Final answer:
Long-term treatment for an infant with symptoms suggesting a metabolic or hepatic disorder, including hyperammonemia and hypoketotic hypoglycemia, involves dietary management, supplementation, and possibly medications to manage ammonia levels, with regular monitoring of liver function.
Step-by-step explanation:
An infant who presents with acute lethargy, vomiting, palpable hepatomegaly, hyperammonemia, and hypoketotic hypoglycemia likely suffers from a metabolic or hepatic disorder necessitating immediate medical intervention and stabilization. Following acute management, long-term treatments may vary depending on the underlying condition but could include dietary modifications to reduce protein intake (to decrease ammonia production), supplementation with vitamins and cofactors, medications to reduce ammonia levels, and possibly liver transplantation in severe cases of liver dysfunction. Monitoring and managing potential complications such as hepatic encephalopathy will also be critical.
Maintaining stable metabolic conditions and preventing hyperammonemia crises are pivotal. These measures could involve avoiding fasting and infections that can precipitate metabolic decompensation. Additionally, treatment may involve the use of medications such as lactulose or antibiotics to lower gut ammonia production, as well as arginine or citrulline supplementation to enhance the residual function of the urea cycle. Frequent monitoring of liver function and metabolic parameters is necessary to adjust treatment as needed and avoid adverse outcomes.