From the Guidelines
A diagnostic test cannot definitively differentiate between Postural Orthostatic Tachycardia Syndrome (POTS) and Chronic Fatigue Syndrome (CFS), also known as Myalgic Encephalomyelitis (ME), as these conditions require a comprehensive medical evaluation by healthcare professionals.
Diagnostic Approaches
For POTS, the primary diagnostic approach is a standing test or tilt table test, where heart rate and blood pressure are measured while lying down and then standing, as described in the 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope 1.
- A heart rate increase of 30+ beats per minute (40+ for those 12-19 years old) within 10 minutes of standing, without significant blood pressure drop, suggests POTS.
- Symptoms associated with POTS include those that occur with standing, such as lightheadedness, palpitations, and those not associated with particular postures, like bloating, nausea, and systemic symptoms, including fatigue and sleep disturbance. For CFS (now often called ME/CFS), diagnosis involves ruling out other conditions that cause fatigue and confirming symptoms like post-exertional malaise, unrefreshing sleep, cognitive impairment, and orthostatic intolerance that have persisted for at least 6 months, as outlined in the 2022 ACC expert consensus decision pathway on cardiovascular sequelae of COVID-19 in adults 1.
Co-Occurring Conditions
These conditions can coexist, with many ME/CFS patients showing orthostatic intolerance, and it's essential to consult with healthcare providers experienced in these conditions, typically cardiologists for POTS and neurologists or specialists in chronic fatigue for ME/CFS, as proper diagnosis requires professional assessment and often multiple tests to rule out other conditions.
Importance of Professional Evaluation
Given the complexity and overlap of symptoms between POTS and ME/CFS, a thorough medical evaluation is crucial for accurate diagnosis and management, as emphasized by the guidelines and expert consensus statements 1.
From the Research
Diagnostic Challenges
- Differentiating between Postural Orthostatic Tachycardia Syndrome (POTS) and Chronic Fatigue Syndrome (CFS), also known as Myalgic Encephalomyelitis (ME), or co-occurring conditions can be challenging due to overlapping symptoms and complex pathophysiology 2, 3.
- A diagnostic test that can accurately differentiate between these conditions is crucial for effective management and treatment.
Current Diagnostic Methods
- Tilt table testing is commonly used to diagnose POTS, but its sensitivity and specificity can be limited, especially in patients with ME/CFS 2, 4.
- A study found that abbreviated tilt table testing can miss a substantial proportion of patients with POTS, highlighting the need for more accurate and reliable diagnostic methods 2.
- Another study suggested that compression stockings can improve cardiac output and cerebral blood flow during tilt testing in ME/CFS patients, which may have implications for diagnostic testing 5.
Hemodynamic Responses
- Research has identified two different hemodynamic responses in ME/CFS patients with POTS during head-up tilt testing, suggesting that different pathophysiological mechanisms may be at play 4.
- The study found that patients with a limited heart rate increase during tilt testing had increased venous pooling, while those with a large heart rate increase had a hyperadrenergic response 4.
- These findings may have implications for the development of more targeted and effective diagnostic tests for POTS and ME/CFS.
Clinical Evaluation
- Clinical evaluation of patients with ME/CFS should include response to standing, as POTS is a frequent finding in this population 3.
- A study found that increasing fatigue was associated with an increase in heart rate, highlighting the importance of considering orthostatic intolerance in the diagnosis and management of ME/CFS 3.
- Further research is needed to determine the optimum intervention strategy to manage POTS in patients with ME/CFS 3.