Ketoacidosis is a dangerous metabolic emergency where the blood becomes acidic due to a massive buildup of ketones, which are acids your body produces when it burns fat for fuel instead of sugar. It occurs overwhelmingly in people with diabetes, which is why it’s most commonly called diabetic ketoacidosis, or DKA. In DKA, ketone levels in the blood can spike to 20 to 25 millimoles per liter, roughly five times higher than what the body produces during normal fasting or a ketogenic diet. That flood of acid drops blood pH to dangerous levels and can lead to coma or death without treatment.
How the Body Produces Too Many Ketones
Under normal conditions, insulin helps your cells absorb sugar from the bloodstream and use it for energy. When insulin is absent or severely deficient, cells can’t access that sugar. Blood glucose climbs, but your cells are effectively starving. In response, your body shifts to an emergency backup: breaking down stored fat.
That fat breakdown is driven by a combination of low insulin and high levels of counter-regulatory hormones, especially glucagon. Together, these hormones activate an enzyme that pulls apart fat stores, releasing fatty acids into the bloodstream. Those fatty acids travel to the liver, where they’re converted into a molecule called acetyl-CoA. In small amounts, the liver’s normal energy cycle can process acetyl-CoA without any trouble. But when the supply is overwhelming, the cycle gets saturated. The excess spills over into a different pathway that churns out ketone bodies, primarily one called beta-hydroxybutyrate.
In moderate amounts, ketones are a useful fuel source, and the brain can even run on them. The problem in DKA is volume and speed. Ketones are acidic, and when they accumulate faster than the body can buffer or excrete them, blood pH drops. That acidic shift disrupts how organs function, particularly the heart and brain.
Ketoacidosis vs. Nutritional Ketosis
People following a ketogenic diet sometimes worry that being “in ketosis” puts them at risk for ketoacidosis. These are fundamentally different states. During a ketogenic diet, beta-hydroxybutyrate levels typically reach about 4 to 5 millimoles per liter. During prolonged fasting, they may reach 5 to 6. In both cases, a functioning pancreas still produces enough insulin to keep ketone production in check. Blood pH stays normal.
In DKA, that insulin brake is broken. Ketone levels can soar to 20 to 25 millimoles per liter, and blood glucose often rises to two to nine times the normal range. Arterial pH drops below 7.35, sometimes as low as 7.20. Nutritional ketosis is a controlled metabolic state. Ketoacidosis is an uncontrolled crisis. The distinction is almost entirely about whether insulin is present to regulate the process.
Who Is at Risk
DKA is most closely associated with type 1 diabetes, where the immune system has destroyed the cells that make insulin. Without injected insulin, these patients have essentially zero natural production, making them vulnerable to DKA any time their insulin supply is interrupted.
But DKA is not exclusive to type 1. Some people with type 2 diabetes can develop it too, particularly during acute physical stress like a serious infection, surgery, or heart attack. A subset of type 2 patients, often described as having “ketosis-prone type 2 diabetes,” experience temporary failure of the insulin-producing cells under stress. This pattern has been most commonly reported in African American, Hispanic, and young Japanese populations. These patients are typically middle-aged, overweight, and have a family history of type 2 diabetes. Unlike type 1, they generally don’t need lifelong insulin and can return to oral medications once the crisis passes.
A newer risk factor involves a class of diabetes medications called SGLT2 inhibitors, which work by causing the kidneys to excrete excess sugar in urine. These drugs can trigger a form of DKA where blood sugar stays relatively normal (below 250 mg/dL), making it harder to recognize. This is called euglycemic DKA. Because of this risk, SGLT2 inhibitors are not recommended for people with type 1 diabetes and should be stopped immediately if DKA develops.
Common Triggers
DKA rarely strikes out of nowhere. It’s almost always set off by a specific event. The two most common triggers, according to the CDC, are illness and missed insulin. During an infection or other illness, stress hormones surge and blood sugar becomes harder to control. At the same time, nausea or vomiting may prevent someone from eating or taking medication normally. The combination creates a perfect storm for ketone buildup.
Other triggers include:
- Missed insulin doses or a malfunctioning insulin pump
- Heart attack or stroke
- Physical trauma, such as from a car accident
- Alcohol or drug use
- Certain medications, including corticosteroids and some diuretics
For some people, DKA is actually the first sign they have diabetes at all. This is especially common in children and young adults with undiagnosed type 1 diabetes.
Symptoms to Recognize
DKA symptoms often build over hours, though they can develop faster during illness. Early warning signs include excessive thirst, frequent urination, and fatigue. These overlap with general high blood sugar symptoms, which is why they’re easy to dismiss.
As ketone levels rise and the blood becomes more acidic, symptoms escalate: nausea, vomiting, and abdominal pain are common. Breathing may become rapid and deep as the lungs try to blow off excess acid in the form of carbon dioxide. One distinctive sign is fruity-smelling breath, caused by acetone (a type of ketone) being exhaled through the lungs. Confusion and difficulty staying alert signal that the brain is being affected, and this is a sign that the situation is becoming critical.
What Happens During Treatment
DKA is treated in a hospital, typically in an emergency department or intensive care unit. Treatment targets three problems at once: dehydration, insulin deficiency, and electrolyte imbalances.
Fluid loss in DKA averages 6 to 9 liters, so the first priority is aggressive rehydration through an IV. This alone helps lower blood sugar by diluting the bloodstream and improving kidney function. Insulin is given intravenously to stop fat breakdown, halt ketone production, and allow cells to start absorbing glucose again. Doctors won’t start insulin until fluids are flowing, because giving insulin without rehydration can worsen dehydration.
The third piece is electrolyte replacement, especially potassium. Even though blood potassium levels may look normal or high on initial lab work, the body’s total potassium stores are depleted. As insulin is given and acid levels correct, potassium rushes back into cells, and blood levels can drop dangerously low. This can cause heart rhythm problems, so potassium is carefully monitored and added to IV fluids throughout treatment. The acidosis itself generally corrects on its own once insulin is working and ketone production stops.
Preventing DKA
Most DKA episodes are preventable. The single most important step is never skipping insulin, even when you’re feeling sick and not eating. Illness actually increases insulin needs, so reducing or stopping doses during a stomach bug is one of the most common paths to DKA.
Checking for ketones during illness is a straightforward safeguard. Over-the-counter urine ketone test strips are widely available at pharmacies. If you have diabetes and are sick, vomiting, or noticing blood sugars that won’t come down, testing your urine for ketones can catch the problem early. If ketones are present, that’s a signal to get medical help quickly rather than wait and see. Catching DKA in its early stages, before severe dehydration and acidosis set in, makes treatment faster and dramatically reduces the risk of serious complications.