What level of blood sugar is considered dangerous?


High Blood Sugar Symptoms: Causes, Signs, and Taking Control

Blood sugar, or glucose is essential as it serves as a major source of energy for the human body. But with any good thing in life, moderation is the key. The human body is remarkable in ensuring every little component is kept in the most optimal range. This is called homeostasis. In fact, a whole mechanism involving organs and hormones are in charge to regulate blood sugar in order to avoid extreme falling or rising into dangerous levels. In other words, it is dangerous when blood sugar level is too low or too high.

The normal blood sugar level for adults is between 70 to 100 mg/dL during fasting, and between 70 to 150 mg/dL after a meal. While it may not be symptomatic, anything lower than that is considered hypoglycemia. Whereas individuals with persistently high blood sugar levels may have diabetes, diabetic ketoacidosis (DKA) or hyperosmolar hyperglycemic state (HHS). Treatment aims differ either to raise or reduce blood sugar level back to the optimal state.

Hypoglycemia is when blood sugar falls below abnormal levels (less than 70 mg/dL) and is a common occurrence in patients treated with diabetes. For those without diabetes, it may be triggered by certain medications, excessive alcohol consumption, or diseases that affect the kidney, liver or pancreas. Weight loss surgery and anorexia nervosa may also result in hypoglycemia. Regardless of the cause, it can be easily diagnosed by a simple blood glucose test. A person presented with mild symptoms like shaking, sweating and feeling hungry, and has blood sugar level less than 70 mg/dL can be sure of having hypoglycemia. However, the presence of hypoglycemic disorder in non-diabetic individuals should not be inferred solely based on low blood sugar level, unless the blood sugar level is severely low (less than 40 mg/dL). At such state, the person may experience severe symptoms of significant hypoglycemia, such as:

  • Headache, dizziness or blurry vision
  • Feeling weak and troubled walking
  • Unable to think clearly or confused
  • Fainting or passed out

Clinically significant hypoglycemia that is untreated can be dangerous as it can lead to accidents, injury, coma and even death. Furthermore, studies have found that severe hypoglycemia is associated with increased risk of dementia, fractures and heart attacks. Treatment is as simple as replenishing the body with sugar.

On the other end of the spectrum, extremely high blood sugar levels can lead to life-threatening conditions called diabetic ketoacidosis (DKA) and hyperosmolar hyperglycemic state (HHS). These are also two of the most serious complications of diabetes. The difference between them is that DKA has hyperglycemia (high sugar) and ketoacidosis, while HHS only has severe hyperglycemia and no ketoacidosis. The blood glucose level in DKA is often around 350 to 500 mg/dL as compared to HHS which frequently exceeds 1000 mg/dL (keeping in mind that the normal upper level is only 150 mg/dL after a meal!). In addition, high concentrations of ketone bodies are present in DKA which can be detected in the blood and urine. Dangerously build-up of ketone bodies can lead to coma and potentially death.

As both DKA and HHS have the same characteristic of hyperglycemia, they present similar symptoms, including increased thirst (polydipsia), frequent urination (polyuria), extreme hunger that leads to more eating (polyphagia) and unexplained weight loss. As the conditions worsen, the patient suffers from neurological disturbances like lethargy, irritability, weakness in arms and legs or seizure. This may progress to coma. Besides, DKA also presents with abdominal pain, nausea and vomiting. Patients with either DKA or HHS are severely dehydrated, which is evident by dry lips and armpits, fast heart rate, rapid breathing and low blood pressure. Additionally, patients with DKA may give out a fruity odour due to acetone which has a similar scent as nail polish remover. The principle of treatment is reducing the extremely high blood sugar levels by insulin and replenishing the body with fluid and electrolytes.