Question

Please read carefully the following case study and provide a suitable answer to its questions.

A male baby born after a normal pregnancy appeared to be healthy until after the third day after his birth. He became lethargic, hypnotic (low muscle tone), his breathing was shallow and lead to apnea. First, he was hooked up to a mechanical respirator. A blood sample was taken to the lab and found that his plasma ammonia level was 474 µmol/L.

As a healthcare provider, you have put the baby under peritoneal dialysis until results of plasma amino acid levels and urine organic acid tests are ordered. The baby went into a deep coma.

The lab tests revealed the following;

Plasma ammonia	474 µmol/L
Plasma glutamine	1560 µmol/L (normal value 350 – 700 µmol/L)
Plasma arginine	Undetectable
Plasma N-acetylglutamine (NAG)	High
Plasma PH level	7.9

Based on the above lab result;

1. What is your diagnosis of this case? Provide a suitable reason to your answer along with the specific reaction (equation) of urea cycle on which you are referring to on your answer.

2. Why the patient has high blood level of glutamine?

3. Why the patient has high plasma level of NAG?

4. How can you treat this condition and save the baby from a life-threatening coma?

5. What type of condition is this? (Congenital or Acquired)

Answer 1

Ans 1.Urea cycle defect---- Carbamyl phosphate synthetase I (CPS I) deficiency

In the presence of N -acetylglutamate, ammonium ions combine with bicarbonate to form carbamoyl phosphate. The reaction takes place in hepatic mitochondria.

lt is a congenital disorder (Autosomal recessive)

Emergency Treatment involves removal of excessive ammonia by dialysis. Once the levels of ammonia is near normal treatment involves compound that increase the removal of nitrogen waste. These compounds convert nitrogen into products other than urea, which are then excreted; hence, the load on the urea cycle is reduced. The first compounds to be used were sodium benzoate and arginine and phenylbutyrate.