Changing the Treatment of Permanent Neonatal Diabetes Mellitus from Insulin to Glibenclamide in a 4-Month-Old Infant with KCNJ11 Activating Mutation
The case was a 2-month-old male infant who had been referred to Namazee Hospital, Shiraz, Iran 7 days before the admission due to poor feeding, restlessness, and tachypnea. He was born through the cesarean section by a 31-year-old mother with the gestational age of 35 weeks, birth weight of 2450 g, and good APGAR (Appearance, Grimace, Activity, Respiration)1. The mother had undergone the cesarean section because of hypertension. The parents had non-consanguineous marriage and no history of specific diseases such as diabetes was there in the family.\nThe patient was hospitalized in Neonatal Intensive Care Unit(NICU)1 for 5 days with diagnosis of respiratory distress syndrome and then discharged with good general condition. He had desirable health status up to 1 week prior to admission. Then, he presented with poor feeding, restlessness, and respiratory distress and was referred to the hospital.\nIn the physical examination, the patient seemed dehydrated and lethargic and had kussmaul-respiration. Weight, length, and head circumference of the patient were 4200 g, 50 cm, and 37 cm, respectively and the rest of the physical examinations were normal. Moreover, the patient's laboratory findings revealed BS (Blood Sugar)2=410 mg/dl, BUN (Blood Urea Nitrogen)1=25 mg/dl, Na = 140 mEq/l, K = 3.9 mEq/l, pH = 7.12, HCO3= 8, PCO2= 21, and severe ketonemia.\nThe patient's treatment was started with intravenous fluid followed by insulin. During the hospital stay, he had two episodes of convulsion. After recovery from the acute phase of the disease, since the patient had permanent hyperglycemia, NPH3 insulin was started for him and finally he was discharged with 2.5 units NPH (Neutral Protamine Hagedorn) insulin in the morning and 1 unit in the evening.\nAfterwards, blood sample was obtained from the patient and sent to the laboratory of doctors Henrik Thybo Christensen and Klaus Brusgaard in H. O. Andersen Children's Hospital and Department of Clinical Genetics in Denmark. Then, genetic mutation analysis of KCNJ11 was performed. In the analysis method, deoxyribonucleic acid was extracted and amplified by polymerase chain reaction followed by bi-directional sequencing of the entire coding region. The genetic variation c. 602G >T, p.R201 L was found in a heterozygous form. This genetic variation had been previously described as pathogenic by Codner in 2005.\nAfter 2 months treatment with insulin, the treatment was switched from insulin to glibenclamide. At first, 0.1 mg/kg/day glibenclamide was given to the patient in the morning and at night. Then, based on the blood sugar level, glibenclamide was increased to 0.6 mg/kg/day. After treatment with glibenclamide, the patient's hyperglycemia was successfully controlled and he did not need insulin anymore. Now, the case is a 1-year-old infant with controlled hyperglycemia who only receives glibenclamide.