Essential facts

The inflammatory arthritides, the autoimmune rheumatic diseases, and their treatment may have significant effects outside the bones and joints. Table 18.1 gives some examples and outlines the systems that might be affected. Some of this information is expanded on in other chapters of the book. This section provides a brief overview of problems to consider in everyday practice.

Table 18.1 Summary of systemic complications of rheumatic diseases and their management

Systemic features

Many inflammatory rheumatic diseases are associated with significant systemic features, which may be responsible for weight loss, malaise, weakness and fever. This makes the differential diagnosis wider, with concerns over whether or not patients have malignancy, infection or drug toxicity.

Cutaneous problems

The most common manifestations are drug reactions; typically they will resolve on discontinuing the offending agent. Patients with rheumatic disease are often treated with combinations of drugs for their main condition as well as associated co-morbidity. It may be necessary to find the offending drug by sequentially stopping the most recently prescribed drug, the next most recently prescribed drug, and so on. Some agents such as allopurinol are well known to cause a rash, if given in too high a dose, or in standard doses, for example the anti-tumour necrosis factor (TNF) agents commonly cause an injection-site reaction. For most drugs, however, the skin rash is unpredictable, and varies from trivial to life-threatening. Many rheumatic diseases are associated with rashes; systemic lupus erythematosus (SLE) is the most typical, resulting in a photosensitive eruption on light-exposed skin. Psoriatic rashes can be very obvious if present on the trunk or arms, but subtle and worth looking for in the hairline, natal cleft or umbilicus. The changes to skin in scleroderma are of thickening and discoloration, often accompanied by Raynaud’s phenomenon. Vasculitic rashes are not specific for individual conditions; purpura is a common manifestation, but nail-edge lesions and splinter haemorrhages can also occur.

Neurological problems

Long-standing rheumatoid arthritis (RA) predisposes to sensory peripheral neuropathy (glove and stocking distribution). Chronic peripheral nerve injury may occur from synovitis in the wrist compressing the median nerve and resulting in carpal tunnel syndrome. Acute cord compression is a feature of long-standing RA with instability of the cervical spine, due to erosive disease of the odontoid peg, ischaemic pressure from pannus, and compounded by instability of the atlanto-axial articulation. Mononeuritis multiplex can arise as a result of different forms of vasculitis causing nerve injury. The brain may be at risk in SLE as a result of ischaemia through vasculitis, clotting of vessels by anti-cardiolipin antibody syndrome, or the vasculopathy of SLE. Mechanical problems in the spine may lead to nerve or cord compression depending on the level of injury and its severity. Careful evaluation of the nervous system is important in any patient with back pain, especially if they have a history of pain or numbness in a peripheral limb.

Pulmonary problems

Lung alveolitis and fibrosis are common long-term complications of RA, SLE and scleroderma (especially diffuse cutaneous scleroderma). The pleural sac may be inflamed as part of a generalized polyserositis. In SLE and the vasculitides this is often acute with painful pleuritic pain, but in RA it is often more insidious leading to quite large pleural effusions and, eventually, to breathlessness on exertion. Rheumatoid lung nodules may be seen as isolated peripheral shadows on a chest radiograph, raising suspicion of tumour; they may even liquefy in the centre, giving rise to a fluid level and concern about possible abscess. Occasionally lung nodules occur prior to the onset of joint symptoms, causing considerable diagnostic confusion. Patients with systemic vasculitis affecting small vessels may develop alveolar inflammation and haemorrhage, typically in microscopic polyangiitis and anti-glomerular basement membrane disease (Goodpasture syndrome). Haemorrhage may also occur in granulomatosis with polyangiitis and eosinophilic granulomatosis with polyangiitis (Churg–Strauss syndrome); however, diffuse infiltrates and/or nodules are more common. Bronchial and tracheal ulceration and inflammation leading to stenosis are characteristic findings in granulomatosis with polyangiitis. Patients with Sjögren syndrome can develop dryness in the trachea and bronchi, leading to cough, and predisposing to chest infections through impaired clearance of secretions.