Psychiatric Manifestations of Paraneoplastic Disorders

Primer

Paraneoplastic disorders can lead to severe psychiatric and behavioural symptoms. Rapid identification is required to ensure correct treatment and management to avoid misdiagnosis of a paraneoplastic neurologic disorder.

Paraneoplastic Limbic Encephalitis

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] It is usually associated with small cell lung cancer. 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]

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)

Literature

References

1) Shen, K., Xu, Y., Guan, H., Zhong, W., Chen, M., Zhao, J., ... & Wang, M. (2018). Paraneoplastic limbic encephalitis associated with lung cancer. Scientific reports, 8(1), 1-8.
2) Kacem, M., Belloumi, N., Bachouche, I., Mersni, M., Chermiti Ben Abdallah, F., & Fenniche, S. (2018). Paraneoplastic limbic encephalitis revealing a small cell carcinoma of the lung. Respiratory medicine case reports, 26, 157–160.