From the Guidelines
An ammonia level of 94 is significantly elevated and requires immediate medical attention, with management focusing on lowering ammonia levels while addressing the underlying cause, typically liver dysfunction or urea cycle disorders. The management should prioritize the reduction of ammonia production and enhancement of ammonia clearance.
- Stop protein intake to reduce ammonia production.
- Administer i.v. glucose at an infusion rate of 8–10 mg/kg/min and i.v. lipids at 0.5 g/kg daily, up to 3 g/kg daily, to provide adequate calories and prevent catabolism, as recommended by 1.
- Consider the use of nitrogen-scavenging agents such as sodium benzoate and sodium phenylacetate, as well as urea cycle intermediates like l-arginine, as suggested by 1 and 1.
- Intravenous sodium benzoate and sodium phenylacetate should be given over 90–120 min as a bolus, then as maintenance over 24 h, with dosages based on body weight, as outlined in 1 and 1.
- Monitor the patient's mental status and provide supportive care, as ammonia levels this high may indicate hepatic encephalopathy.
- The patient may require hospitalization for close monitoring and management, with consideration of dialysis if ammonia levels remain elevated despite medical therapy, as recommended by 1 and 1. These interventions work by reducing ammonia production in the gut, enhancing ammonia clearance, and supporting the body's natural detoxification processes until the underlying cause can be addressed.
From the FDA Drug Label
Lactulose causes a decrease in blood ammonia concentration and reduces the degree of portal-systemic encephalopathy. Controlled studies have shown that lactulose solution therapy reduces the blood ammonia levels by 25 to 50%; The patient with an ammonia level of 94 should be managed with lactulose (PO) as it has been shown to decrease blood ammonia concentration and reduce the degree of portal-systemic encephalopathy 2, 2.
- The goal of treatment is to reduce the blood ammonia levels, which can be achieved with lactulose therapy.
- Lactulose has been shown to reduce blood ammonia levels by 25 to 50% in controlled studies 2.
From the Research
Management of Hyperammonemia
To manage an ammonia level of 94, several treatment options can be considered:
- Administration of intravenous calories as glucose and lipids to promote anabolism 3
- Carnitine to promote urinary excretion of urinary organic acid esters 3
- Correction of metabolic acidosis with the substitution of bicarbonate for chloride in intravenous fluids 3
- Administration of ammonia scavengers such as sodium benzoate or sodium phenylbutyrate 3, 4
- Treatment with N-carbamyl-L-glutamate to rapidly normalize ammonia levels by stimulating the first step of the urea cycle 3
Pharmacological Treatment
Pharmacological treatment options exist to improve urea cycle function or to remove nitrogen, but their use depends on the underlying disorder 5. Sodium benzoate can be used as a first-line ammonia scavenger for symptomatic hyperammonemia 4. Lactulose and rifaximin have a proven role as measures to use for secondary prophylaxis and are the mainstay of current therapy 6.
Importance of Timely Diagnosis and Treatment
Timely diagnosis and treatment of hyperammonemia are critical to prevent brain damage in affected patients 3, 5. Any delay in recognition and start of treatment of hyperammonemia may have deleterious consequences for the patient 5. Increased awareness of this condition and immediate start of appropriate therapy are of utmost importance 5.