Fatal obstructive hypertrophic cardiomyopathy in two cases of neonatal congenital hyperinsulinism

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: SUN 596-623-Case Reports: Pediatric Endocrinology & Metabolism
Sunday, June 16, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board SUN-610
Michele M Zerah*1, Jennifer Anderson2, Jennifer Davenport3 and Paul Stephen Thornton4
1Presbyterian Medical Group, Albuquerque, NM, 2Pediatrix, Albuquerque, NM, 3Pediatrix, Albuquerque, 4Cook Children's Medical Center, Fort Worth, TX
Hypertrophic cardiomyopathy (HCM) is associated with many heritable conditions and genetic syndromes. The most commonly described neonatal association is with hyperinsulinism induced by gestational diabetes. After birth, with regression of hyperglycemia, the HCM resolves. HCM is also reported in other forms of hyperinsulinism such as in congenital hyperinsulinism (CHI) and Beckwith-Weidmann Syndrome (BWS). Hyperinsulinism has been successfully treated using diazoxide(DZX), however some postulate it may result in aggravation of the cardiomyopathy.

We report two cases of neonatal hyperinsulinism and HCM ultimately leading to early death.

Case 1: 32 week male infant with hypoglycemia at birth (Glucose <20mg/dl). Fetal ultrasound showed polyhydramnios, cystic hygroma with normal cardiac structure. Hypertrophic cardiomyopathy was diagnosed at day 12 and hyperinsulinism at d20; Insulin levels were 6 and 12 iu/ml for glucose level of 39 and 44 mg/dl respectively. His Glucose infusion rate (GIR) was 9 mg/Kg/min. He had no features of BWS. A Glucagon drip was initiated and blood glucoses stabilized prior to starting DZX at 5 mg/Kg /day, subsequently increased to 12.3 mg/kg/d. He was weaned off glucagon within 8 days and IV dextrose within 3 weeks. Rapidly progressive left ventricular obstruction developed at d60 despite normal blood glucose levels. DZX was discontinued, IV dextrose was reinstituted. He was transferred to a tertiary cardiac facility for further cardiac management. He died within 5 days of transfer from multisystem failure.

Case 2: 31 week female. The pregnancy was complicated by premature rupture of membranes, polyhydramnios and fetal ascitis. She was hypoglycemic at birth with massive abdominal distention. An ultrasound showed large cystic adrenals glands and ascitis. She had no dysmorphic features and her cardiac anatomy was normal with mild pulmonary hypertension. Insulin levels were 127uIU/ml and 300 uIU/ml for blood glucose of 41 mg/dl and 36 mg/dl respectively. A Glucagon drip was initiated on d6 because the GIR was 16.9 mg/kg/min. DZX was started on d7 at 15 mg/kg/day.  After 6 days, Glucagon and DZX were discontinued. She developed rapidly progressive HCM by D13 with deterioration of her clinical status. Support was withdrawn on d14 due to obstructive HCM (biventricular hypertrophy) and septic shock from klebsiella.  Histopathology of the placenta showed mesenchymal dysplasia (MD). The diagnosis of BWS was suspected and later confirmed because of the MD with cystic adrenals, hypoglycemia and polyhydramnios.

 Conclusion: Hypertrophic cardiomyopathy associated with hyperinsulinism states, can progress extremely rapidly. These two cases with fatal outcomes represent instances of obstructive HCM developing in matter of days. Early diagnosis and consideration of transfer to a specialized center for pancreatectomy may be key to preventing mortality in such patients.

Disclosure: PST: Consultant, Gate pharmaceuticals. Nothing to Disclose: MMZ, JA, JD

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm