Joint Venture
This biaxial condyloid joint links the radius to the scaphoid and lunate.
What is the radiocarpal (wrist) joint?
An IgM antibody that attacks the Fc portion of IgG.
What is rheumatoid factor?
The calcium-dependent enzymes that turn arginine into citrulline.
What are peptidylarginine deiminases (PAD2/PAD4)?
The reduced folate that rescues patients from methotrexate toxicity.
What is leucovorin (folinic acid)?
The two river valleys where Histoplasma lives in bird- and bat-rich soil.
What are the Ohio and Mississippi River valleys?
Osteoarthritis and psoriatic arthritis hit these finger joints; RA usually spares them.
What are the DIP joints?
The antibody with ~95% specificity for RA, targeting a modified amino acid.
What is anti-CCP (ACPA)?
The HLA-DRB1 motif at residues 70–74 that presents citrullinated peptides.
What is the shared epitope?
Her TNF drug's structure, in five words.
What is a fully human IgG1 monoclonal antibody?
Tender red shin nodules she developed, a septal panniculitis.
What is erythema nodosum?
Below the talus, this joint handles inversion and eversion and is often hit in RA feet.
What is the subtalar joint?
Synovial fluid with 80,000 WBCs, >90% neutrophils and a positive Gram stain.
What is septic arthritis?
The invasive, tumor-like sheet of inflamed synovium that eats cartilage.
What is pannus?
The only TNF-α inhibitor with no Fc region, favored in pregnancy.
What is certolizumab pegol?
The fungal enzyme itraconazole inhibits to block ergosterol synthesis.
What is lanosterol 14α-demethylase (CYP51)?
Negatively birefringent, needle-shaped crystals in a hot big toe.
What is gout?
The earliest radiographic sign of RA, seen on her X-ray.
What is periarticular osteopenia?
The ligand that switches on osteoclasts; denosumab blocks it.
What is RANKL?
Low-dose methotrexate works largely by raising this anti-inflammatory nucleoside.
What is adenosine?
Itraconazole's boxed warning names this cardiac condition.
What is heart failure?
This RA deformity pairs PIP hyperextension with DIP flexion.
What is swan-neck deformity?
Her positive anti-SS-A/SS-B plus dry eyes and mouth point to this diagnosis the case never names.
What is secondary Sjögren syndrome?
Neutrophils cast these chromatin webs, citrullinated by PAD4, adding more autoantigen.
What are neutrophil extracellular traps (NETs)?
This antibiotic combination, given with methotrexate, risks pancytopenia by adding a second antifolate hit.
What is trimethoprim-sulfamethoxazole (TMP-SMX)?
Histoplasma urine antigen cross-reacts with this fungus, known for broad-based budding.
What is Blastomyces?