Serum S‐100β protein is a potential biochemical marker for cerebral oedema complicating severe diabetic ketoacidosis

SUMMARY Case report  A 39‐year‐old man with Type 1 diabetes mellitus was hospitalized with severe diabetic ketoacidosis (DKA). Sixteen hours after admission he suddenly deteriorated having a respiratory then cardiac arrest. A brain computed tomography scan performed 2 h after the respiratory arrest showed severe cerebral oedema. Serial serum samples were stored and analysed for S‐100β protein. The S‐100β protein concentration was initially normal (0.12 μg/l) then rose significantly before the onset of the respiratory arrest (8.5 h = 0.61 μg/l, 14.5 h = 0.9 μg/l, 18 h = 1.6 μg/l, 25.5 h = 3.1 μg/l, 34 h = 4.6 μg/l and 44 h = 19.5 μg/l).Conclusions  In this case of DKA, serum S‐100β concentration rose coinciding with the onset of cerebral oedema, before it became clinically evident. Monitoring serum S‐100β may have a useful role in the management of DKA.Keywords cerebral oedema, diabetic ketoacidosis, S‐100β protein