History
Glucose is normally the primary source for brain energy. The brain can also use ketones, but this transition is gradual. Symptoms of hypoglycemia reflect 2 major clinical pathways. The first pathway is caused by activation of the autonomic nervous system, which causes symptoms such as sweating, trembling, flushing, anxiety, heart pounding, and hunger. The second group of symptoms is due to neuroglycopenia and includes an inability to concentrate, confusion, tiredness, feeling tearful, difficulty speaking, behavioral changes, incoordination, weakness, and drowsiness. Nonspecific symptoms include mouth tingling, dry mouth, blurred vision, headache, and nausea. These symptoms, of course, vary according to the age of the patient.
Neonates
Signs and symptoms of hypoglycemia in neonates include the following:
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Tremulousness
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Brisk Moro reflex
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Lethargy
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Poor feeding
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Irritability
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Hypothermia
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Respiratory distress
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Apnea
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Bradycardia
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Seizure
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Coma
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Sudden death
Older children
Signs and symptoms of hypoglycemia in older children include the following:
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Dizziness
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Sweating
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Hunger
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Anxiousness
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Confusion
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Lethargy
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Poor feeding
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Irritability
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Seizure
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Coma
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Sudden death
Physical Examination
Hypoglycemic reactions are usually, but not always, accompanied by an increased heart rate with bounding pulse due to increased epinephrine secretion. Infants, if awake, may be irritable, tremulous, and cranky.
If the brain’s energy supply is severely impaired, the patient's mental status is likely to be impaired, with extreme inappropriate affect and mood, lethargy, seizure, or coma.
Large body size for age in the neonate or older child suggests hyperinsulinism, although some children with hyperinsulinism are born prematurely and are small for gestational age. Decreased subcutaneous fat suggests inadequate glucose stores. Poor linear growth may point to growth hormone deficiency, and midline facial and cranial abnormalities suggest pituitary hormone deficiencies, as does micropenis in a male. Liver size should be assessed for evidence of glycogen-storage diseases.
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Normal hypoglycemic counterregulation.
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Interpretation of the critical sample.
