11-24-2007, 04:50 PM
41. A 1-week-old newborn has had poor feeding,
vomiting, and
progressive lethargy over the past 4 days. She was
born at term; pregnancy,
labor, and delivery were uncomplicated, and she had no
congenital
anomalies. She is being breast-fed. She has a
healthy 2-year-old brother; a
sister died at 10 days of age after a full-term birth.
Examination
shows decreased muscle tone and poor responsiveness;
reflexes are normal.
Serum bicarbonate level is 8 mEq/L, pH is 7.15, andplasma ammonia
level is 10 times the upper limit of normal. Which of
the following is the
most likely cause?
A
) Mitochondrial disorder
B
) Mucopolysaccharidoses disorder
C
) Organic acid metabolism disorder
D
) Renal tubular acidosis
E
) X-linked leukodystrophy