Paraneoplastic neurological syndromes – essential characteristics, classification, etiopathogenesis and diagnostics
Abstract
Paraneoplastic neurological syndromes (PNS) are a heterogeneous group of disorders and may affect any part of the nervous system, neuromuscular junction and muscles. Evidence is increasing that most PNS are immune – mediated.
The current concept is that the expression of neuronal proteins by a tumor provokes an immune response against both the tumor and the nervous system. A patient produces tumor-directed antibodies known as onconeural antibodies and because of antigenic identity, these onconeural antibodies attack components of the nervous system as well.
Based on the clinical syndrome, the type of antibody, and the resence or absence of cancer, patients are classified as having a definite or possible PNS. Onconeural antibodies are classified either as well characterized with a strong cancer association or partially characterized.
Some other antibodies may occur in both cancer- and non-cancer-associated syndromes. Diagnosis of PNS is important because it can lead to the early detection of the tumor.
The symptoms of PNS occur in approximately two thirds of patients before the presence of systemic cancer is known. Treatment of the tumor is the most effective step in controlling or at least stabilizing the neurological disorder.