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Show © 1990 Raven Press. Ltd., New York Congenital Double Elevator Palsy in Identical Twins John A. Bell, M. D., F. R. C. S., F. C. Ophth., Alistair R. Fielder, F. R. C. S., F. C. Ophth., and Susan Viney, D. B. a. A left- sided double elevator palsy in identical twins born prematurely is presented, the first such report in twins. The aetiology of this condition is considered, and given the preservation of Bell's phenomenon and the absence of hypotropia in the primary position, the possibility that this may represent a supranuclear defect is discussed. Key Words: Congenital double elevator palsyTwins prematurity. From the University of Leicester Medical School a · A. B., A. R. F.), Leicester, and Nottingham City Hospital ( S. V.). Nottingham, England. Address correspondence and reprint requests to Professor A. R. Fielder. f: lirminghJm and Midland Eye Hospital, Church 1,' 1' 1, , r" I" · ', · , r,:', f: n~~ J.: lnJ 32 Double elevator palsy, characterised by the limitation of elevation of one eye, is due to weakness of the muscles of elevation and may be congenital or acquired. This diagnosis is made following the exclusion of conditions such as dysthyroid eye disease, cellulitis, orbital blow- out fracture, third nerve palsy, poststrabismus surgery, trauma resulting in disinsertion of an extra ocular muscle, and various conditions associated with rigid muscles, fascia, or adjacent tissues. CASE REPORT Identical male white twins B. M. and A. M. were born at 32 weeks gestation and weighed at birth 1,415 g and 1,620 g, respectively. B. M. was a forceps delivery and required resuscitation and ventilation. A. M. was a breech delivery and required oxygen for 2 h. Both were jaundiced and received phototherapy for 3 days, and calcium supplements were given for hypocalcaemia. They were discharged from hospital on the 28th day of life. Eye examinations began 3 weeks after birth. Both developed stage I acute retinopathy of prematurity, which subsequently resolved. At 18 months of age, limited elevation of the left eye of each child was observed. There was no deviation in the primary position and, in particular, no hypotropia. Other ocular movements were full, and Bell's phenomenon was preserved. A diagnosis of double elevator palsy was made. Neither had an anomalous head position. The eyelids were normal. Pupillary reactions were normal. CycloplegiC refraction at this time was: B. M.- right, - 0.50 DS with + 1.5 DC at 90 left, - 0.50 OS with + 1.0 DC at 90; A. M.- right, + 0.50 OS, left, 0.00 with 0.50 DC at 90. No retinal abnormality was observed. CONGENITAL DOUBLE ELEVATOR PALSY 33 c A B D A B D FIG. 1. The upper sequence of twin A. M. and the lower shows twin B. M. ( A) On upgaze, there is a limitation of elevation of the left eye. ( B) Both eyes are straight in the primary position. ( C) Defective elevation in adduction of the left eye. ( 0) Defective elevation in abduction of the left eye. DISCUSSION Double elevator palsy is an uncommon disorder of ocular motility, and this is the first report of its occurrence in twins. It is interesting to note that the twins were identical and that elevation of the left eye was limited in each. Typically, in this condition, the superior rectus and the inferior oblique muscles are variably affected ( 1), resulting in limitation of elevation above the horizontal plane in all positions of gaze. In addition, in some cases, there may be ptosis due to weakness of the levator muscle or pseudoptosis consequent upon hypotropia ( 2). It would appear from the literature that although congenital defects of vertical gaze are uncommon, the most frequent is double elevator palsy. A classification has recently been suggested on the basis of eye movements, whether one or both eyes is affected, anomalous head posture, and binocularity ( 3), although it had been classified as long ago as 1943 into 3 groups according to binocularity and fixation by the nonparetic or paretic eye ( 4). The clinical identification of double elevator palsy is important, as its management is different from other mechanisms of upgaze restriction, such as blow- out fracture, dysthyroid eye disease, and Brown's syndrome. Clearly, only the last could be considered here. Treatment is generally not indicated, but in the presence of either a vertical deviation in the primary position or an anomalous head posture, the Knapp procedure has been performed ( 5). As mentioned, double elevator palsy may be acquired and lampel and Fells ( 6) in a series of eight patients, suggested that this could be due to a discrete lesion in the pretectum of the midbrain as a consequence of an occlusion of part of the microvasculature supplying that region of the brain. Lessel ( 7) reported a patient who developed a double elevator palsy in his left eye and was found at autopsy to have a metastatic tumour in the right side of the pretectum. In Rosner's opinion ( 1), the disorder was best explained by a nuclear lesion involving the rostral area of the third nucleus. Double elevator palsy can be congenital, and this is almost certainly so in our cases. These twins were enrolled in a survey of retinopathy of prema- J Clin Neuro- ophthalmol, Vol. 10, No. 1, 1990 34 J. A. BELL ET AL. turity and had been examined on over eight occasions before the ocular motility problem was identified. Nevertheless, as emphasis had been directed toward the retinal problem in previous examinations, we consider it likely that the condition had existed from birth. The aetiology of congenital double elevator palsy is obscure, especially if one accepts that within the oculomotor nucleus ( a) the fibres to the superior rectus are crossed, ( b) those to the inferior oblique are not, and ( c) that both muscles are innervated by separate branches of the oculomotor nerve ( 8). The clinical picture of the disorder can be simulated by a long- standing superior rectus palsy, as this muscle can elevate the eye without the aid of the inferior oblique. It has been reported in at least one instance of double elevator palsy that the electromyogram of the inferior oblique has been normal ( 9). In addition, structural anomalies of the extraocular muscles have been shown to be responsible. McNeer and Jampolsky ( 10) described an anomalous insertion of an extra band of the inferior rectus muscle, which produced the clinical picture of a double elevator palsy. This was confirmed by a forced duction test and surgical exploration. The presence of Bell's phenomenon in our twins thus would appear to rule out not only a mechanical aetiology, but also nuclear and infranuclear causes. It is interesting to note that neonatal hypoxia has been implicated in the aetiology of double elevator palsy, with four of five patients in one recently reported series having some form of hypoxia ( 5). This appears to be an unlikely explanation in this J CLin Neuro- op" thalnwi, u/ II), ,' iJ() case, due to the symmetry of the lesions in each twin. We have reported the finding of a left- sided double elevator palsy in identical twin boys. In the primary position, there was no ocular deviation, and Bell's phenomenon was present. We conclude that in these two children, the cause of double elevator palsy was supranuclear in origin, and the possibility of an inherited defect in this family cannot be excluded. REFERENCES 1. Rosner RS. Double elevator paralysis. Am J Ophthalmol 1963; 55: 87- 93. 2. Manley DR. Strabismus. In: Harley RD, ed. Paediatric ophthalmology. Philadelphia: Saunders 1983: 247- 8. 3. Strachan 1M, Innes JR. Congenital paralysis of vertical gaze. In: Lenk- Schafer M, ed. Orthoptic horizons. Transactions of the sixth International Orthoptic Congress. 1987: 140- 3. 4. White JW. Paralysis of the superior rectus of the inferior oblique muscle of the same eye. Arch Ophthalmol 1942; 27: 366- 8. 5. Barsoum- Homsy M. Congenital double elevator palsy. J Paediatr Ophthalmol Strabis 1983; 20: 185- 91. 6. Jampel RS, Fells P. Monocular elevation paresis caused by a central nervous system lesion. Arch Ophthalmol 1968; 80: 45- 7. 7. Lessel S. Supranuclear paralysis of monocular elevation. Neurology 1975; 25: 1134-- 6. 8. Warwick R. Representation of the extra- ocular muscles in the oculomotor nuclei of the monkey. J Comp Neurol 1953; 98: 449- 504. 9. Jampolsky A. Personal communication. In: Von Noorden GK, ed. Burian- von Noorden's binocular vision and ocular motility. St. Louis: CV Mosby Co, 1985: 362. 10. McNeer KW, Jampolsky A. Double elevator palsy caused by anomalous insertion of the inferior rectus. Am JOphthalmol 1965; 59: 317- 20. |
