Surgery has also been linked to pancreatitis in dogs, probably due to low blood pressure or low blood volume caused by anesthesia. (whole-dog-journal.com)
To better describe the pathophysicology of POTS, it can be grouped in various ways, such as primary (unknown cause) and secondary (caused by something else) POTS, hypovolemic POTS (associated with low blood volume), partial dysautonomic POTS (associated with a partial autonomic neuropathy), and hyperadrenergic POTS (associated with high levels of norepinephrine). (drlam.com)
Iron deficiency causes symptoms such as low blood volume, fatigue, shortness of breath, dizziness, headaches, pale skin and weakness (48). (healthline.com)