Second lecture neuro ophthalmology
- 1. Neuro-Ophthalmology: Pupil Dr. Md. Anisur Rahman (Anjum) Professor & Head, Department of Ophthalmology Dhaka Medical College, Dhaka
- 2. Adie pupil/tonic pupil/Adie syndrome • An Adie pupil (tonic pupil, Adie syndrome) is caused by denervation of the postganglionic parasympathetic supply to the sphincter pupillae and the ciliary muscle, and may follow a viral illness. • Sites of dysfunction are presumed to be the ciliary ganglion, and, in wider Holmes–Adie syndrome, the dorsal root ganglion involved in reflex pathways. • It typically affects young women and presents in one eye in 80%, though involvement of the second eye typically develops within months or years.
- 3. Adie's tonic pupil Adie's tonic pupil refers to a dilated, poorly reactive pupil, presumably from dysfunction of the ciliary ganglion. The nerves responsible for pupil constriction connect through the ciliary ganglion. When they are damaged the pupil dilates. Sometimes, over time, the second eye becomes affected.
- 4. Adie syndrome • Adie syndrome is a neurological disorder affecting the pupil of the eye and the autonomic nervous system. It is characterized by one eye with a pupil that is larger than normal that constricts slowly in bright light (tonic pupil), along with the absence of deep tendon reflexes, usually in the Achilles tendon.
- 5. What is Adie's pupil? With Adie's pupil, there is an abnormal pupillary response to light. In most cases, it affects only one eye. The affected pupil is usually larger than normal and does not constrict as it should in the presence of bright light
- 6. Diagnosis: Symptoms. Patients may notice anisocoria, or may have blurring for near due to impaired accommodation.
- 7. Signs Pupil: Large, regular (irregularity sometimes reported). The direct light reflex is absent or sluggish. On slit lamp examination, vermiform movements of the pupillary border are typically seen. Constriction is also absent or sluggish in response to light stimulation of the fellow eye (consensual light reflex)
- 8. The pupil responds slowly to near, following which re-dilatation is also slow. Accommodation may manifest similar tonicity, with slowed and impaired focusing for near and prolonged re-focusing in the distance. In long-standing cases the pupil may become small (‘little old Adie’).
- 9. Large right pupil A) Large right pupil B) absent or sluggish direct light reflex C) consensual reflex is similar (D) diminished deep tendon reflex Right Adie pupil .
- 10. Pharmacological testing Instillation of 0.1–0.125% pilocarpine into both eyes leads to constriction of the abnormal pupil due to denervation hypersensitivity, with the normal pupil unaffected. Some diabetic patients may also show this response and very occasionally both pupils constrict in normal individuals. Syphilis serology should usually be checked in patients with bilateral tonic pupils.
- 11. Argyll Robertson pupils Argyll Robertson pupils are caused by neurosyphilis, and have been attributed to a dorsal midbrain lesion that interrupts the pupillary light reflex pathway but spares the more ventral pupillary near reflex pathway – light–near dissociation results.
- 13. Argyll Robertson pupils In dim light both pupils are small and may be irregular. In bright light neither pupil constricts, but on accommodation (near target) both constrict. The pupils do not dilate well in the dark, but cocaine induces mydriasis unless marked iris atrophy is present.
- 14. How to differentiate Argyll Robertson pupils and Adie tonic pupil? After instillation of pilocarpine 0.1% into both eyes, neither pupil constricts, distinguishing Argyll Robertson pupils from bilateral long-standing tonic pupils.
- 15. Unilateral • Afferent conduction defect • Adie pupil • Herpes zoster ophthalmicus • Aberrant regeneration of the third cranial nerve Bilateral • Neurosyphilis • Type 1 diabetes mellitus • Myotonic dystrophy • Parinaud (dorsal midbrain) syndr • Familial amyloidosis • Encephalitis • Chronic alcoholism Causes of light–near dissociation
- 16. Pituitary gland The Sella turcica (Turkish saddle) is a deep saddle-shaped depression in the superior surface of the body of the sphenoid bone in which the pituitary gland lies The roof of the Sella is formed by a fold of dura mater, the diaphragma sellae, which stretches from the anterior to the posterior clinoid process.
- 17. Upper nasal fiber Chiasma Lower nasal fiber Pituitary Gland Dorsum sellae Diaphragma sellae
- 18. • The optic nerves and chiasm lie above the diaphragma sellae; posteriorly, the chiasm is continuous with the optic tracts and forms the anterior wall of the third ventricle. A visual field defect in a patient with a pituitary tumour therefore generally indicates suprasellar extension.
- 19. • Tumours less than 10 mm in diameter (microadenomas) tend to remain confined to the Sella, whereas those larger than10 mm (macroadenomas) often extend outside.
- 20. Pituitary adenomas Tumour classification is based on the type of hormone secreted; about 25% of primary pituitary tumours do not secrete any hormones and may be asymptomatic, cause hypopituitarism and/or ophthalmic features. An older classification system divided pituitary tumours into acidophilic, basophilic and chromophobic types based on their histological staining characteristics, but is now not commonly used.
- 21. Ophthalmic features of large adenomas Large pituitary lesions may first present to ophthalmologists, often with vague visual symptoms, and a low threshold should be adopted for visual field assessment in chronic headache of any sort. It is also important to perform a careful visual field assessment on both eyes in patients with unexplained unilateral central visual impairment.
- 22. Symptoms Headache may be prominent due to local effects but does not have the usual features associated with raised ICP, and diagnostic delay is therefore common. Visual symptoms may be vague; they usually have a gradual onset and may not be noticed by the patient until well established.
- 23. Symptoms Colour desaturation across the vertical midline of the uniocular visual field is an early sign of chiasmal compression. The patient is asked to compare the colour and intensity of a red pin or pen top as it is moved from the nasal to the temporal visual field in each eye. Another technique is to simultaneously present red targets in precisely symmetrical parts of the temporal and nasal visual fields, and to ask if the colours appear the same.
- 24. Symptoms • Optic atrophy is present in approximately 50% of cases with field defects. When optic atrophy is present the prognosis for visual recovery after treatment is guarded. • When nerve fiber loss is confined to fibres originating in the nasal retina (i.e. nasal to the fovea) only the nasal and temporal aspects of the disc will be involved, resulting in a band or ‘bow tie’-shaped atrophy.
- 25. Symptoms • Papilloedema is rare. • Visual field defects depend on the location and direction of enlargement of a compressive lesion, as well as the anatomical relationship between the pituitary and chiasm. Patients may not present until central vision is affected from pressure on macular fibres.
- 26. Symptoms • Extraocular muscle paresis due to disruption of the cranial nerves traversing the cavernous sinus. • See-saw nystagmus is a rare feature.
- 27. Anatomical variations in the position of the chiasm Central 80% Prefixed 10% Post-fixed 10%
- 28. OS OD HM CF HM CF Typical progression of bitemporal visual field defects caused by compression of the chiasm from below by a pituitary adenoma. LE = left eye; RE = right eye
- 29. • Lower nasal optic nerve fibres traverse the chiasm inferiorly and anteriorly, hence the upper temporal quadrants of both visual fields are affected first by most expanding pituitary lesions, giving a bitemporal superior quadrantanopia progressing to the classic chiasmal visual field lesion, a bitemporal hemianopia (Fig) loss is commonly asymmetrical between the two eyes
- 30. Typically asymmetrical bitemporal hemianopia
- 31. Upper nasal fibres traverse the chiasm high and posteriorly and therefore are involved first by a lesion such as a craniopharyngioma that arises above the chiasm. If the lower temporal quadrants of the visual field are affected more profoundly than the upper, a pituitary adenoma
- 32. Examples of optic nerve compression by meningioma; a junctional scotoma resulting from a tuberculum sellae lesion is also shown Olfactory groove meningioma Tuberculum sellae meningioma Sphenoidal ridge meningioma
- 34. ‘Junctional scotoma’ Junctional scotoma is the visual field defects that arise from damage to the junction of the optic nerve and the optic chiasm. Sellar masses including pituitary tumors are the most common cause of these visual field defects. Visual field shows ipsilateral central scotoma and contralateral superior temporal quadrantanopia (junctional scotoma, JS) It occurs mostly in postfixed chiasma.
- 35. Junctional scotoma: Etiology Lesions that produce the junctional scotoma are typically extrinsic compressive mass lesions at the junction of the optic nerve and the chiasm. Other demyelinating, infectious, inflammatory, infiltrative, traumatic, and other etiologies can occur in this location however.
- 36. Junctional scotoma: Etiology Following are the common cause: • Suprasellar tumors (commonly pituitary adenoma) • Suprasellar meningioma • Craniopharyngioma • Aneurysms of the internal carotid or the anterior communicating artery
- 38. Sphenoid wing meningiomas Sphenoid wing meningiomas are slow growing tumors that originate from outer arachnoid meningeal epithelial cells. Meningiomas can be multiple, particularly when they associated with neurofibromatosis type 2 (NF2).
- 39. Sphenoid wing meningiomas Sphenoid wing meningiomas are classified as either globoid tumors with a nodular shape or an en plaque tumor which is flat and spreads along the entire sphenoid ridge. The globoid tumors include 3 groups depending on their location: inner (medial), middle, and lateral (pterional)
- 40. Sphenoid wing meningiomas Medial sphenoid wing meningiomas have a higher morbidity, mortality, and recurrence rate compared to other meningiomas due to their involvement with anterior visual pathways, anterior intracranial arteries, and the cavernous sinus
- 41. Clinical Features Tumours compress the optic nerve early if the tumour is located medially and late if the lateral aspect of the sphenoid bone and middle cranial fossa are involved. A classic finding in the latter is fullness in the temporal fossa due to hyperostosis
- 43. Investigation MR with gadolinium contrast utilizing multiple planes and thin sections demonstrates the relationship between a mass lesion and the chiasm, and is usually the preferred imaging modality. Adenomas are typically hypointense on T1 and hyperintense on T2 images. CT will demonstrate enlargement or erosion of the sella. Endocrinological evaluation is complex, particularly as combined hormonal over- and under-secretion may be present, and is usually undertaken by an endocrine
- 44. Treatment of pituitary adenomas Observation may be appropriate for incidentally discovered and clinically silent tumours. Medical therapy is usually the initial step and consists of the reduction in tumour size and secretion using agents such as dopamine agonists (e.g. cabergoline and the older bromocriptine) and somatostatin analogues such as octreotide, with supplementary hormonal correction as appropriate.
- 45. Treatment of pituitary adenomas Surgery consists of tumour debulking rather than complete excision and is usually carried out endoscopically via a trans-sphenoidal approach through a gum incision behind the upper lip. Indications include the failure or intolerance of medical management and sometimes decompression for acute visual loss. Visual field improvement is fastest in the earliest weeks and months following surgery.
- 46. Treatment of pituitary adenomas Radiotherapy is rarely employed due to the risk of complications, but is utilized in some circumstances. Newer techniques include intensity-modulated radiation therapy and stereotactic radiosurgery. Monitoring. Long-term ophthalmological review is required, with serial assessment of visual function
- 47. Pituitary apoplexy (PA)/ Sheehan syndrome • Pituitary apoplexy (PA) is caused by acute haemorrhage into or infarction of the pituitary gland, and is usually associated with a previously undiagnosed adenoma; Sheehan syndrome is infarction of the pituitary usually associated with childbirth and is generally regarded as a form of PA. • PA typically manifests with the sudden onset of a severe headache, nausea and vomiting, sometimes with meningism and occasionally reduced consciousness or stroke.
- 48. Pituitary apoplexy (PA)/ Sheehan syndrome • There is often reduced visual acuity and/or a bitemporal hemianopia depending on the anatomical effects of the lesion. • Double vision due to compromise of the adjacent ocular motor nerves is common. Acute hormonal insufficiency can lead to life-threatening complications such as an Addisonian crisis.
- 49. Pituitary apoplexy (PA)/ Sheehan syndrome: Investigation and treatment Investigations include • MR, urgent • visual field testing, and • hormonal assessment. • Acute medical management, including hormone administration and surgical decompression, may be necessary.
- 50. Craniopharyngioma: In children Craniopharyngioma is a slow-growing tumour arising from vestigial remnants of the Rathke pouch along the pituitary stalk. Affected children frequently present with • dwarfism, • delayed sexual development and • obesity due to interference with hypothalamic function.
- 51. Craniopharyngioma: In adults Adults usually present with visual impairment. Visual field defects are complex and may be due to involvement of the optic nerves, chiasm or tracts
- 52. Progression of bitemporal visual field defects caused by compression of the chiasm from above by a craniopharyngioma. LE = left eye; RE = right eye
- 53. • The initial defect frequently involves both inferotemporal fields because the tumour compresses the chiasm from above and behind, damaging the upper nasal fibres. MRI shows a solid tumour that appears isointense on T1 images. Cystic components appear hyperintense on T1 images. • Treatment is mainly surgical, but recurrences are common
- 54. • Magnetic resonance imaging (MRI) is one of the most commonly used tests in neurology and neurosurgery. MRI provides exquisite detail of brain, spinal cord and vascular anatomy, and has the advantage of being able to visualize anatomy in all three planes: axial, sagittal and coronal (see the example image below).
- 55. Axial, Sagittal, Coronal MRI has an advantage over CT in being able to detect flowing blood and cryptic vascular malformations. It can also detect demyelinating disease, and has no beam-hardening artifacts such as can be seen with CT. Thus, the posterior fossa is more easily visualized on MRI than CT. Imaging is also performed without any ionizing radiation
- 56. In general, T1- and T2-weighted images can be easily differentiated by looking the CSF. CSF is dark on T1-weighted imaging and bright on T2- weighted imaging.