Fourth nerve palsy: Difference between revisions
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**Intorts, depresses and abducts the globe
**Intorts, depresses and abducts the globe
*Trochlear nerve palsy causes an inability to move the eye in inward rotation, downward, and laterally. <ref name="rosen">Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Philadelphia, PA: Mosby/Elsevier; 2013</ref>
*Trochlear nerve palsy causes an inability to move the eye in inward rotation, downward, and laterally. <ref name="rosen">Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Philadelphia, PA: Mosby/Elsevier; 2013</ref>
*Most common cause of vertical diplopia <ref name="medscape">Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015</ref>
*Most common cause of vertical [[diplopia]] <ref name="medscape">Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015</ref>


===Etiology===
===Etiology===
*[[Head trauma]] <ref name="book">Disorders of Ocular Movement and Pupillary Function In: Adams and Victor's Principles of Neurology. 10th ed. Accessed on AccessMedicine.com on 8/29/2015. Chapter 14 </ref>
*[[Head trauma]] <ref name="book">Disorders of Ocular Movement and Pupillary Function In: Adams and Victor's Principles of Neurology. 10th ed. Accessed on AccessMedicine.com on 8/29/2015. Chapter 14 </ref>
*Mechanisms that increase intraocular pressure
*Mechanisms that increase intraocular pressure
**Practically never involved by aneurysm
**Practically never caused by aneurysm
*[[Herpes zoster]] opthalmicus
*[[Herpes zoster]] ophthalmicus
*[[Meningitis]]
*[[Meningitis]]
*Diabetic neuropathy
*Diabetic neuropathy
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==Clinical Features==
==Clinical Features==
*Vertical, torsional, or oblique diplopia.
*Vertical, torsional, or oblique [[diplopia]].
**Worse on downward gaze and gaze away from affected muscle <ref name="medscape">Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015</ref>
**Worse on downward gaze and gaze away from affected muscle <ref name="medscape">Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015</ref>
*Head-tilt
*Head-tilt
**Tilt typically away from affected side (~70%) to overcome inward rotation of affected eye to create wider separation of images. Can be paradoxical, where patient tilts head toward affected side (~3%) <ref name="rosen">Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Philadelphia, PA: Mosby/Elsevier; 2013</ref> <ref name="brazis">Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14</ref>
**Tilt typically away from affected side (~70%) to overcome inward rotation of affected eye to create wider separation of images. Can be paradoxical, where patient tilts head toward affected side (~3%) <ref name="rosen">Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Philadelphia, PA: Mosby/Elsevier; 2013</ref> <ref name="brazis">Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14</ref>
**Bielschowsky phenomenon - head tilt to affected side reveals inability to intort, diplopia
**Bielschowsky phenomenon - head tilt to affected side reveals inability to intort, diplopia
*Ask about history of fever, stiff neck, headache, diabetes, hypertension, other sensory and motor symptoms
[[File:trochlear nerve palsy.jpg|thumbnail]]
[[File:trochlear nerve palsy.jpg|thumbnail]]


==Differential Diagnosis==
==Differential Diagnosis==
*''Increased intracranial pressure (ICP)'': [[Pseudotumor cerebri]]  
*''Increased intracranial pressure (ICP)'': [[Pseudotumor cerebri]]  
*''Vascular'': [[Stroke (main) | Stroke]], [[subarachnoid hemorrhage]], aneurysm (extremely rare), microvasculopathy signs and symptoms to diabetes, atherosclerosis or hypertension<ref name="brazis">Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14</ref>
*''Vascular'': [[Stroke (main) | Stroke]], [[subarachnoid hemorrhage]], aneurysm (extremely rare), microvasculopathy from diabetes, atherosclerosis or hypertension<ref name="brazis">Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14</ref>
*''Neoplastic'': Tumor in the subarachnoid space  
*''Neoplastic'': [[Intracranial mass|Tumor]] in the subarachnoid space  
*''Degenerative/deficiency'': Vitamin B deficiency, [[Wernicke-Korsakoff syndrome]]
*''Degenerative/deficiency'': [[Vitamin B12 deficiency]], [[Wernicke-Korsakoff syndrome]]
*''Idiopathic'': Most common cause of acquired trochlear nerve palsy.  
*''Idiopathic'': Most common cause of acquired trochlear nerve palsy.  
*''Infection'': [[Meningitis]], [[herpes zoster]]
*''Infection'': [[Meningitis]], [[herpes zoster]]
*''Congenital'': Signs/symptoms of dysgenesis of trochlear nerve nucleus or abnormal peripheral nerve
*''Congenital'': Dysgenesis of trochlear nerve nucleus or abnormal peripheral nerve
*''Autoimmune'': [[Myasthenia gravis]], [[multiple sclerosis]], [[systemic lupus erythematosus]], [[giant cell arteritis]], [[Sjogren’s]]
*''Autoimmune'': [[Myasthenia gravis]], [[multiple sclerosis]], [[systemic lupus erythematosus]], [[giant cell arteritis]], [[Sjogren’s]]
*''Trauma'': Its long course makes it susceptible to traumatic injury. [[Head trauma (adult)]] is the second most common cause. Is generally severe with loss of consciousness. Consider underlying structural abnormalities if results after minor trauma.  
*''Trauma'': Its long course makes it susceptible to traumatic injury. [[Head trauma (adult)]] is the second most common cause. Is generally severe with loss of consciousness. Consider underlying structural abnormalities if results after minor trauma.  
*''Endocrine'': Thyroid ophthalmopathy <ref name="medscape">Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015</ref> <ref name="brazis">Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14</ref>  
*''Endocrine'': [[Thyroid]] ophthalmopathy <ref name="medscape">Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015</ref> <ref name="brazis">Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14</ref>  
*[[Third nerve palsy]]
*[[Third nerve palsy]]
*[[Abducens nerve palsy]]
*[[Abducens nerve palsy]]
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*+/- LP after negative neuroimaging if suspect subarachnoid hemorrhage or meningitis.  
*+/- LP after negative neuroimaging if suspect subarachnoid hemorrhage or meningitis.  
===Imaging===
===Imaging===
*CT Head if traumatic, suspect stroke, or subarachnoid hemorrhage (rare).
*[[CT Head]] if traumatic, suspect stroke, or subarachnoid hemorrhage (rare).
*MRI is study of choice, although there no increased yield from MRI vs CT scan. <ref name="medscape">Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015</ref> <ref name="brazis">Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14</ref>
*MRI is study of choice, although there no increased yield from MRI vs CT scan. <ref name="medscape">Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015</ref> <ref name="brazis">Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14</ref>


==Management==
==Management==
*Address any acute causes like stroke, trauma
*Address underlying acute pathology
*May require surgical correction
*May require surgical correction
*+/- Neurology consult
*+/- Neurology consult


==Disposition==
==Disposition/Follow-up==
*'''Vasculopathic''': Observation for improvement over 6-8 weeks. Often resolve spontaneously in 4-6 months.
*'''Vasculopathic''': Observation for improvement over 6-8 weeks. Often resolve spontaneously in 4-6 months.
*'''Traumatic''':  Observation for improvement over 6-8 weeks. Often resolves spontaneously. If progressing or lack of improvement – neuroimaging with MRI  
*'''Traumatic''':  Observation for improvement over 6-8 weeks. Often resolves spontaneously. If progressing or lack of improvement – neuroimaging with MRI  

Revision as of 16:23, 8 September 2019

Background

  • Also called the 4th cranial nerve (CN IV)
  • Trochlea innervates superior oblique muscle
    • Intorts, depresses and abducts the globe
  • Trochlear nerve palsy causes an inability to move the eye in inward rotation, downward, and laterally. [1]
  • Most common cause of vertical diplopia [2]

Etiology

Clinical Features

  • Vertical, torsional, or oblique diplopia.
    • Worse on downward gaze and gaze away from affected muscle [2]
  • Head-tilt
    • Tilt typically away from affected side (~70%) to overcome inward rotation of affected eye to create wider separation of images. Can be paradoxical, where patient tilts head toward affected side (~3%) [1] [4]
    • Bielschowsky phenomenon - head tilt to affected side reveals inability to intort, diplopia
Trochlear nerve palsy.jpg

Differential Diagnosis

Evaluation

Labs and Tests

  • +/- POC glucose, CBC, and other labs depending on suspected diagnosis
  • +/- LP after negative neuroimaging if suspect subarachnoid hemorrhage or meningitis.

Imaging

  • CT Head if traumatic, suspect stroke, or subarachnoid hemorrhage (rare).
  • MRI is study of choice, although there no increased yield from MRI vs CT scan. [2] [4]

Management

  • Address underlying acute pathology
  • May require surgical correction
  • +/- Neurology consult

Disposition/Follow-up

  • Vasculopathic: Observation for improvement over 6-8 weeks. Often resolve spontaneously in 4-6 months.
  • Traumatic: Observation for improvement over 6-8 weeks. Often resolves spontaneously. If progressing or lack of improvement – neuroimaging with MRI
  • Isolated, idiopathic cases very rarely have an underlying etiology after prolonged follow-up, and most resolve spontaneously in weeks to months. If no improvement in 2 months, consider neuroimaging. [4]

See Also

External Links

Medscape: Trochlear Nerve Palsy

References

  1. ↑ 1.0 1.1 Marx JA, Hockberger RS, Walls RM, et al., eds. Rosen's Emergency Medicine: Concepts and Clinical Practice. Philadelphia, PA: Mosby/Elsevier; 2013
  2. ↑ 2.0 2.1 2.2 2.3 Sheik Z. Trochlear Nerve Palsy Treatment and Management on emedicine.medscape.com/article/1200187 Accessed on 8/29/2015
  3. ↑ Disorders of Ocular Movement and Pupillary Function In: Adams and Victor's Principles of Neurology. 10th ed. Accessed on AccessMedicine.com on 8/29/2015. Chapter 14
  4. ↑ 4.0 4.1 4.2 4.3 4.4 Brazis, PW. Isolated palsies of cranial nerves III, IV, and VI. Seminars in neurology. 2009 Feb. 29(1):14
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