Category Archives: Rheumatology and bone disease

OTHER ANTIBODIES

Anticardiolipin antibodies

These are found in the antiphospholipid syndrome, which is described Antineutrophil cytoplasmic antibodies (ANCA) These are detected by immunofluorescence and by enzyme-linked immunosorbent assay (ELISA) in the serum, and are of two types:

1 cANCA (cytoplasmic staining) is directed against serine proteinase C.
2 pANCA (perinuclear staining) is mainly directed against myeloperoxidase. cANCA is seen in Wegener’s granulomatosis with a specificity of about 90%. It is found in 50% of early cases and almost 100% of cases with full-blown systemic disease. It disappears with treatment and rising titres may predict relapse, making it a very useful marker of progress. It is very occasionally found in other types of vasculitis such as microscopic polyarteritis.
pANCA is much less specific and is found in:

• Various types of vasculitis including microscopic polyarteritis, Churg-Strauss syndrome and sometimes polyarteritis nodosa
• Glomerulonephritis
• Rheumatoid arthritis
• Connective tissue disorders such as SLE and Sjogren’s syndrome, not necessarily associated with vasculitis
• Chronic inflammatory bowel disease, in primary sclerosing cholangitis and in autoimmune hepatitis
• Drug treatment, e.g. hydralazine.

SERUM URICACID

A raised serum uric acid is a good confirmatory test for gout, but is not diagnostic. A low level of uric acid excludes gout. In known cases of gout, the uric acid level is helpful in deciding treatment.

JOINT PUNCTURE

SYNOVIAL FLUID EXAMINATION

The characteristics of synovial fluid in normal and diseased joints are shown Polarized light microscopy reveals the presence of negatively birefringent crystals in gout. In pyrophosphate arthropathy, crystals of calcium pyrophosphate, which are ‘eakly positively birefringent, are seen. Crystals of hydroxyapatite are too small to be seen in polarized light microscopy and need to be identified using electron microscopy. Gram stain may identify organisms in septic arthritis but the fluid should also be cultured.

X-RAYS

X-rays show characteristic abnormalities in many rheumatic conditions; these are described in the appropriate sections. Degenerative changes are present in almost everyone by the age of 65 years and often before; their presence on an X-ray does not necessarily therefore mean osteoarthritis. X-rays are of little value in acute conditions such as
septic arthritis.

OCCASIONALL Y USEFUL TESTS

“WHITE BLOOD CELL COUNT is useful in infections and eukaemia presenting with arthritis.

Joint puncture.

Joint puncture.

RAISED SERUM ALKALINE PHOSPHATASE is characteristicof  Paget’s disease (see p. 428) but is also sometimes seen in active rheumatoid arthritis and polymyalgia rheumatica.
A MONOCLONAL PROTEIN BAND on serum electrophoresis is found in myeloma.
RAISED ANTISTREPTOLYSIN-O (ASO) titre indicates recent streptococcal infection. Very high levels are characteristic of rheumatic fever.
HIGH SERUM TRANSFERRIN SATURATION OR FERRITIN LEVEL occurs in haemochromatosis, which may present with arthritis.
Low SERUM COMPLEMENT may be found in the active phase of SLE.
ARTHR0SCOPY is useful for the demonstration of mech anicallesions in the knee joint such as a torn meniscus and if necessary a synovial biopsy can be obtained during the procedure. This investigation is particularly useful in persistent mono articular arthritis, e.g. in tuberculosis.
AN ARTHROGRAM can also be used to visualize the meniscus or to demonstrate knee-joint rupture.
RADIOISOTOPE BONE SCAN is useful in demonstrating malignant deposits. Increased uptake also occurs around osteoarthritic joints and also in inflammatory arthropathies, but these abnormalities can usually be distinguished from malignant disease.
HISTOCOMPATIBILITY ANTIGEN HLA-B27 is found in 96% of patients with ankylosing spondylitis and only 5% of normal people in the UK. There are marked differences between the incidence of the antigen in different populations that roughly parallel the frequency of ankylosing spondylitis. In addition, about 60% of patients with Reiter’s disease are B27 positive.
M R I SCANNING is useful for the detection of mechanical problems in joints, for example a torn meniscus or ruptured cruciate ligament in the knee or a rotator cuff tear in the shoulder. It is also useful to detect avascular necrosis for example in the hip joint, and is replacing myelography for the detection of spinal disease.

Typical synovial fluid changes in some rheumatic diseases.

Typical synovial fluid changes in some rheumatic diseases.

Investigation

Investigations are often unnecessary in patients with rheumatic complaints. In patients with tennis elbow, osteoarthritis and many other conditions, the diagnosis can be made on the basis of history and examination findings. There are no diagnostic tests in osteoarthritis and tests are only requested to exclude some other condition.

ERYTHROCYTE SEDIMENTATION RATE (ESR) AND C-REACTIVE PROTEIN (CRP)
These provide a guide to the activity of inflammation and are characteristically raised in inflammatory conditions such as rheumatoid arthritis but are normal in osteoarthritis.

Investigations in rheumatic diseases.

Investigations in rheumatic diseases.

TESTS FOR RHEUMATOID FACTOR

Rheumatoid factors are autoantibodies found in the serum, usually of the IgM class, which are directed against human IgG. They are detected by agglutination of either latex particles (the latex test) or sheep red cells (the Rose- Waaler test) (Fig. 8.2). The major value of rheumatoid factor tests is in the diagnosis of rheumatoid arthritis. The latex test is quicker and easier to perform; it is more sensitive, and therefore more often positive, but is less specific than the sheep red cell test.

ANTINUCLEAR ANTIBODIES 

Antinuclear antibodies in the serum are detected using immunofluorescent staining of the nuclei of a tissue such as rat liver or human cells in tissue culture. A low titre of less than 1 : 40 is weakly positive and of little significance. Antibodies to other nuclear antigens A variety of antinuclear antibodies have been described with particular disease associations that are summarized. It seems likely that the pattern of disease is determined by the nature of the autoantibodies produced.

The rheumatoid factor test using latex particles.

The rheumatoid factor test using latex particles.

Conditions in which rheumatoid factor is found in the serum.

Conditions in which rheumatoid factor is found in the serum.

Immunofluorescent test for antinuclear antibodies.

Immunofluorescent test for antinuclear antibodies.

Antibodies against double-stranded DNA (dsDNA) These can be detected using the Farr test, a radioimmunoassay measuring the percentage antibody binding of added labelled dsDNA. Antibodies are found in about 50% of cases of systemic lupus erythematosus (SLE) but seldom in any other condition. They are therefore a much more specific test than antinuclear antibodies. They are also associated with more severe disease and renal involvement.

Conditions in which antinuclear antibodies are found in the serum.

Conditions in which antinuclear antibodies are
found in the serum.

Serum antinuclear antibodies and their clinical associations.

Serum antinuclear antibodies and their clinical associations.

Antibodies against extractable nuclear antigen (EN A)

IgG class antibodies against soluble nuclear antigens are characteristic of mixed connective-tissue disease, the overlap syndrome described on p. 405, but are also found in patients with SLE.

Clinical features

HISTORY

The main features are listed and some of these points are discussed below.

Background information

This may be helpful in assessing the type of arthritis. For example:

AGE. Osteoarthritis commonly presents at 50 years of age.
SEX. Rheumatoid arthritis is commoner in women, whilst Reiter’s syndrome is commoner in men.
RACE. Some arthropathies are particularly associated with diseases occurring in particular races, e.g. in sickle cell disease.
OCCUPATION. This can be an important factor in softtissue rheumatism or osteoarthritis.

Rheumatological terms.

Rheumatological terms

Main features in the history of a patient with arthritis.

Main features in the history of a patient with
arthritis.

Joint pain

The type of pain is of little help as all joint pains feel much the same to the patient. The following points are of some value:
1 Duration. For example, a long history is suggestive of rheumatoid arthritis, whilst a short history may suggest gout.
2 Onset. Some conditions like gout start suddenly. 3 Precipitating factors. For example, injury may lead to osteoarthritis, diuretic therapy can precipitate gout, and a sore throat precedes rheumatic fever.

Characteristics

(a) Site of the pain-this usually indicates the site of the pathology although hip disease may present with knee pain and pain in the arm or leg may arise from the neck or back.
(b) Radiation-a lesion of the cervical or lumbar spine will give pain in the distribution of the affected roots.
(c) Severity-excruciating pain is characteristic of acute gout.
(d) Aggravating and relieving factors-inflammatory joint pains are usually better with activity; patients are stiff and painful after rest. Mechanical problems are made worse by activity and relieved by rest.
(e) Diurnal variation-pain due to inflammation is characteristically worst in the mornings and improves during the day.
(d) Episodic arthritis-the frequency, regularity and duration of attacks should be noted.

Other joint symptoms

Enquire about:
MORNING STIFFNESS. This is characteristic of inflammatory arthropathies. The duration of stiffness gives some guide to the activity of the inflammatory process.

JOINT SWELLING. This always indicates local disease.
PATTERN OF JOINT INVOLVEMENT. For example, recurrent attacks in the big toe are suggestive of gout.
CLICKING AND CREAKING OF THE JOINT. These are not important and can be felt in normal joints. DISABILITY. This is a very individual problem, depending on joints affected and the demands made upon them. It is however important in determining the right approach to treatment.

Associated non-articular symptoms

Nodules or a pleural effusion may be a clue to the diagnosis of rheumatoid arthritis. The cause of a particular arthritis may also lie in disease of other systems such as psoriasis or ulcerative colitis.

Past medical history

A history of trauma or of some other disease like psoriasis may be helpful.

Family history

Some conditions run in families, e.g. osteoarthritis, ankylosing spondylitis and gout. Patients with psoriatic arthritis do not necessarily have psoriatic skin lesions but may give a family history of psoriasis.

 Social history

The occupation of the patient may have a bearing on the arthritis. In addition, the development of a chronic arthritis has a major influence on the life-style of both patient and family.

Treatment record

A record of the previous treatments tried and their success is important for the future management.

EXAMINATION OF JOINTS
There are three stages in the examination of an individual joint:

1 Look at it
2 Feel it
3 Move it
Inspection will reveal swelling, deformities, changes in the overlying skin (e.g. erythema) and abnormalities of the surrounding structures, e.g. wasting of muscle or swelling of bursae.
Palpation will reveal the nature of any observed swelling as well as the presence or absence of warmth and tenderness, which are cardinal signs of inflammation. There are three types of joint swelling:

1 A hard or bony swelling
2 An effusion
3 Synovial thickening
The presence of an effusion can be demonstrated by fluctuation or by a patellar tap in the knee joint. A firm nonfluctuant swelling is characteristic of synovial thickening. Movement of a joint may produce pain or crepitusa sensation of grating that is characteristic of osteoarthritis. The range of movement should be noted. Excessive
abnormal movement is called instability. Posture and gait should also be assessed.

Movement of joints is described in terms of flexion, extension, abduction, adduction and rotation. Deformities are described as valgus (like knock knees) or varus (like bow legs). A system of examination should be followed so that no joint is missed.

Rheumatology and bone disease

RHEUMATOLOGY

Introduction

Rheumatology is concerned with medical disorders of the locomotor system, which can be divided into three categories: arthritis, back pain and soft-tissue rheumatism. Most of these diseases are seen worldwide, although the prevalence of individual conditions varies. Rheumatic diseases constitute about 20% of the work-load of a primary- care physician.

The normal joint

The structure of a typical synovial joint is shown. The joint itself is made up of two articulating bone urfaces, each covered with articular cartilage, and a fibrous capsule lined by synovium. The space within the joint is filled with synovial fluid, which acts as a lubricant. Inflammation of the above structures is described as arthritis. The term arthropathy is sometimes used to describe joint disease of any type. The joint is surrounded by so-called ‘soft tissues’, including tendons, ligaments and bursae. The specialized junction of tendon and bon is called an enthesis; this can also become inflamed.

typical synovial joint.

typical synovial joint.

Rheumatological terminology

The main terms used in rheumatology are outlined In Information box