A 7-day-old neonate with an unremarkable hospital course, who now presents with increasing episodes of hypoglycemia, severe metabolic acidosis, recurrent vomiting, and high ammonia levels, should be evaluated for what disorder?

An infant presenting with hypoglycemia, metabolic acidosis, vomiting, and high ammonia levels should be assessed for urea cycle disorders, specifically Hyper-ammonemia type-I or type-II, which are inborn errors of metabolism where ammonia is not properly converted to urea.

Explanation:

A 7-day-old neonate presenting with increasing episodes of hypoglycemia, severe metabolic acidosis, recurrent vomiting, and high ammonia levels should be evaluated for urea cycle disorders. These symptoms are indicative of a potential inborn error of metabolism, specifically related to the urea cycle, which is responsible for converting toxic ammonia into urea. High levels of ammonia can indicate a deficiency in one of the cycle's enzymes, leading to ammonia intoxication.

Among the various disorders, two prominent types include:

Hyper-ammonemia type-I, which involves a deficiency of carbamoyl phosphate synthase-I, a familial disorder crucial for the initial step of the urea cycle.
Hyper-ammonemia type-II, due to a deficiency of ornithine transcarbamoylase, which is X-linked and characterized by elevated levels of glutamine in blood, CSF, and urine.

These disorders can be fatal if complete enzyme deficiency is present, and even partial deficiencies or reduced enzyme activity can lead to serious symptoms. Early diagnosis and intervention are critical for management and to prevent long-term damage or acute crises that are potentially life-threatening.