47: Verruca Plantaris - Mahoney Flashcards Preview

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Flashcards in 47: Verruca Plantaris - Mahoney Deck (22)
1

describe virus of verruca plantaris

HPV double stranded DNA icoshohedral capsule (20 sides)

2

why are some people more susceptible to verruca than others?

Persistence of disease may be attributable to a lack of Langerhans’ cells at site of lesion, leading to decreased T-cell response

More common in children, rare over the age of 50, common in immunosuppressed pts

3

pathognomonic characteristics

***

  • acanthosis
    • thickening of stratum spinosum
  • hyperkeratosis
    • thickening of stratum corneum
  • interpapillary projections (papillomatosis)
    • upward proliferation of epidermis and subepidermal papillae causing surface of epidermis to show irregular undulation

  • ***purely epidermal

4

where does DNA and prtn production occur?

final virus assembly?

spinosus layer

granular layer

5

what causes the "black dots" or "petechia" seen clinically w/i white, fibrotic base of wart?

Papillomatosis result in the characteristic “black dots” or “petechia” that are seen clinically within the white, fibrotic base of the wart

6

HPV forms that cause plantar warts

-HPV-1 (common wart)-occurs most frequently

  -HPV-2 (mosaic wart)

  -HPV-4 (common wart)

  -HPV-10

  (HPV-63 has also been implicated)

7

After removing overlying hyperkeratosis from a wart, will see ...

a white, fibrotic-like area with presence of “dots” that interrupts the normal skin lines and bleeds easily upon debridement

8

IPK vs. porokeratosis location

•IPK’s most often confined to weight-bearing areas and covered by thick plug of hyperkeratosis

•Porokeratosis found anywhere on plantar surface, similar to verruca

9

describe porokeratosis

  • Porokeratosis is actually a small clonal projection of keratinizing squamous cells
  • Have a coronoid lamellae-columns of parakeratotic keratin that overlie a depression in the surface epithelium
  • this leads to a prominent rim around the lesion

10

what cancer can warts become?

  • Some evidence to suggest that verrucae may undergo transformation to squamous cell carcinoma
  • very uncommon
  • consider this possibility if you have a resistant wart that looks more “fleshy” than normal and perform biopsy

11

chemical ablation tx

  • topical salicylic acid is most common
  • keratolytic agent
  • applied once or twice daily by pt under occluison and turns skin white
  • cantharidin (blister beetle) and pdophyllin (american mandrake) applied in office under 24-48 hr occlusion causing severe blister

12

cryosurgery

  • liquid nitrogen in spray canister best, can use q-tips dipped
  • cell death occurs below -20 C
  • triple freeze technique
    • administer for 30 sec or until pain, wait until regains color and then refreeze 2 times
  • will form hemorrhagic blister, follow in 2 wks

13

topical treatments

  • Topical corticosteroid under occlusion

    • inhibits cell division and synthesis of DNA in epidermis-apply bid

  • Tretinoin topical vit A

    • increases differentiation and proliferation of epidermis-apply bid under occlusion

  • 5FU

    • inhibits DNA synthesis, apply BID under occlusion

 

 

 

14

oral medications

  • systemic etretinate at dose 1 mg/kg dialy for no more than 3 mo
    • systemic retinoid for psoriasis
  • tagamet/cimetidine 25-40 mg/kd/day
    • interferes with suppressor t-cell function so inflammatory response against virus prolonged

15

intralesional injection therapy

  • 0.1% bleomycin (cancer drug)
    • inhibits DNA synthesis
    • no more than 0.25 cc injected into wart, numb with local first
  • candida antigen
    • Introduce antigen into base of wart with needle in same concentration as with allergy testing, then puncture wart aggressively

    • Induces immune response

16

immunotherapy

  • theory: induce a delayed cutaneous hypersensitivity reaction against the wart by sensitizing the patient with squaric acid dibutylester (SADBE)
    • Apply 3% topical SADBE in acetone to lesions (or to normal skin close to wart) under occlusion for 48-72 hours; After 2 weeks, serial dilutions of SADBE (.03%-3%) are applied to the lesions twice a week; If no response after 10 weeks, patient is a nonresponder
  • imiquimod/aldara cream
    • recruits cytokines and interferon-alpha to wart to induce keratinocytes to produce enzymes to block viral replication

17

name MOA for following tx

5-FU

Imiquimod 

Salicylic acid

SADBE

Tagamet 

a. keratolytic

b. inhibits suppressor t-cell response

c. recrutis cytokines to area

d. inhibits DNA synthesis

e. initiates delayed hupersentivity reaction

d

c

a

e

b

18

surgical ablation techniques

  • Needling
    • works by destruction of tissue and induction of inflammatory response
  • Curettage
    • blunt dissection with tissue nipper, curette down to superficial fascia, cauterize base
  • Hyfercation
    • spark-gap, tissue dehydration precedes charring, and cell death ensuses with thrombosis of blood vessels
  • Sharp surgical excision
    • high rate recurrence and scar formation

19

laser ablation techniques

  • CO2 or pulsed dye lasers
    • Light passed through a CO2 gas chamber is absorbed primarily by water, while light passed through dye emits light absorbed primarily by red pigment (i.e. blood hemoglobin)

    • CO2 needs local anesthetic, pulsed dye does not

20

which is true?

1.The CO2 laser is attracted to hemoglobin

2.The pulsed dye laser is attracted to water

3.The pH of a chlorinated pool is verruccacidal

4.The verruca virus is a double-stranded RNA HPV

5.The verruca virus does not spread into the dermis

5

21

recommendation for children

I recommend mixture of 5-FU and 17% sal acid under occlusion with duct tape, followed by imiquimod, then oral Tagamet®, and lastly, pulsed dye laser

If you cause pain in a child, you’ll only have that one chance, so make it work

In adults, I would start out with liquid nitrogen and once daily application of 5-FU plus 17% sal acid under occlusion with duct tape, followed by Aldara®, followed by pulsed dye laser plus Aldara® if unsuccessful

Remember you are dealing with a benign lesion, so “firstly, do no harm”

22

always use ...

combination tx

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