From the Guidelines
An ammonia level of 50 μmol/L in adults is considered elevated and requires immediate medical attention to prevent potential brain damage and hepatic encephalopathy. The management of elevated ammonia levels should focus on treating the underlying cause, which is often related to liver dysfunction. According to the most recent guidelines, routine measurement of ammonia levels for diagnosis is not recommended 1, as ammonia levels can be variable and may not accurately reflect the presence of hepatic encephalopathy (HE). However, a low ammonia level in patients with coma or confusion should point toward etiologies other than HE.
Treatment Approach
Treatment of elevated ammonia levels typically involves:
- Lactulose 25-30 mL orally every 1-2 hours until bowel movements occur, then 15-30 mL 2-3 times daily to maintain 2-3 soft bowel movements per day
- Rifaximin 550 mg twice daily may be added for recurrent episodes
- Dietary protein restriction to 0.8-1.2 g/kg/day, although protein restriction is now considered detrimental, except perhaps, for very short periods of time, in patients with severe overt HE and gastrointestinal bleeding 1
- Addressing precipitating factors like dehydration, infection, or medication effects are essential
Nutritional Considerations
- Patients with HE should avoid long periods of fasting and should be encouraged to split their caloric and protein intake into small, frequent meals 1
- The type of protein ingested may be important, with dairy/vegetable protein potentially being better tolerated than meat protein 1
- BCAA supplements, in daily divided doses, may facilitate the provision of an adequate nitrogen intake in patients who are intolerant to meat protein 1
Monitoring and Follow-up
Regular monitoring of ammonia levels and mental status is crucial during treatment. Immediate medical evaluation is necessary as untreated hyperammonemia can cause brain damage. Patients should avoid protein-rich foods, medications that increase ammonia (e.g., certain diuretics), and should stay well-hydrated.
From the FDA Drug Label
Controlled studies have shown that lactulose solution therapy reduces the blood ammonia levels by 25 to 50%; The FDA drug label does not answer the question about what an ammonia level of 50 means in adults.
From the Research
Ammonia Levels in Adults
- The normal blood concentration of ammonia is approximately 30 µM 2.
- Hyperammonemia is a condition where ammonia levels are elevated, and it can cause central nervous system abnormalities 3.
- Ammonia levels of 39 μmol/L have been reported to cause acute metabolic encephalopathy, which can be resolved with fluid bolus and maintenance fluid 4.
Treatment of Hyperammonemia
- Lactulose and rifaximin are commonly used to treat hyperammonemia in patients with liver disease 5, 2, 6.
- Rifaximin has been shown to reduce the recurrence of overt hepatic encephalopathy episodes and improve health-related quality of life 5.
- Lactulose may enhance ammonia uptake by small bowel bacteria, while the mechanism of action of rifaximin is unclear 2.