Abducens Nerve Palsy and Esotropia
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Questions and Answers

Which nerve is responsible for controlling the lateral rectus muscle that abducts the eye?

  • Trochlear (fourth cranial) nerve
  • Abducens (sixth cranial) nerve (correct)
  • Oculomotor (third cranial) nerve
  • Trigeminal (fifth cranial) nerve

    • What is the most common ocular motor paralysis in adults?

  • Trochlear (fourth cranial) nerve palsy
  • Trigeminal (fifth cranial) nerve palsy
  • Abducens (sixth cranial) nerve palsy (correct)
  • Oculomotor (third cranial) nerve palsy

    • What is the result of an abducens nerve palsy?

  • Exotropia
  • Hyperopia
  • Esotropia (correct)
  • Myopia

    • Where does the abducens nerve travel through before entering the orbit?

    <p>Cavernous sinus and superior orbital fissure</p> Signup and view all the answers

    What is a risk factor for abducens nerve palsy in adults?

    <p>Hypertension</p> Signup and view all the answers

    What is the significance of a sudden onset of abducens nerve palsy?

    <p>It suggests a vascular etiology</p> Signup and view all the answers

    What is the anatomical location where the abducens nerve is tethered?

    <p>Dorello’s canal</p> Signup and view all the answers

    What is the location of the nucleus of the abducens nerve?

    <p>Pons</p> Signup and view all the answers

    What is the most common diagnostic procedure for abducens nerve palsy?

    <p>Magnetic Resonance Imaging (MRI) with gadolinium and fat suppression</p> Signup and view all the answers

    In which patients is MRI recommended?

    <p>All patients under the age of 50 years, those that present with non-isolated abducens nerve palsy, have a history of cancer, or have an absence of microvascular risk factors</p> Signup and view all the answers

    How is diplopia in myasthenia gravis characterized?

    <p>Fluctuating and fatigable</p> Signup and view all the answers

    What is the primary treatment for underlying or systemic conditions in abducens nerve palsy?

    <p>Treating the underlying condition</p> Signup and view all the answers

    How long do most patients with microvascular abducens nerve palsy recover?

    <p>3-6 months</p> Signup and view all the answers

    What is the purpose of botulinum toxin injections in abducens nerve palsy?

    <p>To weaken the medial rectus</p> Signup and view all the answers

    When is surgical intervention usually reserved for?

    <p>After 6 months of stable orthoptic measurements</p> Signup and view all the answers

    What is the most likely complication following surgical correction of abducens nerve palsy?

    <p>Over- or under-correction</p> Signup and view all the answers

    What determines the prognosis for abducens nerve palsy?

    <p>Underlying etiology</p> Signup and view all the answers

    What suggests a demyelinating process?

    <p>Subacute onset</p> Signup and view all the answers

    What is the most common presenting symptom of abducens nerve palsy?

    <p>Diplopia</p> Signup and view all the answers

    What is the cardinal sign of abducens nerve palsy?

    <p>Esotropia of the affected eye</p> Signup and view all the answers

    What is the location of the lesion in Millard-Gubler syndrome?

    <p>Brainstem</p> Signup and view all the answers

    What is the purpose of cycloplegic refraction in the evaluation of abducens nerve palsy?

    <p>To assess the refractive error of the patient</p> Signup and view all the answers

    Why is it important to test each eye independently in the evaluation of abducens nerve palsy?

    <p>To avoid pseudo-restrictive effects of alternating monocular fixation and vergence</p> Signup and view all the answers

    What is the characteristic of esotropia in abducens nerve palsy?

    <p>It is incomitant and greater at distance</p> Signup and view all the answers

    What is the usual method of diagnosis of abducens nerve palsy?

    <p>Clinical examination</p> Signup and view all the answers

    What is the characteristic of diplopia in abducens nerve palsy?

    <p>Horizontal and uncrossed</p> Signup and view all the answers

    What is the significance of slow saccadic velocity in side gaze?

    <p>It is a diagnostic feature of abducens nerve palsy</p> Signup and view all the answers

    What is the primary reason why the affected eye turns medially in abducens nerve palsy?

    <p>Due to the unopposed action of the medial rectus muscle</p> Signup and view all the answers

    Where does the abducens nerve begin its course?

    <p>In the dorsal pons</p> Signup and view all the answers

    What is the significance of a slowly progressive onset of abducens nerve palsy?

    <p>It suggests a compressive etiology</p> Signup and view all the answers

    What is the characteristic of esotropia in abducens nerve palsy?

    <p>It is incomitant and greater at near than at distance</p> Signup and view all the answers

    What is the anatomic location where the abducens nerve is tethered?

    <p>In Dorello's canal</p> Signup and view all the answers

    What is the most common presenting symptom of abducens nerve palsy in children?

    <p>Diplopia</p> Signup and view all the answers

    What is the risk factor for abducens nerve palsy in adults?

    <p>All of the above</p> Signup and view all the answers

    What is the characteristic of the abducens nerve course?

    <p>It has the longest intracranial course</p> Signup and view all the answers

    What is the most common underlying etiology of abducens nerve palsy in children?

    <p>Neoplasm</p> Signup and view all the answers

    What is the significance of palpebral fissure widening upon abduction effort in abducens nerve palsy?

    <p>It is a sign of attempted abduction</p> Signup and view all the answers

    What is the characteristic of esotropia in abducens nerve palsy?

    <p>It is greater at distance than at near</p> Signup and view all the answers

    What is the significance of slow saccadic velocity in side gaze in abducens nerve palsy?

    <p>It is a diagnostic feature of abducens nerve palsy</p> Signup and view all the answers

    What is the purpose of measuring fusional amplitudes in the evaluation of abducens nerve palsy?

    <p>To assess the quality of binocular vision</p> Signup and view all the answers

    What is the characteristic of diplopia in abducens nerve palsy?

    <p>It is horizontal and uncrossed</p> Signup and view all the answers

    What is the significance of a head turn toward the affected eye in abducens nerve palsy?

    <p>It is a compensatory mechanism to avoid diplopia</p> Signup and view all the answers

    What is the significance of raised intracranial pressure in abducens nerve palsy?

    <p>It is a symptom of headache and pain around the eyes</p> Signup and view all the answers

    What is the characteristic of the deviation in abducens nerve palsy?

    <p>It is greater at distance than at near</p> Signup and view all the answers

    What is the importance of evaluating ductions and versions in the diagnosis of abducens nerve palsy?

    <p>It is helpful in determining incomitance</p> Signup and view all the answers

    What is the primary purpose of MRI in the diagnosis of abducens nerve palsy?

    <p>To rule out underlying etiologies</p> Signup and view all the answers

    Which of the following conditions may present with unilateral symptoms including proptosis and inflammation?

    <p>Thyroid eye disease</p> Signup and view all the answers

    What is the significance of a 6-month period in the management of abducens nerve palsy?

    <p>The time required for orthoptic measurements to stabilize</p> Signup and view all the answers

    What is the purpose of forced duction test in the management of abducens nerve palsy?

    <p>To assist with surgical planning</p> Signup and view all the answers

    What is the most common complication following surgical correction of abducens nerve palsy?

    <p>Over- or under-correction</p> Signup and view all the answers

    What is the significance of the presence of microvascular risk factors in patients with abducens nerve palsy?

    <p>It may affect the decision to perform MRI</p> Signup and view all the answers

    What is the purpose of occlusion using a Bangerter filter or patch in the management of abducens nerve palsy?

    <p>To eliminate diplopia and confusion</p> Signup and view all the answers

    What is the characteristic of diplopia in patients with myasthenia gravis?

    <p>It is fluctuating and fatigable</p> Signup and view all the answers

    In which patients may the diagnostic yield of MRI be relatively low?

    <p>Elderly patients with isolated abducens nerve palsy and vasculopathic risk factors</p> Signup and view all the answers

    What is the primary goal of treatment for underlying or systemic conditions in patients with abducens nerve palsy?

    <p>To treat the underlying condition</p> Signup and view all the answers

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