What is hypoglycemia?
Hypoglycemia is a condition characterized by an abnormally low level of blood sugar (glucose). Glucose is the main source of energy for the body’s cells, and without sufficient glucose, the body cannot function properly.
The normal range for blood sugar is around 70 to 100 mg/dL when fasting, and up to 140 mg/dL after eating. Hypoglycemia is defined as a blood sugar level below 70 mg/dL.
Causes of hypoglycemia
There are several potential causes of hypoglycemia, including:
– Medications – Such as insulin or oral diabetes medications, which can cause blood sugar to drop too low if not properly balanced with food intake. This is the most common cause of hypoglycemia.
– Critical illness – Severe infections, kidney or liver disease can cause hypoglycemia.
– Hormonal deficiencies – Not having enough cortisol or growth hormone can interfere with blood sugar regulation.
– Tumors – Tumors in the pancreas that secrete excess insulin can cause hypoglycemia.
– Prolonged fasting – Not eating for extended periods of time can lead to low blood sugar.
– Alcohol use – Drinking excess alcohol, especially on an empty stomach, can prevent the liver from releasing enough glucose.
– Gastric surgery – Operations like gastric bypass surgery can change how food is digested and absorbed, leading to hypoglycemia.
– Certain medications – Drugs like quinine and pentamidine can cause low blood sugar.
– Genetic disorders – Some enzyme deficiencies passed down genetically can disrupt normal glucose metabolism.
Signs and symptoms
The signs and symptoms of hypoglycemia often come on quickly and can vary from person to person. Common symptoms include:
– Anxiety, irritability, confusion
– Shakiness, sweating, chills
– Hunger, nausea
– Blurred vision
– Fast heartbeat
– Tingling or numbness in the lips or tongue
– Drowsiness, weakness, fatigue
– Difficulty concentrating, headaches
– Seizures
In severe cases, hypoglycemia can lead to loss of consciousness or even death if untreated. Infants and young children may experience floppy muscles and twitching during hypoglycemic episodes.
The onset of symptoms is related to how low the blood sugar level falls. Mild to moderate hypoglycemia can cause variations in mood and energy levels. But severely low blood glucose levels can result in cognitive impairment, seizures, coma, and other serious complications.
What happens when hypoglycemia goes untreated?
When hypoglycemia is not treated promptly and blood glucose remains low, a number of detrimental effects on the body can occur.
Brain effects
The brain relies on glucose as its main source of fuel. When levels fall too low, brain function becomes impaired. This manifests as cognitive dysfunction, confusion, and loss of consciousness in hypoglycemia.
Prolonged, severe hypoglycemia can result in permanent brain damage due to the death of neurons and other cells that cannot survive without glucose. Areas of the brain that are especially vulnerable include the cerebral cortex, hippocampus, and basal ganglia.
The effects on the brain can include:
– Impaired memory and cognitive skills
– Reduced motor coordination and reflexes
– Abnormal behavior
– Personality changes
– Coma or seizure activity
Cardiovascular effects
Hypoglycemia triggers the release of epinephrine and norepinephrine, hormones that prepare the body for the “fight or flight” response. This causes an increase in heart rate, blood pressure, and cardiac workload.
When severe hypoglycemia is prolonged, it can result in:
– Abnormal heart rhythms (arrhythmias)
– Heart damage due to insufficient oxygen delivery
– Shock
There is also an increased risk of thrombosis, or blood clot formation, during hypoglycemic episodes. Clots that travel to the heart or lungs can lead to myocardial infarction or pulmonary embolism.
Death
Without treatment, severe hypoglycemia can ultimately result in death. Very low blood glucose starves the cells of the body from their main energy supply. Prolonged, severe hypoglycemia can cause widespread organ and tissue damage.
The specific cause of death is often related to:
– Brain damage or brain death, due to neuronal cell death
– Heart failure, from arrhythmias or oxygen deprivation
– Respiratory failure, as respiration centers in the brain stem stop functioning
– Kidney failure, from lack of oxygenated blood flow
Death can occur during sleep, or quickly due to accidents or injuries sustained during a hypoglycemic coma or seizure. The risk of death depends on the severity and duration of untreated hypoglycemia.
Diagnosing hypoglycemia
Hypoglycemia is diagnosed by checking blood sugar levels. A fasting blood glucose test or random blood glucose test can confirm abnormally low blood sugar.
Levels below 70 mg/dL indicate hypoglycemia. Additional testing helps determine the cause, such as measurements of:
– Insulin levels
– C-peptide levels
– Antibodies related to autoimmune hypoglycemia
– Growth hormone or cortisol levels if hormone deficiencies are suspected
Home blood glucose testing
Checking blood sugar at home allows people at risk of hypoglycemia to monitor their levels. This can help detect and treat low blood sugar episodes promptly.
Patients with diabetes routinely perform self-monitoring of blood glucose (SMBG) using at-home fingerstick devices. This allows tracking of fluctuations in glucose levels throughout the day to prevent hypoglycemia.
Treating hypoglycemia
Treating hypoglycemic episodes quickly can prevent severe complications and death. Treatment aims to raise blood glucose levels back to normal as fast as possible.
Mild to moderate hypoglycemia
When blood sugar is under 70 mg/dL or hypoglycemia symptoms are present, consuming fast-acting carbohydrates can treat mild to moderate lows.
Examples of 15 gram portions of fast-acting carbohydrates include:
– 1/3 cup juice or regular soda
– 3-4 glucose tablets
– 1 tablespoon honey or sugar
– 4-6 hard candies
– 1 small fruit (banana)
These simple sugars are absorbed rapidly to boost blood glucose. Retesting blood sugar after 15 minutes determines if additional carbohydrates are needed.
Severe hypoglycemia
For blood sugar under 50 mg/dL or when hypoglycemia causes unconsciousness, seizure, or inability to swallow, an injection of glucagon is given. Glucagon triggers the release of glucose from glycogen stored in the liver to quickly raise blood sugar.
Caregivers or family members should be trained on when and how to administer glucagon for severe hypoglycemia. After glucagon, eating fast-acting carbohydrates helps restore normal glucose levels.
An IV solution of glucose may be given in a hospital setting for severe hypoglycemia causing coma or confusion.
Preventing future episodes
Once the hypoglycemic episode is treated, steps should be taken to prevent additional occurrences.
For people with diabetes, this may involve adjusting medications, changing dietary habits, more frequent blood sugar testing, or using a continuous glucose monitor. Hypoglycemia unawareness can be improved with more stringent glucose control.
Identifying and addressing the underlying cause of hypoglycemia is also important. Treatments may include:
– Changing medications known to cause low blood sugar
– Providing treatment for hormonal deficiencies or diseases causing hypoglycemia
– Removing benign insulin-secreting tumors
– Eating small, frequent meals to maintain glucose levels
With proper emergency treatment and follow-up care, severe complications and death from hypoglycemia can be prevented. Awareness of the dangers of untreated hypoglycemia is imperative.
Conclusion
Hypoglycemia occurs when blood sugar falls to dangerously low levels. Without treatment, it can lead to significant effects on the brain, cardiovascular system, and other organs that rely on glucose for normal function.
Severe, prolonged hypoglycemia can result in permanent brain damage, heart problems, kidney failure, respiratory failure, coma, and death. Checking blood glucose levels and promptly treating lows with carbohydrates or glucagon can prevent these serious outcomes.
Controlling underlying medical conditions and adjusting medications or dietary regimens helps avoid recurrent hypoglycemia. Increasing awareness and monitoring of blood sugar levels is key for people at risk of developing low blood glucose. Prompt detection and management of hypoglycemia is life-saving.