Infections Flashcards
C - Herpes Simplex Virus 1
- an intensely painful infective ulcer on the fingertips is herpetic whitlow
- tingling sensation tends to precede herpes
- this is common in dentists as they are in contact with a lot of mouths
D - paracetamol & Calamine lotion
- treatment for chickenpox in children is aimed at symptomatic relief
- in adults, treatment is aimed at eradicating the virus
- oral acyclovir is given in adults
- oral valaciclovir is the treatment for shingles
B - this rash can only present unilaterally
- this is shingles, which has a dermatomal distribution
- it is caused by reactivation of VZV
- there is tingling in a dermatomal distribution
- treatment is with valaciclovir
- it is caused by a DNA virus
EBV
- it is NOT streptococcus pyogenes as strep throat presents with anterior cervical lymphadenopathy
- EBV presents with posterior cervical lymphadenopathy
E - Human herpesvirus 8
- this man has HIV, which predisposes him to Kaposi’s sarcoma
- this is caused by HHV8
What is the name of HHV-1?
How is it transmitted and what is the clinical presentation?
herpes simplex virus - 1 (HSV-1)
Transmission route:
- respiratory droplets / saliva
Clinical presentation:
- gingivostomatitis (mouth or gum swelling)
- keratoconjunctivitis (inflammation of cornea & conjunctiva)
- herpes labialis (cold sores)
- temporal lobe encephalitis
What is the name of HHV-2?
How is it transmitted and what is the clinical presentation?
herpes simplex virus 2 (HSV-2)
Transmission route:
- sexual contact
- perinatal
Clinical presentation:
- genital herpes
- neonatal herpes
What is the name of HHV-3?
How is it transmitted and what is the clinical presentation?
varicella zoster virus (VZV)
Transmission route:
- respiratory
Clinical presentation:
- chicken pox
- shingles
What is the name of HHV-4?
How is it transmitted and what is the clinical presentation?
Epstein-Barr virus (EBV)
Transmission route:
- saliva - known as the “kissing disease”
Clinical presentation:
- mononucleosis - associated with lymphomas & nasopharyngeal carcinoma
What is the name of HHV-5?
How is it transmitted and what is the clinical presentation?
cytomegalovirus (CMV)
Transmission route:
- congenital
- sexual
- saliva
Clinical presentation:
- mononucleosis in immunocompromised patients
What is the name of HHV-6 and HHV-7?
How is it transmitted and what is the clinical presentation?
HHV-6 & HHV-7
Transmission route:
- saliva
Clinical presentation:
- roseola infantum (high fever followed by a rash in infants)
What is the name of HHV-8?
How is it transmitted and what is the clinical presentation?
HHV-8
Transmission route:
- sexual contact
Clinical presentation:
- Kaposi’s sarcoma
What is the definition of herpes simplex virus?
How common is it?
this describes disease resulting from HSV1 or HSV2 infection
it is very common with 90% of adults seropositive for HSV1 by 30 years
it can be asymptomatic
What is the presentation of HSV-1 like?
herpes virus - think VESICULAR rash
- gingivostomatitis, cold sores (herpes labialis)
-
herpetic whitlow
- painful vesicular lesions on the hands / fingers
-
eczema herpeticum
- looks like eczema, but rash is vesicular
- herpes simplex meningitis, encephalitis
- systemic infection
- keratoconjunctivitis
What is the presentation of HSV2 like?
this presents as genital herpes, which is chronic and life-long
- flu-like prodrome
- vesicles / papules around the genitals & anus
- shallow ulcers
- urethral discharge
- dysuria
- fever and malaise
What is the aetiology for herpes simplex virus?
- the virus becomes dormant following primary infection
- it travels to the trigeminal / sacral root ganglia and stays there
- reactivation may occur in response to stress or immunosuppression (HIV)
What are the 2 phases involved in herpes simplex virus infection?
Latent phase:
- chronic infection where infectious virions are not produced
- the virus is within the trigeminal/sacral root ganglion
- there are no symptoms
Lytic phase:
- there is viral replication and transport of the virus to the skin
- this is active infection that produces symptoms
What investigations are carried out for herpes simplex virus?
What is involved in the management?
Investigations:
- usually a clinical diagnosis
- may consider viral culture / HSV PCR (not usually done)
Management:
- topical, oral or IV acyclovir depending on severity of presentation
What is the definition of varicella zoster infection?
- the primary infection is varicella (chickenpox)
- reactivation of the dormant virus in the dorsal root ganglia causes zoster (shingles)
this usually occurs due to stress and presents in a dermatomal distribution
What is the epidemiology of varicella zoster virus like?
- chickenpox has a peak incidence between 4 to 10 years
- shingles has a peak inidence of > 50 years
- around 90% of adults are VZV IgG positive
What is the presentation of chickenpox like?
- prodromal malaise
- mild pyrexia
- generalised pruritic vesicular rash
- this predominantly affects the face and trunk
- contagious from 48 hours before the rash and until all the vesicles have crusted over (within 7 - 10 days)
What is the presentation of shingles like?
- may occur due to stress
- there is tingling in a dermatomal distribution
- this is followed by painful skin lesions
- it is unilateral due to a dermatomal distribution (only in one of the trigeminal nerves)
- it can affect any dermatome, but is usually on the trunk
- recovery within 10 - 14 days
What are the investigations for varicella zoster virus?
How is the treatment different for chickenpox in adults and children?
- no investigations are performed - it is a clinical diagnosis
Children:
- supportive treatment to relieve the symptoms
- Calamine lotion to treat itching
- analgesia
- antihistamines
Adults:
- treatment is aimed at treating the virus, rather than the symptoms
- consider aciclovir, valaciclovir or famciclovir if within 24 hours of rash onset
- no treatment is given if the patient presents after 24 hours
What is the treatment for shingles?
- 1st line treatment involves valaciclovir or famciclovir
- 2nd line treatment involves aciclovir
if within 72 hours of appearance of the rash, given for 7 days
What is involved in the prevention of varicella zoster?
VZIG may be indicated in:
- immunosuppressed individuals
-
pregnant women exposed to varicella zoster
- this virus can have teratogenic effects
chickenpox vaccine is licensed in the UK, but no guidelines are available for appropriate use
What can shingles lead to in 15% of elderly patients?
postherpetic neuralgia
this is neuropathic (nerve) pain that occurs due to damage to a peripheral nerve caused by reactivation of VZV
nerve pain tends to be confined to a single dermatome