Differential Diagnosis for 68 F with HTN, COPD, and Recent Lab Results

Single Most Likely Diagnosis

• Dehydration: The patient's low sodium level (135 mmol/L), high BUN/Creatinine ratio (21.0), and elevated glucose level (111 mg/dL) suggest dehydration, which is a common issue in patients with COPD, especially in the elderly. Dehydration can lead to a decrease in blood volume, causing a decrease in renal perfusion, which in turn can cause an increase in BUN and creatinine levels.

Other Likely Diagnoses

• Diabetes Mellitus: The patient's elevated glucose level (111 mg/dL) suggests diabetes mellitus, which is a common comorbidity in patients with hypertension and COPD.
• Chronic Kidney Disease (CKD): Although the patient's eGFR is within the normal range (79 mL/min/1.73m2), the high BUN/Creatinine ratio and elevated creatinine level (0.81 mg/dL) suggest possible CKD, which is a common comorbidity in patients with hypertension and COPD.
• Hyperlipidemia: The patient's elevated cholesterol (297 mg/dL), triglycerides (150 mg/dL), and LDL (188 mg/dL) levels suggest hyperlipidemia, which is a common comorbidity in patients with hypertension and COPD.

Do Not Miss Diagnoses

• Adrenal Insufficiency: Although less likely, adrenal insufficiency can cause hyponatremia (low sodium level), hyperkalemia (high potassium level), and hypotension, which can be life-threatening if missed. The patient's low sodium level (135 mmol/L) and high BUN/Creatinine ratio (21.0) warrant consideration of this diagnosis.
• Pulmonary Embolism: COPD patients are at increased risk of pulmonary embolism, which can cause dehydration, hypoxia, and hypercapnia. Although the patient's lab results do not directly suggest pulmonary embolism, it is a potentially life-threatening condition that should not be missed.

Rare Diagnoses

• Pheochromocytoma: This rare tumor can cause hypertension, hyperglycemia, and hypokalemia (low potassium level). Although the patient's lab results do not directly suggest pheochromocytoma, it is a rare diagnosis that should be considered in patients with unexplained hypertension and hyperglycemia.
• Multiple Myeloma: This rare cancer can cause hypercalcemia (high calcium level), anemia, and renal insufficiency. Although the patient's lab results do not directly suggest multiple myeloma, the elevated total protein level (8.0 g/dL) and high calcium level (10.0 mg/dL) warrant consideration of this diagnosis.