A 25-Year-Old Female With Polyuria and Polydipsia
Gina Rossetti, Eric Hsieh
How does the history help narrow your differential diagnosis?
This is a 25-year-old female with a history of diabetes now presenting with urinary symptoms suggestive of a urinary tract infection (UTI). Diabetic ketoacidosis must be considered in diabetic patients who have infections, abdominal catastrophes, medication noncompliance, and myocardial infarctions.
What is your differential diagnosis?
Considering the patient’s elevated glucose, anion gap of 28, acidosis, and precipitating UTI, she likely has diabetic ketoacidosis (DKA).
What is the definition of diabetic ketoacidosis?
Although there is no consensus on the definition of DKA, the diagnosis requires the presence of an anion gap, metabolic acidosis, and ketonemia. Although they are usually hyperglycemic, 1 to 7% of patients may have a glucose level less than 200 mg/dL. In other words, you have to have the D (diabetes), the K (ketonemia), and the A (acidosis) to call it DKA.
What are the most common precipitating factors of DKA?
The most common precipitating factor is infection. A UTI and pneumonia are the two most common sources, although it is important to consider a less obvious source such as bacteremia, cellulitis, occult sinusitis, tooth abscess, or perirectal abscess. Other common precipitating factors include a new diagnosis of diabetes and lack of insulin compliance. Patients can also present with an abdominal catastrophe such as cholecystitis, pancreatitis, appendicitis, diverticulitis, perforated viscus, or acute ischemic bowel. Less common causes include myocardial infarction, pregnancy, drugs (glucocorticoid, β-agonists, cocaine, pentamidine), and stroke. Many times, however, no precipitating factor is identified.

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