Viral Infections I Flashcards
What is the smallest of the microbes?
virus
What do viruses depend on in order to reproduce?
host cell
(human, animal, bacterial, plant)
Can viruses survive on inanimate objects?
YES
What are some vectors for viruses?
Mosquitos, ticks, bats
What are the three types of viruses?
DNA virus
Single stranded RNA virus
Retrovirus
How are DNA viruses classified?
they invade and replicate in host cell nucleus
How are single stranded RNA viruses classified?
they invade and replicate in host cytoplasm
How are retroviruses classified?
Use of reverse transcription to create a DNA copy of their RNA genome and inset it into the host cell- becomes a part of the host RNA
Describe a viruses pathophysiology
Virus attaches to host cell
Viral DNA or RNA then enters the host cell and replicates inside host cell
The host cell typically dies-releasing new viruses that move on to infect other host cells
Once a host cell is infected, is the virus able to lay dormant?
YES isnt that crazy? They can lay dormant and can reactivate at a later time
How are viruses transmitted?
Respiratory secretion (airborne droplets)
Enteric secretions (fecal-oral route)
Sexual contact (direct mucosal contact, semen/body fluids)
Blood (contaminated needles and blood products)
What kind of virus is Herpesvirus?
DNA virus
What family is the herpes virus in?
Herpesviridae
How many types of herpes are there that infect humans?
8
Can a herpes virus be latent in a host cell?
Yes, after an infection, herpesvirus can remain latent within specific host cells and reactivate at a later date
Can herpesvirus survive outside of a host?
nope!! not for long. transmission usually requires intimate contact
Can herpesvirus mutate host cells into a malignant cell?
YES, watch yaSELF
What are the 8 human Herpesvirus
Herpes simplex virus (HSV) type 1
Herpes simplex virus (HSV) type 2
Varicella zoster virus (VZV)
Epstein-Barr virus (EBV)
Cytomegalovirus (CMV)
Human Herpesvirus (HHV) 6-7
Human Herpesvirus (HHV) 8
which herpesvirus is only seen in AIDS patients?
Kaposi sarcoma
Human herpesvirus (HHV) 8
What herpesvirus often presents as a rash in little babies?
Roseola infantum
Human herpesvirus (HHV) 6-7
Where does HSV 1 typically present?
it affects the oral region
(ie herpes labialis, gingivotomatitis)
Where does HSV 2 typically present?
affects the genital region
What are some risk factors for contacting HSV?
Female
History of STDs
Multiple sexual partners
Contact with sex workers
WSW
How is HSV transmitted?
skin to skin contact
the fluid from the vesicles releases HSV but you are able to transmit the infection without actual presence of vesicles
Once you’re infected, it’s a lifelong thing
It may lay dormant for months or years
How does does HSV typically present?
Mucocutaneous lesions
Where does HSV 1 typically present?
vesicles form crusts and moist ulcers
can be singular or grouped
found in lips, nares, or mouth
Also found on fingers -Herpetic whitlow
Where does HSV 2 typically present?
genital region (external genitalia, vaginal canal, perianal)
multiple, grouped, painful vesicles
may have pain or lesions before appearance of lesions
What are the associated symptoms with HSV oral infection?
pain, burning, tingling of skin
pain with eating (if inside mouth)
swollen lymph nodes
low grade fever
What are the associated symptoms with genital infection?
Pain, burning, tingling of skin!
Dysuria*
Cervicitis*
Urinary retention*
Swollen lymph nodes
Fever, body ache
How does HSV present clinically?
after initial infection, HSV remains dormant in nerve ganglia until flares occur
What are HSV periodic symptomatic reactivations called?
flares
How do HSV flares typically present?
febrile illness
hormonal changes (pregnancy, menstrual cycle)
Physical or emotional stress
Overexposure to sunlight
How does HSV Keratoconjunctivitis present?
often unilateral
initially present with blepharitis
impaired visual acuity-can lead to blindness
Pain, sensation of something in eye, photophobia
How is HSV Keratoconjunctivitis transmitted?
direct inoculation
-neonates
trigeminal nerve spread
What are some less common HSV presentations?
HSV encephalitis
Disseminated
Esophagitis
Proctitis (inflammation of rectum)
How do you diagnose HSV?
Characteristic clinical appearance
cultures-vesicular fluid or scraping of crust/ulcer
PCR- CSF for HSV encephalitis
Tzanck smear
What would you see on a Tzanck smear that clues you in to a herpetic infection?
presence of multinucelated giant cells- positive for herpetic infection
Can also be positive with Varicella; does not tell you if HSV 1 or 2
How do you diagnose Keratoconjunctivitis?
Appearance of dendritic lesions on fluorescein stain and slit-lamp examination
Requires immediate referral to Ophthalmologist!
What is the treatment for HSV?
-Outbreaks are self-limiting
healing typically takes 10-20 days with initial outbreak and 5-10 days with recurrences
-There is no definitive cure for it though
-Antivirals
shorten duration, lessen severity
must start at first sign of outbreak
patients with frequent recurrences can take as prophylaxis
-symptomatic relief
-secondary bacterial infections
what are some topicals that can be used for HSV?
topical anesthetics (gingivostomatitis)
-dyclonine
-benzocaine
Rx viscous lidocaine rinse
AND
topical antibiotics (mupirocin, bacitracin)
How do you make lidocaine rinse (Magic mouthwash)
1/3 lidocaine/xylocaine
1/3 maalox
1/3 benadryl
3oz, 2R TID
baby safe (18 months +)
What antivirals are given as a tx for HSV?
acyclovir (PO, IV, liquid, and topical)
famciclovir (PO)
valacyclovir (PO)
topicals:
penciclovir
docosanol-OTC
What is the treatment for ophthalmic HSV keratitis?
trifluridine (viroptic)
What is the MOA for HSV antivirals?
inhibit herpes viral DNA synthesis and replication
What HSV antivirals are prodrugs? Where do they get converted into their active form?
valacyclovir and famciclovir are pro drugs
converted to active form in GI tract
Where is acyclovir (HSV antiviral) metabolized?
in the liver
how are HSV antivirals primarily excreted?
Renally!!
Use with caution in renal failure
What are some adverse reactions caused by HSV antivirals?
MC:
GI symptoms
HA, dizziness, malaise
anthralgia
Can cause elevation in BUN/Cr-check at baseline and monitor if prolonged use
MS:
Leukopenia, thrombocytopenia
Neurologic manifestations-hallucinations, psychosis, seizures
What pregnancy category are HSV antivirals in?
Cat B
When would you use foscarnet as a HSV antiviral?
only use in HSV if severe strain is resistant to acyclovir
M/C use for CMV infections in AIDS patients
When would you use ganciclovir and valganciclovir as an HSV antiviral?
only used for CMV (cytomegalovirus) infections in immunocompromised patients
What are some black box warnings for foscarnet, ganciclovir, and valganciclovir?
seizures
renal impairment causing toxicity-hematologic abnormalities
possible carcinogenic
What is the treatment for PRIMARY AND RECURRENT HSV genital infection?
oral acyclovir (400 mg TID)
valacyclovir (500-1000mg BID)
famciclovir (250 mg TID)
treat initial episode for 7-10 days
recurrences can often be reduced to 3-5 days
Tx for initial episode should begin 48 hours of onset!
recurrences should initiate tx at first sx of onset (w/in 24 hours)
How would you treat Primary and recurrent HSV oral infection?
oral antivirals (same as for genital herpes)
Topical 1% hydrocortisone 5% acyclovir cream, penciclovir
OTC docosanol (Abreva)
What are some tx options for recurrent HSV prophylaxis?
acyclovir (400 mg BID)
valacyclovir (500mg QD)
famciclovir (250 mg TID)
What treatment would you use for keatitis?
topical trifluridine ophthalmic drops
oral acyclovir
what would you use to treat disseminated/neonatal disease?
IV acyclovir
How could you counsel a pt to prevent contracting HSV?
barrier methods during sex
c-section for women with active genital lesions
sunscreen can reduce the occurrence of herpes labialis
What is the etiology for Herpes Zoster (shingles)
It is the varicella zoster virus (VZV)
initial infection results in chicken pox
VZV remains dormant, then reactivates causing Herpes Zoster (shingles)
Risk increases with age (>60) and immunocompromised persons
What are some CDC facts about shingles (probz not testable)
1 out of 3 people will develop shingles in their lifetime
1 million people treated annually
How does Shingles present?
skin lesions resembling chickenpox
evolution of macules-papules-vesicles-crusts***have to present with all 4!!
Lesion sits atop an erythematous base “dew drop on rose petal”
Severe pain commonly precedes rash
Follow dermatomal distribution
What part of the body are shingles typically most common?
typically a unilateral dermatomal distribution along thorax and lumbar regions
trigeminal nerve involvement:
-herpes zoster ophthalmicus- most serious
-Lesions in corner of eye and side of nose (Hutchinson’s sign)
-Can cause blindness with severe eye involvement
What complications are seen with herpes zoster?
Post-herpetic neuralgia PAIN
-occurs in 30-40% of patients >60 years of age
-prolonged debilitating pain
Bacterial secondary skin infections
Vision loss (Herpes Zoster Ophthalmicus)
Bell’s palsy
What are some treatment options for Herpes Zoster?
Typically Self limiting
Treatment Goals
Medications
-acyclovir, valacyclovir, famciclovir
Treatment should be started within 72 hours of of onset of symptoms
What are the treatment goals for shingles?
reduce duration
lessen severity of symptoms
reduce risk of post-herpetic neuralgia
What medications are used for the treatment of herpes zoster?
acyclovir, valacyclovir, famciclovir
Treatment should be started within 72 hours of onset of symptoms
How would you treat Herpes Zoster Ophthalmicus
Emergency
Admit for IV acyclovir
Topical steroids
How would you treat Post-herpertic neuralgia?
Pain management
(opioids, TCA’s, gabapentin)
What are some ways you can counsel someone about shingles virus prevention?
Recombinant vaccine “zoster vaccine”
offer to persons >/50 years of age
(2 vaccines required 2-6 months apart) whether or not they received Zostavax
REDUCES SHINGLES and PHN 90% according to CDC
What is the primary reason to vaccinate someone against the shingles vaccine?
POST-HERPETIC NEURALGIA
What is human herpesvirus 4 also known as?
EPV
What is the causative agent for Monocucleosis?
EPV
Do all mono carriers show symptoms?
Nope!! You can be an asymptomatic carrier!!
>90% of adult population worldwide have virus
It persists for a lifetime!
How is mono/EBV transmitted?
Saliva, blood products
What are some symptoms for EBV?
malaise/fatigue
sore throat
tonsillar enlargement
myalgia
What are some signs for EBV?
lymphadenopathy
Phayngeal irritation
Splenomegaly (50% of patients)
Palatal petechiae
Maculopapular rash (20% of patients)
-if given ampicillin (incorrectly)-rash seen in >90%
How do you diagnose mono/EBV?
Serology
-Mononucleosis spot test (Monospot)
-Heterophile agglutination (HA) antibody test
Blood smear
-atypical large lymphocytes
CBC
-leukopenia
-lymphocytosis
EBV antibodies
-IgM antibodies to EBV rise in acute infection
IgG antibodies to EBV persist for life
What are some complications that can arise from EBV?
Splenomegaly/splenic rupture
-rupture is rare
-indication for hospitalization
-avoid strenuous activity/contact sports
Hepatitis
-watch for s/sx: jaundice, N/V
Indication for hospitalization
Monitor LFTs
CNS involvement-infrequent
What supportive treatment could you give a pt with EBV?
Fluids
Antipyretics
ANTIVIRALS NOT INDICATED
ANTIBIOTICS NOT INDICATED
hospitalize if severe splenomegaly, hepatitis, CNS involvement, severe thrombocytopenia, or other complications
What is the prognosis for someone with EBV?
Fever, sore through (resolves in 10 days)
LAN, splenomegaly (resolves in 4 weeks)
Fatigue-can linger for months
Can rarely have a chronic EBV syndrome
What are some diseases associated with EBV?
Burkitt lymphoma, B-cell malignancies in Immunocompromised persons, Nasopharyngeal carcinomas
What is CMV?
Cytomegalovirus
How much of the population has CMV?
60-90%
It’s a (mostly) asymptomatic latent infection
It’s a severe illness confined to immunocompromised persons
How is CMV transmitted?
blood, bodily fluids, and transplacentally
What are the three CMV Clinical syndomes?
CMV inclusion disease-newborns
Acute viral syndrome-immunocompetent persons
CMV disease- immunocompromised person (HIV)
What clinical syndromes present from CMV inclusion disease in newborns?
Hepatitis, mental retardation, hearing loss, stillbirth
What clinical syndromes present from Acute viral syndrome-immunocompetent persons?
fever, malaise, arthralgias
mono-like illness without the pharyngitis
What clinical syndromes present from CMV disease-immunocompromised persons (HIV)?
CMV retinitis
GI (gastritis/colitis), Respiratory (pneumonitis), Neurologic (encephalitis), CMV
How do you diagnose CMV?
Serologic testing
How do you treat CMV?
*serious illness (CMV retinitis, encephalitis, etc)
gangiclovir (zirgan) or valganciclovir (valcyte)
foscarnet (foscavir)
How many genotypes of HPV are there?
over 100 different genotypes of the virus
just infects epithelial tissue
Many of the strains are transient
some strains are lifelong
What strains of HPV cause genital warts?
HPV 6 and 11
What strains of HPV have been found to cause/be related to cervical cancers?
16** and 18
Gimme some facts about condyloma acuminata
sexually transmitted (vaginal, oral, anal)
more common in women
incubation period 3 weeks to 8 months
most are transient and resolve in 2 years
increase risk of malignancy
Many are asymptomatic- but can still transmit the virus
How does condyloma acuminata present clinically?
scaly, raised, skin colored to pearly lesions
-often occur in clusters
-may be pedunculated
Occur anywhere in genital, perineal, or anal region
May have associated pruritus, burning, bleeding, or pain
Large clusters can interfere with intercourse or defecation
How do you diagnose condyloma acuminata?
clinically
determine extent of involvement:
anoscopy, speculum, speculum exam, colposcopy
How do you treat HPV condyloma cuminata?
Chemical destruction (podophyllin/Podofilox or Imiquimod)
Cryotherapy in office
Systemic treatment (interferon)
Laser surgery OR surgical excision
What are the steps in cancer development in regards to HPV?
HPV virus infection-sexually transmitted
Persistence of HPV infection
Progression of normal epithelial cells to precancerous cells
Development of carcinoma
What cancers can HPV cause (5 total)
Cervical and Anogenital are the most prominent ones
Oropharyngeal
Vulvar
Penile cancer
How does HPV and cervical/anogenital cancer?
typically asymptomatic
Found on routine screening
-pap smear
What is the treatment for cervical cancer?
laser ablation
“cone biopsy”/LEEP
surgery
What preventative measures can a patient take in regards to HPV?
Gardasil-protects against HPV strains 6, 11, 16, 18, 31, 33, 45, 52, and 58
Who is the HPV vaccine recommended for?
Females and males aged 11-12
Can be administered as young as 9
Catch up for females up to 26; males 21
No recommendations for >26; but approved up to age 45
Goal is to start before female or male is sexually active
In 2012, ACIP also recommended routine immunizations in males aged 11-12
What causes the seasonal flu?
influenza virus A or B
Everchanging strains
-antigenic drift-slow, gradual change
-antigenic shift-sudden change
–little to no immunity/responsible for pandemics
Occurs in outbreaks-primarily in winter months (Oct-March)
Spread through infected persons via respiratory droplets
-also by touching contaminated objects
What is the Flus incubation period?
1-4 days
What are the two strains for swine flu?
H1N1 (pandemic in 2009)
H3N2v (outbreak in US in 2012)
What are the two strains for bird flu?
H5N1
china, Asia, Middle East
“highly pathogenic” -60% mortality rate
Highest rates in 2003 (dropping since)
H7N9
China only
How does the flu present clinically?
sudden onset fever, chills, headache, myalgia, malaise
Non-productive cough, sore throat, nasal discharge
PE is unremarkable
Complications that can rise from the flu?
Secondary bacterial infections-pneumonia, sinusitis
Rhabdomyolysis, myositis
CNS involvement-encephalitis, aseptic meningitis
Cardiac complications
How do you diagnose the flu?
Rapid Influenza Diagnositc test (RIDTs)
NP swab, nasal aspirate
detects both A and B within minutes
Problem-high false negative rate
Viral culture
-more definitive testing
should be conducted for all hospitalized patients or if different strain suspected
results in 2-3 hours; but culture may take up to 5 days
What is the treatment for the flu?
Antipyretics
Fluids
Analgesics
Antiviral medications
What are some antivirals that you can use on the flu?
Neuraminidase inhibitors (FDA approved to treat seasonal flu, Covers A and B strain)
NMDA Receptor antagonists (cover influenza A only)
What antivirals cover both influenza A and B?
Neuraminidase inhibitors
oseltamivir (Oral)
Zanamivir (Inhalation)
Peramivir (IV)
What are some antivirals that only cover influenza A?
NMDA Receptor antagonists
Amantadine
rimantadine
What neuraminidase inhibitor information should we know for the flu?
used for treatment and prophylaxis of flu
(except peramivir-treatment only)
need to start medication within 48 hrs of symptoms
Oseltamivir 75mg po BID x5 days
safe for all ages (birth and up, but prophylaxis 3 months and older only, dosage based on age and weight
What are some AE from using Neuraminidase inhibitors (to treat the flu)?
MC: N/V/D, headache
Most serious: Bronchospasm with Zanamivir
can cause behavioral disturbances (Rare)
Very few drug interactions
Oseltamivir primarily renally excreted (Adjust for renal failture)
How do we counsel a patient on flu prevention?
Routine annual vaccinations of all persons aged 6 months and older
Should receive vaccine in October
Who is the flu vaccine particularly important for?
Young children
Person >50
Persons with chronic cardiopulmonary disease
Persons with immunodeficiency
Pregnant women
Healthcare personnel (HCP)
Persons who live with or care for persons at high risk
What are the two types of flu vaccine?
Inactivated Influenza Vaccine (IIV)
-flu shot
Live Attenuated Influenza Vaccine (LAIV)
-intranasal inhalation
What can cause viral pneumonia?
flu
respiratory syncytial virus (RSV)
Parainfluenza virus
adenovirus
coronavirus
How does viral pneumonia present clinically?
fever, chills, myalgias
non productive cough
may have rhonci on PE
CXR nondiagnostic
What are some causes of respiratory diseases?
Rhinovirus
the common cold
self limiting
Adenovirus
Respiratory illness (cold)
Viral pneumonia
diarrhea
conjuctivitis
Phayngitis
Mild, self-limiting
What are some common GI viruses?
Rotavirus (Children, fecal oral route-non inflammatory gastroenteritis. Vaccination against rotavirus has greatly reduced this number)
Norovirus (older children and adults)
Adenovirus & Coronavirus (infants and young children)
How are these GI viruses trasmitted?
Airborne droplets
Fecal-oral route
How do GI viruses clinically present?
NVD
How do you treat GI viruses?
Supportive (maybe an IV if pt is dehydrated)
What viruses spread with the arbovirus vector?
West nile virus
la crosse encephalitis
Zika Virus
What virus spreads with rhabdovirus?
rabies
How is west nile virus transmitted? Where is it most common?
Mosquito transmission
Africa, Asia, Middle east
How does west nile virus present clinically?
Mild illness- will go away on its own for 20% of those infected
dun dun dun
can lead to more severe neurologic illnesses
What are some mild ways in which west nile virus presents clinically?
Fever, HA
Body Aches
N/V/D
Rash
What are some serious ways in which west nile virus presents clinically?
high fever
severe HA/stiff neck
Confusion
Stupor/coma
seizures
Muscles weakness
Paralysis
How do you diagnose West Nile?
Serologic testing
(LP with CSF analysis)
How would you treat west nile virus?
supportive
How can you try to prevent west nile virus?
mosquito control
How is la crosse transmitted?
mosquito
How does la crosse present?
asymptomatic
acute febrile illness
-fever, HA, N/V/D, fatigue
Neuroinvasive disease (encephaliis)
-seizures, coma, paralysis
can lead to long term disability and death
Most severe disease occurs in pts <16
How is la crosse virus treated?
supportive
How is la cross virus prevented?
mosquito control
Who are some reservoirs of rabies virus?
bats
raccoons
skunks
foxes
woodchunks
coyotes
How can humans get rabies?
bite from infected animal
What is rabies pathophysiology?
travels from site of bite through nervous system
affects the brain (encephalitis)
-lead to death of untreated
How does rabies present?
flu-like illness
lasting 2-3 days
after 2-10 days: acute neurologic disease
Initially: anxiety, confusion, agitation
progresses: delirium, abnormal behavior, hallucinations, insomnia, hydrophobia, seizures
After what point in time is rabies survival very rare?
after presentation of neurologic disease
How do you treat prophylactically in rabies?
wash wound immediately
report to doctor/ED
-post exposure prophylaxis (PEP)
1 dose immune globulin
4 doses of rabies vaccine over a 14 day period
Given on day 1, 3, 7, and 14
current vaccines are given in arm
