viral infection

Viral infections

Objectives:
1- Describe the clinical features and treatment of herpes simplex, chicken pox and viral warts
2- differentiate genital herpes from other causes of genital ulcers.
3- describe the clinical features and lines of treatment of pox virus infections.
4- describe the clinical features of measles and rubella

Herpes simplex

Cause: herpes virus hominis, DNA virus.
HSV I: mostly oral, transmitted by saliva
HSV II: mostly genital transmitted by sex
Virus entry primary infection latent infection recurrent attacks

Clinical features

*Primary type I: usually asymptomatic, children.
Symptomatic gingivostomatitis-vesicles
and erosions- 2 weeks
keratitis
whitlow
*Primary type II: genital vesicles and painful erosions



Recurrent attacks (type I):
Herpes labilais or cold sore: Recurrent vesicles
pustules erosions in the lips and near skin
Ppt. factors: sunlight, menstruation, viral and bacterial infections.
recurrent attack usually last 1 week.

Recurrent type II:

*Recurrent genital ulcers affecting the penis, vulva, vagina, anus.
*type II recur more frequent than type I
* It is a common STD
*represent a bad stigma with guilt feeling because of its persistence for many years.

complications

Meningitis
Encephalitis
Disseminated inf.
Secondary impetigo
Corneal ulceration

Treatment

Primary:
Mild cases: rest, symptomatic, acyclovir 200mg 5 times daily for 10 days.
Disseminated inf. In immunocompromised : intravenous acyclovir 5-10mg/ kg 8 hourly

recurrent attacks: suppressive therapy

Acyclovir 400mg twice daily

Acyclovir not eradicate the HSV from the ganglia, but decrease the recurrence

Varicella

V-Z virus.
Transmission: direct contact and respiratory
Prodromal symptoms: flu like
Pink papules vesicles pustules crusted erosions
Centripetal distribution
Treatment: symptomatic, acyclovir for adults, severe cases and immunocompromised


Herpes zoster
Caused by reactivation of V-Z virus acquired from previous chicken pox inf.
V-Z virus latent in the cranial or dorsal root ganglia, its reactivation herpes zoster at the dermatome of corresponding nerve
Usually its risk increase with age and low immunity

Clinical features

Unilateral dermatomal pain for 3-5 days
vesicles ulcerations.
Last 2-6 weeks according to the age
Sites of involvement: thoracic, cervical, trigeminal, lumbosacral

Complications

Secondary bact. Inf.
Corneal ulceration in ophthalmic zoster
Motor nerve involvement
Post herpetic neuralgia

Treatment

Mild cases: rest, symptomatic
Severe cases, ophthalmic zoster, low immunity
acyclovir within 2-3 days
analgesics, antidepressants


Viral warts
Cause: HPV, more than 60 subtypes
Transmission: direct contact and sex.
Usually affects young people
Immune deficiency extensive warts
Type 16 and 18 cause cervical ca.

Clinical features

Common warts ( verruca vulgaris): single or multiple papules with rough surface.
Usually affect the hands, but can appear anywhere.
Plantar warts: rough slightly raised papules.
Plane warts: slightly raised skin colored- grey- pink smooth papules. Face and hands

Anogenital warts (condylomata acuminata)

Affects skin and m.m. of the genital area.
Papillomatous or cauliflower lesions
D.Dx:
Condylomata lata: flat papules, other features of secondary syphilis.

Treatment

Local therapy:
*Keratolytics: 12-20% salicylic acid
* caustic agents: TCA for genital warts
* cytotoxics: 5-FU for plane warts.
podophylline for genital warts
* Surgical: curretage, electrocautery, cryotherapy
* immunomodulators: imiquimod for plane and genital
warts
* Retinoic acid: for plane warts


Systemic therapy
For extensive warts
Zinc sulfate, BCG vaccine, retinoids

Pox virus infections

Molluscum contagiosum
* Pox virus, transmitted by direct contact and sex
* Clinical features: I.P. 2-6 weeks
Shiny white or pink papule with central punctum in some cases.
* usually disease of children, especially affects the face.
* In adults involvement of the genital area indicates STD.

treatment

Squeezing, curretage, cryotherapy, cautery, phenol puncture, retinoic acid

Orf








orf
Caused by parapox v.
Transmitted from sheep.
I.P. 1 week
Firm papule pustular nodule
Clear in about 6 weeks spontaneously.
No treatment required.

Measles

Paramyxovirus, droplet transmission.
I.P. 10 days
Catarrhal stage:2 days of fever, running nose, red eyes, then photophobia and koplik’s spots
Days 3-4 maculopapular rash covering the body in 3 days
Days 6-7 days fever and rash subside fever and rash.

complications

Pneumonia, keratitis, otitis media, encephalitis, weight loss

Treatment

Symptomatic, antibiotics for secondary bact. Inf.


Rubella (German measles)
Caused by toga virus, droplet inf.
I.P. 18 days.
Less severe than measles, trivial in children, more severe in adults.
Prodromal symptoms with suboccipital LAP
Fine maculopapular rash covering the body in one day and disappear in the 3rd day.

AIDS

Caused by HIV, which target the CD4 T cells
Skin manifestations of AIDS
*Tumors: kaposi sarcoma, extensive with systemic involvement
* dermatitis: seborrheic derm.
* infections: opportunistic inf. ex candidiasis, severe HSV and HZV.


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Summary

Primary herpetic gingivostomatitis…. Children
Recurrent orolabial herpes… children and adults.
Recurrent genital herpes ….guilt feeling.
Varicella: polymorphic rash, centripetal
H. zoster: severity is age dependent.
viral warts: verrucous surface, usu. Self limited

Measles: toxic, maculopapular rash and fever

Rubella: milder than measles
Molluscum contagiosum: Easily treated.
Orf: sheep. باجة