Diabetic Ketoacidosis and Necrotizing Soft Tissue Infection

Emergency medicine (EM) residents at all levels of education and medical students on EM rotation.

Diabetes is a chronic disease diagnosed in over 28 million people in the United States which causes serious acute complications and is responsible for more than two million ED visits per year.1,2 Diabetic ketoacidosis (DKA) is one of the most serious complications of diabetes; it is diagnosed with the triad of hyperglycemia, anion gap metabolic acidosis, and ketonemia. The most common cause of DKA is infection, but it can also be precipitated by medication noncompliance, cerebral vascular accident or transient ischemic attack, myocardial infarction, acute pancreatitis, new onset diabetes, and medication side effect, among other causes. Our case involves a patient in DKA that was precipitated by a severe life- and-limb-threatening, necrotizing, soft tissue infection (NSTI). Management includes prompt recognition, antimicrobial therapy, and surgical debridement.3.

At the end of this oral board session, examinees will: 1) Demonstrate the ability to obtain a complete medical history and physical exam. 2) Identify and appropriately treat DKA. 3) Identify, treat, and make appropriate consults for NSTI. 4) Demonstrate effective communication of the treatment plan with the patient.

This is an oral board case following a standard American Board of Emergency Medicine-style case in a tertiary care hospital with access to all specialists and resources needed.

This case was tested using 12 resident volunteers ranging from PGY 1 - 2 in an ACGME (Accreditation Council for Graduate Medical Education) accredited emergency medicine program in a virtual video conference setting. Practice candidates were seven PGY1 and five PGY2 level residents. Scoring measures of the ACGME core competencies were performed by program core faculty using a scale from 1 - 8 using the American Board of Emergency Medicine (ABEM) oral boards standard case rating. A debriefing session followed the case to discuss the critical actions and for the residents to rate their experience.

The average score for practice candidates per level was: PGY1: 4.4, PGY2: 5.7. Average critical action missed per level was: PGY1: 3.3, PGY2: 0.2. All candidates recognized the patient was in DKA, with varied confidence and comfortability in the appropriate potassium and insulin dosing. On average, practice candidates rated the case as 4.81 (1 - 5 Likert scale, 5 being that the case increased their medical knowledge). No significant modifications were made to the case following the practice session.

The aim of this case was to identify and treat two life-threatening diagnoses experienced by patients with diabetes, DKA and NSTI. There are many causes of DKA and the clinician should search for precipitating factors. The most common cause of DKA is infection, but it can also be precipitated by medication noncompliance (both in our case). Even with modern advances, diabetic soft tissue infections can progress to NSTI with high mortality at just over 20%.1. NSTI presentation is typically swelling, erythema, and pain out of proportion.3 Exam findings that lead to a higher index of suspicion of severe infection are bullae, necrosis, crepitus upon palpitations, and sometimes cutaneous anesthesia.4 Imaging modalities can help with diagnosis, but lack of air seen within soft tissue should not rule out NSTI. Suspected NSTI are typically polymicrobial and myonecrosis and should be treated with: 1) vancomycin (or linezolid), 2) either piperacillin/tazobactam, ampicillin/sulbactam, or a carbapenem, 3) clindamycin to decrease toxin production.2,4Initial treatment of DKA is isotonic fluids, and insulin therapy should be withheld until serum potassium levels are obtained since prolonged serum acidosis can drive potassium intracellularly. Patients with serum potassium ≤3.3mEq/L should receive potassium replacement prior to initiation of insulin. In adults, insulin can be started as a bolus of 0.1 units/kg body weight followed by 0.1 unit/kg per hour infusion. However, some studies have shown no benefit to insulin bolus in adults.5-6.

Diabetes, diabetic ketoacidosis, necrotizing soft tissue infection, gas gangrene, myonecrosis.