SUN-261 - Orthostatic Hypertension: Hard to Recognize, Harder to Treat

Background

Orthostatic hypertension (OHT) lacks a universally accepted definition, but is commonly defined as an increase in systolic blood pressure (BP) of ≥ 20 mmHg or diastolic BP of ≥ 10 mmHg upon standing. Reported prevalence ranges from 5% to 30%, and is associated with multiple underlying conditions.

Case

A 63- year- old male with a history of class III obesity, liver cirrhosis, eosinophilic esophagitis, and chronic kidney disease stage 3a presented for evaluation of dizziness. Orthostatic vital signs revealed a supine BP of 120/70 mmHg, standing BP of 199/136 mmHg, and sitting BP of 158/96 mmHg. Diagnostic testing, including thyroid stimulating hormone, cortisol, aldosterone, renin levels, and tilt- table testing, were within normal limits. CT head, MRI head, and MRA brain showed no abnormalities.

Further testing showed elevated 24- hour urine studies, with a 5- hydroxyindoleacetic acid (5- HIAA) level of 13.0 mg/24h (normal < 6.0), vanillylmandelic (VMA) level of 6.6mg/24h (normal < 6.0), and normetanephrine level of 105 mcg/24h (normal 15- 100). Plasma dopamine levels were also elevated to 49 pg/mL (normal < 27). MRI of the adrenal glands showed no abnormalities. On follow up, the patient continued to experience episodic dizziness with elevated BP upon standing.

Discussion

The pathophysiology of OHT remains incompletely understood. Studies have observed that patients with OHT have an increase in plasma norepinephrine levels with standing, suggesting an excessive sympathetic activation and alpha- adrenoreceptor blockade. Prevalence increases with age, greater body mass index, and presence of essential hypertension and diabetes mellitus. Due to no standardized definition, evaluation and management strategies remain varied. Secondary causes, including pheochromocytoma or paraganglioma, must be excluded. Further research is needed to clarify the underlying mechanisms of OHT and to establish a uniform definition.

References

Jordan, J., Biaggioni, I., Kotsis, V. et al. Consensus statement on the definition of orthostatic hypertension endorsed by the American Autonomic Society and the Japanese Society of Hypertension. Clin Auton Res 33, 69–73 (2023). https://doi.org/10.1007/s10286-022-00897-8

Jordan J, Ricci F, Hoffmann F, Hamrefors V, & Fedorowski A. (2020). Orthostatic hypertension: Critical appraisal of an overlooked condition. Hypertension, 75(5), 1151–1158. https://doi.org/10.1161/HYPERTENSIONAHA.120.14340

Robertson, D. M. (2011). Orthostatic Hypertension. Hypertension, 57(2), 158–159. https://doi.org/10.1161/HYPERTENSIONAHA.110.163485

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