Examkin

Question

Difficulty: Very hardNeonatal Disorders

Evaluate the following four neonates presenting with hypoglycemia or severe metabolic derangements within the first two weeks of life. Connect each patient's specific clinical and laboratory profile to the most likely underlying endocrine or metabolic etiology.

  • A 33-day-old male neonate presents with recurrent severe hypoglycemia (2525 mg/dL) and undetectable serum ketones. Physical examination is notable for a midline cleft lip, single central incisor, and a stretched penile length of 1.21.2 cm (< 55 th percentile).Congenital hypopituitarism
  • A macrosomic infant develops refractory hypoglycemia requiring a continuous intravenous glucose infusion rate of 1616 mg/kg/min. Examination reveals an omphalocele, macroglossia, and asymmetric enlargement of the right lower extremity.Beckwith-Wiedemann syndrome
  • A 1212-day-old phenotypically normal male infant presents with poor weight gain, recurrent emesis, and lethargy. A basic metabolic panel reveals a serum sodium of 122122 mEq/L, potassium of 6.86.8 mEq/L, and glucose of 4242 mg/dL.21-hydroxylase deficiency
  • A 44-day-old infant develops severe hypoglycemia and hepatomegaly. Laboratory evaluation reveals a high anion-gap metabolic acidosis with elevated serum lactate, profound hyperuricemia, and hypertriglyceridemia.Glucose-6-phosphatase deficiency

Answer

The clinical profiles match respectively to: congenital hypopituitarism (midline defects, micropenis, hypoketotic hypoglycemia), Beckwith-Wiedemann syndrome (hyperinsulinism, hemihypertrophy, omphalocele), 21-hydroxylase deficiency (salt-wasting crisis in a phenotypically normal male), and glucose-6-phosphatase deficiency (hypoglycemia with lactic acidosis and hyperuricemia).
Each neonate presents with a highly specific pattern of symptoms that isolates a single endocrine or metabolic defect. Congenital hypopituitarism causes hypoketotic hypoglycemia combined with midline defects (cleft lip, micropenis). Beckwith-Wiedemann syndrome is identified by hyperinsulinism paired with macroglossia, omphalocele, and hemihypertrophy. The 21-hydroxylase deficiency causes a salt-wasting adrenal crisis at 1-2 weeks of life, which is uniquely covert in males because they lack ambiguous genitalia. Finally, Glucose-6-phosphatase deficiency (Von Gierke disease) is distinguished by severe hypoglycemia accompanied by lactic acidosis, hyperuricemia, and hypertriglyceridemia.

Step-by-Step Solution

1
Analyze the first neonate's presentation of hypoglycemia with undetectable ketones, midline facial defects, and micropenis.
Identifies a failure of the pituitary axis (Congenital hypopituitarism).
Growth hormone and cortisol are essential counter-regulatory hormones; their absence causes fasting hypoglycemia. Concomitant LH/FSH deficiency results in an underdeveloped phallus.
2
Evaluate the second neonate's macrosomia, high glucose requirement, and distinct physical exam findings (omphalocele, hemihypertrophy).
Diagnoses Beckwith-Wiedemann syndrome.
While infants of diabetic mothers also have macrosomia and hyperinsulinemic hypoglycemia, the presence of hemihypertrophy and an omphalocele is unique to the genetic overgrowth condition Beckwith-Wiedemann syndrome.
3
Assess the third neonate's presentation of isolated hyponatremia, hyperkalemia, and hypoglycemia at nearly two weeks of age.
Identifies 21-hydroxylase deficiency.
Male infants lack the ambiguous genitalia that often trigger early screening in females. They appear normal at birth and present covertly with a life-threatening salt-wasting adrenal crisis due to aldosterone and cortisol deficiency.
4
Review the fourth neonate's specific biochemical derangements (lactic acidosis, high uric acid, high triglycerides) alongside hypoglycemia.
Diagnoses Glucose-6-phosphatase deficiency.
This specific metabolic triad perfectly differentiates Type I Glycogen Storage Disease from other metabolic causes of hepatomegaly and hypoglycemia.

Key Concept

Differentiation of neonatal endocrine and metabolic emergencies relies on pairing hypoglycemia with subtle syndromic physical features (e.g., midline defects, hemihypertrophy), specific electrolyte derangements (salt-wasting), or unique biochemical profiles (lactic acidosis, hyperuricemia).
Rate this question

Topics

Neonatal Disorders

More questions from this topic