Type-I urea cycle defect: hypo or hyperventilation?

[LqdPls]

In the type-I urea cycle defect there is a CPS-I defect, therefore leading to hyperammonemia and CO2 build up. CO2 build up contributes to metabolic acidosis, but would the patient present with hypo or hyperventilation.

I understand that increased blood CO2 or acidosis is described as a hypoventilation state. But would the physician observe a patient who is hypoventilating or a patient who is hyperventilating (body trying to wash out the excess CO2)?

Thanks for the help

[Jeep23Guy]

You will understand this much better once you get to acid/base balance in physio (I suggest kaplan to learn this part...he makes it really simple).

Here are the basics: Because there is a metabolic acidosis, the body needs to compensate in some way. The compensation that occurs is hyperventilation in order to lower the pCO2 in the blood, thus, helping to raise the pH. Even though it's not necessarily wrong, I wouldn't really say that the patient is in a hypoventilated state because the acidosis is metabolic acidosis and not respiratory acidosis (although I guess you would understand that the hypoventilated state creates acidosis). So the presentation would be hyperventilation.

There's a lot more that could be said about this, but like I said, the acid/base part in physio should cover it (and you don't need to know that much for biochem).

[LqdPls]

So respiratory acidosis is the result of hypoventilation. Metabolic acidosis is the result of some metabolic deficiency, and is compensated by hyperventilation. Is this correct?

Thanks for help Jeep

[Jeep23Guy]

That's right, however, a metabolic acid/base disorder cannot be compensated fully by respiratory means.

[Banker794]

For example:

Diarrhea causes metabolic acidosis. However giving basic compounds po is not enough to correct the problem. Generally you want to provide 0.9% isotonic saline or some salt with lots of water to replenish the relative hypovolumia.

[hdu]

Please check in your patient with CPS-I defect, that UCD are characterized by hyperammonemia, encephalopathy and respiratory alkalosis.
The Respiratory alkalosis is a consequence of the hyperventilation.