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FD9 > 198 - Phototherapy > Flashcards

198 - Phototherapy Flashcards

1
Q

Most common short term adverse effect of phototherapy

A

Sunburn-like reactions

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2
Q

UVB phototoxicity usually peaks at _____

PUVA reaction manifests at _____

A

12-24 hours

24-48 or even 72 hours

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3
Q

Long term follow up studies established an increased risk of _____ (3) for PUVA therapy

A

Lentigines
Squamous cell carcinoma
Possibly melanoma

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4
Q

UVB wavelength

A

290-320 nm

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5
Q

UVB radiation types of DNA damage (4)

A
  1. Formation of pyrimidine dimers and 6,4-pyrimidine-pyrimidone photoproducts
  2. Conversion of trans- to cis-urocanic acid
  3. Conversion of tryptophan into 6-formylindololo[3,2-b]carbazole
  4. Generation of reactive oxygen intermediates
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6
Q

Breakdown product of histidine; present in large amounts in stratum corneum

A

Urocanic acid

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7
Q

Effect of cis-urocanic acid

A

Mediator of UVB-induced immunosuppression

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8
Q

Increase in hydroxyvitamin D synthesis inversely correlates with baseline levels of

A

Trans-urocaninc acid

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9
Q

UVA wavelength

A

320-400 nm

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10
Q

Depth of penetration:

  1. UVA
  2. UVB
A
  1. Mid- or lower dermis (140 microns)

2. Epidermis and superficial dermis (14 microns)

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11
Q

Major biologic effects of UVA radiation are from

A

Generation of reactive oxygen intermediates in mitochondrial enzyme complexes during oxidative phosphorylation

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12
Q

UVA1 wavelength

A

340-400 nm

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13
Q

UVA1 has immunoprotective properties via

A

Generation of heme oxygenase-1

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14
Q

Major photochemical effect of psoralen photochemotherapy

A

Damage to DNA

  1. Intercalate with DNA
  2. Production of reactive oxygen intermediates such as singlet oxygen
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15
Q

Have 2 double bonds that can absorb UVA radiation

A

Psoralens

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16
Q

UVB effect on:

  1. Effector T cells
  2. Regulatory T cells
A

Inhibits activation of effector T cells

Leaves the development of regulatory T cells unaltered

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17
Q

Major function of dendritic cells

A

Present antigen to T-lymphocytes

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18
Q

Disruption of activities of dendritic cells through (2)

A

Direct effects of UVB

Indirectly through production of IL-10 and prostaglandin E2

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19
Q

UV exposure significantly lowers levels of immunomodulatory factors such as _____, possibly reflecting a loss of Langerhans cells

A

Prostaglandin D2

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20
Q

Effect of phototherapy in cutaneous lymphoid infiltrates

A

Cell death by apoptosis of T cells

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21
Q

Effect of phototherapy on expression of CD54 and other adhesion molecules

A

Decreased

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22
Q

Facilitates T-cell binding to keratinocytes through its interaction with lymphocyte function-associated antigen-1 that is present on T cells; not normally present on epidermal keratinocytes

A

Intercellular adhesion molecule-1

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23
Q

Effects on immune system provide an explanation for phototherapy’s efficacy in cutaneous diseases in which T-cell hyperactivity predominates such as

A

Psoriasis
Atopic dermatitis
Lichen planus
Cutaneous T-cell lymphoma

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24
Q

Phototherapy for treatment of mast-cell mediated diseases

A

PUVA

UVA-1

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25
Q

PUVA vs UVA1 effects on mast cells

A

PUVA - stabilize mast cell membranes

UVA1 - apoptosis of mast cells

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26
Q

Phototherapy for treatment of sclerotic skin diseases

A

PUVA

UVA-1

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27
Q

UVA downstream effect on collagen

A

Activation of matrix metalloproteinase-1 resulting in degradation of collagen

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28
Q

UVA increases the production of _____ (2) which are stimuli for MMPs

A

IL-1

IL-6

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29
Q

Effect of phototherapy on the epidermis

A

Acanthosis

Thickening of the stratum corneum

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30
Q

Effect of phototherapy on keratinocytes has been exploited for the management of

A

Chronic photosensitivity disorders

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31
Q

Phototherapy stimulatory effects on melanogenesis (decrease/increase) the efficacy of phototherapy

A

Decrease

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32
Q

Markers for stem cell activation in the follicular and interfollicular epithelium

A

Cytokeratins 15 and 19

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33
Q

Phototherapy devices generate light by the conversion of _____ energy into _____ energy

A

Electrical

Electromagnetic

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34
Q

Generate UVR by passing electric current though a thin tungsten filament, which, in turn, generates heat and light

A

Incandescent lamps

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35
Q

Tungsten filament is sealed in a quartz envelope that contains a halogen (bromide or iodine)

A

Quartz halogen lamps

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36
Q

These lamps can emit wavelengths within the UV, visible, and infrared ranges

A

Quartz halogen lamps

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37
Q

Used in situations that require visible light such as phototesting and photodynamic therapy

A

Incandescent lamps/quartz halogen lamps

38
Q

When a high voltage is passed across 2 electrodes in the presence of a gas, the electrons of the gas become excited. When the gas electrons return to their ground state, light is emitted.

A

Arc or gas discharge lamps

39
Q

Example of a metal halide lamp

40
Q

High-pressure arc lamps typically contain _____ or _____, whereas low-pressure arc lamps use _____.

A

Mercury, xenon gas

Fluorescent material

41
Q

Broadening of spectral output of discharge lamps done through (2)

A

Altering the gas pressure

Addition of metal halides

42
Q

Most commonly used sources of therapeutic UVR

A

Fluorescent lamps

43
Q

Chemicals called phosphors/fluorophores absorb and then reemit light. The light that is reemitted is of lower energy (and thus longer wavelength)

A

Fluorescent lamps

44
Q

Examples of fluorescent lamps

A

311 nm NB-UVB

Broadband UVB and UVA

45
Q

UVB combined with the topical application of coal tar as treatment for psoriasis

A

Goeckerman therapy

46
Q

Approximately two-thirds of the output is in the UVB range and the rest is primarily in the UVA

47
Q

Wavelengths that most efficiently clear psoriasis

A

Approximately around 313 nm

48
Q

Wavelengths most efficient at causing erythema and nonmelanoma skin cancer

A

Less than 300 nm

49
Q

NB-UVB light sources emit only wavelengths between

A

308 and 313 nm

50
Q

Initial starting dose of BB-UVB and NB-UVB is determined through (2)

A

Minimal erythema dose

Empirically based on Fitzpatrick skin type

51
Q

MED is determined by exposing six 1-cm2 areas of skin on the _____ or _____

A

Inner aspect of the forearm

Lower back

52
Q

MED reading after _____ hours for NB-UVB

53
Q

Phototherapy is initiated at _____% of the smallest UV dose that results in uniform erythema over the entire area

54
Q

Maximum NB-UVB dose

A

2000-5000 mJ/cm2

55
Q

8-methoxypsoralen preparations

A

Micronized form

Dissolved form

56
Q

8-MOP micronized form administration

A

0.6 mg/kg 120 minutes prior

57
Q

8-MOP dissolved form administration

A

0.4 to 0.6 mg/kg 90 minutes prior

58
Q

More commonly employed preparation of 8-MOP

59
Q

Micronized vs dissolved form of 8-MOP

A

Dissolved preparation:
Absorbed faster
Yields higher and more reproducible serum levels

60
Q

MPD (minimum phototoxic dose) reading after _____ hours for oral UVA

61
Q

Benefits of bath PUVA vs oral

A

Circumvents GI side effects and possible phototoxic hazards to the eyes

62
Q

Initial exposure dose for NB-UVB and oral PUVA

A

50-70% of MED/MPD

63
Q

Initial exposure dose for bath PUVA

A

30% of MPD

64
Q

Tolerance is rapidly lost when exposures cease, requiring downward adjustments of dose after as little as _____ week to avoid burns

65
Q

More than _____ BB-UVB
treatments is associated with a modest, but significant,
increase in squamous cell carcinoma and
basal cell carcinoma

66
Q

Carcinogenic risk
of a single PUVA treatment is approximately _____ times
greater than a single UVB treatment

67
Q

8-MOP acute side effects

A

Nausea and vomiting

68
Q

8-MOP acute side effects more common with which preparation?

69
Q

Contraindicated in individuals who have been treated with PUVA

A

Cyclosporine

70
Q

_____ used concurrently with PUVA reduce the risk of SCC

A

Oral retinoids

71
Q

Relative contraindication for further PUVA therapy

A

Personal or family history of melanoma

History of more than 200 PUVA treatments

72
Q

Recommended first-line therapeutic agents for moderate to severe psoriasis in HIV-positive patients

A

Phototherapy and antiretrovirals

73
Q

NB-UVB dose associated with decrease in serum folic acid levels

A

> 118.16 J/cm2 in 36 treatments

74
Q

BB-UVB dose associated with decrease in serum folic acid levels

A

110-220 mJ/cm2 in 7-22 treatments

75
Q

Special considerations regarding phototherapy in elderly

A

Erythema lasts longer and peaks later

Photoadaptation may be decreased

76
Q

First line therapy (phototherapy) for chronic plaque psoriasis

77
Q

Application of calcipotriol prior to phototherapy leads to _____ (2)

A

Unwanted degradation of vitamin D3

Increases MED

78
Q

Topical medication that should not be used during phototherapy because it blocks UVB penetration

A

Salicylic acid

79
Q

Polymorphism in genes encoding _____ are associated with PUVA sensitivity

A

Glutathione S-transferases

80
Q

Long-term methotrexate, defined as 36 or more months of use, in combination with PUVA may increase the risk of

81
Q

Should not be applied within 2 hours of phototherapy

A

Calcipotriol

82
Q

UVA1 is a therapeutic alternative for treatment of acute exacerbations of

A

Atopic dermatitis

83
Q

Earliest sign of response to phototherapy in vitiligo

A

Perifollicular repigmentation

84
Q

Cosmetically acceptable treatment success in vitiligo is defined as

A

Greater than or equal to 75% repigmentation

85
Q

First-line phototherapy in localized vitiligo

A

308-nm excimer laser

86
Q

Type of phototherapy that does not cause repigmentation

87
Q

Recurrence after successful UVA1 treatment of morphea was dependent on

A

Duration of morphea prior to treatment

88
Q

Phototherapy for photodermatoses typically initiated

A

1 month before the anticipated intense sun exposure

89
Q

Type of phototherapy not particularly effective in preventing solar or other forms of urticaria

90
Q

_____ PUVA is preferable for patients with hyperkeratotic eczema and _____ PUVA is more beneficial for dyshidrotic eczema

FD9 (108 decks)

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