Webster's New World Medical Dictionary

rheumatoid arthritis
See 
arthritis, rheumatoid.
rheumatoid arthritis, systemic-onset juvenile
See 
arthritis, systemic-onset juvenile rheumatoid.
rheumatoid factor
An antibody that is measura-
ble in the blood and is used to diagnose rheumatoid
arthritis. Rheumatoid factor is present in about 80
percent of adults, and a much lower proportion of
children, who have rheumatoid arthritis. It is also
present in patients with other connective-tissue dis-
eases, such as systemic lupus erythematosus, and in
some patients with infectious diseases, such as
infectious hepatitis.
rheumatoid nodule
A firm lump in the skin of a
patient with rheumatoid arthritis. Rheumatoid nod-
ules usually occur at pressure points of the body,
most commonly the elbows.
rheumatologist
A physician specialist in the
treatment of rheumatic illnesses, especially forms of
arthritis. There is a subspecialty board for rheuma-
tology certification, the American College of
Rheumatology, which can offer board certification
to approved rheumatologists. See also 
rheumatolo-
gist, pediatric; rheumatology.
rheumatologist, pediatric
A rheumatologist who
specializes in caring for children with rheumatic dis-
eases. Pediatric rheumatologists are pediatricians
who have completed an additional 2 to 3 years of spe-
cialized training in pediatric rheumatology and are
usually board certified in pediatric rheumatology.
They have special interests in unexplained rash, fever,
arthritis, anemia, weakness, weight loss, fatigue, mus-
cle pain, autoimmune disease, and anorexia.
rheumatology
A subspecialty of internal medi-
cine that involves the nonsurgical evaluation and
treatment of rheumatic diseases and conditions.