Chapter 42. Miscellaneous Forms of Vasculitis

Essentials of Diagnosis

• Rheumatoid vasculitis usually occurs in patients with severe, long-standing, nodular, destructive rheumatoid arthritis, especially when the joint disease is “burnt out.”
• Palpable purpura, cutaneous ulcers (particularly in the malleolar region), digital infarctions, and peripheral sensory neuropathy are common manifestations.
• Tissue biopsy helps establish the diagnosis of rheumatoid vasculitis. Nerve conduction studies can identify involved nerves for biopsy. Muscle biopsies should be performed simultaneously with nerve biopsies to increase the diagnostic yield of the procedure.

General Considerations

Rheumatoid vasculitis (RV) is a medium-vessel vasculitis that occurs in patients with “burnt-out” but previously severe rheumatoid arthritis (RA). The typical patient has long-standing RA characterized by rheumatoid nodules, destructive joint disease, and high titers of rheumatoid factor. The diagnosis of RV should be considered in any patient with RA in whom new constitutional symptoms, skin ulcerations, serositis, digital ischemia, or symptoms of sensory or motor nerve dysfunction develop. RV resembles polyarteritis nodosa because it leads to multiorgan dysfunction in the skin, peripheral nerves, gastrointestinal tract, and other organs. Manifestations of RV, which resemble those of polyarteritis nodosa, include cutaneous ulcerations, digital ischemia, mononeuritis multiplex, and mesenteric vasculitis (see Chapter 35).

Pathogenesis

Immune complex deposition and antibody-mediated destruction of endothelial cells both appear to contribute to RV. Certain HLA-DR4 alleles that predispose patients to severe RA may also heighten patients’ susceptibility to RV. Cigarette smoking increases the risk of RV and has a synergistic interaction in this regard with antibodies to cyclic citrullinated peptides (anti-CCP antibodies). However, the inciting events leading to the development of RV among patients with previously destructive arthritis are not known. Factors in addition to vasculitis (eg, diabetes mellitus, atherosclerosis, and hypertension) likely play an important adjunctive role in promoting vascular occlusion, but the central issue in RV is necrotizing inflammation of blood vessels.

Clinical Findings

Symptoms and Signs

Skin

Dermatologic findings, the most common manifestation of RV, may include palpable purpura, cutaneous ulcers (particularly in the malleolar region), and digital infarctions (Figure 42–1).

Nervous System

A peripheral sensory neuropathy is a common manifestation of RV. A mixed motor-sensory neuropathy or mononeuritis multiplex may also be seen. Central nervous system manifestations (such as strokes, seizures, and cranial nerve palsies) are considerably less common.

Eyes

Retinal vasculitis as a manifestation of RV is common but frequently asymptomatic. Necrotizing scleritis and peripheral ulcerative keratitis (Figure 42–2) pose threats to vision and require aggressive immunosuppressive therapy.