Diabetic ketoacidosis: Clinical sciences

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Introduction0:00–0:50

Diabetic ketoacidosis, or DKA for short, is a life-threatening complication of diabetes mellitus characterized by a severe insulin deficiency and glucagon excess.
It typically but not exclusively occurs in the setting of type 1 diabetes, with common triggers that include illness or infection, as well as known diabetes with suboptimal glycemic control or interruption in therapy.
The diagnosis of DKA relies primarily on blood work showing metabolic acidosis and hyperglycemia, as well as ketones in the urine.Now, if you suspect DKA, you should first perform an ABCDE assessment to determine if your patient is unstable or stable.

Unstable Patient0:50–1:14

DKA generally presents as unstable, so stabilize the airway, breathing, and circulation. Next, obtain IV access, and give a 1-liter bolus of isotonic IV fluid.
Finally, put your patient on continuous vital sign monitoring, including blood pressure, heart rate, and pulse oximetry, and provide supplemental oxygen, if needed.Once you stabilize the patient, obtain a focused history and physical exam.

Stable Patient1:14–2:01

History often reveals polyuria, polydipsia, and unintentional weight loss, as well as nausea, vomiting, and diffuse abdominal pain.
These are commonly associated with a recent precipitating factor like illness or infection. Additionally, there might be a known history of diabetes with inadequate glycemic control or recent disruption in therapy.On the other hand, physical exam might reveal a confused, somnolent patient with tachycardia, hypotension, and dry mucous membranes.
Also, you might see a pattern of deep, rapid breathing known as Kussmaul respirations, and a fruity odor to the breath.Based on these findings, suspect DKA.

Suspect DKA2:01–3:43

Next, order labs, including an ABG or VBG, CMP, and serum and urine ketones like beta-hydroxybutyrate. Next, review the lab results and assess diagnostic criteria for DKA, which include a blood glucose above 250 milligrams per deciliter, a pH below 7.3, and a serum bicarbonate level less than 15 milliequivalents per liter, indicating a metabolic acidosis.
Additional criteria includes an elevated anion gap, and elevated serum and urine ketones. If the DKA criteria are not met, you should consider alternative diagnoses.
On the other hand, if the lab results show that DKA criteria are met, you can diagnose DKA and begin insulin treatment. Here’s a clinical pearl to keep in mind!
There are several conditions that can mimic DKA. Hyperosmolar hyperglycemic state, or HHS for short, is most commonly seen in type 2 diabetes and presents with hyperglycemia, with blood glucose over 600 mg/dL, as well as hyperosmolarity.
But here’s the big difference; unlike DKA, in HHS there is no acidosis. On the flip side, like DKA, other conditions like starvation and alcoholic ketoacidosis can cause ketoacidosis, and in both of these conditions, blood glucose can be elevated, but it’s rarely over 200 mg/dL.
Ok, now that we’ve diagnosed DKA, let’s turn our attention to management. Start IV fluids, as well as a bolus of IV insulin, dosed at 0.1 unit per kilogram, followed by a constant IV insulin infusion at 0.1 units per kilogram per hour.

Management3:43–6:45

At the same time, pay attention to the serum potassium level, because insulin and fluid resuscitation can lower serum potassium levels.
If the serum potassium is above reference range, no potassium replacement is needed. On the other hand, if the serum potassium is below reference range or even within reference range, add potassium to the IV fluids.
In fact, if the potassium is below the reference range, it's actually necessary to replace potassium before even starting insulin!
Here’s a high-yield fact to keep in mind! In DKA, the acidosis causes potassium to leave the cells and enter the bloodstream.
However, as soon as you give insulin, that potassium is going right back in the cells, dangerously decreasing its blood levels.
So a modestly low potassium of 3 could quickly reach a lethal level of 2.5 if you start the insulin drip before appropriately replacing the potassium.
And now, a clinical pearl! Order a CMP every 2 to 4 hours to identify electrolyte imbalance, hold insulin infusion if potassium is low, and initiate replacement as appropriate.
But remember, DKA patients often have renal dysfunction, so be mindful that they may need more cautious potassium replacement.
Once potassium levels are normal, don’t forget to restart insulin. Once you do that, assess the corrected sodium level, as this will guide your choice of IV fluid therapy.
This is important because the elevated glucose increases serum osmolality, causing water to move from the intracellular to the extracellular space, artificially lowering the serum sodium.
The corrected sodium is equal to the measured serum sodium, plus 1.6 times the glucose concentration minus 100, divided by 100.
If the corrected sodium is within or above the reference range, start an infusion of half-normal saline, but if the corrected sodium is below the reference range, start an infusion of 0.9% normal saline.Here’s another high-yield fact!
Rapid fluctuations in serum osmolality can lead to cerebral edema, so you should be very cautious with fluid management.
Be on the lookout for signs and symptoms of cerebral edema, including headache, decreased consciousness, seizures, hypertension, and bradycardia.
If suspected, the recommended treatments include IV mannitol and mechanical ventilation. Now that you are done with the initial management, your next step is to assess your patient’s blood glucose after one hour.

IV insulin titration6:45–8:23

If the blood glucose is falling by more than 50 to 70 milligrams per deciliter per hour, your patient is having an adequate response, so continue the insulin infusion at the current rate.
On the other hand, if it's falling by less than 50 to 70 milligrams per deciliter per hour, your patient is having an inadequate response, so give another bolus of IV insulin and resume the insulin infusion at the previous rate.
Next, reassess the blood glucose every hour. If blood glucose is over 200 mg/dL, continue the insulin infusion and titrate if needed.
Continue to monitor blood glucose hourly until it drops below 200 mg/dL. Once the blood glucose falls below 200, decrease the IV insulin infusion rate, and add 5% dextrose to the IV fluid, to prevent hypoglycemia.Here’s a clinical pearl to keep in mind!
Hyperglycemia usually resolves before ketoacidosis does, so after the blood glucose falls below 200, continue to check the CMP, as well as the serum and urine ketones every 2 to 4 hours during treatment.
Once the pH is greater than or equal to 7.3, the bicarbonate level is greater than or equal to 15, and there’s minimal ketones, then the DKA has resolved, and you can stop the IV fluids.

IV to subcutaneous insulin8:23–9:14

Then, assess the CMP, and evaluate for the presence of precipitating factors, such as infection, illness, inadequate diabetes treatment, or new onset of type 1 diabetes.
Once the anion gap is closed and the precipitating factors are resolved, switch to a subcutaneous dose of fast-acting insulin along with a meal.
Be sure to discontinue the IV insulin infusion 1 to 2 hours after subcutaneous insulin is given. After transitioning to subcutaneous insulin, continue to monitor blood glucose every hour, with the goal of keeping the blood glucose between 150 and 200, while ensuring that your patient is tolerating oral intake.
Finally, don’t forget to provide diabetes education if your patient hasn’t received it yet.Alright, as a quick recap… If you suspect DKA, assess criteria to confirm the diagnosis.

Review9:14–10:19

Then, begin IV fluids and insulin, but don’t forget to check potassium and sodium levels, and correct any electrolyte abnormalities.
Next, assess the blood glucose after one hour, and if it’s decreasing by 50 to 70 mg/dL every hour, continue the current insulin infusion rate.
But if it’s decreasing by less than that, give another bolus of IV insulin and continue the previous insulin infusion rate.
Keep assessing the blood glucose hourly, and if the values remain over 200, continue insulin infusion and titrate as needed.
Once the blood glucose falls below 200, decrease the IV insulin infusion rate, add 5% dextrose to the IV fluids. When the anion gap is closed and precipitating factors are resolved, switch to subcutaneous insulin.
Finally, continue blood glucose monitoring every hour,