1 / 40

Viral infections

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.

nemo
Télécharger la présentation

Viral infections

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

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

More Related