Common Neuro-Ophthalmic Pitfalls: Case-Based Teaching

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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