Why Does Urine Smell Like Maple Syrup?

Most variations in urine odor are temporary and do not indicate illness. Vitamins, as well as some meals and medications, can impact the smell of your urine. For instance, eating asparagus produces a strong urine smell.

Urine that smells bad might be caused by germs. Urine with a sweet fragrance could indicate uncontrolled diabetes or a rare metabolic disorder. Urine with a musty odor can be caused by liver illness and several metabolic conditions.

Why does my son’s urine have a syrupy odor?

Uncontrolled diabetes patients may have dangerously high blood glucose levels. The urine may smell sweet as the body attempts to eliminate the additional glucose.

People with diabetes who have sweet-smelling urine may also have the following signs and symptoms:

  • exhaustion
  • severe thirst
  • changes in appetite
  • unaccounted-for weight loss

Diabetic ketoacidosis

Without enough insulin and typically, but not always, with extremely high blood sugar levels, this disease develops.

Insulin aids in the body’s utilization of glucose for energy. The breakdown of fat occurs when the body is unable to create enough insulin to utilise glucose. Ketones, an acid, build up in the blood as a result.

Diabetes-related ketoacidosis should be treated immediately because it can be lethal if not.

Type 1 diabetics are more likely to have the illness, while type 2 diabetics might also experience symptoms.

A person may also have the following signs in addition to pee with a pleasant smell:

  • the breath smells nice
  • I’m feeling worn out
  • confusion
  • seizures

Maple syrup urine disease

maple sugar A hereditary illness called urine disease prevents a person from processing some proteins. It is an inherited condition, and parents may discover that their child or infant has urine with a sweet fragrance.

If this condition is not treated, it could be fatal. Less severe manifestations of the illness can manifest in children. There is a cure for maple syrup urine illness. When a child has pee that smells sweet, parents should get them to the doctor right away.

What is the outlook for patients who have maple syrup urine disease (MSUD)?

By maintaining a rigorous diet and avoiding illness and stress as much as they can, people with MSUD can develop into adults. Although a protein-restricted diet and regular medical supervision can help manage the illness, MSUD sufferers are always at danger of a metabolic episode. At any time, symptoms can abruptly recur. Usually this happens after the person:

  • becomes infected.
  • does not eat for a long period of time (fasts).
  • goes through trauma or stress (either physical or psychological).
  • changes their diet or doesn’t adhere to the advised diet.

People with MSUD must seek medical assistance right soon if they experience a metabolic attack. The danger of brain damage and other consequences can be decreased with immediate care. Discuss the option of a liver transplant with your doctor.

Does pee smell after consuming maple syrup?

The stench is the most obvious and recognisable sign of MSUD. People with MSUD frequently experience a sweet fragrance resembling maple syrup or burnt sugar in their sweat, earwax, and urine.

For each case of the illness and each form of MSUD, the quantity and intensity of symptoms vary.

Babies with untreated classic MSUD may become more agitated, sleep for longer periods of time or in different positions, and have trouble breathing and feeding. Additionally, they might experience muscle spasms, lose consciousness, or cease breathing altogether. They are susceptible to physical, mental, and developmental delays as they age.

Any age can experience intermediate, sporadic, and thiamine-responsive MSUD symptoms. When you are ill or under stress, MSUD symptoms might occasionally appear or get worse. Symptoms in adults or older children include:

  • abdominal pain
  • Vomiting
  • Anorexia and losing weight
  • weakness or loss of control of the muscles
  • uncontrollable motions
  • Unsteady speech
  • alterations in consciousness or difficulty staying vigilant

How does diabetic urin smell?

What scent does diabetic urine have? Urine that smells sweet or fruity is one indication that a person may have diabetes or high blood sugar. The sweetness in your urine is caused by sugar and indicates that your body is attempting to eliminate surplus sugar in your blood.

Why am I getting a maple syrup odor?

The condition known as maple syrup urine disease (MSUD) is characterized by the body’s inability to digest specific protein components. People who have this illness may have urine that smells like maple syrup.

Is maple syrup urine illness treatable?

A uncommon genetic illness known as maple syrup urine disease results in the baby’s urine having the distinct aroma of maple syrup because the body is unable to correctly digest amino acids. Maple syrup urine disease (MSUD) can be life-threatening as early as the first two weeks of life if it is not identified and treated quickly after delivery.

Early detection and treatment are so crucial. A customized diet that breaks down the three specific amino acids—leucine, isoleucine, and valine—and prevents them and their harmful byproducts from accumulating excessively in the blood may usually be used to manage MSUD. Even with treatment, some children with this illness can experience severe paralysis and impairment.

The majority of the time, MSUD is identified at birth as part of the regular newborn screening procedures that are mandated in many states. All newborns must be screened for maple syrup urine illness in Pennsylvania, New Jersey, and Delaware. The baby’s blood is drawn from the heel and examined for abnormally high quantities of amino acids. Babies that undergo early metabolic screening tests and obtain abnormal findings may be referred to the Children’s Hospital of Philadelphia’s Newborn Metabolic Screening Program.

One in 185,000 babies are thought to be affected with MSUD worldwide. Compared to the general population, MSUD is more prevalent among Mennonites. According to estimates, 1 in 380 Old Order Mennonites and 1 in 26,000 Ashkenazi Jews are thought to suffer from MSUD. The number of Americans who have received an MSUD diagnosis is around 2,000.

What scent does UTI urine have?

However, food alone cannot account for all uncommon urine odors. According to Dr. Bajic, the stinky stream might occasionally be a sign of a serious health problem that has to be addressed.

For illustration:

Pee that smells like ammonia

A urinary tract infection may be indicated if you find a trace of ammonia in your urine. The smell indicates the possibility of germs in your urinary system, most commonly in your urethra, kidneys, or bladder.

Additionally, urine exhibiting UTI symptoms may be hazy or even somewhat crimson. In addition to becoming painful, urinating may also become a symptom that you experience more frequently. Other tell-tale concomitant symptoms include a fever and mental disorientation.

According to Dr. Bajic, 10 million Americans visit the doctor each year for antibiotic therapy due to the prevalence of UTIs. The illness is more common in women and older people.

Other possible reasons of urine that smells ammonia-like include:

How does maple syrup urine illness manifest itself?

The MSUD Family Support Group, Madeline Zupan, an editorial intern from the University of Notre Dame, Neil R. M. Buist, MD, Professor Emeritus, Pediatrics and Medical Genetics, Oregon Health & Science University, and NORD are all gratefully acknowledged for their contributions to the creation of this report.

General Discussion

An enzyme complex called branched-chain alpha-keto acid dehydrogenase, which the body needs to break down (metabolize) the three branched-chain amino acids (BCAAs) leucine, isoleucine, and valine, is lacking in maple syrup urine disease (MSUD), a rare hereditary illness. All three BCAAs, as well as a number of their hazardous byproducts (particularly their respective organic acids), accumulate abnormally as a result of this metabolic failure. Within a few hours of birth, plasma concentrations of BCAAs start to increase in the classic, severe form of MSUD. Symptoms start to appear if left untreated, frequently within the first 24 to 48 hours of life.

Lethargy, irritability, and poor feeding are among the non-specific indications of developing neurological dysfunction that characterize the initial presentation. Soon after, focal neurological signals such aberrant movements and increased spasticity appear, followed by seizures and a deepening coma. Without treatment, brain damage progresses inevitably and usually results in death within a few weeks or months. The only distinguishing symptom of MSUD is the emergence of a distinctive odor, resembling maple syrup, which can be noticed as early as a day or two after birth and is most easily recognized in the urine and earwax. Leucine’s detrimental effects on the brain and the severe ketoacidosis brought on by the buildup of the three branched-chain ketoacids are the causes of the toxicity (BCKAs).

Through the use of a customized diet in which the three BCAAs are strictly monitored, the disorder can be successfully managed. However, even after receiving medication, MSUD patients of any age continue to have a significant chance of experiencing acute metabolic decompensation (metabolic crises), which are frequently brought on by an accident, an illness, a lack of food (fasting), or even psychological stress. A quick, sharp surge in amino acid levels occurs during these episodes, demanding immediate medical attention.

The classic type, intermediate type, intermittent type, and maybe a thiamine-responsive type are the three or even four different kinds of MSUD. The varying severity and age of onset of each of the four MSUD subtypes are caused by varying levels of residual enzyme activity. All kinds have an autosomal recessive pattern of inheritance.

In the US and many other nations, newborns are screened for MSUD, ensuring that the majority of such infants are found through these programs. Infants with MSUD typically appear with increasing neurological symptoms when such screening is unavailable. If properly and regularly carried out, early diagnosis and treatment can significantly reduce the risk of serious long-term consequences while stabilizing the infants.

Signs & Symptoms

The degree of remaining enzyme activity has a significant impact on the symptoms and severity of MSUD, which differ widely from patient to patient.

The most prevalent and severe form of MSUD is known as “classic” and is characterized by little or no enzyme activity. Within two to three days, most newborns with classic MSUD begin to exhibit modest, non-specific symptoms. These symptoms include poor feeding at the breast or bottle as well as growing tiredness and irritability. The infant further disengages as the deterioration progresses, and then begins to display increased focal neurologic symptoms, such as aberrant movements along with growing hypertonia and stiffness, leading to seizures and coma. Extreme hypotonia episodes may occur briefly. In the end, respiratory failure and death result from central neurologic failure. By the time the first signs appear, cerumen, sweat, and urine may all have a unique maple syrup odor. This is formed from one of the BCKA organic acids that build when the disorder spirals out of control and is derived from its specific BCAA. Typically, during periods of metabolic stability, the odor is undetectable.

There is a lifelong risk of rapid or gradual recurring metabolic decompensation after the condition has been treated and stabilized, which would bring back all the symptoms typical of untreated cases. Dietary intake of BCAAs needs to be closely regulated and observed. However, metabolic crises can still happen even if dietary intake is unchanged due to an imbalance between the enzyme’s inherent residual activity and higher BCAAs release of protein from tissues as a result of enhanced breakdown (catabolism). During any metabolic load, such as infection, even if only minor, psychological or physical stress, trauma, or starvation, a rising catabolic rate may appear gradually or may emerge suddenly. The appearance of the symptoms that are characteristic in an untreated case and are caused by high BCAAs, particularly leucine and the three accompanying BCKAs, characterize these episodes. Every episode has the potential to develop into a metabolic crisis and needs to be handled much like any episode in a baby. Aspects of attention deficiency hyperactivity disorder (ADHD), impulsivity, anxiety and/or depression, seizures, and intellectual disability may all manifest in people with classic MSUD.

Inflammation of the pancreas and generalized loss of bone mass (osteoporosis), which can increase the risk of fractures, are additional side effects of classic MSUD (pancreatitis). Intracranial hypertension, which causes some people to have increased pressure in their skulls and results in excruciating headaches that are occasionally accompanied by nausea and vomiting.

Greater levels of residual enzyme activity than those seen with classic MSUD are characteristics of intermediate MSUD. The majority of children are diagnosed between the ages of five months and seven years old, while the start and symptoms of intermediate MSUD may be neonatal. Lethargy, feeding issues, poor growth, ataxia, and acute metabolic crises that cause seizures, comas, brain damage, and, in rare instances, life-threatening neurological consequences are among the symptoms that, when they do occur, are comparable to those of the classical type. It should be underlined that people with Intermediate MSUD are equally prone to severe acidosis and neurologic sequelae as those with Classic MSUD. The earwax, sweat, and urine all have the distinct maple syrup smell. Some affected kids might not show any symptoms until much later in life. The fundamentals of disease management apply to both.

Normal growth and intellectual development are typical features of intermittent MSUD, and those who are affected frequently can tolerate normal dietary protein intake. The same stimuli as in classical MSUD cause the symptoms. MSUD with a thiamine reaction responds to thiamine therapy (vitamin B1). The BCAA enzyme complex includes thiamine. Thiamine-responsive MSUD seldom manifests in the newborn period and shares intermediate MSUD’s symptoms and clinical trajectory. Infants with the condition react to high doses of thiamine, which increases recurrent enzyme activity. No patient with thiamine-responsive MSUD has ever been treated exclusively with thiamine; instead, they often combine thiamine with a diet that restricts their protein intake.

Several families with numerous affected members have been uncovered who do not meet the requirements for any of the aforementioned subtypes, despite the fact that the majority of patients fall into the aforementioned categories. These special patients are categorized as MSUDs (unclassified).

It should be stressed that the absence of the maple syrup scent does not rule out the diagnosis of MSUD in the context of such seemingly non-specific neurologic symptoms.


Changes (mutations) in one of three distinct genes—BCKDHA, BCKDHB, or DBT—are the root cause of MSUD. Human BCKAD enzymes, which are part of the branched-chain alpha-ketoacid dehydrogenase complex, are lacking or have reduced activity as a result of mutations in these genes. All proteins contain the branched chain amino acids leucine, isoleucine, and valine, which are broken down by these enzymes. The severe health issues linked to MSUD are caused by the buildup of these amino acids and their harmful derivatives (ketoacids). Leucine is the only one of these amino acids that is poisonous, which is why extra valine and isoleucine are frequently provided during treatment. Acidosis in the metabolism is caused by the buildup of each ketoacid.

MSUD is inherited autosomally recessively. When a person inherits a dysfunctional gene from each parent, they develop recessive genetic diseases. An individual will be a carrier for the disease if they have one working gene and one non-working gene for it, but they often won’t exhibit any symptoms. With each pregnancy, there is a 25% chance that two carrier parents will also carry the non-working gene and, as a result, have a child that is affected. With each pregnancy, there is a 50% chance that the unborn kid will also be a carrier, like the parents. A child has a 25% chance of inheriting functional genes from both parents. Both men and women are at the same level of danger.

Affected Populations

1 in 185,000 live births is the estimated incidence in a general population. Consanguineous parents are more likely than unrelated parents to share a defective gene, which raises the likelihood that their offspring may develop a recessive genetic condition. This “founder effect,” where the prevalence is believed to be as high as 1 in 380, causes the condition to arise more frequently among those in the Mennonite community in the United States. The incidence of MSUD in Ashkenazi Jews is estimated to be 1 in 26,000 live births.

Related Disorders

The following conditions can have symptoms that are similar to MSUD. A differential diagnosis may benefit from comparisons.

The urea cycle, a sequence of biochemical processes in which nitrogen is transformed into urea and eliminated from the body through the urine, is affected by a number of uncommon conditions known as urea cycle disorders. All urea cycle disorders cause excessive ammonia buildup in bodily tissues and blood, which causes symptoms that range in severity (hyperammonemia). Lack of appetite, vomiting, tiredness, seizures, and/or coma are typical symptoms. Hepatomegaly, an abnormal enlargement of the liver, can have potentially fatal consequences. Ornithine transcarbamylase (OTC) deficit, carbamyl phosphate synthetase (CPS) deficiency, argininosuccinate lyase (ASL) deficiency, argininosuccinate synthetase deficiency (citrullinemia), arginase deficiency (argininemia), and N-acetylglutamate synthe (Use the exact illness name as your search phrase in the Rare Disease Database to learn more about these disorders.)

Propionyl CoA carboxylase, one of the enzymes required for breaking down certain amino acids, is one of the enzymes that is deficient in propionyl acidemia, a rare autosomal recessively inherited metabolic condition. In the first few weeks of life, symptoms usually start to show up and can include hypotonia, poor feeding, vomiting, dehydration, and seizures. They may also be accompanied by worsening metabolic acidosis and frequently by hyperammonemia. Coma and other life-threatening consequences are frequent without the proper care. In less severe situations, the issue might not become apparent until later in infancy and might then be accompanied by less concerning signs and symptoms. (In the Rare Disease Database, enter “propionic acidemia” as your search phrase to learn more about this illness.)

People with methylmalonic acidemia (MMA), an uncommon inborn metabolic mistake, have difficulty metabolizing specific proteins and lipids in meals. The signs typically appear within the first few months of life, but they can even go unnoticed until maturity. The manner of presentation is comparable to propionic acidemia. Patients may experience intellectual incapacity, chronic kidney disease, pancreatitis, and eating issues throughout the course of the illness. Different treatments are needed for each kind of MMA since it can result from mutations in a variety of different genes. Methionine, threonine, isoleucine, and valine are the key amino acids that must be restricted in a balanced diet as part of the treatment. some require particular varieties of cobalamin (vitamin B 12). MMAA, MMAB, MMADHC, MCEE, and MUT are the five genes that can develop mutations. All MMAs are autosomal recessive genetic illnesses. (In the Rare Disease Database, enter “methylmalonic acidemia” as your search phrase to learn more about this illness.)

An inborn metabolic mistake known as glycine encephalopathy is characterized by the buildup of significant levels of the amino acid glycine in the blood, particularly in the cerebrospinal fluid (CSF). The breakdown of glycine into smaller molecules causes the metabolic halt. There are four types of this disorder: a mild-episodic newborn form, which is rather prevalent, infantile forms, late-onset forms, and mild-episodic forms. Hypotonia, seizures, unexplained comas, and developmental delays in newborns and young children are typical illness manifestations. Acidosis of the metabolism is not a characteristic. Choose “glycine encephalopathy” as your search phrase in the Rare Disease Database to learn more about this condition.


Newborn screening programs help identify a large number of infants with MSUD. Tandem mass spectrometry, a sophisticated newborn screening test that examines blood samples for more than 40 different illnesses, has helped in the diagnosis of MSUD. As with all inborn mistakes, newborn screening may miss infants with moderate or intermittent versions of the condition since their blood metabolites are completely normal after delivery.

When patients present later, the diagnosis typically occurs during a period of metabolic decompensation, when urine organic acids and plasma amino acids are typically tested and are then grossly aberrant. When combined with the right symptoms, the presence of the maple syrup odor can serve as a sufficient diagnostic tool to start treatment before the patient is transported to an intensive care unit. Urine organic acids and plasma BCAAs are examined for the purpose of initial confirmation. White blood cells or cultivated skin fibroblasts can both execute the BCAA complex activity.

Currently, maternal blood cannot be used to detect pregnancy (looking for the fetal DNA). Either chorionic villus biopsy or amniocentesis are used during the procedure. These tests must be conducted in a laboratory with knowledge of the necessary procedures. It is also possible to confirm the diagnosis with molecular genetic testing for mutations in the BCKDHA, BCKDHB, and DBT genes, which is required for carrier testing for families at risk and prenatal diagnosis for pregnancies at risk.

Standard Therapies

Three main components make up the treatment of classic, intermediate, intermittent, and thiamine-responsive MSUD: 3. Immediate medical care for metabolic crises. 1. Lifelong therapy to maintain a healthy diet. 2. Lifelong maintenance of normal metabolic circumstances, including the body’s BCAA levels. 3.

MSUD patients are need to follow a protein-restricted diet that places restrictions on the quantity of branched-chain amino acids they can consume. Beginning protein restriction as soon as feasible after delivery will help to ensure healthy growth and development. There are artificial (synthetic) formulations that contain all the elements required for healthy growth and development but exclude leucine, isoleucine, and valine. Diet management requires a constant balancing act between trying to keep the patient’s condition and biochemistry within a therapeutic range on the one hand, and trying to supply enough food, protein, and BCAAs to provide for normal growth and development on the other. Limiting the intake of leucine in the diet is very crucial. Essential nutrients include the three amino acids. Depending on their plasma levels, they are each added to the diet separately in tiny doses. A child’s ability to tolerate leucine, isoleucine, and valine relies on the level of remaining enzyme activity. To make sure that their nutrition is sufficient and that their amino acid levels are within the standard ranges, affected youngsters must undergo routine monitoring.

To ascertain whether a patient is thiamine-responsive, some doctors advise a trial of thiamine therapy. However, no patient with MSUD has ever only received thiamine treatment.

Even if affected people completely adhere to the prescribed diet, there is always a chance of a metabolic crisis. Instances of metabolic crisis necessitate prompt medical attention to reduce blood levels of branched-chain amino acids, particularly leucine. Several methods, such as dialysis or a procedure where blood is drawn from the body and then passed through a filter before returning to the body, have been used to lower plasma leucine levels (hemofiltration).

Aggressive treatment for metabolic crises aims to decrease and then reverse the elevated protein catabolism that underlies these episodes. In order to increase calories and decrease protein catabolism (for energy demands), ANY technique may be beneficial. This entails consuming a lot of glucose and supplementing it with a “glucose-insulin drip,” if necessary, as insulin is known to promote endogenous protein synthesis. Another significant calorie source is intravenous fat. All other amino acids must also be supplied in quantities adequate to allow for the creation of new proteins. This is accomplished through the careful use of intra GI drips or, more frequently, parenteral nourishment IV using leucine-free solutions. Branched-chain amino acid may not be present in whole parenteral feeding solutions used in many hospitals. Additionally, insulin may be utilized to promote anabolism, a metabolic process. Amino acids and other substances are created during anabolism to create new proteins and proteins, as well as a wide range of other substances.