Insulinoma Treated As Epilepsy; a Case of Misdiagnosis

A49 year old female with learning disability and 2 years history of epilepsy was admitted following a siezure like activity and fall during a routine visit to her GP surgery. She had sustained injury to left knee and xray confirmed a distal femur and a patellar fracture. On admission her serum glucose was 2.0 mmol, all other routine blood tests including Full Blood Count, Renal function and Liver function test were normal. Her regular medications included Lamotrigine and Mebeverien. On the ward she had recurrent spontaneous hypoglycaemic episodes requiring regular treatment with glucose infusions. The lowest capillary blood glucose recorded was 1.9 mmol. Due to the learning disability, patient could not describe any symptoms usually experienced at the onset of hypoglycaemia. Glycated Haemoglobin (HbA1c) was 19.0 mmol (Ref range: 2041 mmol) indicating lower than normal average glucose. Random cortisol and thyroid function test were normal. She underwent left knee exploration and repair of medial retinaculum of quadriceps tendon and excision of patellar fragment. While awaiting results of further investigations, Diazoxide was initiated with good effect. The results of the specific biochemical investigations for her recurrent hypoglycaemia were consistent with endogenous hyperinsulinaemic hypoglycaemia (Table 1).