Bilateral aberrant regeneration of the third cranial nerve following trauma Case report JAMES R. KEANF~ M . D .

Department of Neurology, LA C~ USC Medical Center, Los Angeles, California

This 6-year-old boy, after recovery from prolonged coma following head trauma, exhibited the rare phenomenon of bilateral oculomotor nerve misdirection manifested by ipsilateral eyelid elevation on adduction of either eye. KEvWORDS 9 thirdnerve aberrant regeneration 9 bilateral third nerve injury

M

ISDIRECTION o f regenerating oculo-

motor nerve fibers is a well-known phenomenon, particularly likely to occur after third cranial nerve damage by carotid aneurysms or trauma. The peculiar eye movements characteristic of aberrant regeneration of the third nerve were described by Gowers in 1879;s the currently accepted explanation of misdirection of regenerating peripheral nerve fibers was suggested by Bielschowsky in 1935,2 and experimentally reproduced by Bender and Fulton x in 1938. It has become increasingly apparent that minor degrees of misdirection are common; however, the bilateral aberrant regeneration ~r are reporting is rare and the associated synkinetic eye movements may be diagnoscically perplexing. Case Report

A previously healthy 6-year-old boy was kicked in the left side of his forehead by a horse and was promptly admitted to a local hospital. J. Neurosurg. / Volume 43 / July, 1975

9 headtrauma

Examination. The patient was comatose, with fixed dilated pupils and decerebrate posturing in response to painful stimuli. A nearly circumferential, horizontal skull fracture was present on x-ray films. Cerebral swelling was diagnosed but an emergency bifrontal decompression craniectomy revealed no confirmatory evidence of swelling. Course. The patient's condition had changed little 2 weeks later. Painful stimuli evoked decerebrate posturing, pupils were fixed at 8 mm, and there was no eye movement spontaneously or on oculocephalic maneuvers. Caloric testing was not performed. One month after the accident he began to grimace and show purposeful withdrawal from painful stimuli; by 2 months he was able to open his eyes halfway, to say a few words, and walk a few steps with assistance. Four months after the accident, he was oriented, emotionally labile, and walking with an unsteady gait. He had bilateral ptosis, which was greater on the right, fixed 7-mm pupils, and marked exotropia. Although he exhibited good lateral eye movements, up95

J. R. K e e n e each 7 mm in diameter, fixed to light, and did not constrict with eye movement. The horizontal range of eye movements was full, elevation was mildly limited bilaterally, and downward gaze could not be elicited. No globe movement occurred on forced lid closure. Gaze to either side was accompanied by lid elevation on the side of the adducting eye and lid droop on the abducting side (Fig. 1). Upward gaze produced moderate upwardbeating nystagmus with marked synchronous left upper eyelid jerks. Attempted downward gaze produced unsustained left eyelid nystagmus. A moderate upward nystagmus response accompanied by left lid nystagmus could be elicited on optokinetic stimulation, but no downward beats were evoked; horizontal optokinetic nystagmus was normal aside from minimal right medial rectus slowing. Neither convergence nor miosis occurred on near fixation with either eye. Discussion Misdirection has been observed following third cranial nerve injury from aneurysms, trauma (including surgical trauma), syphilis and othei meningovascular inflammation, congenital causes, and cavernous sinus thrombosis).8 lo By far the most common association is with carotid aneurysm, with ward and medial movements were more various studies disclosing an 84%,5 38%,7 and limited in the right than in the left eye. Two 50%4 incidence of aberrant regeneration years after the accident, extraocular muscle following third nerve palsy due to aneurysm. surgery on the right eye to decrease the exo- Bilateral misdirection is rare. One case tropia and right hypertropia resulted in following a subacute traumatic subdural hematoma with probable secondary tentorial modest cosmetic improvement. Follow-up Studies. When seen in herniation has been described briefly.6 ophthalmoneurological consultation 21/2years Knowledge of another case following trauma after trauma, the patient was well coor- is mentioned by Walsh and Hoyt. 1~ The specific pattern of regeneration is undinated and able to participate in sports. There was an impressive decrease in mental predictable in a given instance, but certain function characterized by hyperactivity, a phenomena are frequently observed; these inshort attention span, poor memory, and clude synkinetic lid elevation and pupillary slowness in school work. The ophthalmo- constriction when innervation of other third logical findings were significant. The visual nerve muscles is attempted, vertical eye acuity was 20/20 in the right eye and 20/30 in movement limitation (upward usually greater the left, and color vision was normal in each than downward), absent vertical optokinetic eye when tested with Hardy-Rand-Rittler response, and medial eye deviation on plates. Visual fields were full and the fun- attempted vertical eye movement. In the present case, ipsilateral lid elevation duscopic examination was normal except for mild bilateral optic disc pallor. Exotropia, on adduction of either eye indicated that right hypertropia, and a slight right head tilt some fibers normally innervating the medial were present, and on preferred fixation with recti had regenerated aberrantly to supply the the left eye, the right palpebral fissure was levator muscles. Vertical nystagmus indicated smaller than the left (Fig. 1). The pupils were residual brain stem dysfunction, but the synFI~. 1. Photographs of patient with oculomotor dysfunction. Upper: Forward gaze. Middle."On gaze to the right, the left palpebral fissure widens and the right narrows. Lower: On gaze to the left, the palpebral fissure changes reverse.

96

J. Neurosurg. / Volume 43 / July, 1975

Third

cranial nerve

regeneration

chronous left eyelid nystagmus probably represented misdirection of superior rectus fibers to the levator muscle. The inability to depress the globes, in the presence of nearly normal elevation, would be unusual in misdirection, and m a y represent a central palsy of downward gaze. Differentiation between direct third nerve damage and o c u l o m o t o r dysfunction from secondary tentorial herniation is a c o m m o n and frequently difficult task in the patient with head trauma. Diagnostic confusion with the resulting unnecessary surgical measures in the present case might have been obviated by the observation of immediate pupillary and globe paralysis; h o w e v e r , the rarity of bilateral traumatic o c u l o m o t o r nerve injury in patients with reasonable survival potential made this a difficult diagnosis.

References 1. Bender MB, Fulton JF: Functional recovery in ocular muscles of a chimpanzee after section of the oculomotor nerve. J Neurophysiol 1:144-151, 1938 2. Bielschowsky A: Lectures on motor anomalies of the eyes. 2. Paralysis of individual eye

aT. Neurosurg. / Volume 43 / J u l y , 1975

muscles. Arch Ophthalmol 13:33-59, 1935 3. Gowers WR: The movements of the eyelids. Med-Chir Trans, London 62:429-440, 1879 4. Grayson MC, Soni SR, Spooner VA: Analysis of the recovery of third nerve function after direct surgical intervention for posterior communicating aneurysms. Br J Ophthalmol 58:118-125, 1974 5. Hepler RS, Cantu RC: Aneurysms and third nerve palsies: ocular status of survivors. Arch Ophthalmol 77:604-608, 1967 6. Norton E, Wetzig P: Aberrant regeneration of third cranial nerve. Arch Ophthaimol 51:400-401, 1954 7. Raja IA: Aneurysm-induced third nerve palsy. J Neurosurg 36:548-551, 1972 8. Sturm R J, Smith JL: Aberrant regeneration of the oculomotor nerve: monocular optokinetic response. Trans Am Acad Ophthaimoi Otolaryngol 69:1054-1060, 1965 9. Walsh FB: Third nerve regeneration: a clinical evaluation. Brit J Ophthalmol 41:577-598, 1957 10. Walsh FB, Hoyt WF: Clinical NeuroOphthalmology, ed 3. Baltimore, Williams and Wilkins Co, 1969, pp 256-261 Address reprint requests to: James R. Keane, M.D., Box 359, 1200 North State Street, Los Angeles, California 90033.

97

Bilateral aberrant regeneration of the third cranial nerve following trauma. Case report.

This 6-year-old boy, after recovery from prolonged coma following head trauma, exhibited the rare phenomenon of bilateral oculomotor nerve misdirectio...
469KB Sizes 0 Downloads 0 Views