Reye's syndrome
GIB
UTI with a urease-producing organism (Proteus mirabilis)
Ureterosigmoidostomy
Shock
Severe muscle exertion/heavy exercise
Cigarette smoking
Transient hyperammonemia in newborns
Certain inborn errors of metabolism (urea cycle defects and organic acidemia)
Any cause of porto-systemic shunting of blood
Parenteral nutrition
After high-dose chemotherapy
Drugs such as:
Valproic acid
Barbiturates
Narcotics
Diuretics
Alcohol
Salicylate intoxication