Rheumatological emergencies

Acute monoarthritis

Although a patient with established RA may present with an acutely painful, hot, swollen joint that is due to the underlying condition, consideration of septic arthritis is important. Patients with RA are two to three times more susceptible to septic arthritis than matched controls. The risk is approximately twofold higher again in RA patients on TNF-α inhibitors compared with RA patients on conventional DMARDs. Septic arthritis must be considered in a patient with RA who has acute monoarthritis out of keeping with their disease activity.

Cervical spine involvement

Cervical spine involvement in RA is common with a prevalence of up to 80%. Cervical spine involvement may manifest as atlanto-axial subluxation (most commonly anterior movement on the axis) or subluxation of lower cervical vertebrae. Either of these can result in cervical myelopathy.

Cervical spine subluxation is often asymptomatic. The most common symptom is neck pain that may radiate towards the occiput. Other suggestive symptoms include sensory loss in hands or feet, paraesthesia or weakness in the distribution of cervical nerve roots, and slowly progressive spastic quadriparesis.

Important ‘red flags’ suggesting cervical myelopathy are listed in Box 14.1.1 .

Rheumatoid vasculitis

Vasculitis in RA can occur in both small- and medium-sized vessels. Patients typically have long-standing, aggressive joint disease. This presentation, although important, is becoming less frequent due to the development of effective RA treatment.

Clinical features

Rheumatoid vasculitis presentations are varied and non-specific. Patients frequently have constitutional symptoms and fatigue. One of the most common manifestation of medium vessel RA vasculitis includes deep skin ulcers on the lower limbs, digital ischaemia and gangrene. Palpable purpura is a manifestation of small vessel RA vasculitis. Mononeuritis multiplex is another frequent presentation resulting from vasculitic infarction of the vasa nervorum, which typically has an acute onset.

Medium vessel rheumatoid vasculitis may also cause organ infarction and necrosis and mimics polyarteritis nodosa (PAN) with vasculitis of the renal arteries and, less commonly, the mesenteric circulation. Pericarditis may accompany rheumatoid vasculitis, but coronary vasculitis is rare. Ocular manifestations include episcleritis and peripheral ulcerative keratitis. Central nervous system (CNS) involvement is rare.

Investigations and diagnosis

Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) are elevated in rheumatoid vasculitis. Rheumatoid factor titre is typically elevated in rheumatoid vasculitis, although this is a non-specific finding. Rheumatoid vasculitis in the absence of rheumatoid factor is rare. Anti-citrullinated protein antibody (anti-CCP) may be positive in rheumatoid vasculitis, but once again, is a non-specific finding. Check a full blood count, urea and electrolytes, and a midstream urine specimen for active urinary sediment, including abnormal red cells or casts, proteinuria, as well as infection. In the work-up of vasculitis, it is also important to exclude infections that may mimic vasculitis. These include hepatitis B and C, human immunodeficiency virus (HIV) and syphilis, as well as a basic infection screen.

Further investigations are directed at the relevant organ system involved usually after specialist consultation:

• skin biopsy for cutaneous involvement

• nerve conduction studies/electromyography (EMG) for mononeuritis multiplex

• sural nerve biopsy for mononeuritis multiplex

• renal biopsy for deranged renal function or active urinary sediment

Angiography findings are non-specific and not always diagnostic.

Management

Systemic rheumatoid vasculitis has a poor prognosis without immune-suppressive therapy. Urgent rheumatology consultation is required, as treatment usually consists of high-dose corticosteroids as well as cyclophosphamide or, a DMARD, often necessitating hospital admission.

Pulmonary disease

Pulmonary manifestations include pleural-based disease, such as pleurisy or pleural effusions, or parenchymal disease, such as interstitial lung disease (the most common manifestation), organizing pneumonia and rheumatoid nodules. Caplan’s syndrome occurs when RA is associated with pneumoconiosis. Important differential diagnoses include infection due to immune suppression, treatment-related toxicity, such as methotrexate-induced pneumonitis, and other medical co-morbidities, including chronic obstructive pulmonary disease.

Parenchymal disease documented on chest x-ray or high-resolution CT requires specialist treatment.

Cardiac disease

Pericarditis occurs in 30% of RA patients based on electrocardiogram and/or echocardiography, but less than 10% have clinical features. It generally presents when there is active joint and other extra-articular disease, and management consists of NSAIDs or prednisolone.

Myocarditis is a rare manifestation of RA. It may be granulomatous and, depending on its location, can produce valvular (especially mitral) incompetence or conduction defects. It is investigated with troponin, cardiac MRI and/or cardiac biopsy.

Sjögren syndrome

Sjögren syndrome may present in a primary form as a systemic disease, but can also occur secondary to RA and other connective tissue disorders. The classic symptoms are dry gritty eyes, dry mouth or both. Treatment is usually symptomatic in patients with no other features.

Felty syndrome

Felty syndrome is characterized by seropositive RA, splenomegaly and neutropaenia. There may be other cytopaenias, as well as leg ulcers, and infection is a risk.