CHAPTER 19: VIRAL DISEASES Flashcards
part of the virus that etermines serologic specificity, protects the nucleic acid from enzymatic degrada- tion in biologic environments, controls host specificity, and increases the efficiency of infection.
protein coat ( capsid)
few eroded follicular papules (resembling acne excoriée) to extensive lesions involving the whole beard area in men
caused by HSV -1 infection
Herpetic sycosis
Infection with HSV-1 is highly contagious to susceptible persons who wrestle with an infected individual with an active lesion.
Herpes gladiatorum
occur on the fingers or periungually
Lesions begin with tenderness and erythema, usually of the lateral nailfold or on the palm.
Deep-seated blisters develop 24–48 h after symptoms begin
Herpetic whitlow
causative agent of orolabial herpes?
HSV 1
causative agent of genital herpes?
HSV 2
MOT of genital herpes
Genital herpes is spread by skin-to-skin contact, usually during sexual activity.
describe the lesions of genital herpes
lesions are classic, grouped blisters on an erythematous base
tx for neonatal herpes
IV acyclovir for 14 days for SEM ( skin, eyes and/or mouth infection);
21 days for CNS and dessiminated dse
management for pregnant women with genital herpetic leisons or prodromal sx?
acyclovir 400 mg TID PO x 10 days ( except in the first month of gestation).
Caesarian section ( scalp electrode and vacuum assisted delivery is CI )
Infection with herpesvirus in patients with atopic dermatitis (AD) may result in spread of herpes simplex throughout the eczematous areas, called
eczema herpeticum (EH) or Kaposi varicelliform eruption (KVE).
3 clinical hallmarks of HSV infection
- pain
- active vesicular border
- scalloped periphery
what is the standard treatment for acyclovir-resistant herpes simplex
IV foscarnet
IV Cidofovir for Foscarnet resistant herpes simplex
most characteristic feature of HSV infection histologically
**multinucleated giant cells, ** molding together, forming a crude **jigsaw puzzle appearance. **
incubation period of VZV
10-21 days
MOT of VZV
respiratory route and less often by direct contact w/ the lesion
treatment of genital herpes
oral acyclovir, 200 mg five times or 400 mg three times daily; famciclovir, 250 mg three times daily; or valacyclovir, 1000 mg twice daily, all for 7–10 days.
when is Varicella most infetious?
infectious from 5 days BEFORE the eruption appears and are most infectious 1–2 days BEFORE the rash appears.
when does varicella ceases its infectivity?
Infectivity usually ceases 5–6 days after the erup- tion appears.
“teardrop” vesicles on an erythematous base
Varicella
most common neurologic com- plications of varicella
Cerebellar ataxia and encephalitis
what drug is commonly CI in varicella?
aspirin and other salicylates
risk of reye syndrome
treatment of varicella
acyclovir 20 mg/kg, maximum 800 mg per dose, four times daily for 5 days.
neonatal varicella can occur if the mother develops varicella when?
If the mother develops varicella between 5 days BEFORE and 2 days AFTER delivery
management of varicella in pregnant women
oral acyclovir, 800 mg five times daily for 7 days, except perhaps during the first month.
> /= 35 weeks of gestation or with increased risk of premature labor: admission and IV acyclovir, 10 mg/kg three times daily
VZIG is recommended in pregnant women when?
there is significant exposures within the first 72–96 h
(VZIG) should not be given once the pregnant woman has developed varicella.
Children immunized with live attenuated varicella vaccine may develop varicella of reduced severity on exposure to natural varicella. This has been called
modified varicella-like syndrome (MVLS)
VZV remains latent in ___
sensory dorsal root ganglion cells.
the dermatomes most frequently affected of VZV are:
the thoracic (55%), cranial (20%, with the trigeminal nerve being the most common single nerve involved), lumbar (15%), and sacral (5%).
what nerve is involve in herpes zoster ophthalmicus?
ophthalmic division of the fifth cranial nerve
Thoracic zoster may be associated with motor neuropathy of the abdominal muscles resulting in a bulge on the flank or abdomen, called a ____
“postherpetic pseudotumor.”
Ramsay Hunt syndrome results from involvement of the ______
facial and auditory nerves by VZV.
tx of herpes zoster
Valacyclovir, 1000 mg, and famciclovir, 500 mg, may be given three times daily.acyclovir, 800 mg five times daily
Three classes of medication are used as standard therapies to manage ZAP ( zoster-associated Pain) and PHN ( Postherpetic Neuralgia):
- tricyclic antidepressants (TCAs)
*Gabapentin and pregabalin - antiseizure medications
- phenylhydantoin, carbamaze- pine, and valproate;
- long-acting opiates
zostavax is a live attenuated vaccine for the prevention of Herpes Zoster. when should we stop taking antiviral meds?
Since it is a live virus vaccine, persons taking antiviral medications must stop them 24 hours before immunization and not take them for 14 days after immuniza- tion.
MOT of infectious mononucleosis
The virus is shed into the saliva, so contact with oral secretions is the most common route of transmission.
causative agent of Infectious mononucleosis
Epstein-Barr virus (EBV) / HHV 4
caused by HHV 4
fever (up to 40°C), headache, lymphadenopathy, splenomegaly, and pharyngitis (sore throat)
pinhead-sized petechiae, at the junction of the soft and hard palate (Forchheimer spots)
oral hairy leukoplakia
lab fx: absolute lymphocytosis of greater than 50% and monocytosis with abnormally large, “atypical” lymphocytes.
Epstein-Barr virus (EBV)
causative agent of Infectious mononucleosis
EBV /HHV4
caused by HHV 4
fever (up to 40°C), headache, lymphadenopathy, splenomegaly, and pharyngitis (sore throat)
pinhead-sized petechiae, at the junction of the soft and hard palate (Forchheimer spots)
oral hairy leukoplakia
lab fx: absolute lymphocytosis of greater than 50% and monocytosis with abnormally large, “atypical” lymphocytes.
Epstein-Barr virus (EBV)
causative agent of cytomegalovirus
HHV 5
Clinical manifestations in infants may include jaundice, hepatosplenomegaly, cerebral calci- fications, chorioretinitis, microcephaly, mental retardation, and deafness.
Purpuric lesions, showing extramedullary hematopoeisis called “blueberry muffin baby.”
An urticarial or morbilliform eruption or erythema nodosum in immunocompetent adults
Congenital cytomegalovirus (CMV)
tx of CMV
valganciclovir, foscarnet, or cidofovir
common cause of sudden, unexplained high fever in young children between 6 and 36 months of age.
may be accompanied by convulsions and lymphadenopathy.
at 4th day, fever drops then a morbilliform erythema of discrete, rose-colored macules appears
mucous membranes are spared
Roseola infantum
also called as 6th disease
Roseola infantum (exanthem subitum)
causative agent of Kaposi sarcoma
HHV 8
what is the most common cause of Gianotti-Crosti syndrome (GCS) worldwide?
EBV
affects children 6 months to 14 years of age
Proposed diagnostic criteria involve the following positive clinical fea- tures:
- Monomorphous, flat-topped, pink-brown papules or papulovesicles of 1–10 mm in diameter (Figs. 19-25 and 19-26)
- Any three or all four sites involved—face, buttocks, forearms, and extensor legs
- Symmetry
- Duration of at least 10 days
Negative clinical features include:
1. Extensive truncal lesions
2. Scaly lesions
Gianotti-Crosti syndrome (GCS)
main vector for monkeypox?
hosts for monkeypox?
vector: wild African rodents and monkeys.
accidental host: humans
MOT of monkeypox?
Direct contact with an infected animal or person appears to be required to acquire the infection,
are smooth-surfaced, firm, dome-shaped,
pearly papules, averaging 3–5 mm in diameter ;
central umbilication of the dome- shaped lesion.
in atopic children, it is a mild, eczematous eruption surrounding the individual lesions.
Henderson- Paterson bodies.
Molluscum contagiosum
tx of Molluscum contagiosum
Spontaneous resolution
Topical cantharidin, applied for 4–6 h
alternatives:
nicking the lesions with a blade to express the core (with or without comedo extractor), squeez- ing the lesion with a tissue forceps, light cryotherapy, applica- tion of trichloroacetic acid (TCA, 35–100%)
causative agent of Hand-foot-and-mouth disease (HFMD)?
coxsackievirus A16
tx for HFMD
Treatment is supportive,
in an enterovirus outbreak. Pediatrics 2013; 132:3149.
with oral or topical anesthetics.
note: use of oral glucocorticoids
associated with worse outcomes.
Also known as rubeola and morbilli
spread by respiratory droplets and has an incuba- tion period of 9–12 days.
Measles
fever, malaise, conjunctivitis, and prominent upper respiratory symptoms (nasal congestion, sneezing, coryza, cough). After 1–7 days, the exanthem appears, usually as macular or morbilliform lesions on the anterior scalp line and behind the ears.
Koplik spots
Lymphopenia, with a decreased WBC count.
Measles
commonly known as German measles, is caused by a togavirus and probably spreads by respiratory secretions. The incubation period is 12–23 days (usually 15–21).
Rubella
prodrome of 1–5 days consisting of fever, malaise, sore throat, painful LATERAL and UPWARD eye movement, headache, red eyes, runny nose, and adenopathy.
cephalocaudad axanthem apperance within 24 hrs and resolves on the 3rd day
Forchheimer’s sign
Posterior cervical, suboccipital, and postauricular lymphadenitis
blueberry muffin disease
Rubella or German measles
aka 5th disease
Erythema infectiosum
also known as phlebotomus fever and pappataci fever.
vector: Phlebotomus papatasii, is found in the Mediterranean area (Sicil
Sandfly fever
begins 2–15 days after the infectious mosquito bite.
high fevers accompanied by myalgias, head- ache, retro-orbital pain, and severe backache (breakbone fever)
elevated LFTs, thrombocytopenia, leukopenia.
eruption at 3-5 days of illness as fever defervesces
“islands of white in a sea of red”
dengue fever
how to do a tourniquet test?
taking BP, leaving the cuff inflated for 5 min. , waiting 2 min and counting petechiae.
(+) >10 petechiae per sq inch
phases of 5th dse (Erythema infectiosum)
three phases:
1st phase: slapped cheek appearance
2nd phase: After 1–4 days, erythematous macules and papules on the proximal extremities and later the trunk ( reticulate or lacy pattern)
3rd phase: recurring stage
reduced eruptions, only to recur after heat exposure
caused by Aedes mosquito
incubation period is 2–7 days
abrupt onset of high fever, joint pain and swelling for wks to months
Lymphopenia, thrombocytopenia, and elevated LFTs can be observed in the first week of the illness.
morbilliform exanthem
post-inflammatory hyperpigmentation
managed similar to burn patients
chikungunya virus infection
vector of Zika virus
Aedes aegypti and Aedes albopiticus
fever, rash joint pains, conjucnctivitis
petechiae on palate, gingival bleeding, diffuse papular eruption cephalocaudally
can be sexually transmitted ( persists in semen after months of infection)
causing birth defects : microcephaly and brain damage
zika virus
causative agent of external genital warts ?
anogenital dysplasia?
external genital warts:
HPV-6/11
anogenital dysplasia:
HPV-16/18.
elevated, rounded papules with a rough, grayish surface
tiny black dots may be visible, representing thrombosed, dilated capil- laries.
do not have dermatoglyphics (fingerprint folds)
verruca vulgaris or wart
caused by HPV types 3, 10, 28, and 41
common on swimmers and on the sun-exposed surfaces of the face and lower legs.
2–4 mm, flat-topped papules that are slightly ery- thematous or brown on pale skin and hyperpigmented on darker skin.
koebnerization, forming linear, slightly raised, papular lesions.
tx: topical retinoids
Flat warts (verruca plana)
lobulated papules that average 2–5 mm in size,
Cauliflower-like masses in perianal skin, vulva, and inguinal folds.
STD
Condylomata acuminata
also called HSIL (high-grade squamous intraepithelial lesion).
characterized by flat, often hyperpig- mented papules a few millimeters to several centimeters in diameter.
single or multiple lesions on penis, near the vulva, or perianally
caused by HPV-16, HPV-18
hx: Pigmentation of the epithelium and numerous mitoses, especially in meta- phase, are characteristic but not diagnostic of HPV-induced HSIL on the external genitalia.
may progress to squamous cell carcinoma (SCC).
bowenoid papulosis
rare, aggressive, wartlike growth that is a verrucous carcinoma.
caused by HPV-6.
MC on the glans or prepuce of an uncircumcised male;
regional lymphatic metastasis
tx: complete surgical excision
Giant condyloma acuminatum
(Buschke-Lowenstein tumor)
management of genital warts
- Podophyllin: warts on occluded or moist surfaces (mucosa or under the prepuce)
- Purified podophyllotoxin 0.5% solution or gel BID x 3 days
- Imiquimod
- Bichloracetic acid or TCA 35–85%
- Cryotherapy with liquid nitrogen
- Electrofulguration or electrocauterization
- CO2 laser
- 5-Fluorouracil 5% cream BID
uses the GLUT glucose transporter to enter cells
assoc with T-cell leukemia-lymphoma.
the most common skin conditions are dermatophytosis (30%), seborrheic dermatitis (25%), and xerosis/acquired ichthyosis (up to 80%).
Human T-lymphotropic virus
the patient is defined as having AIDS, when the Th cell counts is ___
Th cell </= 200
the patient is defined as having advanced AIDS, when the Th cell counts is ___
Th cell </= 50
some con- ditions may initially appear or be exacerbated by the sudden improvement of the immune status that occurs with eradica- tion of HIV viremia and with increase in Th-cell counts. This complex of manifestations is called _____
immune reconstitution inflammatory syndrome (IRIS)
IRIS occurs in 15–25% of HIV- infected persons started on HAART.
