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BDS4 Oral Medicine > Oral Viral Infections > Flashcards

Oral Viral Infections Flashcards

1
Q

What are the key features of viruses?

A
  • Incredibly small size
  • Human herpes virus is 0.1-0.2um
  • Simple chemical composition (phospholipid envelope, nucleic acid genome, protein capsid, spike projections)
  • No intracellular organelles meaning they are obligate intracellular parasites
  • Genetic info is either DNA or RNA
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2
Q

Give an example of viral replication for a DNA virus? Give the 8 key stages

A
  • Herpes Simplex
    1. Binding to receptor molecules in host cell membrane
    2a/2b. Entry of envelope fusing to host membrane
    3. Release capsid into cytoplasm and Nuclear transport (whilst VHS virion host shutoff degrades host cells mRNA)
    4. Nuclear entry of herpes chromosome through nuclear pore
    5. VP16 causes Gene expression of immediate early mRNA and LAT mRNA
    6. DNA replication by DNA polymerase
    7. Packaging of DNA into capsids and envelopes
    8. Egress of completed virion in epithelial cells
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3
Q

What are the two types of infections associated with herpes simplex and what type of mRNA creates them?

A
  • Lytic infection created by immediate early mRNA
  • Latent infection created by LAT mRNAs (stay dormant in nerve cells and can later cause lytic infection)
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4
Q

What are the principles of Laboratory diagnosis?

A
  • History and examination
  • Provisional diagnosis
  • Diagnosis
  • Take appropriate specimen if needed
  • Detection of viral nucleic acid (detecting nucleic acid amplification)
  • Or serology (detecting nucleic acid amplification or antibody levels)
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5
Q

How would you take a viral swab?

A
  • Use flocked swab
  • Place in molecular sample solution (MSS)
  • After immersion remove swab
  • Label correctly and send to lab
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6
Q

How would you take a blood sample? What can they be used for?

A
  • EDTA (purple top)
  • Serology or molecular
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7
Q

For maculo papular / erythematous lesions what are the common pathogens found , what specimen would you take and what is the lab testing for?

A
  • Enterovirus, HHV6, HHV7, Measles, Rubella
  • Mouth swab
  • DNA/RNA detection
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8
Q

For vesicular lesions what common pathogens are found in the lesion, what specimen would you take and what is the lab testing for?

A
  • HSV1, HSV2, VZV, Enterovirus
  • Mouth swab
  • DNA/RNA detection
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9
Q

For ulcers what common pathogens are present, what specimen would you take and what test would you do?

A
  • HSV, Enterovirus
  • Mouth swab
  • DNA/RNA detection
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10
Q

For maculo papular/ erythematous lesions when using serology what is the common pathogens found, what specimen would you take and what is the lab testing for?

A
  • B19, CMV, EBV
  • EDTA blood
  • DNA/RNA detection or serology
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11
Q

What virus are included in the Human Herpes Virus infections?

A
  • Herpes simplex type 1
  • Herpes simplex type 2
  • Varicella zoster
  • Epstein Barr
  • Cytomegalovirus
  • HHV-6
  • HHV-7
  • HHV-8 (Kaposi’s Sarcoma Associated virus)
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12
Q

What are 3 common features of Human herpes Virus’?

A
  • Primary infection
  • Period of latency
  • Recurrent infection

All have slightly diff clinical features of these stages

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13
Q

What are the clinical features of Herpes simplex types 1 & 2?

A
  • Gigivo stomatitis
  • Herpes labialis
  • Keratoconjuctivitis
  • Herpetic whitlow
  • Bell’s palsy
  • Genital herpes
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14
Q

What is the pathogenesis of HSV-1?

A
  • HSV-1 enters mucosal surface or through damaged epithelium (is a mucocutaneous disease)
  • Replicates in the epithelial cells which give the classic cold sore characteristic
  • HSV is taken up by sensory neurones undergoing retrograde transport back to sensory ganglia
  • Latent infection is established in the sensory ganglia
  • Latent virus lies dormant until reactivation of the virus occurs in the neuron (most likely the trigeminal ganglion)
  • Virions then transported back down the neuron in anterograde fashion to the epithelial cells (recurrent infection) where viral shedding, epithelial shedding and cold sores appear
  • Can feel tingling or pain before recurrent lesions occur (Aciclovir can be used to reduce the mitigation)
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15
Q

What is the epidemiology of Herpes simplex virus?

A
  • Very common infection >90%
  • It’s reservoir is Saliva
  • Approx 30% asymptomatic shedding (infection control vital)
  • Route of transmission is direct by close person to person contact
  • Occurrence is common in childhood
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16
Q

When might a lab diagnosis be needed for cases of HSV ? What swab would you use?

A
  • Atypical cases usually HSV reactivation in immunocomprimsed host
  • Vesicle/ulcer fluid swab and molecular sample media for PCR
17
Q

What is the treatment according to SCDEP for Herpes simplex virus in non-immunocompromised pts?

A
  • Local measures of avoid dehydration and alter diet to include soft foods and adequate fluids
  • Use analgesics and antimicrobial mouthwash
  • Chlorhexidine mouthwash 0.2% 300ml rinse mouth 1 min with 10ml twice daily
  • Aciclovir cream 5% , send 2g , label apply to lesion every 4 hrs (five times daily) for 5 days
18
Q

What is the txt of herpes labialis in immunocompromised pts and sever infections in non-immunocompromised pts according to SDCEP?

A
  • Aciclovir tablets 200mg, Send 25 tablets, label 1 tablet five times daily
19
Q

What is the varicella infection?

A
  • Chicken pox
  • Primary infection varicella
  • Vesicles all along the epithelium
20
Q

What is the incubation period for varicella?

A
  • 10-21 days
21
Q

What are some complications of varicella?

A
  • Secondary bacterial infections
  • Pneumonia
  • Congenital, perinatal/neonatal
22
Q

What are the signs and symptoms of Zoster(Shingles) virus?

A
  • Vesicles appear in dermatome, representing cranial or spinal ganglia where virus has been dormant
  • Affected area intensely painful with associated paraesthesia
  • Not crossing mindline
23
Q

What are some complications of Zoster virus?

A
  • Post herpetic neuralgia
  • Secondary bacterial infections
  • Ophthalmic zoster
  • Ramsay Hunt syndrome (signs and symptoms link to paralysis of facial nerve)
24
Q

What is the Varicella-Zoster pathogenesis?

A
  • Primary infection with varicella zoster virus appears on epithelium as chickenpox lesions
  • Virus travels down by retrograde transport in a period of latency in the trigeminal ganglion where it remains dormant
  • Reactivation of latent virus from trigeminal ganglion transport to epithelium again as zoster lesions
25
Q

What is the epidemiology of Varicella?

A
  • Very common >90%
  • Source is contact with varicella and zoster
  • Highly infectious esp respiratory secretions (48hrs pre symptoms) , or vesicle fluid infections
26
Q

What is the epidemiology of the zoster part of VZV?

A
  • Latent virus remains in sensory ganglion (trigeminal)
  • Low rate of transmission from vesicle fluid
27
Q

What is the route of transmission of VZV?

A
  • Direct contact, droplet or airborne spread
28
Q

What is the occurence of VZV?

A
  • Varicella - highest in children
  • Zoster - highest in elderly and immunocompromised
29
Q

When might a lab diagnosis be needed for VZV? What swab would you use?

A
  • Can be useful for atypical cases
  • Vesicle/ulcer fluid swam and molecular sample media for PCR
30
Q

Who is the varicella vaccination given to?

A
  • Only offered on NHS yo people in close contact with someone’s who’s vulnerable to chicken pox and its complications
31
Q

What can the pain from shingles mimic?

A
  • Pain from toothache
32
Q

What is the prevention of Zoster and who is it offered to?

A
  • Zostavax vaccine
  • Live attenuated virus
  • Offered to all people aged 70+
33
Q
A

BDS4 Oral Medicine (18 decks)

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