AANP Family Nurse Practitioner (FNP) Certification ExamDiagnosisEasy

A 48-year-old male presents with a 2-week history of nocturnal polyuria, polydipsia, and fatigue. He denies weight loss but reports increased appetite. On examination, his BMI is 32 kg/m², and blood pressure is 140/85 mmHg. Random plasma glucose is 280 mg/dL (15.5 mmol/L). Which of the following is the most appropriate initial diagnosis?

  1. ADiabetes Insipidus
  2. BType 2 Diabetes Mellitus
  3. CSecondary Diabetes
  4. DType 1 Diabetes Mellitus
Show answer & explanation

Correct answer: B. Type 2 Diabetes Mellitus

The patient's age, obesity (BMI 32), classic symptoms of polyuria and polydipsia, and a significantly elevated random plasma glucose (280 mg/dL) are all consistent with a new diagnosis of Type 2 Diabetes Mellitus.

Why the other options are wrong

  • A. Diabetes Insipidus involves polyuria and polydipsia but is due to a deficiency in ADH or renal unresponsiveness to ADH, resulting in dilute urine and normal or slightly elevated blood glucose.
  • C. Secondary diabetes refers to diabetes caused by other conditions (e.g., pancreatitis, Cushing's syndrome) or medications, which is not indicated in this initial presentation.
  • D. Type 1 Diabetes Mellitus typically presents in younger individuals, often with more acute and severe symptoms, and is characterized by autoimmune destruction of pancreatic beta cells.

Type 2 Diabetes Mellitus

A chronic metabolic disorder characterized by high blood sugar levels due to insulin resistance and/or insufficient insulin production.

  • Strongly associated with obesity and sedentary lifestyle.
  • Symptoms include polyuria, polydipsia, fatigue, and blurred vision.
  • Managed with lifestyle changes, oral medications, and sometimes insulin.

Memory trick: THIRSTY: Type 2, Heavy, Insulin-Resistant, Symptoms, Tests (glucose high).

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