Seizures that were once well controlled can start breaking through for a surprisingly wide range of reasons, from missed sleep to a simple cold with fever. In one study of patients with breakthrough seizures, 88% could identify at least one clear trigger. That means the increase you’re experiencing likely has an identifiable cause, and in many cases, it’s something that can be addressed.
The Most Common Triggers
Research on breakthrough seizures has identified a consistent hierarchy of triggers. The single most common is a systemic infection with fever, accounting for roughly 53% of cases. This includes ordinary illnesses like upper respiratory infections and chest infections. Fever raises your brain’s overall excitability, which can push past the threshold your medication normally controls.
The second most common trigger is not taking medication consistently, showing up in about 34% of cases. Even small gaps matter. Missing a single dose can cause a dip in your blood drug levels large enough to allow a seizure. If you’ve been inconsistent with timing or accidentally skipped doses, that’s one of the first things to address.
Sleep deprivation ranks third, reported in about 24% of breakthrough cases. Excessive screen time on electronic devices came in fourth at around 20%. Less common triggers included pain, constipation, loud noise, and cold weather, though these were mostly seen in patients with additional neurological conditions like cerebral palsy.
How Sleep Loss Changes Your Brain Chemistry
Sleep deprivation doesn’t just make you tired. It physically shifts the balance of brain chemicals that keep seizures in check. When you lose sleep, your brain ramps up glutamate activity, which is the main chemical signal that excites neurons and makes them fire. At the same time, it dials down GABA, the chemical that normally acts as a brake on that firing. The result is a brain that’s simultaneously more excitable and less able to suppress that excitability. This is why even one night of poor sleep can trigger a seizure in someone who hasn’t had one in months.
Hormonal Shifts in Women
If you menstruate and notice your seizures clustering around your period, hormones are a likely factor. Estrogen tends to increase brain excitability, while progesterone has a calming, protective effect. Throughout your cycle, the ratio between these two hormones fluctuates significantly.
Seizures are most likely during the premenstrual and preovulatory periods, when estrogen is high relative to progesterone. They’re least likely during the mid-luteal phase, when progesterone peaks. Studies have found that women with cycle-linked seizures (called catamenial epilepsy) have lower progesterone levels and a higher estrogen-to-progesterone ratio during the perimenstrual window compared to women whose seizures don’t follow this pattern. If you suspect a connection, tracking both your seizures and your cycle for two to three months can help confirm it and open up targeted treatment options.
Your Medication May Be Less Effective
Even if you take your medication perfectly, your brain can adapt to it over time. This happens through several pathways. Your liver may begin breaking down the drug faster than it used to, a process called metabolic tolerance. Or the receptors in your brain that the drug targets may lose sensitivity, so the same concentration of medication has less effect.
There’s also a newer understanding: your brain’s network of connections can physically reorganize over time. Even if the drug works exactly as it always has at the cellular level, changes in how different brain regions connect and communicate can allow seizures to re-emerge through new pathways. Think of it like water finding a new route around a dam. This is one reason seizure control can erode gradually rather than failing all at once.
Drug Interactions That Lower Your Levels
Other medications can quietly undermine your seizure drugs. Oral contraceptives, for example, can cut blood levels of lamotrigine (a common epilepsy medication) by about 50%. Certain antibiotics can cause a dramatic drop in valproic acid levels. Some chemotherapy drugs lower phenytoin concentrations. If you’ve recently started any new medication, including over-the-counter supplements, it’s worth checking whether it interacts with your seizure treatment.
Metabolic and Blood Sugar Disruptions
Your brain is extraordinarily sensitive to its fuel supply. Low blood sugar (hypoglycemia) is a known seizure trigger because neurons depend on a constant stream of glucose to function properly. There’s even a genetic condition, glucose transporter 1 deficiency, where the brain can’t import enough glucose, and seizures characteristically become more frequent before meals when blood sugar dips.
Electrolyte imbalances, dehydration, and significant changes in diet can also shift your seizure threshold. If you’ve recently changed your eating patterns, started fasting, or been ill with vomiting or diarrhea, the metabolic disruption alone could explain an increase in seizure activity.
When Seizures Resist Multiple Medications
If your seizures have continued despite trying two or more appropriately chosen medications at adequate doses, the International League Against Epilepsy classifies this as drug-resistant epilepsy. This isn’t a rare situation. It affects roughly one in three people with epilepsy. The formal threshold is failure of two medication trials, whether those were single drugs or combinations, to achieve complete seizure freedom for at least 12 months.
Being classified as drug-resistant doesn’t mean nothing else can help. It means the conversation shifts toward additional options. Responsive neurostimulation (a device implanted in the brain that detects and interrupts seizure activity) reduced seizures by about 66% at one year and 68% at three years in clinical data. Vagus nerve stimulation, a less invasive device implanted near the collarbone, showed a 33% reduction at one year that improved to about 54% by year three as the brain adapted to the therapy. Deep brain stimulation fell in between, with reductions around 58% at one year and 64% at three years.
Progressive Conditions
In a small number of cases, increasing seizure frequency is part of a condition’s natural course. Progressive myoclonic epilepsy type 1, for instance, typically begins between ages six and fifteen with infrequent seizures that then increase over the following three to seven years as part of ongoing neurological deterioration. These progressive syndromes are uncommon and are usually identified early in life, but if your seizures are worsening steadily without any identifiable trigger, your neurologist may explore whether an underlying progressive condition is involved.
Keeping a Useful Seizure Log
Seizure type and frequency are considered the vital signs of epilepsy care. Your neurologist needs specific data to adjust your treatment effectively. A useful log captures the date and time of each seizure, what you were doing beforehand, how long the event lasted, what it looked like or felt like, and any potential triggers you can identify (poor sleep, illness, missed medication, stress, menstrual timing). Patterns that seem invisible day to day often become obvious when you look at weeks or months of data together. Several smartphone apps can make this tracking easier and generate reports you can share at appointments.
If your seizures are becoming more frequent, the pattern of when they happen and what surrounds them often points directly to the cause. That information is the single most useful thing you can bring to your next neurology visit.