Bilateral traumatic abducens nerve paralysis with cervical spine flexion injury

Bilateral traumatic abducens nerve palsy is a rare condition. We report a case associated with cervical spine flexion injury. This may be the first such case report, as no similar case was found in our review of the literature. The mechanisms of injury in this case are relevant to theories that explain hyperextension injuries.

Acute diplopia and a solitary lung mass: a unique presentation of light-chain myeloma

The patient described, a 51-year-old woman, had diplopia and cephalgia of two weeks' duration. On admission, the radiologic evaluation revealed a mass in the sphenoid sinus, multiple lesions in the calvarium and a solitary lung mass. Biopsy of the lung mass revealed an atypical plasmacytic infiltration. Laboratory findings confirmed the diagnosis of light-chain myeloma presenting with a pulmonary plasmacytoma and cranial nerve involvement.

Wildervanck syndrome

We report a case of the Wildervanck (cervico-oculo-acoustic) syndrome exhibiting Klippel-Feil anomaly, congenital sensorineural deafness and bilateral sixth nerve palsy. Associated anomalies included short stature, microcephaly, mental retardation, and cleft palate.

Acquired palsy of the oculomotor, trochlear and abducens nerves

There have been few studies primarily concerned with the relative frequencies, aetiologies and prognoses of ocular motor palsies. Those published have emanated largely from neurological tertiary referral centres rather than primary ophthalmology departments. We have performed a retrospective study of all patients with acquired III, IV or VI cranial nerve palsy who were seen in the orthoptic department at Ninewells Hospital, Dundee, over the 9 year period from 1984 to 1992. A total of 165 cases were identified. VI nerve palsies accounted for the majority of patients (57%), with IV nerve palsies (21%) occurring more frequently than III nerve palsies (17%) and multiple palsies (5%). Thirty-five per cent of cases were of unknown aetiology and 32% of vascular aetiology. The incidence of sinister pathology-neoplasia (2%) and aneurysm (1%)-was surprisingly low. Fifty-seven per cent of all patients made a total recovery (in a median time of 3 months) and 80% made at least a partial recovery. The results are contrasted with those of previous studies and the value of associated symptoms and of further investigation in the assessment of these patients is discussed.

Goldenhar, Möbius and hypoglossia-hypodactyly anomalies in a patient: syndrome or association?

The Möbius, Goldenhar and hypoglossia-hypodactyly anomalies are usually sporadic conditions with a recurrence risk of about 2%. The combination of Goldenhar and one or the two others is rare, whereas the concomitant occurrence of Möbius and hypoglossia-hypodactyly, and/or Poland, and/or Klippel-Feil anomaly is well known. Pathogenetically, vascular disruptions around the 4th embryonic week have been hypothesized. In vivo and pathological studies as well as animal models support this theory for all the above-mentioned combinations. Whether a preceding blastogenetic alteration is an influencing factor or a disorganization mutation, remains unclear. We describe a 3-year-old girl with bilateral anotia, epidermoid on the right eye, 6th and 7th nerve palsy, hypoglossia, left hypodactyly, and ventricular septal defect.

CONCLUSION

We wish to emphasize the aetiological relevance of vascular disruptions in this previously unreported combination of Möbius, Goldenhar and hypoglossia-hypodactyly anomalies. The concurrence of anomalies in this patient represents an association and not a pleiotropic syndrome.

Bilateral infarction of the rostral pontine tegmentum as a cause of isolated bilateral supranuclear sixth nerve palsy related to hypertension

Images

Cavernous sinus hemangioma. Clinical and neuroimaging features

A patient presented with an isolated left sixth nerve palsy. Magnetic resonance imaging revealed a sharply marginated 3 cm lesion in the left cavernous sinus, which was isointense to gray matter on T1-weighted images, hyperintense on T2-weighted images, and enhanced with paramagnetic contrast material. Cerebral angiography showed a homogeneous blush fed by an enlarged meningohypophyseal artery. The neuroimaging findings were thought to be most consistent with the diagnosis of a cavernous sinus meningioma. At the time of surgery, a vascular mass was encountered, and a biopsy was consistent with a cavernous hemangioma. This report describes the clinical and neuroimaging features of cavernous sinus hemangiomas that may help to differentiate them from other cavernous sinus lesions.

Simultaneous, multiple cranial neuropathies in diabetes mellitus

Cranial mononeuropathies, particularly ophthalmoplegia and facial palsy, are common entities in the diabetic population. Simultaneous multiple cranial neuropathies due to diabetes are much less common, however. We present three patients with this entity.

Recurrence of systemic lupus erythematosus in a hemodialysis patient presenting as a unilateral abducens nerve palsy

A 45-year-old hemodialysis patient presenting with recurrence of SLE which manifested predominantly as a unilateral left abducens (VIth) nerve palsy is described. The signs and symptoms of the cranial nerve palsy resolved within two weeks of initiating corticosteroid therapy. This is the first reported case of an abducens nerve palsy occurring in a maintenance hemodialysis patient associated with recurrence of SLE.

Pseudotumor cerebri (toxic effect of the "magic bullet")

A 10 year-old female patient presented to the outpatient unit of the ophthalmology department of Menelik II Hospital with complaints of inward deviation of the left eye, of three weeks' duration. The patient was on a mega dose of vitamin A 200,000 I.U. (the "magic bullet") daily for two months prior to the onset of the present illness. Physical examination revealed left sixth nerve palsy and bilateral papilloedema in an alert and oriented patient without localizing neurologic findings. The cerebrospinal fluid pressure ( > 250 mm water) was increased and skull X-ray findings were suggestive of increased intracranial pressure (IIP). This case meets the modified Dandy criteria except that a highly likely cause, hypervitaminosis A, is associated. Therefore, a diagnosis of Idiopathic Intracranial Hypertension (IIH) or Pseudotumor Cerebri was made. This disorder and its management is discussed and literature reviewed. The serious and potentially blinding toxic effect of Vitamin A, if consumed in excessive amounts, is emphasized.

Spontaneous recovery rates for unilateral sixth nerve palsies

Two hundred and thirteen patients with unilateral isolated sixth nerve palsies were assessed to determine what proportion of them underwent spontaneous recovery and over what period of time this recovery occurred. All were primary ophthalmic referrals from which trauma was excluded. In all, 78.4% of patients experienced spontaneous recovery of their palsy, 36.6% recovering by 8 weeks and 73.7% by 24 weeks. Only 16.4% failed to recover. Of this group, however, nearly 40% had serious underlying pathology accounting for their palsy.

[Horizontal gaze palsy due to lesion of the abducens nucleus detected with magnetic resonance imaging]

A case of unilateral horizontal gaze palsy is reported. The lesion of the abducens nucleus was clearly detected with magnetic resonance imaging. In the early stage, the adduction of the right eye and abduction of the left eye were completely limited and the vestibulo-ocular reflex was also impaired. However, during the recovery stage, the improvement of limitation of abduction was delayed compared with that of adduction. We suggest that this phenomenon is useful as a differential diagnosis between lesions of the abducens nucleus and of the paramedian pontine reticular formation.

Outcome of sixth nerve palsy or paresis in young children

This study evaluated the ophthalmological outcome following sixth nerve palsy or paresis in 64 children 7 years of age and younger. The outcomes considered were vision, residual strabismus and the need for strabismus surgery. Etiologies included tumor, hydrocephalus, trauma, infection, malformation, and idiopathic and miscellaneous causes. Strabismus surgery was performed on 24% of the patients, with residual strabismus present in 66% of the patients. Neurologists and ophthalmologists should monitor visual acuity in these young children at frequent intervals be prepared to institute amblyopia therapy early in the course of the ocular misalignment if permanent visual disability is to be avoided.

Optic disk swelling and abducens palsies associated with OKT3

PURPOSE/METHODS

Orthoclone OKT3 is a monoclonal murine IgG immunoglobulin used to treat acute cellular rejection of allografted organs. Aseptic meningitis and meningoencephalopathy are known adverse side effects from the drug. OKT3 caused additional ophthalmologic and neurologic complications in an 18-year-old woman who was treated for transplanted kidney graft rejection. Papilledema and bilateral abduction deficits developed.

RESULTS/CONCLUSIONS

Results of magnetic resonance imaging and magnetic resonance angiography were unremarkable. Lumbar puncture disclosed increased intracranial pressure and sterile meningeal inflammation. Most of the symptoms resolved by one week after discontinuation of OKT3. Ophthalmologists and neurologists should be aware that optic disk swelling and abducens palsies can be associated with OKT3 when used in the treatment of transplanted kidney graft rejection.

Surgical treatment of trigeminal schwannomas

A total of 27 patients with trigeminal schwannoma were treated between 1982 and 1992 at the Neurosurgery Department of Nordstadt Hospital. Twelve cases of solitary schwannoma without any family history or physical stigmata of neurofibromatosis were included and form the basis of this study. There were four women and eight men (mean age 44 years) in this series. Duration of symptoms ranged from 2 months to 6 years. The most frequent symptoms were either pain or numbness of the ipsilateral hemiface. The surgical approach was chosen depending on the tumor type. Tumors that belonged to Type A (five cases), which were predominantly in the middle fossa, were approached using a transsylvian method; Type B (one case), which presented predominantly in the cerebellopontine angle, was operated on via a retrosigmoid suboccipital craniectomy; Type C (five cases), which were dumbbell-shaped extending into both the middle and posterior fossa, were removed via a combined temporal craniotomy-presigmoidal method; and in Type D (one case), in which tumor was primarily extracranial with intracranial extension, an infratemporal extradural approach was undertaken. There was no operative mortality or long-term disability in this series. The follow-up period ranged from 12 to 60 months; during that time magnetic resonance imaging revealed tumor recurrence in two cases after 12 and 48 months, respectively, and these were excised again. An additional 178 cases collected from the world literature are also reviewed and analyzed.

Case report: sixth nerve palsy following radiculography

Complications following myelography do not usually cause serious disability. However, we report a case of sixth nerve palsy where the disability lasted a few months. We also discuss the possible pathogeneses.

[A case of abducens nerve palsy after whiplash injury]

We report a patient who developed abducens nerve palsy after whiplash injury. The patient was a 61-year-old man who was involved in a traffic accident on May 15, 1993. After the accident, he developed severe neck pain. Four days later, he still had neck pain and vertigo. On the fifth day after the accident, he noted diplopia on left gaze and visited our hospital. Neurologic examination revealed an isolated abduction deficit of the left eye. Head magnetic resonance imaging and angiography showed no abnormal findings. Ten days later, the ocular movements of the patient were full and the diplopia disappeared. About two months later, his neck pain and vertigo also resolved. In this patient, the abducens nerve palsy was caused by whiplash injury and was in full recovery.

Saccadic velocity analysis in patients with divergence paralysis

Twelve patients with clinical findings of divergence paralysis underwent horizontal saccadic velocity testing. Peak velocities were measured using digitally sampled electro-oculography during 10 degrees, 20 degrees, and 30 degrees saccades. Results were compared with those of 12 age-matched controls. The peak saccadic velocities of each eye in adduction and 10 degrees abduction did not differ from those of age-matched controls (P > .05). The 20 degrees and 30 degrees abducting saccades showed mildly reduced saccadic velocities when compared with controls (P < .05). The finding of only mildly reduced abduction saccadic velocities bilaterally is not consistent with bilateral lateral rectus palsy. The data support the hypothesis that divergence paralysis represents a distinct clinical entity unrelated to abducens nerve paresis and argues for the existence of an active divergence center. We further report the surgical results of five patients who were treated with strabismus surgery. A 4.0 to 6.0 mm bilateral lateral rectus muscle resection corrected 16 to 30 delta of esotropia at distance without resulting in an overcorrection at near. Bilateral lateral rectus muscle resection is an effective therapy for divergence paralysis.

[Preoperative prediction of the amount of surgical correction by using Botulinum A type toxin for the treatment of paralytic esotropia]

The aim of this study was to obtain the correct choice of initial surgical procedure and to predict the amount of surgical correction by using the maximum reduction rate of eye position after Botulinum A-type toxin injection for the treatment of acquired neurogenic paralytic strabismus. The subjects were 30 with sixth nerve palsy and 33 with non-paralytic esotopia with no previous surgery. The results were that if the maximum reduction rate of eye position after the first injection of 1.25 U was less than 68%, the modified Jensen procedure with recession of medial rectus muscle was necessary to achieve 100% recovery. However, if it was more than 100%, then recession-resection of the horizontal rectus muscles alone produced successful ocular alignment. Based on our data of 100 cases of sixth nerve palsy that showed spontaneous recovery, we conclude that surgical treatment should be planned, if the maximum percentage reduction of preoperative eye position after Botulinum A-type toxin treatment is under 68% (reflecting the inability of the medial rectus muscle to contract and the lengthening of the lateral rectus muscle), and if the patient has no spontaneous improvement at all within 12 weeks after onset.

Iatrogenic lateral rectus palsies. A series of five postmyelographic cases

The objective of this study was to assess the etiology of lateral rectus palsies in patients undergoing lumbar myelograms with Iopamidol (Isovue; ER Squibb and Sons, Princeton, NJ, USA; Niopam, E Merc, UK.). An audit of the departmental orthoptic record revealed two patients who had suffered abducens palsies after myelograms. A further search revealed three additional patients who had suffered similar complications. The incidence of abducens palsy in patients undergoing myelography with the contrast agent Iopamidol was found to be 1 in 500 in around 2,500 myelograms performed under standard conditions. It would appear that lateral rectus palsy in myelography is the result of the lumbar puncture, the neurotoxic effect of the contrast agent, or a combination of the two in patients with an already compromised neurophysiologic state. This is the first series to associate this problem with Iopamidol. Although usually a serious neurologic symptom, when associated with contrast myelography using Iopamidol it is important to appreciate that such symptoms usually resolve of their own accord.

Petrous apex mucocele: high resolution CT

Mucocele of the petrous apex is very rare, only three cases having been reported. Since this area is inaccessible to direct examination, imaging, preferably high resolution computed tomography (HR CT) is essential. We report a case showing an eroding, non enhancing mass with sharp, lobulated contours, within the petrous apex. The presence of a large air cell on the opposite side suggested a mucocele.

Neuro-ophthalmic findings in botulism type B

In June 1989, the largest recorded outbreak of food-borne botulism occurred in the United Kingdom. Twenty-seven patients were affected during the outbreak with type B botulism. A case note review of 14 patients admitted with this condition was performed and the neuro-ophthalmic findings are presented. Patients with severe disease presented with a combination of ocular and bulbar symptoms; in mild cases dysphagia was noted first and visual disturbance followed within 24 hours. Clustering of cases and bilaterality of cranial nerve signs aided in the diagnosis. Accommodative paresis and sixth cranial nerve palsy were frequent early signs. When there was respiratory paralysis and ventilatory failure, it occurred within 12 hours of the onset of a third cranial nerve palsy.

Abducent nerve paralysis during interferon alpha-2a therapy in a case of chronic active hepatitis C

A 59-year-old woman with chronic active hepatitis C was treated with recombinant human interferon alpha-2a. After three days of administration, the patient complained of diplopia with dizziness and head heaviness. Ophthalmic examinations revealed a disturbance of the movement of left eye ball to the outer side without any other neurological signs. The diplopia, which was diagnosed as abducent nerve paralysis, improved rapidly and reversed at about 6 weeks after discontinuation of interferon and during infusion of hydrocortisone. To our knowledge, this is the first report of abducent nerve paralysis associated with alpha-2a interferon.

Results of a prospective randomized trial of botulinum toxin therapy in acute unilateral sixth nerve palsy

Forty-seven patients entered a prospective randomized trial to assess the effect of early botulinum neurotoxin A treatment to the ipsilateral antagonist medial rectus on the ultimate recovery rate of acute unilateral sixth nerve palsy. Twenty-two patients received injections and 25 acted as controls. The overall etiologies were microvascular (72.3%), unknown (17%), multiple sclerosis (6%), and one case each of central nervous system (CNS) sarcoidosis and basilar artery ectasia. Eighty-three percent of the patients entered the trial within 2 weeks of the onset of symptoms and 95.7% within 3 weeks. The controls had a final recovery rate of 20/25 (80%), and the injected group had a final recovery rate of 19/22 (86%). No serious side effects were encountered. We conclude that there is no evidence for a prophylactic effect of botulinum toxin in the group that we have studied.

Sixth nerve palsy: an unusual manifestation of preeclampsia

BACKGROUND

Neurologic abnormalities may occur in pregnancy as a manifestation of neurologic or systemic disease. We present an unusual case of preeclampsia presenting with a sixth nerve lesion.

CASE

A 33-year-old woman, gravida 2, presented at 38 weeks' gestation with sixth nerve palsy. She was hypertensive and proteinuric, with plasma urea of 24 mg/dL. Labor was induced and hypertension escalated in the early puerperium, with concomitant worsening diplopia. Blood pressure control and resolution of preeclampsia were followed by resolution of the sixth nerve lesion. There was no evidence of other pathology on extensive investigations.

CONCLUSION

Sixth nerve palsy is an unusual manifestation of preeclampsia.

The rat abducens nucleus: a histo- and immunohistochemical study

The number and proportion of motoneurons and interneurons present in the rat abducens nucleus was determined by the use of ChAT immunostaining and of HRP staining after retrograde transport from the injected right lateral rectus muscle. After HRP injection 67% of abducens neurons took up HRP and were hence motoneurons to the muscle. The cell bodies were mainly located in the middle third of the nucleus and were either spindle-shaped or pyriform. By ChAT-immunohistochemistry, 77% of the rat abducens neurons were ChAT-positive. After considering and discarding the hypotheses that the lateral rectus muscle could be incompletely filled by HRP, and that other muscles may be innervated by abducens motoneurons, it is concluded that some interneurons of the abducens nucleus of the rat are probably cholinergic.

Isolated fascicular abducens nerve palsy and Lyme disease

A patient with Lyme disease developed an isolated sixth nerve palsy at the end of a 1 month course of oral antibiotics. Magnetic resonance imaging disclosed high-signal abnormality at the left pontomedullary junction, implicating involvement of the distal sixth nerve fascicle. Although facial numbness ensued during a subsequent course of intravenous antibiotics, corticosteroid therapy was associated with prompt improvement of neurologic signs, suggesting an immunologic mechanism for the central nervous system dysfunction.

Prenatal sonographic evidence supporting an in utero developmental etiology of Möbius sequence

Möbius sequence features masklike facies with sixth and seventh nerve palsy and frequently micrognathia thought to result from a neuromuscular deficiency in early movement of the mandible. Failure to thrive in infancy is commonly due to feeding and aspiration difficulties. We present the first description of prenatal sonographic findings associated with this lesion, which also support an in utero developmental etiology of this rare condition.

[Unilateral supranuclear abducens palsy in a pineal tumor]

A 13-year-old boy complained of frequent headaches and diplopia on rightward gaze. A CT scan demonstrated hydrocephalus and a non-homogeneous enhancing mass in the pineal area, leading to a diagnosis of pineal tumor. The physical examination revealed no abnormalities. On neurological examination, there were a right homonymous hemianopsia and slight choked disc in both optic fundi. His right eye was slightly adducted on primary gaze. On right lateral gaze, his right eye could not move beyond the midline and showed gaze paretic nystagmus, whereas his left eye could move fully in all directions. The abducens palsy could be overcome by the oculocephalic maneuver or caloric test. Interestingly, his right eye could abduct when his left eye was covered. From these finding, this was labelled a supranuclear abducens palsy. The convergent nystagmus was observed. Rightward OKN (quick phase to right) of the right eye was abolished with and without the left eye covered, while leftward OKN of the right eye was preserved. Pursuit to right was disturbed. After removal of the tumor, the gaze palsies disappeared. It is postulated that the supranuclear lateral gaze palsy was caused by impairment of supranuclear control by involvement of lateral gaze pathways to gaze center coursing near the oculomotor nucleus.

The efficacy of botulinum neurotoxin A for the treatment of complete and partially recovered chronic sixth nerve palsy

Esotropia from chronic sixth nerve palsy or paresis usually requires surgery. Chemodenervation of the antagonist medial rectus muscle, while popular for the treatment of acute sixth nerve palsies and pareses, has not been used extensively for chronic cases. In this study, 22 patients with sixth nerve palsies or partially recovered palsies of greater than 5 months duration were treated with chemodenervation. The etiologies of the sixth nerve palsies were trauma (n = 7), tumor (n = 4), infection/inflammation (n = 3), nerve compression from aneurysm or increased intracranial pressure (n = 4), congenital (n = 1), ischemia (n = 2), and idiopathic (n = 1). The mean preinjection deviation was 41 prism diopters. A total of 38 injections were administered (mean, 1.7 per patient). Each patient received an injection of 2.5 to 7.5 units (mean, 4.1) of botulinum neurotoxin A to the ipsilateral medial rectus muscle. Treatment success was assessed 6 months after the last injection. A course of chemodenervation significantly improved the alignment of 9 of the 22 patients (41%). The mean postinjection deviation was 8 delta. Seven patients (32%) had single binocular vision in primary position restored. These patients had a mean horizontal binocular field of 70 degrees (range, 40 degrees to 100 degrees). Thirteen patients (59%) had only modest improvement and required surgery. The data suggest that injection of botulinum neurotoxin A is a useful treatment for some patients with chronic sixth nerve weakness. A course of chemodenervation therapy compares less favorably with transposition surgery with concomitant neurotoxin injection for the treatment of these difficult problems.

[Persistent isolated abducens nerve palsy from pontine infarction confirmed by gadolinium-DTPA enhanced MRI]

An 80-year-old man had left isolated abducens nerve palsy after repeated conjugate deviation to the right without any other findings. MRI demonstrated no abnormal lesion of T2-weighted images, while left paramedian tegmentum pontis was enhanced as responsible lesion by gadolinium (Gd)-DTPA on the 13th hospital day when Foville syndrome lasted. On the 33rd hospital day when isolated abducens nerve palsy lasted, however, this lesion was not detected with Gd enhanced images. The diagnosis of abducens nerve palsy caused by pontine infarction was obtained. Our patient had a lesion involving the left PPRF and ipsilateral abducens nerve. We concluded that the complete damage of left abducens motoneuron may cause isolated abducens nerve palsy lasting more than one year after Foville syndrome due to the dysfunction of left PPRF. To our knowledge, this is the first report of the persistent isolated abducens nerve palsy resulting from a pontine miniature ischemic lesion speculated by Gd enhanced MRI.

One-and-a-half syndrome, type II

OBJECTIVE

To describe a second type of the one-and-a-half syndrome in which adduction rather than abduction of one eye is the preserved horizontal movement. DESIGN AND PATIENT SETTING: A patient experiencing mucormycosis of the cavernous sinus suffered a sixth-nerve palsy and simultaneous carotid artery occlusion with infarction and a contralateral horizontal gaze palsy.

RESULTS

The patient experienced an eye movement syndrome with complete paralysis of horizontal eye movement in the ipsilateral eye and paralysis of horizontal eye movement in one direction, in this case abduction due to the gaze palsy, in the contralateral eye. Adduction of the contralateral eye was the only remaining horizontal eye movement.

CONCLUSION

A lesion in the cavernous sinus producing occlusion of the internal carotid artery and a sixth-nerve palsy may produce a second type of one-and-a-half syndrome. Adduction rather than abduction of one eye is the preserved horizontal eye movement. This combination of eye movement deficits is unlikely to be produced by a lesion in any other location. Mucormycosis, with its propensity to produce vascular occlusion, is a likely, although not specific, cause.

[Neurological disease due to the varicella-zoster virus without a skin lesion]

We studied three cases of inflammatory neurological disease and serological evidence of varicella-zoster viral (VZV) infection without cutaneous manifestation. They corresponded to a case of cranial multi-neuritis, a case of aseptic meningitis, and another case of meningoencephalitis. Despite the infrequency of any such association, the spectrum of the neurological diseases associated with VZV without skin lesions is quite wide. We are motivated to present our experience by the belief that it is important to think about this possible etiology based on inflammatory areas at different levels of the Nervous System in patients who are still immunocompetent.

Remitting sixth nerve palsy in skull base tumors

OBJECTIVE

Spontaneous recovery of a sixth nerve palsy is thought to rule out a neoplastic origin. We reviewed cases of sixth nerve palsy that improved without treatment but that ultimately proved to be caused by a tumor at the base of the skull.

DESIGN

Case series.

SETTING

Hospital-based, neuro-ophthalmology referral practice.

PATIENTS

Seven patients with an age range from 7 to 61 years had sixth nerve palsy secondary to a slow-growing neoplasm at the skull base.

MAIN OUTCOME MEASURES

Return of lateral rectus function and resolution of diplopia without intervention.

RESULTS

Seven patients with sixth nerve palsy caused by skull base tumors experienced spontaneous improvement of their deficit. Recovery time ranged from 1 week to 18 months. No patient was diabetic or had evidence of vascular disease. In one patient, the palsy improved once prior to becoming a fixed deficit, and spontaneous improvement occurred on two to five occasions in the other patients.

CONCLUSION

Spontaneous recovery of a sixth nerve palsy can occur in the presence of an extramedullary compression by a tumor at the base of the brain. Possible mechanisms for recovery include remyelination, axonal regeneration, relief of transient compression (eg, resorption of hemorrhage), restoration of impaired blood flow, slippage of a nerve previously stretched over the tumor, or immune responses to the tumor.