Viral Infections

Question 1

describe the inflammatory response to viruses

Answer 1

• no PMN
• predominantly lymph mononuclear cells (lymphocytes, monocytes) and plasma cells
• antibody response may be protective (used for diagnosis)

Question 2

describe the clinical features of HSV-2

Answer 2

• mode of transmission: sexual/birth canal
• remain latent in sacral ganglia
• clinical features:
  
  • fever, malaise, recurrent vesicles which break open and produce raw painful ulcers on vulva, cervix, penis and perianal regions
  • +/- swollen lymph nodes

Question 3

describe the diagnosis and complications of HSV-2

Answer 3

• diagnosis:
  
  • HVS culture from vesicle fluir or ulcer
  • Tzanck preparation (scraping removal from base of ulcer show multinucleated squamous cells with eosinophilic intranuclear inclusions)
• complications:
  
  • meningitis in adults
  • encephalitis in neonates

Question 4

describe what is seen in the image

Answer 4

Question 5

describe what is seen in the image

Answer 5

Question 6

describe what is seen in the image

Answer 6

Question 7

describe the etiology of VZV - chickenpox

Answer 7

• etiology: VZV, transmission = airborne
• exposure leads to IgG antibody production which persists for life (immunity)
• cell mediated immunity also limit extent of infxn: VZV spread to sensory nerve, remains latent in dorsal root ganglion cells (DRG cells)

Question 8

describe the clinical features, lab studies, complications and prevention of VZV-chickenpox

Answer 8

• clinical features: vesicular skin rash, fever, headaches and malaise
• lab studies: viral culture, Tzanck smear from vesicles
• complications: pneumonia, herpes zoster
• prevention: vaccination

Question 9

describe what is seen in the image

Answer 9

Question 10

describe what is seen in the image

Answer 10

Question 11

describe what is seen in the image

Answer 11

Question 12

describe the etiology of CMV

Answer 12

• etiology: CMV
  
  • common cause of pneumonia in immunocompromised host
  • common opportunistic viral pathogen in AIDS (CD4<50) and transplant patients

Question 13

describe clinical features and diagnosis of a CMV infection

Answer 13

• clinical features:
  
  • lung: pneumonitis (mononuclear infiltrates, foci of necrosis and cytomegalic changes)
  • retinitis: blurring vision, double vision, cotton wool spots in both eyes
  • colitis: diarrhea
  • esophagitis: odynophagia, fever, retrosternal chest pain
• diagnosis: PCR assay of viral culture and tissue section
  
  • tissue section = enlarged alveolar macrophages/pneumocytes, contain eosinophilic intranuclear inclusions surrounded by a halo

Question 14

describe what is seen in the image

Answer 14

Question 15

describe the etiology and pathogenesis of rabies

Answer 15

• caused by Rabies virus (RNA)
• after contact (wound site) → virus binds to peripheral nerves → retrograde transport to DRG and spinal cord → brain (encephalitis)

Question 16

describe the clinical features and diagnosis of rabies

Answer 16

• clinical features
  
  • prodrome of 2-10 days
  • initially: malaise, headache, fevers and paresthesia at bite site
  • advanced infection: CNS excitability, paralysis, hypersalivation, hydrophobia and convulsion
• diagnosis:
  
  • viral culture from saliva, CSF or serum
  • autopsy

Question 17

describe what is seen in the image

Answer 17

Question 18

describe the etiology and pathogenesis measles (rubeola)

Answer 18

• etiology:
  
  • measles virus (RNA paramyxovirus)
• pathogenesis:
  
  • inhalation of droplets, virus enters lymphoid tissue and then enters blood
  • vaccination has decreased the incidence

Question 19

describe the clinical features and diagnosis of measles (rubeola)

Answer 19

• clinical features:
  
  • fever, coryza (rhinitis), conjunctivitis, koplik spots and cough and rash
• diagnosis:
  
  • serology for IgM or IgG titers, viral culture, virus isolation: measles giant cells

Question 20

list complications for measles (rubeola)

Answer 20

• complications:
  
  • pneumonia, otitis media, encephalitis

Question 21

describe what is seen in the image

Answer 21

Question 22

describe what is seen in the image

Answer 22

Question 23

describe what is seen in the image

Answer 23