OTC Antivirals Flashcards
What is varicella zoster? Epidemiology? 20:00
Highly infectious viral infection:
- Chickenpox in babies, children, young adults
- Shingles (herpes zoster) in adults
- Most common in children U10; over 90% of adults immune as they’ve had the virus before
- 13% will not develop sufficient immunity; liable to get it again
- After primary infection, virus is dormant in nerves; VZV can reactivate many years later
- Have had to had chicken pox to get shingles; secondary manifestation of VZV
What are the symptoms of VZV/chickenpox infection?
- Flu-like symptoms
- Fever
- Itchy rash of red
- Itchy spots that turn into fluid-filled blisters; fluid is v. infectious
- Crust over to from scabs, which shed
How is varicella zoster treated?
Neonates:
- Parenteral antiviral
Healthy children (1 month - 12 years):
- Symptomatic treatment (paracetamol, ibuprofen, topical agents e.g. calamine lotion)
- Stops child scratching; scar prevention (or cotton mitts)
Adolescents/adults:
- Treat w/antiviral (aciclovir) within 24 hours to reduce duration and severity (less severe primary infection)
How infectious is varicella zoster?
- Infectious af
- Infectious from 3-4 days before blisters form (fluid inside v. infectious)
- Thus patient must stay away from other people; particularly immunocompromised, high-dose steroids, pregnant women (1st trimester = risk)
What complications may arise from a pregnant lady being infected w/VZV?
- Maternal pneumonia risk
- 2% give birth to babies w/congenital varicella
- From 5 days before to 2 days after delivery; greatest risk of death to newborn
What is the difference between Varilrix and Varivax vaccines for VZV?
Varilrix:
- Deep SC injection into deltoid region or anterolateral thigh
Varivax:
- Injection either IM or deep SC
What is the criteria for VZV administration under PGD for pre exposure vaccination?
- Sero-negative HCPs at risk of developing chicken pox
- Lab staff that may be exposed to VZV in their course of work
- Contact of immunocompromised patients e.g. siblings of a child w/leukaemia
What is the criteria for VZV administration under PGD for post exposure prophylaxis?
- Unvaccinated HCPs w/o definite history of chicken pox or zoster and having a significant exposure to VZV
- ‘See Green Book’
Describe herpes zoster infection. How does it manifest?
- Shingles
- Infection of a nerve and the skin around it
- Cause by VZV dormant in nervous tissue post-chickenpox
- Reactivation by: old age, immunosuppressant therapy, HIV infection; risk & severity increases w/age
- Shingles can re-occur
- Possible to catch chickenpox from someone w/shingles
What are the symptoms of herpes zoster infection?
- Last 2-4 weeks
- Prodrome; then pain followed by rash
- Pain: localised, mild-severe, tender skin, lasts after rash has gone (infection of nerve)
»> 1 in 5 develop post-herpetic neuralgia (PHN); constant or intermittent burning, aching, throbbing, stabbing or shooting pain, allodynia, hyperalgesia
»> These can last for years, sometimes permanent.
What are some complications of herpes zoster infection?
- Ophthalmic shingles; when virus is reactivated in the trigeminal nerve (rash is right along the nerve)
- Ramsay-Hunt syndrome; inner-ear, deafness etc.
How is herpes zoster managed/treated?
1) Self care; keep rash clean, dry; covered w/loose clothing, cool compress, don’t share towels
2) Antivirals; aciclovir 900mg 5x day for 7-10 days (S/Es)
3) Analgesia; paracetamol, NSAId, opioids, TCAs, gabapentin, pregablin
What are the goals of treatment of herpes zoster management?
- Shorten the clinical course
- Provide analgesia
- Prevent complications
- Decrease incidence of PHN (post-herpetic neuralgia)
How effective is the shingles (herpes zoster) vaccine?
- Vaccination program for 70 and 79 y/o’s
- Vaccines reduce shingles incidence by 38%, PHN by 67%
- Zostavax; live attenuated vaccine that contains high antigen level of VZV
Describe herpes complex infection. What is it caused by?
Cold sores:
- HSV-1 (and HSV-2) cause small blisters around and on lips
- Initial infection asymptomatic, but highly contagious
- Start w/a tingling, itching or burning sensation around mouth. Small fluid-filled sores then appear; most commonly on edges of lower lip
- Once contracted, remains dormant mostly unless triggered
- Self-limiting; clears up within 7-10 days
How is herpes simplex treated? Complications?
Aciclovir topical cream:
- Antiviral
- Reduces symptoms and length of symptoms; apply before blister formation (as soon as tingling sensations begin)
Complications:
- Rare
- Dehydration
- Whitlows,
- Keratoconjunctivitis
- Skin infections
- Encephalitis
How does the HPV vaccine Cervarix differ from Gardasil?
Cervarix:
- Activity only against: Types 16, 18 (cause of most HPV-related cervical cancer)
Gardasil:
- Activity against Types 16, 18 as well as 6 and 11 (genital warts)
Who is the HPV vaccine offered to? What is it (Gardasil)?
- All girls in Year 8 in the UK (12/13 y/o’s; better immunological response)
- Non-infectious recombinant quadrivalent vaccine prepared from purified virus-like particles (VRP) of the major capsid (L1) of HPV Types 6, 11, 16, 18
- 6, 11 = 90% of genital warts
- 16, 18 = > 70% of cervical cancer cases in the UK
What are the barriers to HPV use?
- Anti-vaccination movement scaremongering
- > 80% of cervical cancer cases occur in developing countries; but HPV vaccines too expensive for too many
- Immunological response higher if given pre-pubescence
- Moral and ethical issues WRT vaccinations in prepubescents in some countries; worries it will encourage promiscuity
What are some examples of viral upper respiratory tract infections (URTIs)? What is transmission caused by?
- Caused by > 200 viruses
- Sinusitis, rhinitis, otitis media, pharyngitis, laryngitis, tracheitis, common cold, headcold etc.
- Transmission: hand-to-hand, hand-to-surface-to-hand
»> Most common infectious illness, main reason for missing work and school (biggest impact of economic productivity)
What are the symptoms of a common cold?
- Blocked (congested)/runny nose, facial pressure, sneezing
1) Clear discharge (mucus) at first from the nose; often becomes thick and yellow/green after 2-3 days
2) Difficulty sleeping due to a blocked nose, malaise, mildly high temperature
What are the main presenting symptoms in other URTIs aside from the common cold?
- Cough; usually main symptom
- Fever
- Headache
- Muscle aches and pains
- Fatigue
»> Cough can persist for 2-3 weeks
How are viral URTIs (e.g. common cold) managed?
- No effective cure or prevention
- Herd immunity, seasonal nature, stress, malnutrition
- Reduction in transmission: handwashing, tissues, not sharing utensils
- Symptomatic treatment; analgesics, fluids, smoking cessation
What is the efficacy of symptomatic treatments for URTIs?
- Decongestants
- Echinacea purpurea
- Zinc
- Vitamin C
»> Negligible evidence
What is the advice regarding cold remedies and children?
- Don’t use cold remedies in children U6 (MHRA 2009)
|»_space;> Excl. ibuprofen & paracetamol (okay for U6)
