Astrocytes in the affected and non-affected cortices are injured. (a-b) Astrocyte swellings are immunoreactive for (a) AQP4 (AQP4, scale bar = 50 μm)) and (b) AQP1 (AQP1, scale bar = 33 μm). (c) Degenerated astrocyte processes are immunoreactive for GFAP (GFAP, scale bar = 33 μm). (d) Meningeal haemorrhages and inflammation extend into the perivascular spaces and upper cortical layers (HE, scale bar = 200 μm); inset shows neutrophils infiltrating into the molecular layer of the cortex (HE, scale bar = 8.75 μm). (e) Cortical myelin is preserved in regions affected by haemorrhage (PLP, scale bar = 100 μm). (f-g) Astrocytes in the frontal cortex which does not show haemorrhages or vascular changes have (f) swollen processes (AQP4, scale bar = 33 μm) and (g) swollen perivascular end-feet (AQP4, scale bar = 50 μm). (h) Astrocyte swellings in the frontal cortex also display GFAP immunoreactive swellings (GFAP, scale bar = 33 μm). (i-k) Normal morphology of astrocytes in the occipital cortex of this case: (i) parenchymal astrocytes (AQP4, scale bar = 33 μm); (j) perivascular astrocytes (AQP4, scale bar = 50 μm); and (k) astrocytic fibers (GFAP, scale bar = 33 μm).