increase blood levels of ammonia, usually the result of urea cycle abnormalities, produces a variety of symptoms, such as poor growth. irritability, lethargy, vomiting, anorexia, rapid breathing, disorientation, combativeness, coma, cerebral edema, and death if treatment is ineffective. Respiratory failure can occur in late-stage disease. There are clear signs of central nervous system involvement: poor coordination, hyper- or hypothermia (stiff or flaccid muscles), ataxia, tremor, seizures, decerebrate posturing (rigid extension of arms and legs)