Myotonic dystrophy—Sedative and anesthetic management

Myotonic dystrophy-Sedative and anesthetic management Cy Wa.ld, D.M.D., Bronx, X. Y. DIVISION OF DENTISTRY, RETARDATION

ROSE F. KENNEDY

AND HUMAN

DEVELOPMENT

CENTER FOR MENTAL (HAROLD

DINER,

D.D.S., DIRECTOR)

Myotonic dystrophy is a disorder of widespread dimension, with numerous oral and facial anomalies making it of special interest to the dentist. Because of the and consideration are multisystem involvement of this disease, careful evaluation required for those patients whose dental needs dictate the use of sedative or ambulatory general anesthetic management. Two cases illustrate these points.

D

ystrophia myotonica is a steadily progressive muscular disorder, familial in nature. The disease is usually transmitted as a mendelian dominant, and the phenomenon of anticipation is quite often present; that is, the children arc affected at an earlier age than the parents and are more likely to exhibit the fully developed syndr0me.l Perhaps the earliest and most consistent finding is that of myotonia-a delayed relaxation following voluntary muscle contraction. An abnormal hand grasp may first characterize this symptom.” The myotonia may bc slight, barely discernible, and persist for several years as the sole manifestation of the disease. Then, muscle wasting and weakness inevitably follow. Numerous associated anomalies make myotonic dystrophy a true multisystem disease. Of the dystrophic changes, cataract is the most common. Premature frontal baldness and testicular atrophy are very common in males. Women may have a variety of disorders of ovarian function, such as amenorrhea, dysmenorrhea, and ovarian cysts. Mental retardation and deterioration are consistently reported.5 Myotonic dystrophy is thought of as a disorder that has its onset in young adulthood-usually the second or third decade. The onset is usually insidious but on occasion, as seen in other neuromuscular disorders, an episode of acute stress, such as fright, trauma, or illness, may precipitate or uncover the first symptoms. 886

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~~yotonic dystrophy

Fig. 1. Typical “myopathic musculature, and open-bite.

CRANIOFACIAL

AND

ORAL

f&es.”

Note

ptosis,

temporalis

wasting,

flaccid

887

facial

MANIFESTATIONS

Facial muscles are most characteristically affected, causing a “mvopathic facies” (Fig. 1). The weakness of facial muscles causes a smoothing out of the usual grooves, leaving a blank expression. Ptosis due to weakness of the levator palpebrae muscles is frequently noted. On voluntary movement of the face (baring the teeth or smiling), there is an updrawing of the corners of the mouth with wrinkling of the upper lip. This gives a snarling or sneering myopathic appearance which is characteristic.” Involvement of muscles of mastication develops early in some cases. Evidence of myotonia may be noticed on biting hard or on chewing vigorously. A sense of tightness may be experienced at the angles of the jaw. Temporalis wasting causes a. symmetrical hollowing of the temporalis fossae and allows the jaw to be slung forward, producing a characteristic “hatchet face.“” Dislocation of the jaw may occur as a result of weakness. Involvement of muscles of deglutition is rarely observed except in terminal stages, when choking may be a real threat to life. As a result of weakness of “bulbar muscles,” speech difficulties (nasality) and accumulation of saliva ma> be a problem in the terminal stage of the disorder. The soft palate has been noted to be extremely thin, and paresis of vocal cords has also been reported.2 Caughey’ has noted a large percentage (69 per cent) of radiographic abnormalities in the skull films of adults with long-standing mpotonic dystrophy. A general thickening of all or part of the calvarium, hypcrostosis cranii (bony, cxostoses of frontal and parictal bones), a small pituitary fossa, a general increase in air sinuses with pneumatization of the dorsum sclla, and prognathism are the most consistent abnormalities” (Fig. 2).

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Oral Burg. June, 1975

Wald

Fig. 8. Lateral head plate of B. K.‘s Zl-year-old sibling. sinuses, prognathic mandible, exostoses of frontal bones.

Note

dense calvarium,

large

Many of these changes are apparently related to endocrine problems; that is, these patients manifest diminished androgenie functions of the gonads and the adrenal cortex. Thus, the usual restraining influence (negative feedback) of the androgcns on pituitary growth hormone is absent, leading to acromegaloidlike changes.” As far as specific dental aberrations arc concerned, malocclusions, spacing, posterior cross-bites, and anterior open-bites arc most frequently reported. Several investigators, ?, I13I4 have attributed t.hese to the muscular imbalance arising from loss of muscle function of certain groups (lips, cheeks) in disproportion to others (tongue). CASE REPORTS CASE Clinical

1 history

H. I(., an 11.year-old Caucasian boy, was referred for routine diagnostic services by the Association for the Help of Retarded Children. The child had no significant dental complaints and no previous dental experience. Oral

examination

Oral examination revealed a markedly carious mixed tlentition with numerous deciduous tooth remnants and nonvital asymptomatic mandibular permanent first molars. Oral hygiene IVXS extremely poor, with generalized cervical green stain and abundant calculary deposits. Soft tissues were within normal limits with the exception of a large, fissured, almost bilobed tongue and a generalized marginal gingival inflammation (Fig. 3). The patient had XII anterior open-bitt, probably secondary to the macroglossia, as well as tongue-thrust and mouth-breathing habits. Radiographic examination revealed congenital absence of all permanent cuspids and premolnrs, with the exception of the maxillary left premolar. A fractured mrsiodens was also noted. Medical

history

Of significance in the medical history was the presence of myotonic gross motor coordination remained basically intact, although the child lethargic, walked with a shuffling gait, and was limited in the range

dystrophy. Fine and was markedly obese, of his activities. He

Myotonic

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Fiy. 3. 8, Myopathic appearance of first patient tongue, cervical green stain, and fractured mesiodens.

(B. Ii.).

dystrophy

B, IYote macroglossia,

889

fissured

demonstrated ptosis, cataracts, and the typical facies of the syndrome. No cardiorespiratory compromise was reported. The child was severely retarded (testing with a mental age of 2 to 3), although he appeared affable and minimally resistant at initial presentation. course Routine complete blood count, urinalysis, and pediatric clearance were obtained prior to two outpatient deep-sedative management sessions. On each occasion, the child was premeditated with 100 mg. intramuscular Vistaril along with 0.4 mg. atropine. The patient was maintained with 10 mg. intravenous Valium, nitrous oxide and oxygen (3 L/M : 3L/M), and increments of 0.5 per cent Brevital for instances of intermittent agitation. For all operative procedures, 3 per cent Carbocaine local anaesthesia was used. Sedative sessions were uneventful, and all necessary restoratiw, surgical, and periodontal treatments were performed.

Treatment

CASE

2

L. V. was a 13M-year-old Puerto Rican girl with myotonic dystrophy. She had no previous dental experience and presented extreme behavioral wsistancr. Multiple retained deciduous teeth and marked carious breakdown were observed. Past

medical

history

The patient had an episode of hypoxia due to suffocation at the age of 6 months, after which there was a regression of development and subsequent psychomotor retardation. When she was 7 years old, her brother was diagnosed as having myotonic dystrophy. A subsequent evaluation found her to have some weakness and difficulty releasing clenched fingers. Temporalis wasting was also noted. The results of an electromyogram and muscle biopsy were within normal limits, but the tentative diagnosis of myotonie dystrophy was still made. An cllectrocardiogram in 1972 showed “slurring of S wave” in two precordial leads, indicating a “mild intraventricular conduction defect.” No further electrocardiograms were recorded. Treatment

course

and pediatric screening were performed. All Routine complete blood count, urinalyses, values xwre within normal limits except urinalysis, which showed many bacteria and 8 white

taken during tlrntal procedure tlrmonstrating Fig. 4. A, Electrocardiograph strip supmventricular txchycardia with ST depression at 270 per minute,. If. E:lcetroc~ardiograpliic Notcx run of ventricular strip taken in intensive care unit during period of patient’s agitation. tachycnrdia between arrows. blood ~11s p(‘r high-p0wc.r fic,lil. The patient’s scvrw ment~al rctardntion and agitat,ion dictated the USC of :L general anesthc~tic in management of tllr dental condition. At thcb initial session, anesthesia was intfuecd with F’luottiaut (0.5 to 1.5 pW cent) and nitrous osirlc* and oxygen (3 liters per minute : 3 liter5 p(‘r minutci). i&inten:tnrc~ w:is achieved with 0.5 per reut Fluothane and increments of ISrrvital. The andhetic course \\:ts unc?‘entful, vital signs remaintd stablf:, and ttlca patient c~c~rgcd quickly though agitated. Ten dental PStractions KUP p(‘rformetl, with rrstorative work deferred for a subsequent visit. At, the sc~ond session (I week later), nnesthesi:t was induct?1 with 200 mg. Kchminc IICl along with 0.4 mg. atrapine intramuscuhrly. Maintc~nancc~ was :Lc~complist~t~tl with 10 mg. intravenous Vdium, nitrous oxide :~nd oxygen (3 liters per minute : 3 liters pflr minute), and inmwxlCnts of 0.5% Rrc~vital totaling 50 mg.; 3 per cent Carl~ocaine for lot-al anesthesia was also used. Shortly, the patient, manifested a markrtl t:lrlrycxrdi:l (unresponsive to deepening of nnestll&a), alternating with periods of normal pulse rate tjut irregular rhythm by palpation. An rlcctroc:~rdiogr;~~~l p(,rformed during the proCeduri> rc~dxl periods of su~,r:tvcntricular tnchycardix of 270 per minute, alternating with ruus of norm:tl sinus rhythm (X0 to 140 per minute). At, the conclusion of the session, the pxtic>nt \\:Ls taken to the pcdixtric~ intensive care unit for cardiac monitoring.

111 the iutensive care unit the patient was in normal sinus rhythm except during periods of agitation (precipitated by attempts at examination), during which runs of suprnventriculnr

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tachycardia were observed. Several brief runs (5 to 6 beats) of ventricular tachycardia were also observed (Fig. 4). basically consisted All contingencies for cardiac support were prepared, but treatment of leaving the patient alone with maternal support. By evening she exhibited normal sinus rhythm (110 to 130).

DISCUSSION

The two patients illustrate the multifactorial components of myotonic dystrophy and the variety of physical and systemic factors which must be considered. The prime considerations in the first case were the patient’s physical stature and mental status (both direct expressions of the disease), as well as avoidance of compromise to respiratory function. B. K.‘s marked obesity, short stature, “no neck,” large tongue, and flaccid oral musculature made maintenance of an airway a real concern. Active involvement of the intercostal muscles as well as the diaphragm has been reported in myotonic dystrophy (though infrequently), and these patients are said to be unduly susceptible to respiratory infections.” The child’s presenting hematocrit (52 per cent) and hemoglobin (19 Gm. per cent) may have already been indicative of secondary polycythemia and pulmonary hypoventilation. For these reasons, and because the child was at least partially receptive, a more conservative approach (deep sedation) was chosen. This allowed for spontaneous, unassisted respirations and maintenance of protective reflexes in an otherwise well-sedated patient. 1~.V., on the other hand, presented a different picture. Her extreme agitation and behavioral resistance dictated a general-anesthetic course. The principal concern here was the integrity of the cardiovascular system, in view of the abnormal electrocardiographic finding of 1972. Although objective symptoms of cardiac problems are rare, a large percentage (85 per cent in one study) of these patients do manifest electrocardiographic disturbances of conduction or rhythm.6 Prolongation of PR interval and intraventricular conduction defects arc the most common anomalies, while atria1 arrhythmias (atria1 flutter and atria1 fibrillation) are less frequent.l” The first anesthetic session, with the patient under Fluothane, was uneventful, although the drug carries with it a potential hazard when used in this syndrome. It has been suggested that the peripheral vasodilation and subsequent postoperative shivering seen with fluothane map precipitate the myotonia 01 make it worse.12 This did not happen here. The marked arrhythmias of the second session are still not fully explained. The possibility of an idiosyncratic response to a cardiorespiratory stimulant (Ketaminc) superimposed on an abnormal (although “mild”) conduction system exists. The effect of the child’s agitation and hysteria on her cardiovascular system was very obvious in her immediate postoperative period. (How much of this response can be attributed to emergence from general anesthesia, postoperative sequelae of Ketamine, or the patient’s usual behavioral patterns is difficult to determine.) The possibility, then, of a “supertentorially” exag-

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Oral Burg. .Junr’, 1975

gerated affect upon cardiac rate and rhythm, prcopcratively and during induction, also exists. Numerous additional anesthetic eonsidcrations must be macle for the myotonic patient who is to undergo the “standard” inpatient general anesthetic management. FOP example, thiopentone (frequently used in induction techniques) has been regarded as contraindicated in dystrophia m~otonica. patients because of profound respiratory depression. I)undce” has pointed out that these patients are unduly sensitive to I’entothal sodium, with prolonged apnea and an abnormal degree of muscular relaxation frequently observed. He believes that the defect is in the muscles rather than the central nervous system. Tower’:’ adds that certain oxidative enzymes (some of which are involved in the detoxification of Yentothal sodium in the liver) are quantitatively deficient in patients with myotonic dystrophy. Other precautions are necessary as well. 8uccinylcholine is said to cause a relative1.v slow contraction of the muscles, followed by a protracted return t,o the initial position. Hypothermia, generally seen in patients under anesthesia, may enhance myotonia (especially seen in paramyotonia) .i Certain narcotics, especially fentanyl, may cause muscular rigidity.’ In conclusion, then, it is obvious that the multisystem involvement accompanying myotonic dystrophy may create potentially serious complications in the dental and anesthetic management of such patients. REFERENCES

ed. 14, New York, 1962, Appleton-Century-Crofts, pp. 1. Barn&t, Henry L.: Pediatrics, 996-99T. 2. Batten, F. E., and Bibb, H. P.: Myotonia Atrophica, Brain 32: 187, 1909. 3. Brown, J. C., and Losch, P. K.: Dental Occlusion in Patients With Muscular I)ystrophy, Am. J. Orthod. 25: 1040, 1939. 4. Caughey, J. E.: Radiological Changes in thrl Skull in Dystrophia Myotonica, Hr. Med. J. 1: 137, 1952. 5. Caughey, J. E., and Myrianthoupoulos, N. C. : Dystrophia Myotonica and Relntcxd Disorders, Springfield, Ill.,, 1963, Charles C Thomas Publisher. 6. Church, 8. C.: The Heart III Myotonic Dystrophy, Arch. Intern. Med. 119: 176, 196i. 7. Dalal, F. Y., Bennet, E. J., Prithvl, Raj P., and Lee, 1). G.: Dystrophia Myotonica: A Multisystem Disease, Can. Anaesth. Sot. J. 19: 436-444, 1972. 8. Dodge, Philip R., Gamstrop, Ingrid, Byers, Randolph K., and Russell, Patricia: Myotonic Dystrophy in Infancy and Children, Pediatrics 35: 3-19, 1965. 9. Dundee, J. W.: Thiopentonc in Dystrophia Myotonica, Curr. Res. Anaesth. 31: 257, 1952. 10. Lindsay, J., Jr.: Cardiovascular Manifestations of Myotonic Dystrophy, Med. Ann. D.C. 41: 351.353, 1972. 11. Thxyer, Harley H. and Crenshaw, John: Oral Manifcxstation of Myotonic Muscular Dystrophy, J. Am. Dent. Assoc. 72: 14051411, 1966. 12. Thiel, R. E.: The Myotonic Response to Suxamethonium, Br. J. Anaesth. 39: 815821, 1967.

13. Tower, 1). B., Peters, E. L., and Pogorelskii, M. A.: Nature and Significance of Pentosuria in Neuromuscular Disease, Neurology 6: 126, 1956. 14. White, R.. A., and Sackler, A. M.: Effect of Progressive Muscular Dystrophy on Occlusion, J. Am. Dent. Assoc. 49: 449, 1954. Beprint requests to: Dr. Cy Wald Division of Dentistry Rose F. Kennedy Center 1410 Pelham Parkway South Bronx, N. P. 10461