[2] ARIA-E refers to cerebral edema, involving the breakdown of the tight endothelial junctions of the blood-brain barrier and subsequent accumulation of fluid.

Symptoms may include headache, changes in mental state, confusion, vomiting, nausea, tremor and gait disturbances.

[4] ARIA-H refers to cerebral microhaemorrhages (mH), small haemorrhages on the brain,[5] often accompanied by hemosiderosis.

Firstly, in the context of aging and neurodegeneration, the integrity of the blood-brain barrier (BBB) can become compromised, resulting in increased permeability.

[7] However, upon the administration of antibodies, these plaques are targeted and subsequently eliminated, potentially uncovering the occurrence of micro-hemorrhage [8][9] Secondly, an alternate perspective posits that the introduction of antibodies into the bloodstream triggers an immune-inflammatory response as part of the treatment regimen.