Clinical Virology Flashcards
What is the difference between an exanthem and an enanthem?
an exanthem is expressed on the cutaneous surface
an enanthem is expressed on mucosal surface
What does HPV cause?
common warts, plantar warts, genital warts, condylomata
How is HPV transmitted?
person to person by contact or through fomites
does not have any connection to a specific season
What is the incubation period for warts?
3 months to many years
Besides clinical inspection, how can the diagnosis of HPV be made?
apply acetic acid and see if it turns white
What is the treatment for HPV?
liquid N2, various acids, podophylium, last, surgical
What virus causes molluscum contagiosum?
poxvirus
What does mulloscum contagiosum look like?
discrete, papular waxy lesions that gradually develop on the surface of skin. Each will have an umbilicated appearance
usually only a few are present, but in a generalized location
How is molluscum contagiosum spread?
humans are the only known source of infection
spread by contact or through fomites
non-seasonal
How long is the incubaton period for moluscum contagiosum?
2 to 7 weeks, but as long as 6 months in some
What is the management of molluscum contagiosum?
mechanical removal of the central core which contains the virus
freeze with liquid N2, burn with acids
What does variola (smallpox) look like?
a vesiculated rash that spreads from a distal distribution to central.
people will have associated headache, fever (102-105 degrees(, extreme malaise and muscular pains preceed the rash.
THe rash will develop with same stages in local crops and become encrusted during development
THIS WILL LAST FOR 2 WEEKS
resolves with significant scarring
the hemorrhagic form is highly fatal
How is small pox spread?
direct contact with skin lesions and mucous membranes, human transmission although some animal poxviruses can be transmitted
winter and spring are the peak incidences
WHat is the management of smallpox?
strict isolation
symptomatic treatment
we previously used active immunization, but stopped giving the vaccine in the 70s because we cleared it out of the US
Who gets Orf virus?
sheep herders
What does Orf virus present as?
Starts with an erythematous papule - usually on the fingers, which vesiculates
typically just a solitary lesion
How is orf virus spread?
from working with sheep - it’s a zoonosis usually seen in spring after shearing season
What is the technical name for what Orf virus causes?
Ecthyma contagiosum
What is the management of Orf virus?
the duration is usually 30 to 40 days and resolves spontaneously with only symptomati care.
wear gloves to prevent it in the future
WHat virus causes chicken pox?
varicella zoster - a herpes virus
WHat is the typical clinical course for a chickenpox infection?
- general malaise with mild fever
- pruritic rash develops centrally on head and trunk and then spreads to periphery
- Rash rapidly develops from macule and papule to vesicle in 24 hours
- Rash clears in 10 days
WHat complication can occur if you give a child with chickenpox aspirin?
Reye syndrome
When is someone with chickenpox able to pass it along to others?
from 1-2 days before the rash starts to about when the rash begins to crust over (about 5 days)
How do you manage chickenpox?
strict isolation
do NOT use aspirin
aboid hospitalization exposure to immune incompetent individuals
vitamin A
orgal acyclovir within 24 hours maybe helpful, but not by that much
we can use active immunization now
What does the clinical course look like for herpes simplex?
you get a stinging erythematous lesion at the junction of the skin and lip which proceeds to a crusted sore over a few days but lasts up to 10 to 12 days
no systemic symptoms
you can also get lesions of the oral cavity or genital region
What is a herpetic whitlow?
a herpes lesion on the finger tip seen in kids who have oral herpes infections and suck their fingers
How is herpes simplex transmitted?
direct contact, sexual contact, birthing contact
non-seasonal but associated with stress
How long are people infected with herpes?
it’s a latent and recurrent infection, so always
How can you manage herpes simplex?
drying agents
acyclovir ointment locally
oral or IV acyclovir, famciclovir, valacyclovir, or penciclovir
What is the issue with herpes passed from mother to infant during birth?
newborns will contract a very severe form which is often fatal
How does exanthem subitum (roseola) present clinically?
Usually in infants
they develop high fever with minimal respiratory symptoms preceding
the patients will not be toxic - usually still playful
after 3 days the fever will break, but you get a fine maculopapular rash that develops on the neck and trunk which will last for about 2 days
What virus causes exanthem subitum?
herpes virus 6 and 7
How is roseola transmitted?
probably through nasopharyngeal droplets
When are patient swith roseola infectious?
during the early febrile stage - once the rash starts they’re not infectious anymore
What is the main sequela of concern in roseola?
febrile seizure because of the high fever
What is the management for roseola?
antipyretics to avoid febrile seizure
no isolation really needed
gangiclovir?
Why are patients with roseola frequently misdiagnosed with a penicillin allergy?
They are given the penicillin during the fever and then when they develop the rash a few days later it is assumed it’s a reaction to the penicillin
How does ebstein barr infection present?
often with sore throat, mild fever, enlarged lymph nodes and extreme tiredness.
can have splenomegaly
can get a maculopapular rash on the runk
jaundice may occur in severe cases
What will a blood smear show in an epstein barr infection?
atypical lymphocytes
How is mono transmitted?
close contact and pharnygeal secretions
not seasonal
How long is the incubation period for mono?
acutally quite long - about 30 to 50 days
How long is someone infectious with mono>
can be infectious for months after symptoms clear
What test is used to check for mono?
a mono spot test to check for heterophile antibodies
How is mono managed?
symptomatic treatment
avoid contact sports for the spleen
possible steroids
observe for jaundice
What drug do you NOT want to give someone with mono?
Ampicillin - it makes the rash worse
What disease does coxsackie virus cause?
hand, foot, and mouth disease
(if just the mouth = herpangina)
How does hand, foot and mouth disease present?
malaise and mild fever
sore throat
lesions in mouth and on extremities
enanthem occurs withint one or two days after onset of symptoms and exanthem is after that
lesions can ulcerate in the posterior pharynx
lesions clear within a week
How is hand, foot, mouth spread?
nasopharyngeal droplets
saliva
fecal-oral
peaks in summer and early fall
How does echo virus present?
flu-like process with mild fever, malaise, abdominal cramping, diarrhea and a non-specific maculopapular rash on the trunk
the rash will fade over a 5-day period after the other symptoms have resolved
How is echo virus transmitted? When?
fecal to oral route
peaks in summer and early fall
What disease is caused by parvovirus?
Fifths disease - erythema infectiosum
How does fifths disease present?
mild upper respiratory illness
red, slapped cheek rash on face
face rash faes and can be replaced with a lacy rash on the upper extremities
the extremity rash may fade, only to return in a couple of weeks
maybe joint complaints
How is parvovirus spread? When?
nasopharyngeal droplets and maybe via blood
peaks in spring
When is a patient infectious with parvovivrus?
from before onset of the rash to shortly after rash appears
WHy are teachers particularly concerned about parvovirus?
it’s a big issue for teachers who might be pregnant because it can cause significant problems if exposure in 1st trimester
What does paramyxovirus cause?
rubeola = measles
How does measles present?
In an unvaccinated individual…..
upper respiratoy symptoms with rhinitis and cough followed by conjunctivitis
discrete red rash that gradually becomes confluent spreading from central to distal
fever
oral lesions called koplik spots is totally diagnostic
How is paramyxovirus spread? when?
nasopharyngeal droplets and direc tcontact
peaks in winter and spring (and in two to 5 year cycles)
When is a patient with measles infectious?
1-2 days before onset of symptoms to the 4th day after onset of rash
How is measles managed?
you can use immune globulin in exposed susceptibles
isolation, symptomatic meds, vitamin A
prevent with actieve immunization!
What disease does Toga virus cause?
rubella = german measles
(bastard scarlatina)
How does rubella present clinically?
upper respiratory symptoms
malaise
low grade fever
fine maculopapular rash develops on upper body and spreads to lower body
rash clears rapidly over 3 days
Enanthem = forchheimer spots on soft palate
joint pain
cervical lymph nodes - particularly the suboccipital and posterior auricular nodes
How is toga virus spread? When?
nasopharyngeal droplets, direct contact, maybe stool and urine
peaks in winter and spring; occurs in 6-9 year cycles
WHen is a patient with rubella infectious?
7 days before onset of rash to 5 days after onset of rash
How is rubella managed?
symptomatic meds
isolation
immun globulins in early exposure - especially in susceptible pregnant women
we have active immunization against this one
What is the worry with rubella in pregnant women?
It can be transplacentally given to the baby
they will have blueberry baby syndrome with symptoms of the CNS, cardiac, hearing, eyes and skin
How is dengue fever spread?
mosquito bites!
not present above or below 25 degrees N or S
Not seen in the winte rmonths
How does dengue fever present?
high grade fever suddenly lasting for 1-5 days
joint pain
sore throat and cough
general malaise
vomiting
after the fever a non-descript, generalized rash develops sparing the soles and the palms.
patient iwll be ill and toxic
there is a fatal hemorrhagic form
What are somethings you shoul dinclude on yoru differential diagnosis when someone presents with a fever and rash?
pityriasis rosea
scarlet fever
impetigo
meningococcemia
What is the hallmark of pityriasis rosea?
the herald patch following a dermatomal pattern
What will present with perioral palor, sandpapery rash on face, and red lines in skin creases?
Scarlet fever - streptococcus
