Driving Therapy Forward

Gary Murray, Rohit Arora and Robert Bulgarelli take a look at ANS dysfunction and some of the therapies available.

The autonomic nervous system (ANS) helps to control and coordinate all bodily functions to maintain homeostasis. The ANS, through the parasympathetics (P) and sympathetics (S), performs this work largely unnoticed. By the time it is noticed, due to symptoms presenting, it is typically late in the disease or disorder progression and physicians are left with few therapy options. Early identification of ANS dysfunction enables early and more therapy options and is associated with improved outcomes. Driving therapy, by balancing P and S and, in turn, helping to normalize many other clinical measures, can stabilize a patient, reduce co-morbidities, and permit the physician to be more aggressive with the primary condition.

A simple, yet common condition that exemplifies this is the depressed hypertensive (D-HTN). According to the CDC, hypertension (HTN) and depression are among the five most common diseases in the US. A CDC report indicates that 26.7% of the adult US population are hypertensive, resulting in 44.7 million office-based physician visits annually [Health, United States, 2007. NCHS]. From the same report, 16% of the US adult population are depressed resulting in 21.0 million office visits. Although the number of D-HTNs is currently unknown, an estimate of 20% (approximately 16 million adults) of the adult HTN population is thought to be a reasonable, conservative estimate.

Excess P activity is associated with depression. Excess S activity is associated with HTN. D-HTN, therefore is an autonomic and clinical conundrum. Autonomically, D-HTN suggests that P and S are both high. Technically, observing D-HTN requires observing both P and S independently and simultaneously. To do so, non-invasively, requires that analysis of respiratory activity be included concurrent with the autonomic signal processing. Clinically, anti-depressants can raise BP, exacerbating HTN and anti-hypertensives can raise P activity, exacerbating depression. Autonomic monitoring can help to direct therapy to restore balance between the P and S, and in turn enable treatment of the remaining disorder to be pursued more aggressively.

ANS-guided therapy for restoration of balance between P and S is based on commonly prescribed medications, including anti-hypertensives and beta-blockers for S-blockade, anti-depressants for P-blockade, and vasopressors for S-stimulation. Of course, the specific category and specific agent selected would depend on the specific history of the individual patient.

Heart disease, chronic pain, diabetes, sleep disorders, Parkinson’s disease, COPD, and many chronic diseases carry the risk of HTN, depression and other co-morbidities. The co-morbidities can include GI upset, sleep difficulties, frequent headache or migraine, orthostasis, anxiety and poor circulation. All of these co-morbidities can involve the ANS. ANS testing and ANS-guided therapies to establish and maintain balance between P and S can minimize these co-morbidities, potentially minimizing amounts and numbers of medications, reducing healthcare costs, and improving patient outcomes.