Recurrent prolonged motor events with different evidence of disease activity in cerebral amyloid angiopathy-related inflammation: a longitudinal case report

Cerebral amyloid angiopathy-related inflammation (CAA-ri) is a treatable disorder in which seizures may accompany active inflammation. Previous reports have mainly described seizures during active disease or relapse accompanied by new magnetic resonance imaging (MRI) abnormalities. Less is known about how recurrent prolonged motor events should be interpreted when clinical, MRI, and cerebrospinal fluid (CSF) findings do not change in parallel. We describe four admissions in one patient to assess renewed inflammatory activity using longitudinal clinical, MRI, and CSF findings. A 67-year-old woman presented with headache, cognitive decline, bilateral vasogenic edema with left temporoparieto-occipital predominance, lobar microbleeds, and inflammatory cerebrospinal fluid (CSF), fulfilling criteria for probable CAA-ri. Symptoms and MRI and CSF abnormalities improved after corticosteroids. At the third admission, an approximately 30-minute bilateral tonic-clonic seizure met the clinical duration criterion for convulsive status epilepticus and was followed by encephalopathy and severe right hemiparesis, likely reflecting inflammatory lesion burden and possible postictal Todd paresis. Diazepam 10 mg was given intravenously during the convulsions. MRI showed renewed edema and widespread leptomeningeal enhancement; CSF opening pressure exceeded 300 mmH₂O and interleukin-6 was 61.59 pg/mL. Intensified corticosteroids and maintenance valproate were followed by improvement. At the fourth admission, prolonged seizure-like motor events followed recent SARS-CoV-2 infection with serum sodium of 128.2 mmol/L, despite continued prednisone and valproate. MRI and major CSF measures continued to improve. The events were not captured by ictal video-electroencephalography, and their epileptic nature remained uncertain. Microbleed Anatomical Rating Scale (MARS)-based assessment showed a conservative lower bound of ≥100 definite lobar microbleeds at each examination, with stable regional categories but a ceiling effect limiting detection of increases. In this patient, recurrent prolonged motor events occurred with different evidence of CAA-ri activity. New or worsening inflammatory MRI abnormalities were central to identifying renewed activity, whereas serial CSF findings provided supporting context when clinical and imaging findings did not change together. Mild residual CSF abnormalities during radiological improvement should not be interpreted as relapse in isolation. Recurrent motor events should prompt reassessment of imaging, CSF when clinically appropriate, and competing causes rather than automatic escalation of immunosuppression.