Continuing Education Activity

Euglycemic diabetic ketoacidosis (EDKA) is an uncommon diabetic complication associated with several risk factors such as fasting, surgery, pregnancy, and now the use of sodium-glucose cotransporter 2 (SGLT2) inhibitors. EDKA is primarily related to an imbalance between insulin and counter-regulatory hormones, with an elevated glucagon/insulin ratio. EDKA can lead to serious complications, including significant dehydration, if not recognized early and treated appropriately with fluids, dextrose, and insulin. This educational activity reviews the diagnosis and treatment of EDKA and highlights the role of the interprofessional team in evaluating and treating patients with this condition.

Objectives:

• Summarize the diagnostic criteria for euglycemic diabetic ketoacidosis.
• Describe the pathophysiology involved in euglycemic diabetic ketoacidosis.
• Identify the associated risk factors for patients relative to euglycemic diabetic ketoacidosis.
• Outline and explain the important therapeutic interprofessional team interventions for euglycemic diabetic ketoacidosis.

Introduction

Euglycemic diabetic ketoacidosis (DKA, EDKA) is a clinical syndrome occurring both in type 1 (T1DM) and type 2 (T2DM) diabetes mellitus characterized by euglycemia (blood glucose less than 250 mg/dL) in the presence of severe metabolic acidosis (arterial pH less than 7.3, serum bicarbonate less than 18 mEq/L) and ketonemia. DKA is one of the most severe and life-threatening complications of diabetes mellitus and can be seen in a variety of conditions. However, the incidence of EDKA has grown with the introduction of sodium-glucose transporter 2 (SGLT2) inhibitors.[1] It also presents a diagnostic challenge for physicians due to the variety of etiologies and normal blood glucose levels, often resulting in delayed diagnosis.[2][3][4]

Etiology

There are many known causes of EDKA in patients with diabetes. The overall mechanism is based on a general state of starvation, resulting in ketosis while maintaining normoglycemia. Therefore, conditions like anorexia, gastroparesis, fasting, use of a ketogenic diet, and alcohol use disorder can lead to states of carbohydrate starvation and subsequent ketosis. Additional triggers for EDKA include pregnancy, pancreatitis, glycogen storage disorders, surgery, infection, cocaine toxicity, cirrhosis, and insulin pump use.[5][6][7] T1DM who underwent bariatric surgery patients experience DKA in over 20% of postoperative cases and may be especially prone to EDKA.[8]

The newer oral antidiabetic medication category of SGLT2 inhibitors, including canagliflozin, dapagliflozin, empagliflozin, or ertugliflozin, can also directly result in EDKA.[2][3][9][10][11][12][13] EDKA may be more common in patients with diabetes on SGLT2 inhibitors with lower body mass index and decreased glycogen stores.[1] Episodes can be triggered by surgery, infection, trauma, a major illness, reduced food intake, persistent vomiting, gastroparesis, dehydration, and reduced insulin dosages.[14]

On rare occasions, a patient in DKA may receive enough extra insulin to bring the blood sugar under 250 mg/dL.

Epidemiology

Approximately 2.6% to 3.2% of DKA admissions are euglycemic.[9][15] DKA-associated with the use of SGLT2 inhibitors has rates ranging from 0.16 to 0.76 events per 1000 patient-years in patients with type 2 diabetes. Blau et al. estimate that the SGLT2 inhibitors increase the risk of DKA in T2D patients by 7-fold.[16] 

Erondu et al. estimate an overall incidence of DKA from SGLT2 inhibitor use of approximately 0.1%.[17] Data on patients with type 1 diabetes who presented with DKA associated with SGLT2 inhibitors showed rates varying from 5 to 12%; however, euglycemia was not present in all cases.[10] SGLT2 inhibitors are not approved for use in patients with type 1 diabetes. Data associated with other causes of euglycemic DKA is scarce.

Pathophysiology

The underlying mechanism of EDKA is secondary to a carbohydrate deficit resulting in generalized decreased serum insulin and excess counter-regulatory hormones like glucagon, epinephrine, and cortisol. The increased glucagon/insulin ratio leads to increased lipolysis, increased free fatty acids, and ketoacidosis.[2][9][12] Ketone body production in EDKA is similar to DKA with acetoacetic acid, beta-hydroxybutyric acid (after acetoacetic acid reduction), and acetone (after acetoacetic acid decarboxylation). The resulting anion gap metabolic acidosis triggers respiratory compensation and the sensation of dyspnea, as well as nausea, anorexia, and vomiting. Volume depletion resulting from decreased oral intake, vomiting, and osmotic diuresis from glucosuria further exacerbates elevations in glucagon, cortisol, and epinephrine, worsening lipolysis and ketogenesis. Additionally, decreased gluconeogenesis by the liver occurs in fasting where hepatic glycogen is already depleted, or increased glucosuria by the kidneys contributes to EDKA.[3] 

Often the insulin-using patients do not recognize their symptoms as DKA because serum glucose is not elevated and may maintain or decrease their insulin dose.[1] If insulin dosing is adequate for glucose levels, it will prevent gluconeogenesis, resulting in euglycemia. EDKA can be considered a “partially treated DKA” in this setting.[9]

SGLT2 inhibitors (empagliflozin, canagliflozin, dapagliflozin) are a newer class of antidiabetic drugs that increase the risk of EDKA unrelated to the duration of exposure.[16][18][19] The use of SGLT2 inhibitors in T1DM is not recommended by the U.S. Food and Drug Administration and is discouraged because the risk of ketone-associated effects can be as high as 9%.[1][20][21] The risk of EDKA among T2DM patients on SGLT2 inhibitors may be higher in patients with beta-cell insufficiency and perhaps predict those at greater risk for evolving to T1DM.[20] The mechanism of action of SGLT2 inhibitors is to enhance excretion and block reabsorption of filtered glucose from the proximal convoluted tubule.[22] The loss of urinary glucose again creates a state of carbohydrate starvation and volume depletion, increasing the glucagon/insulin ratio and resulting in a state of severe dehydration and ketosis.[1]

Additionally, SGLT2 inhibitors have been found to directly stimulate the release of glucagon from the pancreas, further worsening the glucagon/insulin imbalance, as well as suppressing the removal of beta-hydroxybutyrate and acetoacetate by the kidneys.[22][23][24] Euglycemia is maintained due to the loss of urinary glucose [2][9][10][25][26] and SGLT2 inhibitor-triggered hypoinsulinemia.[27] SGLT2 inhibitors also increase ketone reabsorption, such that ketosis is common in patients taking SGLT2 inhibitors after a trigger such as pregnancy, alcohol, surgery, infection, or starvation.[9][18]

Pregnancy is a risk factor for EDKA because of the physiologic state of hypoinsulinemia and increased starvation. Increased levels of cortisol and placental lactogen result in insulin resistance, and episodes of vomiting or fasting can lead to exaggerated starvation ketosis.[28] Respiratory alkalosis leading to bicarbonate loss in the urine exacerbates the acidosis.[29] These factors, taken together, can result in starvation, euglycemia, and ketoacidosis by the previous mechanisms described.[2]

Alcoholic ketoacidosis may have a similar presentation to EDKA, with anorexia, vomiting, dyspnea, and significant anion gap metabolic acidosis and ketonemia. Some consider alcoholic ketoacidosis a subtype of euglycemic DKA, and both are associated with increased glucagon/insulin ratio.[1][9][15] The differentiating factors are that alcoholic ketoacidosis patients do not have diabetes or use diabetic medications and are more commonly present with hypoglycemia or after a severe alcohol binge.[26] Similarly, excessive alcohol consumption in a person with diabetes can destroy pancreatic beta cells, decrease gluconeogenesis, and decrease glycogen stores. Coupled with vomiting and carbohydrate starvation results in accelerated lipolysis, ketoacidosis, and EDKA.[2][9]

History and Physical

Signs and symptoms will vary on a case-by-case basis but will be similar in presentation to hyperglycemic DKA, although perhaps without polyuria, polydipsia, or severe mental status changes. EDKA patients can present with nausea, vomiting, shortness of breath, generalized malaise, lethargy, loss of appetite, fatigue, or abdominal pain. Patients may not have polydipsia or polyuria since serum glucose is normal. The onset can be more insidious compared to hyperglycemic DKA due to the mechanism of subacute starvation required to induce ketosis and dehydration. There may or may not be an inciting infection or stressors, such as pregnancy, surgery, pancreatitis, alcohol use, or fasting.[30]

Patients may present with deep, rapid breathing, known as Kussmaul respiration, which represents respiratory compensation for severe metabolic acidosis. They may have a fruity odor to their breath due to the loss of acetone. Tachycardia, hypotension, altered mentation, increased skin turgor and delayed capillary refill are all signs of total body fluid loss. In severe cases, severe dehydration and metabolic derangement can lead to hypovolemic shock, lethargy, respiratory failure, coma, and death.

Evaluation

An ill-feeling patient with diabetes with symptoms such as malaise, dyspnea, nausea, or vomiting should undergo screening with serum pH and blood or urine ketone testing.[3][31][32][33]

The initial laboratory evaluation of EDKA includes basic electrolytes, glucose, calcium, magnesium, creatinine, BUN, serum and urine ketones, beta-hydroxybutyric acid, arterial or venous blood gas analysis, lactic acid, chest radiograph, and electrocardiogram. Urine screening for ketones with nitroprusside reagent does not measure beta-hydroxybutyrate but detects acetone and acetoacetate. Serum levels of beta-hydroxybutyrate are typically greater than 3 mmol/L in EDKA (normal values less than 0.5 mmol/L). If an infection is on the differential, consider CBC with differential white blood cell count and blood cultures. Serum osmolality, to assess for an osmolar gap, and toxic alcohols should be sent to rule out toxic alcohol ingestion when suspected in any patient with severe, unexplained anion gap metabolic acidosis. Close attention should be paid to the anion gap to help narrow direct diagnosis, workup, and management.

As described previously, the patient will have normoglycemia (capillary blood glucose less than 250 mg/dL) in the presence of metabolic acidosis (pH less than 7.3) and a total decreased serum bicarbonate (less than 18 mEq/L). Serum and urine ketones must be elevated to make the diagnosis of EDKA. Lactic acid may be elevated but should not account entirely for the elevation in the anion gap. Leukocytosis may be present in the case of a concurrent infection; however, it is nonspecific and could also be due to hemoconcentration or stress, among other causes. Potassium levels will vary, but great attention should be paid to the level before starting therapy, as total body potassium is usually depleted. Hypomagnesemia and hypophosphatemia can be seen in starvation due to decreased total intake and increased losses. Mild hyponatremia may also be seen but is generally less severe than the “pseudo-hyponatremia” seen in profound hyperglycemic states.

Treatment / Management

Initial management should be directed toward fluid resuscitation, as patients usually present as profoundly dehydrated. Begin with the administration of isotonic saline or lactated ringers solution. The American Diabetes Association (ADA) recommends 1 to 1.5 L/hr isotonic fluids during the first 1 to 2 hours. Continuous insulin infusion should follow fluid replacement, contingent on serum potassium levels greater than 3.3 mEq/L, starting at a rate of 0.05 to 0.1 U/kg/hr. In contrast to DKA management, since serum glucose in EDKA is less than 250 mg/dL, dextrose 5% should initially be added to the fluids to avoid hypoglycemia and hasten clearance of ketosis.[34] Consider increasing the amount of dextrose to 10% if ketoacidosis persists on D5%.[27][35][27]

Potassium should also be carefully monitored as total body potassium levels will likely be depleted, and IV supplementation of potassium and other electrolytes may be needed. Blood glucose levels should be checked hourly, and electrolytes every four hours at a minimum, as is the standard for treating DKA. Patients taking SGLT2 inhibitors should have these medications discontinued as soon as the diagnosis is recognized and held until recovery from the acute illness.[10] Sodium bicarbonate infusions are not indicated, and even use in the setting of severe acidemia of pH less than 6.9 is controversial. Patients will generally require ICU admission for close hemodynamic and laboratory monitoring as well as frequent titration of insulin infusion.[2][36][37] 

Treatment with IV fluid resuscitation should continue until the anion gap closes and acidosis has resolved.

Differential Diagnosis

In patients presenting with anion gap metabolic acidosis, clinicians must consider a variety of possibilities early on. Infections, including pneumonia, genitourinary infection, and bacteremia, must be ruled out early in the diagnostic algorithm. In patients presenting with abdominal pain, consider intraabdominal infection and pancreatitis. Consider toxic alcohol (methanol, ethylene glycol) or paraldehyde ingestion, salicylate overdose, lactic acidosis, starvation ketosis, and pregnancy in the appropriate clinical setting.

Note that patients may have also recently administered insulin, contributing to the euglycemic presentation. The presentation is very similar to alcoholic ketoacidosis (AKA), except EDKA patients have diabetes, and AKA patients present after an alcohol binge more commonly have hypoglycemia and can be successfully resuscitated with crystalloid and dextrose without the requirement for insulin.

Prognosis

Most patients with EDKA recover well with prompt recognition and treatment. Delayed diagnosis and inadequate treatment, especially hydration without dextrose/insulin infusion, can lead to persistent acidosis, vomiting, and prolonged hospitalization. Prognosis is worse for small children and pregnant women. Rarely, severe cases of respiratory failure, hypovolemic shock, coma, and death. Death is rare in most EDKA cases; however, pregnant women are at greater mortality risk than the general population.

Complications

Euglycemic DKA can result in persistent vomiting, dehydration, hypoglycemia, hypovolemic shock, respiratory failure, cerebral edema, coma, seizures, infection, thrombosis, myocardial infarction, and death.[38] Maternal EDKA can increase the rate of fetal (up to 9%) and maternal mortality.[39][40]

Consultations

Consider consultation with a critical care intensivist and endocrinologist for severe cases. Pregnant women suffering from EDKA benefit from involvement with obstetric and maternal-fetal medicine consultants.

Deterrence and Patient Education

Vigilant monitoring of capillary or urine ketones by patients with diabetes, especially during episodes of nausea or illness, can diagnose EDKA before it becomes severe.

Although the SGLT2 inhibitors have been shown to have extra benefits on cardiovascular and kidney health, they are not recommended to be used in managing patients with T1DM because of the high risk of EDKA.[41][42][43]

Pearls and Other Issues

• Successful diagnosis is dependent on early screening with serum or urine ketones, even when serum glucose is normal, whenever EDKA is suspected.
• After volume expansion with crystalloid, the foundation of therapy is a combination of dextrose (5 to 10%) and insulin (0.05 to 0.1 u/kg/hr) infusion until acidosis resolves.
• Insulin infusion should not be avoided due to normal glucose levels but instead is essential to successful treatment.
• Ketosis does not resolve with intravenous crystalloid hydration alone.
• SGLT2 inhibitor treatment should be discontinued as soon as EDKA is diagnosed.
• Sodium bicarbonate infusion is not indicated.

Enhancing Healthcare Team Outcomes

Euglycemic DKA is becoming more prevalent with the appearance of the new SGLT2 inhibitors. However, it is important to recognize the variety of etiologies of a potentially fatal condition. Early diagnosis and initiation of treatment can significantly improve morbidity and mortality. In patients presenting with euglycemic anion gap acidosis, great care is necessary to rule out other causes, including sepsis, toxic alcohol ingestion, and alcoholic ketoacidosis, among others. Early IV crystalloid and prompt initiation of insulin and dextrose infusion are the primary treatment.

Treatment requires a team of interprofessional healthcare workers consisting of clinicians (MDs, DOs, NPS, or PAs), possibly including consultation with a critical care intensivist as well as an endocrinologist. Emergency and critical care nurses monitor patients, administer ordered treatments, and report changes to physicians so treatment can be optimized. The clinicians can also consult with the pharmacy regarding appropriate interventions and have them run a full medication reconciliation to check for drug interactions or agents that may contribute to EDKA. ALl interprofessional team members must be prepared to communicate with the rest of the team as they note any changes in patient status, including therapeutic failure. The observations must also be documented in the patient's health record so all interprofessional team members can access the same accurate patient data. In this way, appropriate corrective actions can be implemented. These interprofessional interventions are crucial to achieving better patient outcomes. [Level 5]