Viral infections ug lecture 2003
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Transcript of Viral infections ug lecture 2003
VIRAL INFECTIONS
INTRODUCTION• Cutaneous manifestations – common in viral
infections
• Characterized by definite morphology and
distribution - clinically diagnosed
• Light microscope - visualized only when
aggregated into inclusion bodies
Intranuclear inclusion bodies are seen in the
herpes virus group and papilloma virus group
Intracytoplasmic inclusion bodies are seen in
the poxvirus group
COMMON VIRAL INFECTIONS OF SKIN DNA VIRUSES:
Papova virus - Human Papilloma Virus - Genital & Non-genital warts
Pox virus - Molluscum Contagiosum, small pox, milker’s
nodules, Orf
Herpes virus - Varicella Zoster Virus - Varicella, Herpes
Zoster; Herpes Simplex Virus I & I I- Herpes Simplex
RNA VIRUSES:
Picornavirus – Coxsackie virus – Hand foot mouth disease
Retrovirus - HIV
MANIFESTATIONS DUE TO VIREMIA AND HYPERSENSITIVITY
• Viral exanthems
First disease - Measles (Rubeola)
Third disease - Rubella (German Measles)
Fifth disease - Erythema Infectiousum
Sixth disease - Roseola Infantum
• Hypersensitivity reactions
Pityriasis rosea
Gianotti crosti syndrome
ETIOPATHOGENESIS
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)
HUMAN PAPILLOMA VIRUS INFECTION - WARTS Most common mucocutaneous viral infection
Incubation period: few weeks to about one year
Asymptomatic latent infection to warts to squamous
cell carcinoma
Direct or indirect contact (nail biters, shaving,
occupational, swimming pool); sexual transmission;
autoinoculation
Koebnerization – pseudo Koebner phenomenon
CLINICAL TYPESNon genital: Verruca vulgaris (Common warts) – HPV
2
Verruca Plana (Plane warts) - HPV 3, 10
Filiform
Digitate
Palmoplantar
Periungual
Genital: Condyloma Acuminata – HPV 6,11, 16,18
Bowenoid papulosis – HPV 16
Buschke-Lowenstein tumor – HPV 6,11
Epidermodysplasia verruciformis
HISTOPATHOLOGY
Hyperkeratosis
Papillomatosis
Acanthosis
Vacuolation in the stratum granulosum and stratum spinosum
- koilocytes
TREATMENT
Topical Keratolytics : Salicylic Acid, Urea, Wart solution (Lactic
acid/Salicylic Acid)
Chemical cautery: Podophyllin, TCA
Cryotherapy
Electrocautery
Radiosurgery
Laser therapy
Photodynamic Therapy
Others: Formalin soaks, Imiquimod, 5FU, retinoids, immunotherapy,
Bleomycin, Interferon
Systemic Immunomodulators: Levamisole, Cimetidine
SMALL POX
• Eradicated in 1977. Only humans, no carriers
• Eosinophilic inclusions - Guarnieri’s bodies
• IP=12-14 days
• Fever, chills, myalgia, rash 3-4 days later
• Firm papulovesicles, pustular in 10-12 day
• All in the same stage of evolution
• Edward Jenner - vaccinia virus
MOLLUSCUM CONTAGIOSUM
• MCV-1 to – 4 ; MCV 1 – children, MCV 4 – HIV infected
• Incubation period: 2 weeks to 6 weeks
Transmission: contact, fomites, sexual
Dome shaped, pearly white, discrete umbilicated papules - Face,
neck, trunk, peri-genitals (sexual transmission), eyelids (HIV).
Pseudo Koebner’s phenomenon
Giant Molluscum Contagiosum (1.5 cm) – HIV infected
Differential – cryptococccosis, histoplasmosis, penicilliosis
Tzanck – Henderson Patterson bodies
TREATMENT
Expression / Curettage
Chemical cautery, Electrodessication, Cryotherapy.
Topical: Imiquimod, KOH, Phenol, Cantharidine,
Cidofovir.
Systemic: Levamisole, Cimetidine, cidofovir
HERPES SIMPLEX VIRUS
HSV 1: Facial (above waist)
HSV 2: Genital (sexual)
Incubation Period : 3-7 days
First clinical episode - true primary infection or non primary
Persist in sensory ganglion - period of latency
Recurrent infection
CLINICAL FEATURES Grouped vesicles on erythematous base followed by
erosions and healing
Primary attack: severe with lymphadenopathy and systemic
complaints
Non primary : lower frequencies of systemic symptoms,
shorter duration of pain, fewer lesions, shorter healing time
Recurrences: mild with shortened clinical course, smaller
size of the vesicles, close grouping and absence of systemic
symptoms
Predisposing factors: trauma, sunburn, stress, coitus,
premenstrual, high grade fever, infections, surgery,
dermabrasion
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, recurrent
lumbosacral herpes, HSV infection in newborn
Complicated:
Eczema herpeticum, Disseminated HSV
Herpes Simplex Virus in HIV:
Chronic, recurrent, ulcer, eschar formation and
dissemination
Chronic HSV more than 1 month – AIDS defining
COMPLICATIONS
Radiculoneuropathy
Dissemination
Meningitis / encephalitis
Erythema multiforme
Eczema herpeticum
Ocular complications
INVESTIGATIONS
Tzanck smear : Multinucleated giant cells
Histopathology : Ballooning degeneration,
intraepithelial blisters, inclusion bodies
HSV antibody titre : IgG/IgM
Culture
Immunofluoroscence, PCR
Electron microscopy
TREATMENT
Symptomatic
Topical: Acyclovir, Penciclovir, Cidofovir
Systemic:
Resistant – foscarnet, cidofovir
Antiviral Primary
(10 days)
Recurrence
(5 days)
Suppressive
6months-1yr
Acyclovir 200mg
5times/day
400mg tid 400 mg bd
Valaciclovir 1gm bd 500mg bd 500-1000 mg bd
Famciclovir 250mg tid 125mg bd 250mg bd
VARICELLA ZOSTER VIRUS
Chicken pox and zoster (shingles)
Transmission: Droplet infection - nasopharynx
Varicella : primary viraemia
Zoster: Reactivation of residual latent virus in
the sensory nerve ganglion
VARICELLA - CLINICAL FEATURES
Incubation period: 2-3 weeks
2-10 years
Prodromal symptoms
Pleomorphic, centripetal distribution, dewdrops on rose petal
appearance
Vesicles, papulovesicles, crusting, haemorrhagic, umbilicated
lesions
COMPLICATIONS
Secondary infection
Encephalitis
Pneumonitis
Hepatitis
Varicella in HIV- Progressive, haemorrhagic, complicated
Chronic varicella- Hyperkeratotic lesions, Acute retinal
necrosis
Reye syndrome
Congenital varicella syndrome
TREATMENT
Symptomatic:
Rest, Antibiotics, Anti-inflammatory, Calamine lotion
Antivirals - Indicated in adult varicella; reduces severity, duration &
infectivity in childhood chicken pox
Acyclovir : 800 mg 5 times/day
Valcyclovir : 1gm tds - contraindicated in immunosuppresed
individuals - Thrombotic thrombocytopenic purpura and hemolytic
uremic syndrome
Prophylaxis:
Vaccine, Immunoglobulin, Acyclovir
HERPES ZOSTER
Reactivation of latent virus in the dorsal root ganglion of
sensory nerve
Older age group >50 years
Unilateral, dermatomal, grouped vesicles
Cranial (V, VII commonly), spinal (thoracic commonly)
Pre-herpetic, herpetic and post-herpetic neuralgia
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
HERPES ZOSTER : CRANIAL NERVE
INVOLVEMENT
VII nerve :
Ramsay Hunt syndrome:
Earache, vesicles on pinna, facial palsy
Hearing loss, vertigo and taste sensation impaired
COMPLICATIONS
Secondary infection
Post herpetic neuralgia
Scarring
Nerve Palsy
Encephalitis : in disseminated zoster
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
TREATMENT
Symptomatic
Antivirals:
Acyclovir 800mg x 5times/day
Famciclovir 500 mg tds
Valaciclovir 1gm tds
Duration : 1week in immunocompetent
2weeks in immunosuppressed
Steroids : in cranial nerve involvement
TREATMENT OF POST HERPETIC NEURALGIA
Steroids
Analgesics
Amitryptilline, Doxepine
Phenytoin, Carbamazapine, Sodium valproate
Gabapentine
Methylcobalamine
Topical EMLA cream
Topical capsaicin
Intralesional Steroids
HAND-FOOT-AND-MOUTH DISEASE
• Coxsackie virus A16, A5, A7, A9, and B 1, 2, 3; enterovirus 71
• IP - 4-6 days
• Vesicles painful erosions and ulcers on an erythematous base on buccal mucosa, tongue, palate, uvula.
• Gray-white vesiculopustules on palms, soles, dorsal or lateral surfaces of hands and feet., buttocks, thighs, and external genitalia
• Cervical and submandibular lymphadenopathy
• Encephalitis, aseptic meningitis, and myocarditis
• Hand hygiene
VIRAL EXANTHEMS
MEASLES (RUBEOLA/ MORBILLI)
• Preschool children; IP - 10-12 days
• 3 C’s —cough, coryza and conjunctivitis
• Koplik’s spots - blue white spots with a red halo on
buccal mucosa opposite the premolar teeth
• Maculopapular rash begins on the 4th day; face,
behind the ears trunk and extremities in 24-36
hrs maximum intensity in 3 days fades after 5-
10 days with desquamation
• Pneumonia, bronchitis, otitis media, gastroenteritis,
myocarditis, encephalitis
• Vitamin A supplementation; Vaccination at 9 -15
months
RUBELLA (GERMAN MEASLES/ 3 DAY MEASLES)
• > 15 years ; IP-12 to 25 days
• Posterior auricular Lymphadenopathy 4 to 7 days
before; maximal at onset; resolve in a week
• Forcheimer spots - petechiae of soft plate
• Maculopapular rash begins on neck or facetrunk
and extremities in a dayconfluent on face 2nd
day confluent on trunk, fades in face3rd day fully
fades
• Arthralgia, arthritis, encephalitis, thrombocytopenia
• Congenital rubella syndrome
• Vaccination at 15 months or older; 3 months
contraception
ERYTHEMA INFECTIOSUM
• 2-15 years
• 3 overlapping stages - facial erythema (slapped
cheek); Fades in 4 days 2 days laternet
pattern erythema – on extremities ; extends to
trunk and buttocks for 6-14 daysrecurrent
phase - fades and reappears in the next 2 to 3
weeks
• Papular-purpuric gloves and socks syndrome;
petechial exanthems
• Arthritis, transient aplastic crisis, chronic anemia
• In utero infection- hydrops fetalis, congenital
anemia
ROSEOLA INFANTUM EXANTHEM SUBITUM, “SUDDEN RASH”, 3 DAY FEVER
• 6 months- 2 years of age
• IP - 5-15 days
• Inappropriately well for the degree of fever
• Mild to moderate lymphadenopathy
• Seizures
• Rash begins as the fever subsides
• Pale-pink, almond-shaped confluent macules on
trunk and neckfade in a few hours to 2 days
without scaling or pigmentation
PAPULAR ACRODERMATITIS OF CHILDHOODGIANOTTI-CROSTI SYNDROME
• Hepatitis B (ayw), EBV (commonest), CMV, coxsackie, respiratory virus, parvoviruses, rotavirus, and HHV 6
• Vaccination –MMR, oral polio, DPT, hepatitis B.
• 2-6 yrs, males common
• Asymptomatic, symmetrical, edematous, erythematous, monomorphous, papules and papulovesicles, on face, extensors of upper and lower extremities
• Lymphadenopathy, hepatomegaly and anicteric hepatitis
• Self limited, lasts for 2-8 weeks.