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Viral infections. Classification of Human Viruses. RNA Viruses : Retrovirus Togavirus Flavivirus Paramyxovirus Hepatitis A,C,E Picornavirus. DNA Viruses : Herpes Simplex Varicella Zoster Human Papilloma Poxvirus HHV (6,7,8) Epstein Barr Parvovirus Hepatitis B.

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Viral infections


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    Presentation Transcript
    1. Viral infections

    2. Classification of Human Viruses • RNA Viruses : • Retrovirus • Togavirus • Flavivirus • Paramyxovirus • Hepatitis A,C,E • Picornavirus • DNA Viruses : • Herpes Simplex • Varicella Zoster • Human Papilloma • Poxvirus • HHV (6,7,8) • Epstein Barr • Parvovirus • Hepatitis B

    3. Aetiopathogenesis • Cell lysis (Herpes) • Cell proliferation (Pox, HPV) • Carcinogenesis (Cervical Ca, Hepatoma) • Exanthemata - Viraemia, Type 3 hypersensitivity (Arthus) reaction, virus lodged in dermal capillaries and replicate in epidermis. • Persistent infection: Periods of latency and reactivation (HSV, VZV)

    4. Common Viral Infections of Skin • Human Papilloma Virus: Genital & Non-genital warts • Pox Virus : Molluscum Contagiosum • Varicella Zoster Virus: Varicella, Herpes Zoster • Herpes Simplex Virus I & I I: Herpes Simplex • Viral Exanthems

    5. Human Papilloma Virus: Aetiopathogenesis Human Papilloma Virus: DNA virus, 1-80 types Anogenital warts 6,11,16,18,31,33,51-59,70 • Incubation period: few weeks to about one year. • Transmission: direct or indirect contact (nail biters, shaving, occupational, swimming pool.) • Sexual transmission: genital/ perianal wart • Autoinoculation

    6. Clinical Types Non genital: Verruca vulgaris (Common warts) Verruca Plana (Plane warts) Filiform Digitate Palmoplantar Periungual Genital: Condyloma Acuminata

    7. Clinical features Verruca vulgaris: Commonest type of warts Children and young adults affected Asymptomatic, hyperkeratoticpapular lesions with warty excrescences Common Sites: Extremities, dorsae of hands & feet Koebner’s phenomenon present

    8. Clinical features Verruca plana: Juvenile/ flat warts Discrete flat skin colored or pigmented papules, coalesce Koebners phenomenon Sites: face, neck, extremities • Filiform: finger like projection • Digitate: Multiple finger like projections with common base Sites: head, face and neck

    9. Clinical features • Palmoplantar: Hyperkeratotic elevated or flat lesions, painful on lateral pressure Mosaic and Myrmecia Differential diagnosis: Corn, Callosity • Periungual: Commonly associated with palmoplantar warts, Invasion of nail bed. • Recalcitrant to Rx

    10. Genital Warts • Condyloma Acuminata: Protuberant moist ,cauliflower like growths Sites: frenulum, corona and glans in men and posterior fourchette in women Anogenital warts in children: sexual or non-sexual transmission • BowenoidPapulosis: Multiple, grouped, warty lesions on genitals, premalignant

    11. Complications • Secondary infection • Pregnancy related: Proliferative growth, obstruction of labour, laryngeal papillomas in child • Malignant change: Buschke-Lowenstein tumor Cervical intraepithelial neoplasia (HPV 16, 18)

    12. Investigations • Clinical diagnosis • Histology: Papillomatosis, acanthosis with inclusion bodies causing vacuolation in cells • Electron microscopy • DNA Hybridisation • Immunohistochemistry : Type of HPV

    13. Treatment • Topical Keratolytics : Salicylic Acid, Urea, Wart solution (Lactic acid/Salicylic Acid) Chemical cautery: Podophyllin, TCA Cryotherapy Electrocautery Radiosurgery Laser therapy Others: Imiquimod, 5FU, DNCB, Bleomycin, Interferon

    14. Treatment • Systemic Immnomodulators: Levamisole, Cimetidine Interferon Photodynamic Therapy

    15. MolluscumContagiosum • Pox Virus- MolluscumContagiosum virus • MCV 1 and MCV 2 • Incubation period: 2 weeks to 6 months • Transmission: contact, fomites, sexual. • Intracytoplasmic inclusion bodies

    16. Clinical features • Dome shaped, pearly white, discrete umbilicated papules. • Koebner’s phenomenon present • Sites: Face, neck, trunk, peri-genitals (more in sexual transmission), eyelids. • Giant MolluscumContagiosum / secondary infection.

    17. MolluscumContagiosum in HIV • Commonly on genitals, perianal region, eyelids • Refractory Mollscum on face • Disseminated lesions • D/D: Cryptococcosis, Histoplasmosis, Penicillinosis

    18. Treatment • Expression / Curettage • Chemical cautery, Electrodessication, Cryotherapy. • Topical: Imiquimod, KOH, Phenol, Cantharidine, Cidofovir. • Systemic: Levamisole, Cimetidine

    19. Varicella Zoster Virus • Chicken pox and shingles • Transmission: Droplet infection - nasopharynx • Varicella : primary viraemia • Zoster: Reactivation of residual latent virus in the sensory nerve ganglion

    20. Varicella - Clinical features • Incubation period: 2-3 weeks • Prodromal symptoms • Pleomorphic, centripetal distribution, dewdrops on rose petal appearance • Vesicles, papulovesicles, crusting, haemorrhagic, umbilicated lesions • Mucosal involvement

    21. Complications • Secondary infection • Encephalitis • Pneumonitis • Hepatitis • Varicella in HIV- Progressive, haemorrhagic, complicated • Chronic varicella- Hyperkeratotic lesions, Acute retinal necrosis

    22. Treatment • Symptomatic: Rest, Antibiotics, Anti-inflammatory, Calamine lotion • Acyclovir Dose: 800 mg 5 times/day Indicated in adult varicella; reduces severity, duration & infectivity in childhood chicken pox • Prophylaxis: Vaccine, Immunoglobulin, Acyclovir

    23. Herpes Zoster Clinical Features • Reactivation of latent virus in the dorsal root ganglion of sensory nerve • Older age group • Unilateral, dermatomal, grouped vesicles • Cranial (V, VII commonly), spinal (thoracic commonly) • Pre-herpetic, herpetic and post-herpetic neuralgia

    24. Herpes Zoster : Cranial nerve involvement V Nerve: • Ophthalmic division: Herpes Zoster Ophthalmicus Hutchinsons sign (vesicles on nose tip) Ocular complications: uveitis, keratitis, conjunctivitis, scleritis, ocular palsy • Maxillary division: uvula / tonsils • Mandibular division : tongue / buccal mucosa

    25. Herpes Zoster : Cranial nerve involvement VII nerve : Ramsay Hunt syndrome: • Earache, vesicles on pinna, facial palsy • Hearing loss, vertigo and taste sensation impaired

    26. Complications • Secondary infection • Post herpetic neuralgia • Scarring • Nerve Palsy • Encephalitis : in disseminated zoster

    27. Herpes Zoster in HIV • Younger patient • Severe pre, herpetic and post-herpetic neuralgia • Multi-dermatomal, cranial nerve involvement • Haemorrhagic, disseminated • Protracted course, verrucous lesions • Acute retinal necrosis

    28. Treatment • Symptomatic • Antivirals: Acyclovir 800mg x 5times/day Famciclovir 250-500 mg tds Valaciclovir 1gm tds Duration : 1week in immunocompetent 2weeks in immunosuppressed • Steroids : in cranial nerve involvement

    29. Treatment of post herpetic neuralgia • Steroids • Analgesics • Amitryptilline, Doxepine • Phenytoin, Carbamazapine, Sodium valproate • Gabapentine • Methylcobalamine • Topical EMLA cream • Topical capsaicin • Intralesional Steroids

    30. Herpes Simplex Virus • HSV 1: Facial (above waist) • HSV 2: Genital (sexual) • Incubation Period : 3-7 days • Primary infection • Persist in sensory ganglion - period of latency • Recurrent infection

    31. Clinical features • Grouped vesicles on erythematous base followed by erosions and healing • Primary attack: severe with lymphadenopathy and systemic complaints • Recurrences: mild with shortened clinical course • Predisposing factors: trauma, sunburn, stress, coitus, premenstrual, high grade fever, infections, surgery, dermabrasion

    32. Herpes Simplex- Clinical Types • Herpes Simplex Virus I : Herpes Labialis, Herpetic Gingivostomatitis, Herpetic whitlow, Herpetic gladiatorum, Herpes sycosis, Keratoconjunctivitis • Herpes Simplex Virus II: Herpes progenitalis, Herpetic vulvovaginitis • Complicated: Eczema herpeticum, Disseminated HSV • Herpes Simplex Virus in HIV: Chronic, recurrent, ulcer, eschar formation and dissemination

    33. Differential diagnosis • Aphthosis • Erythemamultiforme • Behcet’s syndrome • Pyodermas • Chancroid

    34. Complications • Radiculoneuropathy • Dissemination • Meningitis / encephalitis • Erythemamultiforme • Eczema herpeticum • Ocular complications

    35. Investigations • Tzanck smear : Multinucleated giant cells • Histopathology : Ballooning degeneration, intraepithelial blisters, inclusion bodies • HSV antibody titre : IgG/IgM • Culture • Immunofluoroscence, PCR • Electron microscopy

    36. Treatment • Symptomatic • Topical: Acyclovir, Penciclovir, Cidofovir • Systemic:

    37. Viral Exanthems • Macular: Rubella EBV(infectious mononucleosis) Human herpesvirus 6(roseola) Human herpesvirus 7 • Maculopapular : Togavirus Measles Human parvovirus B19 (erythemainfectiosum)

    38. Viral Exanthems • Maculopapular - vesicular : Coxsackie A (5, 9, 10,16) Echovirus (4, 9, 11) • Maculopapular - petechial: Togavirus (Chikungunya) Bunyavirushaemorrhagic fever (Lassa) • Urticarial: Coxsackie A9 and Hepatitis B

    39. Uncommon Viral Infections of the Skin : • Pox Viruses : Cowpox, Orf, Milker’s nodule • Epstein Barr Virus: Infectious Mononucleousis, OHL, GianottiCrosti, Lymphomas • Viral insect-borne and haemorrhagic fevers: (Toga, Flavi, Arena, Filo, Bunya) Chikungunya, Dengue, Kyasanur Forest Disease, Lassa • Picorna Viruses : Herpangina, hand, foot and mouth disease.

    40. Thank you