Viral Diseases Flashcards
What is the pathophysiology of Herpes Simplex?
Virus infects through mucosal membranes or abraded skin. Latent infections harbored in neuronal cells: Trigeminal ganglia and Pre-sacral ganglia
What are clinical presentations of herpes simplex?
Dew-drop on rose petal. Primary infections: Gingivostomatitis and pharyngitis most frequent. Commonly seen in children and young adults. Fever, malaise, myalgias, inability to eat, irritability and cervical adenopathy lasts 3-14 days
Recurrence: Herpes labialis (“Cold Sores”)
Describe the urogenital lesions caused by HSV-1 or HSV2?
Vesicular lesions of external genitalia with pain, itching, dysuria, vagina and urethral discharge, tender inguinal lymph adenopathy
What complications can herpes simplex lead to?
Ocular disease. Neonatal and Congenital infections. Bells Palsy (CN7, facial). Encephalitis and recurrent Meningitis (most common cause of viral encephalitis in US). Herpetic whitlow
What is the best diagnostic method for herpes?
real-time HSV PCR assays are more sensitive method to confirm HSV infection in clinical specimens. particularly useful for the detection of asymptomatic HSV shedding
What is a Tzanck smear?
demonstrates the cytopathic effect of the virus (multinucleate giant cells), and can be performed on lesion scrapings from patients with active genital lesions. is only helpful if positive
What are the two distinct clinical presentations of Varicella-Zoster?
Primary infection: Chickenpox, transmission is likely by respiratory route. Recurrent infections: Herpes zoster, probably infects dorsal root ganglia during primary infection
What is the infectious period of Varicella-Zoster virus?
Incubation period: 10-21 days. Infected persons are infectious ~48 h before onset of vesicular rash and until all vesicles are crusted
What is the clinical presentation of chickenpox?
Rash, fever (100-103F) lasting 3-5 days, malaise
Skin lesions: Maculopapules, vesicles, and scabs in varying stages of development
What is the clinical presentation of herpes zoster (“shingles”)?
Unilateral vesicular eruptions which develop within a single dermatome (T3 to L3 most common). Often associated with severe pain
What diagnostic tests are used to confirm varicella-zoster?
complement fixation and virus neutralization in cell culture or fluorescent antibody test of smear of lesions
Describe the progression of the varicella-zoster viral infection vesicles?
thin-walled vesicle w/clear fluid forms on a red base. Vesicle becomes cloudy and depressed in the center with irregular border. A crust forms in the center and replaces the vesicle
How is varicella-zoster managed?
Vaccination. Primary disease: Prevent secondary infections. Recurrent infection: Acyclovir or Famcyclorvir. Analgesics
What are the clinical presentations of infectious mononucleosis (EBV)?
Fever/chills: 7-14 days. Lymphadenopathy rarely exceed 3 weeks duration (Posterior chain***). Severe pharyngitis with exudates for 5-7 days. HA, malaise, anorexia, soft palatal petechiae, rash (especially with administration of amoxicillin/PCN). Splenomegaly and mild hepatic tenderness
What are laboratory findings of infectious mononucleosis (EBV)?
Throat culture. Monospot. Heterophil antibodies. Atypical lymphocytosis in about 75%. EBV antibody titers directed at
What are possible complications of infectious mononucleosis?
Bacterial Strep pharyngitis, thrombocytopenia, neutropenia, splenic rupture, Bell’s palsy, Guillain-Barre syndrome, encephalitis
How is infectious mononucleosis treated?
supportive therapy, Tyelonal/NSAIDs, salt water gargles, rest, avoid contact sports 6-8wks
What is the clinical presentation of congenital CMV?
Ranges from inapparent infection to severe. Petechiae, hepatosplenomegaly, jaundice, Microcephaly, growth retardation, prematurity
What is the clinical presentation of perinatal CMV?
poor weight gain, adenopathy, rash, hepatitis, anemia and atypical lymphocytosis
What is the clinical presentation of CMV mononucleosis?
Heterophil Ab negative mononucleosis syndrome. Prolonged high fevers, profound fatigue and malaise. Myalgias, HA, & splenomegaly. Exudative phayngitis, cervical adenopathy, rubelliform rash are rare
What is the most important diagnostic study in the evaluation of suspected CMV?
viral culture from any body fluid or organ system.
What is the epidemiology of 5th disease (erythema infectiosum)?
Etiologic agent: Human Parvovirus B19. Respiratory tract is probably route of transmission