A case of left third nerve palsy and contralateral vertical gaze palsy with medial midbrain infarction]

An 81-year-old man developed oculomotor nerve palsy of the left eye and vertical gaze palsy of the right eye due to left medial midbrain infarction. His left eyelid was ptotic and the pupil was dilated. His right eye showed normal horizontal movement and Bell's phenomenon was preserved although the oculocephalic reflex was incomplete. There were no other abnormal neurological findings. The brain MRI revealed a high-intensity lesion in left medial midbrain on T2 weighted image. This lesion involved the oculomotor nerve nucleus, the interstitial nucleus of Cajal, and the rostral intersititial nucleus of the medial longitudinal fasciculus (riMLF). We thought that upward gaze palsy of the right eye was resulted from the infarction of the left riMLF or disruption of the axonal collateral of upward gaze fibers in the left oculomotor nucleus. Downward gaze palsy was resulted from the damage of the downward gaze fibers before their decussation, or the damage of the left interstitial nucleus of Cajal. This case provides evidence that unilateral lesion of the midbrain could cause contralateral vertical gaze palsy.     

Midbrain infarction presenting isolated inferior rectus nuclear palsy]

We presented a patient of isolated inferior rectus muscle palsy from midbrain lacunar infarction involving the oculomotor nucleus. The patient noticed sudden onset diplopia gazing to the right side, especially to the right-lower direction. He did not have any other symptom, and neurological examination revealed no other findings. Brain MRI documented the focal hyperintense lesion on T2-weighted images in the right-median midbrain ventral to the aqueduct at the level of the superior colliculus. This lesion involved the right oculomotor nucleus, especially the dorso-lateral subnucleus extend to the inferior rectus muscle. The oculomotor nuclear complex consists of one unpaired subnucleus and four paired subnuclei. Among them, the inferior rectus subnucleus lies dorso-laterally. So nucleus lesion may cause isolated weakness of one of muscles innervated by the oculomotor nerve. Among them the isolated inferior rectus muscle palsy can occur relatively.     

Isolated nuclear oculomotor nerve palsy due to mesencephalic infarction

A patient with unilateral nuclear oculomotor palsy due to midbrain infarction is described. A 46-year-old man was admitted because of difficulty in opening right eye and double vision noticed when he awoke in that morning. On admission, neurological examination revealed total right oculomotor palsy with slight impairment of left upward gaze. There were no other neurologic abnormalities at all. Brain CT and cerebral angiograms were also normal. Magnetic resonance imaging (MRI) performed on the ninth day, however, demonstrated high signal intensity in the right tegmentum of the mesencephalon on T2-weighted images, which was shown more clearly after the administration of Gadolinium-DPTA. He was diagnosed as nuclear third nerve palsy caused by midbrain infarction. The majority of isolated oculomotor nerve palsy has been reported to be caused by extraaxial lesion. When the oculomotor palsy is caused by intraaxial ischemic lesion, it is usually accompanied by other brain stem signs, because abundant nuclei and fibers are present adjacent to the oculomotor nucleus and nerve in the mesencephalon. The present case clarified that such a small infarct disclosed only by MRI can cause isolated oculomotor nerve palsy. It is emphasized that the intraaxial ischemic lesion should be ruled out by using the sophisticated diagnostic aid before making diagnosis of peripheral lesion. This is the first report of the isolated third nerve palsy resulting from mesencephalic ischemic lesion in the Japanese.     

The clinical and MRI correlate of ischaemia in the ventromedial midbrain: Claude's syndrome

The eponymous syndrome of Claude is caused by a lesion of the red nucleus and adjacent third nerve nucleus, resulting in the combination of an ipsilateral oculomotor palsy and contralateral ataxia. The MRI correlate of this syndrome has only occasionally been described. We present three cases with MRI findings which confirm the association of this clinical syndrome with infarction of the ventromedial midbrain. The coexistence of hypertension and small vessel ischaemia in two cases suggests this type of infarct may arise as a result of small vessel disease. Received: 26 September 2000, Received in revised form: 11 April 2001, Accepted: 23 April 2001     

A patient with reversible pupil-sparing Weber's syndrome

This is a case report of a lady who presented with pupil-sparing Weber's syndrome. She had left oculomotor nerve palsy with normal pupil and right hemiparesis. The patient subsequently made a good recovery. An ischemic lesion of the lower mid-brain was demonstrated on the MRI scan of the brain, which corresponds to the motor nucleus of the oculomotor nerve. The article also describes the neuroanatomy of the oculomotor nerve and how its partial lesions lead to sparing of the pupil. In addition, this case report documents that a pupil-sparing Weber's syndrome could be reversible.     

Isolated crossed superior rectus palsy in a midbrain infarction]

A 61-year-old man suddenly heard tinnitus and diplopia at night during watchinng television. A few days later he visited at our hospital. Neurologically he exibited marked isolated right superior rectus palsy which was also indicated by the Hess test. No other neurological abnormalities were found such as other ocular muscle paresis, cranial nerve palsies, hemiparesis, sensory impairement or cerebellar ataxia. MRI showed a left medial thalamic infarction extending to a rostral part of the midbrain anterolateral to the cerebral aqueduct at the superior colliculi level. Unilateral superior rectus palsy can rarely be caused by a contralateral midbrain infarction, because fibers from the subnucleus subserving the superior rectus decussate within the oculomoter nerve complex. In this case the crossing fibers toward the contralateral superior rectus may have been selectively involved by a tinny lesion in the area of the oculomotor nucleus. The patient had a slightly narrowed right palpebral fissure. It is indicated that crossing fibers toward the contralateral levator muscle of the eyelid may be also involved. The patient's diplopia completely resolved two months later after the onset.     

Claude's syndrome associated with supranuclear horizontal gaze palsy caused by dorsomedial midbrain infarction

Claude's syndrome caused by dorsal midbrain lesion is characterized by ipsilateral third nerve palsy and contralateral ataxia. To date, reports in the literature concerning Claude's syndrome associated with the midbrain paresis of horizontal gaze are rare. A 62-year-old man suddenly developed left third cranial nerve palsy, right lateral gaze palsy, and right ataxia. Intact Bell's phenomenon and preserved right horizontal oculocephalic reflex suggested the lateral gaze palsy in the right eye was supranuclear in nature. Magnetic resonance imaging (MRI) revealed an infarction in the left dorsomedial midbrain. Although the red nucleus has often been suggested as the lesion site responsible for Claude's syndrome, a lesion of the superior cerebellar peduncle just below and medial to the red nucleus could be responsible for this syndrome. This case demonstrates neurological heterogeneity of midbrain infarction.     

A case of partial fascicular oculomotor paresis caused by midbrain infarction]

We report a 74-year-old man with an ischemic lesion in the ventral midbrain. He presented with contralateral ptosis and marked upward gaze paresis of the right eye. Neurological examination revealed partial oculomotor nerve palsy caused by impairment of the right levator palpebrae, superior rectus and inferior oblique muscles. This finding is highly suggestive of a possible lesion in the midbrain affecting the oculomotor fascicular fibers. Magnetic resonance images showed an ischemic lesion in the paramedian area of the right midbrain tegmentum. The coronal view of T 2-weighted imaging clearly demonstrated to be the site of lesions below the red nucleus. It seemed to be coincidental with the impaired site of involving the caudal part of oculomotor fascicular fibers emerging from the nucleus. This report is considered to be a typical case of partial fascicular oculomotor paresis based on impairment of the caudal part of oculomotor fascicles for the levator palpebrae, superior rectus, and inferior oblique muscles. This is a valuable case to be documented in which neurological site of lesions are consistent with those found in radiological study.     

Pupil sparing in oculomotor palsy: A brief review

The clinical dictum that pupil sparing in oculomotor nerve palsy predicts an extraaxial ischemic lesion while pupil involvement predicts an extraaxial compressive lesion has some important exceptions. Two case reports and a review of the literature disclose that pupil sparing occurs in a small proportion of intraaxial and compressve subarachnoid oculomotor nerve lesions and in a large proportion of compressive cavernous sinus oculomotor nerve lesions. Careful examination is also necessary to separate examples of apparent pupil sparing in cases of aberrant regeneration and in some instances of cavernous sinus compression.     

Fascicular arrangement within the oculomotor nerve MRI analysis of a midbrain infarct.

The fascicular arrangement of the oculomotor nerve within the midbrain is not adequately elucidated in humans. We treated a patient with a partial oculomotor palsy who had impaired adduction and supraduction on the left side, which were attributed to an ipsilateral lacunar infarct. CT and MRI revealed a discrete lesion in the centre of the midbrain tegmentum in the rostrocaudal plane. This case suggests that the oculomotor fibres for extraocular movement are located in the middle of the the midbrain, and supports the fascicular proximity of the superior and medial rectus muscles. The fascicular arrangement of the midbrain oculomotor nerve is speculated to be pupillary component, extraocular movement and eyelid elevation in that rostrocaudal order, based on the previous reports of neuro-ophthalmological impairment and MRI findings, which are analogous to the nuclear arrangement proposed by Warwick.     

Crossed innervation of the superior rectus.

We studied two patients which showed a paralysis of the oculomotor nerve on one side and isolated paralysis of the superior rectus on the other side. On the side of oculomotor nerve paralysis, midbrain infarct extending from the paramedian tegmentum to crus cerebri was demonstrated in one case who showed no recovery, and a small lacuna in midbrain tegmentum in another one who showed complete recovery. On the side of isolated paralysis of the superior rectus, no lesion was demonstrated by CT and MRI, and no clinical signs of the involvement of fiber tracts or nuclei were evident in both cases. A unilateral lesion of oculomotor nerve nucleus caused a paralysis of the contralateral superior rectus.     

Bilateral ptosis with pupil sparing because of a discrete midbrain lesion: magnetic resonance imaging evidence of topographic arrangement within the oculomotor nerve.

The topographic arrangement within the midbrain oculomotor nerve is not adequately elucidated in humans. Two patients with a partial oculomotor palsy because of a localized infarction or hematoma were treated. Both patients had bilateral ptosis, impaired adduction, and supraduction. One patient had impaired infraduction and pupillary involvement on one side. Results of computed tomography and magnetic resonance imaging revealed discrete lesions at the dorsal midbrain tegmentum that spared the rostral midbrain. The authors' cases elucidate that pupillary components take the most rostral course. This report provides indirect magnetic resonance imaging evidence to prove the course of pupillary fibers. Based on the different neuro-ophthalmologic findings in the authors' cases (sparing or affecting pupillary component and infraduction), the nerves of the inferior rectus and inferior oblique for infraduction pass more rostrally than those of medial rectus, superior rectus, and levator palpebrae. The nuclear and fascicular arrangement within the midbrain oculomotor nerve is speculated to be pupillary, extraocular, and eyelid elevation in the rostro-caudal order, based on the neuro-ophthalmologic impairment and magnetic resonance imaging findings in the authors' patients and in previous animal experiments. Knowing the fascicular and nuclear arrangement within the midbrain in detail will offer diagnostic clues for differentiation of causes for partial oculomotor palsy.     

Isolated superior rectus palsy due to contralateral midbrain infarction

BACKGROUND: Isolated superior rectus palsy due to a contralateral midbrain lesion has not been reported. CASE DESCRIPTION: A 71-year-old woman suddenly developed diplopia. Examination showed that she had isolated superior rectus paresis. Magnetic resonance imaging showed a tiny infarct at the area of the oculomotor nucleus on the contralateral side. CONCLUSION: Isolated superior rectus palsy may be caused by a contralateral midbrain lesion that selectively involves crossing superior rectus nerve fibers.     

Traumatic oculomotor nerve palsy.

Traumatic isolated oculomotor nerve palsy is not common. Oculomotor nerve palsy without internal ophthalmoplegia (pupil sparing) is extremely rare. We report a case of this condition in a child. An 11-year-old boy was transferred to our hospital after a head injury in a traffic accident. Neuro-ophthalmic examination showed that the left eye had limited adduction, supraduction, and infraduction, incomplete convergence and left ptosis, but no internal ophthalmoplegia. Magnetic resonance imaging indicated mild bending of the ipsilateral oculomotor nerve at the posterior petroclinoid ligament. One month after injury, movement of the patient's eyes was normal on examination, but there was mild diplopia. The suggested mechanism of the oculomotor nerve palsy with pupil sparing in this case is stretching of the oculomotor nerve at the posterior petroclinoid ligament, maintaining an intact pupillomotor nerve.     

Study of the rostral midbrain atrophy in progressive supranuclear palsy

Rostral midbrain atrophy in progressive supranuclear palsy (PSP) is detected by mid-sagittal plain magnetic resonance imaging (MRI). The shape of the atrophy looks like the bill of a hummingbird (hummingbird sign). We studied this sign to elucidate the nature of midbrain atrophy in PSP. Eight patients with PSP, 12 with Parkinson's disease (PD), and 10 normal controls were studied. Using mid-sagittal plain MRI, we measured the rostral and caudal midbrain tegmentum (MT), superior and inferior colliculus, pontine base, and tegmentum. We compared the length of the interpeduncular fossa, which is posterior to the mammillary body, to the diameter of the midbrain tegmentum. The multiple comparison method was used for the statistical analysis. The hummingbird sign was demonstrated in all of the PSP patients studied, and it was not observed in PD patients nor in normal controls. The hummingbird sign in the PSP patients was due to the atrophy of the midbrain tegmentum (rostral and caudal) and to a relative increase in the length of the interpeduncular fossa over that of the anteroposterior diameter of the midbrain tegmentum. The hummingbird sign, which represents the atrophy of the rostral midbrain tegmentum, strongly suggests the involvement of the rostral interstitial nucleus of the medial longitudinal fasciculus in patients with PSP. Demonstration of a hummingbird sign on MRI is thought to be useful for a diagnosis of PSP.     

Divergence paralysis due to a lesion of the lateral tegmentum of the midbrain caused by thalamic hemorrhage]

A 66-year-old diabetic and hypertensive man suddenly developed right hemiplegia. Examination revealed right hemiplegia including his face, vertical gaze palsy, and divergence paralysis. The cranial CT scan disclosed a left thalamic hemorrhage as large as 40 mm in diameter, which extended to the midbrain. He was treated medically and his divergence paralysis improved. But all other symptoms remained for the next 11 months and he eventually died of acute retroperitoneal hemorrhage. The autopsy revealed spongy state and gliosis extending from the left thalamic nuclei to the left midbrain. In the tegmentum, dorsolateral part around the left oculomotor nucleus was involved. The precise location of the human divergence center of the eyes is still unknown. According to previous reports, the divergence center may locate in the tegmentum of the midbrain or pons. Recently, animal experiments detected the neurons which fire for divergent in the mesencephalic reticular formation just dorsal and lateral to the oculomotor nuclei. Our case had a lesion of gliosis and spongy state, namely the old hematoma, in the same portion. Therefore, we considered that the human divergence center of the eyes might exist in the lateral tegmentum of the midbrain, just lateral and dorsal to the oculomotor nucleus.     

Supranuclear paralysis of monocular elevation.

A man with bronchogenic carcinoma lost the ability to elevate his left eye voluntarily. His eyes were level in the primary position and the Bell phenomenon was normal, indicating that the ophthalmoplegia was caused by a supranuclear lesion. Other clinical and radiologic evedence indicated that there was a lesion in the rostral midbrain. A metastatic tumor, found in the right pretectum at autopsy, probably produced the ophthalmoplegia by interrupting axons destined for the superior rectus portion of the homolateral oculomotor nucleus and the interior oblique portion of the contralateral oculomotor nucleus.     

Magnetic resonance imaging in a case of paramedian mesencephalic infarction

A case of paramedian midbrain infarction was studied by magnetic resonance imaging. The clinical syndrome included a paralysis of the oculomotor nerve sparing the pupil and cerebellar disorders of the opposite side. MRI disclosed a cylindrical infarction in the paramedian midbrain tegmentum.     

Lymphoma as a cause of isolated oculomotor nerve palsy

We report two patients with diffuse large B-cell lymphoma with isolated oculomotor nerve palsy. This was the initial manifestation of lymphoma in one patient but in a second, the palsy appeared as a part of a generalized recurrence of lymphoma. In addition, we reviewed the clinical findings of 12 previously reported patients. Isolated oculomotor nerve palsy was most frequently associated with the large B-cell lymphoma cell type, and was not frequently associated with periorbital pain. The pupil was spared in half the patients irrespective of infiltration of the oculomotor nerve. MRI and cerebrospinal fluid cytological examinations are helpful in determining invasion of lymphoma to the oculomotor nerve, cavernous sinus, and surrounding leptomeninges.     

Unilateral midbrain infarction causing upward and downward gaze palsy.

We report on a 47-year-old-woman who developed sudden complete loss of vertical saccades, smooth pursuit, and vestibular eye movements bilaterally. MRI revealed a unilateral midbrain infarct involving the rostral interstitial nucleus of the medial longitudinal fasciculus (riMLF) and the interstitial nucleus of Cajal (INC) and spared the posterior commissure (PC). The lesion is presumed to have interrupted the pathways involved in vertical gaze just before they decussate, inducing an anatomically unilateral but functionally bilateral lesion. Previous reports of bidirectional vertical gaze palsy have shown lesions involving the PC or both riMLFs. This case is the first to show that a unilateral lesion of the riMLF and the INC that spares the PC may cause complete bidirectional vertical gaze palsy.