A Challenging Case of Secondary Hyperparathyroidism From Hypovitaminosis D in a Young Man With Hypertensive Crisis and Target Organ Damage.

Hypertension is a common global condition, with most cases being primary and a minority arising from secondary causes, often endocrine in origin. Young patients presenting with hypertensive crises are more likely to have secondary aetiologies, necessitating a systematic and comprehensive workup. This case report describes a 37-year-old man presenting with severe headache, visual disturbances, and chest pain, with a blood pressure of 250/170 mmHg. Evaluation revealed advanced retinopathy, cerebral microhaemorrhages, renal impairment, and left ventricular hypertrophy, consistent with target organ damage. Further investigations identified secondary hyperparathyroidism due to profound hypovitaminosis D as the likely cause. Targeted treatment corrected the vitamin D deficiency and hypocalcaemia while gradually controlling blood pressure, leading to a favourable outcome. This exceptionally rare presentation underscores the need for wide-ranging diagnostic assessment in young patients with hypertensive crises, as identifying reversible secondary causes can significantly influence prognosis and long-term morbidity.