- Email: [email protected]
Amyotrophic lateral sclerosis
Amyotrophic lateral sclerosis Neal W. Roller, D.D.S.,* Adrian. Garfunkel, D.M.D.,* Chris Nichols, D.D.S.,*’ and Irwin I. Ship, D.M.D., M.SC.,~** Philadelphia, Pa. DEPARTMENT DENTAL
OF ORAL
MEDICINE,
PHILADELPHIA
AND
GENERAL
MEDICINE, DEPARTMENT
UNIVERSITY OF DENTAL
OF PENNSYLVANIA RESEARCH,
SCHOOL
OF
THE
HOSPITAL
Amyotrophic lateral sclerosis, a type of motor neuron disease, is a uniformly fatal neurologic disorder characterized by inexorably progressive destruction of upper and lower motor neurons. The disease is of interest to dentists because patients with motor disability involving the mouth and pharynx may initially seek dental consultation. This article presents a case of amyotrophic lateral sclerosis with predominantly bulbar involvement. The mode of clinical presentation and the management of the patient with motor neuron disease are discussed.
V
arious reports list dysarthria and/or dysphagia as the presenting complaint of 9 to 26 per cent of all patients with motor neuron disease.1-3 Bosma4 has stressed that some entities of progressive motor impairment are most clearly identified in the oral and pharyngeal regions. Almost all patients eventually show oral or pharyngeal involvement. Because these initial complaints are so closely linked with the functioning of the mouth, it is reasonable to expect that many patients with motor neuron disease will consult their dentists. The proportion of patients who elect to consult dentists about these symptoms is unknown, as reports of motor neuron disease in the dental literature are virtually nonexistent. Amyotrophic lateral sclerosis (ALS) is a rare disease, most often seen in the classic sporadic form. However, two other types have been described: a type unique to the island of Guam and a type known as familial ALS.2* 5*E This article will be confined to a discussion of the classic form of ALS. An accurate estimate of the incidence of ALS has not been possible because it is so infrequently seen in the general population.2 Males are affected more These studies were supported by the Oral Medicine Research Training Program, 5TOlDE77, for the National Institute of Dental Research, NIH, to the Department of Dental Research, The Philadelphia General Hospital. *Postdoctoral Oral Medicine Trainee. **Associate in Oral Medicine. **‘Professor and Chairman, De artment of Oral Medicine, University of Pennsylvania School of Dental Medicine, and Chle4 of Dental Research, The Philadelphia General Hospital.
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than females, in a rat.io of 2 :l. The insidious onset is usually in the fourth to the sixth decade, although it has been reported as early as age 14.7 The upper motor neurons, which constitute the corticospinal or pyramidal tract, arise from the principal motor area of the cortex, which is located in the posterior part of the frontal lobe immediately in front of the central sulcus. The most outstanding fibers in the corticospinal tract are the large myelinated fibers that originate in the giant Betz cells of the motor area and account for approximately 3 per cent of the total number of corticospinal fibers. The remaining fibers are smaller and only 60 per cent are myelinated.* Stimulation of the cells in the lower lateral part of the motor area causes bilateral movement in .the pharynx, larynx, face, and jaw, while stimulation of the midline and superior portion of this area causes movement in the legs, feet, and toes. As the corticospinal tract descends through the brain stem, it gives off fibers which travel to the contralateral motor nuclei of the cranial nerves. Below the medulla the major portion of the corticospinal fibers decussate to form the lateral corticospinal tract. The lateral corticospinal tract synapses with internuncial neurons ending on the anterior horn cells of the spinal cord. The final common path of motor activity is the lower motor neuron which transmits impulses from the anterior horn cells of the spinal cord and from the motor cells of the brain stem to the voluntary muscles. A lesion of the lower motor neurons will result in a diminished ‘tendon reflex, with weakness and wasting of the muscles (as seen in progressive bulbar palsy and progressive muscular atrophy), whereas a lesion of the corticospinal tract above the medulla will cause exaggerated reflexes and spastic muscles (as seen in pseudobulbar palsy). Amyotrophic lateral sclerosis is characterized pathologically by degenerative changes in the motor neurons involving the corticospinal tracts (upper motor neurons), the motor cells of the brain stem, and the anterior horn cells of the spinal cord (the lower motor neurons). Involvement of lower motor neurons alone was first described by Aran and Duchenne,lO who called the disease progressive muscular atrophy. Charcot and Joffroyll used the term amyotrophic lateral sclerosis to describe lower motor neuron lesions associated with corticospinal tract involvement. When the muscles innervated by the cranial nerves are affected primarily, the term progressive bulbar (pertaining to the medulla oblongata) palsy is often used. Pseudobulbar pa7sy, which affects the corticospinal tracts above the medulla, is differentiated from progressive bulbar palsy by spastic, as opposed to wasted, hypotonic muscles and by frequent impairment of voluntary control over emotion. All these entities describe motor neuron disease and differ from each other only in location of the primary lesion.2j 12~l3 ETIOLOGY Trauma, inflammation, toxic or heavy metal poisoning, metabolic disorders, viral infections, associated cancer, dietary deficiencies, vascular diseases, and stress have all been suggested as etiologic or contributing factors. In most reported cases, the relationship is doubtful and so far no conclusive evidence has been presented to document the cause of AI&. The most frequently cited etiologic agent is trauma.2 Alpers and Farmerl* are among the authors who have supported trauma as the etiologic factor, but
48
Roller et al.
Oral Surg. .January,
1974
most other authors find no relationship to trauma.‘j BrownI reported one case of ALS in a farmer suffering from chronic mercury poisoning. Studies on Guam failed to show an increased incidence in the military population stationed on the island during World War II and did not support an environmental or infectious agent. as the etiologic factor.6 CLINICAL PICTURE The nature of the earliest symptoms of amyotrophic lateral sclerosis depends upon the region of the nervous system first affected. Koerner,2 in a survey of thirty-five cases, noted initial spinal involvement in twenty-seven cases, initial bulbar involvement in three, and a combination of spinal and bulbar involvement in five cases. Mackay,l in a total of seventy patients, noted spinal onset in forty-four, bulbar onset in eleven, and a combination in fifteen. Anterior motor neuron degeneration is usually first seen as muscular wasting in the hands, especially in the muscles of the thenar eminences. The patient may be conscious of weakness, stiffness, or clumsiness of movements of the fingers. Often asymmetric initially, the weakness and muscular wasting gradually becomes symmetric and widespread. I7 The lower limbs are usually less affected than the upper limbs, with weakness of the legs seen only in later stages of the disease. Fasciculation is a prominent symptom. This involuntary contraction of groups of muscles, apparent through intact skin, has been considered evidence of disease of the anterior horn cell.‘* The disease will eventually, if not initially, affect the nuclei of the cranial nerves, The hypoglossal nucleus is the most commonly affected; fifty of fiftythree cases in one study3 and thirty-one of thirty-five in another2 showed involvement of the twelfth cranial nerve. The tongue shows conspicuous symmetrical fasciculations and eventually muscular atrophy. Protrusive movements of the tongue are at first weak and later lost. There is often an associated paresis of the orbicularis oris. Bing and associates I9 believe that the uppermost part of the hypoglossal nucleus contributes fibers to the facial nerve, which may explain the occurrence of this weakness of the orbicularis oris even when the facial nerve is otherwise unaffected. The nucleus ambiguus, composed of cranial nerves IX and X and some fibers from XI, is the next most frequently affected. It, supplies motor fibers to the soft palate, pharynx, and larynx. The glossopharyngeal (IX) has minimal motor function, supplying the stylopharyngeus and possibly the superior constrictor of the pharynx. Because the vagus (X) supplies the main motor innervation to these same muscles, it is clinically difficult to test the motor function of IX.2o Thus, when one is considering the nerve supply to the soft palate, pharynx, and larynx, the vagus is the cranial nerve tested clinically and is mainly responsible for the clinical manifestations. In ALS involving the vagal nuclei, the soft palate is atrophic and motionless and hangs low. With advancing disease, coughing and swallowing become difficult and regurgitation of fluids and foods through the nose is frequent. Ultimately, the patient cannot yawn, sniff, hum, or blow his n0se.l’ Speech suffers as a result of paresis of the lips, tongue, and palate and becomes slurred and then unintelligible. The vocal cords may be paretic or
Amyotrophic
lateral
sclerosis
49
paralyzed. The voice then becomes hoarse, and eventually the patient is aphonic. Involvement of the spinal accessory motor nuclei (XI) results in weakness and fasciculations of the upper trapezius and sternomastoid muscles. There is a tendency for the head to fall backward since both sternomastoids flex the head forward. When the seventh and fifth cranial nuclei are affected, the muscles of mastication are weakened, chewing becomes difficult, and there is often severe malocclusion. In the late stages of the disease, the mandibular inserting muscles may become extremely weak, requiring manual support of the jaw. Temporomandibular joint dysfunction, evidenced by dislocations, instability, and bilateral hypermobility, is sometimes present.21 The nuclei of the third, fourth, and sixth cranial nerves are usually spared. Examination of reflexes is important in evaluating a patient suspected of having a motor neuron disease. In disease states, the various alterations of deep tendon reflexes indicate the. location of pathologic processes along the reflex arch pathway. Degeneration of the lower motor neurons causes hyporeflexia ; corticospinal degeneration leads to hyperreflexia. Corticospinal tract lesions in or above the upper brain stem can be tested by the jaw jerk. This reflex is elicited by means of a sharp downward tap on the chin with the mouth held partly open. Exaggerated contraction of the masseter muscles indicates a positive diagnosis.22 With involvement of the vagus motor nuclei by ALS, the palatal and pharyngeal reflexes may be depressed. The normal palatal reflex produces arching of the soft palate when it is softly touched. The pharyngeal or gag reflex is produced by touching the posterior pharyngeal wall. The motor function of the vagus, trigeminal, and hypoglossal nerves can also be tested by the swallowing reflex. There are additional reflexes which are of value in the diagnosis of corticospinal tract lesions. The extensor plantar reflex (Babinski) is virtually diagnostic of a lesion of the corticospinal tract at any point in its course from the motor cortex down through the brain stem.22 Also useful in diagnosis is the abdominal reflex, which, while normally decreased in corticospinal tract degeneration, is for some reason preserved until late in the course of ALS. The sphincters in ALS are usually minimally affected. DIAGNOSIS
Motor neuron disease, in its later stages, can be diagnosed with reasonable confidence.12 Progressive muscle atrophy and muscle fasciculation, no sensory loss, and some evidence of corticospinal tract disease should stimulate further neurologic investigation. Laboratory test findings are usually within normal limits or, if altered, are usually abnormal as a result of intercurrent disease. PROGNOSIS
Amyotrophic lateral sclerosis is a fatal disease with varying rates of progression, depending on the sites of degeneration. Life expectancy in patients with predominantly lower motor neuron involvement is from 3 to 5 years; however, bulbar involvement decreases the expectancy to 2 to 3 years. Bulbar involvement causing respiratory difficulties leading to aspiration pneumonia is the usual proximate cause of death.
50
Roller
et al.
Oral Surg. .January,
1974
TREATMENT
The approach to treatment of amyotrophic lateral sclerosis has been as varied as the reported etiologic factors. Antiviral agent6 24 and various ritamins have been tried, but the results have been uniformly discouraging. The only treatment is supportive care. Tricyclic antidepressants have been helpful in many cases, as it is likely that there exists a severe underlying depression2” CASE REPORT A 59.year-old male dentist was referred to the Oral Medicine Clinic of Philadelphia General Hospital with a chief complaint of inability to speak clearly and difficulty in eating and swallowing. The patient’s professional associates and family first began noticing a slurring of his speech approximately ll$ years prior to presentation. The speech difficulty progressively worsened. On presentation, it was difficult for the patient to communicate orally, and written remarks were necessitated. Eating firm food and taking liquids caused choking, and at times food was forcefully ejected, occasionally through the nose, but without aspiration. Eating a sandwich could take up to s hour. Saliva accumulated in the mouth, and the patient drooled from the corner of the mouth, especially during sleep. The patient had noticed muscular faciculations in the shoulder. No inappropriate emotional responses were reported. There was no loss of or aberrations in taste. No painful or sensitive areas were reported. Except for dysphagia, the patient had no difficulty practicing his profession, and he continued to work a full schedule. The medical history was unremarkable. There was no family history of neurologic disorders, including poliomyelitis. Drug allergies or exposure to heavy metals or toxins were denied. No head or neck injuries were reported. There was no history of recent falls or loss of balance. The patient had discontinued smoking many years ago and had recently discontinued all alcohol consumption. No sphincter disturbances were reported. During the last several months the patient had sought consultations with a speech therapist, a dentist, and a neurologist. The patient reported the examinations as nonrevealing and not helpful. Bite-positioning appliances had been constructed to correct a faulty occlusion, and the patient had been instructed in tongue-strengthening exercises. Physical examination revealed a well-developed, moderately thin, alert, intelligent, and cooperative patient. No disturbances in gait were noted. No loss of memory or recall was observed. Blood pressure was 140ho; the pulse was 76 and regular; and oral temperature was 98.8” F. The platysma, sternomastoid, pectoralis, biceps, and trapezius muscles showed fasciculations that could be especially elicited upon gentle tapping. Gross testing revealed that there was no muscle weakness, and strength was symmetrically equal. The pupils were equal and reacted to light and accommodation. No papilledema, nystagmus, or retinovascular changes were noted. The optic discs were flat. Examination of the cranial nerves was nonrevealing except for the hypoglossal, vagus, and spinal accessory. The speech was nasal and almost incomprehensible. Air audibly escaped through the nose during normal breathing.
The jaw jerk was moderately active; absent. The plantar response was flexor. and symmetrical in all areas tested.
the gag and pharyngeal reflexes were completely The abdominal and tendon reflexes were normal
Oral examination The most impressive finding on oral examination was that of muscular fasciculations, most obvious in the tongue but also observed in the orbicularis oris and the pharyngeal muscles. An occasional fasciculation was noted in the masseters, but the muscles of mastication did not show atrophy or noticeable weakness. The weakness of the orbieularis oris was
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demonstrated by an inability to whistle or purse the lips. The tongue was lobulated and slightly enlarged in size, with a notable restriction in protrusive movements plus inability to elevate and extend laterally. The mouth was free of mucosal lesions. The teeth were adequately restored and showed evidence of recent occlusal equilibration. Copius foamy saliva was pooled in the floor of the mouth and in the mandibular labial vestibule. The periodontium was healthy. Attempts to consecutively reproduce a centric jaw relationship failed. The patient’s history and physical findings indicated a motor neuron disease. A diagnosis of amyotrophic lateral sclerosis with predominantly bulbar involvement was suspected and later was confirmed by consultation with a neurologist. The following recommendations were made : 1. Continue part-time work, with adequate periods of rest. 2. Avoid exposure to infections, especially respiratory infections. At the first sign of infection, immediately obtain medical attention. 3. Maintain nutrition by a semisolid diet, best obtained with the use of a blender. 4. Continue on a program of moderate exercises, including tongue exercises. 5. On a regular basis have medical checkups, especially if there is increased difficulty in swallowing or eating. Six months after the initial visit a gastrostomy was performed but was not comfortable, and later an esophagostomy was better tolerated. There was increasing respiratory difficulty, medications were complicated by inability to swallofv accumulated saliva. Anticholinergic helpful in reducing salivary secretions.
DISCUSSION The patient with motor disabilities that involve the oral and pharyngeal regions may first seek consultation with a dentist. It is important for the dentist to recognize a progressive motor disability and not attempt to manage the condition without an understanding of the nature and severity of the disease. Treatment of a malocclusion or muscular weakness without knowing the cause of the symptoms would be a disservice to the patient. If a motor disability is suspected, it is imperative that a neurology consultation be obtained. Management of the complications of the disease requires the close cooperation of dentist and physician. The dentist must also be aware that he may be consulted by a patient whose disease has been correctly diagnosed and is seeking another, more reassuring opinion. Brown and Mueller,25 in evaluating the psychologic make-up of ten patients with ALS, noted that many of them had achieved vocational and financial success, were independent, and were highly competent. Many believed that they could “beat” the disease and went to extremes to continue in a semblance of their accustomed life styles. Some denied the disease, expressing little concern over the “disease Lou Gehrig had.” Patients of this type could be tempted to start on a protracted search for a nonexistent cure for their disease. The patient may not be satisfied that there is no effective treatment and go to considerable expense and effort in attempting to find help. Of concern to the dentist or physician is the type of patient mentioned above who may be tempted to seek advice from a paraprofessional who may offer inappropriate therapy while the patient’s condition is deteriorating. SUMMARY When the onset of amyotrophic lateral sclerosis is predominantly origin, the patient may first consult a dentist because of the oral-facial
bulbar, in symptoms
52
Roller
et al.
Oral Surg. January,
1974
of dysphagia, dysarthria, and muscular weakness. The diagnosis can be reasonably ascertained from it simple neurologic examination, and this should cause the dentist to recommend a neurology referral. It is stressed that some of these patients may also visit the dentist seeking an alternative diagnosis, in which case the dentist has a responsibility to the patient to prevent him from continuing a search for a cure that is not at this time to be found. REFERENCES 1. Mackay,
2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
R. P.: Course and Prognosis in Amyotrophic Lateral Sclerosis, Arch. Neural. 8: 117-127. 1963. Koerner, D. R. : Amyotrophic Lateral Sclerosis on Guam: A Clinical Study and Review of the Literature, Ann. Intern. Med. 37: 1204-1220, 1952. Lawyer, T., and Netsky, M. G.: Amyotrophic Lateral Sclerosis, Arch. Neurol. Psychiatr. 69: 171-192. 3953. Bosma, J. F.iProgressive Motor Disabilities, Postgrad. Med. 49: 162-166, 1971. Hirano, A., Kurland, L. T., and Sayre, G. P.: Familial Amyotrophic Lateral Sclerosis, Arch. Neurol. 16: 232-243, 1967. Brody, J. A., Hirano, A., and Scott, R. M.: Recent Neuropathologic Observations in Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia of Guam, Neurology 21: 528-536, 1971. Reed, A. C.: Nervous Diseases in China, Boston Med. Surg. J. 171: 638, 1914. Guyton, A. C.: Medical Physiology, ed. 4, Philadelphia, 1971, W. B. Saunders Company, p. 678. Aran, F. A.: Recherches sur une maladie non encore decrite du systeme musculaire, Arch. Gen. Med. 24: 5, 1850. Duchenne, G. B.: Recherches faite8 a laide du galvanisme sur letat de la contractilite et de la sensibilite, electromusculaires dans les paralyses des membres superieurs, C. R. Acad. Sci. 29: 667-670, 1849. Charcot, 3. M., and Joffrov. A.: Deux cas datronhie museulaire nropressive avee lesions de la substance grise et des-faisceaux antero-lateiaux de la moelie epiniere, Arch. Physiol. Norm. Path. 2: 354, 744, 1869. Grinker, R. R. and Balm, A. L.: Neurology, ed. 6, Springfield, 1966, Charles C Thomas Publisher. DR. 12881296. Wintrobe, M. W.: Harrison’s Principles of Internal Medicine, ed. 6, New York, 1970, McGraw-Hill Book Company, Inc., p. 1830. Alpers, B. J., and Farmer, R. A.: Role of Repeated Trauma by Pneumatic Drill on the Induction of Amyotrophio Lateral Sclerosis, Arch. Neurol. Psych&r. 62: 178-182, 1949. Wechsler, I. S, Sapirstein, M. R., and Stein, A.: Primary and Symptomatic Amyotrophic Lateral Sclerosm; a Clinical Study of 81 Cases, Am. J. Med. Sci. 208: 70-81, 1944. Brown, I. A.: Chronic MercuriaIism, Arch. Neural. Psychiatr. 72: 674-681, 1954. Brain, R.: Clinical Neurology, ed. 1, London, 1960, Oxford University Press, pp. 356-358. Forster, F. M., and Alpers, B. J.: Site of Origin of Fasciculations in Voluntary Muscle, Arch. Neurol. Psychiatr. 61: 264-267, 1944. Bing, R., Gehirm, and Ruckenmacks: Diagnostik, ed. 7, Berlin, 1927, Urban und Schwarzenberg. Elliott, H. C.: Textbook of Neuroanatomy, ed. 2, Philadelphia, 1969, J. B. Lippincott Company, p. 142. Gold, G. N.: Temporomandibular Joint Dysfunction in Myotonic Dystrophy, Neurology 16: 212-216, 1966. Walton, J. H.: Essentials of Neurology, ed. 2, Philadelphia, 1961, J. B. Lippincott - .A *en company, pp. 14w13~. Liversedge, L. A., Swinburn, W. R., and Yuill, G. M.: Idoxuridine and Motor Neurone Disease, Br. Med. J. 1: 755756, 1970. Percy, A. K., Davis, L. E., Johnston, D. M., and ~Drachman, D. B. : Failure of Isoprinosine in Amyotrophic Lateral Sclerosis, N. Engl. J. Med. 286: 689, 1971. Brown, W. A., and Mueller, P. S.: Psychological Function in Individuals With Amyotrophic Lateral Scleroeis, Psychosom. Med. 32: 141-152, 1970.
Reprint
requests
to:
Dr. Neal W. Roller 3606 Gillham Rd. # 21 Kansas City, MO. 64111
OF ORAL
MEDICINE,
PHILADELPHIA
AND
GENERAL
MEDICINE, DEPARTMENT
UNIVERSITY OF DENTAL
OF PENNSYLVANIA RESEARCH,
SCHOOL
OF
THE
HOSPITAL
Amyotrophic lateral sclerosis, a type of motor neuron disease, is a uniformly fatal neurologic disorder characterized by inexorably progressive destruction of upper and lower motor neurons. The disease is of interest to dentists because patients with motor disability involving the mouth and pharynx may initially seek dental consultation. This article presents a case of amyotrophic lateral sclerosis with predominantly bulbar involvement. The mode of clinical presentation and the management of the patient with motor neuron disease are discussed.
V
arious reports list dysarthria and/or dysphagia as the presenting complaint of 9 to 26 per cent of all patients with motor neuron disease.1-3 Bosma4 has stressed that some entities of progressive motor impairment are most clearly identified in the oral and pharyngeal regions. Almost all patients eventually show oral or pharyngeal involvement. Because these initial complaints are so closely linked with the functioning of the mouth, it is reasonable to expect that many patients with motor neuron disease will consult their dentists. The proportion of patients who elect to consult dentists about these symptoms is unknown, as reports of motor neuron disease in the dental literature are virtually nonexistent. Amyotrophic lateral sclerosis (ALS) is a rare disease, most often seen in the classic sporadic form. However, two other types have been described: a type unique to the island of Guam and a type known as familial ALS.2* 5*E This article will be confined to a discussion of the classic form of ALS. An accurate estimate of the incidence of ALS has not been possible because it is so infrequently seen in the general population.2 Males are affected more These studies were supported by the Oral Medicine Research Training Program, 5TOlDE77, for the National Institute of Dental Research, NIH, to the Department of Dental Research, The Philadelphia General Hospital. *Postdoctoral Oral Medicine Trainee. **Associate in Oral Medicine. **‘Professor and Chairman, De artment of Oral Medicine, University of Pennsylvania School of Dental Medicine, and Chle4 of Dental Research, The Philadelphia General Hospital.
46
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Amyotrophic
lateral
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47
than females, in a rat.io of 2 :l. The insidious onset is usually in the fourth to the sixth decade, although it has been reported as early as age 14.7 The upper motor neurons, which constitute the corticospinal or pyramidal tract, arise from the principal motor area of the cortex, which is located in the posterior part of the frontal lobe immediately in front of the central sulcus. The most outstanding fibers in the corticospinal tract are the large myelinated fibers that originate in the giant Betz cells of the motor area and account for approximately 3 per cent of the total number of corticospinal fibers. The remaining fibers are smaller and only 60 per cent are myelinated.* Stimulation of the cells in the lower lateral part of the motor area causes bilateral movement in .the pharynx, larynx, face, and jaw, while stimulation of the midline and superior portion of this area causes movement in the legs, feet, and toes. As the corticospinal tract descends through the brain stem, it gives off fibers which travel to the contralateral motor nuclei of the cranial nerves. Below the medulla the major portion of the corticospinal fibers decussate to form the lateral corticospinal tract. The lateral corticospinal tract synapses with internuncial neurons ending on the anterior horn cells of the spinal cord. The final common path of motor activity is the lower motor neuron which transmits impulses from the anterior horn cells of the spinal cord and from the motor cells of the brain stem to the voluntary muscles. A lesion of the lower motor neurons will result in a diminished ‘tendon reflex, with weakness and wasting of the muscles (as seen in progressive bulbar palsy and progressive muscular atrophy), whereas a lesion of the corticospinal tract above the medulla will cause exaggerated reflexes and spastic muscles (as seen in pseudobulbar palsy). Amyotrophic lateral sclerosis is characterized pathologically by degenerative changes in the motor neurons involving the corticospinal tracts (upper motor neurons), the motor cells of the brain stem, and the anterior horn cells of the spinal cord (the lower motor neurons). Involvement of lower motor neurons alone was first described by Aran and Duchenne,lO who called the disease progressive muscular atrophy. Charcot and Joffroyll used the term amyotrophic lateral sclerosis to describe lower motor neuron lesions associated with corticospinal tract involvement. When the muscles innervated by the cranial nerves are affected primarily, the term progressive bulbar (pertaining to the medulla oblongata) palsy is often used. Pseudobulbar pa7sy, which affects the corticospinal tracts above the medulla, is differentiated from progressive bulbar palsy by spastic, as opposed to wasted, hypotonic muscles and by frequent impairment of voluntary control over emotion. All these entities describe motor neuron disease and differ from each other only in location of the primary lesion.2j 12~l3 ETIOLOGY Trauma, inflammation, toxic or heavy metal poisoning, metabolic disorders, viral infections, associated cancer, dietary deficiencies, vascular diseases, and stress have all been suggested as etiologic or contributing factors. In most reported cases, the relationship is doubtful and so far no conclusive evidence has been presented to document the cause of AI&. The most frequently cited etiologic agent is trauma.2 Alpers and Farmerl* are among the authors who have supported trauma as the etiologic factor, but
48
Roller et al.
Oral Surg. .January,
1974
most other authors find no relationship to trauma.‘j BrownI reported one case of ALS in a farmer suffering from chronic mercury poisoning. Studies on Guam failed to show an increased incidence in the military population stationed on the island during World War II and did not support an environmental or infectious agent. as the etiologic factor.6 CLINICAL PICTURE The nature of the earliest symptoms of amyotrophic lateral sclerosis depends upon the region of the nervous system first affected. Koerner,2 in a survey of thirty-five cases, noted initial spinal involvement in twenty-seven cases, initial bulbar involvement in three, and a combination of spinal and bulbar involvement in five cases. Mackay,l in a total of seventy patients, noted spinal onset in forty-four, bulbar onset in eleven, and a combination in fifteen. Anterior motor neuron degeneration is usually first seen as muscular wasting in the hands, especially in the muscles of the thenar eminences. The patient may be conscious of weakness, stiffness, or clumsiness of movements of the fingers. Often asymmetric initially, the weakness and muscular wasting gradually becomes symmetric and widespread. I7 The lower limbs are usually less affected than the upper limbs, with weakness of the legs seen only in later stages of the disease. Fasciculation is a prominent symptom. This involuntary contraction of groups of muscles, apparent through intact skin, has been considered evidence of disease of the anterior horn cell.‘* The disease will eventually, if not initially, affect the nuclei of the cranial nerves, The hypoglossal nucleus is the most commonly affected; fifty of fiftythree cases in one study3 and thirty-one of thirty-five in another2 showed involvement of the twelfth cranial nerve. The tongue shows conspicuous symmetrical fasciculations and eventually muscular atrophy. Protrusive movements of the tongue are at first weak and later lost. There is often an associated paresis of the orbicularis oris. Bing and associates I9 believe that the uppermost part of the hypoglossal nucleus contributes fibers to the facial nerve, which may explain the occurrence of this weakness of the orbicularis oris even when the facial nerve is otherwise unaffected. The nucleus ambiguus, composed of cranial nerves IX and X and some fibers from XI, is the next most frequently affected. It, supplies motor fibers to the soft palate, pharynx, and larynx. The glossopharyngeal (IX) has minimal motor function, supplying the stylopharyngeus and possibly the superior constrictor of the pharynx. Because the vagus (X) supplies the main motor innervation to these same muscles, it is clinically difficult to test the motor function of IX.2o Thus, when one is considering the nerve supply to the soft palate, pharynx, and larynx, the vagus is the cranial nerve tested clinically and is mainly responsible for the clinical manifestations. In ALS involving the vagal nuclei, the soft palate is atrophic and motionless and hangs low. With advancing disease, coughing and swallowing become difficult and regurgitation of fluids and foods through the nose is frequent. Ultimately, the patient cannot yawn, sniff, hum, or blow his n0se.l’ Speech suffers as a result of paresis of the lips, tongue, and palate and becomes slurred and then unintelligible. The vocal cords may be paretic or
Amyotrophic
lateral
sclerosis
49
paralyzed. The voice then becomes hoarse, and eventually the patient is aphonic. Involvement of the spinal accessory motor nuclei (XI) results in weakness and fasciculations of the upper trapezius and sternomastoid muscles. There is a tendency for the head to fall backward since both sternomastoids flex the head forward. When the seventh and fifth cranial nuclei are affected, the muscles of mastication are weakened, chewing becomes difficult, and there is often severe malocclusion. In the late stages of the disease, the mandibular inserting muscles may become extremely weak, requiring manual support of the jaw. Temporomandibular joint dysfunction, evidenced by dislocations, instability, and bilateral hypermobility, is sometimes present.21 The nuclei of the third, fourth, and sixth cranial nerves are usually spared. Examination of reflexes is important in evaluating a patient suspected of having a motor neuron disease. In disease states, the various alterations of deep tendon reflexes indicate the. location of pathologic processes along the reflex arch pathway. Degeneration of the lower motor neurons causes hyporeflexia ; corticospinal degeneration leads to hyperreflexia. Corticospinal tract lesions in or above the upper brain stem can be tested by the jaw jerk. This reflex is elicited by means of a sharp downward tap on the chin with the mouth held partly open. Exaggerated contraction of the masseter muscles indicates a positive diagnosis.22 With involvement of the vagus motor nuclei by ALS, the palatal and pharyngeal reflexes may be depressed. The normal palatal reflex produces arching of the soft palate when it is softly touched. The pharyngeal or gag reflex is produced by touching the posterior pharyngeal wall. The motor function of the vagus, trigeminal, and hypoglossal nerves can also be tested by the swallowing reflex. There are additional reflexes which are of value in the diagnosis of corticospinal tract lesions. The extensor plantar reflex (Babinski) is virtually diagnostic of a lesion of the corticospinal tract at any point in its course from the motor cortex down through the brain stem.22 Also useful in diagnosis is the abdominal reflex, which, while normally decreased in corticospinal tract degeneration, is for some reason preserved until late in the course of ALS. The sphincters in ALS are usually minimally affected. DIAGNOSIS
Motor neuron disease, in its later stages, can be diagnosed with reasonable confidence.12 Progressive muscle atrophy and muscle fasciculation, no sensory loss, and some evidence of corticospinal tract disease should stimulate further neurologic investigation. Laboratory test findings are usually within normal limits or, if altered, are usually abnormal as a result of intercurrent disease. PROGNOSIS
Amyotrophic lateral sclerosis is a fatal disease with varying rates of progression, depending on the sites of degeneration. Life expectancy in patients with predominantly lower motor neuron involvement is from 3 to 5 years; however, bulbar involvement decreases the expectancy to 2 to 3 years. Bulbar involvement causing respiratory difficulties leading to aspiration pneumonia is the usual proximate cause of death.
50
Roller
et al.
Oral Surg. .January,
1974
TREATMENT
The approach to treatment of amyotrophic lateral sclerosis has been as varied as the reported etiologic factors. Antiviral agent6 24 and various ritamins have been tried, but the results have been uniformly discouraging. The only treatment is supportive care. Tricyclic antidepressants have been helpful in many cases, as it is likely that there exists a severe underlying depression2” CASE REPORT A 59.year-old male dentist was referred to the Oral Medicine Clinic of Philadelphia General Hospital with a chief complaint of inability to speak clearly and difficulty in eating and swallowing. The patient’s professional associates and family first began noticing a slurring of his speech approximately ll$ years prior to presentation. The speech difficulty progressively worsened. On presentation, it was difficult for the patient to communicate orally, and written remarks were necessitated. Eating firm food and taking liquids caused choking, and at times food was forcefully ejected, occasionally through the nose, but without aspiration. Eating a sandwich could take up to s hour. Saliva accumulated in the mouth, and the patient drooled from the corner of the mouth, especially during sleep. The patient had noticed muscular faciculations in the shoulder. No inappropriate emotional responses were reported. There was no loss of or aberrations in taste. No painful or sensitive areas were reported. Except for dysphagia, the patient had no difficulty practicing his profession, and he continued to work a full schedule. The medical history was unremarkable. There was no family history of neurologic disorders, including poliomyelitis. Drug allergies or exposure to heavy metals or toxins were denied. No head or neck injuries were reported. There was no history of recent falls or loss of balance. The patient had discontinued smoking many years ago and had recently discontinued all alcohol consumption. No sphincter disturbances were reported. During the last several months the patient had sought consultations with a speech therapist, a dentist, and a neurologist. The patient reported the examinations as nonrevealing and not helpful. Bite-positioning appliances had been constructed to correct a faulty occlusion, and the patient had been instructed in tongue-strengthening exercises. Physical examination revealed a well-developed, moderately thin, alert, intelligent, and cooperative patient. No disturbances in gait were noted. No loss of memory or recall was observed. Blood pressure was 140ho; the pulse was 76 and regular; and oral temperature was 98.8” F. The platysma, sternomastoid, pectoralis, biceps, and trapezius muscles showed fasciculations that could be especially elicited upon gentle tapping. Gross testing revealed that there was no muscle weakness, and strength was symmetrically equal. The pupils were equal and reacted to light and accommodation. No papilledema, nystagmus, or retinovascular changes were noted. The optic discs were flat. Examination of the cranial nerves was nonrevealing except for the hypoglossal, vagus, and spinal accessory. The speech was nasal and almost incomprehensible. Air audibly escaped through the nose during normal breathing.
The jaw jerk was moderately active; absent. The plantar response was flexor. and symmetrical in all areas tested.
the gag and pharyngeal reflexes were completely The abdominal and tendon reflexes were normal
Oral examination The most impressive finding on oral examination was that of muscular fasciculations, most obvious in the tongue but also observed in the orbicularis oris and the pharyngeal muscles. An occasional fasciculation was noted in the masseters, but the muscles of mastication did not show atrophy or noticeable weakness. The weakness of the orbieularis oris was
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demonstrated by an inability to whistle or purse the lips. The tongue was lobulated and slightly enlarged in size, with a notable restriction in protrusive movements plus inability to elevate and extend laterally. The mouth was free of mucosal lesions. The teeth were adequately restored and showed evidence of recent occlusal equilibration. Copius foamy saliva was pooled in the floor of the mouth and in the mandibular labial vestibule. The periodontium was healthy. Attempts to consecutively reproduce a centric jaw relationship failed. The patient’s history and physical findings indicated a motor neuron disease. A diagnosis of amyotrophic lateral sclerosis with predominantly bulbar involvement was suspected and later was confirmed by consultation with a neurologist. The following recommendations were made : 1. Continue part-time work, with adequate periods of rest. 2. Avoid exposure to infections, especially respiratory infections. At the first sign of infection, immediately obtain medical attention. 3. Maintain nutrition by a semisolid diet, best obtained with the use of a blender. 4. Continue on a program of moderate exercises, including tongue exercises. 5. On a regular basis have medical checkups, especially if there is increased difficulty in swallowing or eating. Six months after the initial visit a gastrostomy was performed but was not comfortable, and later an esophagostomy was better tolerated. There was increasing respiratory difficulty, medications were complicated by inability to swallofv accumulated saliva. Anticholinergic helpful in reducing salivary secretions.
DISCUSSION The patient with motor disabilities that involve the oral and pharyngeal regions may first seek consultation with a dentist. It is important for the dentist to recognize a progressive motor disability and not attempt to manage the condition without an understanding of the nature and severity of the disease. Treatment of a malocclusion or muscular weakness without knowing the cause of the symptoms would be a disservice to the patient. If a motor disability is suspected, it is imperative that a neurology consultation be obtained. Management of the complications of the disease requires the close cooperation of dentist and physician. The dentist must also be aware that he may be consulted by a patient whose disease has been correctly diagnosed and is seeking another, more reassuring opinion. Brown and Mueller,25 in evaluating the psychologic make-up of ten patients with ALS, noted that many of them had achieved vocational and financial success, were independent, and were highly competent. Many believed that they could “beat” the disease and went to extremes to continue in a semblance of their accustomed life styles. Some denied the disease, expressing little concern over the “disease Lou Gehrig had.” Patients of this type could be tempted to start on a protracted search for a nonexistent cure for their disease. The patient may not be satisfied that there is no effective treatment and go to considerable expense and effort in attempting to find help. Of concern to the dentist or physician is the type of patient mentioned above who may be tempted to seek advice from a paraprofessional who may offer inappropriate therapy while the patient’s condition is deteriorating. SUMMARY When the onset of amyotrophic lateral sclerosis is predominantly origin, the patient may first consult a dentist because of the oral-facial
bulbar, in symptoms
52
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1974
of dysphagia, dysarthria, and muscular weakness. The diagnosis can be reasonably ascertained from it simple neurologic examination, and this should cause the dentist to recommend a neurology referral. It is stressed that some of these patients may also visit the dentist seeking an alternative diagnosis, in which case the dentist has a responsibility to the patient to prevent him from continuing a search for a cure that is not at this time to be found. REFERENCES 1. Mackay,
2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. 25.
R. P.: Course and Prognosis in Amyotrophic Lateral Sclerosis, Arch. Neural. 8: 117-127. 1963. Koerner, D. R. : Amyotrophic Lateral Sclerosis on Guam: A Clinical Study and Review of the Literature, Ann. Intern. Med. 37: 1204-1220, 1952. Lawyer, T., and Netsky, M. G.: Amyotrophic Lateral Sclerosis, Arch. Neurol. Psychiatr. 69: 171-192. 3953. Bosma, J. F.iProgressive Motor Disabilities, Postgrad. Med. 49: 162-166, 1971. Hirano, A., Kurland, L. T., and Sayre, G. P.: Familial Amyotrophic Lateral Sclerosis, Arch. Neurol. 16: 232-243, 1967. Brody, J. A., Hirano, A., and Scott, R. M.: Recent Neuropathologic Observations in Amyotrophic Lateral Sclerosis and Parkinsonism-Dementia of Guam, Neurology 21: 528-536, 1971. Reed, A. C.: Nervous Diseases in China, Boston Med. Surg. J. 171: 638, 1914. Guyton, A. C.: Medical Physiology, ed. 4, Philadelphia, 1971, W. B. Saunders Company, p. 678. Aran, F. A.: Recherches sur une maladie non encore decrite du systeme musculaire, Arch. Gen. Med. 24: 5, 1850. Duchenne, G. B.: Recherches faite8 a laide du galvanisme sur letat de la contractilite et de la sensibilite, electromusculaires dans les paralyses des membres superieurs, C. R. Acad. Sci. 29: 667-670, 1849. Charcot, 3. M., and Joffrov. A.: Deux cas datronhie museulaire nropressive avee lesions de la substance grise et des-faisceaux antero-lateiaux de la moelie epiniere, Arch. Physiol. Norm. Path. 2: 354, 744, 1869. Grinker, R. R. and Balm, A. L.: Neurology, ed. 6, Springfield, 1966, Charles C Thomas Publisher. DR. 12881296. Wintrobe, M. W.: Harrison’s Principles of Internal Medicine, ed. 6, New York, 1970, McGraw-Hill Book Company, Inc., p. 1830. Alpers, B. J., and Farmer, R. A.: Role of Repeated Trauma by Pneumatic Drill on the Induction of Amyotrophio Lateral Sclerosis, Arch. Neurol. Psych&r. 62: 178-182, 1949. Wechsler, I. S, Sapirstein, M. R., and Stein, A.: Primary and Symptomatic Amyotrophic Lateral Sclerosm; a Clinical Study of 81 Cases, Am. J. Med. Sci. 208: 70-81, 1944. Brown, I. A.: Chronic MercuriaIism, Arch. Neural. Psychiatr. 72: 674-681, 1954. Brain, R.: Clinical Neurology, ed. 1, London, 1960, Oxford University Press, pp. 356-358. Forster, F. M., and Alpers, B. J.: Site of Origin of Fasciculations in Voluntary Muscle, Arch. Neurol. Psychiatr. 61: 264-267, 1944. Bing, R., Gehirm, and Ruckenmacks: Diagnostik, ed. 7, Berlin, 1927, Urban und Schwarzenberg. Elliott, H. C.: Textbook of Neuroanatomy, ed. 2, Philadelphia, 1969, J. B. Lippincott Company, p. 142. Gold, G. N.: Temporomandibular Joint Dysfunction in Myotonic Dystrophy, Neurology 16: 212-216, 1966. Walton, J. H.: Essentials of Neurology, ed. 2, Philadelphia, 1961, J. B. Lippincott - .A *en company, pp. 14w13~. Liversedge, L. A., Swinburn, W. R., and Yuill, G. M.: Idoxuridine and Motor Neurone Disease, Br. Med. J. 1: 755756, 1970. Percy, A. K., Davis, L. E., Johnston, D. M., and ~Drachman, D. B. : Failure of Isoprinosine in Amyotrophic Lateral Sclerosis, N. Engl. J. Med. 286: 689, 1971. Brown, W. A., and Mueller, P. S.: Psychological Function in Individuals With Amyotrophic Lateral Scleroeis, Psychosom. Med. 32: 141-152, 1970.
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