Double Vision Flashcards
What causes double vision?
Results from two eyes not moving synchronously together
What is Ophthalmoplegia or Ophthalmoparesis?
Weakness of eye movements
What is all weakness d/t?
- Myopathy
- NMJ disorder
- UMN or LMN lesions
Any lesion of visual pathway ANTERIOR to optic chiasm produce ____ ____ ____.
Monocular visual distrubances
Any lesion POSTERIOR to optic chiasm produces ___ ___ ___ ___.
Hemianoptic visual field disturbances
What is Marcus Gunn pupil?
Afferent pupillary defect
Dilation in eye w/ light shining into it (swinging light test)
What does an optic chiasm lesion produce?
Bitemporal hemianopsia
What is the hx of a myopathy?
- Subacute or chronic
- Other weak muscles
- Thyroid dz
- Mitochondrial myopathies
What are the PE findings of myopathy?
- Dysconjugate eye movements causing diplopia
- Pupil is NEVER affected
- Findings of thyroid dz
What are the PE findings of thyroid dz?
- Myxedema
- Exophthalamous
- Slow relaxation phase of DTRs
- Hair loss
- Brittle nails
What are the presenting features in >90% if Myasthenia Gravis cases?
Diplopia &/or Ptosis
Who gets Myasthenia Gravis?
Young females & older males
What is the course of Myasthenia Gravis?
Subacute or chronic w/ waxing & wanning of sx
What are the PE findings of Myasthenia Gravis?
- Ptosis
- Diplopia
- Pupil is NEVER affected
- Dysarthria/dysphagia
- Facial, axial or limb weakness
- Normal DTRs & sensation
What dramatically improves Myasthenia Gravis sx?
IV injection of Endrophonium (Tensilon) a short acting acetylcholinesterase drug
What is Myasthenia gravis?
AI dz in which auto-Ab’s directed at post-synaptic Ach receptors at NMJ
What is the tx for Myasthenia gravis?
- Acetylcholinesterase drugs
- Corticosteroids
- Immuosuppressive drugs
- Thymectomy if tumor or hyperplasia
How can the Oculomotor nerve be damaged?
Mass lesion compressing b/w the edge of the tentorium & brainstem (herniation of the uncus of the temporal lobe) or by hematoma, neoplasm, etc
What is the first thing that occurs in oculomotor nerve damage?
Dilation of pupil d/t peripheral PSN autonomic fibers followed by Opthalmoplegia of all the CN III innervated eye muscles
What are the sx of Oculomotor nerve lesion?
- Acute onset
- Diplopia & ptosis of same eye
- No waxing/waning
- Multiple vascular RF
What are the Vascular RF?
- Advanced age
- DM
- HTN
- Hyperlipidemia
- Smokers
- Vasculitis
What is Ipsilateral Ophthalmoplegia?
- Adduction is impaired
- Abduction is intact
- Pupil is unaffected
What are the technological features of Oculmotor nerve lesion?
Brain MRI scans are normal or reveal incidental ABN
What is the tx for Oculomotor nerve lesion?
- Eye patch to reslove diplopia
- Watchful waiting
- RF reduction
What are the PE findings of Abducens nerve lesion?
- Ophthalmoparesis is paralysis/weakness of abduction w/ all extraocular fxn intact
- Weakness, sensory loss, AMS, HA or papilledema if inc ICP or compressing CN VI
What are the technological features of Abducens nerve lesion?
Brain imaging evidence of cause of inc ICP or indications of vascular RF
What is the onset of Ophthalmoplegia?
- Acute–Vascular in elderly
- Subacute–Demyelinating in young
- Gradual–Neoplastic
What are the PE findings of Opthalmoplegia?
- Unilateral or bilateral
- Horizontal eye movements the adducting eye cannot cross the midleine & abducting eye develops nystagmus
What are the technological features of Internuclear Ophthalmoplegia?
Brain MRI w/ & w/o contrast ID lesion in the pons b/w the nucleus of CN III & CN VI
What is the hx of Wernicke’s Encephalopathy?
Alcoholism & nutritional def or other cond assoc w/ thiamine def such as gastric surgery & failure to take thiamine supplements
What are the sx of Wernicke’s Encephalopathy?
- Memory loss
- Diplopia
- Numbness & tingling
- Confabulation
- Ataxia
- Peipheral neuropathy
What are the tech features of Wernicke’s Encephalopathy?
MRI evidence of scattered deep white matter brain changes in upper brainstem & diencephalon or normal MRI
What is the 1st finding to clear after giving IV thiamine to a Werneicke’s Encephalopathy pt?
Ophthalmoplegia
