Differential Diagnosis for Hyperammonaemia in Neonates
Single Most Likely Diagnosis
- Urea Cycle Disorders: These are a group of genetic disorders that result in the inability to remove ammonia from the body. They are a common cause of hyperammonaemia in neonates, with symptoms often presenting in the first few days of life.
Other Likely Diagnoses
- Organic Acidemias: Disorders such as methylmalonic acidemia and propionic acidemia can lead to hyperammonaemia due to the accumulation of toxic metabolites.
- Fatty Acid Oxidation Disorders: Conditions like medium-chain acyl-CoA dehydrogenase deficiency can cause hyperammonaemia, especially during periods of fasting or stress.
- Transient Hyperammonaemia of the Newborn: A condition characterized by temporary elevation of ammonia levels, often seen in premature or critically ill neonates.
Do Not Miss Diagnoses
- Inborn Errors of Biotin Metabolism: Although rare, disorders like biotinidase deficiency can lead to severe hyperammonaemia and require prompt treatment.
- Pyridoxine-Dependent Epilepsy: A condition that can cause seizures and hyperammonaemia, responding to pyridoxine supplementation.
- Glycogen Storage Disease Type I: Can cause hyperammonaemia due to the accumulation of lactic acid and other metabolites.
Rare Diagnoses
- Hyperinsulinism-Hyperammonaemia Syndrome: A rare condition caused by mutations in the GLUD1 gene, leading to excessive insulin secretion and hyperammonaemia.
- Lysinuric Protein Intolerance: A rare genetic disorder affecting amino acid transport, which can cause hyperammonaemia.
- Carbamoyl Phosphate Synthetase I Deficiency: A rare urea cycle disorder that can present with hyperammonaemia in neonates.