Common Neuro-Ophthalmic Pitfalls (Case-Based Teaching)

✍ Scribed by Valerie A. Purvin

• Publisher: Cambridge University Press
• Year: 2009
• Tongue: English
• Leaves: 235
• Edition: 1
• Category: Library

✦ Synopsis

Using real-life cases describing patients with neuro-ophthalmic disorders, this book is a case-based teaching tool that bridges the gap between textbook information and everyday clinical practice. Each case illustrates a particular area of frequent diagnostic confusion, and highlights the specific clinical features that should point to the correct diagnosis. Focusing on errors in this way serves as motivation to the clinician to master the material so that 'pitfalls' can be avoided. The level of the case discussions assumes that the reader has some familiarity with basic neuroanatomy, physiology and disease process but each case discussion furnishes a brief review of such information, always with an emphasis on those features that are clinically relevant. The case-histories are succinct and amply illustrated, including motility and fundus photographs, visual fields and radiographic studies. The narrative is moved along with questions to the reader, making it easy to follow the logic of the cases.

✦ Table of Contents

Cover
Half-title
Title
Copyright
Contents
Foreword
Preface
Acknowledgements
1 When ocular disease is mistaken for neurologic disease
Double images
What important piece of historical information is still missing in this case?
What maneuver might be helpful for confirming our suspicion that this patient’s double vision is ocular in nature?
Diagnosis: Monocular diplopia due to cataract
Headache and bilateral disc edema
What test was done and what was the diagnosis?
Diagnosis: Malignant hypertension
Chronic optic neuropathy
Having excluded compressive, inflammatory and infiltrative causes of optic neuropathy, what othermechanisms would you consider? How would you proceed?
Diagnosis: Glaucomatous optic neuropathy
Painful mydriasis
What clues suggest an alternative diagnosis?
Diagnosis: Acute angle closure glaucoma
Invisible retinal disease
Twinkling scotoma
What aspect of this patient’s positive visual phenomenon is highly atypical for migraine?
Diagnosis: Acute idiopathic blindspot enlargement
Sudden monocular visual loss with normal fundus
What othermechanism of visual loss would you consider? Are there any historical features that are helpful here?
Whymight a retinal stroke not have been apparent on examination?
Hazy night vision
What specific aspect of this patient’s history suggests the correct localization of his visual problem?
Diagnosis: Hypovitaminosis A
Swirling vision
Diagnosis: Cancer-associated retinopathy
Episodic monocular blur
This patient’s work-up addressed the possibility of retinal vascular disease as the cause of his transientmonocular visual loss (TMVL). Is there something about his history, however, to suggest a different mechanism for his episodes?
Diagnosis: Transientmonocular visual loss due to corneal decompensation
FURTHER READING
Monocular diplopia
Hypertensive retinopathy
Twinkling scotoma
Central retinal artery occlusion
Hypovitaminosis A
Cancer-associated retinopathy
Corneal decompensation
Glaucoma
2 When orbital disease is mistaken for neurologic disease
Incidental elevation deficit
What othermechanism could account for this patient’s abnormal ocularmotility besides a third nerve palsy?
Diagnosis: Orbital floor fracture with muscle entrapment
Painless vertical diplopia
What clinical features help to localize the source of this patient’s ocularmotility disorder?
Diagnosis: Euthyroid Graves’ disease
Fatigable ptosis
How is lid fatigability objectively demonstrated?
What other forms of ptosismight share a similar history of worsening with sustained use?
Diagnosis: Levator dehiscence
Painful ptosis and diplopia
What is the anatomic significance of a superior division palsy?
The investigation thus far has revealed no intracranial pathology. How would you proceed?
Diagnosis: Idiopathic orbitalmyositis
Painful optic neuropathy
Is this patient’s clinical course consistent with a diagnosis of optic neuritis?
What specific feature of her clinical course raises the possibility of orbital disease?
Diagnosis: Idiopathic optic perineuritis
FURTHER READING
Orbital examination and restrictive orbitopathy
Levator dehiscence
Painful ptosis and diplopia
Optic perineuritis
3 Mistaking congenital anomalies for acquired disease
Headaches and elevated discs
Inferior altitudinal visual field defects
Are there clues to the correct diagnosis in this case?
Diagnosis: Superior segmental hypoplasia
Incidental abduction deficit
What feature identifies this woman’s abduction deficit as a congenital, rather than acquired, sixth nerve palsy?
Diagnosis: Type I Duane’s syndrome
Intermittent vertical diplopia
What other causes of fourth nerve palsy should be considered?
How would you pursue a diagnosis of congenital fourth nerve palsy in this patient?
Diagnosis: Congenital fourth nerve palsy
FURTHER READING
Pseudopapilledema
Superior segmental hypoplasia
Duane’s syndrome
Congenital superior oblique palsy
4 Radiographic errors
Ordering the wrong scan
Progressive optic neuropathy
Is there a problem with the diagnosis of “chronic optic neuritis”?
What clinical features in this case suggest the likely mechanism of her chronic optic neuropathy?
What additional radiographic evaluation should be obtained?
Diagnosis: Optic nerve sheathmeningioma
Headache and papilledema
Diagnosis: Cerebral venous sinus thrombosis
Idiopathic ptosis and miosis
Why is the current study incomplete?
Diagnosis: Postganglionic Horner syndrome
Subtle radiographic findings
"Boxer" ptosis
The above clinical findings are characteristic of a postganglionic Horner syndrome. Howmight this be related to her preceding trauma?
Diagnosis: Internal carotid artery dissection
Headache and bilateral third nerve palsy
What is the diagnosis? What confirmative study would you order?
Diagnosis: Pituitary apoplexy
Progressive sixth nerve palsy
What aspect of this patient’s presentation provides the most compelling diagnostic clue?
Diagnosis: Petrous ridge meningioma
Midline and bilateral abnormalities
Bilateral idiopathic sixth nerve palsy
Is a diagnosis of vasculopathic sixth nerve palsy still tenable here?
What are the most common causes of bilateral sixth nerve palsy and what mechanism ismost likely in this case?
Diagnosis: Clivus tumor
Atypical pseudotumor cerebri syndrome
What features of this case are atypical for a diagnosis of IIH? What alternative diagnosis should be considered?
Diagnosis: Superior sagittal sinus thrombosis
Vertical diplopia
Diagnosis: Symmetric Graves’ disease
FURTHER READING
Neuro-imaging
Canalicular meningioma
Cerebral venous thrombosis
Horner syndrome and carotid dissection
Chronic sixth nerve palsy
5 Incidental findings (seeing but not believing)
Empty sella
Low cerebellar tonsils
Sphenoid sinus mucocele
Dolichoectatic basilar artery
FURTHER READING
Pseudotumor cerebri syndrome
Chiari malformation
Sphenoid sinus mucocele
Dolichoectatic basilar artery
6 Failure of pattern recognition
Painful ophthalmoplegia
Where is this patient’s lesion?
Diagnosis: Tolosa Hunt syndrome
Painful ophthalmoplegia and visual loss
Based on the clinical findings, where is the lesion?
Diagnosis: Orbital apex syndrome
Painless diplopia
What is thismotility pattern, and what does it tell you about the mechanism of the patient’s diplopia?
Diagnosis: Oculomotor nerve palsy with aberrant regeneration
Right-sided visual field loss
What is the significance of this visual field pattern? Does it help to illuminate the findings on her MRI?
Diagnosis: Lateral geniculate body stroke
FURTHER READING
Painful ophthalmoplegia
Orbital apex syndrome
Third nerve misdirection
Lateral geniculate body
7 Clinical findings that are subtle
Painless central gray spot in a teenager
What is the most likely cause of this patient’s neuroretinitis, and how would you test for it?
Diagnosis: Neuroretinitis due to cat scratch disease
Chronic "pink eye"
This patient had an additional non-ocular symptom which she did not volunteer because she didn’t think it was relevant to her eye problem, yet this symptom was an important clue to the correct diagnosis. What question should be asked?
Diagnosis: Dural-cavernous fistula
Bouncing vision
What is her symptom of “bouncing vision” called and what physical finding would you look for on examination?
This patient’s eye examination, however, was normal, specifically nystagmus was not observed. Why not?
What examination techniques can help in the detection of nystagmus when the oscillatory amplitude is particularly small?
Diagnosis: Downbeat nystagmus due to Chiari I malformation
Farmer with an adduction deficit
Diagnosis: Myasthenic pseudo-INO
FURTHER READING
Neuroretinitis
Dural-cavernous fistula
Downbeat nystagmus
8 Misinterpretation of visual fields
Abnormal field and night blindness
How would you describe this patient’s visual field defect? What diagnoses should be considered?
Diagnosis: Retinitis pigmentosa
Constricted fields after herniation
What bedside test can help distinguish non-organic field loss from true constriction of the visual field?
Diagnosis: Bilateral occipital stroke with macular sparing
Sudden difficulty reading the paper
What simple “bedside” test could be performed to further investigate this patient’s symptom?
Diagnosis: Small homonymous scotoma due to occipital stroke
Post-cardiac bypass visual loss
Is there another possible explanation for this patient’s visual loss, and how would you investigate this alternative mechanism?
Diagnosis: Bilateral homonymous hemianopic scotomas secondary to bilateral occipital tip strokes
Pseudo-bitemporal defects
Incidental field defect
What is the next step in this patient’s evaluation?
Based on the new interpretation of this patient’s visual field defect, what feature of the examination should be reconsidered?
Diagnosis: Tilted disc syndrome
Abnormal fields and temporal disc pallor
Diagnosis: Dominant optic atrophy
Abnormal field and photopsias
What aspect of this patient’s visual field defect is atypical for chiasmal compression and suggests instead an ocular disorder?
Diagnosis: Rod-cone dystrophy
FURTHER READING
Visual field testing
Tilted disc syndrome
Dominant optic atrophy
9 Neuro-ophthalmic look-alikes
Idiopathic optic neuritis vs. Leber's hereditary optic neuropathy
Based on this patient’s clinical presentation, what is your first diagnostic consideration?
Does his clinical course change your mind about the diagnosis?
Was there a “red flag” at the time of his initial presentation?
Acute tonic pupil vs. pharmacologic mydriasis
What commonmechanisms of injury could explain this patient’s pupillary dysfunction?
What examination finding can distinguish pharmacologic blockade from postganglionic denervation of the iris sphincter?
Chronic tonic pupils vs. Argyll Robertson pupils
Is there a physical finding that can differentiate chronic Adie’s pupils from Argyll Robertson pupils?
Convergence spasm vs. bilateral sixth nerve palsies
What clinical findings would support a diagnosis of convergence spasm?
Wernicke's encephalopathy vs. brainstem stroke
What aspect of this casemakes an acute brainstem stroke unlikely?
What metabolic abnormality can produce this clinical picture?
Chronic progressive external ophthalmoplegia vs. progressive supranuclear palsy
This combination of horizontal and vertical gaze limitation with slowed saccades could be due to either supranuclear gaze palsy or ocular myopathy. How can we distinguish these two mechanisms?
Orbital myositis vs. sixth nerve palsy
This patient’s right abduction deficit suggested a sixth nerve palsy. What othermechanism might be responsible and what clinical features suggest this alternative cause?
FURTHER READING
Optic neuritis vs. Leber’s hereditary optic neuropathy
Acute unilateral mydriasis
Light near dissociation
Convergence spasm
Wernicke’s encephalopathy
Progressive supranuclear palsy
Sixth nerve palsy vs. orbital myositis
10 Over-reliance on negative test results
Unexplained visual loss
In the absence of any objective abnormalities, would you consider that thismight be non-organic visual loss, perhaps due to job-related stress?
Visual loss due to nutritional deficiency was suspected based on hermacrocytosis, however her serum B12 level was within the normal range. What would you like to do next?
Diagnosis: Pernicious anemia with normal serum B12 level
Twinkling after embolic stroke
Now we understand the basis of this patient’s visual field defect. But what is causing her persistent photopsias?
Diagnosis: Digoxin toxicity with therapeutic levels
Painless ptosis and diplopia
Diagnosis: Ocularmyasthenia
Headache and third nerve palsy
Which diagnostic possibilities should be addressed first?
What additional test should be obtained?
Diagnosis: Aneurysmal third nerve palsy
Truly negative neuro-imaging
Brainstem syndrome with negative scan
Can you localize this patient’s lesion?
What is the most likely etiology in this patient and how would you proceed with the evaluation?
Diagnosis: One-and-a-half syndromesecondary to a clinically isolated demyelinating event
Homonymous hemianopia with negative neuro-imaging
What disease processes would you consider here?
Diagnosis: Creutzfeldt–Jakob disease (Heidenhain variant)
Non-dominant parietal lobe syndrome with negative neuro-imaging
Can you localize this patient’s problem?
Diagnosis: Visual variant of Alzheimer’s disease
Progressive third nerve palsy
What other investigations might be helpful?
Diagnosis: Third nerve palsy secondary to nasopharyngeal carcinoma
Upgaze palsy
What do youmake of this patient’s negative neuro-imaging in light of her clinical presentation?
Diagnosis: Shunt malfunction in the absence of ventriculomegaly
FURTHER READING
Vitamin B12 deficiency
Digoxin toxicity
Myasthenia
Aneurysmal third nerve palsy
One-and-a-half syndrome
Cortical visual loss with negative neuro-imaging
Skull base tumors with negative imaging
Shunt failure with negative neuro-imaging
11 Over-ordering tests
Isolated unilateral mydriasis
This patient’s acute unilateralmydriasis raised the possibility of third nerve palsy due to a posterior communicating artery aneurysm, and the work-up was directed with this possibility in mind. Can isolated mydriasis, in fact, be a sign of a posterior…
If an isolated, enlarged and poorly reactive pupil is not a sign of a pCOM aneurysm, what other causes should be considered?
Diagnosis: Adie’s tonic pupil
Acute unilateral visual loss with disc edema
Can you diagnose the cause of this patient’s acute monocular visual loss based on the clinical findings? Are ancillary tests needed?
Diagnosis: Non-arteritic anterior ischemic optic neuropathy (NAION)
Acute isolated sixth nerve palsy
What is the most likely diagnosis and what evaluation would be appropriate?
Diagnosis: Vasculopathic cranial mononeuropathy
Episodic scintillating scotoma
Does this patient need neuro-imaging? An EEG? Other investigation?
Diagnosis: Migraine aura
Unexplained visual loss
What feature in this case suggests nonorganic visual loss? Is additional ancillary testing needed?
Diagnosis: Non-organic visual loss
FURTHER READING
Adie’s tonic pupil
Non-arteritic anterior ischemic optic neuropathy
Vasculopathic cranial mononeuropathy
Migraine
Non-organic visual loss
12 Management misadventures
Management of idiopathic intracranial hypertension
Evaluation and treatment of giant cell arteritis
Overzealous treatment of blood pressure in NAION
Prednisone for demyelinating optic neuritis
Over-reliance on pyridostigmine bromide (Mestinon) in ocular myasthenias
Failure to provide symptomatic treatment
FURTHER READING
Idiopathic intracranial hypertension
Giant cell arteritis
Non-arteritic anterior ischemic optic neuropathy
Optic neuritis
Ocular myasthenia
Nystagmus
Index