Fetor Hepaticus

What is fetor hepaticus?

Fetor hepaticus is a distinct smell on the breath of someone with liver disease. It happens when your liver can’t filter certain toxic substances from your blood anymore. These substances build up in your blood and come out in your breath. You may also detect the same smell in your pee or sweat.

Unlike common bad breath, fetor hepaticus isn’t related to what you eat, your oral hygiene or gum disease. It’s constant, and you can’t wash it away or treat the smell directly. But it’s important to see a healthcare provider about your underlying condition. Fetor hepaticus is a symptom of serious illness.

What does fetor hepaticus smell like?

Healthcare providers who recognize the smell of fetor hepaticus have described it as musty, pungent, oddly sweet and occasionally fecal (poop-like). While smells are somewhat subjective and hard to define, fetor hepaticus is different from other bad breath smells that can accompany other conditions.

Writers have compared it to:

• Rotten eggs and garlic.
• Freshly mown hay.
• Scorched fruit.

Fetor hepaticus is different from:

• Trimethylaminuria (fish odor syndrome). Trimethylaminuria, a buildup of trimethylamine in your blood, is a different metabolic condition. Although some people with liver disease may also develop trimethylaminuria, fish odor isn’t the dominant smell in fetor hepaticus.
• Uremic fetor (“ammonia breath”). An ammonia or bleach smell on your breath is a symptom of kidney failure. It happens when your kidneys stop filtering urea from your blood. Ammonia may play a small part in fetor hepaticus, but it’s not one of the dominant smells.
• “Keto breath.” A fruity or acetone smell (resembling nail polish remover) on your breath is a byproduct of ketosis, and sometimes, diabetes-related ketoacidosis. Some acetone may be in the mix of gases that make up fetor hepaticus, but it’s not the dominant smell.

What does fetor hepaticus mean?

Fetor hepaticus means “fetid liver” or “liver stench”. Of course, it’s not your liver itself that smells. But the smell does mean that your liver is failing to filter your blood as it should. This is usually a result of long-term (chronic) liver disease. Occasionally, an acute (temporary) condition may cause it.

Regardless of the specific cause, fetor hepaticus means that you need to seek healthcare right away. Your condition has reached a new and very serious stage. If toxins have accumulated in your blood at high enough levels to smell on your breath, they may begin to affect your brain and nervous system.

What causes the smell of fetor hepaticus?

Dimethyl sulfide and methyl mercaptan are probably the dominant smells in fetor hepaticus. Dimethyl sulfide has a pungent, garlicky smell, while methyl mercaptan smells more like rotten eggs or cabbage. Other possible contributors include ammonia, acetone, trimethylamine and certain ketones.

These substances (volatile organic compounds, or VOC) are natural byproducts of your metabolism. They circulate in your blood and come out in your pee, poop and breath. Usually, they aren’t so highly concentrated that you can smell them. That happens when your body isn’t clearing them well enough.

What conditions lead to fetor hepaticus?

The metabolic waste products that cause fetor hepaticus normally go to your liver for filtering. Blood from your digestive system travels to your liver through your portal vein. Your liver filters your blood and sorts the waste products into bile. The filtered blood then returns to your general circulation.

Fetor hepaticus means this process is failing. Either your liver isn’t filtering your blood effectively, or the blood carrying these waste products isn't going to your liver. In the first case, you have liver failure. In the second case, you have a portosystemic shunt. This means an abnormal connection has formed between your portal vein and other blood vessels in your body, allowing blood to bypass your liver.

Liver failure

Most people who develop fetor hepaticus have chronic liver failure, which is the end stage of chronic liver disease. It’s also known as decompensated cirrhosis. Cirrhosis means permanent scarring of your liver tissues. Decompensated means there’s so much scarring that your liver can’t function anymore.

Sometimes, acute liver failure can also cause fetor hepaticus. This is an urgent but possibly reversible condition. It happens when your liver is so overwhelmed by its immediate toxic load that it temporarily stops functioning. Whether you have acute or chronic liver failure, you should seek urgent care.

Portal hypertension

You might develop a portosystemic shunt that bypasses your liver if you have portal hypertension — high blood pressure in your portal vein. High blood pressure means your portal vein is backed up. Your body compensates for this by diverting the blood flow into other veins that go around the backup.

The most common cause of portal hypertension is, again, cirrhosis. So, most people with fetor hepaticus have both portal hypertension and chronic liver failure. But portal hypertension does have a few other possible causes, including blood clots, chronic heart failure, a liver infection called schistosomiasis and, rarely, liver cancer.

How do I know if I have fetor hepaticus?

Fetor hepaticus is a likely explanation for your bad breath if:

• It fits the description (musty and sweet, or like rotten eggs and garlic).
• It’s chronic (it’s lasted a while and doesn’t go away or keeps coming back).
• You already know (or suspect) that you have liver disease.

If you think you might have fetor hepaticus, check in with a healthcare provider. They might recognize the smell from experience. They’ll also take note of your other symptoms and your overall condition. If you don’t have a diagnosis yet, they’ll need to assess you for liver disease and portal hypertension.

What other symptoms might I have with fetor hepaticus?

Other signs and symptoms of liver failure include:

• Upper right abdominal pain.
• Jaundice (a yellow tint to your skin and eyes).
• Dark-colored pee and light-colored poop.
• Pruritus (itchy skin, but with no visible rash).
• Vision changes, like loss of night vision.
• Easy and excessive bleeding and bruising.

Other signs and symptoms of portal hypertension include:

• Swelling in your abdomen or in your legs and feet.
• Blood in your vomit or blood in your poop.
• Episodes of mild cognitive impairment or confusion (encephalopathy).

Is fetor hepaticus reversible?

Fetor hepaticus may go away if the condition causing it gets better. This will depend on the condition. If it’s an acute condition, treatment may cure it completely. If you have chronic liver failure, it isn’t curable except with a liver transplant. But treatment can sometimes improve the symptoms and side effects.

How long does fetor hepaticus last?

Fetor hepaticus will last for as long as your liver isn’t able to filter VOCs from your blood. If you can successfully treat this condition, fetor hepaticus will go away as your condition improves. If you can't, the symptom will continue to occur, although in some people, it seems to come and go in cycles.

Should this symptom be treated by a doctor or healthcare provider?

Fetor hepaticus is a sure sign that you should see a healthcare provider. Even if you already know that you have liver disease, fetor hepaticus is a warning sign that your condition is worsening. You need treatment to help slow the progress of the disease and prevent other life-threatening complications.

Life-threatening complications of chronic liver failure and portal hypertension can include:

• Acute, uncontrollable gastrointestinal bleeding.
• Hepatorenal syndrome (related kidney failure).
• Hepatopulmonary syndrome (related respiratory failure).
• Hepatic encephalopathy (cognitive and motor dysfunction).

Does fetor hepaticus indicate my prognosis or life expectancy?

Fetor hepaticus alone can’t determine your prognosis (outlook) because different conditions have different possible outcomes. Having chronic liver failure does limit your life expectancy, but the range can be from months to years. Your healthcare provider is the best person to assess your life expectancy.

A note from Cleveland Clinic

The ancient Romans called fetor hepaticus the “breath of the dead,” probably referring to the life-threatening nature of liver failure. They weren’t wrong. But while fetor hepaticus remains a reliable sign of chronic liver failure, fortunately, the treatment options have improved a bit since Roman times.

Chronic liver failure still isn’t reversible, but liver transplantation is now a possibility. We’re also better at managing the symptoms and side effects. Keeping in touch with your healthcare team and letting them know when new symptoms appear is one way you can help them stay on top of complications.