- Last edited on June 1, 2023
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Psychiatric Manifestations of Paraneoplastic Disorders
Primer
Paraneoplastic disorders can lead to severe psychiatric and behavioural symptoms. Paraneoplastic limbic encephalitis (PLE) is a rare neurological syndrome associated with cancer, and selectively affects limbic system structures, including the hippocampus, hypothalamus, and amygdala.[1] The encephalitis is caused by an altered immunologic response to a malignancy that has antigens that resemble limbic antigens. The inflammatory response, however, occurs away from the original neoplasm site.[2]
See main article: Autoimmune Encephalitis
Autoantibodies
The autoantibody response can be psychiatric in nature, and includes:
- NMDAR-antibody encephalitis, associated with ovarian teratomas in younger women
- Ophelia syndrome, associated with surface-directed mGluR5-antibodies, seen in patients with Hodgkin’s lymphoma
- Anti-neuronal nuclear antibody-1 (ANNA-1), also known as Hu paraneoplastic encephalomyelitis, associated with small cell lung cancer in 75% of cases (other tumours include lung, prostate, breast, bladder, GI tract, ovary, neuroendocrine, unknown origin), most commonly in men.
- AMPA receptor antibodies, associated with lung, breast, thymus, ovarian tumours.
Diagnosis
- Individuals with a personal or family cancer history, smoking history, should be worked up for paraneoplastic involvement.
- The most common tumours associated with paraneoplastic limbic encephalopathy are small cell lung cancer (SCLC) (about 75% of cases), germ-cell tumours (ovarian or testicular), thymoma, Hodgkin's lymphoma, and breast cancer.
- The most common symptoms are a subacute cognitive (primarily amnestic) syndrome.
- Depression, anxiety, personality changes, and emotional lability can often precede the cognitive impairment.
Investigations
- CSF evidence of inflammation
- Elevated tumor markers (e.g. - CEA, CA-125, PSA)