Who is an Autonomic Specialist?
An autonomic specialist is a physician—typically a neurologist or cardiologist with specialized training in autonomic nervous system disorders—who evaluates and manages conditions like postural orthostatic tachycardia syndrome (POTS), neurogenic orthostatic hypotension, and other forms of dysautonomia. 1
Clinical Expertise and Training
Autonomic specialists are physicians who have expertise in diagnosing and treating autonomic nervous system dysfunction, with most being neurologists or cardiologists who have completed additional fellowship training or have developed specialized clinical interest in autonomic disorders 1, 2
These specialists perform and interpret autonomic reflex screen (ARS) batteries, which examine both sympathetic and parasympathetic function through tilt table testing, heart rate and blood pressure responses to Valsalva maneuver, deep breathing tests, quantitative sudomotor axon reflex testing, and beat-to-beat blood pressure measurements 3
The ACC/AHA/HRS guidelines note that "referral for autonomic evaluation can be useful to improve diagnostic and prognostic accuracy in selected patients with syncope and known or suspected neurodegenerative disease," though they acknowledge the scarcity of highly expert autonomic clinical centers 1
When to Refer to an Autonomic Specialist
For patients with benzodiazepine use history and orthostatic intolerance symptoms, referral to an autonomic specialist is indicated when:
There is a history of withdrawal seizures, unstable psychiatric comorbidities, unsuccessful office-based benzodiazepine tapering, or co-occurring substance use disorders 4
Patients have refractory gastrointestinal symptoms with orthostatic intolerance after exclusion of medication side effects and after appropriate lifestyle modifications (adequate hydration and physical exercise) have been attempted 1
Severe orthostatic intolerance symptoms persist, including lightheadedness, palpitations, tremor, generalized weakness, blurred vision, and fatigue, particularly when accompanied by orthostatic heart rate increase >30 bpm (or >120 bpm absolute) within 10 minutes of standing 4, 5
Critical Context for Benzodiazepine-Related Cases
Benzodiazepines are recognized confounders of POTS symptoms and autonomic dysregulation, and the AGA guidelines specifically note that medications, particularly centrally acting agents, may confound the presentation of orthostatic intolerance and autonomic dysfunction 4
The mechanistic basis of POTS association with medications like benzodiazepines may involve medication-induced autonomic dysregulation that resolves with time, meaning symptoms may be transient withdrawal phenomena rather than permanent POTS 4
Before referring to an autonomic specialist, the primary intervention should be to slow or pause the benzodiazepine taper until autonomic symptoms stabilize, as the American College of Physicians emphasizes that taper rate must be determined by patient tolerance to withdrawal symptoms 4
Diagnostic Capabilities
Autonomic specialists can perform basic autonomic testing including Valsalva maneuver, deep-breathing testing, ambulatory and home blood pressure monitoring when neurogenic orthostatic hypotension is suspected 1
Testing for POTS through postural vital signs (symptomatic increase in heart rate of 30 beats/min or more with 10 minutes of standing during an active stand or head-up tilt table test in the absence of orthostasis) should be considered, with referral to specialty practices in cardiology or neurology 1
The Valsalva, Respiratory and Orthostatic tests (30:15) are the gold standard methods for diagnosing cardiovascular autonomic neuropathy, and can be associated with RR Variability tests to increase sensitivity 2
Common Pitfalls to Avoid
Do not refer all patients with hypermobile Ehlers-Danlos syndrome or hypermobility spectrum disorders for autonomic testing—testing should be targeted only to those presenting with clinical manifestations of POTS, as universal testing is not supported by current evidence 1
The tilt table test should not be the test of choice for investigating cardiovascular autonomic neuropathy at an early stage, as it detects cases at more advanced stages; a tilt response with dysautonomic pattern (gradual drop in blood pressure without increasing heart rate) may suggest autonomic dysfunction 2
Recognize that autonomic specialists may also include allergy specialists or mast cell disease research centers when mast cell activation syndrome is suspected alongside autonomic dysfunction 1
Geographic and Resource Limitations
The U.S. writing committee for syncope guidelines carefully weighed the scarcity of highly expert autonomic clinical centers and the legal and resource implications, concluding they could not make more specific recommendations on autonomic testing beyond general guidance 1
This scarcity means that in many regions, patients may need to travel significant distances to access specialized autonomic evaluation, making appropriate patient selection for referral particularly important 1