Pathological Etiology:

1. Pathophysiological Factors:

● Neurological/Pain-Related

○ Autonomic Neuropathies

○ Hyperadrenergic POTS

○ Peripheral Neuropathy

● Blood Volume-Related

○ Thoracic Hypovolemia

○ Diminished Venoconstriction

● Muscular dysfunction

○ Muscle Pump Dysfunction

○ Reduced Cardiac Output

2. Immune/Inflammatory-Related

● Autoimmune Responses

● Inflammatory Mechanisms

● Mast Cell Activation Disorders

● Molecular Mimicry (e.g., post-HPV vaccination)

3. Connective Tissue Integrity:

● Connective Tissue-Related

○ EDS

4. Endocrine Factors:

● Endocrine Dysfunction

● Decreased Norepinephrine Clearance

5. Genetic/Hereditary:

● Genetic/Hereditary Predisposition

6. Iatrogenic:

● Medication-Induced

7. Pregnancy

Non-Physiological Etiology:

1. Idiopathic POTS

2. Deconditioning

3. Psychological or Behavioral POTS

● Anxiety/stress