How do I work up and manage a cat presenting with new-onset seizures?

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New-onset seizures in a cat require simultaneous stabilization, identification of the underlying cause, and initiation of antiseizure therapy — the diagnostic category (idiopathic epilepsy, structural epilepsy, or reactive seizures) determines both treatment selection and long-term prognosis. --- Seizures affect approximately 1–3% of the general cat population, making them one of the most common neurologic presentations in small animal medicine.6 The first clinical decision is whether the cat is in an active seizure emergency — status epilepticus or cluster seizures — which requires immediate intervention before any diagnostic workup proceeds.7 --- Stabilization of Seizure Emergencies Cats presenting in status epilepticus or with cluster seizures require a stage-based, early, and rapid antiseizure intervention. The 2024 ACVIM Consensus Statement establishes that benzodiazepines are the first-line agents for acute seizure management in cats, with the specific route and agent selected based on clinical stage.7 Midazolam administered intranasally at 0.5 mg/kg (from a 5 mg/mL solution) is an established at-home rescue option for owners managing generalized seizures.2 Successful emergency management requires concurrent treatment of underlying causes and complications alongside antiseizure medications.7 --- Diagnostic Workup The minimum database for any cat with new-onset seizures includes a complete blood count, serum biochemistry panel, thoracic radiographs, brain MRI, and cerebrospinal fluid analysis as indicated by clinical findings.4 Thoracic radiographs are warranted even in the absence of respiratory signs — a cat presenting solely for seizures was found to have primary pulmonary lymphoma identified only on thoracic screening radiographs, with entirely normal auscultation findings.1 MRI is the preferred neuroimaging modality over CT for intracranial evaluation. Computed tomography is less effective than MRI for detecting central nervous system lesions due to inhere