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Last updated April 7, 2018

Approved by: Maulik P. Purohit MD, MPH

Hypoglycemia is a condition when the level of glucose or sugar decreases, and is below normal in blood.

What are the other Names for this Condition? (Also known as/Synonyms)

  • Low Blood Glucose
  • Low Blood Sugar

What is Hypoglycemia? (Definition/Background Information)

  • Hypoglycemia is a condition when the level of glucose or sugar decreases, and is below normal in blood. Blood sugar is considered low, when sugar levels are below 70 mg/dL (milligrams per deciliter). The condition can cause weakness, hunger, confusion, blurring of vision, headache, and sweating
  • Hypoglycemia is commonly associated with type-1 and type-2 diabetes. However, the condition can occur in individuals without diabetes as well, and is classified into 2 main subtypes:
    • Fasting Hypoglycemia: It can be associated with starvation, the use of certain medication, alcohol, exercise, and medical conditions, such as hypothyroidism, liver diseases, and tumors
    • Reactive Hypoglycemia: It is often associated with increased circulating levels of insulin in the body (called hyperinsulinism), prediabetes, and surgery associated with intestinal tract. It may also arise after having a meal rich in refined starch or high sugar content
  • Hormone imbalance, liver and kidney malfunction, diabetes medication, starvation, heavy alcohol drinking, and certain tumors can result in Low Blood Glucose levels
  • Infants, adolescents, the elderly, pregnant women, individuals on certain medications, those with autonomous neuropathy, and those eating a poor diet, are at increased risk of being diagnosed with Hypoglycemia
  • The condition is generally diagnosed by checking blood glucose levels, following a physical examination and assessment of symptoms. The immediate recommended treatment is ingesting or administering glucose or sugar products
  • However, if an underlying condition causes a drop-in blood glucose levels, then the healthcare professional may recommend other treatment measures, including addressing the causative factor. If left untreated, Hypoglycemia can cause unconsciousness and seizures; it can lead to death
  • Eating smaller meals several times a day, eating meals regularly, reducing the intake of refined carbohydrates, avoiding alcohol on empty stomach, limiting caffeine intake, and seeking treatment for underlying conditions can help prevent Hypoglycemia
  • The condition is manageable if underlying medical conditions are promptly addressed and recommendations of the healthcare provider followed. It is important to diagnose Hypoglycemia early, to avoid severe complications and ensure a good prognosis

Who gets Hypoglycemia? (Age and Sex Distribution)

  • Hypoglycemia can occur at any age; however, it is mostly observed in infants and elderly adults
  • There is no gender, racial, or ethnic predilection in its occurrence
  • In individuals with diabetes:
    • Individuals with type-1 diabetes are reported to experience Low Blood Sugar levels, several times during a year, with at least one serious event
    • The prevalence of Low Blood Sugar in individuals with type-2 diabetes is significantly less than that for type-1 disease

What are the Risk Factors for Hypoglycemia? (Predisposing Factors)

Risk factors associated with Hypoglycemia include:

  • Diabetes, both type-1 and type-2
  • Age: Infants, adolescents, and older adults have a higher risk
  • Poor diet, starvation
  • Pregnancy (gestation-induced Hypoglycemia)
  • Alcoholism (alcohol-induced Hypoglycemia)
  • Being on certain medications (drug-induced Hypoglycemia)
  • Surgery involving the digestive system

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases one’s chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Hypoglycemia? (Etiology)

Hypoglycemia can be caused by the following factors:

  • Endocrine deficiencies that disrupt normal insulin regulation (endocrine-related Hypoglycemia)
  • Liver failure (hepatic-induced Hypoglycemia)
  • Complication of diabetes treatment
  • Certain medications (drug-induced Hypoglycemia), which may include:
    • Insulin and sulfonylureas combination
    • Salicylates
    • Sulfa drugs
    • Quinine
    • Pentamidine
  • Excessive alcohol intake (alcohol-induced Hypoglycemia)
  • Liver cancer (malignancy-induced Hypoglycemia)
  • Tumors that produce insulin
  • Infection (infection-induced Hypoglycemia)
  • Kidney failure
  • Overtreatment with insulin
  • Pregnancy (gestational-induced Hypoglycemia)
  • Poor diet
  • Surgery in the digestive system

What are the Signs and Symptoms of Hypoglycemia?

The signs and symptoms due to Hypoglycemia varies from individual to individual. Some have mild symptoms, while others may have severe symptoms.

The common signs and symptoms of Hypoglycemia may include:

  • Blurred vision
  • Anxiety, confusion, irritability
  • Fatigue
  • Heart palpitations
  • Headaches
  • Clammy skin, excessive sweating
  • Shakiness/trembling, loss of coordination
  • Numbness around the mouth
  • Dilated pupils
  • Rarely, individuals may experience seizures and loss of consciousness

Note: The majority of early symptoms are caused by epinephrine, a hormone that is released in response to Hypoglycemia. 

How is Hypoglycemia Diagnosed?

For the diagnosis of Hypoglycemia, a healthcare professional may employ the following methods:

  • A thorough physical examination and an assessment of symptoms
  • An evaluation of medical history including history of diabetes
  • A set of criteria, known as Whipple’s triad is used to diagnose the condition. This includes:
    • Symptoms that parallel those of Hypoglycemia
    • Low plasma glucose concentration
    • Symptom relief after glucose level is increased

Note: Individuals with diabetes are able to determine Low Blood Sugar levels themselves, by periodically testing their blood.

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Hypoglycemia?

Some potential complications associated with untreated Hypoglycemia include:

  • Injury due to sudden falls
  • Loss of consciousness
  • Seizure

How is Hypoglycemia Treated?

Hypoglycemia is a potential medical emergency and should be treated promptly. Treatment of Hypoglycemia involves both acute treatment for low sugar levels as well as treatment of underlying medical condition, if any.

  • In order to immediately raise sugar levels, the following methods may be useful:
    • Eating candy
    • Taking glucose tablets
    • If the individual is subconscious, then injecting glucose into a blood vessel
  • Injecting glucagon
  • Drinking apple or grape juice (half cup)
  • Drinking regular soda (half can)
  • Eating raisins (about 2 tablespoons)
  • Ingesting sugar or honey (1 tablespoon)

Treatment of underlying cause may involve:

  • Surgical removal of the tumor causing a drop-in blood glucose levels
  • Dosage adjustment of medication taken to regulate blood glucose levels

How can Hypoglycemia be Prevented?

The following methods may help prevent Hypoglycemia in individuals with and without diabetes:

  • Seeking treatment of underlying medical condition that is causing Hypoglycemia
  • Using correct medication doses to regulate glucose levels
  • Eating meals on time; eating small, more frequent meals, in place of large ones with long gaps between meals
  • Avoiding missed meals
  • Avoiding excessive alcohol consumption, not drinking on an empty stomach
  • Diabetics are advised to keep an accurate log of what is consumed and monitor their glucose levels
  • Not exercising on an empty stomach
  • Limiting caffeine intake
  • Avoiding refined carbohydrates in meals

What is the Prognosis of Hypoglycemia? (Outcomes/Resolutions)

  • The prognosis for Hypoglycemia is good in most individuals, since the symptoms are typically manageable. With appropriate treatment, one can continue their normal daily activities
  • However, the outcome of Hypoglycemia also depends on the underlying cause of the condition
  • Low blood glucose levels, left untreated, can lead to serious complications such as loss of consciousness and seizure, which can even be fatal

Additional and Relevant Useful Information for Hypoglycemia:

The following DoveMed website link is a useful resource for additional information:


What are some Useful Resources for Additional Information?

References and Information Sources used for the Article:

Helpful Peer-Reviewed Medical Articles:

Reviewed and Approved by a member of the DoveMed Editorial Board
First uploaded: April 8, 2017
Last updated: April 7, 2018