0724 - Lupus Pathology and Treatment Flashcards
Define Lupus
A heterogeneous autoimmune disease, of complex pathogenesis, and protean clinical manifestations characterised also by immunological criteria including production of autoantibodies, usually against cell nuclei.
What is the pathophysiology of lupus?
Interaction of innate and adaptive immunity allowing production of autoantibodies, acute tissue inflammation and damage.
What cells are involved in pathophys of lupus?
Innate - Dendritic, macrophages, B-cells
Adaptive - subsets of T and B lymphocytes.
What are the 3 primary cutaneous manifestations of lupus?
Malar butterfly rash (maculo-papular) and/or Photosensitivity (rash post-UVB exposure) (together these are the acute rashes)
Subacute Cutaneous Lupus (begin as small, psoriatic or annular papules) on neck/shoulders/upper torso/scalp. Only has SSA as the autoantibody, not ANA.
Discoid Lupus - Discrete, erythematous plaques with scale, scars.
Also oral ulcers, alopecia.
What are the primary joint manifestations of lupus?
Arthritis/Arthralgia
Osteonecrosis
Osteoporosis
Myalgia and mild muscle weakness.
Describe Arthritis/Arthralgia in lupus (course, joints affected, imaging, associations)
Migratory - gone in 24 hours.
Tends to hit finger PIPs, wrists, knees, pain exceeds physical findings.
Rarely erosive on Xray and tends to be reducible.
Associated with SSA and SSB.
Describe Osteonecrosis in lupus
Blood supply interruption to head of femur or humerus. Generally bilateral, initially asymptomatic.
What are the criteria of lupus?
Acute cutaneous lupus rashes (commonly malar)
Chronic cutaneous lupus
Oral Ulcers
Nonscarring Alopecia
Synovitis of 2 or more joints. (continue)
Why is SLE difficult to diagnose and classify?
The pathogenesis is uncertain, and there is a wide range of clinical symptoms and signs. There are very few tests or signs that are specific to Lupus, and those that are are not particularly sensitive.
What are the potential immunological findings in SLE?
Order ENA (extractable Nuclear Antibodies, ANA, dsDNA, Complement, Direct Coombs)
ANA (sensitive, not specific)
Anti-dsDNA (very specific if 2xULN)
Anti-RNA - particularly anti-Sm (Smith - specific)/RNP - also SSA/SSB
Antiphospholipid antibodies
Low complement (C3, C4, CH50
Direct Coombs
What tests can be used to distinguish Lupus from RA?
CCP and RF - High CCP shouldn’t be Lupus - most valuable.
Plain films - Lupus won’t show erosions
Kidney Biopsy - Lupus nephritis
What are the principles of management of SLE?
Monitor disease activity and treat flares symptomatically
Monitor for adverse drug effects and treat - infection, osteoporosis
Monitor and great for vascular risk factors (need to complete)
Hydroxychloriquine best drug for it.
