Mucocutaneous - Vesiculo-bullous disease Flashcards

1
Q

Macule (macular lesion) features?

A

Circumscribed flat lesion
Not elevated
Not palpable

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2
Q

Papule (papular lesion) features?

A

Circumscribed raised lesion
Raised
Palpable

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3
Q

Blister

A

Fluid filled sac within or below epithelium

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4
Q

Vesicle

A

Small blister less than 5mm

e.g. herpes simplex virus

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5
Q

Bulla

A

Large blister more than 5mm diameter

e.g. pemphigus/pemphigoid

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6
Q

Erosion

A

Marked thinning/partial loss of epithelium
But with a thin epithelial covering of the CT
Usually looks red and is v sensitive

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7
Q

Ulcer

A

Localised loss of entire thickness of epithelium
Exposes underlying CT
Usually painful

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8
Q

Examples of mucocutaneous disease?

A
Autoimmune bullous disease
- Pemphigus
- Pemphigoid
- Dermatitis herpetiformis 
= Type II hypersensitivity

Epidermolysis bullosa congenita = congenital anomaly
Erythema multiforme = type III/IV
Oral lichen planus and lichenoid reactions = type IV

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9
Q

Autoimmune bullous diseases features?

A

Organ specific
Antibody mediated Type II hypersensitivity
Autoimmune disease

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10
Q

Pemphigus epidemiology?

A

Incidence 0.5-3.2 per 100,000
40-60 yrs old
1:1 M:F
Organ specific autoimmune disease targeting skin and oral mucosa

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11
Q

Oral features of pemphigus?

A

Mouth involved in most cases, only site involved in over half of cases
Palate, buccal mucosa and gingivae - most commonly affected
Bullae - short lived in mouth and on skin
Large shallow non healing ulcers are typical

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12
Q

Pathogenesis of pemphigus?

A
Circulating autoantibodies against binding proteins that keep epithelial cells together (desmosomes).
Binding protein- part of the desmosomal complex,
usually desmoglein3 (sometimes desmoglein 1 as well).
Autoantibody binds to desmoglein3- acantholysis and formation of an intra-epithelial bulla.
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13
Q

Pemphigus histology?

A

Parakeratinised SS epi
CT under it
Bullae either side has epithelium = intraepithelial bullae
Rounded cells in vesicle fluid = sank cells

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14
Q

Pemphigus investigations?

A

Biopsy of para-lesional and/or normal tissue
Send tissue to lab fresh
Routine histology - separate biopsy or part of fresh specimen
Direct immunofluorescence staining - used to detect whether autoantibodies are present in the patient’s tissue

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15
Q

Pemphigus immunofluorescence

A

Positive direct immunofluorescent staining in epithelial cells (fish net pattern)
Autoantibodies (IgG) target desmoglein 3 in the desmosomes that join keratinocytes

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16
Q

Direct immunofluorescence - how does it work?

A

If pt has pemphigus the autoantibodies are present in the sample
Add in fluorescent labelled anti-human IgG to attach to the autoantibody

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17
Q

When are blood samples needed to investigate pemphigus?

A

Circulating desmoglein levels
For indirect immunofluorescence
Used to detect circulating autoantibodies
Not used routinely any more

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18
Q

Indirect immunofluorescence?

A

Sample of pts blood (not tissue) contains autoantibodies added to normal tissue sample and fluorescent labelld anti-human IgG added - will bind

19
Q

Subtypes of pemphigus?

A

Pemphigus vulgaris
- Most common (antibodies mainly DSG3)

Pemphigus foliaceous
- Lesions more superficial (antibodies mainly DSG1)

Paraneoplastic pemphigus

  • Associated with neoplasm
  • Usually lymphoma or chronic lymphocytic leukaemia
  • Extremely serious with a high morbidity and mortality
20
Q

Management of pemphigus?

A

Exclude cancer
Immunosuppression
Prednisolone alone or in combo with azathioprine
Occasionally other immunosuppressants or plasmapheresis

21
Q

How to differentiate intra-epithelial bullae (pemphigus) and sub-epithelial bullae (pemphigoid)?

A
Intra-epithelial bullae - pemphigus:
Partial thickness
Very fragile
On rupturing, basal epithelial cells remain therefore:
- Infec can get in
- Loss of tissue fluids
- = Life threatening 

Sub-epithelial bullae (pemphigoid)

  • Full thickness
  • Less fragile
  • On rupturing, exposed CT
  • Healing by secondary intention: epithelial migration from edges, wound contraction e.g. scarring
22
Q

Pathogenesis of pemphigoid?

A

Autoantibodies against components of the hemidesmosomes: structures gluing epithelial cells to the basement membrane
The targeted part of hemidesmosome varies between different types of pemphigoid

23
Q

Types of sub-epithelial autoimmune bullous diseases?

A

Bullous pemphigoid
Mucous membrane pemphigoid
Dermatitis herpetiformis

24
Q

Histology of bullous pemphigoid/mucous membrane pemphigoid?

A

Epithelium separates from CT at the level of the basement membrane

  • Top = epithelium and under = CT
25
Q

Mucous membrane pemphigoid?

A

Chronic disease of elderly
Desquamative gingivitis >90% of cases
Buccal mucosa and palate often involved
Eyes may be severely damaged by scarring - cicatricial pemphigoid
Skin lesions are rare in MMP
Autoantibodies directed against BP230, laminin and Alpha6Beta4 in hemidesmosomes

Gingival involvement in more than 90% of cases
82.5% other oral mucosa
48.3% conjunctiva = inversion of lower eyelid (droopy)
Skin and nasal

26
Q

Mucous membrane pemphigoid signs?

A

Well marginated ulcers
Healing in 3-4 weeks, risk of scarring if eyes, larynx, oesophagus involved
Erythematous, friable, tender gingivae
Nikolsky sign positive (shearing away of the epidermis)
Conjunctival lesions common: lid inversion (droopy), symblepharon, ankyloblepharon

27
Q

Eye lesions with MMP?

A

Trichiasis, fibrosis and scarring
Inversion of lower eyelid (droopy)
Entropion plus adhesions = symblepharon
Ankyloblepharon = both eyelids start to stick together

28
Q

Treatment for MMP?

A
Steroids
- Topical/systemic if severe
Plaque reduction
- Daily scruptulous home care
- Chlorhexidine
Tetracycline/nicatinamide (B3)
Other immunosuppressive agents
- Azathioprine, cyclophosphamide, dapsone, mycophenolate
29
Q

What to do if you suspect MMP?

A

Phone

Needs opthalmology opinion

30
Q

BP/MMP investigations?

A

Biopsy of para-lesional and/or normal tissue
Send tissue to lab fresh
Routine histology
Direct immunofluorescence staining: to detect autoantibodies
Linear IgG or IgM immunofluoresence at the basement membrane
Indirect immunofluoresence usually negative

31
Q

BP/MMP immunofluorescence result?

A

Linear IgG or IgM immunofluorescence at the basement membrane
Standard indirect immunofluorescence studies usually negative

32
Q

Management of MMP/BP?

A

Systemic or topical steroids - mainstay of tx
Sulphonamides or dapsone - may be an effective alternative to systemic steroids
Mycophenolate mofetil
Ocular examination

33
Q

Dermatitis herpetiformis features?

A

May affect a younger age group including children
Smaller bullae and vesicles = herpetiform appearance of lesions - ask if they have any stomach, eye or skin problems
Associated with coeliac disease

34
Q

Management of dermatitis herpetiformis?

A

GF diet

May respond well to sulphonamides or dapsone

35
Q

Histology of dermatitis herpetiformis?

A

Small regions of epithelial separation at the level of the basement membrane
Neutrophil/eosinophil abscesses
Mixed inflammation in CT

36
Q

Immunofluorescence of dermatitis herpetiformis?

A

Speckled/granular IgA immunofluorescence - basement membrane and adjacent CT
= Speckled texture

37
Q

Epidermolysis bullosa congenita features?

A

Not autoimmune (inherited)
Genetic defects in key proteins involved with epithelial integrity or anchoring to the CT
Variable clinical picture depending upon which protein is defective
Mainly affects children - often present at birth
Some forms are severe, mutilating or fatal

38
Q

Epidermolysis bullosa congenita types?

A

EB simplex
EB junctional = most severe
EB dystrophica

39
Q

Epidermolysis bullosa congenita signs?

A
Large erosive lesions
Large bullae
Raw wounds
Quite common on hands and feet
Scarring
40
Q

Erythema multiforme?

A

Acute onset, short duration 2-3 weeks
Mucocutaneous blistering disorder
Peak age range 20-30 yrs
Complex pathogenesis
Some cases immune complex mediated - type III hypersensitivity, immune complexes deposited in tissues
Some recurrent cases - type IV hypersensitivity to herpes antigens

41
Q

Erythema mutliforme clincial features?

A

Oral

  • Haemorrhagic crusting of lips
  • Extensive irregular mucosal ulceration erythema and blistering

Ocular
- Conjunctivitis

Skin
- Target lesions

Severe cases
- Steven’s johnson syndrome

42
Q

Causes of single episode and recurrent erythema multiforme?

A

Single episode

  • Drugs
  • Mycoplasma pneumonia
  • Radiotherapy
  • Idiopathic

Recurrent
- Recurrent herpes simples (cold sores)

43
Q

Management of erythema multiforme?

A
Remove/avoid trigger
Short, reducing dose course of steroids
Chlorhexidine/benzydamine mouthwash
Gelclair
Analgesics
Soft diet
Admission for parentaral nutrition and more intensive therapy 

Recurrent
- Prevention with systemic aciclovir

44
Q

Bullous pemphigoid features?

A

Skin usually involved with bullae and large shallow ulcers or erosions
Mouth and other mucous membranes frequently involved
Autoantibodies directed against the BP180 and BP230 antigens in hemidesmosomes