Which of the following is NOT a cause of secondary hypertension?

Chronic hypertension can be classified as primary (essential) or secondary, with secondary hypertension stemming from identifiable underlying conditions. In the context of secondary hypertension, conditions such as chronic kidney disease, obstructive sleep apnea, and pheochromocytoma are well-known contributors.

Chronic kidney disease leads to hypertension through mechanisms like fluid overload, activation of the renin-angiotensin-aldosterone system (RAAS), and disturbances in sodium handling. Obstructive sleep apnea can cause significant hypertension due to intermittent hypoxia and increased sympathetic nervous system activity. Pheochromocytoma, a tumor of the adrenal gland that secretes catecholamines, causes episodes of severe hypertension through increased vascular tone and cardiac output.

In contrast, hypercholesterolemia refers to high levels of cholesterol in the blood, which is primarily a risk factor for atherosclerosis and cardiovascular disease rather than a direct cause of hypertension. While high cholesterol can contribute to vascular health issues, it does not cause hypertension through the same mechanistic pathways as the other options listed. Thus, hypercholesterolemia does not fit the criteria of an identifiable cause of secondary hypertension.