SANS Neuroopthalmology Flashcards
Seorang pria 25 tahun dengan onset baru wajah bagian kanan tertarik ke bawah dan diikuti binocular horizontal diplopia. MRI pada bagian otak menunjukkan adanya hiperintensitas batang otak pada T2 dan gambaran FLAIR (lihat gambar). Secara anatomis, bagian manakah yang mengakibatkan lesi tersebut menyebabkan diplopia?
A. Medial longitudinal fasciculus
B. Abduscens fibers
C. Abduscens nucleus
D. Trochlear nucleus
E. Trapezoid body
C. Abduscens nucleus
The patient’s symptoms are due to pathology at the level of the abducens nucleus. The presence of the facial weakness accompanying the diplopia with a fourth ventricular mass suggests the anatomical substrate of this lesion as the level of the facial colliculus, where facial fibers loop around the abducens nucleus.
Pathology affecting the abducens fibers independently would not be associated with facial weakness. While the medial longitudinal fasciculus (MLF) mediates conjugate gaze, transmitting lateral gaze signals from the abducens nucleus to the contralateral oculomotor nucleus, it is not the structure primarily involved in this patient. A patient with an isolated MLF lesion would have bilaterally preserved abduction without conjugate adduction of the contralateral eye but preserved convergence. The trochlear nucleus is at the level of the midbrain and disease at this level would not result in horizontal diplopia but rotatory diplopia compensated with head tilt away from the affected side. The trapezoid body is part of the auditory pathway and not involved in eye movements.
Such a lesion is expected to be associated with peripheral seventh nerve palsy and a nuclear sixth nerve palsy causing ipsilateral facial and conjugate gaze palsy. A lesion of the sixth nerve nucleus, by damaging neurons innervating the ipsilateral lateral rectus muscle and the interneurons for the contralateral medial rectus, will cause ipsilateral conjugate gaze palsy. Because of the anatomic proximity of the genu of the facial nerve to the sixth nerve nucleus, nuclear sixth nerve palsy is often accompanied by ipsilateral facial nerve weakness as seen in this classic case of facial colliculus syndrome. Occasionally, the infranuclear nerve of the abducens nucleus will be affected instead of the nucleus itself, causing isolated abducens palsy. Common causes of facial colliculus syndrome include: demyelination, tumor, cavernous malformation, hemorrhage, and ischemia.
Seorang wanita hamil berusia 27 tahun dengan hilangnya penglihatan secara progresif tanpa nyeri pada mata kanan. Pada pemeriksaan didapatkan hasil negatif pada persepsi cahaya dan respon pupil secara langsung pada mata kanannya, nervus optikus kanan yang pucat dan penurunan lapang pandang temporal-superfisial pada mata kiri. Etiologi dari tanda dan gejala pasien tersebut dikarenakan oleh :
A. Pituitary apoplexy
B. Optic neuritis
C. PRES (posterior reversible encephalopathy syndrome)
D. Meningioma Suprasellar
E. Hilangnya penglihatan fungsional
D. Meningioma Suprasellar
This constellation of findings is most consistent with a suprasellar lesion. Meningiomas, pituitary adenomas, and glial tumors are known to enlarge during pregnancy. Progestrone receptor positive meningiomas as well as prolactinomas are known to enlarge during pregnancy causing chiasmal compression. Pituitary tumors will typically present with bitemporal blur or vision loss confirmed on formal visual field testing. Visual acuities and color vision may be mildly affected, and pupil testing is typically normal.
Posterior reversible encephalopathy syndrome (PRES) can present during pregnancy, typically after the 20th week, associated with pregnancy induced hypertension (pre-eclampsia, or eclampsia). Symptoms include headache, seizures, confusion and vision loss. Patients with PRES describe subacute painless vision loss ranging from blurring to no light perception. Their exam will demonstrate normal pupillary testing. The fundus/optic disc may be normal or demonstrate hypertensive edema and vascular changes. MRI reveals cortical and subcortical hyperintensity on fluid attenuation inversion recovery (FLAIR) MRI typically in the posterior lobes suggestive of vasogenic edema. Visual impairment typically resolves completely weeks to months later. Pathogenesis is thought to occur at the vascular endothelium impairing autoregulation and increasing cerebral perfusion pressure resulting in vasogenic edema. Predisposing factors include acute hypertension, pre-eclampsia, immunosuppressive agents (especially cyclosporine), sepsis, and connective tissue diseases.
Pituitary apoplexy is an acute hemorrhage and/or infarction of a pre-existing pituitary adenoma. Almost all patients present with headache. Vomiting, diplopia and vision loss are common symptoms as well. Physiologic hyperplasia of the pituitary gland during pregnancy occurs, and has been reported to cause visual symptoms. Lymphocytic hypophysitis is an autoimmune lymphocytic infiltration of the anterior pituitary lobe, typically diagnosed in the third trimester or postpartum, which may also cause chiasmal compression.
Optic neuritis typically presents with unilateral painful central vision loss over hours to days. Exam reveals mild to severe vision loss, decreased color vision, ipsilateral relative afferent papillary defect (RAPD), and visual field defect only in one eye.
This patient has a junctional scotoma on visual field testing ie: complete ipsilateral loss and contralateral superior temporal defect. Junctional scotomas localize to the proximal optic nerve. Contralateral inferonasal retinal ganglion cells crossing in the chiasm loop slightly forward into the proximal optic nerve before proceeding to the optic tract (referred to as the anterior knees of Willebrand). Any type of compressive lesion in this location can cause this defect.
While functional vision loss (FVL) is more prevelant in the female population, there is no known association with pregnancy. Patients with FVL have no objective findings.
While functional vision loss (FVL) is more prevelant in the female population, there is no known association with pregnancy. Patients with FVL have no objective findings.
Seorang wanita 58 tahun dengan riwayat diabetes terkontrol dan hipertensi, tanpa riwayat trauma, datang dengan oculomotor synkinesis diantara otot extraocular yang menyebabkan adduksi atau retraksi global pada usaha pasien menatap secara vertikal. Apakah yang paling mungkin sebagai penyebab dari temuan klinis pasien tersebut?
A. Infark otak tengah (Midbrain infarct)
B. Lesi besar pada parasellar
C. Diabetic third nerve palsy
D. Thyroid associated orbitopathy
E. Tumor regio pineal
B. Lesi besar pada parasellar
A patient without history of a preceding 3rd nerve palsy and evidence of oculomotor nerve synkinesis suggests a slow growing mass lesion within the cavernous sinus, typically a meningioma or aneurysm. Parasellar meningiomas and aneurysmal compression of the subarachnoid portion of the 3rd nerve can also cause primary oculomotor synkinesis. This patient demonstrates a pseudo von-Graefe sign, i.e. upper lid retraction on down gaze (may occur with adduction as well) due to aberrant regeneration. Additional aberrant regenerative finding include miosis with adduction or depression, co-contraction of the vertical rectus muscles with globe retraction. Vertical gaze restriction may present before the pseudo von-Graefe sign, and both might be missed without extraocular motility examination in all 9 cardinal directions of gaze.
Peripheral motor and sensory nerves are able to regenerate to some degree after an injury. Aberrant regeneration results in “misdirected” distal nerve segments to an extra-ocular muscle other than originally innervated. Oculomotor synkinesis after blunt or surgical trauma to the nerve (secondary oculomotor nerve synkinesis) typically occurs about 9 weeks after the injury. Patients describe sudden onset diplopia at the time of the trauma. It is extremely rare to develop aberrant regeneration after a diabetic or ischemic third nerve palsy. Ischemic nerve injuries will begin to improve within 4-6 weeks, and most resolve by 3 months. A left midbrain infarct can cause an isolated nuclear 3rd nerve palsy, however, the patient may have normal ispilateral superior rectus and levator function due to contralateral innervation. An oculomotor nuclear infarct would not likely develop synkinesis. A fascicular 3rd nerve injury will cause an ipsilateral complete 3rd nerve palsy, however, is typically associated with contralateral hemiparesis ie Weber’s syndrome. Hyperthyroidism and/or Grave’s eye disease (thyroid associated orbitopathy) can cause restrictive eye movements, proptosis, lid retraction and lagophthalmos (von-Graefe sign). It is unusual to have unilateral signs. Periorbital pain or ache is common and the pupil would not be involved.
Seorang pria 65 tahun dengan diplopia horizontalis progresif yang buruk saat melirik ke kanan. hasil pemeriksaan menunjukkan ada defisit abduksi parsial pada mata kanan, ptosis ringan pada mata kanan atas, dan anisokoria dimana pupil sebelah kanan lebih kecil dari kiri. Hasil pemeriksaan lain dalam batas normal. Dimana lokasi lesi yang paling mungkin?
A. Dorello’s canal
B. Sinus kavernosus
C. Apex orbital
D. Arteri communicans posterior
B. Sinus kavernosus
The correct answer is the cavernous sinus.
This patient has a right sixth nerve paresis and right Horner syndrome (ptosis, miosis, dilation lag). Horner syndrome is caused by disruption of the oculosympathetic pathway. The sympathetic outflow to the iris dilator muscle is a paired, three-neuron chain without decussation. The first-order neuron (central) originates in the hypothalamus and descends through the brainstem into the lateral column of the spinal cord, where it synapses at the cervicothoracic junction (level C8-T2). The second-order neuron (preganglionic) leaves the spinal cord and travels over the apex of the lung to synapse at the superior cervical ganglion at the level of the carotid artery bifurcation. The third-order neuron (postganglionic) follows a course along the internal carotid artery, passes through the cavernous sinus where the post-ganglionic fibers are briefly associated with the abducens (VI) nerve and then the ophthalmic nerve (V1). The fibers then travel with the long ciliary nerve through the superior orbital fissure, and end within the iris dilator muscle and the retractor muscles of the upper and lower eyelids.
The combination of a Horner syndrome and VI nerve palsy is highly suggestive of a cavernous sinus lesion. A pontine lesion could also cause a VI nerve palsy and Horner syndrome.
As mentioned above, the oculosympathetic chain travels through the superior orbital fissure, not the orbital apex. Unlike the sixth nerve, it does not travel within Dorello’s canal.
A posterior communicating artery aneurysm can present as a third nerve palsy with pupillary involvement. The affected pupil is larger with decreased reactivity to the light. Upgaze, downgaze, and adduction can be partially or completely affected.
Seorang pria berusia 77 tahun dengan riwayat hipertensi yang tidak terkontrol, terbangun dengan hilangnya penglihatan bilateral. Hasil pemeriksaan menunjukkan tidak ada reaksi pada persepsi cahaya di kedua mata, respon pupil yang normal tanpa adanya defek afferen relatif, tak ada kelumpuhan pada pandangan dan diskus optikus normal. pasien tampak sedikit kebingungan berbicara dengan lancar. akan tetapi, selama pemeriksaan, pasien mengalami aphasia global dengan deviasi pandangan ke kiri serta kekakuan tonik pada tangan kirinya selama 45 detik.
A. Sindroma ensefalopati posterior yang reversibel
B. Top of the basila syndrome
C. Retinopati hipertesif
D. Sindrom Balint
E. Amaurosis fugax
A. Sindrom ensefalopati posterior yang reversibel
The correct answer is Posterior reversible encephalopathy syndrome (PRES).
PRES typically presents with sub acute painless bilateral vision loss ranging from blurring to no light perception, headache, altered mental status, aphasia, and/or seizures. Exam demonstrates normal pupillary testing and fundus/optic disc findings. MRI reveals subcortical white matter changes in the posterior lobes on T2 sequences (see figure). DWI sequences typically do not demonstrate restriction suggestive of infarct. Visual impairment typically resolves within 2-3 weeks.
Pathophysiology is due to increased vascular permeability of the posterior circulation, which supplies not only the primary and association visual cortices but also the medial temporal lobes. Therefore, patients also can be confused and have seizures. Infection has been associated with PRES. Additional associations include Cyclosporine/FK-506 toxicity, eclampsia, autoimmune, increasing or acute hypertension with or without associated chronic renal disease. PRES has been reported secondary to hypertensive therapy for subarachnoid hemorrhage induced vasospasm.
Patients with PRES and who are anticoagulated are at greater risk for hemorrhagic transformation independent of blood pressure.
Top of the basilar syndrome typically presents with occipital lobe, midbrain and/or pontine, medial temporal lobe, and thalamic lesions. Lesions are usually ischemic due to occlusion, which involves both the subcortical and cortical tissue. Midbrain and/or pontine lesions will cause ophthalmoparesis, contralateral hemiparesis, or quadraplegia i.e. “locked in syndrome”. Occlusion can be from artery to artery embolus from an atheromatous plaque or vertebral dissection, or cardiac source usually atrial fibrillation. Spontaneous vertebral dissection has been associated with concomitant infection.
Amaurosis fugax usually refers to a transient ischemic attack during which vision is lost often due to an embolus unilaterally obstructing the lumen of the retinal artery or ophthalmic artery. Pupillary reactivity would be impaired and it would be an isolated event and not associated with seizures.
Most patients with hypertensive retinopathy present without visual symptoms however some may report decreased vision or headaches. The retinal exam would not be normal.
Balint syndrome is the triad of simultanagnosia, optic ataxia, and ocular apraxia. This syndrome is typically seen in bi-parietal lesions or neurodegenerative disorders such as Alzheimer’s disease and Posterior cortical atrophy. MRI may show posterior parieto-occipital atrophy without signal changes or enhancement, however, is typically within normal limits.
Timbulnya “macula sparing” pada defisit bidang visual hemianopic terlokalisasi pada jalur optik bagian :
A. Ciasma
B. Korteks
C. Radiations
D. Saraf
E. Traktus
B. Korteks
The correct answer is visual cortex, where macular sparing may be seen with hemianopsic defects. Optic nerve lesions typically are associated with central scotomata or altitudinal defect that respect the horizontal meridian in the visual field. Chiasmal visual field defect will show either a bitemporal hemianopia, a temporal hemianopia in one eye with a central scotoma in the other, or a superotemporal defect in one eye with a central scotoma in the other which is the classic junctional scotoma of anterior chiasmal disease. Disease of the optic tract will be associated with a hemianopia, but also a relative afferent pupillary defect; it is not associated with macular sparing. Disease of the optic radiation is also not associated with macular sparing.
In the occipital lobe, elements that serve central vision are located more posteriorly at the occipital pole. Elements that serve far peripheral vision are located more anteriorly. A lesion in the center of the calcarine cortex, a posterior cerebral artery stroke for example, will destroy most of the calcarine cortex leaving the occipital pole preserved and a small island of vision will remain in the hemianopic visual field. This island of vision is termed macular sparing and is indicative of occipital lobe disease only.
