Possible correlation between status epilepticus and hyperglycaemic hyperosmolar syndrome in a West Highland white terrier

Abstract

Status epilepticus secondary to hyperglycaemic hyperosmolar syndrome is a recognised complication of diabetes mellitus in human medicine; however, very few cases have been documented in veterinary medicine. This case report describes the diagnosis and treatment of not previously reported epileptic seizures in a dog shortly after adjustment of insulin therapy for diabetes mellitus. At presentation, the patient was in status epilepticus, and the blood analysis revealed severe hyperglycaemia with absent ketonaemia. With a history of poorly controlled diabetes mellitus, hyperglycaemia was a common finding at previous rechecks when no neurological signs were reported. A targeted anti‐seizure protocol was initiated in an attempt to control the status epilepticus. A multimodal approach with multiple anti‐seizure medications, as per the recommendations in the consensus statement for management of status epilepticus in dogs, was unsuccessful in abiding epileptic seizures. In order to investigate a suspected intracranial disease, a magnetic resonance imaging of the head under general anaesthesia was performed. The study revealed diffuse cortical atrophy, which was deemed unlikely to be the cause of status epilepticus in a 12‐year‐old West Highland white terrier that never showed any other neurological abnormality. Based on these findings, reactive epilepsy was suspected, possibly related to a systemic condition such as a metabolic disease. As a consequence, re‐evaluation of the case was performed, with calculation of serum osmolality. Increased total and effective osmolality were confirmed, raising suspicion of hyperglycaemic hyperosmolar syndrome. Treatment with fluid therapy and neutral insulin continuous‐rate infusion led to improvement of the hyperglycaemia and osmolality. Once the insulin was commenced together with the anti‐seizure medications, the epileptic seizures resolved. Potential mechanisms of onset of epileptic seizures secondary to hyperglycaemic hyperosmolar syndrome and its management are discussed.