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Orthostatic hypotension, also known as postural hypotension, is a medical condition wherein a person's blood pressure drops when standing up or sitting down. The drop in blood pressure may be sudden, within 3 minutes or gradual. It is defined as a fall in systolic blood pressure of at least 20 mmHg or diastolic blood pressure of at least 10 mmHg when a person assumes a standing position. It occurs predominantly by delayed constriction of the lower body blood vessels, which is normally required to maintain adequate blood pressure when changing the position to standing. As a result, blood pools in the blood vessels of the legs for a longer period, and less is returned to the heart, thereby leading to a reduced cardiac output and inadequate blood flow to the brain.
Dysautonomia or autonomic dysfunction is a condition in which the autonomic nervous system (ANS) does not work properly. This may affect the functioning of the heart, bladder, intestines, sweat glands, pupils, and blood vessels. Dysautonomia has many causes, not all of which may be classified as neuropathic. A number of conditions can feature dysautonomia, such as Parkinson's disease, multiple system atrophy, and dementia with Lewy bodies, Ehlers-Danlos syndromes, autoimmune autonomic ganglionopathy and autonomic neuropathy, HIV/AIDS, autonomic failure, and postural orthostatic tachycardia syndrome.
Hypotension is low blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. Blood pressure is indicated by two numbers, the systolic blood pressure and the diastolic blood pressure, which are the maximum and minimum blood pressures, respectively. A systolic blood pressure of less than 90 millimeters of mercury or diastolic of less than 60 mm Hg is generally considered to be hypotension. Different numbers apply to children. However, in practice, blood pressure is considered too low only if noticeable symptoms are present.
Atenolol is a beta blocker medication primarily used to treat high blood pressure and heart-associated chest pain. Atenolol, however, does not seem to improve mortality in those with high blood pressure. Other uses include the prevention of migraines and treatment of certain irregular heart beats. It is taken by mouth or by injection into a vein. It can also be used with other blood pressure medications.
Reflex syncope is a brief loss of consciousness due to a neurologically induced drop in blood pressure and/ or a decrease in heart rate. Before an affected person passes out, there may be sweating, a decreased ability to see, or ringing in the ears. Occasionally, the person may twitch while unconscious. Complications of reflex syncope include injury due to a fall.
Orthostatic intolerance (OI) is the development of symptoms when standing upright that are relieved when reclining. There are many types of orthostatic intolerance. OI can be a subcategory of dysautonomia, a disorder of the autonomic nervous system occurring when an individual stands up. Some animal species with orthostatic blood pressure have evolved to cope with orthostatic disturbances.
Postural orthostatic tachycardia syndrome (POTS) is a condition in which a change from lying to standing causes an abnormally large increase in heart beat rate. This occurs with symptoms that may include lightheadedness, trouble thinking, blurred vision, or weakness. Other commonly associated conditions include Ehlers–Danlos syndrome, mast cell activation syndrome, irritable bowel syndrome, insomnia, chronic headaches, chronic fatigue syndrome, and fibromyalgia. It can be treated with lifestyle changes such as increasing fluid and salt intake, compression stockings, rising slowly after lying down, avoiding prolonged bedrest, and medication.
Reserpine is a drug that is used for the treatment of high blood pressure, usually in combination with a thiazide diuretic or vasodilator. Large clinical trials have shown that combined treatment with reserpine plus a thiazide diuretic reduces mortality of people with hypertension. Although the use of reserpine as a solo drug has declined since it was first approved by the FDA in 1955, the combined use of reserpine and a thiazide diuretic or vasodilator is still recommended in patients who do not achieve adequate lowering of blood pressure with first-line drug treatment alone. The reserpine-hydrochlorothiazide combo pill was the 17th most commonly prescribed of the 43 combination antihypertensive pills available In 2012.
Prazosin is an alpha-1 blocker medication primarily used to treat high blood pressure, symptoms of an enlarged prostate, and posttraumatic stress disorder (PTSD). It is a less preferred treatment of high blood pressure. Other uses may include heart failure and Raynaud syndrome. It is taken by mouth.
Midodrine is a vasopressor/antihypotensive agent. Midodrine was approved in the United States by the Food and Drug Administration (FDA) in 1996 for the treatment of dysautonomia and orthostatic hypotension. In August 2010, the FDA proposed withdrawing this approval because the manufacturer, Shire plc, failed to complete required studies after the medicine reached the market. In September 2010, the FDA reversed its decision to remove midodrine from the market and allowed it to remain available to patients while Shire plc collected further data regarding the efficacy and safety of the drug. Shire announced on September 22, 2011 that it was withdrawing completely from supplying midodrine and leaving it to several generics to supply the drug.
A tilt table test (TTT), occasionally called upright tilt testing (UTT), is a medical procedure often used to diagnose dysautonomia or syncope. Patients with symptoms of dizziness or lightheadedness, with or without a loss of consciousness (fainting), suspected to be associated with a drop in blood pressure or positional tachycardia are good candidates for this test.
Alpha-1 blockers constitute a variety of drugs that block the effect of catecholamines on alpha-1-adrenergic receptors. They are mainly used to treat benign prostatic hyperplasia (BPH), hypertension and post-traumatic stress disorder. Alpha-1 adrenergic receptors are present in vascular smooth muscle, the central nervous system, and other tissues. When alpha blockers bind to these receptors in vascular smooth muscle, they cause vasodilation.
Droxidopa is a synthetic amino acid precursor which acts as a prodrug to the neurotransmitter norepinephrine (noradrenaline). Unlike norepinephrine, droxidopa is capable of crossing the protective blood–brain barrier (BBB).
Alpha-blockers, also known as α-blockers or α-adrenoreceptor antagonists, are a class of pharmacological agents that act as antagonists on α-adrenergic receptors (α-adrenoceptors).
Orthostatic headache is a medical condition in which a person develops a headache while vertical and the headache is relieved when horizontal. Previously it was often misdiagnosed as different primary headache disorders such as migraine or tension headaches. Increasing awareness of the symptom and its causes has prevented delayed or missed diagnosis.
Dopamine beta (β)-hydroxylase deficiency is a condition involving inadequate dopamine beta-hydroxylase. It is characterized by increased amounts of serum dopamine and the absence of norepinephrine (NE) and epinephrine. Dopamine is released, as a false neurotransmitter, in place of norepinephrine. Other names for norepinephrine include noradrenaline (NA) and noradrenalin. This condition is also sometimes referred to as "norepinephrine deficiency". Researchers of disorders such as schizophrenia are interested in studying this disorder, as patients with these specific diseases can have an increase in the amount of dopamine in their system and yet do not show other symptoms of DβH deficiency.
A cerebrospinal fluid leak is a medical condition where the cerebrospinal fluid (CSF) surrounding the brain or spinal cord leaks out of one or more holes or tears in the dura mater. A cerebrospinal fluid leak can be either cranial or spinal, and these are two different disorders. A spinal CSF leak can be caused by one or more meningeal diverticula or CSF-venous fistulas not associated with an epidural leak.
Orthostatic syncope refers to syncope resulting from a postural decrease in blood pressure, termed orthostatic hypotension.
Orthostatic hypertension is a medical condition consisting of a sudden and abrupt increase in blood pressure (BP) when a person stands up. Orthostatic hypertension is diagnosed by a rise in systolic BP of 20 mmHg or more when standing. Orthostatic diastolic hypertension is a condition in which the diastolic BP raises to 98 mmHg or over in response to standing, but this definition currently lacks clear medical consensus, so is subject to change. Orthostatic hypertension involving the systolic BP is known as systolic orthostatic hypertension.
Renal sympathetic denervation (RSDN), is a minimally invasive, endovascular catheter based procedure using radiofrequency ablation or ultrasound ablation aimed at treating resistant hypertension. Nerves in the wall of the renal artery are ablated by applying radiofrequency pulses or ultrasound to the renal arteries. This causes reduction of sympathetic afferent and efferent activity to the kidney and blood pressure can be decreased. Early data from international clinical trials without sham controls was promising - demonstrating large blood pressure reductions in patients with treatment-resistant hypertension. However, in 2014 a prospective, single-blind, randomized, sham-controlled clinical trial failed to confirm a beneficial effect on blood pressure. A 2014 consensus statement from The Joint UK Societies did not recommend the use of renal denervation for treatment of resistant hypertension on current evidence. More recent sham-controlled trials suggest renal denervation can lead to lower systolic blood pressure.
References
- ↑ Naschitz, J E; Slobodin, G; Elias, N; Rosner, I (April 2006). "The patient with supine hypertension and orthostatic hypotension: a clinical dilemma". Postgraduate Medical Journal. 82 (966): 246–253. doi:10.1136/pgmj.2005.037457. PMC 2579630 . PMID 16597811.
- ↑ Jordan, Jens; Biaggioni, Italo (March 2002). "Diagnosis and treatment of supine hypertension in autonomic failure patients with orthostatic hypotension". The Journal of Clinical Hypertension. 4 (2): 139–145. doi:10.1111/j.1524-6175.2001.00516.x. PMID 11927799. S2CID 1205857.
- ↑ Biaggioni, Italo (12 October 2017). "Treatment of Supine Hypertension in Autonomic Failure - Full Text View - ClinicalTrials.gov". clinicaltrials.gov. United States: ClinicalTrials.gov, United States National Library of Medicine . Retrieved 2019-12-01.
- ↑ Naschitz, J. E.; Slobodin, G.; Elias, N.; Rosner, I. (2006). "The patient with supine hypertension and orthostatic hypotension: A clinical dilemma". Postgraduate Medical Journal. 82 (966): 246–253. doi:10.1136/pgmj.2005.037457. PMC 2579630 . PMID 16597811.
- ↑ Chen, Jack J.; Han, Yi; Tang, Jonathan; Portillo, Ivan; Hauser, Robert A.; Dashtipour, Khashayar (2018). "Standing and Supine Blood Pressure Outcomes Associated with Droxidopa and Midodrine in Patients with Neurogenic Orthostatic Hypotension: A Bayesian Meta-analysis and Mixed Treatment Comparison of Randomized Trials". Annals of Pharmacotherapy. 52 (12): 1182–1194. doi:10.1177/1060028018786954. PMID 29972032. S2CID 49674644.
- ↑ Jordan, Jens; Fanciulli, Alessandra; Tank, Jens; Calandra-Buonaura, Giovanna; Cheshire, William P.; Cortelli, Pietro; Eschlboeck, Sabine; Grassi, Guido; Hilz, Max J. (August 2019). "Management of supine hypertension in patients with neurogenic orthostatic hypotension: scientific statement of the American Autonomic Society, European Federation of Autonomic Societies, and the European Society of Hypertension". Journal of Hypertension. Wolters Kluwer. 37 (8): 1541–1546. doi:10.1097/HJH.0000000000002078. PMID 30882602. S2CID 81988272 . Retrieved 2019-12-01.
