Lyme disease, caused by the bacterium Borrelia burgdorferi, is a multisystem illness transmitted by the bite of an infected tick. While this infection primarily affects the skin, joints, and heart, it can also involve the nervous system. Although Lyme disease is not a common cause of chronic epilepsy, it is a recognized infectious trigger for acute symptomatic seizures. Epilepsy is a neurological disorder characterized by recurrent, unprovoked seizures, which are temporary disturbances in the brain’s electrical activity.
How Lyme Disease Affects the Central Nervous System
The foundational mechanism linking Lyme disease to neurological symptoms is neuroborreliosis, which occurs when the Borrelia spirochetes invade the central nervous system (CNS). The bacteria, having entered the bloodstream, must cross the protective blood-brain barrier to gain access to the brain and spinal cord tissues. This invasion typically happens during the disseminated stage of infection, weeks to months after the initial tick bite.
Once in the CNS, the spirochetes trigger a localized inflammatory response, which is the direct cause of neurological damage. This inflammation can manifest as meningitis (inflammation of the membranes surrounding the brain) or encephalitis (inflammation of the brain tissue). The resulting swelling and immune activity disrupt normal neural signaling, creating an irritable environment that lowers the seizure threshold. The physical damage can also involve inflammation of the blood vessels, known as cerebral vasculitis. These focal lesions, combined with general inflammation, cause abnormal electrical discharges that precede a seizure event.
Evaluating the Causal Link to Seizures and Epilepsy
Medical literature confirms that seizures are a possible presentation of neuroborreliosis, often occurring early in the course of the infection. These events are classified as acute symptomatic seizures, meaning they are a direct consequence of the active infection and associated inflammation. Case reports highlight that seizures, such as generalized tonic-clonic episodes, can be the initial recognized symptom of neuroborreliosis.
The distinction between an acute seizure and chronic epilepsy is important in the context of Lyme disease. An acute seizure is a temporary event occurring during intense brain irritation, such as active meningitis or encephalitis. Epilepsy, conversely, involves a long-term predisposition to recurrent, unprovoked seizures after the initial trigger has resolved.
Lyme disease is considered a rare, acquired cause of epilepsy, meaning it can leave behind permanent changes in brain tissue that lead to a chronic seizure disorder. However, the majority of neurologic manifestations of Lyme are limited to cranial nerve palsies, meningitis, and radiculoneuropathy. Seizures attributed to active Lyme disease often resolve completely following appropriate antibiotic treatment, suggesting they were symptomatic of the active infection rather than the onset of chronic epilepsy.
Diagnostic Hurdles in Attributing Epilepsy to Lyme
Confirming Lyme disease as the definitive cause of a seizure disorder presents challenges. Seizures are a non-specific symptom that can be caused by numerous conditions, including head trauma, stroke, genetic factors, or other infections, necessitating a thorough differential diagnosis. Because of the low prevalence, major medical guidelines often recommend against routine Lyme disease testing for patients presenting only with new-onset seizures.
A diagnosis of neuroborreliosis requires more than just a positive blood test for Lyme antibodies. The standard for confirming CNS involvement is a spinal tap, or lumbar puncture, to analyze the cerebrospinal fluid (CSF). Clinicians look for signs of inflammation in the CSF, such as an elevated white blood cell count (pleocytosis) and increased protein levels.
The definitive confirmation of neuroborreliosis relies on finding Borrelia-specific intrathecal antibody synthesis, which indicates that the immune system is producing antibodies against the bacteria directly within the CNS. Interpreting Lyme serology is also complicated by the standard two-step testing process and the potential for false positive results due to cross-reactivity with other conditions.
Treatment Strategies for Lyme Associated Seizures
When a seizure disorder is linked to active neuroborreliosis, the treatment approach is two-fold: targeting the underlying infection and managing the seizure activity. The primary step is administering an appropriate course of antibiotics to eliminate the Borrelia burgdorferi spirochete.
For CNS involvement, intravenous (IV) antibiotics are typically favored to ensure sufficient drug concentration crosses the blood-brain barrier. Common regimens include 14 to 21 days of IV ceftriaxone, cefotaxime, or penicillin G. The goal is to rapidly control the infection and reduce the inflammation that is irritating the brain.
In parallel, standard anti-epileptic drugs (AEDs) are used temporarily to prevent further seizures and stabilize the patient. Successful treatment of the neuroborreliosis is often the key to resolving the seizure activity, allowing physicians to gradually reduce or discontinue the anti-epileptic medication over time.