Hypoketotic hypoglycemia occurs when a person has low blood sugar levels due to their inability to break down fats efficiently for energy. It typically has links to fatty acid oxidation disorders.

Fatty acid oxidation disorders are a type of inherited metabolic condition that negatively affects the body’s ability to break down fats for energy.

Typically, when blood sugar levels dip, the body will switch to using fats. However, a person with a fatty acid oxidation disorder cannot effectively process the fat for energy. This leads to both low blood sugar levels and low energy.

This article reviews what hypoketotic hypoglycemia is, the possible causes, symptoms, treatments, and more.

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Hypoketotic hypoglycemia occurs when blood sugar levels and energy are low. It often occurs as a result of rare inherited metabolic disorders known as fatty acid oxidation disorders.

Usually, the body will start to break down fats for energy when blood glucose (sugar) levels are low. A person with a fatty acid oxidation disorder cannot efficiently break down fats for energy. This leaves them with both low blood glucose levels and low energy.

Fatty acid oxidation disorders and similar disorders can appear at any age but often present during infancy, early childhood, and adolescence.

Hypoketotic hypoglycemia typically occurs due to fatty acid oxidation disorders. There are several different types of this disorder. The most common is medium-chain acyl-CoA dehydrogenase deficiency.

Other types of fatty acid oxidation disorders include:

  • very long-chain acyl-CoA dehydrogenase deficiency
  • long-chain 3-hydroxy acyl-CoA dehydrogenase deficiency
  • trifunctional protein deficiency

Long-chain fatty acids require a substance known as carnitine to carry them across the mitochondrial inner membrane for use in producing energy. Carnitine transport disorders affect the ability to transport fatty acids effectively, which can also lead to hypoketotic hypoglycemia and other symptoms.

Some examples of carnitine transport disorders include:

  • carnitine palmitoyltransferase type 1 deficiency
  • carnitine-acylcarnitine translocase deficiency
  • carnitine palmitoyltransferase type 2 deficiency
  • carnitine transporter deficiency

Learn more about carnitine.

Hypoketotic hypoglycemia can cause symptoms similar to low blood glucose levels. These include:

Without treatment, it can lead to more severe symptoms that may include:

Diagnosis may begin when a parent or guardian consults a doctor due to a child exhibiting signs of low blood sugar levels. A doctor may begin with a physical examination along with a review of personal and family medical history.

To diagnose a fatty acid disorder or carnitine transport disorder, a doctor may need to run various tests to determine the underlying causes. Tests can include:

The doctor will be able to explain the tests that they order and answer any questions.

Treatments can vary depending on the exact underlying disorder causing hypoketotic hypoglycemia. Experts note that the four parts of treatment for any fatty acid oxidation disorder should include:

  • ongoing nutritional management, which often involves working with a metabolic dietician or doctor to help manage a person’s diet
  • aggressive treatment during illness, which may involve providing additional carbohydrates and sources of energy when the individual is under metabolic stress
  • avoiding fasting, as this does not allow blood sugar levels to dip through regular feeding of infants or children

Another possible treatment is supplementing carnitine. However, this is somewhat controversial and may only help in secondary cases of carnitine disorders.

The doctor will be able to advise on which treatments they recommend and what the treatments involve.

An individual should contact a doctor if they have concerns about the symptoms of hypoketotic hypoglycemia or fatty acid oxidation disorders.

A parent or guardian should watch for signs of possible hypoglycemia, such as increased irritability, fast heartbeat, and shaking. A doctor can help determine the underlying cause of the symptoms and provide treatment as necessary.

A pregnant individual may receive screening before the birth of the fetus. This may indicate the presence of a fatty acid disorder that can lead to hypoketotic hypoglycemia. If this is the case, the doctor will be able to advise on what action to take and what symptoms to monitor for after the birth.

Hypoketotic hypoglycemia occurs when blood glucose and ketones are low. It typically occurs because the body cannot process fats properly when sugar is not present or low.

It is often a symptom of fatty acid oxidation disorders. Treatment typically involves keeping a person from fasting and providing adequate amounts of carbohydrates during acute infections.

It is best for a person to contact a doctor if they have concerns about hypoketotic hypoglycemia or fatty acid oxidation disorders. Healthcare professionals may order tests to confirm the diagnosis and advise on suitable treatments.