Viral Infections I Flashcards
what are the 3 virus classifications
- DNA viruses
- Invade and replicate in host cell nucleus - Single stranded RNA viruses
- Invade and replicate in host cytoplasm - Retroviruses
- Use reverse transcription to create a DNA copy of their RNA genome and insert it into the host cell - becomes a part of the host RNA
steps of viral infection
- Virus attaches to host cell
- Viral DNA or RNA then enters the host cell and replicates inside host cell
- Creates viral particles inside the cell
- The host cell typically dies - releasing new viruses that move on to infect other host cells.
how can viruses be transmitted
- Respiratory secretions (airborne droplets)
- Enteric secretions (fecal-oral route)
- Sexual contact (direct mucosal contact, semen/body fluids)
- Blood (contaminated needles and blood products)
7 types of human herpesviruses
- 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
- Roseola infantum - Human Herpesvirus (HHV) 8
- Kaposi Sarcoma - Only in AIDS patients
which HSV affects the oral region
HSV1
which HSV affects the genitalia
HSV2
risk factors of HSV
- Female
- History of STDs
- Multiple sexual partners
- Contact with sex workers
- WSW
how is HSV transmitted
- Skin to skin contact
- Fluid from vesicle releases HSV
- Can transmit infection without actual presence of vesicles - Once infected - lifelong
- May lay dormant for months or years
- Vesicles forming crusts and moist ulcers
- Singular or grouped
- Lips (upper), nares, mouth - Herpetic Whitlow
- Digital vesicular lesions
HSV1
Multiple vesicles forming crusts and ulcers
- Multiple, grouped, painful vesicles
- May have pain or itching before appearance of lesions
- External genitalia, vaginal canal, perianal
HSV2
HSV1 has associated symptoms with ?
such as…
oral infection
- Pain, burning, tingling of skin
- Pain with eating (if inside mouth)
- Swollen lymph nodes
- Low grade fever
when is the severity of HSV worst and longer?
initial outbreak
which HSV has associated symptoms of genital infection
- Pain, burning, tingling of skin
- Dysuria
- Cervicitis
- Urinary retention
- Swollen lymph nodes
- Fever, body ache
HSV2
after a HSV infection, what happens to the virus?
- remains dormant in nerve ganglia
- Periodic symptomatic reactivations = “flares”
triggers of HSV flares
- Febrile illness
- Hormonal changes (pregnancy, menstrual cycle)
- Physical or emotional stress
- Overexposure to sunlight
pt presenting with:
Initially present with blepharitis
Impaired visual acuity - can lead to blindness
Pain, sensation of something in eye, photophobia, unilateral
HSV Keratoconjunctivitis
transmission of HSV Keratoconjunctivitis
- Direct inoculation
- Neonates - Trigeminal nerve spread
what HSV is usually only seen in immunocompromised
- HSV Encephalitis
- Disseminated (Pneumonia)
- Esophagitis
- Proctitis (inflammation of the lining of the rectum)
how do you diagnose HSV
- Characteristic clinical appearance
-
Cx
- Vesicular fluid
- Scrapings of crust/ulcer -
PCR
- CSF for HSV encephalitis -
Tzanck smear: Presence of multinucleated giant cells - positive for herpetic infection
- Can also be positive with Varicella; does not tell you if HSV 1 or 2
how to diagnose HSV Keratoconjunctivitis
Diagnose with appearance of dendritic lesions on fluorescein stain and slit-lamp examination
(Immediate referral to Ophthalmologist)
tx for HSV
- Outbreaks self-limiting - 10 - 20 days with initial outbreak
- 5 - 10 days with recurrences - No cure
- Antivirals (oral & topical)
- Shorten duration
- Lessen severity
- Start at first sign of outbreak
- Patients with frequent recurrences can take as prophylaxis
Symptomatic Relief for HSV (topical)
- Topical anesthetics (Gingivostomatitis)
- dyclonine (Sucrets)
- benzocaine (Anbesol)
- Rx viscous lidocaine rinse (Magic Mouthwash)
tx for Secondary Bacterial Infections of HSV
Topical antibiotics
- mupirocin
- bacitracin
antivirals for HSV
- acyclovir (Zovirax)
- famciclovir (Famvir)
- valacyclovir (Valtrex)
all available in oral - topicals
- penciclovir (Denavir)
- docosanol (Abreva) - OTC
which HSV antiviral is available in oral, liquid, IV, and topical
acyclovir
tx for HSV keratitis
trifluridine (Viroptic)
MOA of HSV antivirals
Inhibit herpes viral DNA synthesis and replication
which HSV antivirals are prodrugs - converted to active form in GI tract
valacyclovir (Valtrex) and famciclovir (Famvir)
which HSV antiviral is metabolized in the liver
acyclovir
HSV antivirals should be used cautiously with ?
renal patients
SE of HSV antivirals
- Most Common
- GI symptoms
- HA, dizziness, malaise
- Arthralgia - Most Serious
- Leukopenia, thrombocytopenia
- Neurologic manifestations - hallucinations, psychosis, seizures
HSV antivirals can cause an elevation in what lab values?
BUN/Cr - Check at baseline and monitor if prolonged use
which HSV antiviral is only used if severe strain resistant to acyclovir
MC use for CMV infections in AIDS patients
foscarnet (Foscavir)
which HSV antivirals is only used for CMV infections in immunocompromised (HIV) patients
- ganciclovir (Cytovene)
- valganciclovir (Valcyte)
what HSV antivirals have a BBW of seizures, renal impairment causing toxicity - hematologic abnormalities, possible carcinogenic
- foscarnet (Foscavir)
- ganciclovir (Cytovene)
- valganciclovir (Valcyte)
tx for Primary & Recurrent HSV genital infection
- antivirals
- Oral acyclovir (Zovirax) 400 mg TID
- valacyclovir (Valtrex) 500 - 1000 mg BID
- famciclovir (Famvir) 250 mg TID - Treat initial episode for 7-10 days
- Recurrences often reduced to 3-5 days - Treatment for initial episode should begin 48 hrs of onset (no more than 72hrs)
- Recurrences should initiate treatment at first sx onset (within 24 hrs)
tx for Primary & Recurrent HSV oral infection (herpes labialis)
- Oral antivirals (same as for genital herpes)
- Topical 1% hydrocortisone 5% acyclovir cream (Zovirax ointment), penciclovir (Denavir)
- OTC docosanol (Abreva)
Recurrent HSV prophylaxis tx
acyclovir 400 mg BID daily
valacyclovir 500 mg QD daily
famciclovir 250 mg BID daily
recurrent Keratitis tx
- Topical trifluridine (Viroptic) ophthalmic drops
- Oral acyclovir
tx for HSV Disseminated/Neonatal Disease
IV acyclovir
prevention for HSV
- Barrier methods during sexual activity
- C-section for women with active genital lesions
- Sunscreen can reduce the occurrence of herpes labialis
Varicella zoster virus (VZV) causes?
Herpes Zoster (Shingles)
the initial infection of Varicella zoster virus (VZV) causes?
chickenpox
the risk of Herpes Zoster (Shingles) increases with age ? and what kind of pt?
60+
immunocompromised
- macules -> papules -> vesicles -> crusts
- Lesion sits atop an erythematous base “dew drop on rose petal”
- Severe pain commonly precedes rash
Herpes Zoster (Shingles)
- Follows dermatome
- Typically a single, unilateral dermatome - MC thorax and lumbar regions
Herpes Zoster (Shingles)
shingles can have trigeminal nerve involvement which could result with:
- Herpes Zoster Ophthalmicus - most serious
- Lesions in corner of eye and side of nose (Hutchinson’s sign)
- Can cause blindness with severe eye involvement
complications with shingles
- Post-herpetic neuralgia
- 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
tx goals for shingles
- Reduce duration
- Lessen severity of symptoms
- Reduce risk of post-herpetic neuralgia
antivirals for shingles
- acyclovir (Zovirax)
- valacyclovir (Valtrex)
- famciclovir (Famvir)
tx should be started within 72 hours of onset of symptoms
tx for Herpes Zoster Ophthalmicus
- Admit for IV acyclovir
- Topical steroids
emergency!
tx for post-herpetic neuralgia
- Pain management
- Opioids
- TCA’s
- gabapentin (Neurontin)
prevention for shingles
- Recombinant vaccine “zoster vaccine” (RZV or Shingrix)
+ 50< years of age
- 2 vaccines required 2-6 months apart whether or not they received Zostavax
+ immunosuppressed or immunodeficient 19< years of age should receive 2 doses of RZV
+ lasts at least 4 years after vaccination
To prevent Post-Herpetic Neuralgia
Human herpesvirus 4
Causative agent for Infectious Mononucleosis
Epstein-Barr Virus
transmission of EBV
- Saliva, blood products
- Mono = “Kissing Disease”
posterior cervical LN
Splenomegaly (50% of pt)
Palatal petechiae
Maculopapular rash (20% of pt)
EBV
pt with EBV can experience a worse Maculopapular rash bc?
if given ampicillin - rash seen in >90%
diagnosis of EBV
- Mononucleosis spot test (Monospot)
- Heterophile agglutination (HA) antibody test - Blood smear
- Atypical large lymphocytes - CBC
- Leukopenia, lymphocytosis - EBV antibodies
if you’re testing for EBV antibodies, which one comes up for an acute infection
- IgM antibodies
- IgG antibodies to EBV persist for life
complications from EBV
- Splenomegaly/splenic rupture
- rare
- Avoid strenuous activity / contact sports - Hepatitis
- Watch for s/sx: jaundice, N/V
- Monitor LFTs - CNS involvement - infrequent
tx for EBV
- Supportive
- Fluids
- Antipyretics - hospital
- severe splenomegaly
- hepatitis
- CNS involvement
- severe thrombocytopenia
Antivirals NOT indicated
Antibiotics NOT indicated
someone with EBV their fever and sore throat should resolve when?
in 10 days
EBV
LAN, splenomegaly should resolve when?
in 4wks
associated disorders with EBV
- Burkitt Lymphoma
- B-cell malignancies in immunocompromised persons
- Nasopharyngeal carcinomas
how can Cytomegalovirus (CMV) be transmitted?
blood, body fluids, and transplacentally
unless youre immunocompromised, most ppl with Cytomegalovirus are ___
asymptomatic
60-90% population - Asymptomatic latent infection
3 clinical syndromes of Cytomegalovirus - CMV
presentations?
-
CMV inclusion disease - newborns
- Hepatitis, mental retardation, hearing loss
- Stillbirth -
Acute viral syndrome - immunocompetent persons
- Fever, malaise, arthralgias - Mono-but without the pharyngitis -
CMV disease - immunocompromised persons (HIV)
- CMV Retinitis
- GI (gastritis/colitis), Respiratory (pneumonitis), Neurologic (encephalitis) CMV
diagnostic testing for CMV
serologic testing
tx for CMV
- ganciclovir (Zirgan) or valganciclovir (Valcyte)
- foscarnet (Foscavir)
ONLY for serious illnesses (CMV retinitis, encephalitis, etc)
Condyloma acuminata is from what HPV strains
HPV 6 and 11
HPV 16 and 18 is responsible for 70% of this disease
cervical cancer
Scaly, raised, skin colored to pearly lesions
Often occur in clusters
May be pedunculated
May have associated pruritus, burning, bleeding, or pain
Condyloma acuminata
(genital warts)
how do you diagnose Condyloma acuminata
- Clinical
- Determine extent of involvement:
- Anoscopy, speculum exam, colposcopy
no need for bx
tx for Condyloma acuminata
- Chemical destruction
- Podophyllin/Podofilox
- Imiquimod (Aldara) - Cryotherapy (office)
- Systemic treatment
- Interferon - Laser surgery
OR - Surgical excision
how does HPV turn into cancer?
- HPV virus infection - sexually transmitted
- Persistence of HPV infection
- Progression of normal epithelial cells to precancerous cells
- Development of carcinoma
besides cervical cancer, what other cancers can HPV cause?
oropharyngeal, vulvar, and penile cancer
how do you diagnose Cervical/ Anogenital Cancer
bx
found on routine pap smear
tx for cervical cancer
- Laser ablation
- “Cone biopsy”/LEEP
- Surgery
prevention for cervical cancer
- Vaccines
- Gardasil - protects against HPV strains 6, 11, 16, 18, 31, 33, 45, 52, and 58
- administered 9-26(F)/21(M), then 45
Goal for vax: start before female/male is sexually active
how do you describe a virus that shows slow, gradual change
Antigenic drift
how do you describe a virus that shows sudden change
antigenic shift
Little to no immunity/responsible for pandemics
what are the other strains of influenza
- “Swine flu”
* H1N1
* H3N2v - “Bird flu”
* H5N1
- China, Asia, Middle East
- “Highly pathogenic” - 60% mortality rate
* H7N9
- China only
if a pt presents with
- Sudden onset fever, chills, headache, myalgia, malaise
- Non-productive cough, sore throat, nasal discharge
- Physical examination is typically unremarkable
what is the infection?
influenza
complications with influenza
- Secondary bacterial infections - pneumonia, sinusitis
- Rhabdomyolysis, myositis
- CNS involvement - encephalitis, aseptic meningitis
- Cardiac complications
diagnostic testing with influenza
- Rapid Influenza Diagnostic Test (RIDTs)
- NP swab, nasal aspirate
- Detects both A and B within several 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
tx for influenza
- Supportive Care
- Antipyretics
- Fluids
- Analgesics - Antivirals
- Neuraminidase Inhibitors - oseltamivir (Tamiflu), zanamivir (Relenza), peramivir (Rapivab)
- NMDA Receptor Antagonists - amantadine, rimantadine
which influenza antiviral class is the FDA approved to treat seasonal influenza, covering both influenza A and B
Neuraminidase Inhibitors
which influenza antiviral class cover influenza A only
NMDA Receptor Antagonists
what influenza antiviral is used for tx only
peramivir (Rapivab)
everything else can be used for treatment and prophylaxis
when should influenza antivirals be started?
within 48 hrs of symptoms
dosage for oseltamivir (Tamiflu)
75 mg po BID x 5 days
- Tx = all ages
- prophylaxis = 3 months and older only
pt with a lung disorder presenting with influenza should not be given what antiviral?
zanamivir (Relenza)
SE of Neuraminidase Inhibitors
- N/V/D, HA (MC)
- Most Serious
- Bronchospasm with Zanamivir (Relenza)
- Can cause behavioral disturbances (rare)
prevention for influenza
- vax
- Routine annual vaccinations of all persons aged 6 months and older
- Should receive vaccine in October
flu vaccination particularly important for who?
- Young children
- Persons >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
types of flu vaccines
- Inactivated Influenza Vaccine (IIV)
- “flu shot” - Live Attenuated Influenza Vaccine (LAIV)
- Intranasal inhalation
what are the causative agents in adults for viral pneumonia
- Influenza
- Respiratory syncytial virus (RSV)
- Also causes pneumonia and bronchiolitis in children - Parainfluenza virus
- Also causes laryngotracheobronchitis (Croup) in children - Adenovirus
- Also a cause of the “common cold” - Coronaviruses
if a pt presents with:
1. Fever, chills, myalgias
2. Nonproductive cough
3. rhonchi on PE
4. CXR nondiagnostic
what could be their diagnosis?
viral pneumonia
tx for viral pneumonia
- supportive
- fluids
- antipyretics - deep suctioning - for rhonchi
pathophys of rabies
- Travels from site of bite through nervous system
- Affects the brain = Encephalitis
- Lead to death of untreated
clinical presentation of rabies
- Initial presentation: flu-like illness
- Lasts for 2-3 days - After 2-10 days: acute neurologic disease
- Initially: anxiety, confusion, agitation
- Progresses: delirium, abnormal behavior, hallucinations, insomnia
Once a person exhibits signs of neurologic disease - survival is rare
management for 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
what abx should be avoided for EBV
ampicillin, amoxicillin
