Ammonia is released in our body as a result of the breakdown of amino acids and is converted into urea in the liver as a result of a chain of reactions called the urea cycle. Ammonia is produced from glutamine in the kidneys.

Ammonia is released in our body as a result of the breakdown of amino acids and is converted into urea in the liver as a result of a chain of reactions called the urea cycle. Ammonia is produced from glutamine in the kidneys. In the intestines, ammonia is released by the action of bacterial proteases, ureases, and amino oxidases on the contents of the colon and the hydrolysis of glutamine in the small and large intestines. The ammonia produced is sent to the liver, where it is converted to urea and excreted through the urine.

Ammonia is a colorless gas with a pungent odor. It has high solubility in water. It is toxic to human cells. Normal Limits: 10-65 umol/L or 17-110 mg/L. Ammonia elevation is an emergency. Ammonia levels should also be considered in patients with signs of tremor, dysarthria, blurred vision, coma, dehydration and tachypnea. Absence of high ammonia levels in individuals with these clinical findings does not exclude hepatic encephalopathy. Since ammonia is an easily volatile gas, it is recommended to send the blood sample to the laboratory preferably with ice. In fact, the blood sample should be taken from arterial blood vessels, not from venous blood vessels. Delaying the sample in the ammonia test can also increase its level in the blood.

Although ammonia is constantly produced in our tissues and organs, it is found at very low levels in the blood. This is because ammonia is rapidly removed by the formation of urea in the liver, and many tissues, especially muscles, release amino acid nitrogen as glutamine or alanine instead of free ammonia. Increased ammonia level (hypermonemia) is toxic to the central nervous system. Because ammonia can enter the central nervous system by passive diffusion. The rate of entry of ammonia into the central nervous system increases in direct proportion to the plasma ammonia concentration. Thus, it may cause a clinical picture called hepatic encephalopathy.

Hepatic encephalopathy is a clinical picture that causes confusion, drowsiness, and coma in advanced stages and can result in death if not treated. It is characterized by elevated ammonia in infants and children, recurrent vomiting, irritation and lethargy. If left untreated, it may result in convulsions, respiratory irregularity and coma.

In severe liver diseases, the rate at which the liver breaks down ammonia slows down. The amount of ammonia increases behind and may cause clinical problems.

In addition, if gastrointestinal bleeding occurs for any reason, blood accumulates in the intestinal cavity. Hemoglobin, which emerges during the cleaning and disintegration phase of this blood, is broken down by the intestinal flora and a large amount of ammonia is produced. This is why people with gastrointestinal bleeding often have a foul-smelling fart.

People on a protein-rich diet may also have a sudden increase in blood ammonia concentration if they have liver failure. Conditions that cause impaired hepatic blood circulation can also cause a sudden slowdown in the conversion of ammonia to urea, which can significantly increase the blood ammonia concentration.

Sudden increase in blood ammonia concentration and decrease in blood glucose level can be seen in Reye’s syndrome, which is especially seen in children and young adults who use aspirin during infections. It is reported that the peak value of blood ammonia level in Reye syndrome is related to the severity of the disease and the chance of survival of the patient.

In kidney failure or urinary tract infections that cause impaired renal blood flow, there may be an increase in blood ammonia concentration due to the slowdown in urea excretion.

High blood ammonia level is a condition that needs urgent intervention. If there is no acute liver failure in people with high blood ammonia levels, rarer causes such as drug side effects, infections and metabolic disorders should be considered. Serum ammonia concentrations may also be found to be high in people who receive total parenteral nutrition, people with uretero-sigmoidostomy, and patients using valproic acid.

Who is the ammonia test usually done on?

  • People with unexplained or unusual neurological symptoms
  • In people with hepatic dysfunction
  • Monitoring of ammonia-lowering therapy
  • Chemotherapy areas
  • Those receiving sodium valproate therapy
  • In patients with suspected inherited metabolic disease

The most common causes of high ammonia (hypermonemia) are:

  • Gastrointestinal Bleeding
  • Gastric Bypass
  • Multiple Myeloma
  • Allogeneic Stem Cell Transplantation
  • Glycine Poisoning (TURP Snd.)
  • Hunger
  • Watch
  • Hard Workout
  • Burn
  • Corticosteroid use
  • Urease Producing Infections (Proteus, Klebsiella)
  • Kidney diseases
    • Type 1 renal tubular acidosis
  • Infected Congenital Ureteral Occlusion
  • Liver failure and cirrhosis
  • Porto-systemic shunts in the liver
  • Toxins (Mushroom poisonings)
  • Medicines
    • Valproate
    • Carbamazepine
    • Topiramate
    • Salicylates
    • Rifampicin
    • Paracetamol
    • Halothane
    • Some Chemotherapeutics
  • Congenital causes
    • Urea cycle disorders and enzyme deficiencies
      • Carbamyl phosphate synthetase (CPS)
      • Ornithine transcarbamylase (OTC)
      • Argininosuccinate synthetase (AS)
      • Argininosuccinate lyase (AL)
      • Arginase N-Acetylglutamate synthetase
    • Organic Acidemias
      • Propionic acidemia
      • Methylmalonic acidemia
      • Isovaleric acidemia
      • β – Ketothiolase deficiency
      • Multiple carboxylase deficiency
      • Medium chain fatty acid acyl CoA dehydrogenase deficiency
      • Glutaric acidemia type II 3-Hydroxy-3-methylglutaric aciduria
    • Lysinuric protein intolerance
  • Hyperammonemia-hyperornithinemia-homocitrullinemia syndrome
  • Transient ammonia level of the newborn
  • Hyperinsulinism associated with neonatal ammonia elevation

If a high blood ammonia level is detected, the patient may need to be controlled with advanced tests such as blood sugar, lactic acid level, ketone levels in the urine and blood, and blood gases. It may also be necessary to evaluate for cerebral edema. Its extreme height may even suggest cirrhosis.