Oral Med - Vesiculobullous Diseases Flashcards
What type of immune mediated disease is pemphigus and pemphigoid?
immunogenic - through antibody mediated immunity
What type of immune mediated disease is erythema multiforme?
hypersensitivity type 3
Describe why immunological skin and oral diseases are linked and share some common antigens and epitopes.
Immunological skin and oral disease linked as embryologically the oral mucosa develops from the same precursor tissue as the skin
Describe briefly what occurs in immunological skin and oral mucosal diseases.
Autoantibody attacks skin components = loss of cell-cell adhesion = a split forms on the skin
- This Fills with inflammatory exudate and forces the layers of the skin apart to form a vesicle or blister
What is the difference between a vesicle and a blister?
size
- Vesicle 1-2mm
- Blister larger
What is the role of desmosomes and hemidesomes? (3)
attach the epithelial cells to each other, to the basement membrane and to the protein desmoglein.
Describe the importance of desmoglein in terms of vesiculobullous disease? (2)
Target for many antibody’s involved in immunobullous diseases.
The way in which the desmogelin and the antibody interact can lead to loss of adhesion between the desmosomes = allows cell layers to split.
How can we test for vesiculobullous diseases?
Direct Immunofluorescent:
Describe how direct Immunofluorescent works?
If you suspect that an antibody is bound to the affected tissues;
Where a secondary (manufactured) antibody with a fluorescein marker attached binds to the primary antibody (from the circulation) bound to the tissues affected by immunobullous disease.
Tissues then examined by fluorescent lighting = shows where the antibodies are bound in the affected tissues.
What type of immunofluorescence is used for diagnosis of VB disease?
direct
what is the role of indirect IF? (2)
good for monitoring disease activity and levels of the antibody
Gives guide to tx need
Describe indirect IF.
Assesses the presence of circulating antibodies not bound to the tissues yet in PLASMA samples
What is an extreme form of erythema multiforme known as?
Stevens-Johnson syndrome
What is erythema multiforme?
A spectrum disorder caused by Immunogenic related skin and mucosa ulceration
Type 3 hypersensitivity reaction related to antigen antibody complexes
Describe what occurs in erythema multiforme.
An antigen presents which is targeted by an antibody
Usually the antigen has been met before by the body therefore a prompt immune response occurs = antibodies produced from memory B cells quickly
The antibody and antigen combines in the circulation = producing a large complex which is unable to pass through the capillaries = complex wedges in tissues and activates compliment within the BV causing a perivascular inflammatory response.
Significant = blistering/ulceration of the tissues
What are the characteristics/features of erythema multiforme? (6)
- acute onset
- M>F
- young males (late teens/early 20’s) – recurrent within a short period and then months ulcer free
- skin = target lesions with a central wheel and a perilesional area of pale mucosa
- ulcers on any part of the oral mucosa (including keratinised tissues)
- Ulceration present on Lips & anterior part of mouth
- Very painful – unable to eat or drink (dehydration)
- severe multisystem involvement
- can affect skin, conjunctivae, nose, pharynx, mouth genital
What is suggested to have a role in oral mucosal erythema multiforme?
herpes simplex
what is a characteristic presentation of erythema multiforme?
Lip crusting and acute illness
How do we manage/treat EM? (4)
- prednisolone - systemic steroids – up to 60 mg/day (a high dose)
- prophylactic systemic acyclovir given to those with repeated oral lesions (suppresses viral replication of the HSV)
- Encourage fluid intake - May require admission for IV fluid if unable to drink due to pain
- Encourage analgesia