Diabetic Coma: DKA & HHS

Kiah Connolly, MD

Diabetes is one of the most common chronic diseases and can lead to many life altering conditions. 

Among the most dangerous complications caused by diabetes are diabetic ketoacidosis (DKA), hyperosmolar hyperglycemic state (HHS) and hypoglycemica. 

What is Diabetes Mellitus? 

Diabetes mellitus is a disease that results when glucose isn’t able to be processed properly in the body because of problems with a hormone called insulin. People with type 1 diabetes aren’t able to produce enough insulin. People with type 2 diabetes are able to produce insulin, it just doesn’t work properly. 

While some people with diabetes can control their disease with exercise and diet alone, many people need medications. Everyone with type 1 diabetes and some people with type 2 diabetes need regular insulin injections to control their disease.

Diabetes can cause many long term complications. Stroke, heart disease, immunosuppression with frequent infections, poor wound healing, nerve damage, and amputations are just a few of the consequences of uncontrolled diabetes. 

While all of these are examples are devastating long term effects of the disease, complications of diabetes can also present suddenly and be deadly.

What is a Diabetic Coma?

Diabetic coma is the term used to describe a change an acute change int the mental state in someone with uncontrolled diabetes. Extreme fluctuations in glucose can cause many problems in the brain including severe confusion, seizures, and a state of unresponsive coma.

A diabetic coma can result from three main causes: 

  1. Hypoglycemia 
  2. Diabetic Ketoacidosis (DKA)
  3. Hyperosmolar Hyperglycemic State (HHS) 

What is Diabetic Ketoacidosis (DKA)?

Diabetic ketoacidosis is a common and potentially deadly complication of diabetes. In DKA there are very high levels of glucose, however there it can’t be used by the cells because there is not enough insulin. 

The body starts to break down fat very quickly for any energy source for the cells. As the liver breaks down this fat, very high levels of a substance called ketones are made. Ketones can be used as an energy source for the body. However when they’re produced too quickly and when there are too many of them, they flood the blood causing it to be too acidic. 

This sequela is often associated with significant dehydration and dangerous electrolyte abnormalities in affected individuals. 

People diagnosed with type 1 diabetes are at a greater risk of DKA.

This is especially true if they miss their insulin doses. However people with advanced type 2 diabetes can also suffer from DKA if their sugars are uncontrolled. 

DKA Diagnosis 

Making the diagnosis of DKA requires blood tests. Sometimes high levels of ketones in the urine are also used to help make the diagnosis of DKA. 

Diagnosing DKA Requires: 

1) Elevated Blood Glucose >250 mg dl

2) Elevated Ketones (betahydroxybutyrate or urine ketones)

3) Acidosis (blood pH <7.3) 

Warning Signs & Symptoms of Diabetic Ketoacidosis

Symptoms classically occur fairly rapidly - usually within 24 hours. 

Although variations occur between individuals common presentations include: 

  • Abdominal Pain 
  • Nausea & Vomiting 
  • Increased Urination
  • Abnormal Breathing (‘Kussmaul Breathing’)
  • Fatigue 
  • Weakness 
  • Confusion

It’s important if you think you or someone you care about has DKA to go to the emergency room. If you have diabetes, discuss with your health care provider about how to recognize symptoms of DKA so you can catch it early. 

What Causes DKA?

There are many potential triggers of DKA. Most often, DKA is caused by people not taking their medications. It's also a common initial presentation for undiagnosed diabetics.

However even the most compliant diabetics can get DKA. Any major stressor on the body of a diabetic can make them susceptible to the disease. 

Common Causes of Diabetic Ketoacidosis

  • Medication Noncompliance 
  • Infections 
  • Major Illness (heart attack or stroke) 
  • Toxins (cocaine)
  • New Diagnosis of Diabetes
  • Idiopathic 

DKA Treatment 

DKA treatment requires improving the acidosis, hyperglycemia, and dehydration by carefully giving the right amount of insulin and fluid and fixing dangerous electrolyte abnormalities (in particular correcting potassium levels). This is done of course while being cautious to prevent any worsening complications, like hypoglycemia. 

Because proper management of DKA is so intensive, it often requires hospital admission to the intensive care unit (ICU) for extremely close monitoring and treatment. 

DKA Prevention

The best ways to prevent diabetic ketoacidosis includes: 

  1. Frequent blood glucose checks
  2. Well controlled diet 
  3. Regulated exercise 
  4. Consistent medication 

Unfortunately for type 1 diabetics, this may still not be enough. Infections and other stressors on the body can still trigger DKA even in the most compliant individuals. 

The next best thing to helping manage DKA is catching it early. You can do this yourself by checking your urine ketone levels if your glucose is very high or if you’re feeling any symptoms of DKA. 

Diabetics with positive ketones should always be evaluated by a doctor to ensure they are not in diabetic ketoacidosis. 

Ketoacidosis vs. Ketosis

Just to avoid any confusion: ketoacidosis is not the same as ketosis. 

Ketosis is a metabolic state in which the body begins using other forms of energy called ketone bodies. It occurs gradually and can be the result of starvation or eating very few carbohydrates.

It is a normal physiologic process in these environments. It is not dangerous, does not involve a significant acidosis and is the goal in the popular ketogenic diet. Ketone level goals for dieting are usually less than 3. 

Ketoacidosis is a dangerous condition that involves both the presence of ketone bodies and acidosis in DKA described above. These levels of ketone bodies can be significantly higher often greater than 15. 

Hyperosmolar Hyperglycemic State (HHS) 

HHS is another dangerous condition that can occur when the glucose levels become extremely high and share many similarities to DKA.

DKA vs. HHS chart (sugar levels, ketoacidosis, slower onset in HHS) 

HHS Symptoms 

The symptoms of HHS may develop more slowly than DKA. It may start off with non-specific fatigue and generalized weakness, and over a few days progress to more significant symptoms including coma (1).

Common HHS Presentations

  • Frequent Urination (polyuria) 
  • Extreme Thirst (polydypsia) 
  • Fatigue 
  • Weakness
  • Confusion 
  • Coma (25-50%)

HHS Diagnosis

The main difference between DKA and HHS is that the body isn’t too acidic in HHS.  The glucose levels are usually much higher in HHS than DKA, often exceeding 1000 mg/dL. 

Diagnosing HHS Requires: 

  • Glucose > 600 mg/dl 
  • Osmolality > 320 mOsm/kg 
  • pH > 7.3

HHS Treatment 

The treatment for HHS is similar to that of DKA, involving careful insulin administration and hydration as well as careful monitoring, often in the intensive care unit (ICU) of the hospital. 


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