All are features of the hemolytic uremic syndrome, except -

Hyperkalemia is seen in hemolytic uremic syndrome as a result of renal failure.  ABOUT NEUROPSYCHIATRIC MANIFESTATIONS Neurological manifestations are used to distinguish between the Hemolytic uremic syndrome and Thrombotic Thrombocytopenic Purpura. H.U.S. is distinguished from T.T.P by the absence of neurological symptoms and the prominence of acute renal failure. Recent studies, however, have tended to blur these clinical distinctions. Many adult patients with "TTP" lack one or more of the five criteria and patients with "HUS" have fewer  neurological dysfunction.