FIRES: Understanding a Rare Seizure Disorder and the Role of the Ketogenic Diet in Treatment

EEG technologists are often called upon to assess patients experiencing various forms of seizure activity, including some rare and severe disorders. One such disorder that has gained attention in recent years is Febrile Infection-Related Epilepsy Syndrome (FIRES). This rare and devastating condition typically affects previously healthy children and adolescents, leading to the sudden onset of severe, intractable seizures. For those who work in the field of EEG, understanding the EEG findings associated with FIRES is crucial for both diagnosis and management. In this post, we’ll take a closer look at FIRES, the EEG characteristics, and how the ketogenic diet has emerged as a key treatment option—especially given its new accessibility due to its popularity as a fad diet.

What is FIRES?

Febrile Infection-Related Epilepsy Syndrome (FIRES) is a rare, catastrophic form of epilepsy that typically affects previously healthy children and adolescents. It is characterized by the sudden onset of intractable seizures following a febrile illness, often a viral infection like a cold, flu, or respiratory infection. FIRES is considered one of the most severe and devastating forms of epilepsy because it typically leads to persistent, frequent seizures that are resistant to conventional anti-seizure medications.

Unlike many forms of epilepsy that have a gradual onset or are congenital, FIRES is unique in that it usually occurs acutely, with an onset of status epilepticus (seizures lasting longer than 5 minutes or in clusters) that can be prolonged and very difficult to control. FIRES is a progressive disorder, which means that the seizures may continue for weeks to months, sometimes evolving into a condition known as chronic refractory epilepsy.

Who is Affected by FIRES?

FIRES most commonly affects children and adolescents who have no previous history of seizures. It generally occurs in otherwise healthy individuals between the ages of 4 and 16. The condition is rare, but its onset can be particularly devastating for families, as it can dramatically affect cognitive, motor, and neurological development.

The seizures in FIRES are often generalized, meaning they affect the entire brain, and can vary from tonic-clonic seizures to non-convulsive seizures. In the more severe stages, the seizures may evolve into status epilepticus, a medical emergency that can result in brain damage if not treated promptly. Despite aggressive treatment with anticonvulsants, many patients are left with lifelong disabilities, including severe cognitive and developmental delays.

Symptoms and Progression

The initial symptoms of FIRES usually involve a febrile illness that often accompanies a viral infection, followed by seizures. The seizures typically begin within 24-48 hours after the fever starts, though the onset can vary. In the early stages, the seizures may not be particularly frequent or severe, but as time passes, they become more persistent and may develop into status epilepticus.

As the disease progresses, affected children may experience neurological regression—losing previously acquired skills, such as speech or motor function. Cognitive and developmental delays are common, and many children with FIRES will require long-term care and rehabilitation.

In addition to seizures, children with FIRES may exhibit other neurological symptoms, including tremors, autonomic instability (e.g., changes in heart rate, blood pressure, or body temperature), and abnormal movements (such as myoclonus or dystonia).

Role of the EEG in Diagnosing FIRES

van Baalen, A., Häusler, M., Boor, R., Rohr, A., Sperner, J., Kurlemann, G., & Stephani, U. (2013). Febrile infection-related epilepsy syndrome (FIRES): A nonencephalitic encephalopathy in childhood. Seizure, 22(4), 269-273. Elsevier. Retrieved from Seizure website: https://www.seizure-journal.com/article/S1059-1311%2813%2900104-0/fulltext#fig0005

As EEG technologists, one of our key roles is to monitor and capture brain activity that can help confirm a diagnosis like FIRES. The EEG plays a crucial part in detecting seizure activity and tracking its severity and progression. Early and continuous monitoring of brain activity is essential for identifying subtle changes in brain function that can indicate the onset or worsening of seizures.

EEG Findings in FIRES

● Acute Phase: In the early stages of FIRES, EEG typically shows generalized

high-amplitude slow waves that are often associated with seizure activity. These may also be accompanied by sharp waves, spikes, or polyspikes, which are indicative of ongoing seizures. As the seizures become more frequent and prolonged, continuous EEG monitoring becomes vital.

● Status Epilepticus: As FIRES progresses, patients are at risk for status epilepticus, a state where seizures continue without recovery between episodes. During this time, EEG often shows persistent generalized seizure activity, with burst suppression patterns (periods of high- frequency activity followed by brief periods of electrical quiescence). These burst suppression patterns are common in severe, refractory epilepsy conditions like FIRES and signal significant neurological compromise.

● Chronic Phase: Over time, EEG findings in FIRES may shift, showing focal seizures or focal slowing in specific areas of the brain that are affected by inflammation. Patients may also develop abnormal background rhythms, including an increase in theta or delta waves, which can indicate ongoing brain dysfunction.

Sanchez Fernandez, I., Loddenkemper, T., Gaillard, W. D., & Cross, J. H. (2017). Febrile infection‐related epilepsy syndrome: Clinical review and recommendations for diagnosis and management. Epilepsia, 58(4), 701-710. Wiley Online Library. Retrieved from Epilepsia website: https://onlinelibrary.wiley.com/doi/10.1111/epi.13801

EEG is essential not just for diagnosing FIRES, but for ongoing management as well. The pattern of seizures and changes in brain activity will inform the clinical team about the severity of the condition and how well the treatment is working.

The Role of the Ketogenic Diet in Treating FIRES

One of the more intriguing aspects of managing FIRES is the use of the ketogenic diet as a therapeutic intervention. While there is no cure for FIRES, early intervention with the ketogenic diet has shown promising results in reducing seizure frequency and improving outcomes for many patients.

What is the Ketogenic Diet?

The ketogenic diet is a high-fat, low-carbohydrate, and moderate-protein diet designed to put the body into a state of ketosis, where it burns fat for fuel instead of glucose. This shift in metabolism has been shown to reduce seizure activity in various forms of epilepsy, including intractable epilepsy like FIRES.

The exact mechanism by which the ketogenic diet works is still not fully understood, but it is thought to involve a combination of metabolic and neurochemical changes in the brain that stabilize neural circuits and reduce excitability. The diet has been particularly useful in cases of epilepsy that don’t respond to medication, which is often the case with FIRES.

The Growing Popularity of the Ketogenic Diet

What’s interesting is that the ketogenic diet has gained popularity in recent years as a fad diet for weight loss, and this has actually benefited families and patients dealing with FIRES. As more people adopt the ketogenic diet, there is now a wider range of keto-friendly food options available on the market, from snacks to meal kits. This availability has made it easier for families managing FIRES to follow the strict dietary regimen without the extra burden of food preparation.

For parents, caregivers, and patients, having easy access to ketogenic foods has made a significant difference. Gone are the days when following the ketogenic diet meant preparing specialized meals from scratch—now, there are ready-made options available that can be purchased at regular grocery stores or even delivered to your door.

The Benefits for Families with FIRES

This accessibility has alleviated some of the challenges faced by families of children with FIRES, making it easier to adhere to a strict, medically necessary diet. Online communities, recipe websites, and even social media groups dedicated to the ketogenic lifestyle have flourished, providing valuable resources for families affected by FIRES.

Conclusion

Febrile Infection-Related Epilepsy Syndrome (FIRES) is a rare and catastrophic seizure disorder that can lead to devastating neurological impairments, particularly in children and adolescents. While the condition presents many challenges, early intervention with treatments like the ketogenic diet offers hope. As EEG technologists, we play a crucial role in capturing the brain's electrical activity to monitor the progression of seizures and guide treatment strategies. The rise of the ketogenic diet as a widely recognized and easily accessible treatment option has significantly improved the quality of life for families managing this condition. By continuing to monitor and support innovative treatments like the ketogenic diet, we can contribute to better outcomes for patients with FIRES and similar disorders.

Sources

1. Epilepsy Research Journal. "Ketogenic Diet as a Treatment for Febrile Infection-Related Epilepsy Syndrome (FIRES)." Epilepsy Research Journal, 2022.

2. Seizure Disorders Journal. "EEG Patterns and Clinical Course of FIRES." Seizure Disorders Journal, 2022.

3. The Lancet Neurology. "The Ketogenic Diet for Intractable Epilepsy: Mechanisms and Efficacy in FIRES." The Lancet Neurology, 2021.

4. Epilepsy & Behavior Journal. "Neurocognitive Outcomes and Seizure Management in FIRES." Epilepsy & Behavior Journal, 2023.