The most accurate autonomic function test: the medical history

“Data! Data! Data! I can’t make bricks without clay” stated the famous detective Sherlock Holmes, a fictional character of the British writer, Sir Arthur Conan Doyle. It is true that data are needed to draw a proper conclusion. In patients with autonomic dysfunction, every symptom is a “clue” or “piece of data”, that must be precisely evaluated and interpreted by a well-trained eye. This is required in order to arrive at the correct solution of the case. Thus, the second paper of the series on Autonomic Function Tests by Goldstein and Cheshire, published in this issue of Clinical Autonomic Research, highlights the importance of the medical history, the most accurate autonomic function test [1, 2]. They also emphasize the need to rule out other disorders and to be certain that the patient truly has autonomic dysfunction.

Autonomic medicine is a relatively new and rapidly evolving field, and it has been under-recognized by the medical community. Therefore, it is crucial to educate multidisciplinary providers, as well as to support further research in this area. Hence, this paper is quite timely. The authors summarize the relevant and important steps required to perform a comprehensive autonomic medical history, which—let me reiterate—is the most important autonomic test [2]. It is crucial to query the patient’s account of daily activities and the chronology relating to the autonomic nervous system (ANS), and then to recognize that these symptoms may also fluctuate from day to day. The medical history should focus upon various aspects of autonomic disorders with regard to: Chief Complaint (the description by the patient for the reason of this evaluation); History of the Present Illness (history of the condition with chronology and patterns of autonomic symptoms, prior evaluations, including review of medical records, family observations); Past Medical History (past medical issues, including toxic exposures, chemotherapy, or Lyme disease); Family History (medical conditions of family members, especially those related to the patient’s current medical problems, such as neurologic, cardiac, endocrine, or genetic disorders (e.g., inherited synucleinopathies), and hyperflexibility syndromes, which are sometimes present in patients diagnosed with postural tachycardia syndrome (POTS); Current Medications, Dietary Supplements, and Herbal Remedies; Personal and Social History (living situation, daily functioning, disability, smoking, alcohol, substance abuse, past traumas and physical abuse, car accidents, stresses); and Review of Systems (with focus on specific components of the ANS). Goldstein and Cheshire also include less commonly recognized symptoms, such as: “water bottle sign”, “coat hanger pain”, shifting weight back and forth while standing, leg fidgeting while seated, physical deconditioning, and pretzel legs [2]. Olfactory dysfunction, visual hallucinations (a feature of dementia with Lewy bodies) and dream enactment behavior (rapid eye movement behavior disorder), visceral hypersensitivity or “somatic hypervigilance”, as described by Khurana [3], may point to specific disorders. The authors also highlight the importance of having an appropriately trained and experienced clinician who is knowledgeable in asking the correct questions and interpreting the subjective answers, with the ability to discriminate between the autonomic functions and non-autonomic aspects of different forms of dysautonomia as well as an awareness that patients may have other non-associated issues and incorrect interpretations of the connection between these and the autonomic disorders, which are often influenced by educational, ethnic, cultural and language backgrounds, and social media.

Goldstein and Cheshire also emphasize that it is crucial to determine the type of autonomic dysfunction (specific to the sympathetic noradrenergic, sympathetic cholinergic, and parasympathetic nervous systems) [2]. One must also realize that even within the subcategories of ANS, the symptoms can still be quite heterogenous.