Hypoglycemia

Vandana Nayal, MD

Edited May 2005

Definition

Plasma glucose less than 40 mg/dl Immediate questions

1. Has a plasma blood sugar been sent to the laboratory?

2. Is the baby symptomatic?

3. Is the mother a diabetic?

4. How much glucose is the infant receiving?

Measurement of glucose

Bedside glucose strips can give incorrect values if the test is not done properly, if the strips used are too old, if the hematocrit is very high, or the glucose level is very low

There is a wide variation when compared to laboratory determined plasma levels– Glucose concentration in whole blood is 10-15%

lower than in plasmaALWAYS confirm your measurement in the lab

Symptoms of hypoglycemia

Apnea, hypotonia, irritability, irregular respirations, poor sucking or feeding, exaggerated Moro reflex, cyanosis, tremors, eye rolling, pallor, seizures, lethargy, temperature instability and coma

Rarely bradycardia, tachycardia, high pitched cry, tachypnea, and vomiting

Some have no symptoms despite documented hypoglycemia

Glucose requirement

How much glucose is the infant receiving in IV fluids?

Normal glucose requirement is 4-10 mg/kg/min

Check to be sure that calculations were correct

Causes of transient hypoglycemia

Perinatal stressSepsis, esp. Gram-negativeAsphyxia or HIEHypothermiaPolycythemiaShock Infant of diabetic motherDecreased glycogen stores Insufficient amount of glucose administeredMaternal meds: terbutaline, propranolol

Infants of diabetic mothers

40% of infants of diabetic mothers have documented hypoglycemia

Diabetic mothers have fluctuating hyperglycemia that results in fetal hyperglycemia– induces pancreatic B-cell hyperplasia =

hyperinsulism– after delivery, hyperinsulism persists and

hypoglycemia results

Decreased glycogen stores

Intrauterine growth retardation or small for gestational age

Premature infants Post-mature infants

Causes of persistent hypoglycemia

Hormone excess - hyperinsulism– Beckwith-Wiedemann syndrome– Islet cell adenoma– Beta cell hyperplasia, dysplasia– Nesidioblastosis

Beckwith-Wiedemann syndrome (because it is on the boards)

Macroglossia, Omphalocele, macrosomia, ear creases, mild to mod mental deficiency

Large kidneys with renal medullary dysplasia, pancreatic hyperplasia

Neonatal polycythemia,cryptorchidism, hypoglycemia(1/2 to 1/3 of cases) which is responsive to HC

Hepatomegaly, hemihypertrophy, (increased malignancy) hepatoblastoma, immunodeficiency

US and serial alpha feto protein every 6 months till the patient is 6 years of age to r/o Wilms’s and hepatoblastoma

Duplication of 11p15.5 causes BWS. IGF-2 gene localization to 11p causes BWS

Persistent hypoglycemia - hormone deficiencies

Growth hormone deficiencyACTH unresponsivenessThyroid deficiencyEpinephrine deficiencyGlucagon deficiencyCortisol deficiencyHypoplastic pituitaryHypothalamic hormone deficienciesMidline CNS malformation

Defects in carbohydrate metabolism

Glycogen storage disease type 1Fructose intoleranceGalactosemiaGlycogen sythase deficiencyFructose 1,6 diphosphatase deficiency

Defects in amino acid metabolism

Maple syrup urine diseasePropionic acidemiaMethylmalonic acidemiaTyrosinosis3-Hydroxy-3-methylglutaryl-CoA lyase

deficiency

Defects in fatty acid metabolism

Medium and long chain deficiency

Approach to hypoglycemia

History and physicalEvaluate infant for symptoms of

hypoglycemiaLook for signs of shock, sepsis, midline

defects, or Beckwith-Wiedemann syndrome

Laboratory studies for transient hypoglycemia

Serum glucose level should be sent to the lab to confirm the paper strip result

CBC with differential to evaluate for sepsis and to rule out polycythemia

Persistent Hypoglycemia

Initial studies – Serum glucose, insulin, cortisol, growth hormone at the time of hypoglycemic event; serum ketones

Ratio of insulin to glucose is obtained– level of >0.3 indicates a non hyperinsulinemic cause

of hypoglycemiaSerum ketones are low or absent in the presence

of hyperinsulinemia

Follow-up studies for persistent hypoglycemia

GH, Free Fatty acids, T3, T4, TSHGlucagon, uric acid, lactate, AlanineKetone levels before and 15 min after

administration of glucagon- 0.3mg/kg/doseUrine collection for AA, OA, catecholamines,

specific reducing sugarsSomatomedins (IGF-1, IGF-2, IGF binding

proteins)Ultrasound or CT scan of the pancreas

Management

Overall plan to maintain normoglycemia (level > 45 mg/dL)

Screen those at risk or those with symptoms suspicious for hypoglycemia – glucose check every 1-2 hr before feeds until

glucose levels are stable, then every 4 hoursDetermine why the baby is hypoglycemic

– obvious reasons or need further work up?

At risk?

PrematureSGA, LGABW < 2500 gSmaller of discordant twins (wt. Diff. > 25%)Asphyxiated infant (5 min Apgar < 5) Infants of massively obese mothers Infants of diabetic mothers Infants with polycythemia, infection,

microphallus/midline defects, anomalies associated with low glucose (BWS)

Asymptomatic hypoglycemia

Treatment is controversial Term infants, first 6-12 hrs, not high risk

– give early feeding Level < 25mg/dl is a medical emergency

– give parenteral glucose - 2-3 ml/kg D10W IV over 2-3 minutes

Check glucose q 15-30 minutes until stableAlways follow your institution guidelines

Symptomatic, persistent, or severe (< 25) hypoglycemia

If chemstrip values persist < 40 mg/dL or initial < 25 mg/dl (confirmed by stat lab level)– Give bolus and start a glucose infusion of 6mg/kg/min

even if the infant is asymptomatic Increase level of infusion until normoglycemia is

achieved (> 45 mg/dL)– Peripheral IV can take up to D13 otherwise will need

central accessCheck glucose levels q 15-30 minutes until stableDocument improvement in symptoms

Glucagon

If an intravenous line cannot be started, glucagon can be given to infants with adequate glycogen stores– Infants of diabetic mothers have good stores– less effective in IUGR or SGA

Dose is 300mcg/kg not to exceed1mg total dose subcutaneously or IM while vascular access is attempted

Other treatments

Trial of corticosteroids – Hydrocortisone sodium succinate mg/kg/day given

intravenously or orally every 12 hours– prednisone 2mg/kg/day

If hypoglycemia persists– Diazoxide (inhibits pancreatic insulin

release)m8-15mg/kg/day PO in 2-3 divided doses or IV 3-5mg/kg/dose repeat in 20 min if no effect

Somatostatin analog– Octreotide 2-10mcg/kg/day sc divided every 6-8h or

continuous IVHGH 0.1unit/day