Vasovagal Syncope After Cervical Nerve Treatment

A 41-year-old woman with a complex history of cervical pain, vertigo, and tinnitus experienced a rare but significant delayed reaction after a pain-relief procedure. Approximately 20 hours after undergoing pulsed radiofrequency treatment on nerves in her neck and head, she developed a sudden drop in consciousness consistent with a vasovagal syncope event. The case, documented by researchers Kurnia Hendra Wijaya and Buyung Hartiyo Laksono, highlights a previously underreported risk for a procedure that otherwise successfully treated several of her symptoms.

### A Procedure for Complex, Chronic Pain

The patient presented with a challenging combination of chronic conditions: cervical radiculopathy from a herniated disc, tension-type headaches, a history of cluster headaches, chronic spontaneous vertigo, and tinnitus. Her newly diagnosed hypertension added another layer of complexity. Pulsed radiofrequency (PRF) was selected as a minimally invasive neuromodulation technique. Under fluoroscopic guidance, doctors applied PRF to the bilateral greater and lesser occipital nerves and the C3 and C4 dorsal root ganglia. The goal was to disrupt pain signals from these specific nerves without causing permanent damage. The procedure itself, performed under light sedation, was completed without any immediate issues.

### A Delayed and Unusual Complication

The unexpected event occurred nearly a full day after the patient was discharged. About 20 hours post-procedure, she experienced an acute decrease in consciousness. Her Glasgow Coma Scale—a standard measure of consciousness—dropped to a nadir of 12 (where 15 is fully alert). Her heart rate pattern was consistent with a vasovagal syncope episode, a reflex that causes a sudden drop in heart rate and blood pressure, reducing blood flow to the brain. No other neurological deficits were found. Crucially, this was a delayed reaction; she gradually recovered full consciousness (GCS 15) over seven hours without specific medical intervention beyond monitoring.

### Symptom Outcomes: Clear Improvements Amidst a Complication

When comparing her symptoms before and after the procedure, the results were notably positive for several key issues. The patient reported clear improvement in cervical paraesthesia (abnormal sensations), her chronic spontaneous vertigo, and her tinnitus. The intensity of her cluster-type headache was also reduced. However, her tension-type headache persisted at a similar level. This mixed outcome demonstrates that while PRF can be effective for certain neuropathic and vestibular components of complex pain syndromes, it is not a universal solution for all headache types. The improvement in vertigo and tinnitus is particularly interesting, suggesting a link between cervical nerve function and vestibular-auditory symptoms, a connection explored in research on cerebellar and neural pathways.

### Understanding the “Why”: The Bezold-Jarisch Reflex

Wijaya and Laksono propose a physiological explanation for the delayed fainting episode. The occipital nerves and upper cervical dorsal root ganglia are anatomically linked to the trigeminocervical complex in the brainstem—a major relay and processing center for pain and sensory information from the head and neck. They hypothesize that the pulsed radiofrequency energy provided sustained afferent (incoming) stimulation to this complex.
This stimulation, in a susceptible individual, may have activated the Bezold-Jarisch reflex. This reflex, typically triggered by certain cardiac conditions, involves a feedback loop that results in increased vagal tone, slowing the heart, dilating blood vessels, and causing a drop in blood pressure—leading to syncope. The 20-hour delay remains unusual but may relate to the slow modulation of nerve activity or post-procedural inflammatory processes.

### Practical Implications for Patient Safety and Treatment

This single case report, detailed in the *Journal of Anesthesia and Clinical Research* (DOI: 10.37275/jacr.v7i1.890), does not negate the overall safety profile of pulsed radiofrequency. However, it adds a critical data point for clinicians and patients. The authors recommend several safety-focused measures:
* **Multimodal Monitoring:** Careful monitoring of vital signs during the procedure.
* **Hydration and Sedation Management:** Ensuring patients are well-hydrated and using careful titration of sedatives like propofol and midazolam.
* **Structured Post-Procedural Observation:** Developing clear discharge guidelines that warn patients of potential delayed events, even a day later. This is similar to the careful management required after other neuromodulation therapies or when diagnosing complex vestibular disorders in vulnerable populations.

For patients considering such procedures for conditions like cervicogenic vertigo or tinnitus, this report underscores the importance of a thorough discussion with a pain specialist. It highlights the need to weigh the documented benefits—which for this patient were significant for several symptoms—against the understanding of rare risks. It also points to the interconnected nature of hearing, balance, and cervical health, a theme consistent with holistic approaches to auditory and neurological processing disorders. Continued documentation of such cases will refine safety protocols and help identify which patients might be more susceptible to these atypical reactions.