Orthostatic Intolerance (OI)

What is orthostatic intolerance (OI)

There are a range of definitions that can assist with defining Orthostatic Intolerance (OI):

• orthostatic = an upright posture, either sitting or standing
• tachycardia = fast heart rate
• hypotension = low blood pressure
• autonomic nervous system = Your autonomic nervous system controls all of your body functions you don’t need to think about, such as heart rate, blood pressure, breathing and digesting.

Additionally, there are a number of different forms of orthostatic intolerance, these are

• Postural Orthostatic Tachycardia Syndrome (POTS)
• Orthostatic hypotension (OH)
• Neurally mediated hypotension (NHH).

How are ME/CFS and orthostatic intolerance (OI) connected?

Orthostatic intolerance is common in people with ME/CFS and can contribute significantly to the level of disability experienced. There is growing awareness that orthostatic stress may also contribute to post-exertional malaise (PEM).

There are many causes of orthostatic intolerance. It is important you work with your doctor to find out if ME/CFS is the cause for you.

Sometimes when undergoing testing for OI, results may be returned as “normal”. However, if you experience problems with sitting and standing, you may have orthostatic intolerance. Research suggests people with ME/CFS have a 25% decrease in blood flow to the brain on sitting or standing, even when their blood pressure and heart rate measurements are normal

Emerge Australia supports people living with ME/CFS who may have a co-diagnosis of orthostatic intolerance. If you have received a primary diagnosis of orthostatic intolerance in any of its forms, Dysautonomia International has a wealth of resources, knowledge and support for your diagnosis.

Symptoms and treatment of orthostatic intolerance (OI)

When you stand up, gravity causes an increase in blood to the lower part of your body. In in a healthy person, your autonomic nervous system regulates blood flow very quickly, and you experience no symptoms. In someone with OI, the autonomic nervous system has problems adjusting. This means that there is a decrease in blood flow to other areas of the body.

• lightheaded or dizzy when sitting or standing
• intolerance to heat and/or cold
• trouble concentrating
• word finding problems
• nausea
• feeling shaky
• fatigue
• headache
• heart palpitations.

Often, these symptoms become less or go away completely when you sit or lie down again.

What is the 10-Minute NASA Lean Test and diagnosis of orthostatic intolereance (OI)?

The 10-Minute NASA Lean Test is a simple test used to check for orthostatic intolerance. Orthostatic intolerance is when symptoms happen after standing up, such as dizziness, nausea, or feeling faint.

What happens during the test?

1. You will first lie quietly on your back for a short time.
2. You will then stand and lean back against a wall for up to 10 minutes.
3. During the test, a doctor or nurse will check your: Heart rate, blood pressure, symptoms
4. After the test, the doctor will review the results and decide what to do next.

What happens after the test?

Depending on your results and your doctor’s experience, they may:

• Tell you the test did not show signs of orthostatic intolerance.
• Diagnose orthostatic intolerance and refer you to a specialist, such as a cardiologist or neurologist, for further testing or treatment.
• If you are referred, try to see someone who has experience treating orthostatic intolerance.
• Suggest treatments to help improve blood flow and manage symptoms.

Treatment and Management Strategies

There are many different causes of orthostatic intolerance. Treatment and management will depend on the underlying cause. When it is not possible to find the underlying cause, treatment focusses on managing symptoms.

Treatments can be divided into two types, lifestyle management and medication. All treatments should be in consultation with your treating doctor, who knows your medical history and can determine if they are safe for you.

Lifestyle management strategies

• a high salt diet
• adequate fluids
• compression garments – these should be fitted correctly
• exercise – Exercise is not usually considered safe for people with ME/CFS.
• Preventing post-exertional malaise should come before any attempt at exercise.
• mobility aids such as walking sticks or wheelchairs
  use a shower seat as hot water can make the symptoms feel worse.

Medication management strategies

There is no “one size fits all” approach to medication. You will need to discuss with your doctor the potential risks and benefits, including other medical conditions such as allergies.

With the right approach and management plan, you can ease some of the disability associated with orthostatic intolerance, which will improve your quality of life.

Learn more with Emerge Australia and the Bateman Horne Center

Emerge Australia offers a free education course that covers:

• How orthostatic intolerance is diagnosed
• What the 10-Minute NASA Lean Test is
• What happens after the test
• How to talk to your doctor about orthostatic intolerance and prepare for your medical appointment
• How to manage symptoms by pacing upright activities.

 Resources  

• Symptom Severity Hierarchy   
• Sleep and Pain Profile 
• NASA Lean Test for orthostatic intolerance (OI)  
• World Health Organization Disability Assessment Schedule 2.0 (WHODAS).