"What appeared to be uncontrollable, tic-like sneezes for nearly a decade was ultimately recognized as a distinct manifestation of functional neurological disorder, highlighting the complexity and often misunderstood nature of these genuine neurological conditions."
A peculiar and persistent affliction, initially mistaken for habitual or perhaps allergy-induced sneezing, baffled a 32-year-old teacher for nine years. His episodes, characterized by forceful diaphragm contractions, nasal exhalations, and rhythmic vocalizations, mimicked sneezes so closely that they were, for a long time, simply categorized as such. However, these were not ordinary sneezes. The intensity and frequency of these attacks, sometimes occurring up to 78 times a day and lasting as long as 10 minutes, significantly impacted his life, even disrupting his sleep. This case, detailed in Movement Disorders Clinical Practice, introduces "functional sneeze," a proposed new subtype of functional neurological disorder (FND), shedding light on a condition that often evades conventional diagnosis and treatment.
The narrative of the functional sneeze is anchored by a pivotal event: the onset of these symptoms shortly after surgery to repair a fractured left arm. The procedure involved the implantation of a metal plate under general anesthesia. This detail is crucial, as physical trauma, surgery, and anesthesia are recognized triggers for the development of functional neurological disorder. Unlike a mere coincidence, such events are frequently reported in the medical histories of individuals presenting with FND symptoms. Despite an otherwise unremarkable medical history, including his continued work as a teacher and an active lifestyle, standard neurological investigations yielded no identifiable organic cause. This lack of physical evidence is not an oversight in the diagnostic process but rather a characteristic feature that can unfortunately lead to dismissal or prolonged diagnostic delays.
Functional neurological disorder, formerly known as conversion disorder, has undergone a significant paradigm shift in understanding. The outdated notion that symptoms were purely psychological or "imagined" has been replaced by a more nuanced, neurobiological perspective. FND is now understood as a disorder of brain network function, specifically affecting how the brain processes movement, attention, and the sense of voluntary control. It is not a sign of damage to the physical structure of the nervous system, but rather a disruption in its operational wiring. Crucially, the symptoms experienced by individuals with FND are genuine, involuntary, and not consciously produced. They are as real and debilitating as those stemming from structural neurological damage.
The prevalence of FND underscores its significance in neurological practice. It stands as the second most common reason for patients to seek consultation with a neurologist, surpassed only by headaches. FND accounts for an estimated 5% to 10% of new neurological appointments. Epidemiological studies present a wide range of incidence and prevalence figures, with estimates suggesting an incidence of 10 to 22 per 100,000 people and a minimum prevalence of 80 to 140 per 100,000. However, these figures are likely conservative due to significant heterogeneity in study methodologies and the substantial diagnostic delays often encountered. These delays, which can stretch for years, contribute to chronic symptom development and disability, a grim prognosis that underscores the need for earlier recognition and intervention. Indeed, clinical reviews indicate that the incidence of FND is comparable to that of conditions like multiple sclerosis and amyotrophic lateral sclerosis (ALS), highlighting its widespread impact. The nine-year delay in the case of the functional sneeze is a stark illustration of this diagnostic challenge.
The formal naming of "functional sneeze" as a subtype of FND, while seemingly a minor addition to a broad spectrum of presentations, carries significant practical implications. FND encompasses a wide array of symptoms, including functional seizures, tremor, weakness, gait disturbances, speech impairments, and sensory deficits. The addition of functional sneeze provides a specific diagnostic category for clinicians encountering these particular tic-like episodes. Without such a classification, patients presenting with sneezing fits unresponsive to antihistamines, lacking an identifiable nasal pathology, and showing no abnormalities on imaging would face considerable diagnostic uncertainty. A named pattern offers a concrete framework for diagnosis, moving beyond a mere diagnosis of exclusion after exhaustive testing.
Moreover, the modern approach to diagnosing FND emphasizes positive diagnostic features rather than solely relying on ruling out other conditions. Clinicians actively seek characteristic signs such as symptom variability over time, distractibility, sudden onset, and patterns inconsistent with known neurological diseases. This positive diagnostic approach validates the patient’s experience and guides appropriate management strategies.
The journey of the teacher with functional sneeze was marked by periods of improvement and relapse, illustrating the complex and often fluctuating nature of FND. Following his initial presentation at a functional neurological disorder clinic, his symptoms were well-controlled for several years. However, a relapse occurred five years later. The attacks escalated in intensity and duration, accompanied by new symptoms such as dribbling and dissociation. These relapses, occurring without an obvious trigger, became less predictable and more challenging to manage, leading him to reduce his physical activity and avoid social engagements. A particularly distressing social event triggered a significant worsening, with approximately 30 episodes occurring in a single day. Concurrently, he began experiencing increasing pain in his left arm, despite no new injury. Specialist talking therapy, informed by cognitive behavioral principles, proved ineffective in alleviating these recurrent symptoms.
A turning point arrived two years after the onset of his relapse, when surgeons surgically removed the metal plate from his left arm. In the two months following this intervention, he experienced a dramatic improvement, reporting only a single mild sneeze episode, a stark contrast to the multiple daily distressing episodes he had endured. This outcome is striking and warrants careful consideration and caution. It is crucial to emphasize that this represents a single case study. One patient’s experience cannot definitively establish a causal link between the plate and the symptoms, nor can it guarantee the long-term efficacy of its removal. Furthermore, it does not immediately solidify "functional sneeze" as a universally accepted distinct subtype, nor should it be interpreted as a general recommendation for hardware removal in similar cases.
The transferable insight for individuals experiencing persistent involuntary movements that defy conventional explanation is the importance of persistent investigation with a neurologist. A normal MRI scan, while crucial in ruling out structural damage, does not equate to the absence of a neurological issue. Diagnosing functional neurological disorder is a clinical undertaking that relies heavily on a thorough neurological examination and skilled clinical judgment, elements that cannot be replicated by self-diagnosis or solely through diagnostic imaging. The case of the functional sneeze underscores the ongoing evolution of our understanding of neurological disorders and the critical need for both clinicians and patients to be aware of the diverse and sometimes surprising manifestations of functional neurological disorder.
