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Disease Profile

Limbic encephalitis

Prevalence
Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

Unknown

Age of onset

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ICD-10

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Inheritance

Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease

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Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype

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X-linked
dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.

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X-linked
recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder

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Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.

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Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.

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Not applicable

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Summary

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]

Symptoms

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]

Cause

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]

Diagnosis

Diagnosis of limbic encephalitis can be made when all three of the following criteria have been met:[14588]

1. Subacute onset (rapid progression of less than 3 months) of working memory deficits (short-term memory loss), altered mental status, or psychiatric symptoms

2. At least one of the following:

• New focal CNS findings
Seizures not explained by a previously known seizure disorder
• CSF pleocytosis (white blood cell count of more than five cells per mm3)
MRI features suggestive of encephalitis

3. Reasonable exclusion of alternative causes

Examples of conditions that must be ruled out before a diagnosis of limbic encephalitis can be made, include:[5]

A team of leading autoimmune encephalitis researchers have established diagnostic criteria for limbic encephalitis. View the full position paper, entitled A Clinical Approach to Diagnosis of Autoimmune Encephalitis.

For more on diagnosis, visit the following link to the International Autoimmune Encephalitis Society Web site:
https://autoimmune-encephalitis.org/diagnosis

Treatment

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.[6][2] If immunotherapy fails, medications such as rituximab or cyclophosphamide may be considered.[2]

Organizations

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

    Social Networking Websites

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

        In-Depth Information

        • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Limbic encephalitis. Click on the link to view a sample search on this topic.

          Selected Full-Text Journal Articles

            References

            1. Anderson NE, Barber PA. Limbic encephalitis a review. Journal of Clinical Neuroscience. 2008; https://www.ncbi.nlm.nih.gov/pubmed/18411052.
            2. Asztely F, Kumlien E.. The diagnosis and treatment of limbic encephalitis. Acta Neurol Scand. Dec 2012; 126(6):365-375. https://www.ncbi.nlm.nih.gov/pubmed/22713136.
            3. Dr Sarosh R Irani, Dr Camilla Buckley and Prof Angela Vincent. Limbic Encephalitis. The Encephalitis Society. August 2013; https://www.encephalitis.info/files/9413/3995/5695/FS013V1.pdf.
            4. Voltz R. Neuropsychological symptoms in paraneoplastic disorders. J Neurol. (2007); https://www.ncbi.nlm.nih.gov/pubmed/17503138.
            5. F Graus, J Delattre, J Antoine, J Dalmau, B Giometto, W Grisold, J Honnorat, P Smitt, C. Vedeler, J Verschuuren, A Vincent, R Voltz. Recommended diagnostic criteria for paraneoplastic neurological syndromes. J Neurol Neurosurg Psychiatry. August 2004; 75(8):1135-1140. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1739186/. Accessed 5/12/2016.
            6. Tuzun E, Dalmau J. Limbic Encephalitis and Variants: Classification, Diagnosis, and Treatment. The Neurologist. 2007;

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