The smell is associated with Protein and Ammonia.
At least this is my understanding.
"Fetor hepaticus or foetor hepaticus (see spelling differences), also known as breath of the dead or hepatic foetor, is a condition seen in portal hypertension where portosystemic shunting allows thiols to pass directly into the lungs. It is a late sign in liver failure and is one of the clinical features of hepatic encephalopathy."
If you read Newports post about Hepatic Encephalopathy you will see that it's associated with the liver not being able to process protein.
Which results in excessive ammonia.
Anyone with TMAU should get their Ammonia levels checked.