hypotension
Table of Contents
hypotension
Introduction
- low blood pressure may be:
- transient unrelated to posture
- eg. SAH, initial PE embolism, vasovagal, in response to Valsalva (eg. micturition syncope), post-prandial, transient arrhythmia
- severe acute symptomatic persistent which can lead to the shocked patient, or be persistently lowish
- chronic persistent low BP
- for ADULTS
- a persistent systolic BP below 90mmHg or drops more than 40mmHg below their baseline, or a mean arterial pressure (MAP) below 65mmHg is highly suggestive of shock
- a person can be in shock with a normal BP if that BP is unable to maintain tissue perfusion
- healthy young adults can maintain their BP and heart rate much longer which can hide underlying shock state!
- check for evidence of shock: serum lactate, urine output, tachycardia, cold, clammy skin, pale lips, shallow rapid breathing, etc
- check for causes including less evident ones such as occult bleeding (eg. ruptured ectopic pregnancy), cold sepsis, PE
- a Shock Index (heart rate/systolic BP) > 0.7 suggests early shock and if > 1.0 suggests a shock state
Acute symptomatic hypotension
Chronic low blood pressure
- these patients may have BP 85-100mmHg but no tachycardia and no symptoms and many such patients are benign, especially in young women (see below)
- those who complain of “brain fog”, persistent fatigue, postural symptoms, etc should have further investigations including having their endocrine status checked (eg. TSH and perhaps cortisol workup)
- older patients with persistent low blood pressures appear to be at risk of increased cognitive decline even more so than those with hypertension and may be at higher risk of postural hypotension (orthostatic hypotension) complications such as falls
- these patients should have their medications reviewed, ECG to exclude bradycardia, etc, and their endocrine status checked (eg. TSH)
- they may require an echocardiogram to exclude a cardiac cause or chronic PE
Young adults with long standing, persistent low BP without tachycardia
- many young adults have a “benign” chronic BP around 90mmHg systolic which may be due to:
- petite women, or,
- being very fit
- sometimes persistent low BPs may reflect more important underlying issues and may not cause a supine tachycardia:
- iron deficiency anaemia, especially when associated with menorrhagia
- adrenal insufficiency
- hypothyroidism
- mild dehydration combined with oestrogen/progesterone status
- second trimester pregnancy
hypotension.txt · Last modified: 2026/06/24 06:45 by gary1