Chapter 30 - Pemphigus Flashcards
What are the 3 major forms of pemphigus?
1) Pemphigus vulgaris, 2) pemphigus foliaceus, 3) paraneoplastic pemphigus. The other forms include 4) drug induced, 5) IgA pemphigus
True/False: All pemphigus foliaceus patients will have mucosal membrane erosions.
False. Pemphigus foliaceus patients only have cutaenous involvement without mucosal lesions.
What are the 2 major subgroups of cadherins?
Classic and desmosomal, which include desmogleins and desmocollins
What are differences between adherens junctions and desmosomes? Hint: what do they anchor, which cadherins do they contain, what are the cytoplasmic components
1) Adherens junctions-anchor actin microfilament bundles, contain classic cadherins, alpha & beta catenin, plakoglobin (quick but weak cellular adhesions); 2) desmosomes-anchor intermediate filaments, contain desmosomal cadherins, plakoglobin, plakophilin, desmoplakin (slow but strong cellular adhesions)
What are the 4 isoforms of desmogleins and where are they found?
Dsg1&3-stratified squamous epithelia; Dsg2-all desmosomes including simple epithelia, myocardium; Dsg4-hair follicles
Which Ag is cleaved by exfoliative toxins such as those produced by S. aureus?
Dsg1. Leads to bullous impetigo, SSSS
What mucosal membrane sites can be involved in PV?
Oral cavity, esophagus, conjunctivae, nasal mucosa, vagina, penis, anus, labia
True/False: PV lesions tend not to heal and those that do, heal with hyperpigmentation and scarring.
False, they heal with NO scarring
Which drugs are most commonly associated with drug induced pemphigus?
Penicillamine, captopril. Most patients go into remission with discontinuation
Which neoplasms are commonly associated with paraneoplastic pemphigus?
Non-Hodgkin lymphoma, chronic lymphocytic leukemia, Castleman’s disease, thymomas, sarcomas, Waldenstrom’s macroglobulinemia
What is the most constant clinical feature of paraneoplastic pemphigus?
Stomatitis, which often extend onto vermilion lip. Severe, presents early on, persists and extremely resistant to treatment
What test is the most reliable and sensitive diagnostic test for pemphigus?
Direct IF (IgG deposition) on skin bx
What is the standard treatment for PV?
Prednisone. Clinical improvement is based on number of new blisters/day, rate of healing. Response in 3-7d
What is the drug of choice for IgA pemphigus?
Dapsone. Response in 1-2d
What is a good treatment option in localized pemphigus foliaceus?
Potent topical steroids
True or false: there are no good treatment guidelines for paraneoplastic pemphigus.
True
True or false: continuous cardiac monitoring is necessary with methylprednisone IV administration.
True; this is due to the potential for electrolyte shifts and resultant cardiac arrest
True or false: ELISA can distinguish between pemphigus vulgaris that involves only Dsg3 and pemphigus vulgaris that involves both Dsg 1 and Dsg3.
True
What type of animal substrate is typically used for indirect IF to detect paraneoplastic pemphigus?
Rat bladder, because it contains transitional epithelium, which will bind antiplakin antibodies
What subclass of IgG is most commonly implicated in pemphigus?
IgG4, which does not fix complement
True or false: DIF is the most reliable and sensitive diagnostic test for all forms of pemphigus.
True
What is the eponymous name for pemphigus erythematosus?
Senear-Usher syndrome
True or false: pruritus is often a common symptom associated with IgA pemphigus.
True
Roughly what percentage of patients with paraneoplastic pemphigus are already aware of their underlying malignancy?
2/3 (66%)
