28 September 2026
: Case report 
Coexisting Postural Orthostatic Tachycardia Syndrome on Autonomic Reflex Testing in Functional Neurologic Disorder
Unusual clinical course, Challenging differential diagnosis
Sushmita Das
AEF 1, Sri Rama Narayana Yerraballa AEF 1, Priyanka Shekhawat AEF 1*
DOI: 10.12659/AJCR.953323
Am J Case Rep 2026; 27:e953323
Table 2 Clinical timeline, diagnostic evaluation, and management highlighting the stepwise recognition of coexisting autonomic dysfunction in a patient with established functional neurological disorder (FND).
| Timepoint | Clinical events | Evaluation | Management | Interpretation |
|---|---|---|---|---|
| New daily persistent headaches, vertigo, episodic lower-extremity weakness, gait disturbance, drop attacks; onset of orthostatic symptoms | Brain MRI normal | Amitriptyline trial (ineffective) | Initial presentation: no structural neurologic disease identified | |
| Episodic orthostatic lightheadedness | Orthostatic vitals nonrevealing | Advised hydration, salt intake, positional measures | Limited sensitivity of bedside testing | |
| Fluctuating weakness and gait disturbance | Diagnosis of FND based on positive clinical signs and vEEG | Physical therapy with temporary improvement | FND diagnosis established | |
| Functional decline | Symptom exacerbation | |||
| Persistent orthostatic intolerance; wheelchair use due to symptoms; orthostatic symptoms reproduced in clinic | COMPASS-31 score 63.4 (markedly high); Beighton score: hEDS criteria met; autonomic reflex testing (tilt table): heart rate > 40 bpm without hypotension → POTS | Formal autonomic evaluation ordered and completed during the same period | Clear escalation trigger: persistent symptoms, risk factors, no improvement with lifestyle modifications.Objective confirmation of POTS | |
| Orthostatic intolerance and functional symptoms ongoing | Initiation of POTS-directed therapy (fluids, salt, compression, graded exercise), propranolol | Targeted physiologic treatment introduced | ||
| Functional gait impairment and psychogenic seizures | Re-initiation of physical therapy; referral to FND program | Multidisciplinary management | ||
| Improved orthostatic tolerance; reduced pre syncope; improved mobility | Clinical reassessment, COMPASS-31 score 30 | Continued therapy | Functional improvement temporally associated with diagnostic clarification and targeted management | |
| Abbreviations: COMPASS-31, Composite Autonomic Symptom Score-31; hEDS, hypermobile Ehlers-Danlos syndrome; MRI, magnetic resonance imaging; POTS, postural orthostatic tachycardia syndrome; vEEG, video electroencephalography. | ||||