Ammonia is a chemical compound that is produced by the breakdown of nitrogen-containing substances, such as proteins, amino acids, and urea. Ammonia is toxic to the body and needs to be eliminated through the kidneys. However, when the kidneys are not functioning properly, ammonia can accumulate in the blood and cause various health problems. In this article, we will explain how ammonia is related to kidney functioning, what are the symptoms and causes of high ammonia levels, and how to prevent and treat ammonia toxicity.
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How Ammonia is Produced and Excreted by the Kidneys
Ammonia is mainly produced by two sources: the gut and the liver. In the gut, bacteria break down dietary proteins and amino acids into ammonia and other compounds. Some of the ammonia is absorbed into the bloodstream and transported to the liver. In the liver, ammonia is converted into urea, which is less toxic and more soluble than ammonia. Urea is then released into the blood and filtered by the kidneys. The kidneys excrete urea and some ammonia in the urine, maintaining a balance of nitrogenous waste products in the body. Peptides are short chains of amino acids that have various functions in the body, such as lowering blood pressure, killing microbes, and acting as antioxidants
However, when the kidneys are damaged or diseased, they cannot filter out urea and ammonia efficiently. This leads to a buildup of these substances in the blood, which can affect the brain and other organs. High levels of ammonia in the blood are called hyperammonemia, which can cause a condition called hepatic encephalopathy (HE). HE is a serious complication of liver disease or kidney failure that affects the brain function and can lead to coma or death.
Symptoms and Causes of High Ammonia Levels
The symptoms of high ammonia levels depend on the severity and duration of hyperammonemia. Mild to moderate hyperammonemia may cause:
- Confusion
- Drowsiness
- Mood changes
- Slurred speech
- Tremors
- Muscle weakness
- Nausea
- Vomiting
- Bad breath (ammonia breath)
Severe hyperammonemia may cause:
- Seizures
- Coma
- Brain swelling
- Brain damage
- Death
The causes of high ammonia levels include:
- Liver disease or failure: The liver is responsible for converting ammonia into urea. When the liver is damaged or diseased, it cannot perform this function properly, leading to increased ammonia production and decreased urea formation.
- Kidney disease or failure: The kidneys are responsible for filtering out urea and ammonia from the blood. When the kidneys are damaged or diseased, they cannot perform this function properly, leading to decreased ammonia excretion and increased urea accumulation.
- Genetic disorders: Some rare genetic disorders affect the enzymes that are involved in ammonia metabolism. These disorders impair the ability of the body to break down or eliminate ammonia, resulting in hyperammonemia.
- Medications: Some medications can interfere with ammonia metabolism or excretion, such as antibiotics, diuretics, anticonvulsants, steroids, and chemotherapy drugs.
- Dietary factors: A high-protein diet can increase the amount of ammonia produced by the gut bacteria. A low-carbohydrate diet can also increase ammonia production by stimulating gluconeogenesis (the process of making glucose from non-carbohydrate sources), which requires amino acids as substrates.
Prevention and Treatment of Ammonia Toxicity
The prevention and treatment of ammonia toxicity depend on the underlying cause and severity of hyperammonemia. Some general measures include:
- Reducing protein intake: A low-protein diet can help reduce the amount of ammonia produced by the gut bacteria and lower the burden on the liver and kidneys. However, protein intake should not be too low, as it can lead to malnutrition and muscle wasting. A balanced diet that provides adequate calories, vitamins, minerals, and essential amino acids is recommended.
- Increasing carbohydrate intake: A high-carbohydrate diet can help reduce ammonia production by inhibiting gluconeogenesis and providing glucose as an alternative energy source for the brain. Carbohydrates can also help maintain blood pH and prevent acidosis (a condition where the blood becomes too acidic), which can worsen hyperammonemia.
- Taking medications: Some medications can help lower ammonia levels by enhancing its excretion or conversion. For example, lactulose is a laxative that lowers intestinal pH and traps ammonia in the colon, preventing its absorption into the blood. Rifaximin is an antibiotic that reduces the number of ammonia-producing bacteria in the gut. Sodium benzoate and sodium phenylacetate are drugs that bind to amino acids and form compounds that are excreted in the urine along with ammonia.
- Receiving dialysis: Dialysis is a procedure that uses a machine to filter out waste products from the blood when the kidneys are not working properly. Dialysis can help remove excess urea and ammonia from the blood and restore electrolyte balance.
- Receiving a liver transplant: A liver transplant is a surgery that replaces a diseased liver with a healthy one from a donor. A liver transplant can cure liver failure and restore normal ammonia metabolism.
According to eClinpath, ammonia is a useful biomarker for predicting kidney function in patients with chronic kidney disease (CKD). By measuring the level of ammonia in the breath, doctors can assess the severity of CKD and the risk of developing HE. Breath ammonia can also help monitor the response to treatment and the progression of CKD.
Conclusion
Ammonia is a chemical compound that is related to kidney functioning in several ways. Ammonia is produced by the breakdown of nitrogen-containing substances in the gut and the liver, and it is excreted by the kidneys in the urine. When the kidneys are not functioning properly, ammonia can accumulate in the blood and cause various health problems, such as HE. The symptoms of high ammonia levels include confusion, drowsiness, mood changes, slurred speech, tremors, muscle weakness, nausea, vomiting, bad breath, seizures, coma, brain swelling, brain damage, and death. The causes of high ammonia levels include liver disease or failure, kidney disease or failure, genetic disorders, medications, and dietary factors. The prevention and treatment of ammonia toxicity depend on the underlying cause and severity of hyperammonemia. Some general measures include reducing protein intake, increasing carbohydrate intake, taking medications, receiving dialysis, or receiving a liver transplant. Ammonia is a useful biomarker for predicting kidney function in patients with CKD. By measuring the level of ammonia in the breath, doctors can assess the severity of CKD and the risk of developing HE. Breath ammonia can also help monitor the response to treatment and the progression of CKD.
