Update on Paraneoplastic Neurologic Disorders

Note:  very complicated condition/conditions/subsets of conditions and requires specialist consultation/s.

"When patients with cancer develop neurologic symptoms, common causes include metastasis, infections, coagulopathy, metabolic or nutritional disturbances, and neurotoxicity from treatments. A thorough clinical history, temporal association with cancer therapies, and results of ancillary tests usually reveal one of these mechanisms as the etiology. When no etiology is identified, the diagnosis considered is often that of a paraneoplastic neurologic disorder (PND). With the recognition that PNDs are more frequent than previously thought, the availability of diagnostic tests, and the fact that, for some PNDs, treatment helps, PNDs should no longer be considered diagnostic zebras, and when appropriate should be included in the differential diagnosis early in the evaluation."



"...Because of the common association of breast and gynecological cancers with PNDs, a mammogram and pelvic computed tomography (CT) scan or ultrasound should be carried out in all women with a suspected PND [28]. Whole-body PET scans may detect tumors that escape detection by other standard imaging methods [29, 30]. Men with symptoms of limbic and brainstem encephalitis should be examined for a testicular tumor, and young women should be examined for an ovarian teratoma that may appear as a benign cyst. In both instances, ultrasound and CT of the abdomen and pelvis are useful to identify tumors of the gonads and retroperitoneal space. For patients with classic PNDs, or those with less classic PNDs but who are positive for paraneoplastic antibodies, in whom a tumor is not found, periodic cancer screening should be considered. In general, a cancer will be identified within the first year of the PND, but there are rare instances when the expected type of tumor was demonstrated several years later."

CLINICAL CHARACTERISTICS

*Encephalomyelitis
*Cerebellar Degeneration (The most commonly associated tumors are SCLC, cancers of the breast and ovary, and Hodgkin's lymphoma.)
*Limbic and Brainstem Encephalitis (The most commonly associated cancers are SCLC, testicular germ-cell tumors, teratoma (usually of the ovary), thymoma, and Hodgkin's lymphoma)
* Encephalitides with Antibodies to Cell Surface or Synaptic Proteins
* Opsoclonus-Myoclonus (also known as 'dancing eyes') 
* Subacute Sensory Neuronopathy
* Subacute and Chronic Peripheral Neuropathies ( The development of peripheral nerve dysfunction in cancer patients is common, and in most patients is not paraneoplastic.)
* Paraneoplastic Vasculitis

* LEMS 
* Stiff-Person Syndrome  
* Paraneoplastic Visual Syndromes