Excerpt

A 54-year-old Caucasian postmenopausal woman with type II diabetes mellitus, on insulin therapy for 5 years, and hypercholesterolemia presented to the emergency department with complaints of nausea, diarrhea, and vomiting for 1 day. On examination, she was short of breath, her heart rate was 130 beats/minute and regular, blood pressure was 140/78 mm Hg, and respiratory rate was 35 breaths/minute. Cardiac examination was unremarkable and the lungs were clear to auscultation. The laboratory results were consistent with diabetic ketoacidosis (DKA): arterial blood gas pH = 7.00, anion gap = 28, serum blood glucose = 462 mg/dL, serum acetone positive and urine positive for ketones. She had no prior history of coronary artery disease and no difficulty in controlling her blood glucose levels until one day prior to admission. In reviewing her social history, she was content with her work and family life, with no history of drug or alcohol use and no emotional stressors. ECG showed a sinus tachycardia with nonspecific T wave flattening in leads V3 through V6 (Figure 1). Serial ECG’s remained unchanged. Her chest x-ray revealed a perihilar distribution of interstitial markings with subtle curly B-lines, consistent with incipient congestive heart failure. The cardiac enzymes were elevated, CK = 129 units/L (normal range: 0-128 units/L), CK-MB = 10.6 ng/mL (normal range: 0-10 ng/mL), and Troponin I = 1.14 ng/mL (normal range: 0.00-0.04 ng/mL), and peaked 22 hours after her admission. She was admitted to the medical intensive care unit (MICU) for management of ketoacidosis. The DKA resolved quickly and she was transferred to a regular medical floor within 24 hours after admission. In view of an elevation in cardiac enzymes, she was suspected to have a non-Q wave myocardial infarction, although she denied any complaints of chest pain. She underwent detailed cardiac workup including echocardiogram, stress-rest perfusion imaging, and cardiac catheterization. Nuclear stress-rest perfusion imaging study was performed on the third hospital day. She underwent pharmacological stress using 5 minutes adenosine infusion protocol. Her heart rate changed from 115 to 137 beats/minute and blood pressure from 126/86 to 156/95. There was no chest pain. The ECG showed sinus rhythm, nonspecific ST-T wave changes, no Q waves and was unchanged from admission ECG (Figure 1). There was no change with adenosine infusion. Eleven mCi of ^99mTc-sestamibi was injected during adenosine stress and was followed by gated SPECT imaging 1 hour later, and 35 mCi of ^99mTc-sestamibi was used for resting imaging 3 hours later.

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