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Hypotension

Category: Illness or disabilities

Type

Involuntary

Introduction and description

Hypotension is 'abnormally' low blood pressure especially in the arteries of the systemic circulation.  It is a symptom,  rather than a disease.  And in most cases requires no medical intervention.

It is the opposite of hypertension, which is high blood pressure. Blood pressure is the force of blood pushing against the walls of the arteries as the heart pumps out blood. If it is lower than normal then it is called low blood pressure or hypotension.

Hypotension is generally considered as systolic blood pressure less than 90 millimeters of mercury (mm Hg) or diastolic less than 60 mm Hg. However in practice, blood pressure is considered  'low' only if noticeable symptoms are present.

  • Orthostatic hypotension or postural hypotension, orthostasis, and colloquially as head rush or dizzy spell, is a form of hypotension in which a person's blood pressure suddenly falls when the person stands up or stretches. The decrease is typically greater than 20/10 mm Hg and may be most pronounced after resting. The incidence increases with age.
  • Postprandial hypotension is a drastic decline in blood pressure which occurs 30–75 minutes after eating substantial meals. When a great deal of blood is diverted to the intestines  to facilitate digestion and absorption, the body must increase cardiac output and peripheral vasoconstriction in order to maintain enough blood pressure to perfuse vital organs, such as the brain.

It is true that, for some people who exercise and are in top physical condition, low blood pressure can be a sign of good health and fitness.  

Symptoms

For some people, low blood pressure can cause dizziness and fainting.

Symptoms associated with orthostatic hypotension in pure autonomic failure and multiple system atrophy - Mathias CJ, Mallipeddi R, Bleasdale-Barr K; Neurovascular Medicine Unit, Division of Neurosience and Psychological Medicine, Imperial College School of Medicine at St Mary's Hospital, Praed Street, London
The symptoms caused by or relating to orthostatic hypotension (over 20 mmHg systolic blood pressure) were evaluated using a questionnaire in 72 patients with primary chronic autonomic failure, 32 of whom had pure autonomic failure (PAF, and 40 multiple system atrophy (MSA).
The most common posturally related symptoms were dizziness (84% PAF, 83% MSA), syncope (91% PAF, 45% MSA), visual disturbances (75% PAF, 53% MSA) and suboccipital/paracervical 'coat-hanger' neck pain (8 l% PAF, 53% MSA). Chest pain occurred mainly in patients with PAF (44% PAF, 13% MSA). Improvement occurred with sitting or lying flat. Non-specific symptoms (weakness, lethargy and fatigue) were common in both groups…. .
PMID: 10552235

Many of the symptoms, however, depend on the cause of the low blood pressure and these can be many.  One of the symptoms is that it causes hallucinations and visions.

Causes

Low blood pressure can be due to:

Low blood volume

Reduced blood volume, called hypovolemia, is one  mechanism producing hypotension. This can result from haemorrhage, or blood loss; insufficient fluid intake, as in starvation; or excessive fluid losses from diarrhoea or vomiting.

Anaphylaxis

 It can also be caused by anaphylatic shock or anaphylaxis…..

Cardiovascular aspects of anaphylaxis: implications for treatment and diagnosis -Brown SG ;  Discipline of Emergency Medicine, The University of Western Australia at Fremantle Hospital, Fremantle, Western Australia, Australia.
………….Nausea, vomiting, incontinence, diaphoresis, dyspnoea, hypoxia, dizziness and collapse are associated with hypotension. Relative bradycardia (falling heart rate despite hypotension) is a consistent feature of hypotensive insect sting anaphylaxis and may represent a non-specific physiological response to severe hypovolaemia in conscious individuals.

Shock

When anyone suffers from a shock of any sort – psychological or physical – their blood pressure drops.  This usually has the effect of them either lying down [good!] or falling down [not good!]; and they rest. 

If the blood pressure is so low as to make them dizzy, with a bit of luck they may also go to sleep.  Thus hypotension is the way the body forces the person to rest after any form of trauma, in order that the autonomic system can take over and repair the damage.  Thus to ‘treat’ hypotension may actually be entirely unproductive.  It may be far better to get the person comfortably lying down in a quiet, low lit warm safe place, so they can sleep and recover

Current prehospital traumatic brain injury guidelines use a systolic blood pressure threshold of less than 90 mm Hg for treating hypotension for individuals 10 years and older based on studies showing higher mortality when blood pressure drops below this level. However, the guidelines also acknowledge the weakness of the supporting evidence. …. Conclusions and findings:  ….[Our study found] there is no identifiable threshold or inflection point between 40 and 119 mm Hg. Thus, in patients with traumatic brain injury, the concept that 90 mm Hg represents a unique or important physiological cut point may be wrong. Furthermore, clinically meaningful hypotension may not be as low as current guidelines suggest. PMID:  27926759

There even seems to be some tentative evidence that if you already have low blood pressure, your chance of survival in case of accident or injury is a great deal better

Patients with isolated hypotension required less early critical resources (14% vs. 52%), had less serious injury (20% vs. 61%), and had lower mortality (24 hours, 1% vs. 26%; in-hospital, 3% vs. 34%). PMID:  25757121

 

Pharmaceuticals

Pharmaceuticals are widely implicated in causing hypotension.  The main reason is that numerous drugs are treated as a poison by the body, as such the person is in effect suffering from poisoning with all its related symptoms.  The symptom of hypotension may be as a result of a prescribed dose or an overdose, deliberate or otherwise.  For example:

Oxetorone is a serotonin antagonist antimigraine drug ….. The aim of this study is to describe the toxicological profile of oxetorone [using] retrospective and observational study of cases exposure to oxetorone, reported to the Angers Poison and Toxicovigilance Centre between January 2002 and May 2016. …..We included 43 cases of exposure, …. Symptoms of moderate severity (PSS2 = drowsiness, hypertonia, myosis, convulsions, arterial hypotension, QRS widening, QTc prolongation) were observed following ingestion of more than 600 mg of oxetorone …. and severe symptoms (PSS 3 = coma, convulsions, QTc prolongation, QRS widening, ventricular tachycardia, arterial hypotension, cardiogenic shock) were observed starting from 1800 mg PMID:  27967233

There is a correlation between anaesthetics and hypotension, of which the majority of anaesthetists are aware, thus there is the possibility that the many cases of hallucinations, out of body experiences and near death experiences that appear to be caused by being anaesthetised, may be being caused by hypotension

Most anesthesia providers prefer to do a subarachnoid block (SAB) for cesarean section because of its rapid onset and reliability to provide adequate anesthesia. However an effect of the SAB is that it causes a spinal-induced hypotension (SIH) in up to 85% of the population. PMID:  27935779

 The eHealthme site collects Adverse Drug Reports from doctors in the USA, submitted to SEDA and the FDA. 

 

In order to see which drugs are implicated in causing hypotension please follow this LINK.  Note that we have been having trouble with broken links from this site, so if the link does not work, use the 'conditions' box to find the symptom.  Now scroll down and find the section 'Drugs that could  cause'.  This is a dynamically updated list.  As of December 2016 over 3,000 drugs were capable of causing hypotension.

It would seem that practically all classes of drug can have this result, which is a poor reflection on drugs and on prescribing practise, given that it is clear that these drugs are causing shock to a bodily system already under attack. 

Hypovolemia, for example, can be induced by excessive use of diuretics, and Beta blockers can cause hypotension both by slowing the heart rate and by decreasing the pumping ability of the heart muscle.  Excessive vasodilation leading to hypotension can also result from medications such as  calcium channel blockers, angiotensin II receptor blockers -  ACE inhibitors. Many anaesthetic agents and techniques, including spinal anesthesia and most inhalational agents, produce significant vasodilation.

Pathogens

Hypotension can be a symptom of severe pathogen attack – in which case the symptom is serious and the pathogen needs to be identified quickly.

When anyone suffers from severe pathogen attack – viruses, bacteria, fungi, toxin, parasite or similar – for example radiation or ‘bad gases’ - their blood pressure drops.  Just like shock, this usually has the effect of them either lying down [good!] or falling down [not good!]; and they rest, or better still sleep.  If it is truly severe they go into a coma, which is simply a much deeper form of sleep.  Hypotension thus forces the person to rest after any form of pathogen attack, in order that the autonomic system can take over and repair the damage.  Thus to ‘treat’ hypotension is entirely unproductive.  It could kill them.

This prospective cohort study was carried out in the emergency department at an academic medical center. A total of 51 patients met enrolment criteria during the study period and 41 of them were included in the study. Inclusion criteria were patients 18 years old or older, diagnosed to have either sepsis-induced hypotension or septic shock…….  RESULTS: 61% were diagnosed to have sepsis-induced hypotension and 39% were diagnosed with septic shock. …. [there was]  no significant correlation between the physiological parameters and the 30-day mortality. PMID:  23082413

On other words, ignore the hypotension and hunt the pathogen causing the sepsis.  In the meantime, get the person comfortably lying down in a quiet, low lit, warm, safe place, so they can sleep and sleep and sleep.

Nutritional deprivation

Without the necessary nutrients – vitamins, amino-acids, minerals, fatty acids, carbohydrates and so on the body does not have the fuel it needs to keep the heart pumping normally and at the right pressure.  Anorexics, the starving, the bulimics all suffer from low blood pressure, fatigue, reduced drive, dizziness, and cold limbs. Additionally, deficits in attention and memory are quite likely.

Old age and fragility

As people age, their blood vessels and organs become more fragile, their skin thinner, and their heart weaker.  In order not to put too much pressure on the heart, blood vessels and so on, the body naturally lowers the blood pressure so that the person does not haemorrhage or suffer heart failure. 

The consequences of this, is the person has to be much more careful getting up in the morning after sleeping, or getting up from a chair, for example, every movement must be much slower and more deliberate to give the body time to adjust the pressure so the person doesn’t lose consciousness and fall.

Many old people fall because they temporarily lose consciousness after too rapid a movement, or too energetic a movement, when their blood pressure is low.  THIS DOES NOT NEED TREATMENT, the body is doing a good job in protecting ever more fragile parts, all that is needed is an understanding that everything needs to be taken far more slowly and a handhold must be around the whole time – something to hang onto until everything has adjusted itself again.

As someone once said to me, the elderly need to treat the things in their house like a rock-climber treats the cliff face – never let go!

Meditation, sleeping and other relaxation methods

 

Many methods of relaxation are specifically designed to invoke the parasympathetic nervous system.  It is normal when we are relaxed or lying down and inactive, or are meditating deeply, to have low blood pressure, sometimes in the practised meditator the blood pressure is very low.  That is why these methods are used to lower blood pressure in those with hypertension.  But, one has to be aware that one cannot suddenly leap up after deeply resting or meditating, as it is more than likely that it will shock the heart, put a stress on it and you may well fall over, because the blood pressure must be allowed to rise again normally.

This is why it is exceptionally dangerous to suddenly disturb people in deep trance conditions, for example, or under hypnosis, it puts a great strain on their heart and is very dangerous.  They have to be allowed to recover slowly. 

Wikipedia
Orthostatic hypotension is characterised by symptoms that occur after standing (from lying or sitting), particularly when this is done rapidly. Many report lightheadedness (a feeling that one might be about to faint), sometimes severe. Generalized weakness or tiredness may also occur. Some also report difficulty concentrating, blurred vision, tremulousness, vertigo, anxiety, palpitations (awareness of the heartbeat), feeling sweaty or clammy, and sometimes nausea. A person may look pale.

Take it slow.

Treatment

As long as the person is allowed to lie down rest and sleep in a safe, warm, quiet comfortable place, hypotension, unless it is caused by such things as nutritional deprivation, requires no treatment.

For reasons which are unclear, the medical profession believe that hypotension needs to be treated with antihypotensive agents, also known as a vasopressor agents, pharmaceuticals that raise blood pressure.  These have an extremely unenviable record in terms of safety.  For example in premature babies use of these drugs has caused haemorrhage and death.  This is because the body has lowered the blood pressure to that which the very delicate heart and vessels of the premature baby can stand, if the pressure is raised, the heart and blood vessels fail:

In the premature neonate, there is no consensus regarding normal blood pressure (BP). The most common definition used is a mean arterial BP (MAP) less than the gestational age (GA); however, studies indicate that the neuroprotective mechanism of autoregulation is lost below a MAP of 30 mm Hg…… To determine whether hypotension defined as MAP <30 mm Hg or MAP less than the infant's GA better predicts adverse outcomes of intraventricular hemorrhage (IVH) and death.  CONCLUSIONS:   Neither definition of hypotension independently predicts adverse outcome in multivariate logistic regression. Vasopressor therapy, however, is an independent predictor of IVH and death in premature infants.  PMID:  27898415

 the body is a truly wonderful thing and we must let nature take its course.

How it works

Why do people get hallucinations, out of body experiences, even near death experiences from hypotension?  Severely low blood pressure can deprive the brain and other vital organs of oxygen and nutrients - hypoxia.

References and further reading

NOTE
An exceptionally important section that is pertinent to this section is that on Anaphylaxis.  The reason will become clear if one follows the LINK.  The description uses the work of the Nobel prize winner Dr Charles Richet

see also Blood circulatory system diseases

  • Clin Toxicol (Phila). 2016 Dec 14:1-5. [Epub ahead of print] New evidence for oxetorone toxicity. Deguigne M1, Bruneau C1, Touré A1, Turcant A2, Le Roux G1.
  • Ann Behav Med. 2016 Dec 12. [Epub ahead of print] Autonomic Cardiovascular Control and Executive Function in Chronic Hypotension. Duschek S1, Hoffmann A2, Reyes Del Paso GA3, Ettinger U4.  PMID: 27957701
  • Annu Rev Nurs Res. 2017 Jan;35(1):159-178.  Treatment and Prevention of Spinal-Induced Hypotension in the Cesarean Section Patient: What Does the Evidence Say?  Pellegrini JE.
  • JAMA Surg. 2016 Dec 7. doi: 10.1001/jamasurg.2016.4686. [Epub ahead of print]  Mortality and Prehospital Blood Pressure in Patients With Major Traumatic Brain Injury: Implications for the Hypotension Threshold. Spaite DW1, Hu C2, Bobrow BJ3, Chikani V4, Sherrill D5, Barnhart B6, Gaither JB1, Denninghoff KR1, Viscusi C1, Mullins T7, Adelson PD8.
  • Zh Nevrol Psikhiatr Im S S Korsakova. 2016;116(6 Vyp 2. Neurology and psychiatry of elderly):54-59. [Orthostatic hypotension in dementia with Lewy bodies].  [Article in Russian]  Chimagomedova AS1, Levin OS1.  1Russian Medical Academy of Postgraduate Education, Moscow, Russia.  PMID:  27905360
  • Neonatology. 2016 Nov 30;111(3):228-233. [Epub ahead of print]  Hypotension and Adverse Outcomes in Prematurity: Comparing Definitions.  St Peter D1, Gandy C, Hoffman SB.
  • Med J Malaysia. 2012 Jun;67(3):259-64.  The use of laboratory and physiological parameters in predicting mortality in sepsis induced hypotension and septic shock patients attending the emergency department.  Hisamuddin NA1, Azlan K.

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