Endocrine Abstracts

JOINT2728

Background: Congenital porto-systemic shunt (CPSS) between the portal vein and the inferior vena cava is a very rarely described cause of alternating pathological fasting ketotic hypoglycemia (pKH) and hyperinsulinemic hypoglycemia (HH).

Methods: Case reports.

Results: In two male patients aged 14. 9y, and 7. 0y, respectively, a CPSS was identified. Patient 1 was diagnosed with fasting pKH age 5y. Glucose did not increase after i. m. glucagon. Unsuppressed serum insulin during hypoglycemia and chronic zink deficiency were recorded. Ammonia was persistently elevated (80-120 mcM); other liver counts were only slightly affected. Plasma amino acids indicated liver affection with increased tyrosine and methionine. IgF-1 and IgF-BP3 were low despite normal growth hormone (GH) stimulation test and IgF1 only increased to 120 mg/l upon IgF1 stimulation test. Synacthen test showed low cortisol response with low ACTH. MRI of the pituitary and related structures was normal. Other hormonal, extensive metabolic, and expanded genetic studies returned normal. Treatment variably included extended release cornstarch, diazoxide, long-acting somatostatin analogue, GH and hydrocortisone. Repeat abdominal ultrasound showed discrete hepatic changes. MRI and contrast CT identified an intrahepatic CPSS. Radiological shunt closure at the age of 15 y led to normalization of blood glucose, ammonia, zink deficiency and hormonal disturbances without further treatment. Patient 2 was diagnosed with pKH age 3y with later diagnosis of mild hyperinsulinism. Except for slightly decreased coagulation factors II-VII-X, liver biochemistry was normal including ammonia. He had persistent, unexplained iron deficiency anemia, refractory to oral supplementation. He had prominent veins on the anterior truncus and a tendency to declive edema. Blood pressure and echocardiography were normal. Synacthen test was flat with low ACTH. IgF1 and IgF-BP3 were low with low IgF1 response upon IgF1 generation test. GH stimulation tests, other hormonal tests, MRI of the brain and pituitary and intensive metabolic and genetic investigations were normal. Treatment included extended release cornstarch, diazoxide, GH, hydrocortisone and iron. Abdominal ultrasound identified a very narrow portal vein and an extrahepatic CPSS was diagnosed by contrast CT. A first trial of radiological shunt balloon occlusion was unsuccessful due to reduced portal venous flow with unacceptable elevation of pressure in the hepatic vein.

Conclusion: CPSS should be suspected in children with alternating pKH and HH, liver affection and variable other manifestations. Ultrasound followed by contrast CT of the abdomen is diagnostic. The hypoglycemia, low IgF1 and IgF-BP3 and blunted ACTH-cortisol axis can normalize after shunt closure.