When POTS Phenotypes Flip: Why We Miss Hyperadrenergic States in Mixed Physiology
A case for longitudinal endocrine and immunological monitoring in POTS: masked adrenergic signaling, overlapping phenotypes, and the limits of snapshot-based diagnosis
Many clinicians believe that they understand Postural Orthostatic Tachycardia Syndrome (POTS).
Patients are sorted into subtypes. Hyperadrenergic, hypovolemic, and neuropathic states. The treatment follows the label. Salt, beta-blockers, vasoconstrictors, and volume expansion. Adjust as needed.
However, this framework assumes something that does not hold up under real-world physiology:
That phenotype is stable.
It isn’t.
POTS is not a static disorder. It is a dynamic, multisystem condition shaped by interactions between autonomic regulation, vascular tone, endocrine signaling, and immune activity. These systems do not operate independently, and they do not remain fixed. They shift with stress, hormonal changes, inflammation, procedures, and time.
When they shift, phenotypes don’t just overlap.
They reorganize.
This is where the current model fails.
We acknowledge “mixed POTS” in theory, but in practice, we still assign dominant labels based on what is most visible in a single snapshot: blood pressure, heart rate, and sometimes a catecholamine panel captured under one set of conditions.
From that, we infer the underlying physiology.
However, snapshot-based diagnosis misses one of the most important patterns in POTS:
Masked states.
Adrenergic signaling does not always present with the expected hemodynamic signature. Sympathetic activation can be buffered when vasodilation or low-volume physiology is present. The tachycardia is there, but blood pressure remains low. The clinical picture reads as hypotensive or hypovolemic, and adrenergic contribution is often dismissed.
Not because it is not present.
But because it isn’t dominant. Not yet.
Over time, this balance shifts, and volume status, hormonal signaling, and immune activity all move. The buffering effect disappears.
When it does, the phenotype appears to flip.
What emerges can look abrupt or paradoxical: rising blood pressure where there was previously hypotension and increased adrenergic symptoms where there was prior vascular collapse. In reality, the underlying physiology may have been present all along and masked by competing processes.
These transitions often cluster around hormonal shifts, which tend to create more barriers to recognition, not fewer.
This is the gap:
We don’t just misclassify POTS.
We miss when the underlying physiology changes.
When we miss this shift, treatment appears to be ineffective. Not because the disease is refractory, but because the physiology has evolved while the model of the patient has not.
Longitudinal thinking is essential in this context.
In addition to repeated vitals, tracking the evolution of autonomic, endocrine, and immune signals over time is important. Watching for inflection points. Recognizing when competing systems mask each other, and when that balance begins to shift.
This post introduces the concept of a longitudinal case study tracking a patient whose clinical presentation evolves over time, transitioning through mixed physiological states and ultimately revealing a phenotype shift that isolated snapshots often miss.
A case study that emphasizes genomic studies by providing functional context to the patient’s overall picture, moving beyond the search for one or two devastating variants causing pathology. Instead, it highlights the importance of polygenomic profiles that influence function and adaptation.
It is a case that only makes sense if you stop thinking in static categories and start tracking physiology as it actually behaves.