From MedRevise
(Redirected from Low blood pressure)
Jump to navigation Jump to search
This man has a systolic blood pressure of 3mmHg. This is very low.


A systolic and diastolic blood pressure below around 90/50mmHg. The opposite of hypertension.

It can be varied, and generally the diagnostic line relies as much of symptoms as the exact value, since some people can be fine on 90/50, whereas others can have problems at 100/60.


Medical Emergency - Sustained, symptomatic low blood pressure will lead to shock which needs treating promptly!



Some people have long standing low blood pressure, other present develop it during emergencies. However, long term it is not really a huge risk, so people care about hypertension more...



There are three main causes of low blood pressure:

  • Cardiogenic - The heart isn't pumping enough blood around.
  • Vasodilation - The peripheral vessels have all dilated, meaning there is a much large space for blood in the body, and there isn't blood to go around.
  • Hypovolaemia - There's not enough blood going around

Clinical and Associated Features

The number one symptom is lightheadedness or dizziness. If its bad enough, people will faint or lose consciousness.

That is pretty much it. The other things you might experience will be from the cause, or from complications. So, if you go into shock, you will get reduced capillary refill time, tachycardia, shortness of breath.

Postural hypotension

A common symptom is postural hypotension, or orthostatic hypotension, where people get light headed on standing. It is diagnosed with a sitting standing blood pressure measurement. Get them to sit for five minutes, take a reading, get them to do one as soon as they stand up. Generally this is treated the same as hypotension.

Differential Diagnosis


Problematic sustained hypotension without a more sinister cause is very rare. Treat the cause, usually shock or iatragenic, and get on with your life!.