[Autoimmune reactions and paraneoplastic syndromes].

CLINICAL ISSUE: Autoimmune disorders of the central nervous system (CNS) are common but are also a heterogeneous group of diseases. The most common form is multiple sclerosis (MS), others are clinically isolated syndrome (CIS), acute demyelinating encephalomyelitis (ADEM) and neuromyelitis optica spectrum disorders (NMOSD). Paraneoplastic syndromes are rare and tumor-associated, they are not induced by direct invasion of tumor tissue but by tumor-associated autoantibodies mostly against specific CNS proteins, e. g. limbic encephalitis and paraneoplastic cerebellar ataxia or degeneration. DIAGNOSTICS, STANDARD RADIOLOGICAL METHODS, PERFORMANCE AND ACHIEVEMENTS: The correct diagnosis of autoimmune and paraneoplastic syndromes can still be challenging. In addition to the patient history, clinical examination and blood as well as cerebrospinal fluid (CSF) tests, magnetic resonance imaging (MRI) is gaining importance in the diagnostics. It is important not only in primary diagnostics but also in follow-up and therapy monitoring, especially in MS with specific therapies to detect therapy complications, such as progressive multifocal leukoencephalopathy as early as possible. In paraneoplastic syndromes MRI can also be an important component in the diagnostics but can also initially be negative and typical signal changes become visible only in follow-up scans. PRACTICAL RECOMMENDATIONS: In paraneoplastic syndromes the correct diagnosis is based on laboratory tests for specific autoantibodies in serum and CSF. TREATMENT: The treatment of autoimmune and paraneoplastic disorders of the CNS ranges from steroids and immunosuppressive agents to plasmapheresis, depending on the specific disorder.