ANSWER 27
This patient has symptoms and signs typical of early rheumatoid arthritis. Rheumatoid
arthritis is a chronic, systemic inflammatory disorder principally affecting joints in a periph-
eral symmetrical distribution. The peak incidence is between 35 and 55 years in women and
40 and 60 years in men. It is a disease with a long course with exacerbations and remissions.
The acute presentation may occur over the course of a day and be associated with fever
and malaise. More commonly, as in this case, it presents insidiously, and this group has a
worse prognosis. Rheumatoid arthritis characteristically affects proximal interphalangeal,
metacarpophalangeal and wrist joints in the hands, and metatarsophalangeal joints, ankles,
knees and cervical spine.
Early-morning stiffness of the joints is typical of rheumatoid arthritis. As the disease pro-
gresses damage to cartilage, bone and tendons leads to the characteristic deformities of this
condition. Extra-articular features include rheumatoid nodules, vasculitis causing cutaneous
nodules and digital gangrene, scleritis, pleural effusions, diffuse pulmonary fibrosis, pul-
monary nodules, obliterative bronchiolitis, pericarditis and splenomegaly (Felty’s syn-
drome). There is usually a normochromic normocytic anaemia and raised ESR as seen here.
The degree of anaemia and ESR roughly correlate with disease activity. In this case the raised
creatinine is probably due to the use of diclofenac. Non-steroidal anti-inflammatory drugs
(NSAIDs) reduce glomerular filtration rate in all patients. Rarely they can cause an acute
interstitial nephritis. In patients with lond-standing rheumatoid arthritis, renal infiltration
by amyloid may occur.
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- Osteoarthritis: characteristically affects the distal interphalangeal as well as
proximal interphalangeal and first metacarpophalangeal joints. - Rheumatoid arthritis.
- Systemic lupus erythematosus: usually causes a mild, flitting non-erosive arthritis.
- Gout: usually starts as a monoarthritis.
- Seronegative arthritides: ankylosing spondylitis, psoriasis, Reiter’s disease. These
usually cause an asymmetrical arthritis affecting medium and larger joints as well as
the sacroiliac and distal interphalangeal joints. - Acute viral arthritis,e.g rubella: resolves completely.
Differential diagnosis of an acute symmetrical polyarthritisThis patient should be referred to a rheumatologist for further investigation and manage-
ment. The affected joints should be X-rayed. If there has been joint damage, the X-rays will
show subluxation, juxta-articular osteoporosis, loss of joint space and bony erosions. A
common site for erosions to be found in early rheumatoid arthritis is the fifth metatarso-
phalangeal joint (arrowed in Fig. 27.1). Blood tests should be taken for rheumatoid factor
(present in rheumatoid arthritis) and anti-DNA antibodies (present in systemic lupus erythe-
matosus). This patient should be given NSAIDs for analgesia and to reduce joint stiffness to
allow her to continue her secretarial work. Disease-modifying drugs such as methotrexate,
leflunomide, gold or penicillamine should be considered unless the patient settles easily on
NSAIDs. Anti-tissue necrosis factor (TNF) antibody is effective in some severe cases of rheuma-
toid arthritis.