A 28-year-old woman with a history of hypertension and medication changes presents with severe hypertension. What is the most likely cause of her symptoms?

In young women, especially those around the age of 28, one of the leading causes of secondary hypertension is fibromuscular dysplasia. This condition is characterized by abnormal growth and development of the arterial wall, often affecting the renal arteries, which can lead to significant hypertension.

In this patient, who has a history of hypertension and recent medication changes, the abrupt increase in blood pressure could indicate that the medications are not adequately controlling her hypertensive state or that there is an underlying condition exacerbating her hypertension. Fibromuscular dysplasia is notable for causing renovascular hypertension, which can present suddenly, especially if there has been a change in the patient’s health status or if a medication that previously managed her blood pressure is no longer effective.

While conditions such as chronic kidney disease, hyperthyroidism, and coarctation of the aorta can also lead to secondary hypertension, fibromuscular dysplasia is more prevalent in younger women and can manifest with severe hypertension. Therefore, in this scenario, fibromuscular dysplasia is the most likely cause of her severe hypertension.