The Unusual Culprit: Vitamin D Deficiency as a Rare Cause of Resistant Hypertension

Resistant hypertension is defined as blood pressure that remains above target despite the use of three antihypertensive agents of different classes, including a diuretic. While essential hypertension is the most common diagnosis, secondary causes must be rigorously investigated. This case report highlights a 26 year old female presenting with hypertensive emergency and subsequent resistant hypertension. Extensive workup ruled out common secondary causes but revealed severe Vitamin D deficiency and associated secondary hyperparathyroidism. Following Vitamin D supplementation and normalization of levels, the patient's blood pressure was successfully controlled with a reduced drug regimen. This case suggests that Vitamin D deficiency, via its role in the Renin-Angiotensin-Aldosterone System (RAAS) and parathyroid hormone regulation, can be a treatable contributor to resistant hypertension.