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Difference between revisions of "1° Clinical case: Hemimasticatory spasm"
1° Clinical case: Hemimasticatory spasm (view source)
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In this clinical iter that we have presented, the choice of the clinician to follow the electrophysiological trigeminal roadmap from which the positivity of the <math>\bar{\gamma_n}=1</math> assertions have already been derived, therefore, having already defined a picture of serious anomaly of absence of the jaw jerk and of the silent period masseterino on the right side of the patient will have to understand if the damage is intracranial or extracranial. | In this clinical iter that we have presented, the choice of the clinician to follow the electrophysiological trigeminal roadmap from which the positivity of the <math>\bar{\gamma_n}=1</math> assertions have already been derived, therefore, having already defined a picture of serious anomaly of absence of the jaw jerk and of the silent period masseterino on the right side of the patient will have to understand if the damage is intracranial or extracranial. | ||
To do this, the clinician uses an electrical stimulation test of the masseter nerve in infratemporal fossa called <math>M-wave</math> on the masseter muscle with simultaneous recording of the heteronymous <math>H-wave</math> on the temporal muscle<ref>G | To do this, the clinician uses an electrical stimulation test of the masseter nerve in infratemporal fossa called <math>M-wave</math> on the masseter muscle with simultaneous recording of the heteronymous <math>H-wave</math> on the temporal muscle<ref>{{cita libro | ||
| autore = Cruccu G | |||
</ref> and a bilateral transcranial electrical stimulation of the trigeminal motor roots called, precisely, <math>_bRoot-MEPs</math><ref name=" | | autore2 = Truini A | ||
| autore3 = Priori A | |||
| titolo = Excitability of the human trigeminal motoneuronal pool and interactions with other brainstem reflex pathways | |||
| url = https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2278464/pdf/tjp0531-0559.pdf | |||
| volume = | |||
| opera = J Physiol | |||
| anno = 2001 | |||
| editore = The Physiological Society | |||
| città = | |||
| ISBN = | |||
| DOI = 10.1111/j.1469-7793.2001.0559i.x | |||
| PMID = 11230527 | |||
| PMCID = PMC2278464 | |||
| oaf = <!-- qualsiasi valore --> | |||
| LCCN = | |||
| OCLC = | |||
}}</ref> and a bilateral transcranial electrical stimulation of the trigeminal motor roots called, precisely, <math>_bRoot-MEPs</math><ref name="fris1992">{{cita libro | |||
| autore = Frisardi G | |||
| titolo = The use of transcranial stimulation in the fabrication of an occlusal splint | |||
| url = https://www.sciencedirect.com/science/article/abs/pii/002239139290345B | |||
| volume = | |||
| opera = J Prosthet Dent | |||
| anno = 1992 | |||
| editore = Mosby, Inc - Elsevier | |||
| città = | |||
| ISBN = | |||
| DOI = 10.1016/0022-3913(92)90345-b | |||
| PMID = 1501190 | |||
| PMCID = | |||
| oaf = <!-- qualsiasi valore --> | |||
| LCCN = | |||
| OCLC = | |||
}}</ref> | |||
====M-wave ==== | ====M-wave ==== | ||
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====<sub>b</sub>Root-MEPs==== | ====<sub>b</sub>Root-MEPs==== | ||
The trigeminal root was stimulated transcrally through high voltage, low impedance through an electrical stimulator (Neuropack X1, Nihon Kohden Corporation, Tokyo, Japan)) with the anode electrode positioned at the apex and the cathode approximately 10 cm laterally from the apex along a line vertex acoustic meatus. The electric field is believed to excite the trigeminal motor nerve fibers via the trancranial route, near their exit from the skull.<ref name=" | The trigeminal root was stimulated transcrally through high voltage, low impedance through an electrical stimulator (Neuropack X1, Nihon Kohden Corporation, Tokyo, Japan)) with the anode electrode positioned at the apex and the cathode approximately 10 cm laterally from the apex along a line vertex acoustic meatus. The electric field is believed to excite the trigeminal motor nerve fibers via the trancranial route, near their exit from the skull.<ref name="fris1992" /><ref>G Frisardi, P Ravazzani, G Tognola, F Grandori. [https://pubmed.ncbi.nlm.nih.gov/9467995/ Electric versus magnetic transcranial stimulation of the trigeminal system in healthy subjects. Clinical applications in gnathology.] J Oral Rehab.1997 Dec;24(12):920-8.doi: 10.1046/j.1365-2842.1997.00577.x.</ref> Also in this case, the response in the right masseter was markedly delayed (3.5 ms on the right side 2 ms on the left and dispersed. amplitude of the M-wave. | ||
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=== Conclusions === | === Conclusions === | ||
Following this step by step path we have demonstrated a peripheral motor nerve injury as originally proposed by Kaufman.<ref name=" | Following this step by step path we have demonstrated a peripheral motor nerve injury as originally proposed by Kaufman.<ref name="kauf">Kaufman MD. [https://pubmed.ncbi.nlm.nih.gov/7436363/ Masticatory spasm in facial hemiatrophy]. Ann Neurol 1980;7:585-7.</ref> Conduction studies have shown a slowing of conduction in the extracranial course of masticatory nerve fibers without a reduction in the amplitude of <math>M-wave</math> and obviously EMG signs of chronic denervation. The temporal muscle biopsy appeared histologically normal. | ||
{{Q2|These results indicate axon-sparing demielination.}} | {{Q2|These results indicate axon-sparing demielination.}} | ||
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Muscle nerve damage would not be explained only because patients with Hemimasticatory Spasm (HMS) do not have sensory disturbances but also because they often only have spasms in one or two levator mandibular muscles. These observations argue against damage to the motor root or to the intracranial portion of the mandibular nerve where the motor bundles are closely grouped,<ref>Pennisi E, Cruccu G, Manfredi M, Palladini G. [https://pubmed.ncbi.nlm.nih.gov/1795166/ Histometric study of myelinated fibers in the human trigeminal nerve]. J Neurol Sci 1991;105:22-8.</ref> favoring damage to the individual muscle nerves that pass through the infratemporal fossa. | Muscle nerve damage would not be explained only because patients with Hemimasticatory Spasm (HMS) do not have sensory disturbances but also because they often only have spasms in one or two levator mandibular muscles. These observations argue against damage to the motor root or to the intracranial portion of the mandibular nerve where the motor bundles are closely grouped,<ref>Pennisi E, Cruccu G, Manfredi M, Palladini G. [https://pubmed.ncbi.nlm.nih.gov/1795166/ Histometric study of myelinated fibers in the human trigeminal nerve]. J Neurol Sci 1991;105:22-8.</ref> favoring damage to the individual muscle nerves that pass through the infratemporal fossa. | ||
The mechanism of involvement of facial paroxysmal involuntary activity has been discussed by Kaufnan<ref name=" | The mechanism of involvement of facial paroxysmal involuntary activity has been discussed by Kaufnan<ref name="kauf" /> and by Thompson and Carroll<ref>Thompson PD, Carroll WM. [https://pubmed.ncbi.nlm.nih.gov/6842234/ Hemimasticatory spasm: a peripheral paroxysmal cranial neuropathy?] J Neurol NeurosurgPsychiatry 1983;46:274-6.</ref> who emphasized the close similarity between hemimasticatory and hemifacial spasm. | ||
In EMG, these prolonged spasms fit perfectly into the description of cramps, that is, discharges of irregular motor units that progressively increase, leading to the recruitment of much of the muscle of synchronous discharges at speeds of 40 to 60 Hz.<ref>Kimura J. Electrodiagnosis in diseases of nerve and muscle: principles and practice, 2nd edn. Philadelphia: FA Davis 1989.</ref> Common to hemifacial spasm and cramps however, ectopic EMG activities can also be detected. | In EMG, these prolonged spasms fit perfectly into the description of cramps, that is, discharges of irregular motor units that progressively increase, leading to the recruitment of much of the muscle of synchronous discharges at speeds of 40 to 60 Hz.<ref>Kimura J. Electrodiagnosis in diseases of nerve and muscle: principles and practice, 2nd edn. Philadelphia: FA Davis 1989.</ref> Common to hemifacial spasm and cramps however, ectopic EMG activities can also be detected. | ||
This could be responsible for the high frequency of EMG discharges at a frequency of 100-200 Hz and the synchronization of the entire muscle or multiple muscles, and post-activity. The synchronization could be explained by the lateral spread of discharges from adjacent nerve fibers,<ref>Nielsen VK. [https://pubmed.ncbi.nlm.nih.gov/6322049/ Pathophysiology of hemifacial spasm: II. Lateral spread of the supraorbital nerve reflex]. Neurology 1984;34:427-31.</ref><ref>Thompson PD. Stiff people. In Fahn S, Marsden CD, eds. Movement disorders 3. London: Butterworths, 1993: 367-99.</ref> generating a local re-excitation circuit. Posthumous EMG activity consists of paroxysmal discharges that may follow a voluntary orthodromic contraction or antidromic impulses,<ref>Auger RG. [https://pubmed.ncbi.nlm.nih.gov/573406/ Hemnifacial spasm: clinical and electrophysio- logic observations.] Neurology 1979;29: 1261-72.</ref><ref name=" | This could be responsible for the high frequency of EMG discharges at a frequency of 100-200 Hz and the synchronization of the entire muscle or multiple muscles, and post-activity. The synchronization could be explained by the lateral spread of discharges from adjacent nerve fibers,<ref>Nielsen VK. [https://pubmed.ncbi.nlm.nih.gov/6322049/ Pathophysiology of hemifacial spasm: II. Lateral spread of the supraorbital nerve reflex]. Neurology 1984;34:427-31.</ref><ref>Thompson PD. Stiff people. In Fahn S, Marsden CD, eds. Movement disorders 3. London: Butterworths, 1993: 367-99.</ref> generating a local re-excitation circuit. Posthumous EMG activity consists of paroxysmal discharges that may follow a voluntary orthodromic contraction or antidromic impulses,<ref>Auger RG. [https://pubmed.ncbi.nlm.nih.gov/573406/ Hemnifacial spasm: clinical and electrophysio- logic observations.] Neurology 1979;29: 1261-72.</ref><ref name="niels">Nielsen VK. [https://pubmed.ncbi.nlm.nih.gov/6322048/ Pathophysiology of hemifacial spasm: I. Ephaptic transmission and ectopic excitation.] Neurology 1984;34:418-26.</ref> and is attributed to self-excitation of the same axons after the passage of an impulse. | ||
In our patient Mary Poppins we observed a synchronization of the whole or a large part of the muscle involved in the spasm (fig 10, EMG); the self-excitation is evidenced by the recording of the evoked discharges following the response of the stimulation of the chewing nerves (Fig. 10, E). These results support the hypothesis that spontaneous activity 'arises' in a demyelinated peripheral nerve, a phenomenon called hepaptic.<ref name=" | In our patient Mary Poppins we observed a synchronization of the whole or a large part of the muscle involved in the spasm (fig 10, EMG); the self-excitation is evidenced by the recording of the evoked discharges following the response of the stimulation of the chewing nerves (Fig. 10, E). These results support the hypothesis that spontaneous activity 'arises' in a demyelinated peripheral nerve, a phenomenon called hepaptic.<ref name="niels" /> | ||
In conclusion, the patient was affected by 'Hemimasticatory Spasm' mainly focused on the right masseter muscle but with indirect diffusion of the phenomenon to the right temporal muscle probably due to hepaptic activity due to the demyelination of the masticatory motor nerves in the infratemporal fossa. Botulinum endotoxin therapy was started immediately with total regression of the disease 10 years later. | In conclusion, the patient was affected by 'Hemimasticatory Spasm' mainly focused on the right masseter muscle but with indirect diffusion of the phenomenon to the right temporal muscle probably due to hepaptic activity due to the demyelination of the masticatory motor nerves in the infratemporal fossa. Botulinum endotoxin therapy was started immediately with total regression of the disease 10 years later. | ||