|Rheumatology 3 – The Spectrum of inflammatory Arthritis
Introduction to and overview of Rheumatology
To recognise the major features which distinguish between different types of inflammatory arthritis
To appreciate the ways in which rheumatic disease integrates with General Medicine and orthopaedics
Rheumatic disease involves disease of joints, this means it includes: arthritis, muscle disease, bone disease, and soft tissue rheumatism.
Autoimmune diseases consist of the following:
Arthritis has many causes…
It can be autoimmune, and this is in fact the most common cause. Autoimmune diseases are in fact the most common disorders generally – they include diabetes, multiple sclerosis, and inflammatory bowel disease, for example.
Can be due to seronegative spondyloarthropathies (discussed in a later lecture).
Arthritis can be associated with infection of the joints.
It may occur due to degeneration (of the cartilage – not the bones).
Crystal causes (such as gout*) can also cause arthritis.
*Gout is a disease in which a defect in uric acid metabolism causes an excess of the acid and its salts (urates) to accumulate in the bloodstream and the joints respectively. It results in attacks of acute gouty
This is a chronic erosive destructive arthritis caused by synovial proliferation – this is proliferation of the synovial membrane which lines synovial joints.
It is a major cause of disability in relatively young people – it can affect anyone from their teens until about their 60’s or 70’s – therefore, it is not just a disorder of old people.
Significant advances in drug therapy for rheumatoid arthritis have been made (many of which were developed at Imperial College).
Important to note is that RA may present to a non-rheumatologist with non-articular features, for example RA is known to involve the haematologic, cardiovascular, and respiratory systems. Also, the drugs used to treat RA or their effects (for example immunosuppression) may influence other diseases or their treatment.
Systemic lupus erythematosus
This is a systemic disease characterised by antinuclear antibodies and a malar rash (the rash is induced by UV light insults to the skin).
This condition affects 1 in 2,000 people, and nine times as many females than males. It is most prevalent in those aged between 13 and 50 (it is therefore a disease that can occur in women who are of a child-bearing age – this is very important).
Mild symptoms include…
Raynaud’s disease (this is a condition of unknown origin in which the arteries of the fingers are unduly reactive and enter spasm (angiospasm or vasospasm) when the hands are cold. This produces attacks of pallor, numbness, and discomfort in the fingers). This condition affects about 3% of the population, and is more likely to occur in patients who have SLE; however, if you already have Raynaud’s disease, you are unlikely to get SLE.
Pleurisy (inflammation of the pleura of the lungs).
Rashes may develop.
Severe symptoms include…
Nephritis (inflammation of the kidneys).
There may be cerebral involvement which is associated with many complications.
Diagnosis of the condition involves assessing the constellation of clinical features present including the symptoms given above and also looking at levels of ANA (antinuclear antibodies), leucopenia (a decreased number of white blood cells), and low levels of complement present in the blood.
Treatment of SLE involves the use of steroids (commonly prednisolone) – the steroids are life saving here as they prevent serious complications (such as renal failure) occurring, anti-malarial drugs (such as hydroxychloroquine) – it is not known why this drug works, and also cytotoxic drugs (these are immunosuppressant drugs).
NB: don’t need to know about last 4.
Can affect spine which is negative for rheumatoid factor.
Can mimic mechanical back pain
Strong association between HLA B27
Arthritis occurring after an infection.
Enteritis or urethritis
Commonly presents with knee involvement
A progressive, chronic disease that affects young men
Ankylosis is a pathological fusion of the bones across a joint space, either by bony tissue (bony ankylosis) or by shortening of connecting fibrous tissue (fibrous ankylosis). Ankylosis is a complication of prolonged joint inflammation and may occur in chronic infection.
Sacroiliitis and calcification of paraspinous ligaments
There are two types of psoriatic arthritis. The first is polyarticular (which means that many joints are affected – generally more than 5 joints). The other is pauciarticular (which means that few joints are affected – generally 4 or less).
Psoriasis is a chronic skin disease in which scaly pink patches form on the elbows, knees, scalp and other parts of the body. Psoriatic arthritis is an arthritis which is associated with psoriasis. It (psoriatic arthritis) only occurs in a small minority of patients with psoriasis, but it may be disabling and very painful.
This form of arthritis is rheumatoid arthritis-like (i.e. it is seronegative), and is also described as being arthritis mutilans (meaning there is a rapid destruction of the joints involved).
This is a form of arthritis which has a very variable pattern that is associated with inflammatory bowel diseases, for example ulcerative colitis, and Crohn’s syndrome.
This type of arthritis is less common than psoriatic arthritis.
The significance of spondyloarthropathies in medicine
Women have lower levels of testosterone and are therefore have a lower rate of bone tissue synthesis. Therefore, men are more at risk of these spondyloarthropathies.
Spondyloarthropathies can mimic mechanical back pain.
The radiological signs may be absent in women with AS (as they are not good at making bone, there bones may not be calcified at this stage).
Enteropathic arthritis may be the presenting sign of inflammatory bowel disease.
Finally, reactive arthritis presenting as a monoarthritis (inflammation of one joint) may mimic trauma (such as a swollen knee following surgery), or septic arthritis.
Associated with infection
Bacterial: septic arthritis (staph, commonest)
viral: Parvovirus, Rubella, EBV
Loss of proteoglycan from cartilage (age, trauma)
Synovitis occurs secondary to cartilage damage causing swelling and pain
Fibrillation, thinning and loss of cartilage
Reactive hyperplasia around joint margin. (increased production of growth in normal cells)
Weight-bearing joints, DIPs (Heberden’s nodes) and CMC of the thumb are all affected
X-rays: loss of joint space, osteophytes, sclerosis
The significance of OA in medicine…
OA has a differential diagnosis from RA…
The joint distributions are different (joint involvements are different).
OA has normal ESR and CRP levels.
X-rays can also be used to distinguish OA from RA, and have been described earlier in this lecture.
It is the commonest cause of disability.
Gout (uric acid)
1st MTP joint of great toe
Tophi are present (deposits of uric acid under the skin)
History of diuretics
Pseudogout ( calcium pyrohosphate)
Occurs in osteoarthritis, hyperparathyroidism, haemochromatosis
Largely caused by calcium pyrophosphate deposits. Just as common as gout.
Other areas within rheumatology
Muscle disease (with neurologists)
Polymyositis (this is a generalised disease of the muscles that may be acute or chronic. It particularly affects the muscles of the shoulder or hip girdles, which will be weak and tender to touch. The condition is relieved using corticosteroid drugs).
Polymyalgia rheumatica (this is a rheumatic disease causing aching and progressive stiffness of the muscles of the shoulders and hips after inactivity. This condition is particularly associated with a raised ESR. Again, this condition can be effectively treated using corticosteroid therapy)
Bone disease (with endocrinologists)
Osteoporosis – this is the thinning of bones due to the loss of the bone matrix. This condition is measurable using DEXA (dual-energy X-ray absorptiometry) scanning, which measures bone density based on the proportion of a beam of photons that passes through the bone. The condition is also treatable using drugs such as HRT and biphosphonates, and you should also recall that it is a disease that affects far more women than men.
Osteomalacia – this is the softening of bones caused by a deficiency of vitamin D, either from a poor diet or lack of sunshine, or both. It is the adult counterpart of rickets.
Paget’s disease – this is a chronic disease of bones, occurring in the elderly and most frequently affecting the skull, backbone, pelvis, and other long bones. Affected bones become thickened and their structure disorganised – hence X-rays reveal patchy sclerosis. This condition can be treated using biphosphonates and calcitonin.
Soft tissue rheumatism (with orthopaedics)
“Frozen shoulder” (the details of this has been covered in limb anatomy), tennis elbow (which is basically due to lateral epicondylitis), and golfer’s elbow (which is basically due to medial epicondylitis).