Consider ketotic hypoglycemia when evaluating infants and toddlers for hypoglycemia
Consider ketotic hypoglycemia when evaluating infants and toddlers for hypoglycemia: Excerpt from Avoiding Common Pediatric Errors
Author:
William Giasi, Jr., MD
What to Do - Interpret the Data
In infants and toddlers, signs and symptoms of hypoglycemia can often be
vague and subtle. Given the subtle and nonspecific findings of the signs and
symptoms, the detection of hypoglycemia is dependent on a high index of
suspicion.
Symptoms of hypoglycemia can be characterized into two physiologic
categories: activation of the autonomic nervous system characterized by an
adrenergic symptoms and neuroglycopenic (cerebral glycopenia) symptoms.
When serum glucose levels are <40 mg/dL, it may produce hunger and
trigger an adrenergic response. Common adrenergic symptoms include jitteriness, anxiety, sweating, tachycardia, pallor, weakness, nausea, and emesis. Neuroglycopenic symptoms include headache, dizziness, mental dullness, fatigue, difficulty concentrating, confusion, personality changes, visual
changes, seizures, and coma. Neonatal symptoms include those seen in children, such as tremors, jitteriness, and tachycardia, but may also present with
nonspecific signs, such as tachypnea, apnea, cyanosis, hypotonia, feeding
difficulty, abnormal cry, seizures, and coma.
Thedifferentialdiagnosisandmanagementofhypoglycemiaisextensive
andrequiresanunderstandingofthepathogenesis.Hypoglycemiamayresult
from disorders of gluconeogenesis, glycogen metabolism, lipid oxidation, or
amino acid metabolism.
The serum glucose should be measured to confirm hypoglycemia. Determining whether a patient isketotic isan important decision for generating
a differential diagnosis. There are two major categories: nonketotic hypoglycemia and ketotic hypoglycemia.
Those disorders that result in nonketotic hypoglycemia involve the inability to produce glucose and appropriate forms of energy despite appropriate glycogen storage. A prominent effect of insulin and counterregulatory
hormonesistosuppresslipolysisandketogenesis.Therefore,thoseetiologies
that involve high levels of insulin or lack of counterregulatory hormones do
not generate high levels of ketones. These etiologies include hyperinsulinism for islet cell adenomas or overproduction, infants of diabetic mothers,
congenital panhypopituitarism, congenital adrenal hyperplasia, fatty oxidation defects, and Beckwith-Wiedemann syndrome.
Hypoglycemia with resulting ketosis is often secondary to insufficient
glycogen stores. Etiologies include ketotic hypoglycemia, metabolic diseases
(galactosemia, hereditary fructose hypoglycemia, glycogen storage disease
type 1), ingestions (ethanol, insulin, salicylates, propanolol), liver failure,
and sepsis. Ketotic hypoglycemia is the most common etiology for hypoglycemia in children from 18 months to 5 years of age. The hypoglycemic
episodes occur most often when food intake is limited and the child experiences a prolonged fast; for example during periods of illness. Children
with ketotic hypoglycemia are frequently smaller than their peers and have
a history of transient neonatal hypoglycemia. The classic history is a child
who misses an evening meal and then is difficult to arouse the following
morning. In children with ketotic hypoglycemia, fasting for 12 to 18 hours
will result in hypoglycemia, ketonemia, and ketonuria. Normal children may
withstand fasting up to 24 to 48 hours, at which time they develop similar
symptoms.
The etiology and pathogenesis of ketotic hypoglycemia is unknown. It
is believed that there is a defect in complex process of protein catabolism.
The smaller muscle mass and defects in processing compromise the
supply substrates to gluconeogenic pathways, thus predisposing the patient to develop hypoglycemia more rapidly. The child with ketotic hypoglycemia will classically have ketonuria, ketonemia, appropriately low
levels of insulin, and low levels of serum alanine at the time of hypoglycemia. The presence of ketones is reflective of the child's inability to
use protein and the bodies' attempt to use alternative energy sources for
gluconeogenesis. Treatmentofketotichypoglycemiarequiresfrequent high-
protein, high-carbohydrate meals. In addition, during periods of illness
or a decrease in caloric intake, the child's urine should be monitored for
ketones.
It is important to emphasize that hypoglycemia is a symptom rather
than a diagnosis. Furthermore, because many of the signs and symptoms of
hypoglycemia are nonspecific and subtle, the clinician must maintain a high
suspicion for hypoglycemia. Laboratory evaluation may assist the clinician
in the establishing the etiology of the hypoglycemia. It is essential to confirm
thepresenceofhypoglycemiabymeasuringtheserumglucose.Furthermore,
it is critical at the time of hypoglycemia include a urinalysis, insulin, cortisol,
growth hormone levels, serum ketones, and electrolytes. Additional labs to
consider if metabolic etiologies are on the differential include ammonia,
lactate, free fatty acids, acylcarnitine profile, and organic acid. The history
and laboratory data can inform the differential diagnosis, evaluation, and
management.
Suggested Readings
Claudius I, Fluharty C, Boles R. The emergency department approach to newborn and childhood metabolic crisis. Emerg Med Clin North Am. 2005;23:843–883.
Gruppuso PA, Schwartz R. Hypoglycemia in children. Pediatr Rev. 1989;11(4):117–124.
Sperling M. Hypoglycemia. In: Behrman EM, Kliegman RE, Jenson HB, eds. Nelson Textbook
of Pediatrics, 17th ed. Philadelphia: Saunders; 2004:505–518.
Sperling MA, Menon RK. Differential diagnosis and management of neonatal hypoglycemia.
Pediatr Clin North Am. 2004;51:703–723.
Sunehag A, Haymond MW. Etiology of hypoglycemia in infants and children. UpToDate.
2007.
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Book Source Details
- Book Title: Avoiding Common Pediatric Errors
- Author(s): Anthony D Slonim MD, DrPH; Lisa Marcucci MD
- Year of Publication: 2008
- Copyright Details: Avoiding Common Pediatric Errors, Copyright © 2008 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Avoiding Common Pediatric Errors
Authors: Anthony D Slonim MD, DrPH; Lisa Marcucci MD
Publisher: Lippincott Williams & Wilkins
Copyright: 2008
ISBN: 0-7817-7489-6
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