Early Fever May Not Seal Fate in Status Epilepticus, Landmark French Registry Finds

When a patient is rushed to an intensive care unit in the grip of convulsive status epilepticus—a relentless seizure that refuses to stop—clinicians monitor a long list of numbers on the bedside screen, and body temperature is one of the most anxiously watched. Fever has long been treated as a secondary brain insult, a physiological menace that can amplify damage after stroke, hemorrhage, and cardiac arrest. A new analysis from the large French ICTAL Registry, published in the journal Neurocritical Care, now challenges the assumption that early fever carries the same ominous weight in status epilepticus, suggesting instead that a rising temperature in the first hours may be less a verdict on the brain’s future and more a mirror of the seizure storm itself.

The study, led by Alexis Carriere and Stephane Legriel of the Centre Hospitalier de Versailles together with a broad network of French intensivists, set out to answer a deceptively simple question: does fever developing within the first 24 hours after the onset of convulsive status epilepticus independently worsen neurological recovery? To find out, the researchers turned to the ICTAL Registry, a prospective, multicenter observational database that has become one of the richest sources of real-world evidence on this devastating neurological emergency. Their analysis encompassed 952 adults admitted to 23 French intensive care units, making it one of the largest efforts to date to disentangle the prognostic meaning of hyperthermia in this population.

The technical definition matters here. Fever was defined as a core temperature of at least 38 degrees Celsius, measured during the first 24 hours following seizure onset. The outcome of interest was equally concrete: a favorable neurological outcome at 90 days, operationalized as a score of 4 or 5 on the Glasgow Outcome Scale, which ranges from death and persistent vegetative states at the bottom to good recovery and moderate disability with independence at the top. This 90-day functional endpoint is widely regarded as the gold standard in neurocritical care trials because it captures what actually matters to patients and families—whether a person can think, move, and live independently after a catastrophic brain event.

What the team found was striking in its prevalence. Of the 952 patients, 382—41.2 percent—developed fever within the first 24 hours of their intensive care stay. That figure alone underscores how common this physiological disturbance is in the immediate aftermath of prolonged convulsive seizures. But the origins of that fever proved to be decidedly multifactorial. Some patients had infectious causes directly related to the status epilepticus itself, including systemic infections or infections of the central nervous system such as encephalitis or meningitis. Others developed early aspiration pneumonia, a well-known complication when consciousness is lost and airway protective reflexes fail. And a third contributor emerged that is less obvious to outsiders: the sheer intensity of the convulsive activity, which generates massive heat and triggers inflammatory cascades throughout the body.

To isolate which of these factors truly drove fever, the investigators employed sophisticated statistical machinery, including multivariable logistic regression and matching techniques designed to balance the fever and non-fever groups on measurable characteristics. After matching, a revealing pattern emerged: only the intensity of convulsive activity remained associated with the occurrence of fever. In other words, the harder and longer the brain seized, the more likely the body was to run hot. The infectious contributors, while clinically important in their own right, did not stand out as independent drivers of early fever once the analysis accounted for other variables—a finding that reframes early hyperthermia in status epilepticus as a signal of seizure severity rather than a standalone disease process.

The prognostic verdict, however, was the study’s headline result. In multivariable analyses adjusting for the full panel of potential confounders, early fever was not independently associated with 90-day functional outcome. Instead, the familiar determinants of recovery reasserted themselves. Patients younger than 60 years and those with a Charlson Comorbidity Index below 3—indicating a lighter burden of chronic illness—had significantly better odds of favorable neurological outcome. Conversely, two factors predicted poor recovery: when the underlying cause of the status epilepticus was a cerebral insult, such as a stroke or other structural brain injury, and when the episode proved refractory, meaning seizures persisted despite adequate doses of first- and second-line anticonvulsant drugs. These predictors align with decades of literature on status epilepticus outcomes, reinforcing that etiology, age, comorbidity, and treatment resistance remain the pillars of prognosis.

The biological backdrop to this question is worth unpacking. In many acute brain injuries, fever is genuinely harmful: elevated brain temperature accelerates excitotoxic neurotransmitter release, worsens metabolic supply-demand mismatch, promotes blood-brain barrier breakdown, and amplifies inflammatory signaling. Consensus guidelines for intracerebral hemorrhage, subarachnoid hemorrhage, and ischemic stroke accordingly recommend aggressive temperature control. Experimental work in epilepsy has also shown that inflammatory mediators such as cytokines can lower seizure thresholds and perpetuate epileptic activity, creating a plausible loop in which fever and seizures feed each other. It was precisely this mechanistic plausibility that made the ICTAL findings surprising—and important. If fever in status epilepticus were an independent toxin, one would expect it to survive statistical adjustment. It did not.

The authors are careful, appropriately, not to overclaim. Their conclusions note that early fever is highly prevalent and appears to reflect seizure intensity rather than overall disease severity, that it showed no independent association with 90-day neurological outcome, and that no major prognostic impact is suggested—although they explicitly acknowledge that a modest association cannot be excluded. This caution is scientifically warranted. An observational registry, however large and well-adjusted, cannot fully eliminate confounding by indication: patients who seize violently enough to become febrile are also patients whose illness is intrinsically more severe, and no statistical model can perfectly separate the heat from the fire. The researchers also stress that their findings do not permit conclusions about whether actively cooling patients—targeted temperature management—would help or harm in status epilepticus. That question was tested in a previous randomized trial by the same group, published in the New England Journal of Medicine in 2016, which found that induced hypothermia did not improve outcomes in convulsive status epilepticus, and the current results neither revive nor bury the idea of temperature intervention.

For clinicians at the bedside, the practical message is nuanced but actionable. A fever in the first day of status epilepticus should still trigger a diligent hunt for its cause—blood cultures, chest imaging, lumbar puncture when infection of the central nervous system is suspected—because treatable infections matter regardless of whether the fever itself is prognostically neutral. Aspiration pneumonia, in particular, demands vigilance and early antibiotic therapy. But the new evidence suggests that the number on the thermometer, in isolation, should not be read as a sentence on the patient’s future. The stronger prognostic signals remain the ones clinicians already know: the patient’s age, their chronic health burden, the cause of the seizures, and whether the seizures yield to treatment.

For the field of neurocritical care, the study exemplifies the value of large, prospective, disease-specific registries. The ICTAL Registry, registered with ClinicalTrials.gov and coordinated through the IctalGroup Research Network based at Versailles, has previously yielded insights ranging from early electrocardiographic changes in status epilepticus to health-related quality of life in survivors. By demonstrating that one of the most feared secondary brain insults may be a marker rather than a mechanism of poor outcome in this specific condition, the current analysis sharpens the research agenda: future work should focus on modulating seizure intensity itself and on rigorously testing temperature-control strategies in properly designed trials, rather than assuming that fever behaves identically across all forms of acute brain injury. In medicine, as this study elegantly shows, even the most intuitive assumptions deserve to be tested against data.

Subject of Research: The prognostic significance of early fever in adult convulsive status epilepticus

Article Title: Prognostic Significance of Early Fever in Convulsive Status Epilepticus: Insights from the ICTAL Registry

Article References: Carriere, A., Chelly, J., Quenot, J.-P., Lascarrou, J.-B., Bernard, C., Lesieur, O., Monchi, M., Beuret, P., Sigaud, F., Sboui, G., Bailly, P., Chambon, R., Fontaine, C., Mongardon, N., Cerf, C., Bruel, C., Pichon, N., Argaud, L., Desmeulles, I., … Legriel, S. (2026). Prognostic Significance of Early Fever in Convulsive Status Epilepticus: Insights from the ICTAL Registry. Neurocritical Care. https://doi.org/10.1007/s12028-026-02673-2

Image Credits: AI Generated

DOI: 10.1007/s12028-026-02673-2

Keywords: status epilepticus, fever, hyperthermia, ICTAL Registry, neurocritical care, intensive care, prognosis, seizures, secondary brain injury, Glasgow Outcome Scale, temperature management, epilepsy