NEURO-OPHTHALMIC ASSESSMENT DR. B. C. UGWU

Transcription

1 CLINICAL VIGNETTE 2019; 5:1 NEURO-OPHTHALMIC ASSESSMENT DR. B. C. UGWU Editor-in-Chief: Prof Olufemi Idowu Neurological surgery Division, Department of Surgery, LASUCOM/LASUTH, Ikeja, Lagos, Nigeria. Copyright- Frontiers of Ikeja Surgery 2019; Volume 5:1

2 NEURO-OPHTHALMIC ASSESSMENT DR. B. C. UGWU Eye Foundation Hospital, GRA, Ikeja, Lagos

3 OUTLINE Introduction History Examination i) General and systemic ii) Ocular Investigations i) visual fields ii)neuroimaging iii) B-scan iv)visual evoked potential v) optical coherence tomography vi) other investigations References

4 INTRODUCTION Neuro-ophthalmological assessment involves history, examination and investigations aimed at diagnosing a neuro-ophthalmic pathology Not to be seen as an independent process, but complementary to full neurological assessment

5 HISTORY Blurry vision, Transient obscuration or loss of vision, Diplopia, Ptosis, Scotomas, Proptosis Ocular pain especially on eye movement Nystagmus, Ocular deviation Amenorrhoea or oligo-menorrhoea, galactorrhoea, severe post partum haemorrhage, Gynaecomastia, Headaches, vomiting, head trauma Systemic diseases-hypertension, Diabetes mellitus, Systemic lupus erythematosus, Rheumatoid arthritis, multiple sclerosis Drug history-ethambutol

6 GENERAL EXAMINATION Head posture- head tilt, chin lift, Thickened superficial temporal artery Pallor Thyroid mass Features of acromegaly- acral and tongue enlargement SYSTEMIC EXAMINATION NEUROLOGICAL EXAMINATIONS

7 OPTIC NERVE Visual acuity- Snellen chart (at 6 m); Jaeger or Rosenbaum chart (hand-held card, at 30 cm); +/- pin hole test (tiny 2 mm perforation- improve vision indicates refractory error); Count fingers; Hand movement; Light perception Pupils- swinging flashlight test- Marcus Gunn pupil- relative afferent pupillary defect; Multiple sclerosis, Diabetes mellitus Horner s syndrome- (miosis, enophthalmos, partial ptosis, anhidrosis); Argyll Robertson- unreactive irregular small pupil, normal accommodation in tertiary syphilis, DM; Pontine Holmes-Adie syndrome- unilateral dilated pupil, slow light reflex, normal accommodation, absent knee jerks (benign); DM; Temporal lobe herniation Visual Field- Confrontational vs automated; central, peripheral Fundoscopy- Disc and retina

8 FUNDUSCOPY Size, cup disc ratio, colour, oedema, congenital abnormalities, Flat/elevated/ tilted, Haemorrhages, retinociliary collateral vessels, Papilledema is bilateral disc oedema caused by raised ICP

9 OCULAR EXAMINATION Lids and orbit-ptosis, proptosis Ocular alignment-exotropia or exotropia, hypertropia or hypotropia Extraocular muscles;

10 OCULOMOTOR NERVE PALSY Diplopia-worse on contralateral gaze Ptosis, Limited elevation and adduction so that the eye is turned out and down due to unopposed actions of Superior Oblique & Lateral Rectus CN III Palsy-pupil affected or pupil sparing(medical vs surgical)

11 SIGNS OF CN IV PALSY Hypertropia of the affected side, "worse on opposite gaze"- WOOG Limitation of depression most marked on abduction Extorsion to the ipsilateral side Diplopia vertical or torsional, worse on downward gaze Contralateral Head tilt to compensate for lack of intorsion Exclude bilateral invovlment- crossed hypertropia, excyclotorsion of 10 degrees or more, and a large V-pattern of strabismus Deviation is "better on opposite tilt" BOOT SIGNS OF CN VI PALSY Esotropia Horizontal diplopia Abduction deficit Compensatory head turn to the side of the lesion

12 INVESTIGATIONS- VISUAL FIELDS Practically all VF info lies in central 30 degrees Covers 66% of the ganglion cells Corresponds to 83% of the visual cortex

13 RELIABILITY INDICES 10% of the stimuli are used at random to test the patient s cooperation False Positive errors>20%- unreliable False Negative errors>20%- unreliable Fixation losses >33%- unreliable

14

15

16 RADIOLOGICAL INVESTIGATIONS Computer Tomography Scan Magnetic resonance imaging- Measure optic nerve sheath diameter in papilledema ( mm) Idiopathic intracranial Hypertension slit-like ventricles & flattening of the pituitary gland ( empty sella sign) are found B-Scan- to measure optic nerve sheath diameter in papilledema, measured at 3mm behind the optic nerve head, values > 5mm is high

17 VISUAL EVOKED POTENTIAL (VEP) Measures the electrical signal generated at visual cortex in response to visual stimulation Depends on the integrity of the visual pathway Stimulus- flash of light (flash VEP) or a black-and-white checkerboard pattern on a screen (pattern VEP) Latency (delay) and amplitude are assessed It contains a prominent positive component P100 and 2 negative components P70 and P135 Can be used as a rough measure of VA in children & uncooperative patients VEP Parameters altered in Optic neuritis Ischemic optic neuropathies Multiple sclerosis Cortical blindness Compressive optic lesions

18 OPTICAL COHERENCE TOMOGRAPHY (OCT) Non invasive imaging that utilizes the principle of Michelson interferometry Can quantify nerve fibre layer and ganglion cell losses Measurements of Retina Nerve Fibre Layer (RNFL) thickness are shown in Temporal, Superior, Nasal, Inferior, Temporal (TSNIT) orientation and are compared to age matched normal Green area- 5 th -95 th percentile by age, yellow area is 1 st -5 th percentile and red area is below the 1 st percentile RNFL thickness map/ optic nerve head map should have a bow tie pattern Indications-optic atrophy/neuropathy, optic disc oedema

19 OTHER INVESTIGATIONS Blood sugar levels : To rule out diabetic papillopathy Serum Lipid profile and Serum Homocysteine levels-non- Arteritic Anterior Ischaemic Optic neuropathy (N-AION) ESR and CRP : Marker of inflammation : (Arteritic-AION) Temporal artery biopsy : Giant cell arteritis (A-AION) Cerebrospinal fluid examination : CSF Opening pressure increased in Idiopathic intracranial hypertension, microscopic examination in Multiple sclerosis

20 REFERENCES Kanski clinical ophthalmology -8 th Ed Miller NR, Newman NJ, Biousse V, Kerrison JB. Walsh and Hoyt s clinical neuro ophthalmology. 6 th ed. 2005, Lippincott Williams & Wilkins. Walsh TJ. Neuro ophthalmology clinical signs and symtopms. 4thed Mosby, Williams & Wilkins. Schiefer U, Wilhelm H, Hart WM. Clinical Neuro ophthalmology, a practical guide. 2007, Springe