Chapter 097. Paraneoplastic Neurologic Syndromes (Part 6)

Paraneoplastic Encephalomyelitis and Focal EncephalitisThe term encephalomyelitis describes an inflammatory process with multifocal involvement of the nervous system, including brain, brainstem, cerebellum, and spinal cord. It is often associated with dorsal root ganglia and autonomic dysfunction. For any given patient, the clinical manifestations are determined by the area or areas predominantly involved, but pathology almost always reveals abnormalities (inflammatory infiltrates, neuronal loss, gliosis) beyond the symptomatic regions. ...
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Chapter 097. Paraneoplastic Neurologic Syndromes (Part 6) Chapter 097. Paraneoplastic Neurologic Syndromes (Part 6) Paraneoplastic Encephalomyelitis and Focal Encephalitis The term encephalomyelitis describes an inflammatory process withmultifocal involvement of the nervous system, including brain, brainstem,cerebellum, and spinal cord. It is often associated with dorsal root ganglia andautonomic dysfunction. For any given patient, the clinical manifestations aredetermined by the area or areas predominantly involved, but pathology almostalways reveals abnormalities (inflammatory infiltrates, neuronal loss, gliosis)beyond the symptomatic regions. Several clinicopathologic syndromes may occuralone or in combination: (1) cortical encephalitis, which may present as epilepsiapartialis continua; (2) limbic encephalitis, characterized by confusion, depression,agitation, anxiety, severe short-term memory deficits, partial complex seizures,and dementia; the MRI usually shows unilateral or bilateral medial temporal lobeabnormalities, best seen with T2 and fluid-attenuated inversion recoverysequences, and occasionally enhancing with gadolinium; (3) brainstemencephalitis, resulting in eye movement disorders (nystagmus, opsoclonus,supranuclear or nuclear paresis), cranial nerve paresis, dysarthria, dysphagia, andcentral autonomic dysfunction; (4) cerebellar gait and limb ataxia; (5) myelitis,which may cause lower or upper motor neuron symptoms, myoclonus, musclerigidity, and spasms; and (6) autonomic dysfunction as a result of involvement ofthe neuraxis at multiple levels, including hypothalamus, brainstem, and autonomicnerves (see autonomic neuropathy). Cardiac arrhythmias, postural hypotension, orcentral hypoventilation are frequent causes of death in patients withencephalomyelitis. Paraneoplastic encephalomyelitis and focal encephalitis are usuallyassociated with SCLC, but many other cancers have also been reported. Patientswith SCLC and these syndromes usually have anti-Hu antibodies in serum andCSF. Anti-CV2/CRMP5 antibodies occur less frequently; some of these patientsmay develop chorea or uveitis. Antibodies to Ma proteins are associated withlimbic, hypothalamic and brainstem encephalitis and occasionally with cerebellarsymptoms (Fig. 97-3); some patients develop hypersomnia, cataplexy, and severehypokinesia. MRI abnormalities are frequent, including those described withlimbic encephalitis and variable involvement of the hypothalamus, basal ganglia,or upper brainstem. Antibodies to NR1/NR2 subunits of the NMDA receptorassociate with a severe, potentially lethal, but treatment-responsive encephalitis.The affected patients are young women who develop combinations of psychiatricsymptoms, seizures, dyskinesias, stupor and hypoventilation. The oncologicassociations of these antibodies are shown in Table 97-2. Figure 97-3 MRI and tumor of a patient with anti-Ma2-associated encephalitis.Panels A and B are fluid-attenuated inversion recovery MRI sequences showingabnormal hyperintensities in the medial temporal lobes, hypothalamus and upperbrainstem. Panel C corresponds to a section of the patients orchiectomy incubatedwith a specific marker (Oct4) of germ-cell tumors. The positive (brown) cellscorrespond to an intratubular germ-cell neoplasm.