Paraneoplastic disorders
Spread of the neoplasm to the nervous system (see Chapter 46).
Systemic metabolic and hemodynamic disturbances (Table 47.1).
Table 47.1
Cancer-related systemic disorders producing CNS symptomatology
| Metabolic/endocrine disorders | Potential etiology |
| Hepatic failure | Liver metastases |
| Hypoglycemia | Consumption of glucose by disseminated sarcoma |
| Hyponatremia | Syndrome of inappropriate ADH secretion |
| Hypercalcemia | Bone metastases/inappropriate parathyroid hormone production |
| Cushing syndrome | Inappropriate (ectopic) ACTH production |
| Wernicke–Korsakoff syndrome | Thiamine deficiency secondary to emesis |
| Vascular disorders | Potential etiology |
| Encephalopathy/infarction–hyperviscosity | Waldenstrom’s macroglobulinemia |
| Infarction–hypercoagulability state | Mucin-secreting adenocarcinomas |
| Infarction | Polycythemia rubra vera |
| Embolic infarction | Marantic endocarditis |
| Hemorrhage | Reduced coagulation factors in hepatic failure |
| Thrombocytopenia in bone marrow failure |
Infections secondary to immunosuppression produced by lymphoreticular neoplasms (Table 47.2).
Table 47.2
CNS infections particularly associated with lymphomas, leukemias, and myeloma
| Organism | Particular clinical association |
| Varicella zoster virus encephalitis | Hodgkin’s disease |
| Herpes simplex virus encephalitis | Hodgkin’s disease |
| Cytomegalovirus encephalitis | Acute lymphoblastic leukemia |
| Progressive multifocal leukoencephalopathy (JC papovavirus) | Various |
| Listeria infection | Post-splenectomy |
| Streptococcal meningitis | Post-splenectomy |
| Toxoplasmosis | Lymphoma |
| Cryptococcal meningoencephalitis | Various |
| CNS aspergillosis | Various |
Side-effects of cancer therapy (Table 47.3).
Table 47.3
CNS side-effects of cancer treatment
Radiotherapy
Encephalopathy
Delayed myelopathy
Hypothalamic/pituitary disturbances
Oncogenesis – mainly meningioma, sarcoma, glioma
Chemotherapy
Encephalopathy and/or myelopathy (particularly after BCNU, L-asparaginase, intrathecal methotrexate)
Cerebellar disorder (cytosine arabinoside)
Production of antibodies that simultaneously target onconeural antigens on neurons and neoplastic cells (Table 47.4), which is the subject of this chapter.
Table 47.4
Immunogenic paraneoplastic disorders affecting the nervous system
