Ammonia (NH) is a colorless irritant gas with a pungent order that is readily soluble in water to generate ammonium (NH) ions. Ammonia is a natural by-product in the human body as an intermediate in several metabolic reactions primarily involving amino acid synthesis. It also gets produced in the human gut as a result of various enzymatic actions of bacteria. However, as a result of the highly toxic nature of ammonia, it is quickly metabolized into urea in the liver by the urea cycle and excreted by the kidneys.
The blood ammonia level in a healthy adult is in a range of 15 to 45 micrograms/dL. Ammonia toxicity occurs when the ammonia content in the blood supersedes the liver’s capacity to eliminate it; this could be a result of either overproduction such as in congenital hyperammonemia or under-elimination such as in liver cirrhosis. This discussion will only focus on the various means by which the human body suffers exposure to external sources of ammonia and the multiple mechanisms of its toxicity.
The injury from ammonia commonly occurs via the following methods:
Inhalation of anhydrous ammonia gas or vapors of liquid ammonia
Ingestion of ammonia-containing liquids
Direct contact of anhydrous ammonia gas with skin or eyes
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