Epilepsy and Limbic Encephalitis (LE)

17th May 2021

Limbic Encephalitis (LE) is a very rare disease that’s often a cause of seizures and epilepsy. Most commonly affecting adults, but LE can affect approximately 1 in 150,000 to 300,000 children in the UK each year. It’s an auto-immune condition whereby the body’s own antibodies begin to attack parts of the body, in the case of LE, this is the brain. 

The limbic system, from which the disease derives its name, is a network of the brain that includes the temporal lobes, the hypothalamus, the frontal lobes and the basal ganglia. Although a cause for LE is unknown, common triggers include viral infections and other auto-immune disease. 

Symptoms 

This particular syndrome has a number of symptoms, including seizures, behavioural difficulties and short-term memory issues. Movement and psychological disorders can also occur with this syndrome. LE can occur very rapidly at the beginning over the course of just a few days. However, in some cases it can develop much more slowly. 

Seizures with LE are usually very frequent in nature and often occur multiple times every day. The seizures can be generalised or focal, and sometimes both. Myoclonic, tonic-clonic and clonic seizures are all common. 

Click here for more information on the various seizure types. 

Diagnosis

A careful history is often required for a diagnosis. Witnessed accounts from family members will be crucial for descriptions of the seizures, when they began and how they present. 

LE is often referred to as a ‘diagnosis by exclusion’, which means it’s often necessary to rule out more common diseases and conditions before LE can be confirmed. For this reason, a vast number of tests may be required to confirm a diagnosis. If these tests come back negative for more common conditions then the diagnosis becomes more likely. Hypocalcemia, hypoglycemia, herpes simplex encephalitis, bacterial meningitis and brain tumours are some examples of conditions that need to be ruled out first.

Blood tests, electroencephalogram (EEG) and magnetic resonance imaging (MRI) tests will all likely show abnormalities that help to diagnose LE, however, this is not always the case. 

Treatment 

Anti-seizure medications can be used to try and control the seizures, although with LE it’s unlikely they will be able to control them completely and at best can reduce the frequency of seizures. 

Finding the cause of the LE is the most important part of the treatment. If it’s a tumour, for example, removing this could be the most effective way to reduce the number of seizures. If it’s a viral infection, such as herpes simplex encephalitis, then a medication can be used to treat the viral infection. 

Immunotherapy medications will often be required, the most common of which are corticosteroids, such as Prednisolone, which can be administered intravenously or orally. Cyclophosphamide or Rituximab are alternative immunotherapy medications. 

Prognosis

The earlier a diagnosis is made of LE, the better the prognosis often is. All symptoms, including seizures, usually respond well to immunotherapy medications, and in many cases can help to stop seizures altogether and also help to minimise the impact of the behavioural issues or short-term memory loss. 

If a late diagnosis is made, the prognosis is not as positive, this is because the auto-antibodies can cause lasting damage (known as ‘scarring’) to one or both of the temporal lobes and other parts of the limbic system. 

National Epilepsy Training can help

For more information on Epilepsy and Limbic Encephalitis (LE), please call us on 01706 373075 or email admin@nationalepilepsytraining.co.uk