Hypoglycaemia Symptoms: Early Signs, Causes & Treatment

Quick Glance: Common Hypoglycaemia Symptoms

Hypoglycaemia often appears with a series of symptoms that arise quickly as a result of the lowering of blood glucose levels. Early symptoms may include:

Shaking or trembling
Sweating or clammy skin
Fast heartbeat
Sudden hunger
Dizziness
Tingling around the lips
Irritability
Pale skin

Hypoglycaemia Symptoms That Should Not Be Ignored

Some symptoms indicate that blood glucose has fallen to a critically low level and the brain is no longer receiving adequate glucose to function properly. Some of the hypoglycaemia symptoms and what they indicate are given below:

Symptom	What It May Indicate
Confusion or slurred speech	The brain is not receiving enough glucose and urgent treatment may be needed.
Blurred or double vision	Blood sugar has fallen to a dangerously low level.
Extreme weakness	Severe hypoglycaemia affecting muscle function.
Seizures	Medical emergency requiring immediate treatment.
Unconsciousness	Severe hypoglycaemia that may lead to coma if untreated.
Night sweats with morning headache	Possible nocturnal hypoglycaemia.
Repeated episodes without diabetes medication	Underlying medical condition requiring evaluation.

Why Do Hypoglycaemia Symptoms Occur?

The symptoms of hypoglycaemia result from two different reactions that take place physiologically in the body due to a reduction in blood sugar levels. They are:

Hormonal Response When blood glucose begins to fall, the pancreas reduces the release of insulin and increases the release of glucagon. Glucagon signals the liver to release stored glucose into the bloodstream. At the same time, the adrenal glands release adrenaline (epinephrine), which triggers early warning symptoms such as shaking, sweating, a fast heartbeat, hunger and anxiety. These symptoms encourage the person to consume fast-acting carbohydrates before blood sugar drops further.
Reduced Glucose Supply to the Brain If blood glucose continues to fall, the brain does not receive enough glucose to function normally. This can lead to difficulty concentrating, confusion, blurred vision, slurred speech, dizziness and unusual behaviour. In severe cases, prolonged glucose deprivation can cause seizures, loss of consciousness or a hypoglycaemic coma, making immediate medical treatment essential.Symptoms and their severity can vary from person to person depending on the cause of hypoglycaemia, how quickly blood glucose falls and whether the individual has experienced repeated episodes of low blood sugar.

Hypoglycaemia Symptoms That Require Immediate Medical Attention

Hypoglycaemia can worsen suddenly. In the following scenarios, urgent measures must be taken:

Confusion, aggression, or inability to speak clearly
Severe seizure episodes
Inability to be woken up or lack of responsiveness
A blood glucose level lower than 54 mg/dL that does not increase despite consuming rapid-absorbing sugar

Symptoms of Hypoglycaemia Based on Type

Different types of hypoglycaemia appear with different symptoms. The table below highlights the specific types and their common symptoms:

Type of Hypoglycaemia	Common Symptoms
Diabetic hypoglycaemia	Trembling, sweating, hunger, confusion
Reactive hypoglycaemia	Shaking, sweating and hunger occurring 2-4 hours after meals
Fasting hypoglycaemia	Weakness, dizziness and confusion after prolonged fasting
Nocturnal hypoglycaemia	Night sweats, nightmares, morning headache
Hypoglycaemia unawareness	Very low blood sugar with few or no warning symptoms

Symptoms of Hypoglycaemia-Specific Conditions

Different clinical presentations of hypoglycaemia may cause different symptoms. Though the common signs of low blood sugar remain similar, the symptoms often depend on the underlying cause.

Symptoms of some hypoglycaemia-specific conditions are given in the table below:

Type of Hypoglycaemia	Common Symptoms
Reactive (Postprandial) Hypoglycaemia	Shaking, sweating, hunger, dizziness, weakness and anxiety occurring 2 to 4 hours after a meal, particularly one high in carbohydrates.
Drug-Induced Hypoglycaemia	Sweating, trembling, palpitations, confusion, blurred vision and drowsiness, usually after taking insulin or certain diabetes medicines such as sulfonylureas.
Exercise-Induced Hypoglycaemia	Fatigue, shakiness, excessive sweating, dizziness, hunger and reduced exercise performance during or after prolonged or intense physical activity.
Alcohol-Related Hypoglycaemia	Sweating, confusion, slurred speech, dizziness, weakness and loss of consciousness, particularly after drinking alcohol on an empty stomach or after prolonged alcohol consumption.

Symptoms of Hypoglycaemia in Men

Most symptoms of hypoglycaemia are the same in men and women. However, men taking insulin who perform prolonged physical activity or consume alcohol may have a higher risk of exercise or alcohol-related hypoglycaemia. Some common hypoglycaemia symptoms in men are:

Shaking, sweating and dizziness during or after prolonged or intense physical activity.
Sudden hunger, weakness or fatigue after strenuous exercise.
Delayed hypoglycaemia several hours after consuming alcohol, particularly on an empty stomach.
Confusion, poor coordination or slurred speech may occurr if blood glucose falls significantly.

Symptoms of Hypoglycaemia in Children

Hypoglycaemia in children demands special care since young children may fail to recognise or describe the symptoms of hypoglycaemia. Some common symptoms of hypoglycaemia in children are:

Irritability or unusual crying.
Difficulty feeding in infants.
Shakiness or trembling.
Pale skin.
Drowsiness or unusual tiredness.
Difficulty concentrating or confusion in older children.
Poor coordination or unsteady movements.

Can You Have Hypoglycaemia Without Symptoms?

Yes, hypoglycaemia unawareness is common in individuals who suffer from repeated episodes of hypoglycaemia. Each of the episodes leads to the blunting of the adrenaline effect, thereby resulting in the loss of warning symptoms of hypoglycaemia. This increases the risk of serious or fatal hypoglycaemia since there is no way of knowing that the sugar levels are getting dangerously low.

A continuous glucose monitoring device (CGM), increasingly popular in India, can be useful in detecting hypoglycaemia among unaware individuals.

When Can Hypoglycaemia Symptoms Become Life-Threatening?

Hypoglycaemia symptoms that can be life-threatening include:

Seizures
Loss of consciousness
Hypoglycaemic coma

How are Hypoglycaemia Symptoms Diagnosed?

Hypoglycaemia is diagnosed by measuring blood glucose when symptoms are present. Doctors generally recommend the following tests to diagnose hypoglycaemia, based on the symptoms and the medical history of a patient. They also consider whether a patient has diabetes before recommending the tests.

The following table lists the diagnostic tests used to diagnose hypoglycaemia:

Diagnostic Test or Assessment	Purpose
Laboratory Plasma Glucose Test	Confirms hypoglycaemia by accurately measuring blood glucose levels and is the reference standard for diagnosis.
Fingerstick Blood Glucose Test	Provides an immediate blood glucose reading during symptoms to help identify low blood sugar.
Continuous Glucose Monitoring (CGM)	Tracks glucose levels throughout the day and night to detect recurrent, nocturnal or asymptomatic hypoglycaemia.
72-Hour Supervised Fasting Test	Used in selected cases of recurrent hypoglycaemia without diabetes to investigate causes such as insulinoma or other endocrine disorders.
Mixed Meal Tolerance Test	Helps diagnose reactive (postprandial) hypoglycaemia by assessing blood glucose levels after a standardised meal.
HbA1c Test	Measures average blood glucose levels over the previous 2 to 3 months. It does not diagnose hypoglycaemia but helps assess overall glucose control in people with diabetes.

FAQs

Q1. What are the early signs of hypoglycaemia?

Ans: Early signs of hypoglycaemia include shaking, sweating, palpitations, pale skin, dizziness and intense hunger. These symptoms usually appear when blood glucose falls to around 70 mg/dL and signal the need for immediate carbohydrate intake.
Q2. At what blood glucose level is hypoglycaemia diagnosed?

Ans: For most people, hypoglycaemia is defined as a blood glucose level below 70 mg/dL (3.9 mmol/L). However, people with long-standing diabetes may experience symptoms at higher glucose levels.
Q3. How are hypoglycaemia symptoms different from hyperglycaemia symptoms?

Ans: Hypoglycaemia usually causes sudden symptoms such as shaking, sweating, palpitations and confusion. Hyperglycaemia typically develops more gradually and commonly causes excessive thirst, frequent urination and tiredness.
Q4. When should someone seek emergency help for hypoglycaemia?

Ans: Seek emergency medical care if a person with hypoglycaemia becomes unconscious, has seizures or is unable to swallow. If available, a trained caregiver should administer glucagon while waiting for medical assistance.
Q5. Can hypoglycaemia occur in people without diabetes?

Ans: Yes. Hypoglycaemia can occur in people without diabetes due to prolonged fasting, excessive alcohol intake, certain medicines, liver or adrenal disorders, reactive hypoglycaemia or, rarely, an insulin-producing tumour.
Q6. What is hypoglycaemia unawareness?

Ans: Hypoglycaemia unawareness is a condition in which blood sugar falls to dangerously low levels without the usual warning symptoms. It often develops after repeated episodes of hypoglycaemia.
Q7. Can hypoglycaemia lead to complications?

Ans: Yes. Frequent or severe hypoglycaemia may damage brain cells and can lead to memory problems, impaired thinking, nervous system damage and other long-term complications if left untreated.
Q8. How can nocturnal hypoglycaemia be identified?

Ans: Nocturnal hypoglycaemia may cause night sweats, nightmares, disturbed sleep, morning headaches, confusion on waking or unusual daytime sleepiness. Blood glucose monitoring or continuous glucose monitoring (CGM) can help detect these episodes.

References
- https://www.ncbi.nlm.nih.gov/books/NBK534841/
- https://www.ninds.nih.gov/health-information/disorders/Hypoglycaemia
- https://pmc.ncbi.nlm.nih.gov/articles/PMC9441498/