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Genetic and Rare Diseases Information Center (GARD)

Limbic encephalitis

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Your Question

What is limbic encephalitis?  I am working with a patient with this condition.

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What is limbic encephalitis?

Limbic encephalitis represents a group of autoimmune conditions characterized by inflammation of the limbic system and other parts of the brain. The cardinal sign of limbic encephalitis is a severe impairment of short-term memory; however, symptoms may also include confusion, psychiatric symptoms, and seizures. The symptoms typically develop over a few weeks or months, but they may evolve over a few days. Limbic encephalitis is often associated with an underlying neoplasm (paraneoplastic limbic encephalitis); however some cases never have a neoplasm identified (non-paraneoplastic limbic encephalitis). Delayed diagnosis is common, but improvements are being made to assist in early detection. Various tests including imaging studies (MRI, PET) laboratory tests (CSF analysis), and tests that measure the electrical activity of the brain (EEG) may be utilized to confirm a diagnosis. Treatment includes removal of the neoplasm (if identified) and immunotherapy.[1][2][3]
Last updated: 4/26/2016

What causes limbic encephalitis?

Limbic encephalitis is thought to be caused by a reaction of the immune system to various stimuli such as cancers, tumors, infections, and generalized autoimmune disorders.[3] In many patients, limbic encephalitis is associated with a tumor or cancer. This is known as paraneoplastic limbic encephalitis (PLE). PLE is most commonly associated with small cell lung cancer (SCLC), which is present in 40% of cases. It may additionally be associated with breast cancertesticular cancer, and nearly any other tumor.[4][2] Limbic encephalitis can also occur in the absence of cancer, known as non-paraneoplastic limbic encephalitis (NPLE), such as in the case of a viral infection (for example herpes simplex virus) or systemic autoimmune disorders. In some instances, the cause of limbic encephalitis may never be determined.[2][3]
Last updated: 5/12/2016

What are the signs and symptoms of limbic encephalitis?

Although the symptoms of the condition may vary from person to person, the presenting sign of limbic encephalitis is severe impairment of short-term memory, with most patients having difficulties in recall. Epileptic seizures are common and may occur prior to symptoms of memory loss.[2] A variety of symptoms may be associated with limbic encephalitis such as anterograde amnesia (the inability to store new memories after the onset of the condition), anxiety, depression, irritability, personality change, acute confusional state, hallucinations and seizures.

Other possible symptoms may include obsessiveness, hyperthermia (increase in body temperature), weight change, sleep disturbances, endocrine dysfunction, aphasia, and apraxia.[4][2] The symptoms associated with limbic encephalitis can develop over a few days, weeks, or months. It is important to note the neurological symptoms generally precede diagnosis of the malignancy in 60%-75% of patients that have paraneoplastic limbic encephalitis.[1]
Last updated: 5/11/2016

How might limbic encephalitis be treated?

Treatment for limbic encephalitis varies depending on the underlying cause. In cases of confirmed paraneoplastic limbic encephalitis (PLE), removal or treatment of the tumor is often the first step in treatment. If the cause of limbic encephalitis is a viral infection, an antiviral drug may be prescribed. Immunotherapy is often utilized as a first line or second line treatment.[5][2] If immunotherapy fails, medications such as rituximab or cyclophosphamide may be considered.[2]
Last updated: 5/12/2016

What is the long-term outlook for limbic encephalitis?

The prognosis for limbic encephalitis varies from person to person and is based on the underlying cause of the condition. For example, individuals that have small cell lung carcinoma (SCLC) and test positive for an antibody called anti-Hu, tend to respond poorly to treatment, whereas individuals that have an ovarian teratoma and test positive for the NMDAR antibody respond well to treatment.[1]

Given evidence that paraneoplastic limbic encephalitis may occur prior to identification of a tumor, if a tumor is not initially identified, regular tumor screening may be recommended to occur after treatment is completed.[2]
Last updated: 5/12/2016

See Disclaimer regarding information on this site. Some links on this page may take you to organizations outside of the National Institutes of Health.