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Inflammatory Cerebral amyloid angiopathy (iCAA) is a rare subtype of Cerebral amyloid angiopathy (CAA) with inflammation against vascular amyloid -beta (Aβ) deposits in leptomeningeal and cortical arteries.

A 54-year-old male with history of traumatic subarachnoid hemorrhage, CKD stage III, hyperlipidemia and polysubstance abuse presented with elevated blood pressure, dizziness and altered mental status.

On arrival, patient was hypertensive. Neurological examination revealed right homonymous hemianopsia and right gaze preference. CT head showed stable small right frontoparietal hyper-density and a new low-density area in the left parietal lobe. CTA head and neck was unremarkable. Urine drug screen was positive for cocaine.  Patient was started on nicardipine drip for blood pressure control. MRI brain showed focal area of late subacute hemorrhage, numerous old microhemorrhages, areas of restricted diffusion in the left temporal lobe, left occipital lobe and left parietal lobe. There was associated hyperintensity on the FLAIR sequence within sulci over these regions. Patient received levetiracetam for new onset seizures. Continuous EEG showed periodic lateralized epileptiform discharges in left hemisphere. CSF fluid analysis showed significantly elevated total TAU levels of 861 pg/ml (reference range <=238 pg/mL) and elevated p-tau/Aβ42 ratio concerning iCAA. Patient was treated with intravenous methylprednisolone 1gm for 5 days and discharged on extended oral prednisone taper.  

iCAA is rare and under-recognized clinical syndrome with varied presentation, including subacute cognitive decline, headaches, seizures. Its diagnosis can be challenging due to overlapping features with conditions such as Posterior Reversible Encephalopathy Syndrome or CNS vasculitis. However, key distinguishing factors, like presence of multiple microhemorrhages on SWI MRI sequences and CSF findings showing an elevated p-tau/AB42 ratio, aid in differentiating iCAA from its mimickers. Current treatments primarily involve immunomodulatory therapies, though the optimal approach remains uncertain. Early recognition and prompt treatment of iCAA are critical to reducing therapeutic delays and improving patient outcomes.