Viral infections Flashcards
What are herpes viruses and what kinds are there?
DNA viruses
Herpes simplex virus = herpes genitalis HSV2, herpes labialis HSV1, herpetic keratoconjunctivitis HSV1 of eye)
Varicella-zoster virus (VZV) = 1) chicken box (varicella), 2) shingles (herpes zoster = latent varicella in dorsal root ganglia, unilateral neuropathic pain
cytomegalovirus (CMV) = asymptomatic in immuno-competent patient, cause disease in immunocompromised (retinitis, esophagitis, colitis)
What are the drugs used to treat herpes virus?
Foscarnet = nephrotoxic, not routine
Aciclovir = not well absorbed through skin or gut (poor + erratic)
Valciclovir (prodrug of aciclovir) and famciclovir = well absorbed orally, less frequent dosing compared to aciclovir
Ganciclovir (IV) = used in immunocompromised patients, dose dependent bone marrow suppression
Valganciclovir (prodrug of ganciclovir) (oral form of ganciclovir) = well absorbed orally, as effective as IV
What is a primary herpes illness?
Occurs in childhood, inflammation/herpes in the gums
Herpes typically will start where the first infection/exposure was
How is mild herpes recurrence treated?
Topical aciclovir
How is severe herpes recurrence treated?
Oral aciclovir (many doses)
Famciclovir, valciclovir (less doses than aciclovir)
What are the suppressive therapies for herpes virus?
oral aciclovir, valciclovir (6 months)
How are genital herpes treated?
Oral aciclovir, famciclovir, valciclovir
Lower dose for initial infection
Higher dose episodic treatment recurrence
same drugs for suppressive therapies = 6 months
Are children typically treated for varicella?
No, only neonates and adults (primarily) are treated due to inc risk of complications of varicella and severe disease
When should adults be treated for varicella?
treat within 36 hours after rash onset
Treat pregnant women within 72 hrs after rash onset
How do you treat varicella in adults?
oral aciclovir, famciclovir, valciclovir = if they havent had varicella before and are immunocompetent
How is varicella treated in immuno-compromised or complicated varicella cases?
IV aciclovir irrespective of rash duration
For neonates, preg, HIV, if varicella is in brain, liver, lung
What is shingles?
reactivation of herpes zoster later in life, presents as rash blisters w/ a dermatomal distribution on erythematous base
What is the antiviral treatment for shingles?
Immunocompetent (w/i 72 hrs) = famciclovir 8hrly, valaciclovir 8hrly, aciclovir 5*daily
Immunocompromised = admit to hospital, IV aciclovir
Will reduce = pain, duration of rash, viral shedding, ophthalmic complication
What are the types of herpes keratitis?
Epithelial keratitis
Stromal keratitis = corneal scarring and loss of vision
How is herpes keratitis treated?
Aciclovir eye ointment topically 5*/day
How is herpes zoster keratitis treated?
Topical is not effective
Oral for immunocompetent
IV for immunocompromised (acyclovir)
How is cytomegalovirus treated?
Immunocompetent = self-limiting (mono or hepatitis like syndrome)
Immunocompromised = valganciclovir, ganciclovir, foscarnet (immunocompetent), cidofovir (immunocompetent)
How is influenza treated?
Treat with neuraminidase inhibitors = oseltamivir or zanamivir
Antiviral therapy recommended for preg women after risk/benefit discussion = high risk of poor outcome
Give a general summary of herpes treatment
Treat as soon as possible
Herpes simplex = topical
Herpes zoster = systemic (oral, IV for high risk)
Acicolvir not ideal = freq dosing, erratically absorbed
Discuss Hep A
Contracted via = uncooked/contaminated food/water or direct contact w/ infected person
Self-limiting, no specific treatment
Discuss Hep B
Contracted via = bodily fluids, mother to child, unprotected sex
No cure (can be self-limiting otherwise chronic illness), low chance of chronic liver disease/cancer (except high chance for foetus)
Treatments (supress viral load, inactivate) = nucleotide/nucleoside analogues, pegylated interferon
Discuss Hep C
Contracted via = unsafe injection practice, infected blood/organ transfer, unprotected sex
Can survive outside body for long time, no natural immunity
Cause chronic infection, liver cirrhosis
What drugs are used to suppress Hep B viral load?
Entecavir, tenofovir
Can hep C be cured?
Yes, can be cured using directly acting antiviral drugs
Protease inhibitors, nucleotide polymerase inhibitors, non-nucleotide polymerase inhibitors, NS5A inhibitors
But no immunity after previous exposure
