Mrs. Smith, a 40-year-old teacher, has just moved to a new community has decided it is time to select a family physician. For some time now she has avoided consulting a physician, but the pain in her wrists, elbows, ankles, and knee joints is relentless despite the increase in her daily dose of aspirin. Additionally the joints are red and swollen.
When taking her family history, the physician learned that her mother and older sister had both been diagnosed with rheumatoid arthritis. When Mrs. Smith asked him why aspirin was not particularly effective, he explained that aspirin inhibited two enzymes, cyclooxygenase-1 and cyclooxygenase-2 (COX-1 and COX-2) when, in fact, inhibition of COX-2 was what was required to relieve inflammation and joint pain. He further explained that the inhibition of COX-1decreased the production of molecules that induced mucus production in the stomach and facilitated kidney water excretion. Because individuals who take aspirin to relieve the effect of inflammation are also inhibiting COX-1, they are at risk for bleeding ulcers and water retention.
The physician then ordered serum tests that could confirm the diagnosis of rheumatoid arthritis. Also, he gave her a prescription for a specific COX-2 inhibitor, a drug recently approved by the FDA. In addition, he recommended that she read a particular review article that described the role of TNF in inflammation and the clinical trials designed to use anti-TNF antibodies as therapy for certain groups of patients who had rheumatoid arthritis.
Laboratory Data:
Assay Patient Results Reference Range
C-reactive protein 8 mg/dL < 0.5 mg/dL
CCP IgG antibodies 100 Units < 20 Units
IgM Rheumatoid Factor Positive Titer = 64 Negative
ANA Negative Negative
Anti - dsDNA Negative Negative
Serum complement C3 1.1 mg/mL 0.75 รขยย 1.65 mg/mL
Questions:
1.What is the role of TNF in rheumatoid arthritis? What is the anticipated outcome when anti-TNF antibodies are injected in patients with RA?
2.What genetic associations exist with RA and the occurrence of RA relative to gender?
3.What is Rheumatoid Factor?
4.Why is Cyclic Citrullinated Peptide antibodies ordered for the initial diagnosis of RA?
5.Why were ANA and Anti-dsDNA ordered on this patient?
6.Which test is used to monitor inflammation levels after diagnosis?