Narcolepsy with coexisting type 1 diabetes: a case report

Abstract

Narcolepsy is strongly associated with HLA-DQB1∗06:02 which is protective for type 1 diabetes. The combination of these two diseases is extremely rare. Sodium oxybate (SXB) is an efficient treatment of narcolepsy. In a 24 year old Caucasian woman with suspected narcolepsy SXB increased hyperglycemia and ketosis. We report a case of a 15 year old Finnish boy with type 1 diabetes who developed narcolepsy and cataplexy after Pandemrix vaccination (PDRX). At age 12 the boy received PDRX and he developed excessive daytime sleepiness (EDS) 1 month later. Ambiguous cataplexy (CPL), sleep paralysis and hypnagogic hallucinations started 5 months after EDS and disturbed sleep 1 month after the vaccination. The TST was 400 min, sleep efficiency 82%, SL 3 min and REM latency 56 min. AHI was 0.3. MSLT SL was 0.75 min with 4/5 SOREM periods. He is HLA-DQA1∗03:01, 01:02 and DQB1∗03:02, 06:02. EDS was treated with modafinil, and CPL with clomipramine and later with venlafaxine 75 mg. SBX was started at age 15 because of disturbed night sleep and insufficient control of CPL. His diabetes was treated with a sensor-augmented insulin pump. SBX treatment started with 4 g (1.5 g × 2). Tissue glucose was followed continuously with the pump. No significant increase in glucose has been observed and SBX has been well tolerated. Presently he is treated with SBX 7.5 g, modafinil 200–300 mg and venlafaxine 75 mg. The BMI has decreased from 22.4 to 20.7 kg/m2, PDSS score from 20 to 12 and UNS from 15 to 5. WHO5 quality of life score has increased from 45% to 85%. HbA1c has decreased from 64 mmol/mol (8.0%) to 57 mmol/mol (7.4%) during treatment with SBX. A combination of narcolepsy (Brighton level 2) and type 1 diabetes is rare. Contrary to a previous case report SBX ameliorated glucose balance in addition to ameliorating narcolepsy. This study was supported by Academy of Finland (NARPANord, 260603). We thank study nurses of our sleep clinic and the courageous boy and his parents for collaboration.