TL;DR:
Blood sugar can become dangerously high or dangerously low, and both situations can quickly become life-threatening if left untreated. Learn how to recognize the symptoms of hypoglycemia and hyperglycemia, when to seek emergency medical care, and how serious complications like hypoglycemic shock, diabetic ketoacidosis (DKA), and hyperosmolar hyperglycemic state (HHS) develop. Knowing the warning signs could help save a life.
Millions of Americans experience blood sugar problems that sometimes make their levels too high or too low. Mild changes in blood sugar are common and usually easy to manage, but serious problems can quickly become medical emergencies.
Recognizing the warning signs can help prevent serious complications, including seizures, coma, permanent organ damage, and death. Understanding blood sugar emergencies is an essential first-aid skill, whether you have a blood sugar condition, care for someone who does, or want to be prepared for emergencies.
What Is Blood Sugar?
Blood sugar, in medical terms, is the amount of glucose in the blood. Even though there may be other types of sugar, such as fructose, present, only the amount of glucose is included. Glucose is the body’s main energy source. It comes from food and is regulated by hormones, primarily insulin.
Since glucose is required for energy, it is essential that a sufficient amount is readily available in the blood. However, too much blood sugar (hyperglycemia) or too little blood sugar (hypoglycemia) can cause medical problems ranging from minor to life-threatening emergencies.
What Is Low Blood Sugar (Hypoglycemia)?
Hypoglycemia generally refers to a blood glucose level below 70 mg/dL. It commonly affects people with diabetes who take insulin or certain diabetes medications, but it can also occur in people without diabetes under certain circumstances.
Common causes include:
- Taking too much insulin
- Skipping meals
- Exercising more than usual
- Drinking alcohol without eating
- Certain medications
- Hormonal disorders or severe illness
Signs and Symptoms of Low Blood Sugar
Early symptoms often develop quickly and may include:
- Headache
- Blurred vision
- Dizziness
- Weakness
- Shaking or trembling
- Sweating
- Hunger
- Anxiety or nervousness
- Fast heartbeat
As blood sugar continues to fall, symptoms become more serious:
- Confusion
- Difficulty speaking
- Poor coordination
- Personality changes
- Extreme drowsiness
- Loss of consciousness
- Seizures
How to Treat Mild Low Blood Sugar
If the person is conscious and able to swallow safely:
Use the 15-15 Rule:
- Eat or drink 15 grams of fast-acting carbohydrates, such as:
- Glucose tablets
- Glucose gel
- Fruit juice (4 oz orange juice)
- Soda (full sugar)
- Hard candy
- Wait 15 minutes.
- Recheck blood sugar.
- Repeat if still below 70 mg/dL.
Once blood sugar improves, eat a meal or snack containing protein and carbohydrates if the next meal is more than an hour away.
When Low Blood Sugar Becomes an Emergency
Call 911 immediately if someone with suspected low blood sugar:
- Becomes unconscious
- Has a seizure
- Cannot swallow
- Is confused and unable to safely eat or drink
- Does not improve after treatment
Do not attempt to force food or drink into someone who is unconscious or unable to swallow.
If you are susceptible to low blood sugar, your doctor may prescribe glucagon, an emergency medication that raises blood sugar. Glucagon is available as a nasal spray or injector.
What Is Hypoglycemic Shock?
Hypoglycemic shock is caused by severe hypoglycemia in which the brain no longer receives enough glucose to function properly.
Because the brain is dependent on glucose for energy, prolonged hypoglycemia can cause permanent brain injury.
Symptoms include:
- Unresponsiveness
- Seizures
- Extremely low blood pressure
- Coma
- Cardiac arrest
This is a life-threatening medical emergency.
Treatment requires:
- Immediate EMS activation
- Glucagon if available
- Intravenous glucose administered by healthcare professionals
What Is High Blood Sugar (Hyperglycemia)?
Hyperglycemia occurs when blood glucose rises above normal, often above 180 mg/dL after meals, although emergency complications usually occur at much higher levels.
Common causes include:
- Untreated diabetes
- Missed insulin doses
- Illness or infection
- Stress
- Certain medications such as steroids
- Eating more carbohydrates than usual
- Undiagnosed diabetes
Signs and Symptoms of High Blood Sugar
Early symptoms include:
- Increased thirst
- Frequent urination
- Dry mouth
- Fatigue
- Blurred vision
- Headache
As blood sugar continues rising:
- Increasing weakness
- Weight loss
- Nausea
- Vomiting
- Abdominal pain
- Dry skin
- Dehydration
- Difficulty concentrating
When High Blood Sugar Becomes an Emergency
Extremely high blood sugar can lead to two dangerous complications:
- Diabetic Ketoacidosis (DKA)
- Hyperosmolar Hyperglycemic State (HHS)
Both require emergency medical treatment.
What Is Diabetic Ketoacidosis (DKA)?
Diabetic ketoacidosis (DKA) is commonly caused by severe lack of insulin. Without insulin, the body can not use blood sugar to produce energy. Instead, the body begins breaking down fat, which produces acids called ketones. As ketones build up, the blood becomes dangerously acidic.
DKA most commonly occurs in people with Type 1 diabetes, although it can also occur in Type 2 diabetes.
Symptoms of DKA
- Blood sugar often above 250 mg/dL
- Excessive thirst
- Frequent urination
- Nausea and vomiting
- Abdominal pain
- Fruity-smelling breath
- Rapid, deep breathing (Kussmaul respirations)
- Confusion
- Severe dehydration
Without treatment, DKA can lead to:
- Coma
- Organ failure
- Death
Treatment includes:
- IV fluids
- Insulin
- Electrolyte replacement
What Is Hyperosmolar Hyperglycemic State (HHS)?
Hyperosmolar Hyperglycemic State (HHS) is another life-threatening complication that generally affects people with Type 2 diabetes, especially older adults.
Unlike DKA, ketones are usually minimal or absent. Instead, blood sugar becomes extremely elevated, often exceeding 600 mg/dL, causing profound dehydration.
Symptoms of HHS
- Extreme thirst
- Very frequent urination
- Dry mouth
- Warm, dry skin
- Fever
- Weakness
- Confusion
- Hallucinations
- Vision changes
- Seizures
- Coma
HHS develops more gradually than DKA but carries a high mortality rate if untreated.
Emergency treatment includes:
- Aggressive IV fluids
- Insulin
- Electrolyte replacement
When Should You Call 911?
Seek emergency medical care immediately if someone:
- Becomes unconscious
- Has a seizure
- Cannot be awakened
- Has severe confusion
- Has trouble breathing
- Vomiting
- Severe dehydration
- Cannot keep fluids down
- Has symptoms of DKA or HHS
- Has severe low blood sugar that doesn’t respond to treatment
Symptoms of blood sugar emergencies can be similar to alcohol intoxication. We have treated several people who were arrested for DUI but were actually suffering a diabeti
Tests That Check for Blood Sugar Problems
Several tests help diagnose or monitor diabetes and blood sugar disorders.
Fingerstick Blood Glucose Test
A drop of blood from the fingertip provides an immediate blood sugar reading using a glucose meter.
Commonly used for:
- Daily diabetes management
- Emergency evaluation
- Confirming suspected hypoglycemia
Continuous Glucose Monitor (CGM)
A small sensor worn under the skin continuously measures glucose throughout the day and night.
CGMs can:
- Alert users to dangerous highs and lows
- Identify trends
- Improve diabetes management
Hemoglobin A1C Test
The A1C test shows the percentage of red blood cells with sugar attached to them. This helps measure average blood sugar over the previous two to three months.
Typical interpretation:
- Below 5.7%: Normal
- 5.7%–6.4%: Prediabetes
- 6.5% or higher: Diabetes
Fasting Blood Glucose Test
Measures blood sugar after fasting for at least eight hours.
Used to:
- Screen for diabetes
- Diagnose diabetes
- Monitor treatment effectiveness
Oral Glucose Tolerance Test (OGTT)
The Oral Glucose Tolerance Test, commonly called the glucose tolerance test, measures how well the body processes sugar.
During the test:
- A fasting blood sample is obtained.
- The patient drinks a sugary glucose solution.
- Blood sugar is measured at scheduled intervals over approximately two hours.
The glucose tolerance test is commonly used to:
- Diagnose prediabetes
- Diagnose Type 2 diabetes
- Diagnose gestational diabetes during pregnancy
Can Blood Sugar Emergencies Be Prevented?
Many emergencies can be prevented through careful diabetes management.
Helpful strategies include:
- Take medications exactly as prescribed.
- Monitor blood sugar regularly.
- Eat consistent, well-balanced meals.
- Carry fast-acting glucose if you’re at risk for hypoglycemia.
- Stay hydrated.
- Never ignore persistent high blood sugar.
- Follow your healthcare provider’s sick-day plan when you’re ill.
- Wear a medical alert bracelet if you have diabetes.
- Teach family members how to recognize blood sugar emergencies and how to use glucagon if prescribed.
Final Thoughts
Both high and low blood sugar can progress from mild symptoms to life-threatening emergencies surprisingly quickly. Low blood sugar can lead to hypoglycemic shock, while uncontrolled high blood sugar may result in diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS). Knowing the symptoms, monitoring blood sugar regularly, and seeking emergency medical care when necessary can prevent serious complications.
Whether you have diabetes or care for someone who does, understanding these emergencies is one of the most important steps you can take to protect your health and possibly save a life.