Orthostatic hypotension

Orthostatic hypotension is an independent predictor of mortality and the cause of significant morbidity associated with falls.

A common problem in frail older people. Orthostatic hypotension-related hospitalisations increase markedly with age.

Common causes include drugs (e.g., alpha-blockers, including tamsulosin [used for treating conditions such as benign prostatic hypertrophy], central sympatholytics, including tizanidine [used as a muscle relaxant], and diuretics), diseases causing peripheral neuropathy (e.g., diabetes mellitus), Parkinson's disease, and dementia with Lewy bodies.

Primary neurodegenerative disorders of the autonomic nervous system (pure autonomic failure, and multiple system atrophy or Shy-Drager syndrome) are less common, but cause severe orthostatic hypotension.

Acute or subacute onset should suggest an autoimmune or paraneoplastic disorder.

Treatment consists of addressing any underlying pathology, when possible, followed by discontinuing or reducing the dose of aggravating drugs, and non-pharmacological countermeasures (e.g., liberalisation of salt intake, use of abdominal binders or compression stockings). Volume expansion (using mineralocorticoid therapy), short-acting vasopressors, or noradrenaline (norepinephrine) precursor therapy with droxidopa are adjunctive therapies when non-pharmacological measures are insufficient.

Orthostatic hypotension is defined as a fall in systolic blood pressure of at least 20 mmHg (at least 30 mmHg in patients with hypertension) and/or a fall in diastolic blood pressure of at least 10 mmHg within 3 minutes of standing.[1]Freeman R, Wieling W, Axelrod FB, et al. Consensus statement on the definition of orthostatic hypotension, neurally mediated syncope and the postural tachycardia syndrome. Clin Auton Res. 2011 Apr;21(2):69-72. http://www.ncbi.nlm.nih.gov/pubmed/21431947?tool=bestpractice.com When orthostatic hypotension has an underlying neurogenic cause (e.g., peripheral neuropathy) it is associated with a blunted increase in heart rate, typically less than 15 bpm.[2]Norcliffe-Kaufmann L, Kaufmann H, Palma JA, et al. Orthostatic heart rate changes in patients with autonomic failure caused by neurodegenerative synucleinopathies. Ann Neurol. 2018 Mar;83(3):522-31. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5867255 http://www.ncbi.nlm.nih.gov/pubmed/29405350?tool=bestpractice.com Orthostatic hypotension becomes clinically significant if it is accompanied by symptoms of cerebral hypoperfusion, which can lead to syncope and falls.[3]Mol A, Bui Hoang PTS, Sharmin S, et al. Orthostatic hypotension and falls in older adults: a systematic review and meta-analysis. J Am Med Dir Assoc. 2019 May;20(5):589-97.e5. http://www.ncbi.nlm.nih.gov/pubmed/30583909?tool=bestpractice.com Orthostatic hypotension is associated with increased risk of dementia and cardiovascular disease, and is an independent risk factor for all-cause mortality.[4]Rawlings AM, Juraschek SP, Heiss G, et al. Association of orthostatic hypotension with incident dementia, stroke, and cognitive decline. Neurology. 2018 Aug 21;91(8):e759-68. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6107267 http://www.ncbi.nlm.nih.gov/pubmed/30045960?tool=bestpractice.com [5]Fagard RH, De Cort P. Orthostatic hypotension is a more robust predictor of cardiovascular events than nighttime reverse dipping in elderly. Hypertension. 2010 Jul;56(1):56-61. https://www.ahajournals.org/doi/10.1161/HYPERTENSIONAHA.110.151654?url_ver=Z39.88-2003&rfr_id=ori:rid:crossref.org&rfr_dat=cr_pub%20%200pubmed http://www.ncbi.nlm.nih.gov/pubmed/20458003?tool=bestpractice.com [6]Fedorowski A, Stavenow L, Hedblad B, et al. Orthostatic hypotension predicts all-cause mortality and coronary events in middle-aged individuals (The Malmo Preventive Project). Eur Heart J. 2010 Jan;31(1):85-91. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2800919 http://www.ncbi.nlm.nih.gov/pubmed/19696189?tool=bestpractice.com This topic concentrates on orthostatic hypotension caused by autonomic problems.