Plasma ammonia concentrations are often a cause for concern and treatment may be very urgent. The symptoms are highly variable. Neonates often have an overwhelming illness, although respiratory alkalosis is an early sign. In infants the symptoms are more often ‘gastro-intestinal’ such as vomiting and anorexia combined with slow developmental progress. In older children neurological symptoms usually predominate with episodes of encephalopathy, often combined with slow developmental progress.
Sections of this guideline include: interpretation, investigations, management, differential diagnosis.