NBME 2 block 2 Q 41 - stranger016

[ArchivalUser]

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, and plasma 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

i have no clue for this question

[ArchivalUser]

i think the answer is C..this is probably ornithine transcarbamylase deficiency...female carries can be varialbly affected ...

[ArchivalUser]

it is C urea cycle metabolic disorders

[ArchivalUser]

Many organic acid disorders present in the neonatal period. Typically, an affected newborn appears normal for the first days of life, but then may develop vomiting, poor feeding, failure to thrive, hypoglycemia, hyperammonemia, seizures, hypotonia and lethargy, progressing to coma. Common findings include ketosis, metabolic acidosis and, in some cases, an unusual odor.k