Herpes Viruses Flashcards
What viruses cause a maculopapular rash? Other differentials?
HHV6/HHV7
Parvovirus B19
Measles
Rubella
Bacterial: Scarlet fever - Group A strep Rheumatic fever Salphonella type - rose spots Lyme disease
Kawasaki disease
What viruses cause a vesicular/bullous/pustular rash? Other differentials?
Varicella sorter
Herpes simplex
Coxsackie A16
Impetigo
Boils
What viruses cause petechial/purpuric rashes? Other differentials?
Enteroviruses
Adenoviruses
Meningococcal/other bacterial sepsis
Infective endocarditis
Henoch Schonlein purpura Thrombocytopenia Vasculitis Malaria DIC
How does HSV enter the body and what do each HSV cause?
HSV enters through mucous membranes or skin.
Intense local mucosal damage
HSV1 is associated with lip and skin lesions
HSV2 is associated with genital lesions but both can cause both types of disease
How is HSV treated?
Aciclovir
Viral DNA polymerase inhibitor
How can HSV present in children?
Gingivostomatitis - vesicular lesions on the lips gyms and anterior surface of the tongue and hard palate which progress to painful ulceration and bleeding.
High fever and miserable child.
Eating and drinking are painful which may les to dehydration.
Cold sores - recurrent HSV lesions on gingival/lip margin
What is eczema herpeticum? What are herpetic whitlows?
Widespread vesicular lesions develop on eczematous skin - may be complicated by secondary bacterial infection
Painful erythematous oedematous white pustules on the site of broken skin typically on fingers - autoiuocation spread from gingivostomatitis and infected adults kissing children fingers.
What eye disease can HSV cause?
Blepharitis
Conjunctivitis
May extend to involve the cornea producing dendritic ulceration.
This can lead to corneal scarring and ultimately loss vision.
Urgent ophthalmic assessment with slit lamp corneal examination.
Describe chickenpox.
Spread, incubation, rash progression.
Varicella zoster infection
Spread by respiratory droplets, highly infectious during viral shedding (until day 5)
10-23 days incubation
Papules area of abnormal skin tissue that is less than 1 centimeter around
Vesicles fluid becomes trapped under the epidermis, creating bubble-like sac
Pustules
Crusts
Rash comes in crops for 3-5 days
Lesions may occur on the palate
Itchy and scratching
May result in permanent depigmented scar formation or secondary infection
What are complications of chickenpox
Secondary bacterial infection with staphylococci, group A streptococci or other organisms
Toxic shock or necrotising fasciitis,
Consider where there is new fever or persistent high fever after few days.
Encephalitis - VZV associated cerebellitis - occurs about a weak after rash onset - child is ataxic with cerebellar signs, resolves within a month
Purpura fulminans - vasculitis in skin and subcutaneous tissue - antiviral antibodies cross react and inactivate protein C or protein S inhibitory coagulation factors resulting in increased clotting risk
How is chickenpox treated?
Supportive
In immunocompromised - IV acyclovir initially
Humer varicella zoster immunoglobulin if immunocompromised and in contact with chickenpox
Describe shingles
Reactivation of latent VZV
Vesicular eruption in dermatomal distribution of sensory nerves, commonly in thoracic region.
Children unlike adults rarely suffer neuralgic pain with shingles.
Immunocompromised if recurrent or multidermatomal shingles
Describe Epstein Barr virus infection. Transmission Clinical features Diagnosis Treatment Avoid?
Infection mononucleosis - glandular fever
Can also cause Burkitt lymphoma in immunocompromised
Transmission by oral contact
Clinical features:
Fever
Malaise
Tonsillitis/pharyngitis - severe, limiting food intake
Lymphadenopathy - prominent cervical nodes
Petechiae on soft palapte
Spleno/hepatomeglay
Maculopapular rash
Jaundice
Diagnosis:
Atypical lymphocytes - large T cells on blood film
Positive monospot test - heterophile antibody positieve
Seroconversion with production of antibodies
Symptoms persist for 1-3months but resolve
Symptomatic treatment
Steroids when airway is compromised
Treat bacterial tonsillitis with penicillin
NOT ampicillin or amoxicillin as this can cause a rash in EBV infected children.
Describe cytomegalovirus infection Transmission Clinical features Diagnosis Treatment?
Saliva, genital secretions, breastmilk, blood products, organ transmplants, transplacentally
Mild infection in normal hosts
Pharyngitis, lymphadenopathy
Atypical lymphocytes but are heterophiles antibody negative
Treated with IV ganciclovir, oral valganciclovir or foscarnet in immunocompromsied
What can CMV infection cause in immunocompromised host?
Retinitis Pneumonitit Bone marrow failure Encephalitis Hepatitis Oesophagitis Enterocolotis
