I had an antidepressant‑overdose‑induced generalized tonic‑clonic seizure concurrent with a concussion and have been experiencing complex partial seizures for six years; both routine electroencephalogram and non‑contrast head computed tomography are normal—does this still allow a diagnosis of post‑traumatic epilepsy?

Post-Traumatic Epilepsy Can Be Diagnosed Despite Normal EEG and CT

Yes, post-traumatic epilepsy remains a valid diagnosis even when both routine EEG and non-contrast head CT are normal—this occurs in approximately 53% of patients with early post-traumatic seizures after mild closed head injury. 1

Why Normal Studies Don't Exclude the Diagnosis

CT Limitations in Post-Traumatic Epilepsy

• CT has poor sensitivity for epileptogenic lesions, detecting abnormalities in only 30% of cases compared to MRI's superior detection rate 2
• In patients with early post-traumatic seizures after mild closed head injury, 53% have completely normal CT findings despite clinically evident seizures 1
• CT particularly misses lesions in orbitofrontal and medial temporal regions where epileptogenic foci commonly develop 2
• Even when CT appears normal, MRI subsequently reveals abnormalities in 29% of patients with focal seizure features 3

EEG Limitations in Epilepsy Diagnosis

• Routine EEG captures only a brief snapshot and frequently misses interictal epileptiform discharges, especially in focal epilepsies 4
• The absence of epileptiform abnormalities on routine EEG does not exclude epilepsy—clinical seizure history remains the cornerstone of diagnosis 5
• Epileptiform abnormalities detected acutely after traumatic brain injury do increase subsequent epilepsy risk, but their absence doesn't rule it out 4

Your Clinical Picture Strongly Supports Post-Traumatic Epilepsy

Key Diagnostic Features Present

• You experienced a documented generalized tonic-clonic seizure concurrent with head trauma—this establishes the traumatic brain injury as the precipitating event 6, 7
• Six years of complex partial seizures (focal seizures with impaired awareness) following the initial injury fits the natural history of post-traumatic epilepsy, which can appear years after head injury 5
• Focal seizures have recurrence rates up to 94%, considerably higher than generalized seizures at 72%, consistent with your ongoing symptoms 3

The Pathophysiology Explains Normal Imaging

• Post-traumatic epilepsy develops through epileptogenic changes at the microscopic level—gliosis, altered neuronal networks, and cortical reorganization—that may not be visible on routine imaging 7, 5
• Diffuse axonal injury, a major risk factor for post-traumatic seizures, is typically not apparent on CT and requires specialized MRI sequences (susceptibility-weighted imaging, diffusion-weighted imaging) to detect 6, 7
• The mechanism by which brain trauma leads to recurrent seizures involves cortical lesions at a cellular level that standard imaging cannot resolve 5

What You Should Do Next

Obtain Proper Imaging

• MRI with a dedicated epilepsy protocol is essential and should have been performed long ago 2, 3
• The protocol must include: coronal T1-weighted imaging (3mm) perpendicular to the hippocampus, high-resolution 3D T1-weighted gradient echo with 1mm isotropic voxels, coronal T2-weighted sequences, and coronal/axial FLAIR sequences 2
• Request 3T MRI over 1.5T when available for improved lesion detection 2
• MRI is particularly useful for identifying gliosis and volume loss from prior traumatic brain injury that CT cannot detect 6, 7

Consider Advanced EEG Monitoring

• Prolonged video-EEG monitoring may capture ictal or interictal epileptiform discharges that routine EEG misses 4
• This is especially important given your focal seizures with impaired awareness, which show ictal discharges originating from one hemisphere 3

Critical Pitfall to Avoid

The most dangerous error is assuming normal CT and routine EEG exclude structural epileptogenic pathology—this false reassurance delays appropriate MRI evaluation and potentially curative surgical options if a focal lesion is identified 2, 3. Your six-year history of ongoing complex partial seizures following documented head trauma with initial generalized seizure constitutes post-traumatic epilepsy by definition, regardless of negative routine studies 5.