Renal Disease (e.g., Chronic Kidney Disease, Renal Artery Stenosis): This is a common cause of secondary hypertension in young individuals. Renal issues can lead to fluid retention, electrolyte imbalances, and activation of the renin-angiotensin-aldosterone system, resulting in high blood pressure.

Pheochromocytoma: A rare tumor of the adrenal gland that produces excess catecholamines, leading to episodic or sustained hypertension. Although less common, it's a significant consideration in young patients with hypertension.
Hyperaldosteronism (Primary Aldosteronism): Excess production of aldosterone leads to sodium retention, water retention, and potassium loss, causing hypertension.
Coarctation of the Aorta: A congenital condition characterized by narrowing of the aortic isthmus, leading to increased blood pressure in the upper body.

Cushing's Syndrome: A rare endocrine disorder caused by excess cortisol production, which can lead to hypertension, among other symptoms. Missing this diagnosis could result in significant morbidity.
Hyperthyroidism: Excess thyroid hormone can cause increased blood pressure, and although less common as a cause of secondary hypertension, it's crucial not to miss due to its potential impact on the cardiovascular system.
Sleep Apnea: Although more common in older adults, sleep apnea can occur in young individuals and is associated with an increased risk of hypertension.

Thyroid Medullary Carcinoma: A rare type of thyroid cancer that can produce excess calcitonin, leading to hypertension.
Neurofibromatosis Type 1 (NF1): A genetic disorder that can cause renal artery stenosis or pheochromocytoma, leading to secondary hypertension.
Glucocorticoid-Remediable Aldosteronism: A rare genetic disorder causing excess aldosterone production, leading to hypertension.