44 - Paraneoplastic Neurologic Syndromes

Abstract

Paraneoplastic neurologic syndromes are immune-mediated disorders occurring in patients with cancer. Identification of the paraneoplastic origin of a patient's symptoms is important because the neurologic symptoms often develop before the cancer diagnosis is known. The diagnosis of a paraneoplastic neurologic disorder is based on the type of neurologic syndrome, the detection of an associated tumor, and the presence or absence of specific serum and/or cerebrospinal fluid antibodies. Although patients can have a paraneoplastic syndrome without antibodies, it is important to understand the significance of the antibodies. There are antibodies that are highly specific for the paraneoplastic origin of the neurologic symptoms and are not or rarely found in patients with similar neurologic disorders without cancer. These antibodies serve as markers of the paraneoplastic origin of neurologic symptoms and for the presence of specific tumor types. Other antibodies target neuronal cell surface proteins. The disorders in which these antibodies are found occur with or without cancer, and thus the antibodies are markers of the neurologic syndromes. Although the presence of these antibodies does not distinguish between a paraneoplastic or nonparaneoplastic etiology, some antibodies tend to associate with one or a few cancer types when the disorder is paraneoplastic. The approach to treatment of paraneoplastic neurologic syndromes and the expected response is largely based in the underlying immune mechanism. Some syndromes are resistant to treatment, whereas others are very responsive and patients can have full or near complete recovery. Early diagnosis and institution of immunotherapy (and tumor treatment when indicated) are important for optimizing outcomes.