POTS And Orthostatic Intolerance In ME/CFS And Long Covid

Orthostatic intolerance is an umbrella term for conditions where symptoms occur when a person stands up. PoTS (Postural Orthostatic Tachycardia Syndrome) is a type of orthostatic intolerance which causes a sustained increase in heart rate. Most people with ME/CFS have some symptoms of orthostatic intolerance and it is often experienced by people with Long Covid, although it is often undiagnosed in both conditions.

This blog considers how people with ME/CFS and Long Covid are affected by PoTS, its symptoms, how it differs from other conditions that cause dizziness and how it is diagnosed.

1.   WHAT IS ORTHOSTATIC INTOLERANCE

Orthostatic intolerance (OI) refers to a condition in which symptoms worsen upon assuming an upright position, such as standing or sitting up.

Dizziness and the other symptoms of Orthostatic Intolerance occur because for a short period there is not enough blood flowing to the brain

Common OI symptoms include:

Symptoms are influenced or exacerbated by anything that diverts blood away from the brain, as detailed below:

2.   WHAT IS POSTURAL ORTHOSTATIC TACHYCARDIA SYNDROME (POTS)?

PoTS is a specific form of Orthostatic Intolerance and is defined by a sustained increase in heart rate:

• Heart rate increases by 30 beats per minute (bpm) or more in adults upon sitting up or standing (or by 40 bpm or more in adolescents (aged 12–19 years)

• The increase in heart rate occcurs within 10 minutes of standing, without a significant drop in blood pressure.

  
  

A study of 4835 patients with PoTS (Shaw, 2019) found the following :

• It occurs mostly in females (94%) of child-bearing age (15-50)

• Approximately 50% develop symptoms in adolescence

• Patients can present with a myriad of symptoms most commonly including light-headedness (99%), tachycardia (97%), presyncope or feeling faint (94%), headache (94%) and difficulty concentrating (94%)

•      Time to diagnosis - patients often have a lengthy delay before diagnosis

Symptoms of PoTS

Palpitations are a defining symptom in PoTS.  PoTS involves both cardiac and non-cardiac symptoms that arise when moving to a sitting up or standing position and affect daily function:

Cardiac:

• Light-headedness

• Tachycardia

• Chest pain

• Palpitations

• Shortness of breath

Non-cardiac:

• Brain fog

• Headaches

• Digestive issues (e.g., nausea, diarrhoea, bloating)

• Sleep disturbance

• Cold or discoloured extremities (acrocyanosis)

3.   POTS IN ME/CFS AND LONG COVID

ME/CFS

Most people with ME/CFS will experience some symptoms of Orthostatic Intolerance.  With regards to PoTS specifically, estimates of prevalence in ME/CFS range from 11–77%.

Long Covid

COVID-19 infection affects the autonomic nervous system and some people with Long Covid will experience Orthostatic intolerance of some kind. immune-mediated disruption to the autonomic nervous system may result in transient or long-term orthostatic intolerance syndromes. It is estimated that 2–14% may develop PoTS at around 6–8 months post-infection.

4.   COMMON CO-MORBIDITIES FOUND IN POTS

People who have PoTS may also suffer from other associated co-morbidities as detailed below:

5.   ORTHOSTATIC HYPOTENSION

Orthostatic hypotension (OH) is another form of orthostatic intolerance, but unlike PoTS, it involves a significant drop in blood pressure:

• A decrease of 20 mmHg (systolic) or more within 2–5 minutes of standing

Symptoms may include:

• Fainting or “blackouts”

• Light-headedness

• Vision changes

An example is micturition syncope, where men feel faint when rising to urinate, particularly at night. Sitting down during urination is recommended to prevent this.

6.   OTHER TYPES OF DIZZINESS IN ME/CFS AND LONG COVID

Dizziness in ME/CFS and Long Covid may not always be due to orthostatic intolerance or PoTS. Other causes may include:

• Meniere’s Disease: A disorder of the inner ear causing spinning sensations, hearing issues, and balance problems.

• PPPD (Persistent Postural Perceptual Dizziness): A vestibular condition where patients feel internal motion (rocking, swaying) even while still.

• Patients often describe feeling “as if drunk”, particularly in visually stimulating environments or even while lying down.

These conditions can overlap with PoTS, complicating diagnosis and treatment.

7.   NICE RECOMMENDATIONS ON MANAGING ORTHOSTATIC INTOLERANCE IN ME/CFS

The ME/CFS NICE Guideline which was published in October 2021 refers to Orthostatic Intolerance as a co-morbidity in ME/CFS, and it suggests management as follows:

Extract from NICE Guideline on ME/CFS: diagnosis and management 2021

8.   DIAGNOSIS

Unfortunately, a diagnosis of PoTS is often delayed for years. Diagnosis can be challenging as symptoms can be variable and tests are difficult to undertake.  Tests may include:

Active stand test or Tilt Table testing:

• Monitors heart rate and blood pressure during postural changes

• This should be done in the morning, without medications that affect heart rate or blood pressure

Halter monitoring:

• Rules out arrhythmias such as Supraventricular Tachycardia (SVT)

Blood tests to rule out other conditions, e.g

• Anaemia, thyroid dysfunction,  or deficiencies in vitamin B12, ferritin, Vitamin D

• Autoimmune markers if symptoms like dry eyes/mouth or rashes are present

• Mast cell activation (serum tryptase)

• Rare causes like adrenal tumours (urine catecholamines)

DIagnostic Criteria for PoTS

Criteria for diagnosing PoTS were drawn up in 2021 by the PoTS Working Group for the United States National Institutes for Health, and are shown below:

Defined by the POTS Working Group for the United States National Institutes of Health, 2021

9. MANAGING SYMPTOMS – DIET AND LIFESTYLE

There is no cure for PoTS, but symptoms can often be managed through diet and lifestyle approaches, a few of which are summarised below:

Fluid & Salt Intake:

• Increase fluids (2–3L/day) and dietary salt (unless contraindicated) to support blood volume.

Compression:

• Use waist-high compression garments to prevent blood pooling in the lower body.

Diet:

• Eat small, frequent meals; avoid high-carb or large meals which can divert blood to digestion and worsen symptoms.

Environment:

• Avoid standing in hot showers or prolonged upright posture.

• Morning symptoms are often worse due to overnight dehydration.

Physical activity:

• Start with recumbent or seated exercises, such as rowing or swimming, under guidance.

• Avoid overexertion, especially in ME/CFS or Long Covid patients with post-exertional malaise.

Medications:

Should be prescribed only by specialists in autonomic disorders. Some options include:

• Beta-blockers, fludrocortisone, midodrine

• Caution: some of these medications may worsen other ME/CFS symptoms

REFERENCES AND RESOURCES

Raj SR, Fedorowski A, Sheldon RS. Diagnosis and management of postural orthostatic tachycardia syndrome. CMAJ. 2022 Mar 14;194(10):E378-E385. doi: 10.1503/cmaj.211373. PMID: 35288409; PMCID: PMC8920526.

Vernino S, Bourne KM, Stiles LE, et al. Postural orthostatic tachycardia syndrome (POTS): state of the science and clinical care from a 2019 National Institutes of Health Expert Consensus Meeting — Part 1. Auton Neurosci 2021;235: 102828. https://pubmed.ncbi.nlm.nih.gov/34144933/

Shaw BH, et al. The face of postural tachycardia syndrome - insights from a large cross-sectional online community-based survey. J Intern Med. 2019 Oct;286(4):438-448. doi: 10.1111/joim.12895. Epub 2019 Apr 16. PMID: 30861229; PMCID: PMC6790699. https://pubmed.ncbi.nlm.nih.gov/30861229/

Lei LY, Chew DS, Sheldon RS, Raj SR. Evaluating and managing postural tachycardia syndrome. Cleve Clin J Med. 2019 May;86(5):333-344. doi: 10.3949/ccjm.86a.18002. PMID: 31066664 https://pubmed.ncbi.nlm.nih.gov/31066664/

Dani M, Autonomic dysfunction in 'long COVID': rationale, physiology and management strategies. Clin Med (Lond). 2021 Jan;21(1):e63-e67. doi: 10.7861/clinmed.2020-0896. Epub 2020 Nov 26. PMID: 33243837; PMCID: PMC7850225. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7850225/#:~:text=In%20orthostatic%20intolerance%2C%20the%20release,of%20'long%20COVID’).

Espinosa-Gonzalez, A. B et al 2023 Orthostatic tachycardia after covid-19. BMJ  https://doi.org/10.1136/bmj-2022-073488

Kavi, L 2022 Postural tachycardia syndrome and long COVID: an update British Jnl of General Practice  https://bjgp.org/content/72/714/8

#MEPedia: Postural Orthostatic Tachycardia Syndrome

https://me-pedia.org/wiki/Postural_orthostatic_tachycardia_syndrome#:~:text=POTS%20can%20be%20a%20co,from%2011%25%20to%2070%25.

PoTS UK – charity with useful resources including information for GPs:   https://www.potsuk.org/about-pots/what-is-pots/