JOINT PAINS
History
A 38-year-old woman presents to her general practitioner (GP) complaining of pains in her joints. She has noticed these pains worsening over several months. Her joints are most stiff on waking in the mornings. The joints that are most painful are the small joints of the hands and feet. The pain is relieved by diclofenac tablets. She feels tired and has lost 4 kg
in weight over 3 months. She has had no previous serious illnesses. She is married with two children and works as a legal secretary. She is a non-smoker and drinks alcohol only occasionally. Her only medication is diclofenac.
Examination
On examination she looks pale and is clinically anaemic. Her proximal interphalangeal joints and metacarpophalangeal joints are swollen and painful with effusions present. Her metatarsophalangeal joints are also tender. Physical examination is otherwise normal.
Questions
• What is the diagnosis and what are the major differential diagnoses?
• How would you investigate and manage this patient?
ANSWER
This patient has symptoms and signs typical of early rheumatoid arthritis. Rheumatoid arthritis is a chronic, systemic inflammatory disorder principally affecting joints in a peripheral 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 progresses 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, pulmonary nodules, obliterative bronchiolitis, pericarditis and splenomegaly (Felty’s syndrome). 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.
Differential diagnosis of an acute symmetrical polyarthritis!
• 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.
This patient should be referred to a rheumatologist for further investigation and management. 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 metatarsophalangeal joint. Blood tests should be taken for rheumatoid factor (present in rheumatoid arthritis) and anti-DNA antibodies (present in systemic lupus erythematosus). 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 rheumatoid arthritis.
KEY POINTS
Rheumatoid arthritis tends to spare the distal interphalangeal joints.
• Systemic symptoms of rheumatoid arthritis may precede the joint symptoms.
• Anaemia and ESR correlate with disease activity.
• NSAIDs may adversely affect renal function.
Orthopedic Surgery
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General Medicine
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