Death of brain neurons and glial cells came from extracellular acidosis. Research found it  may be a function of both the amount and rapidity of acidification intracellularly.

J Cereb Blood Flow Metab. 1989 Aug;9(4):471-7.The effects of extracellular acidosis on neurons and glia in vitro.Goldman SA, Pulsinelli WA, Clarke WY, Kraig RP, Plum F.Department of Neurology, Cornell University Medical College, New York 10021.