Difference between revisions of "6° Clinical case: Facial onset sensory and motor neuronopathy"

In the section "Are we sure to know everything?" from Masticationpedia, the narrative delves into the intricate and nuanced challenges faced in diagnosing orofacial disorders, particularly when differentiating them from more severe organic diseases. This chapter focuses on a specific clinical case of a patient, initially referred from the Gastroenterology department due to unexplained organic food wasting, who was later diagnosed with facial onset sensory and motor neuronopathy (FOSMN), a form of trigeminal degenerative neuropathy.  

The patient, a 40-year-old who had previously undergone maxillofacial surgery for a unilateral crossbite, presented with symptoms that did not initially seem related to her past surgical interventions. Initial trigeminal electrophysiological tests led to a preliminary diagnosis of organic neuromotor damage, which prompted a referral to specialized departments for further examination.

This case highlights the critical importance of considering orofacial pain and headache centers for patients who initially show sensory disturbances on one side, as these may later develop into bilateral trigeminal neuropathy. The narrative stresses that while no effective therapy exists for this condition currently, early and accurate diagnosis is crucial for managing patient expectations and ruling out other treatable causes.

 

 

The patient's journey through the healthcare system illustrates the complex interplay between various specialties and the need for a multidisciplinary approach to diagnosis and treatment. Initial misdiagnoses and the eventual identification of a rare neurological disorder underscore the limitations and challenges within current diagnostic paradigms.

 

This section of Masticationpedia calls for a reevaluation of the training and protocols used in diagnosing TMDs and related conditions. It advocates for an enhanced understanding of the nuances and complexities of orofacial disorders, urging the dental and medical communities to adopt more nuanced and patient-centered diagnostic and treatment strategies.

 

The case of FOSMN presented in the chapter serves as a reminder of the potential for serious neurological conditions to manifest initially with symptoms that may be mistaken for more common orofacial issues. This underscores the necessity for ongoing education, research, and interdisciplinary cooperation in the fields of dentistry and neurology to improve outcomes for patients with complex orofacial conditions.<blockquote>

 

 

 

 

 

 

 

 

 

 

</ref> false negatives and fallacies dictated by specialist contexts etc., so that our infinite clinical intuitive power is amplified and not dampened by easy access to automated machine learning models. This is so true that in an article by Naglaa El-Wakeel,<ref>El-Wakeel N, Ezzeldin N. Diagnostic errors in Dentistry, opinions of egyptian dental teaching staff, a cross-sectional study. BMC Oral Health. 2022 Dec 20;22(1):621. doi: 10.1186/s12903-022-02565-9.PMID: 36539763 </ref> conducted on questionnaires on 151 dentistry professors from Egyptian government and private universities, it emerges that the percentage of diagnostic errors has been estimated to be < 20% and 20-40% of over 90% of the participants. The most commonly misdiagnosed conditions were oral mucosal lesions (83.4%), followed by temporomandibular and periodontal joint conditions (58.9%). The conclusion was that the main causes of this problem are the dental education system and the lack of adequate training. Just a recent report by the National Academies of Science, Engineering and Medicine highlighted a number of shortcomings, particularly in the training of TMDs in dental schools in the United States of America at both the pre-doctoral and post-doctoral (dental) levels, as well as the need to address historical inconsistencies in both diagnosis and treatment. Recently, the American Dental Association recognized orofacial pain as a specialty, which should increase the level and availability of expertise in treating these problems. The article concludes by noting that based on the best current evidence. This report is an attempt to alert the profession to stop irreversible and invasive therapies for the vast majority of TMDs and to recognize that most of these disorders are amenable to conservative and reversible interventions.<ref>Gary D Klasser, Elliot Abt, Robert J Weyant, Charles S Greene. Temporomandibular disorders: current status of research, education, policies, and its impact on clinicians in the United States of America. Quintessence. 2023 Apr 11;54(4):328-334.doi: 10.3290/j.qi.b3999673.

Trigeminal motor evoked potentials were tested by transcranial magnetic stimulation,<ref>Cruccu G, Berardelli A, Inghilleri M, Manfredi M. Functional organization of the trigeminal motor system in man. A neurophysiological study. Brain. 1989;112:1333–1350. doi: 10.1093/brain/112.5.1333.</ref> the temporal H reflex, evaluating the Aα fiber (Ia fiber) in the monosynaptic trigeminal reflex,<ref>Cruccu G, Truini A, Priori A. Excitability of the human trigeminal motoneuronal pool and interactions with other brainstem reflex pathways. J Physiol. 2001;531:559–571. doi: 10.1111/j.1469-7793.2001.0559i.x.</ref> the early components of the blink reflex (R1) after electrical stimulation of the supraorbital nerve, and the masseter inhibitory reflex (SP1) after stimulation of the mental nerve, assessing the fibers <math>A\beta</math>.<ref>Valls-Solé J. Neurophysiological assessment of trigeminal nerve reflexes in disorders of central and peripheral nervous system. Clin Neurophysiol. 2005;116:[tel:2255–2265 2255–2265]. doi: 10.1016/j.clinph.2005.04.020.</ref> Laser-evoked potentials (LEP) were also recorded to study nociceptors <math>A\delta</math>(<math>A\delta</math>-LEP) and unmyelinated fiber heat receptors (C-LEP).<ref>Cruccu G, Pennisi E, Truini A, Iannetti GD, Romaniello A, Le Pera D, De Armas L, Leandri M, Manfredi M, Valeriani M. Unmyelinated trigeminal pathways as assessed by laser stimuli in humans. Brain. 2003;126:[tel:2246–2256 2246–2256]. doi: 10.1093/brain/awg227.</ref> The neurophysiological tests have adhered to the technical requirements issued by the International Federation of Clinical Neurophysiology.<ref>Kimura J, editor. Peripheral Nerve Diseases, Handbook of Clinical Neurophysiology.Amsterdam: Elsevier; 2006.</ref><ref>Cruccu G, Aminoff MJ, Curio G, Guerit JM, Kakigi R, Mauguiere F, Rossini PM, Treede RD, Garcia-Larrea L. Recommendations for the clinical use of somatosensory-evoked potentials. Clin Neurophysiol. 2008;119:1705–1719. doi: 10.1016/j.clinph.2008.03.016.</ref>

From the study by Cruccu et al.<ref name=":0">Cruccu G, Pennisi EM, Antonini G, Biasiotta A, di Stefano G, La Cesa S, Leone C, Raffa S, Sommer C, Truini A.Trigeminal isolated '''sensory''' neuropathy (TISN) and FOSMN syndrome: despite a dissimilar disease course do they share common pathophysiological mechanisms? BMC Neurol. 2014 Dec 19;14:248. doi: 10.1186/s12883-014-0248-2.PMID: 25527047 </ref> first of all it is deduced that despite detailed neurophysiological and morphometric investigations, no clinical, neurophysiological or neuropathological differences can be found between TISN and FOSMN, therefore, the two diseases could be pathophysiologically similar neuropathies of the type of dissociated neuropathies that completely spare the unmyelinated fibers as demonstrated by the biopsy exam. Light and electron microscopy in supraorbital nerve biopsy specimens from patients with TISN and those with FOSMN have shown variously severe axonal myelinated fiber loss, as others have reported in these patients.<ref>Lecky BR, Hughes RA, Murray NM. Trigeminal sensory neuropathy. A study of 22 cases. Brain. 1987;110:1463–1485. doi: 10.1093/brain/110.6.1463. </ref><ref name=":1">Vucic S, Tian D, Chong PS, Cudkowicz ME, Hedley-Whyte ET, Cros D. Facial onset sensory and motor neuronopathy (FOSMN syndrome): a novel syndrome in neurology. Brain. 2006;129:[tel:3384–3390 3384–3390]. doi: 10.1093/brain/awl258.</ref> We extend these findings by providing quantitative data showing that trigeminal neuropathy affects fibers <math>A\beta</math> more severely than fibers<math>A\delta</math>. Evidence that nerve fiber damage progresses from the largest to the smallest fiber also comes from neurophysiological findings, which invariably show responses mediated by the impaired fiber <math>A\beta</math> even in the early stages of the disease. In contrast, <math>A\delta</math> fiber-mediated responses were much less impaired.