Classic polyarteritis nodosa (PAN) is characterized by necrotizing vasculitis of medium and small muscular arteries. The lesions are segmental, and aneurysms may develop, which are detectable by angiography. Mononeuritis multiplex, a painful vasculitic neuropathy involving peripheral motor or sensory nerves, may be a presenting feature. CNS lesions can also occur. Renal involvement is common and is often associated with hypertension due to glomerular ischemia. Gastrointestinal disease with infarction of the viscera is also common. PAN may be limited to a single organ, such as the appendix, uterus, or testes. Although most cases of PAN are idiopathic, hepatitis B and C viral infections as well as hairy cell leukemia have been linked to its onset. Biopsy of involved tissues or organs is helpful in confirming the diagnosis.
The mean age of onset of PAN is in the fifth and six decades of life, with men affected more often than women. Survival in patients with untreated PAN is poor. However, most patients can be treated with a combination of corticosteroids and an immunosuppressive drug such as cyclophosphamide. Therapy appears to improve disease control and long-term outcomes. Systemic antivirals may be helpful in treating PAN related to hepatitis B or C. See BCSC Section 9, Uveitis and Ocular Inflammation.
Kawasaki disease, also known as mucocutaneous lymph node syndrome, is a condition associated with inflammation in the walls of medium-sized vessels throughout the body. The disease typically affects infants and young children. Patients often develop a persistent high fever, swollen lymph nodes, bilateral conjunctivitis, and truncal rash. A characteristic feature of Kawasaki disease is strawberry tongue—an extremely red, swollen tongue.
Although the disease is typically self-limited, it can lead to associated cardiovascular complications including coronary artery aneurysms, myocarditis, and dysrhythmias. Prompt treatment, which includes intravenous immunoglobulin and aspirin, reduces the potential for long-term complications.
Excerpted from BCSC 2020-2021 series: Section 1 - Update on General Medicine. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.