Arthritis Flashcards
How common is Juvenile Idiopathic Arthritis? Increased or decreased in recent years?
13.9 cases per 100,000 per year, but incidence has decreased in recent years.
How many cases of JIA in the US?
70k to 100k
What is the affected female to male ratio?
2-3:1 but in children under 8 years old the ratio is 8:1 (female:male). Occasional seasonal variance.
Is there any family involvement in JIA?
no consistent Mendelian or monogenic patterns, but slight family involvement. families w/ multiple affected members isn’t common (if multiple family members have it in family, most have the same type).
What type of foci are associated in the development of JIA?
Multiple HLA foci are associated, but some HLA class II alleles can be protective possibly
What are environmental factors that increase the risk for JIA?
Infections (rubella virus and immunization, EBV, flu, parvovirus B19, chlamydia, mycoplasma), maternal tobacco use, and HLA-B27+ (can be triggered by bacterial infections in kids and adults
What are environmental factors that can decrease the risk for JIA?
Breastfeeding, vitamin D/sun exposure
What is the major clinical manifestation of JIA? What does this result in?
persistent joint swelling due to synovial fluid volume and synovial thickening (membrane).
Results in deformities bc periarticular ligaments and tendons stretch and activity of osteoclasts. Osteoclasts are stimulated bc of increased levels of cytokines (produced by inflammatory cells/tissue)
How is synovial fluid affected in JIA?
It’s increased in volume, decreased in viscosity. The synovial fluid is filled with inflammatory cells (PMNs, plasma cells, DCs, T cells)
What is pannus in synovial tissue?
Abnormal layer of synovial tissue. This layer causes joint damage bc they’re filled with inflammatory cells. It’s almost a tumor-like expansion of pannus, which adheres to intraarticular cartilage. (pannus/cartilage junction is where cartilage is degraded/destroyed bc increased blood supply and increased inflammatory cell infiltration).
What is chronic synovitis?
villous hypertrophy and hyperplasia with edema and hyperemia (excess of blood in supplying vessels) of subsynovial tissues
What does pannus formation in synovial tissue lead to in JIA?
destruction of cartilage and bone as disease advances
What do parents often relate JIA symptoms to?
sports injuries, though usually not
What are some molecular targets of biologis in the pathogenesis of JIA?
B cells (CD20), TNF alpha, IL-1, IL-1 receptor, IL-6 receptor, APC (CD80/86)
What does JIA lead to in the joint?
excess fluid in joint cavity, swollen/inflamed synovial membrane, thinning cartilage, bone erosion
What symptoms lead to clinical manifestation? Is it subtle or very acute?
morning stiffness, joint pain, fatigue, fever, swollen/non-erythematous/warm to touch joints.
Can either be subtle or very acute.
What are the 3 major types of JIA?
Systemic onset JIA (Still’s Disease), Pauciarticular JIA (4 or fewer joints at 6 months), Polyarticular JIA (5 or more joints affected at 6 months.
When is systemic onset JIA referred to as adult-onset Still’s?
if onset is after 16 yo
Does Systemic Onset JIA affect males or females more? How do patients appear?
Trick question, only form that affects males and females equally.
Patients appear ill (fever, rash, elevated WBC, anemic) and is often mistaken for infectious or neoplastic disease
What’s the most common early sign of systemic onset JIA? Which joints do it affect? What’s the joint it affects that is not seen in other types?
arthralgias (not joint pain/arthritis).
can affect any joint (most often wrist, knee, ankles).
Will invlove hip (not seen in other types).
What can be present in chronic version of Systemic Onset JIA after years of disease?
Micrognathia (undersized jaw) and cervical spine fusion.
What are extra-articular manifestations of Systemic Onset JIA?
Intermittent fever (>39 degrees C), rash (most often axilla and waist). The rash can disappear when temp returns to normal, may reappear w/ stroking of skin (KOEBNER PHENOMENON) or other trauma.
What are some other clinical findings/signs of Systemic Onset JIA?
organomegally (liver/spleen), lymphadenopathy, pleural & pericardial effusions (small), vasculitis, ill appearance (anemia/systemic effect), headaches and other neurological complaints.
What are lab findings of Systemic onset JIA?
WNO specific lab/diagnosis of exclusion.
See elevated WBC (up to 60k, granulocytes predominate), profound anemia, elevated sedimentation rate, elevated C-reactive protein.