What is Diabetic Ketoacidosis (DKA)?
Diabetic Ketoacidosis, or just DKA for short, is a severe complication of diabetes. This occurs when there are high sugars combined with a severe lack of insulin, causing the body to suddenly break down fat stores for energy to use ketone bodies as fuel. This leads to severe acidosis, which can cause the patient to be very sick.
Patients with DKA are usually admitted to the ICU.
What causes dka?
In order to understand DKA, we need to have a decent understanding of acid/base balance.
The pH will determine how acidic something is. This scale goes from 0 being the most acidic, to 14 being the most basic (or alkalotic). A pH of 7 is considered completely neutral.
The human body’s normal pH is almost completely in the middle, but slightly basic.
The normal pH of the blood is 7.35 – 7.45, with 7.40 being the sweet spot.
There are two main organ systems that work together to maintain pH balance. These systems are your respiratory system and your renal system, referred to as your “metabolic system” when talking about acidity.
The number of hydrogen ions present in the blood will determine how acidic it is. The more hydrogen ions = the more acidic. The kidneys system will release buffers to lower the pH if it is too high, as well as excrete more hydrogen ions into the urine to decrease the acidity.
At the same time, the respiratory system may increase or decrease the respiratory rate to alter the pH. Breathing out more carbon dioxide out will decrease the overall pH.
Oxygen (O2) to carbon Dioxide (CO2)
Oxygen is breathed into the lungs, transported by the red blood cells, and then delivered to the cells of the body. The cells use the oxygen o create energy through a process called the “Krebs cycle”. A byproduct of this energy creation is carbon dioxide (CO2), which is then breathed out during exhalation.
Whenever the cause of the acidity decreases serum bicarb levels, this is called metabolic acidosis. Whenever the root cause of acidity causes a buildup of carbon dioxide, this is called respiratory acidosis. Metabolic alkalosis and respiratory alkalosis work the same, but with high bicarb and low carbon dioxide, respectively.
(You probably should just check out my ABG article for more info!)
DKA is one of the most common types of metabolic acidosis. This is multifactorial in nature but is characterized by a rapid increase in circulating ketone bodies, which are acidic.
Because there is a complete or severe lack of insulin, glucose is unable to get into the cells to provide energy – since the cells use insulin to help transport glucose across the cell membrane. When this happens, the body starts to freak out. This causes a massive body response by breaking down fat cells to use ketone bodies.
Ketone bodies can passively cross the cell membrane without insulin, so they can provide much-needed energy to cells that are literally starving. The ketone bodies that are created are acetoacetic acid, Beta-hydroxybutyrate, and acetone.
Acetone is actually neutral – it is not acidic. However, its presence likely means there is a presence of other ketone bodies, which ARE acidic. Not every lab will be able to check for beta-hydroxybutyrate.
What is the “Anion Gap”?
You will often hear talk about the Anion gap when it comes to DKA and acidosis in general, but what exactly is the Anion Gap?
The anion gap (AGAP or AG), measures the difference between negatively charged and positively charged electrolytes in the blood. Positively charged particles are called cations, and negatively charged particles are called anions.
So essentially, this is the positive electrolyte (Sodium) minus the negative electrolytes (Chloride PLUS Bicarbonate).
What about Potassium?
Potassium is a cation, but levels are low in comparison to sodium, chloride, and bicarb because most of its content is stored intracellularly, so this doesn’t really impact the anion gap by much. Most calculations now exclude it.
DKA vs Hyperglycemic Hyperosmolar State (HHS)
Many type 2 diabetics that have uncontrolled sugars that do not often have DKA. This is probably because they still produce some insulin from their pancreas.
Hyperglycemic Hyperosmolar State (HSS) is another complication that can occur due to high blood sugars, which is more common in older patients with uncontrolled sugars.
Whenever blood glucose is high in the blood, patients can quickly become dehydrated. This is due to a process called osmotic diuresis.
Essentially, the sugar pulls a lot of water with it into the urine which is excreted by the kidneys. This dehydration causes what’s called hyperosmolality of the blood. Basically, the blood and extracellular fluid is super concentrated with sodium, so this pulls water out of cells, leading to cellular dehydration.
Because these patients usually have some level of insulin sensitivity and the presence of insulin, the massive shift of fat breakdown and ketone formation doesn’t occur on the same scale, which means severe acidosis doesn’t occur.
HHS is usually managed with IV fluids and subcutaneous insulin, but sometimes an IV drip is still used.
Patients who are in DKA are often obviously sick.
They often are vomiting, may have abdominal pain, and appear dehydrated and weak. In severe cases, they can also have some altered mental status, especially if they haven’t been able to drink fluids.
70-90% of cases of DKA occur in Type 1 diabetics and are usually due to an underlying cause. These causes include:
New Onset Type 1 DM
Patients who don’t know they are a type 1 diabetic yet
Noncompliance with insulin therapy
Patients who don’t take insulin as prescribed
If there is an infection, most commonly Pneumonia or UTI
Steroids, high-dose thiazide diuretics, dobutamine, terbutaline, second-generation atypical antipsychotics, or SGLT2 inhibitors
Cocaine use has been associated with recurrent DKA
Symptoms of DKA evolves rapidly over a 24-hour period, whereas HHS is more of a slow worsening of symptoms. Symptoms of DKA include:
Nausea or vomiting
May be from delayed gastric emptying and ileus (where a section of the intestinal wall does not perform peristalsis as normal)
Common in DKA, but almost never happens with HHS
Polyuria & Polydipsia
Increased urinating is due to the osmotic diuresis described above, and the increased thirst is due to the hyperosmolality of the blood
This is due to water losses, as well as fat losses from the massive lipolysis that occurs
Altered Mental Status
Lethargy, confusion, and/or obtundation can occur. Focal signs are possible as well. AMS tends to be worse in HHS because these patients often have a higher degree of hyperosmolarity.
The Physical Exam
Increased respiratory rate
This is termed Kussmaul respirations. This is the body trying to breathe off extra CO2 to compensate for the increased acidity caused by the DKA
Dry Mucous Membranes
Looking in their mouth and at their tongue is a great indicator of hydration status. These patients will be dry as a bone.
Your Other Senses?
You may notice a fruity odor coming from the patient’s mouth. This is the acetone that they are breathing out. Years ago, Nurse’s used to taste a patient’s urine as well to check for a sweet glucose taste, but that has fallen out of favor… although i’m not sure why…
Temp: Often normal, but may high if infection
HR: Often tachycardic due to dehydration +/- infection
BP: May be low with severe hypovolemia
SPO2: Usually normal
Respiratory Rate: often >20 rpm (Kussmaul respirations)
Heart: Fast and regular
Lungs: usually clear but frequent and deep
Patients in DKA are prone to severe electrolyte abnormalities such as hypokalemia, which can cause deadly cardiac arrhythmias to occur
Glucose monitors will often read “HI” if above 600 g/dL. However, even “euglycemic” DKA has occurred with near-normal glucose levels.
Any sick patient that may require ICU should have at least 2 IVs placed, preferably at least 20g. These patients will need a large volume of fluid replacement as well as will likely require an insulin drip and IV potassium.
Be sure to draw a gold top for the chemistries, and a lavender top for CBC. If a VBG is ordered, also draw a green top and place it on ice.
These patients are often visibly dehydrated and tachycardic. Hang 1-2L of NS open to gravity (and of course obtain an order to verify).
Ask for and administer medications such as Zofran or pain meds if the patient is nauseous or in severe pain
DKA WOrkup & Diagnosis
DKA is diagnosed based on lab work alone. The presence of a high anion gap PLUS a high sugar usually means DKA.
This is the level drawn either with a capillary glucose monitor or within the CMP of the labs. Patients in DKA often have blood sugars between 350-550 mg/dL
A high anion gap acidosis is the hallmark of DKA. The AGAP is usually >20 in DKA. This is usually due to the markedly reduced serum bicarb levels, as well as the accumulation of ketone bodies.
This is always elevated in HHS, but not always elevated in DKA. >295 mOsm/kg is considered hyperosmolar, and in HHS often levels exceed 320. Effective serum osmolality can also be calculated here.
Serum CO2 in the CMP is equivalent to Bicarb in an ABG.
If the CO2 aka Bicarb is lower than 18, this generally indicates metabolic acidosis.
Most patients with DKA are mildly hyponatremic (low sodium), but their levels will often appear even lower. This is because the high blood sugar pulls water out of cells and dilutes the sodium.
For an accurate sodium level, you should add 2 mEq/L for each 100mg increase in glucose above 100 mg/dL. You can also use this calculator.
Most patients with DKA and HHS have a total body deficit of 300-600 mEq of potassium.
This is because a lot of the potassium is urinated out along with water and ketones.
Lab levels usually appear normal and sometimes even elevated – but don’t be fooled!
Due to hyperosmolality and insulin deficiency, intracellular potassium moves out of cells and into the extracellular fluid.
Once insulin is administered, the potassium will be transported back into the cells, and the patient can be left with severely low potassium which can cause arrhythmias and even death.
Kidney function may be elevated from prerenal acute kidney injury from dehydration and hypovolemia. The patient may also have some diabetic nephropathy.
Most patients with DKA will have mild leukocytosis, and this is usually proportional to how many ketones are in the blood. It may also be related to cortisol and stress hormones as well.
A WBC > 25 or bands >10% should raise suspicion of infection.
ABGs are rarely needed in DKA. Remember DKA is metabolic acidosis, and there often is respiratory compensation.
If drawn, this means the pH will be acidic (< 7.35), the HCO3 will be low (<18), and the CO2 will also be low (<35) to compensate.
A VBG is often ordered instead of a full ABG in patients with suspected DKA. We are mainly evaluating the patient’s pH and bicarb levels, which are essentially equivalent to their ABG counterparts.
Serum ketones can be drawn to directly detect ketones within the blood. These do not need to be drawn if the patient has a AGAP acidosis with hyperglycemia, but will depend on the facility and ordering Provider.
Serum acetone or beta-hydroxybutyrate can both be ordered, and different hospitals will have different options.
A urinalysis will often show a decreased specific gravity from the osmotic diuresis. Additionally, it will often show large glucose and often ketones.
Starvation ketosis can occur in diabetics and non-diabetics when they aren’t eating, often accompanied by vomiting. This can lead to ketones in the urine and the blood, but there is no acidosis. This is not treated as DKA and is best treated with IV fluids with dextrose and antiemetics.
Amylase and lipase may be ordered if pancreatitis is suspected, and lipids may also be ordered (but usually with morning labs).
Treatment of DKA aims at reversing the acidosis as well as lower the glucose.
Each hospital and Provider may have their own protocols, but treatment generally involves these two steps:
IV Isotonic fluids
The first step in treating DKA is to replace IV fluids, usually with Normal Saline, which helps stabilize vital signs, replace fluid losses, increase insulin responsiveness, and reduce stress hormone levels.
Remember that severely high blood sugar causes severe dehydration, so these patients usually need a lot of fluid.
This is usually with 2-4L NS for the first 3-4 hours, infused at 1L per hour.
If the patient has a history of CHF or advanced renal failure, this should be infused slower with careful monitoring for fluid overload.
IV Insulin Drip
As long as potassium >3.3, Insulin can be started.
Each hospital will have their own insulin drip protocol. Often a bolus is given first of 10 units (0.1u/kg body weight). Then the infusion is started at 0.1u/kg/hr.
Regular and rapid-acting insulins are equally effective at treating DKA and HHS.
Once the serum glucose reaches between 200-300, dextrose is usually added to the IV fluid until the acidosis resolves.
If >5.3 mEq/L: IV Potassium is held off until levels drop below 5.3. These are checked hourly.
If 3.3 – 5.3 mEq/L: IV potassium is started as long as the patient is making >50ml/hr of urine, indicating appropriate renal function. 20-30mEq is usually added to each liter of IV fluid.
The goal is to maintain the potassium between 4 – 5 mEq/L.
If <3.3 mEq/L: The patient requires 20-40mEq/hr until the potassium is above 3.3. This is often added to NSS or ½ NS.
Insulin therapy should not be started until this level is above 3.3!
IV Potassium Rate
Potassium is very irritating to the veins and can lead to pain and phlebitis. Also, rapid infusion of potassium can result in severe hyperkalemia (Rule #1 of nursing: NEVER push IV potassium!).
Potassium shouldn’t exceed 10mEq/hour in a peripheral line, or 20mEq/hour in severe cases.
In a central line, potassium can be infused as fast as 20-40mEq/hr in severe cases.
More IV Fluids
After the first few hours, IV fluids should be continued at a slower rate. This will be selected by correcting the sodium level for hyperglycemia.
If the sodium level is still low, Normal saline is usually continued.
If the corrected sodium is normal, hypotonic saline is started (i.e. 1/2 NS).
These are usually continued at a rate between 250-300ml/hr.
IV FLUID TONICITY
Potassium is as osmotically active as sodium, so adding potassium to your saline will increase the fluid’s tonicity. To make a relatively “isotonic” solution, 40-60mEq of Potassium is often added to 1/2 NS.
Dextrose is also osmotically active, but the dextrose will be metabolized quickly, ultimately having less of an effect on the tonicity.
While it may seem counterintuitive, IV dextrose is added to the IV fluids once the blood sugar reaches somewhere between 200-300 mg/dL.
This is because insulin is still needed to “close the gap” and reverse the acidosis, but the glucose can still drop too much. If the blood glucose drops below 200-300mg/dL can increase the chance of cerebral edema!
In HHS, its best not to let the glucose drop below 250-300 mg/dL, and in DKA no less than 200 mg/dL.
An example of a fluid would be D5 1/2 NS (likely with potassium added as well).
Check out my article on IV FLUIDS!
Patients with DKA are at high risk for complications, so they should be monitored closely, especially while in the ICU.
Each hospital should have a facility protocol when it comes to insulin drips.
Usually, this requires blood glucose checks every hour.
Once the glucose drops below 250 mg/dL, fluid with dextrose is usually started until the AGAP normalizes, otherwise the patient will become hypoglycemic.
Lowering the glucose too much in these patients can lead to cerebral edema.
As discussed above, this should be monitored frequently.
A BMP is usually checked every 2-4 hours while on an insulin drip.
Cardiac Monitor / EKG
Monitor for tachycardia, ectopy, or any arrhythmias.
Severe hypokalemia and acidosis can lead to fatal arrhythmias like VFIB, Asystole, and PEA.
Significant acidosis and hypovolemia can cause hypotension.
When the body is acidotic, medications like vasopressors don’t work as well as they should.
Once the AGAP returns to normal, the gap is considered ‘closed” and the patient does not require an IV insulin drip anymore.
They are usually transitioned to subcutaneous insulin at this time.
Hopefully this left you with a good idea of what DKA is, how we recognize it, how we treat it, and what monitoring parameters you need to watch out for as a nurse!
What would you like to learn next? Let me know if the comments below!
Hirsch, I. B., & Emmett, M. (2022). Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Treatment. In T. W. Post (Ed.), Uptodate. https://www.uptodate.com/contents/diabetic-ketoacidosis-and-hyperosmolar-hyperglycemic-state-in-adults-treatment
Hirsch, I. B., & Emmett, M. (2022). Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Clinical features, evaluation, and diagnosis. In T. W. Post (Ed.), Uptodate. https://www.uptodate.com/contents/diabetic-ketoacidosis-and-hyperosmolar-hyperglycemic-state-in-adults-clinical-features-evaluation-and-diagnosis
Hirsch, I. B., & Emmett, M. (2022). Diabetic ketoacidosis and hyperosmolar hyperglycemic state in adults: Epidemiology and pathogenesis. In T. W. Post (Ed.), Uptodate. https://www.uptodate.com/contents/diabetic-ketoacidosis-and-hyperosmolar-hyperglycemic-state-in-adults-epidemiology-and-pathogenesis
Melmed, S., Koenig, R., Rosen, C., Auchus, R., & Goldfine, A. (2019). Type 1 Diabetes Mellitus. In Williams textbook of endocrinology (12th ed., pp. 1453 – 1457). Elsevier.