SEGMENTAL MYOCLONUS AND BASILAR ARTERY GIANT ANEURYSM CASE R E P O R T

J.

PITÁGORAS DE MATTOS * — ANA L. ZUMA DE ROSSO ** EDUARDO ZAYEN ** — SÉRGIO A. P. NOVIS ***

S U M M A R Y — A 70 years-old man w a s admitted at our hospital because of unstable angina pectoris. He had essential hypertension and right h e m i p l e g i a f r o m a ischemic s t r o k e t w o years before admission. On neurologic examination, it w a s found mental disorientation, unstable emotionality, right spastic hemiparesis with right Babinski sign, and segmental m y o c l o n u s a f f e c t i n g t h e s u p e r i o r lip a n d the p a l a t e ( p a l a t a l n y s t a g m u s ) o n the r i g h t s i d e . On the C T scan, a g i a n t a n e u r y s m o f the b a s i l a r a r t e r y w a s d e t e c t e d . W e c o n c l u d e t h a t the s e g m e n t a l m y o c l o n u s c o u l d b e e x p l a i n e d b y i s c h e m i c l e s i o n s i n the G u i l l a i n - M o l l a r e t t r i a n g l e . KEY WORDS:

segmental

myoclonus,

palatal

nystagmus,

basilar artery

aneurysm.

Mioclonia segmentar e aneurisma gigante da arteria basilar. R E S U M O — Os autores se referem ao caso de um h o m e m de 70 anos, hipertenso e coronariopata, q u e a p r e s e n t a r a , d o i s a n o s antes, h e m i p l e g i a d i r e i t a c o m o c o n s e q u ê n c i a d e a c i d e n t e vascular encefálico i s q u é m i c o . O exame n e u r o l ó g i c o , na vigência da internação hospitalar, mostrou desorientação espacial, instabilidade emocional ( c h o r o i m o t i v a d o ) , hemiplegia c o m sinal de Babinski à d i r e i t a e m i o c l o n i a s e g m e n t a r c o m p r o m e t e n d o o l á b i o s u p e r i o r e o p a l a to (nistagmo palatal) à direita. A t o m o g r a f i a c o m p u t a d o r i z a d a do crânio revelou aneurisma g i g a n t e da artéria b a s i l a r . C o n c l u i m o s q u e a m i o c l o n i a s e g m e n t a r p o d e r i a estar r e l a c i o n a d a às lesões isquémicas no triângulo de Guillain-Mollaret. P A L A V R A S - C H A V E : m i o c l o n i a s e g m e n t a r , n i s t a g m o palatal, a n e u r i s m a dia a r t é r i a basilar.

The first reference in the literature about myoclonic jerk was made by Friedreich, in 1878, naming the abnormal movement as «paramyoklonus multiplex)^. Presently, the myoclonus is classified according to its distribution as focal, segmental, multifocal and generalized 5. We report on a case of segmental myoclonus (soft palate and lips). During the investigation it was found to be associated to a basilar artery aneurysm. A discussion about probable mechanisms of the palatal myoclonus is provided. CASE

REPORT

J R ( R e g 223619-7, H U C F F - U F R J ) , a 7 0 y e a r s - o l d n e g r o m a n , w a s a d m i t t e d a t o u r hospital because of unstable angina pectoris. He had essential hypertension and right hemiplegia from a ischemic stroke t w o years before admission. On neurologic examination, it w a s found mental disorientation, emotional unstability, right spastic hemiparesis with right Bab i n s k i ' s s i g n , a n d s e g m e n t a l m y o c l o n u s a f f e c t i n g the s u p e r i o r a n d i n f e r i o r l i p s a n d t h e p a l a t e (palatal n y s t a g m u s ) o n t h e r i g h t side.. O n the C T scan, a g i a n t a n e u r y s m o f the b a s i l a r a r t e r y was detected as well as ischemic lesions a n d cerebral atrophy ( F i g s . 1 and 2 ) . Because of his severe c a r d i o v a s c u l a r d i s e a s e the a n g i o g r a p h i c s t u d y w a s n o t p e r f o r m e d .

Departmment of Neurology, Clementino Fraga Filho University Hospital ( H U C F F - U F R J ) , R i o d e J a n e i r o : * A s s o c i a t e d P r o f e s s o r ; * * N e u r o l o g i s t ; *** H e a d o f t h e S e r v i c e o f N e u r o l o g y . Dr. James Pitágoras de Mattos — Av. Fax (5521) 2673996.

São Sebastião 165/101

- 22291 Rio de Janeiro

RJ

- Brasil.

COMMENTS

Segmental myoclonus is characterized by myoclonic jerks affecting two or more contiguous or adjacent muscles . Aetiologically, it can be divided in essential and symptomatic forms . Regarding to palatal myoclonus the symptomatic form is more frequent, according to the extensive review of the literature made by Deuschl et al. in 1990. They reviewed 287 cases of palatal nystagmus of which only 27% were essential. In the symptomatic group (73%), 40% were due to cerebrovascular disease, 8% to trauma, 7% to neoplasia, 3% to multiple sclerosis, 2% to degenerative disease and 2% to encephalitis. According to Jankovic and Pardo , infarction and hemorrhage of the brainstem were the main pathological cause of palatal myoclonus. It is admitted that palatal myoclonus is secondary to a disruption of the dentato-rubro-olivary pathway, known as the Guillain-Mollaret triangle " . The unilateral palatal nystagmus arises from a lesion in the ipsilateral dentate nucleus or in the contralateral central tegmental tract and may be associated with a hypertrophic degeneration of the contralateral inferior olive . . Furthermore, the only abnormal movement associated with lesion of the inferior olive is palatal nystagmus . 5

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The challenge of this case is to know whether the aneurysm is responsible direct or indirectly for the myoclonus or it is merely a radiological finding. It seems reasonable that they are related to each other once the cerebrovascular disease is the most frequent cause of the palatal nystagmus and the GuillainMollaret triangle is closely related with this involuntary movement. What should be the mechanism by which the aneurysm has induced the involuntary movement: ischemia or mass effect? Teasdall^, in 1958, described a similar case on which he demonstrated by angiography a posterior fossa arteriovenous aneurysm in which there was thrombosis of the right vertebral artery. Three months after the ictus, palatal nystagmus was substituted by right soft palate palsy. In that occasion, Teasdall has related the myoclonus with the vascular thrombosis. The direct (ischemic areas on the CT scan, angina pectoris) and indirect signs of diffuse atherosclerosis in our patient, together with the presence of a giant aneurysm of the vertebro-basilar system, suggest brainstem ischemic lesions and not a compressive effect as the probable cause of segmental myoclonus. REFERENCES 1. Deuschl G, Mischke G, Schenck E, Schult-Mônting J, Lucking CH. Symptomatic and essential rhythmic palatal myoclonus. Brain 1990, 113:1645-1672. 2. Jankovic J, Pardo R. Segmental myoclonus: clinical and pharmacologic study. Arch Neurol 1986, 43:1025-1031. 3. Kissel P, Schmitt J, Andre JM. Syndromes du tronc cérébral. Ehcycl Méd Chir Système Nerveux 7-1975, 17039A10, Paris: Editions Techniques, 1975. 4. Lee RG. The pathophysiology of essential tremor. In Marsden CD, Fahn S (eds) : Movement Disorders 2. London: Butterworths, 1987, p 423-437. 5. Patel VM, Jankovic J. Myoclonus. In Appel SH (ed) : Current of Neurology. Chicago: Years Book Med Publ, 1988, p 109-156. 6. Teiasdall RD. Posterior fossa arteriovenous aneurysm with occlusion of a vertebral artery. Neurology 1958, 8:571-574.

Segmental myoclonus and basilar artery. Giant aneurysm. Case report.

A 70 years-old man was admitted at our hospital because of unstable angina pectoris. He had essential hypertension and right hemiplegia from a ischemi...
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