Diabetic Ketoacidosis (DKA)
DKA is occasionally the initial manifestation of diabetes, but it usually occurs in the context of known diabetes plus a trigger. This is especially true of patients with type-II DM, who don't generally require exogenous insulin but may develop DKA in the context of physiologic stress. Most triggers of DKA are benign (e.g., nonadherence, viral gastroenteritis). However, DKA can be caused by any source of physiologic stress. Occasionally, DKA is the presentation of a serious underlying problem, especially sepsis. Common triggers of DKA include:
- Absolute insulin deficiency:
- Insulin nonadherence.
- Inadequate dosing of basal insulin.
- Insulin pump failure.
- New diagnosis of diabetes.
- Steroid.
- Sympathomimetics.
- SGLT-2 inhibitors.
- Atypical antipsychotics.
- HIV protease inhibitors.
- Checkpoint inhibitors (e.g., pembrolizumab, nivolumab).
- Pentamidine. (32409703)
- Anti-calcineurin immunosuppressives. (10743693)
evaluation for the cause of DKA
- History and physical examination are the key here. If there is clear history of nonadherence, a big workup isn't necessary.
- Infectious trigger?
- DKA itself may cause leukocytosis, so a WBC elevation alone is nonspecific.
- Infection is suggested by fever, marked left-shift, or severe leukocytosis (>20,000-25,000). (3101715)
- DKA itself can cause abdominal pain. This creates diagnosis confusion – we must sort out whether the pain is due to DKA, or whether the pain represents an underlying problem (appendicitis, cholecystitis, etc). This may be sorted out in two ways:
- (#1) Severe pain with only mild ketoacidosis argues against DKA causing the pain. (12040551)
- (#2) When in doubt about the need for an abdominal CT scan, aggressively treat the DKA and follow serial abdominal examinations. If the abdominal pain is due to DKA, it will resolve as the ketoacidosis improves. If pain fails to resolve or gets worse, then further investigation is warranted.
- DKA itself may cause mental status changes, but this usually occurs when the calculated serum osmolality is >320 mOsm/kg. Abnormal mental status despite normal serum osmolality should trigger suspicion for a primary neurologic problem (e.g., meningitis, intracranial hemorrhage). (25905280)
- Another sign of a primary neurologic problem is if the mental status doesn't improve with treatment of the DKA. (Noting also that if mental status deteriorates during therapy, the possibility of cerebral edema should also be considered.)
fluid administration
#1) start with fluid boluses
- DKA patients are often profoundly volume depleted (e.g., due to vomiting, reduced oral intake, and osmotic diuresis). Hypovolemia triggers the release of stress hormones (e.g., catecholamines, cortisol) which cause insulin resistance and thereby exacerbate the DKA. So prompt reversal of hypovolemia is important.
- Most patients will require ~2-4 liters of crystalloid up front in the form of boluses (e.g. ~1,000 ml/hr).
- For young DKA patients with normal cardiorenal function, if the patient's heart rate is >100 b/m then they probably need more fluid.
- ⚠️ Ultrasound-guided fluid resuscitation is useful for patients with heart failure, or patients on hemodialysis.
#2) initial maintenance fluid infusion (if glucose >300 mg/dL or >17 mM)
- Once the patient is approaching a euvolemic state, a maintenance fluid infusion is generally started.
- The usual choice is an isotonic balanced crystalloid (lactated Ringer's or plasmalyte) at ~150-200 ml/hr.
- ⚠️ Patients with heart failure may tend to become overloaded with standard DKA protocols, so follow volume status with ultrasonography and consider using less fluid.
- If the glucose level is skip this step.
#3) after the glucose falls
- As the glucose falls, dextrose must be added to the IV fluid to allow for ongoing insulin administration (since ongoing insulin administration is needed to correct the ketoacidosis).
- A nice strategy here is to drop and split: (32771260)
- Cut the LR rate in half (e.g., from 200 ml/hr to 100 ml/hr).
- Add a D10w infusion at an equal rate (e.g. 100 ml/hr LR plus 100 ml/hr D10W). Note that D10W is fine for peripheral IV infusion, it doesn’t require a central line. The D10W can actually be infused together with the LR using a single intravenous line, because these two fluids are compatible.
- Combining LR with an equal volume of D10W effectively creates a solution of “D5 1/2 LR” (a solution which doesn't exist in pre-mixed bags). The advantage of giving the components separately is that it provides you greater control with regards to adjusting the amount of sodium you are giving versus the amount of dextrose. For example, if you want to give additional dextrose you can up-tirate the D10W infusion (without giving the patient more sodium and causing volume overload).
balanced crystalloid versus normal saline
- Balanced crystalloid is generally preferred (e.g. lactated Ringers), as this will avoid worsening the patient's acidosis. Evidence supports the ability of balanced crystalloid to accelerate resolution of DKA. (33196806)
- The advantage of using normal saline is that it is available in preformulated bags containing potassium chloride. In some hospital units, this is a more convenient strategy for potassium repletion. Using normal saline for resuscitation is fine, particularly if this is the only way to appropriately replete the patient's potassium. However, clinicians should be aware that using saline will promote the development of NAGMA that may require active management with intravenous bicarbonate later on (as discussed below).
electrolyte management
hypokalemia
- Hypokalemia is extremely problematic, because insulin cannot be given to patients with significant hypokalemia (since insulin will exacerbate the hypokalemia). Thus, hypokalemia impairs our ability to treat DKA.
- Hypokalemia may be treated with aggressive doses of IV potassium (e.g., 40 mEq/hr), with careful monitoring of electrolytes every hour. (24070967, 16191494, 28659865) To avoid damaging the veins, potassium may be given via a central line or via multiple peripheral lines (e.g., 20 mEq/hr simultaneously through two peripheral IVs).
- (More on hypokalemia management here.)
hyperkalemia
- Hyperkalemia is less of a problem, because the usual DKA resuscitation will naturally reduce potassium.
- In severe hyperkalemia, IV insulin is indicated (e.g. 10 unit IV insulin bolus). IV calcium may also be indicated.
- (More on hyperkalemia management here).
ongoing potassium repletion
- DKA resuscitation will cause the potassium to fall over time.
- Aggressive potassium repletion is generally needed, usually with repeated doses of IV potassium. Oral potassium can be used, but patients are often nauseous and unable to tolerate this.
- In the absence of renal failure, shoot for a potassium >5.3 mM (to avoid falling behind).
- In renal failure, be more conservative with potassium repletion.
- Potassium chloride is generally used. However, oral potassium citrate or IV potassium acetate may offer the advantage of reducing the chloride load and thus decreasing the tendency to develop NAGMA. .
magnesium repletion
- Maintaining a high-normal magnesium level may tend to protect against hypokalemia-induced arrhythmia, in case the potassium falls too low (isolated hypokalemia is usually well tolerated, whereas the combination of hypokalemia plus hypomagnesemia tends to cause torsade de pointes).
- (More on hypomagnesemia here).
phosphate repletion
- Phosphate will drop during treatment, especially in patients with severe DKA.
- Follow the phosphate and replete if substantial hypophosphatemia occurs (
- (More on hypophosphatemia here).
insulin infusion
general concepts of using insulin in DKA
- The primary problem with DKA is ketoacidosis (not hyperglycemia). Therefore, our overall goal is to titrate insulin as needed to treat the ketoacidosis (figure above).
- Unfortunately, it's a bit more complicated than this. Glucose levels are easier to repeat than measurements of ketoacidosis (e.g., the anion gap). Thus, glucose levels are often used as a surrogate measurement of the biological efficacy of insulin (for example, during the initial phase of resuscitation, if the glucose level isn't falling, that indicates that insulin isn't working and should be up-titrated).
- Every hospital will have a DKA protocol, which can generally be followed. However, it's still useful to understand the broad strokes of how insulin is utilized in DKA, as described below.
(#1) insulin infusion: getting started
- Unless the patient is hypokalemic (K
- Insulin bolus (10 units IV) is generally not recommended. However, an insulin bolus may be helpful in the following situations:
- (1) There is a delay in receiving an insulin infusion from the pharmacy. The main advantage of an insulin bolus is that this can usually be given immediately (most units have 10-unit insulin vials immediately available), whereas an insulin infusion needs to be mixed up in pharmacy).
- (2) For patients with severe acidosis (e.g., bicarbonate
(#2) up-titration of insulin infusion, if needed
- The insulin infusion should be up-titrated as needed, with a goal of dropping the glucose by 50-70 mg/dL (2.8-3.9 mM) per hour.
- Occasionally, if the patient's anion gap isn't clearing, you might need to simultaneously increase both the insulin infusion rate and the glucose infusion rate. (Remember, the insulin is being used to clear the ketoacidosis.)
(#3) cut back on the insulin infusion, but don't stop it
- Once the glucose falls to ~250 mg/dL (14 mM) the insulin infusion rate is typically reduced considerably (to ~0.05 U/kg/hr). (32771260, British guidelines)
- Avoid stopping the insulin infusion entirely, if possible. Hypoglycemia may generally be managed by the use of additional IV dextrose and down-titration of insulin (rather than shutting the insulin off entirely).
(#4) stop the insulin infusion only after the following criteria are met:
- (a) Resolution of ketoacidosis (anion gap < 10-12 mEq/L).
- An exception here is a patient with end-stage renal disease, who may chronically have an elevated anion gap due to uremia which never normalizes. In this situation, normalization of the beta-hydroxybutyrate level (
- Acidosis increases insulin resistance, so if the patient remains acidemic then there is an increased risk that the anion gap will open up.
- Many patients will develop a NAGMA, leading to a persistent acidosis that doesn't respond to insulin. This may be treated with IV bicarbonate as described below.
- If the insulin infusion is stopped and the patient doesn't eat anything or receive any IV glucose, this increases the risk of recurrent DKA.
- An exception can be made for patients with gastroenteritis or diabetic gastroparesis, who may not be hungry for several days. In this situation, the insulin infusion can be stopped, but patients should remain on low-dose intravenous glucose (e.g. D5W at 50-75 ml/hr). If the patient's glucose level increases, they should be treated with PRN short-acting insulin. Ongoing administration of carbohydrate plus PRN insulin will help prevent DKA recurrence.
(#5) start meal-associated & PRN insulin when the infusion is stopped
- Start meal-associated and sliding-scale insulin.
- If the patient isn't already on a prescribed regimen of meal-associated insulin, a dose of ~0.08 U/kg rapid-acting insulin per meal may be reasonable (i.e., about one third of the daily basal insulin requirement). Follow glucose carefully and titrate to effect.
long-acting basal insulin
concept of early basal insulin
- Long-acting insulin should be started early (well in advance of discontinuing the infusion). Glargine has a delayed onset compared to some older forms of insulin (e.g., NPH), so the traditional two-hour overlap may not work well with glargine. (28372715) Early initiation of long-acting insulin facilitates transitioning off the insulin infusion, reduces the incidence of hyperglycemia, and might decrease hospital length of stay. (28183452)
- (More on the rationale & evidence for early insulin here.)
step #1: determine the total daily requirement of long-acting insulin
- For patients on home subcutaneous insulin, this will be equal to the patient's home basal dose:
- For patients on once-daily long-acting insulin (e.g., glargine), that's their basal dose
- For patients on twice-daily basal insulin, add up all the basal doses given during a day.
- Some patients have a backup dosing regimen of long-acting insulin (e.g., a certain dose of s.q. long-acting insulin to use if their pump malfunctions). You can use that as their daily basal insulin dose.
- The basal insulin requirement may also be calculated from the pump's basal rate (e.g., multiply the basal rate times 24 hours to obtain the total daily basal requirement).
- Note that the patient's pump should be stopped and removed (more on this below)
step #2: give the full dose of basal insulin
- Provide the entire day's worth of basal insulin (typically in the form of glargine).
- If the glargine is given at an inopportune time (e.g. it’s given in the evening and the patient prefers taking it in the morning), the timing can be slowly shifted each day to meet the patient's preference.
common pitfalls with long-acting insulin
- Practitioners who are nervous about giving early glargine may sometimes give a reduced dose, which leads to tremendous confusion. Please give patients their full home-dose of basal insulin. Critical illness causes insulin resistance, so patients may have a tendency to require more insulin (not less).
- Some patients are on twice daily glargine (for reasons which aren't entirely clear to me). If such patients are continued on twice daily glargine, the insulin infusion shouldn't be stopped until after they receive their second dose of glargine. Alternatively, both doses can be compiled into a single daily dose (this is preferred as it may accelerate weaning off the insulin infusion).
- Glargine must be ordered “q24 hours,” rather than “daily.” If the glargine is electronically ordered as “daily,” then it may default to every morning at 9 AM – which will cause some patients to receive their daily dose in the evening, and then another dose the following morning. Please check and double-check the glargine dose and when it is scheduled to be delivered.
management of severe or refractory ketoacidosis
(#1) initial management of patients with severe ketoacidosis
- Some patients will present with profound ketoacidosis (e.g. pH
- Avoid giving bicarbonate during the initial resuscitative phase (for management of ketoacidosis). The proper treatment of ketoacidosis is insulin. Thus, if the patient has a severe ketoacidosis which requires aggressive management, the most effective strategy is to increase the insulin dose (usually along with administration of additional glucose and potassium):
- a) Don't wait for the insulin to arrive from pharmacy: bolus 10 units IV immediately.
- b) Consider starting an insulin infusion at 0.2 U/kg/hr in the sickest patients.
- High-flow nasal cannula is a safe way to support the patient's breathing (note that patients are not good BiPAP candidates, due to a tendency to vomit). High-flow nasal cannula may reduce the anatomic dead space, thereby reducing the work of breathing and avoiding respiratory fatigue.
- High-flow nasal cannula may be set as follows:
- FiO2 titrated to achieve a saturation >92% (usually a low FiO2 will be needed e.g., 30-40%)
- Increase the flow rate as high as the patient can tolerate (e.g., 60 liters/minute). The flow rate is what does the work of reducing dead space and thereby blowing off CO2. If the patient is very sick and air-hungry, they will tolerate high flow rates.
(#2) refractory ketoacidosis: if the anion gap is not closing
- If the anion gap isn't closing, consider the following possibilities:
- Inadequate fluid resuscitation.
- Inadequately low insulin dose.
- Malfunction of insulin infusion (e.g., line infiltration or infusion pump error).
- Festering, underlying problem which hasn't been addressed.
- Evaluate fluid status (e.g. with ultrasonography), provide additional crystalloid resuscitation if necessary.
- Consider increasing the insulin infusion rate (which may require a simultaneous increase in dextrose administration).
- Reevaluate for a missed underlying problem.
- Consider checking beta-hydroxybutyrate & lactate levels (to exclude an occult lactic acidosis).
- Make sure the infusion pump and IV catheter are functioning properly.
NAGMA management
the problem with non-anion-gap metabolic acidosis (NAGMA)