Differential Diagnosis

The patient presents with hypertension, hypokalemia, and an elevated aldosterone-renin ratio, which guides the differential diagnosis. Here are the potential diagnoses categorized:

• Single Most Likely Diagnosis

  • C. Primary Aldosteronism (PA): The patient's elevated aldosterone-renin ratio (50 ng/dL per ng/mL/hr), hypertension, and persistent hypokalemia despite aggressive potassium supplementation are highly suggestive of primary aldosteronism. The low plasma renin activity (PRA) in the context of high aldosterone levels further supports this diagnosis.

• Other Likely Diagnoses

  • A. Pheochromocytoma: Although the plasma metanephrines are normal, which makes this diagnosis less likely, pheochromocytoma can cause episodic hypertension and palpitations. However, the lack of other supporting evidence (e.g., elevated metanephrines, paroxysmal symptoms) makes it less probable.
  • D. Hyperthyroidism: The patient's TSH is within the normal range, which does not support hyperthyroidism as a cause for her symptoms. However, thyroid dysfunction can sometimes present with subtle or atypical symptoms, and the slightly elevated glucose could be a minor indicator, though not strongly suggestive.

• Do Not Miss Diagnoses

  • B. Adrenal Insufficiency (AI): Although the cortisol level is provided and is not indicative of adrenal insufficiency, AI can sometimes present with hypotension, but it can also be seen with hypertension in certain contexts (e.g., with mineralocorticoid deficiency). The key here is that AI is a potentially life-threatening condition if missed, especially in a patient with a complex presentation.
  • Renal Artery Stenosis or Other Renovascular Diseases: Not directly listed but important to consider given the patient's hypertension and hypokalemia. These conditions could lead to secondary aldosteronism but are critical to diagnose due to their implications for kidney function and blood pressure management.

• Rare Diagnoses

  • Liddle Syndrome: A rare genetic disorder characterized by excessive sodium absorption and potassium wasting in the kidneys, leading to hypertension and hypokalemia. The presentation could mimic primary aldosteronism, but it's much rarer and typically diagnosed at a younger age.
  • Apparent Mineralocorticoid Excess: Another rare condition where the body has an abnormality in metabolizing cortisol, leading to an excess of mineralocorticoid effect, causing hypertension and hypokalemia.
  • Glucocorticoid-Remediable Aldosteronism: A rare form of primary aldosteronism caused by a genetic mutation leading to aldosterone overproduction that can be suppressed with glucocorticoids.

Each of these diagnoses has implications for the patient's management and prognosis, emphasizing the importance of a thorough diagnostic workup.