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Learning ObjectivesViral Infections (continued)


Viral Infections

Herpes

 

 

 

 

Roseola
Roseola

1.  Roseola infantum (exanthem subitum)

    Etiology: Human herpesvirus 6 (HHV-6)
    Clinical features: Incubation 10-15 days, fever 39.5-40 C, lasts 3-5 days

    As temperature falls, rash appears

    Rash:

     

    Discrete rose-pink maculopapules, neck and trunk, fades 1-2 days
    Complications: Febrile convulsions not uncommon

     

 

Herpes simplex
Herpes simplex

Herpes simplex
Herpes simplex

Herpes simplex
Herpes simplex

Herpes simplex
Herpes simplex

Herpes simplex
Herpes simplex

Herpes simplex
Herpes simplex

2.  Herpes simplex

Etiology: Herpesvirus hominis (HSV 1,2)
Clinical features:
Primary Gingivostomatitis (usually HSV 1)
Incubation: 4-5 days
Fever, malaise, sore throat
Gums swollen, red
Rash: Vesicles followed by ulcers with a yellowish pseudomembrane
Recovery: Within 2 weeks.  Recurrent herpes labialis occurs frequently.

Herpes lesions arise in clusters in one area. 

Herpes genitalis (HSV 1, 2) Most often following sexual contact
Rash: Vesicles followed by superficial ulceration:  glans penis, vulva, vagina, or cervix
Recurrent infection: More frequent with HSV 2; on average 3-4 recurrences per year.

Vesicles smaller size, closely grouped on a red base, heals 7-10 days. 

Triggered by trauma, other infections

Complications: Keratoconjunctivitis, inoculation herpes simplex (herpetic Whitlow), eczema herpeticum, systemic infection with possible encephalitis


 

 

 

Varicella
Varicella

 

 

 

 

 

 

 

 

 

 

Herpes zoster
Herpes zoster

3.  Varicella (chickenpox) and Zoster (shingles)

Etiology:

Varicella-zoster virus (VZV)

Varicella

Clinical features:

Incubation 14-17 days, may have mild fever

Rash:

 

Papules, vesicles, pustules with red areolae (crusts)

Vesicles appear in crops over 2-4 days, most numerous on trunk

Complications:

Rare in healthy people aside from secondary infection

Pneumonia especially in adults, encephalitis, Reye's syndrome

Prevention:

a) Zoster immune globulin (ZIG) for immunosuppressed children must be given within 3 days of exposure

b) Prevention: Live attenuated vaccine for VZV, now HPB approved as of 1999

Zoster

Clinical features:

Pain is first manifestation, secondary to viral induced inflammation in sensory root ganglion

Rash:

 

Onset 1.4-3.2 days later

Papules, vesicles grouped, in a band along 1 or 2 dermatomes

Recovery:

2-4 weeks

Complications:

Motor involvement, ocular, post-herpetic neuralgia


 

 

Kaposi's sarcoma
Kaposi's sarcoma

4.  Kaposi's Sarcoma (Herpesvirus-Associated) HHV-8

  • DNA sequences from an agent, formed in Kaposi's sarcoma lesions in HIV-positive and HIV-negative patients have homology to herpesviruses
  • Because this herpesvirus-like nucleic acid is distinct from known herpesviruses, it indicates a new member of the herpesvirus family

 

  

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