PANCE® Question of the Day: Candida

Prepare for the PANCE with this challenging clinical scenario that tests your ability to diagnose and manage a common yet serious condition. A 32-year-old woman presents with frequent urination, increased thirst, and recurrent yeast infections. Her family history includes diabetes mellitus and hypothyroidism, and her physical exam reveals skin changes associated with insulin resistance. Which laboratory study will most likely confirm your primary diagnosis? Explore the clinical details to make an informed decision.

A 32-year-old woman presents to the office for evaluation of frequent urination and increased thirst for 6 months without associated dysuria or hematuria. She has had vaginal itching with increased thick, white vaginal discharge without odor. She has used over the counter treatments 2 times in the past 3 months to treat possible yeast infections, but the discharge and itching returns. She has no known medical history and does not have a primary care provider. Family history is significant for diabetes mellitus in her mother and older sister, as well as hypothyroidism in her sister. Temperature is 36.9°C (98.5°F), pulse is 82/minute, blood pressure is 140/82 mmHg, BMI is 30. Skin examination reveals multiple skin tags on her neck and axilla and darkened, velvety skin on her neck. Cardiac and pulmonary examinations are unremarkable. On genitourinary examination, she has vulvar erythema and edema, with white, thick discharge. Wet mount of the vaginal discharge confirms the presence of candida. Which of the following laboratory studies is most likely to confirm this patient’s primary diagnosis? 

A. Hemoglobin A1C 

B. Urinalysis 

C. Complete Blood Count 

D. Complete Metabolic Panel 

E. Thyroid panel 


Scroll down to find the answer!                       

The correct answer to today's PANCE® Question is...

A. Hemoglobin A1C 

Before we get to the Main Explanation, let's look at the incorrect answer explanations. Skip to the bottom if you want to see the correct answer right away!

Incorrect answer explanations

The incorrect answers to today's PANCE® Question are...

B. Urinalysis 

Incorrect: The patient is presenting with complaints of frequent urination, and also has vaginal discharge and itching. While a urinalysis is reasonable to evaluate for urinary tract infection, the most likely underlying diagnosis is type 2 diabetes mellitus which would be confirmed with a hemoglobin A1C.

C. Complete Blood Count

Incorrect: This patient presents with frequent urination without dysuria, increased thirst, and recurrent vaginal yeast infections. Type 2 diabetes mellitus is the most likely underlying condition which can be diagnosed with a hemoglobin A1C. 

D. Complete Metabolic Panel 

Incorrect: Complete metabolic panel should be done as part of the workup in patients diagnosed with diabetes. Assessing renal function and having a baseline is important, but it would not diagnose diabetes mellitus. 

E. Thyroid panel 

Incorrect: This patient presents with a history of yeast infections, polyuria, polydipsia, and a family history of diabetes mellitus suggesting a diagnosis of diabetes mellitus type 2. This would not be diagnosed with a thyroid panel. 

Main Explanation

This patient presents with classic symptoms of diabetes mellitus (polyuria and polydipsia) and recurrent yeast infections. Hyperglycemia increases the risk for bacterial and fungal infections which explains her recurrent yeast infections. Combined with her physical examination findings and family history, diabetes mellitus type 2 is the most likely diagnosis.

The diagnosis of diabetes mellitus can be made using the glycated hemoglobin A1C (HbA1C) or plasma glucose concentration (fasting, random, or 2 hour glucose tolerance test). HbA1C is the most widely used test to estimate mean glucose using glycated hemoglobin. The level of glycated hemoglobin shows the mean plasma glucose level during the previous 1-3 months. HbA1C values 5.7-6.4% are consistent with a diagnosis of pre-diabetes, while values ≥ 6.5% confirm a diagnosis of diabetes mellitus. Prediabetes is a precursor to diabetes in which patients may be asymptomatic with elevated blood sugars. It is important to identify and intervene to prevent progression to diabetes mellitus.   

Fasting plasma glucose is obtained from a blood sample after the patient has fasted for 8 hours. Values 100-125 mg/dL are consistent with a diagnosis of pre-diabetes, while a level ≥ 126 mg/dL is consistent with diabetes mellitus.  A glucose tolerance test measures plasma glucose levels both before and 2 hours after a patient has ingested 75 grams of glucose. Pre-diabetes is diagnosed with levels 140-199 mg/dL. While diabetes mellitus is diagnosed when levels are ≥ 200 mg/dL. Lastly, a random blood glucose ≥ 200 mg/dL in patients presenting with classic symptoms of diabetes mellitus (polyuria, polydipsia, polyphagia and weight loss) is diagnostic of diabetes mellitus. 

Obtaining levels for glutamic acid decarboxylase (GAD65 antibodies), islet cell (ICA2 antibodies), and C-peptide helps to differentiate between type 1 and type 2 diabetes mellitus. Positive GAD65 or ICA2 antibodies with low C-peptide levels confirms a diagnosis of type 1 diabetes mellitus.  

Major Takeaway

Patients presenting with classic symptoms of diabetes mellitus or risk factors for diabetes mellitus should be evaluated with bloodwork. Diagnosis can be made using hemoglobin A1C or the plasma glucose concentration (fasting, 2 hour glucose tolerance test, or random glucose).  

References

American Diabetes Association; Standards of Care in Diabetes—2023 Abridged for Primary Care Providers. Clin Diabetes 2 January 2023; 41 (1): 4–31. https://doi.org/10.2337/cd23-as01 

Vijan, S. (2019). Type 2 diabetes. Annals of Internal Medicine, 171(9). https://doi.org/10.7326/aitc201911050  

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