alpha virus Varicella Zoster Virus |
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Family, Genus and Species for Hand-Foot Mouth
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Picornavirus
Enterovirus Coxsackie A virus |
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characteristics of Rubeola?
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ss-sense RNA (b/c paramyxo)
replicates in cytoplasm enveloped transmitted respiratory highly contagous |
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waht is the attack rate for Rubeola?
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90% attack rate
highly contagous |
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who is at risk for Rubeola?
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unvaccinated
children 2-5 |
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where does Rubeola bud from?
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plasma membrane
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what is on the surface of Rubeola? what does it bind to?
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HN glycoprotein spike that binds to CD46
F fusion spike that facilitates uptake of virus by host cells*indcues cell-cell fusion to form multinucleated giant cells |
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avg. incubation pd for Rubeola?
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10 days
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describe the clinical presentation of Rubeola?
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at the end of 10 day incubation: starts with fever 101, 3 C's, and photophobia
DX signs: Koplik spots on buccal mucosa and throat maculopapular rash which starts on face and spreads to trunk and includes**palms and soles |
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waht is pathognomonic for Rubeola?
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Koplik spots: bluish-white to grey spots that dissapear at the onset of rash
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where is the maculopapular rash of Rubeola? why does it occur?
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starts on face, spreads to trunk and includes palms and soles
T cells targeting infected endothelial cells in small blood vessels |
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approx 4 days after the Rubeola rash appears what is the state of the infxn?
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pt is no longer infectous
see appearance of serum antibodies |
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what are the sequale of Rubeola?
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postinfectious encephalitis
subactute sclerosing panencephalitis (SSPE) no resoln of acute infxn due to defective cell mediated immunity |
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the rash of Rubeola is due to waht 2 things?
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viral replication
immune response :T cells targeting infected endothelial cells |
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what vitamin has been found to reduce the severeity of Rubeola in malnourished populations?
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Vit A
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when is MMR given?
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12-15 months and then at 5-6yrs
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if you are immunocompromised, what should you receive for Rubeola infxn?
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immune serum globulin: less than 1 yr old or with impaired cellular immunity
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which rash would you describe as confluent in spots?
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Rubeola measles
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what are the 4 Sequelae of measles?
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2ndary bacterial infxns
giant cell pneumonia meningitis/encephalitis subacute sclerosing panencephalitis |
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when does SSPE develop?
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1-10 years after initial measles infxn
progressive usually fatal CNS disease |
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waht are the signs of SSPE?
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first signs: behavioral
loss of motor control and coordination: myoclonic seizures speech ands swallowing impaired |
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risk factors for SSPE?
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aquiring measles at an early age (under 2)
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what sequalea is associted with defective forms of the measles virus in the brain
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SSPE
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characteristics of Rubella virus
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ss + sense linear RNA
enveloped transmitted resp with discharges from nose and throat of infected person as well as TRANSPLACENTAL |
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when is Rubella most contagous?
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when rash is erupting but virus shed from 7 days before until 4 days after onset
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who is at risk for Rubella?
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unvaccinated populations
children 5-9 **unborn fetus |
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what must rubella and rubeola bring with them to replicate?
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RNA dep RNA pol
Rubella: ss+sense RNA Rubeola: ss-sense RNA |
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Rubella is inactivated by environmental factors unlike what other cause of childhood exanthems?
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Rubeola
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how are german measles different clinically from measles?
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german: no photophobia, low fever
many cases are subclinical unlike in Rubeola wehre most infections result in clinical disease |
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clinal presentation of german measles?
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LOW fever on first day
maculopapular rash (starts on face and moves to trunk) cervial and occital lymphadenpathy |
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the rash of Rubella is associted with what?
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immune complex formation when Ab titer is high which may result in polyarhralgia in the patient
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what happens in congenital Rubella syndrome?
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caused by transplacental transmission
virus acts as a teratogen during 1st trimester*** resulting in birth defects *primary targets in fetus: heart, eyes, CNS |
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what organs are targeted in Congenital Rubella Syndrome and what is the result?
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Heart: primary ductus arteriorsus
Eyes: cataracts, glaucoma, blindness CNS: MR, deafness |
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is a baby born with Congenital Rubella Syndroma a health risk?
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yes! the infant will shed the virus for months after birth so can act as a reservoir/source
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what is the primary site of replication of Rubella?
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pharyngeal tissues
person is infectous as long as the virus is produced in the pharynx |
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what is the best way to ID/Dx Rubella?
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serology: IgM peak as measure of acute recent exposure
*same for Rubeola |
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what is the problem with a pruritic rash?
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when it is itched it is now prone to 2ndary bacterial infxns
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prevention for Rubella?
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live attenuated MMR
life long immunity in MOST |
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what is differnt about the rash appearenc of Rubella than Rubeola?
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Rubella lesions are less intensily red and rarely if ever coalesce**
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circulating Ab can block the transfer of Rubella from where?
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block spread from 2ndary infxn sites: lymph nodes, liver, spllen
block primary and secondary viremia block transfer to skin or placenta |
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what should you do in a woman that wants to get pregnant and thinks she was exposed to Rubella?
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check Ab titer
if greater than 1:64 use birth control for 3 months get vaccinated |
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primary viremia of Rubella causes?
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rash to develop due to I-C formation
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if mother is sero neg for Rubella, what can occur?
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congenital rubella syndrome
viruse goes through typical progression then spreads via 2ndary viremia to fetus |
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characteristics of parvovirus B19
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ssDNA (-or+ sense)
linear naked** |
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where does B19 virus replicate?
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nucleus bc ssDNA
must make dsDNA replicative form to do so |
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what childhood exanthems are transmitted transplacental?
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Rubella
B19 virus |
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who is at risk for B19?
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elementary age
parents of children with B19 unborn fetus* |
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replication of B19 virus requires what of the host cell?
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that the host be undergoing DNA replication; they cannot initiate DNA synthesis so these viruses are restricted to the dividing cells of the body such as erythopoitic and immune systems
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in which cells does B19 virus infect?
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only dividing cells like erythroid precursors and immune systems bc requires that the host cell be undergoing DNA replication
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what does the B19virus bind on host ?
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erythroid precursor receptor GLOBOSIDE ~ P Ag
this is presnet on endothelial cells and causes vasculitis |
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what is the disesase that B19 virus causes? how does it prseent?
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Fifth disease or Erythema Infectiousum
non specific prodromal illness 2-5 days later: slapped cheek rash rash followed by lacy, reticulate maculopapular body rash on trunk and limbs |
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what are the clinical disease names for B19virus?
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erythema infectiousm
fifth disease slapped cheek syndrome |
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what disease is associated with circumoral pallor?
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circumeral pallor = bilateral inflammation of the cheeks
Slapped Cheek syndrome/ Erythema Infectiosum/Fifth disease |
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in which childhood exanthem do we see a drop in hemoatocrit and pancytopenia that is transient?
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Erythema Infectiosum
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Aplastic crisis can occcur as a result of what disease in what population?
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B19 Virus-Erythema Infectiosum
pts with underlying anemias: sickle cell anemia Tx: transfusion |
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what are the 3 huge clinical expression hallmarks of B19virus?
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1. Erythema Infectiosum with slapped cheek syndrome
2. Aplastic anemia 3. Hydrops fetalis |
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why is impt to diagnose B19 in pregancy?
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b/c of spontaneous abortion and need to differentiate from Rubella which is more likley to lead to congenital anomalies
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prevention from B19 virus?
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no vaccine
infection provides long lasting immunity |
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what does it mean when a pts serology for parvovirus shows IgG + and IgM-?
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past infxn
pt probably immune |
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what does it mean when a pts serology for parvovirus shows IgG+ and IgM+?
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ongoing or recent infxn
fetus may be at risk if prgenent |
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lacy reticulate maculopapular body rash
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parvovirus B19
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characteristics of HHV6?
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dsDNA
linear enveloped |
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risk factors/high risk ppl for HHV6?
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children 6mo-12mos
immunocomprimsed |
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what is considered the most common childhood exanthem?
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HHV6
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where does HHV6 bud from?
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nucleus then moves cell to cell via fusion
leaves with only 1 membrane derived from inner nuclear membrane |
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appearence of HHV 6 infected cells?
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larger than normal
inclusions in both cytoplasm and nuclus** |
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clinial disease of HHV6?
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Exanthem subitum (Roseola)
3-5day high fever fever ends then rose-colored macular rash on face and trunk |
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what is the Roseola rash due to ?
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I-C formation
seen on trunk and face |
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the childhood exanthems can be Dx how?
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serology (Ab titers) and PCR
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what the 3 impt descriptions of Scarlet Fever rash apperance?
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1. circumoral pallor (bilateral inflammation on cheeks)
2. Pastia's lines 3. Positive blanching |
