Bilateral Congenital Oculomotor Nerve Palsy in a Child With Brain Anomalies
W i l l i a m V. Good, M.D., A. James Barkovich, M . D . , Bonnie L. Nickel, M . D . , and Creig S. Hoyt, M . D .
We t r e a t e d a 3 - m o n t h - o l d b o y w i t h b i l a t e r a l congenital oculomotor nerve palsy in w h o m a magnetic resonance imaging scan demonstrat ed a d e v e l o p m e n t a l b r a i n a n o m a l y i n t h e r e gion of the basal ganglia. T h e pupil was nor mal on one side, and there was n o aberrant r e g e n e r a t i o n of t h e o c u l o m o t o r n e r v e . W e c o u l d find n o e v i d e n c e for a p e r i p h e r a l o c u l o motor nerve lesion. T h i s demonstrates that congenital oculomotor nerve palsy can be caused by brainstem disease. Embryologically, b a s a l g a n g l i a a n d o c u l o m o t o r n u c l e i d e v e l op at the same time, and t h e Edinger-Westphal nucleus develops later. Thus, pupil sparing does not exclude a central origin for congeni tal o c u l o m o t o r n e r v e p a l s y .
ISOLATED OCULOMOTOR NERVE PALSY in c h i l d r e n is u n c o m m o n c o m p a r e d to adults''^ a n d o f t e n c o n g e n i t a l in n a t u r e . T h e l o c a t i o n o f t h e l e s i o n causing the congenital oculomotor palsy has b e e n p r e s u m e d to b e in t h e p e r i p h e r a l n e r v e o n the basis of two clinical observations: aberrant regeneration of the oculomotor nerve occurs c o m m o n l y in c o n g e n i t a l a n d t r a u m a t i c cases*; and associated neurologic problems in children with oculomotor nerve palsy are uncommon,^ although this observation has been chal lenged.* We t r e a t e d a c h i l d w i t h c o n g e n i t a l , b i l a t e r a l o c u l o m o t o r p a l s y in w h o m a m a g n e t i c r e s o nance imaging scan showed aplasia of basal ganglia structures on one side. T h e small size of extraocular muscles innervated b y this nerve a l s o s u g g e s t s that o c u l o m o t o r n e r v e n u c l e u s Accepted for publication Jan. 2, 1991. From the Departments of Ophthalmology (Drs. Good and Hoyt) and Radiology (Dr. Barkovich), University of California, San Francisco, California. Dr. Nickel is in private practice in San Rafael, California. Reprint requests to William V. Good, M.D., 400 Par nassus Ave., A 704, San Francisco, CA 94143.
hypoplasia or aplasia was the cause o f this child's oculomotor palsy.
Case Report A 3 - m o n t h - o l d b o y w a s e x a m i n e d in c o n s u l t a t i o n at t h e U n i v e r s i t y o f C a l i f o r n i a , S a n F r a n c i s c o , for e x o t r o p i a a n d b i l a t e r a l b l e p h a r o p t o sis. T h e r e was n o history o f birth trauma. T h e patient was a full-term infant, and his develop m e n t a l m i l e s t o n e s w e r e n o r m a l for h i s a g e . Examination showed an alert a n d smiling infant. T h e right eye h a d blepharoptosis, but t h e p u p i l w a s n o t c o v e r e d . H e w a s u n a b l e to adduct, elevate, or depress the eye. T h e pupil w a s 2 m m a n d r e a c t i v e . T h e left e y e s h o w e d mild blepharoptosis, a n d again, the pupil was n o t o c c l u d e d . A d d u c t i o n o f t h e left e y e w a s 5 0 % o f n o r m a l , and h e was u n a b l e to elevate or d e p r e s s t h e left e y e . T h e p u p i l w a s 5 m m d i l a t e d and weakly reactive to light. Neither eye showed signs o f aberrant regeneration o f the oculomotor nerve. O t h e r cranial nerves were intact. A magnetic resonance imaging scan demon s t r a t e d an a b s e n t c a u d a t e a n d l e n t i f o r m n u c l e us o n t h e r i g h t ( F i g . 1 ) . T h e a b s e n c e o f c y s t s o r h i g h s i g n a l i n t e n s i t y in t h e r e g i o n o f t h e b a s a l ganglia on the T^-weighted i m a g e indicated early d a m a g e to or aplasia or hypoplasia o f the structures, as o p p o s e d to s e c o n d a r y destruction d u r i n g l a t e g e s t a t i o n o r at b i r t h . T h e r i g h t frontal h o r n was dilated secondary to caudate nucleus aplasia (Fig. 2 ) . T h e internal capsule appeared normal bilaterally. Coronal views of the orbits showed hypoplas ia o f e x t r a o c u l a r m u s c l e s i n n e r v a t e d b y t h e oculomotor nerve (Fig. 3 ) . T h e right muscles a p p e a r e d to b e m o r e a f f e c t e d t h a n t h e left, c o n s i s t e n t w i t h t h e p h y s i c a l e x a m i n a t i o n , in which the right blepharoptosis a n d ocular
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Fig. 1 (Good and associates). Tj-weiglited image shows normal caudate, lentiform, and thalamus structures on the left. On the right, the caudate and lentiform nuclei are gone (arrows). The absence of bright signal in the region of the basal ganglia indi cates that this is not a destructive process. m o v e m e n t s w e r e w o r s e t h a n t h e left. T h e l a t e r al r e c t i a n d s u p e r i o r o b l i q u e m u s c l e s a p p e a r e d normal.
Discussion An i n f r a - a x i a l ( b r a i n s t e m ) a n o m a l y w a s t h e m o s t l i k e l y c a u s e of this c h i l d ' s b i l a t e r a l o c u l o motor nerve palsy. The perinatal history was u n r e m a r k a b l e , w h i c h s u g g e s t e d that t r a u m a p r o b a b l y was n o t a factor in t h e o c u l o m o t o r nerve palsy. There was no aberrant regenera tion of t h e o c u l o m o t o r n e r v e ( s y n k i n e s i s ) , a finding that u s u a l l y o c c u r s w i t h p e r i p h e r a l o c u l o m o t o r n e r v e lesions.^ T h e m a g n e t i c r e s o n a n c e i m a g i n g s c a n s h o w e d an a b s e n c e o f b a s a l g a n g l i a s t r u c t u r e s o n t h e side w i t h t h e m o s t severe involvement. The Tj-weighted image s h o w e d n o b r i g h t s i g n a l in t h i s r e g i o n , w h i c h e x c l u d e d an injury after t h e 2 0 t h g e s t a t i o n a l week. D e m o n s t r a t i o n o f a c e n t r a l c a u s e for o c u l o m o t o r n e r v e p a l s y in c o n g e n i t a l c a s e s is diffi cult. M o s t c h i l d r e n w i t h c o n g e n i t a l o c u l o m o t o r nerve palsy survive into adulthood, which has r e s u l t e d in a s c a r c i t y o f p a t h o l o g i c m a t e r i a l . N e v e r t h e l e s s , W i b r a n d a n d Saenger** r e p o r t e d o n e c a s e o f h y p o p l a s i a of a p o r t i o n o f t h e oculomotor nucleus. Other cranial nerves were
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Fig. 2 (Good and associates). Tj-weighted image shows a dilated right frontal horn caused by absence of the caudate nucleus (small arrow). The high signal intensity (large arrows) of the posterior limb of the internal capsule is normal bilaterally.
a l s o affected. N o r m a n ' d e s c r i b e d an i n f a n t w i t h a unilateral o c u l o m o t o r nerve palsy caused by a nonocclusive thrombus of the basilar artery. A p a t i e n t d e s c r i b e d b y P a p s t a n d Esslen* h a d hypoplasia of oculomotor nerve nuclei and bi l a t e r a l facial n e r v e p a l s y . M i l l e r ' d e s c r i b e d a p a t i e n t in w h o m h y p o p l a s i a o f o c u l o m o t o r nerve nuclei was a c c o m p a n i e d by digital a n o m alies and mental retardation. Most cases of congenital oculomotor palsy are u n i l a t e r a l . Two c a s e s r e p o r t e d b y R e i n e c k e ' " and one by Balkan and H o y t ' were bilateral. The patient of Balkan and Hoyt had a Marcus Gunn jaw wink p h e n o m e n o n , developmental delays, and a normal labor and delivery. T h e j a w w i n k i n g i m p l i e d a c o n d i t i o n that w a s c e n tral r a t h e r t h a n p e r i p h e r a l . W e a g r e e that c o n genital oculomotor nerve palsy can be caused by peripheral lesions during parturition; h o w ever, the likelihood of isolated bilateral in volvement without other obvious neurologic damage caused by birth trauma seems remote and should suggest a central mechanism. In our p a t i e n t , t h e r i g h t p u p i l w a s n o t i n v o l v e d a n d t h e left w a s p a r t i a l l y a f f e c t e d . In t h e s t u d i e s b y Victor^ a n d Miller,'' all p a t i e n t s had pupillary involvement, but s o m e t i m e s the pupil was miotic because of aberrant regen e r a t i o n . Four o f t h e p a t i e n t s o f B a l k a n a n d
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Bilateral Congenital Oculomotor Nerve Palsy in a Child
Fig. 3 (Good and associates). Coronal view of the globes and extraocular muscles. Note that muscles innervated by the oculomotor nerve are small com pared to the lateral rectus and superior oblique mus cles (arrows). On the right, the medial rectus muscle cannot be identified. Hoyt* s h o w e d n o p u p i l l a r y a b n o r m a l i t y . In a d u l t s , p u p i l s p a r i n g o c u l o m o t o r n e r v e p a l s y is usually caused by sparing of the pupillomotor fibers in m i c r o v a s c u l a r i n f a r c t s o f t h e e x t r a axial n e r v e . " ' ^ N a d e a u a n d Trobe,'^ h o w e v e r , described pupil sparing o c u l o m o t o r nerve palsy caused by midbrain infarction and brainstem glioma. Other reports described pupillary spar ing w i t h i n f a r c t i o n o f t h e b r a i n s t e m " a n d infil t r a t i o n o f t h e b r a i n s t e m b y tumor.'* It s e e m s that p u p i l l a r y s p a r i n g in c o n g e n i t a l o c u l o m o t o r n e r v e p a l s y , t h e r e f o r e , is t h e e x c e p t i o n b u t d o e s not preclude a central origin. The embryologic characteristics o f the oculo motor nucleus support the possibility of a pupil sparing, central o c u l o m o t o r nerve palsy. O c u l o m o t o r n e r v e n u c l e i form d u r i n g t h e fifth g e s tational week. T h e globus pallidus and striatum form at t h e s a m e t i m e . " A fifth-gestational week event could d a m a g e oculomotor nerve nuclei and basal ganglia structures. The Edinger-Westphal nucleus does not b e c o m e distin g u i s h a b l e u n t i l t h e t e n t h or 1 1 t h g e s t a t i o n a l w e e k . It c o u l d b e s p a r e d o r p a r t i a l l y s p a r e d in the event of earlier damage. The extraocular muscles innervated by the o c u l o m o t o r n e r v e w e r e s m a l l in b o t h e y e s o f our p a t i e n t ( F i g . 3 ) . T h e m u s c l e s o f t h e r i g h t e y e w e r e s m a l l e r t h a n t h o s e of t h e left e y e , w i t h t h e
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right medial rectus muscle virtually absent. S t a n d a r d s for n o r m a l - s i z e m u s c l e s d o n o t e x i s t , but the superior oblique and lateral recti mus cles, innervated by the trochlear and abducens cranial nerves, respectively, were much larger. Embryologically, the extraocular muscles form at five w e e k s . N u c l e i o f t h e o c u l o m o t o r n e r v e c a n b e i d e n t i f i e d in t h e m e s e n c e p h a l i c t e g m e n t u m b y t h e fifth week.''' O c u l o m o t o r n e r v e fi b e r s e m e r g e from t h e b r a i n s t e m at s i x w e e k s and reach appropriate extraocular muscles thereafter. The extremely small size of extraoc ular m u s c l e s in this scan (Fig. 3 ) , w h i c h was t a k e n at a n e a r l y a g e , i m p l i e s a p r e n a t a l d i s e a s e process and the possibility that s o m e of these muscles, particularly on the right, never re c e i v e d any i n n e r v a t i o n . H o r t o n a n d a s s o c i a t e s ' * d o c u m e n t e d a d e c r e a s e in t h e s i z e o f e x t r a o c u lar m u s c l e s in a c q u i r e d c r a n i a l n e r v e p a l s y . In our p a t i e n t , h o w e v e r , t h e m u s c l e s i n n e r v a t e d by the o c u l o m o t o r n e r v e s were extremely small, and the right medial rectus muscle was virtually absent. This case demonstrates that congenital oculo m o t o r nerve palsy can b e caused b y develop m e n t a l a n o m a l i e s o f t h e b r a i n . We a g r e e w i t h B a l k a n a n d Hoyt* t h a t o t h e r n e u r o l o g i c a b n o r malities can accompany congenital oculomotor nerve palsy. Magnetic resonance imaging scan ning in patients with c o n g e n i t a l o c u l o m o t o r n e r v e p a l s y m a y i d e n t i f y c h i l d r e n at risk for neurologic problems. Since extraocular muscles can be hypoplastic, scanning may also allow the s t r a b i s m u s s u r g e o n to f o r m u l a t e a r e a l i s t i c treatment plan.
References 1. Rucker, C. W.: Paralysis of the third, fourth, and sixth cranial nerves. Am. ] . Ophthalmol. 46:787, 1958. 2. : The causes of paralysis of third, fourth, and sixth cranial nerves. Am. ] . Ophthalmol. 61:1293, 1966. 3. Victor, D. I.: The diagnosis of congenital unilat eral third nerve palsy. Brain 9 9 : 7 1 1 1 , 1 9 7 6 . 4. Miller, N. R.: Solitary oculomotor nerve palsy in childhood. Am. J . Ophthalmol. 8 3 : 1 0 6 , 1977. 5. Balkan, R., and Hoyt, C. S.: Associated neuro logic abnormalities in congenital third nerve palsies. Am. J. Ophthalmol. 9 7 : 3 1 5 , 1 9 8 4 . 6. Wilbrand, H. O., and Saenger, Α.: Die kongeni talen augenmuskellahmungen (kernaplasie) in der. Neurol. Auges 8:179, 1 9 2 4 . 7. Norman, M. G.: Unilateral encephalomalacia in
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cranial nerve nuclei in neonates. Report of two cases. Neurology 24:424, 1974. 8. Papst, W., and Esslen, E.: Elektromyographischer beitrag zum Möbius syndrom. Klin. Mo natsbl. Augenheilkd. 137:401, 1 9 6 0 . 9. Miller, N. R.: Walsh and Hoyt's Clinical Neuroophthalmology, ed. 4, vol. 2. Baltimore, Williams and Wilkins, 1985, p. 6 5 3 . 10. Reinecke, R. D.: Surgical results of third crani al nerve palsies. N.Y. State J. Med. 72:1255, 1972. 11. Dreyfus, P. M, Hakim, S., and Adams, R. D.: Diabetic ophthalmoplegia. Arch. Neurol. Psychiatry 77:337, 1957. 12. Asbury, A. K., Audredge, H., and Hershberg, R.: Oculomotor palsy in diabetics. A clinicopathological study. Brain 93:555, 1970. 13. Nadeau, S. E., and Trobe, J. D.: Pupil-sparing in oculomotor palsy. A brief review. Ann. Neurol. 13:143, 1983.
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14. Starr, N. Α.: Ophthalmoplegia externa par tialis. J. Nerv. Ment. Dis. 13:300, 1 8 8 8 . 15. Gonyea, Ε. F., and Collins, J. Η.: Neuro-ophthalmic pathological correlates in primary reticulum cell sarcoma of the nervous system. J. Neurol. Neurosurg. Psychiatry 37:1005, 1974. 16. Wilkins, D. E., and Samhour, A. M.: Isolated bilateral oculomotor paresis due to lymphoma. Neu rology 28:1425, 1979. 17. Sidman, R. L., and Rokic, P.: Development of the human central nervous system. In Haymaker, W., and Adams, R. D. (eds.): Histology and Histopathology of the Nervous System. Springfield, Charles C Thomas, 1982, pp. 3 - 1 4 5 . 18. Horton, J. C , Tsai, R.-K., Truwit, C. L., and Hoyt, W. F: Magnetic resonance imaging of superior oblique muscle atrophy in acquired trochlear nerve palsy. Am. J. Ophthalmol. 110:315, 1 9 9 0 .
OPHTHALMIC MINIATURE
Mostly these days when I go to the b e a c h I just stay out o f the water altogether. I sit on the shore and play cretin, sand-digging games with my three-year-old son, and I watch the lifeguards, w h o sit way up on the b e a c h with their 2 0 - 2 0 vision and blow their whistles at swimmers I couldn't see even with the aid of a radio telescope, off the coast of France s o m e w h e r e . Dave Barry, Dave Barry's Greatest Hits New York, Fawcett C o l u m b i n e , 1 9 8 8 , p. 25
W i l l i a m V. Good, M.D., A. James Barkovich, M . D . , Bonnie L. Nickel, M . D . , and Creig S. Hoyt, M . D .
We t r e a t e d a 3 - m o n t h - o l d b o y w i t h b i l a t e r a l congenital oculomotor nerve palsy in w h o m a magnetic resonance imaging scan demonstrat ed a d e v e l o p m e n t a l b r a i n a n o m a l y i n t h e r e gion of the basal ganglia. T h e pupil was nor mal on one side, and there was n o aberrant r e g e n e r a t i o n of t h e o c u l o m o t o r n e r v e . W e c o u l d find n o e v i d e n c e for a p e r i p h e r a l o c u l o motor nerve lesion. T h i s demonstrates that congenital oculomotor nerve palsy can be caused by brainstem disease. Embryologically, b a s a l g a n g l i a a n d o c u l o m o t o r n u c l e i d e v e l op at the same time, and t h e Edinger-Westphal nucleus develops later. Thus, pupil sparing does not exclude a central origin for congeni tal o c u l o m o t o r n e r v e p a l s y .
ISOLATED OCULOMOTOR NERVE PALSY in c h i l d r e n is u n c o m m o n c o m p a r e d to adults''^ a n d o f t e n c o n g e n i t a l in n a t u r e . T h e l o c a t i o n o f t h e l e s i o n causing the congenital oculomotor palsy has b e e n p r e s u m e d to b e in t h e p e r i p h e r a l n e r v e o n the basis of two clinical observations: aberrant regeneration of the oculomotor nerve occurs c o m m o n l y in c o n g e n i t a l a n d t r a u m a t i c cases*; and associated neurologic problems in children with oculomotor nerve palsy are uncommon,^ although this observation has been chal lenged.* We t r e a t e d a c h i l d w i t h c o n g e n i t a l , b i l a t e r a l o c u l o m o t o r p a l s y in w h o m a m a g n e t i c r e s o nance imaging scan showed aplasia of basal ganglia structures on one side. T h e small size of extraocular muscles innervated b y this nerve a l s o s u g g e s t s that o c u l o m o t o r n e r v e n u c l e u s Accepted for publication Jan. 2, 1991. From the Departments of Ophthalmology (Drs. Good and Hoyt) and Radiology (Dr. Barkovich), University of California, San Francisco, California. Dr. Nickel is in private practice in San Rafael, California. Reprint requests to William V. Good, M.D., 400 Par nassus Ave., A 704, San Francisco, CA 94143.
hypoplasia or aplasia was the cause o f this child's oculomotor palsy.
Case Report A 3 - m o n t h - o l d b o y w a s e x a m i n e d in c o n s u l t a t i o n at t h e U n i v e r s i t y o f C a l i f o r n i a , S a n F r a n c i s c o , for e x o t r o p i a a n d b i l a t e r a l b l e p h a r o p t o sis. T h e r e was n o history o f birth trauma. T h e patient was a full-term infant, and his develop m e n t a l m i l e s t o n e s w e r e n o r m a l for h i s a g e . Examination showed an alert a n d smiling infant. T h e right eye h a d blepharoptosis, but t h e p u p i l w a s n o t c o v e r e d . H e w a s u n a b l e to adduct, elevate, or depress the eye. T h e pupil w a s 2 m m a n d r e a c t i v e . T h e left e y e s h o w e d mild blepharoptosis, a n d again, the pupil was n o t o c c l u d e d . A d d u c t i o n o f t h e left e y e w a s 5 0 % o f n o r m a l , and h e was u n a b l e to elevate or d e p r e s s t h e left e y e . T h e p u p i l w a s 5 m m d i l a t e d and weakly reactive to light. Neither eye showed signs o f aberrant regeneration o f the oculomotor nerve. O t h e r cranial nerves were intact. A magnetic resonance imaging scan demon s t r a t e d an a b s e n t c a u d a t e a n d l e n t i f o r m n u c l e us o n t h e r i g h t ( F i g . 1 ) . T h e a b s e n c e o f c y s t s o r h i g h s i g n a l i n t e n s i t y in t h e r e g i o n o f t h e b a s a l ganglia on the T^-weighted i m a g e indicated early d a m a g e to or aplasia or hypoplasia o f the structures, as o p p o s e d to s e c o n d a r y destruction d u r i n g l a t e g e s t a t i o n o r at b i r t h . T h e r i g h t frontal h o r n was dilated secondary to caudate nucleus aplasia (Fig. 2 ) . T h e internal capsule appeared normal bilaterally. Coronal views of the orbits showed hypoplas ia o f e x t r a o c u l a r m u s c l e s i n n e r v a t e d b y t h e oculomotor nerve (Fig. 3 ) . T h e right muscles a p p e a r e d to b e m o r e a f f e c t e d t h a n t h e left, c o n s i s t e n t w i t h t h e p h y s i c a l e x a m i n a t i o n , in which the right blepharoptosis a n d ocular
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Fig. 1 (Good and associates). Tj-weiglited image shows normal caudate, lentiform, and thalamus structures on the left. On the right, the caudate and lentiform nuclei are gone (arrows). The absence of bright signal in the region of the basal ganglia indi cates that this is not a destructive process. m o v e m e n t s w e r e w o r s e t h a n t h e left. T h e l a t e r al r e c t i a n d s u p e r i o r o b l i q u e m u s c l e s a p p e a r e d normal.
Discussion An i n f r a - a x i a l ( b r a i n s t e m ) a n o m a l y w a s t h e m o s t l i k e l y c a u s e of this c h i l d ' s b i l a t e r a l o c u l o motor nerve palsy. The perinatal history was u n r e m a r k a b l e , w h i c h s u g g e s t e d that t r a u m a p r o b a b l y was n o t a factor in t h e o c u l o m o t o r nerve palsy. There was no aberrant regenera tion of t h e o c u l o m o t o r n e r v e ( s y n k i n e s i s ) , a finding that u s u a l l y o c c u r s w i t h p e r i p h e r a l o c u l o m o t o r n e r v e lesions.^ T h e m a g n e t i c r e s o n a n c e i m a g i n g s c a n s h o w e d an a b s e n c e o f b a s a l g a n g l i a s t r u c t u r e s o n t h e side w i t h t h e m o s t severe involvement. The Tj-weighted image s h o w e d n o b r i g h t s i g n a l in t h i s r e g i o n , w h i c h e x c l u d e d an injury after t h e 2 0 t h g e s t a t i o n a l week. D e m o n s t r a t i o n o f a c e n t r a l c a u s e for o c u l o m o t o r n e r v e p a l s y in c o n g e n i t a l c a s e s is diffi cult. M o s t c h i l d r e n w i t h c o n g e n i t a l o c u l o m o t o r nerve palsy survive into adulthood, which has r e s u l t e d in a s c a r c i t y o f p a t h o l o g i c m a t e r i a l . N e v e r t h e l e s s , W i b r a n d a n d Saenger** r e p o r t e d o n e c a s e o f h y p o p l a s i a of a p o r t i o n o f t h e oculomotor nucleus. Other cranial nerves were
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Fig. 2 (Good and associates). Tj-weighted image shows a dilated right frontal horn caused by absence of the caudate nucleus (small arrow). The high signal intensity (large arrows) of the posterior limb of the internal capsule is normal bilaterally.
a l s o affected. N o r m a n ' d e s c r i b e d an i n f a n t w i t h a unilateral o c u l o m o t o r nerve palsy caused by a nonocclusive thrombus of the basilar artery. A p a t i e n t d e s c r i b e d b y P a p s t a n d Esslen* h a d hypoplasia of oculomotor nerve nuclei and bi l a t e r a l facial n e r v e p a l s y . M i l l e r ' d e s c r i b e d a p a t i e n t in w h o m h y p o p l a s i a o f o c u l o m o t o r nerve nuclei was a c c o m p a n i e d by digital a n o m alies and mental retardation. Most cases of congenital oculomotor palsy are u n i l a t e r a l . Two c a s e s r e p o r t e d b y R e i n e c k e ' " and one by Balkan and H o y t ' were bilateral. The patient of Balkan and Hoyt had a Marcus Gunn jaw wink p h e n o m e n o n , developmental delays, and a normal labor and delivery. T h e j a w w i n k i n g i m p l i e d a c o n d i t i o n that w a s c e n tral r a t h e r t h a n p e r i p h e r a l . W e a g r e e that c o n genital oculomotor nerve palsy can be caused by peripheral lesions during parturition; h o w ever, the likelihood of isolated bilateral in volvement without other obvious neurologic damage caused by birth trauma seems remote and should suggest a central mechanism. In our p a t i e n t , t h e r i g h t p u p i l w a s n o t i n v o l v e d a n d t h e left w a s p a r t i a l l y a f f e c t e d . In t h e s t u d i e s b y Victor^ a n d Miller,'' all p a t i e n t s had pupillary involvement, but s o m e t i m e s the pupil was miotic because of aberrant regen e r a t i o n . Four o f t h e p a t i e n t s o f B a l k a n a n d
Vol. I l l , No. 5
Bilateral Congenital Oculomotor Nerve Palsy in a Child
Fig. 3 (Good and associates). Coronal view of the globes and extraocular muscles. Note that muscles innervated by the oculomotor nerve are small com pared to the lateral rectus and superior oblique mus cles (arrows). On the right, the medial rectus muscle cannot be identified. Hoyt* s h o w e d n o p u p i l l a r y a b n o r m a l i t y . In a d u l t s , p u p i l s p a r i n g o c u l o m o t o r n e r v e p a l s y is usually caused by sparing of the pupillomotor fibers in m i c r o v a s c u l a r i n f a r c t s o f t h e e x t r a axial n e r v e . " ' ^ N a d e a u a n d Trobe,'^ h o w e v e r , described pupil sparing o c u l o m o t o r nerve palsy caused by midbrain infarction and brainstem glioma. Other reports described pupillary spar ing w i t h i n f a r c t i o n o f t h e b r a i n s t e m " a n d infil t r a t i o n o f t h e b r a i n s t e m b y tumor.'* It s e e m s that p u p i l l a r y s p a r i n g in c o n g e n i t a l o c u l o m o t o r n e r v e p a l s y , t h e r e f o r e , is t h e e x c e p t i o n b u t d o e s not preclude a central origin. The embryologic characteristics o f the oculo motor nucleus support the possibility of a pupil sparing, central o c u l o m o t o r nerve palsy. O c u l o m o t o r n e r v e n u c l e i form d u r i n g t h e fifth g e s tational week. T h e globus pallidus and striatum form at t h e s a m e t i m e . " A fifth-gestational week event could d a m a g e oculomotor nerve nuclei and basal ganglia structures. The Edinger-Westphal nucleus does not b e c o m e distin g u i s h a b l e u n t i l t h e t e n t h or 1 1 t h g e s t a t i o n a l w e e k . It c o u l d b e s p a r e d o r p a r t i a l l y s p a r e d in the event of earlier damage. The extraocular muscles innervated by the o c u l o m o t o r n e r v e w e r e s m a l l in b o t h e y e s o f our p a t i e n t ( F i g . 3 ) . T h e m u s c l e s o f t h e r i g h t e y e w e r e s m a l l e r t h a n t h o s e of t h e left e y e , w i t h t h e
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right medial rectus muscle virtually absent. S t a n d a r d s for n o r m a l - s i z e m u s c l e s d o n o t e x i s t , but the superior oblique and lateral recti mus cles, innervated by the trochlear and abducens cranial nerves, respectively, were much larger. Embryologically, the extraocular muscles form at five w e e k s . N u c l e i o f t h e o c u l o m o t o r n e r v e c a n b e i d e n t i f i e d in t h e m e s e n c e p h a l i c t e g m e n t u m b y t h e fifth week.''' O c u l o m o t o r n e r v e fi b e r s e m e r g e from t h e b r a i n s t e m at s i x w e e k s and reach appropriate extraocular muscles thereafter. The extremely small size of extraoc ular m u s c l e s in this scan (Fig. 3 ) , w h i c h was t a k e n at a n e a r l y a g e , i m p l i e s a p r e n a t a l d i s e a s e process and the possibility that s o m e of these muscles, particularly on the right, never re c e i v e d any i n n e r v a t i o n . H o r t o n a n d a s s o c i a t e s ' * d o c u m e n t e d a d e c r e a s e in t h e s i z e o f e x t r a o c u lar m u s c l e s in a c q u i r e d c r a n i a l n e r v e p a l s y . In our p a t i e n t , h o w e v e r , t h e m u s c l e s i n n e r v a t e d by the o c u l o m o t o r n e r v e s were extremely small, and the right medial rectus muscle was virtually absent. This case demonstrates that congenital oculo m o t o r nerve palsy can b e caused b y develop m e n t a l a n o m a l i e s o f t h e b r a i n . We a g r e e w i t h B a l k a n a n d Hoyt* t h a t o t h e r n e u r o l o g i c a b n o r malities can accompany congenital oculomotor nerve palsy. Magnetic resonance imaging scan ning in patients with c o n g e n i t a l o c u l o m o t o r n e r v e p a l s y m a y i d e n t i f y c h i l d r e n at risk for neurologic problems. Since extraocular muscles can be hypoplastic, scanning may also allow the s t r a b i s m u s s u r g e o n to f o r m u l a t e a r e a l i s t i c treatment plan.
References 1. Rucker, C. W.: Paralysis of the third, fourth, and sixth cranial nerves. Am. ] . Ophthalmol. 46:787, 1958. 2. : The causes of paralysis of third, fourth, and sixth cranial nerves. Am. ] . Ophthalmol. 61:1293, 1966. 3. Victor, D. I.: The diagnosis of congenital unilat eral third nerve palsy. Brain 9 9 : 7 1 1 1 , 1 9 7 6 . 4. Miller, N. R.: Solitary oculomotor nerve palsy in childhood. Am. J . Ophthalmol. 8 3 : 1 0 6 , 1977. 5. Balkan, R., and Hoyt, C. S.: Associated neuro logic abnormalities in congenital third nerve palsies. Am. J. Ophthalmol. 9 7 : 3 1 5 , 1 9 8 4 . 6. Wilbrand, H. O., and Saenger, Α.: Die kongeni talen augenmuskellahmungen (kernaplasie) in der. Neurol. Auges 8:179, 1 9 2 4 . 7. Norman, M. G.: Unilateral encephalomalacia in
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cranial nerve nuclei in neonates. Report of two cases. Neurology 24:424, 1974. 8. Papst, W., and Esslen, E.: Elektromyographischer beitrag zum Möbius syndrom. Klin. Mo natsbl. Augenheilkd. 137:401, 1 9 6 0 . 9. Miller, N. R.: Walsh and Hoyt's Clinical Neuroophthalmology, ed. 4, vol. 2. Baltimore, Williams and Wilkins, 1985, p. 6 5 3 . 10. Reinecke, R. D.: Surgical results of third crani al nerve palsies. N.Y. State J. Med. 72:1255, 1972. 11. Dreyfus, P. M, Hakim, S., and Adams, R. D.: Diabetic ophthalmoplegia. Arch. Neurol. Psychiatry 77:337, 1957. 12. Asbury, A. K., Audredge, H., and Hershberg, R.: Oculomotor palsy in diabetics. A clinicopathological study. Brain 93:555, 1970. 13. Nadeau, S. E., and Trobe, J. D.: Pupil-sparing in oculomotor palsy. A brief review. Ann. Neurol. 13:143, 1983.
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14. Starr, N. Α.: Ophthalmoplegia externa par tialis. J. Nerv. Ment. Dis. 13:300, 1 8 8 8 . 15. Gonyea, Ε. F., and Collins, J. Η.: Neuro-ophthalmic pathological correlates in primary reticulum cell sarcoma of the nervous system. J. Neurol. Neurosurg. Psychiatry 37:1005, 1974. 16. Wilkins, D. E., and Samhour, A. M.: Isolated bilateral oculomotor paresis due to lymphoma. Neu rology 28:1425, 1979. 17. Sidman, R. L., and Rokic, P.: Development of the human central nervous system. In Haymaker, W., and Adams, R. D. (eds.): Histology and Histopathology of the Nervous System. Springfield, Charles C Thomas, 1982, pp. 3 - 1 4 5 . 18. Horton, J. C , Tsai, R.-K., Truwit, C. L., and Hoyt, W. F: Magnetic resonance imaging of superior oblique muscle atrophy in acquired trochlear nerve palsy. Am. J. Ophthalmol. 110:315, 1 9 9 0 .
OPHTHALMIC MINIATURE
Mostly these days when I go to the b e a c h I just stay out o f the water altogether. I sit on the shore and play cretin, sand-digging games with my three-year-old son, and I watch the lifeguards, w h o sit way up on the b e a c h with their 2 0 - 2 0 vision and blow their whistles at swimmers I couldn't see even with the aid of a radio telescope, off the coast of France s o m e w h e r e . Dave Barry, Dave Barry's Greatest Hits New York, Fawcett C o l u m b i n e , 1 9 8 8 , p. 25
