Rosen & Barkin's 5-Minute Emergency Medicine Consult (215 page)

• Traumatic diplopia
  
  • Orbital fracture
    
  • Contusions
    
  • Hematoma
    
  • Rarely brainstem contusion or hematoma
    
• Monocular diplopia
  
  • Nearly always due to an intrinsic eye problem
    
  • Corneal surface keratoconus
    
  • Subluxation of the lens
    
  • Structural defect within the eye
    
  • Functional disorders such as conversion disorder, factitious disorder, or somatization.
    
• Nontraumatic binocular diplopia
  
  • Brain and brainstem dysfunction
    
    • Stroke
      
    • Multiple sclerosis
      
    • Cerebral cortical problems (e.g., migraine) are rare
      
  • CN dysfunction
    
    • Aneurysm of posterior communicating artery (CN 3 palsy)
      
    • Chronic lymphocytic meningitis (multiple CN deficits)
      
    • Pseudotumor cerebri (CN 6 palsy)
      
    • Low pressure (spontaneous intracranial hypotension) (CN 6 palsy)
      
  • Bony skull and orbits:
    
    • Tumor
      
    • Thyroid disease
      
    • Inflammation (Tolosa-Hunt)
      
  • Neuromuscular junction (NMJ) of EOMs:
    
    • Myasthenia gravis (MG)
      

DIAGNOSIS

• Determine if the diplopia is following head injury, if it is constant or intermittent and its duration.
  
• Determine if diplopia is monocular or binocular.
  
• Ask about HA or other neurologic or visual symptoms.
  
• Are the 2 images aligned horizontally, vertically, or diagonally?
  

• Differentiate monocular from binocular:
  
  • If the diplopia goes away with covering either eye, it is binocular
    
  • If it persists in one eye, it is monocular (problem in the eye with diplopia)
    
• Differentiate traumatic and nontraumatic diplopia
  
• Monocular diplopia
  
  • Careful ocular exam
    
  • Visual acuity
    
• Binocular diplopia:
  
  • Examine the eye completely (is there ptosis, anisocoria, limitation of EOMs, proptosis, exophthalmos?). Is VA normal?
    
  • CN 3 – pupil involving – diagonal diplopia with ptosis and dilated pupil
    
  • CN 3 – pupil sparing – diagonal diplopia with normal lids and pupils
    
  • CN 4 – vertical or diagonal diplopia, least common of all
    
  • CN 6 – horizontal diplopia; images separate more as gaze goes out laterally on affected side.
    
  • Do a complete neurologic exam
    
• Traumatic diplopia:
  
  • Facial anesthesia
    
  • Anisocoria
    
  • Proptosis
    
  • Decreased visual acuity
    

Accurate history and physical exam are the cornerstones of diagnosis. Establishing a history of trauma is key. In spontaneous cases, the physical exam should be directed at establishing:

• Is the diplopia isolated or not?
  
• If isolated, which CN is involved?
  
• If other neurologic deficits exist, try to localize the site of the lesion.
  
• Some form of cerebral angiography (CTA, MRA, DSA) if there is a CN 3 palsy and dilated pupil.
  

• Lab testing in the ED is not generally useful:
  
  • Occasionally, thyroid function tests are helpful. Other serologic tests (e.g., for myasthenia are not necessary in the ED).
    

• If MG is possible, consider an edrophonium (Tensilon) test or an ice test.
  
• Lumbar puncture – if considering SAH, chronic lymphocytic meningitis, high or low CSF pressure.
  
• Brain and cerebrovascular imaging – if considering mass lesion, aneurysm, stroke, MS. Specific tests depend on the specific differential diagnosis.
  

• Post-traumatic diplopia:
  
  • Orbital fracture/hematoma with direct damage to CNs or hematoma limiting EOM excursions
    
  • Rarely, brainstem contusion affecting CN nuclei or MLF
    
• Monocular diplopia:
  
  • Nearly any ocular problem (corneal, lens, iris, retinal problems, and refractive error)
    
  • Rarely, bilateral monocular diplopia due to cortical dysfunction
    
• Binocular diplopia:
  
  • Brain and brainstem
    
    • Stroke or MS involving the brainstem, often with a nuclear CN palsy or an INO. This pattern is rarely seen after head injury and contusion
      
    • Wernicke encephalopathy
      
    • Rare: “Cortical” diplopia from migraine or irritative lesion and botulism
      
  • CN lesions
    
    • CN palsy due to stretch, contusion, ischemia, CSF inflammation, or abnormal pressure
      
    • CN 3 – KEY to differentiate pupil involving (must r/o aneurysm) vs. pupil sparing (microvascular infarct from diabetes/hypertension).
      
    • CN 6 palsy is a nonlocalizing finding.
      
    • When multiple CNs are involved, think about MG, lymphocytic meningitis, cavernous sinus pathology.
      
    • When medial rectus is involved (decreased adduction) but there is no clear CN 3 palsy, consider INO
      
• Skull and orbits:
  
  • Infiltrative disorders of orbit (thyroid, tumor, abscess, and Tolosa-Hunt)
    
• NMJ:
  
  • MG and botulism
    

TREATMENT

The vast majority of patients with diplopia do not require stabilization. Initial steps are entirely based on the etiology in an individual patient.

• Lumbar puncture:
  
  • In cases of possible lymphocytic meningitis, pseudotumor cerebri, spontaneous intracranial hypotension, do LP. ALWAYS measure the opening pressure.
    
• Edrophonium test:
  
  • In cases of possible MG, consider performing an edrophonium test (see reference Scherer et al. for technique).
    
• Eye patch:
  
  • Consider eye patch in discharged patients for symptom control
    

Same differential diagnosis.

• Pregnant women with hyperemesis gravidarum can get Wernicke encephalopathy or orbital hemorrhage, both of which can present with diplopia.
  
• Postpartum women can develop diplopia due to cavernous sinus thrombosis, postdural puncture headache, or orbital hemorrhage.
  

FOLLOW-UP

• Admission is predicated upon the cause.
  
• Many patients are admitted to facilitate a rapid workup for serious causes (including advanced brain and vascular imaging and specialty consultation.
  

Most patients with monocular diplopia or with traumatic diplopia whose cause is
clearly established
and does not require urgent surgery can be safely discharged.

All patients who are discharged with diplopia will require some form of follow-up, usually with either a neurologist or ophthalmologist.

• Diplopia can present as “blurred vision” if the 2 images are not far off from one another.
  
• Never assume diplopia is an isolated cranial neuropathy without doing a very careful neurologic exam.
  
• Check pupils to avoid missing a cerebral aneurysm. Aneurysmal CN 3 palsies are often due to
  unruptured
  aneurysm (CT and LP normal).
  
• MG can present with intermittent diplopia. The pupils are
  always
  normal.
  
• Test facial sensation; hypoesthesia and diplopia localize the lesion to the cavernous sinus or superior orbital fissure.
  
• Test vision; decreased VA and diplopia are often an orbital or superior orbital fissure lesion (may be surgical emergency!)
  

• Brazis PW. Isolated palsies of cranial nerves III, IV, and VI.
  Semin Neurol
  . 2009;29:14–28.
  
• Buracchio T, Rucker JC. Pearls and oysters of localization in ophthalmoparesis.
  Neurology
  . 2007;69:E35–40.
  
• Pelak VS. Evaluation of diplopia.
  Hospital Practice.
  2004;3:16–25.
  
• Scherer K, Bedlack RS, Simel DL. Does this patient have myasthenia gravis?
  JAMA.
  2005;293:1906–1914.
  
• Tilikete C. When is diplopia strongly suggestive of a vascular event?
  Exp Rev Ophthal
  . 2009;4(4):357–361.
  

See Also (Topic, Algorithm, Electronic Media Element)