Myogenic Palsies
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Questions and Answers

What is the primary cause of Thyroid Eye Disease?

  • Autoimmune inflammatory disease (correct)
  • Environmental factors
  • Bacterial infection
  • Viral infection

    • The dry phase of Thyroid Eye Disease is a self-limiting phase that usually resolves on its own within 3 years.

    False

    What is the term for the excessive opening or swelling of the eyelids in Thyroid Eye Disease?

    retraction

    During the wet phase of Thyroid Eye Disease, the extraocular muscles become like ______________ and swell up.

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

    Match the stages of Thyroid Eye Disease with their characteristics:

    <p>Wet phase = Active inflammatory process resulting in cellular infiltrates and increased water content Dry phase = Fibrotic phase – the stage in which the muscles become stiff</p> Signup and view all the answers

    What surgery may be required to treat severe protrusion of the eye in Thyroid Eye Disease?

    <p>Orbital decompression surgery</p> Signup and view all the answers

    What is the typical order of limitation in an eye?

    <p>IR-MR-SR-LR</p> Signup and view all the answers

    Diplopia is worse in the evening due to the fluid gathering in the ocular tissues.

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

    What is the primary usage of the programming language, JavaScript?

    <p>Not applicable</p> Signup and view all the answers

    Parinaud's syndrome is a supranuclear disorder caused due to the compression of the vertical gaze centre at the _______________________

    <p>rostral interstitial nucleus of the medial longitudinal fasciculus</p> Signup and view all the answers

    What is the main limitation in an eye?

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

    Werner's classification is a grading system for thyroid eye disease.

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

    What is the purpose of tinted specs in the management of thyroid eye disease?

    <p>To help the cosmetic point of view</p> Signup and view all the answers

    The clinical feature of Parinaud's syndrome includes _______________________

    <p>light/near dissociation</p> Signup and view all the answers

    Match the following signs of thyroid eye disease with their descriptions:

    <p>Upper lid retraction = Lid lag Staring appearance = Creepy Chemosis = Oedema and injection of conjunctiva Tremor on gentle lid closure = Raised IOP on elevation</p> Signup and view all the answers

    What is the most common type of myogenic palsy?

    <p>Myasthenia Gravis</p> Signup and view all the answers

    In Myasthenia Gravis, the weakness of the ocular muscle is due to a primary problem affecting the nerve supply.

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

    What is the main characteristic of Myasthenia Gravis?

    <p>Excessive fatigability of the voluntary striated muscles</p> Signup and view all the answers

    The formation of _______________ antibodies prevents acetylcholine receptors from binding and reduces the effectiveness of the neurotransmitter.

    <p>acetylcholine receptor</p> Signup and view all the answers

    Match the following symptoms with the correct diagnosis:

    <p>Diplopia = Myasthenia Gravis Ptosis = Myasthenia Gravis Lid lag = Thyroid Eye Disease Reduced IOP = Diabetic Retinopathy</p> Signup and view all the answers

    In Myasthenia Gravis, the general symptoms get better as the day goes on.

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

    What is the purpose of the Ice pack test in Myasthenia Gravis?

    <p>To improve symptoms and ptosis by lowering the temperature</p> Signup and view all the answers

    What is the purpose of the Sleep test in Myasthenia Gravis?

    <p>To observe lid position improvement after 30 minutes of sleep</p> Signup and view all the answers

    The Tensilon test involves the injection of _______________ intravenously.

    <p>edrophonium (short acting anticholinesterase)</p> Signup and view all the answers

    In Myasthenia Gravis, the EOMs are affected last.

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

    What is the typical order of limitation in an eye?

    <p>IR-MR-SR-LR</p> Signup and view all the answers

    In Parinaud's syndrome, the vertical gaze centre is compressed at the lateral longitudinal fasciculus.

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

    What is the purpose of lubricating eye drops in the management of thyroid eye disease?

    <p>To help with grittiness and pain</p> Signup and view all the answers

    In Parinaud's syndrome, the pupils are usually _______________________ and react only to accommodation.

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

    Match the following signs of thyroid eye disease with their descriptions:

    <p>Chemosis = Oedema and injection of conjunctiva Lid lag = Upper lid retraction Convergence insufficiency = Inability to hold fixation on extreme lateral gaze Diplopia = Double vision</p> Signup and view all the answers

    What is Werner's classification used for?

    <p>To grade the severity of thyroid eye disease</p> Signup and view all the answers

    Diplopia is worse in the evening due to fluid gathering in the ocular tissues.

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

    What is the purpose of Bells phenomenon in the management of thyroid eye disease?

    <p>To prevent keratitis</p> Signup and view all the answers

    In thyroid eye disease, the extraocular muscles become swollen and _______________________ like.

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

    What is the purpose of medical treatment with oral steroids in thyroid eye disease?

    <p>To treat severe swelling and pain</p> Signup and view all the answers

    What is the result of the autoimmune system attacking the thyroid in Thyroid Eye Disease?

    <p>Too much thyroxin is produced</p> Signup and view all the answers

    The dry phase of Thyroid Eye Disease is a chronic phase where the EOMs are strangled and degenerated.

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

    What is the consequence of the swelling of the EOMs in the wet phase of Thyroid Eye Disease?

    <p>compression and vision loss</p> Signup and view all the answers

    During the wet phase of Thyroid Eye Disease, the extraocular muscles become like ___________ and swell up.

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

    Match the following characteristics with the stages of Thyroid Eye Disease:

    <p>Wet Phase = Active inflammatory process resulting in cellular infiltrates and increased water content Dry Phase = Fibrotic phase where the muscles become stiff</p> Signup and view all the answers

    What is the characteristic of Myasthenia Gravis that affects the voluntary striated muscles?

    <p>Early muscle fatigue</p> Signup and view all the answers

    In Myasthenia Gravis, the B cells block acetylcholine receptors, leading to increased muscle contraction.

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

    What is the significance of Cogan's sign in Myasthenia Gravis?

    <p>A twitch can be seen in the upper lid as it overshoots the midline and then returns to its ptotic position.</p> Signup and view all the answers

    The primary usage of the ophthalmic test, exophthalmometry, is to measure _______________________.

    <p>the degree of proptosis</p> Signup and view all the answers

    Match the following ophthalmic tests with their purposes:

    <p>IOP = measuring intraocular pressure Hess chart = plotting the outer fields of binocular vision Forced duction test = proving tethering of the extraocular muscles CT/MRI = confirming Thyroid Eye Disease by showing thickened extrinsic muscles</p> Signup and view all the answers

    In Thyroid Eye Disease, the limited elevation of the globe is the most common limitation.

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

    What is the significance of the field of binocular single vision in Thyroid Eye Disease?

    <p>It is frequently much larger than the extent of limitation seen on the Hess chart.</p> Signup and view all the answers

    What is the purpose of the Tensilon test in Myasthenia Gravis?

    <p>to diagnose Myasthenia Gravis by injecting edrophonium intravenously</p> Signup and view all the answers

    In Myasthenia Gravis, the EOMs have a high concentration of _______________________.

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

    In Myasthenia Gravis, the general symptoms improve as the day goes on.

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

    Study Notes

    Graves' Orbitopathy (TED)

    • Autoimmune inflammatory disease of the orbit and periorbital tissue
    • Autoimmune system attacks the thyroid, leading to excessive thyroxin production (too much T3 and T4)
    • Two stages: Wet phase (Active) and Dry phase (Inactive)
    • Wet phase: active inflammatory process, cellular infiltrates, increased water content, and swelling of EOMs
      • Can cause compression and vision loss
      • More likely to occur in those without proptosis
      • Self-limiting, typically lasts 3 years
    • Dry phase: fibrotic phase, muscles become stiff and degenerated
      • Chronic subacute phase, EOMs are strangled and cannot contract
      • Causes tethering, fibrosis, and scarring
      • Residual problems usually managed with surgery

    Clinical Signs and Symptoms

    • Insidious onset of diplopia
    • Upper lid retraction
    • Lid lag
    • Reduced frequency of blinking
    • Weak convergence
    • Inability to hold fixation on extreme lateral gaze
    • Staring appearance
    • Chemosis
    • Oedema and injection of conjunctiva
    • Tremor on gentle lid closure
    • Raised IOP on elevation/attempted elevation
    • Reduced colour vision
    • Diplopia associated with some degree of external ophthalmoplegia
    • Diplopia worse in the morning due to fluid accumulation in ocular tissues
    • Pain on eye movement due to fibrosed muscles
    • Epiphora
    • Grittiness of eye
    • General discomfort
    • Photophobia
    • AHP of chin elevation
    • Visual loss in extreme cases (optic compression)
    • Reduced field of binocular single vision

    Werners' Classification

    • N: no physical symptoms or signs
    • O: ocular irritation
    • S: soft tissue involvement (periorbital swelling, lid lag, etc.)
    • P: proptosis (axial, 80% bilateral)
    • E: EOM involvement
    • C: corneal involvement (congestion of episcleral vessels, chemosis, dilated vessels)
    • S: optic neuropathy, papilloedema, sight loss

    Management

    • Tinted specs for cosmetic purposes
    • Regular refraction for frequent astigmatism changes
    • Bells' phenomenon (if lost, lids must be taped at night to prevent keratitis)
    • Mechanical deviation (reversal of diplopia with prisms)
    • Lubricating eye drops for grittiness and pain
    • Medical treatment with oral steroids for severe swelling and pain
    • Surgery for severe proptosis, orbital decompression, and squint surgery

    Parinaud's Syndrome (Dorsal Midbrain Syndrome)

    • Supranuclear disorder caused by compression of the vertical gaze centre
    • Clinical features:
      • Loss of upward saccadic eye movement
      • Light/near dissociation
      • Colliers' sign (bilateral or upper eyelid retraction with lid lag)
      • Convergence insufficiency
      • Accommodative insufficiency
      • Skew deviation
      • Convergence retraction nystagmus
      • Pupils are dilated with a reduction in light response

    Myasthenia Gravis (MG)

    • Rare chronic autoimmune disease
    • Characterized by excessive fatigability of voluntary striated muscles
    • Most commonly affects EOMs but may progress to generalised muscle involvement
    • Formation of acetylcholine receptor antibodies
    • Clinical features:
      • Diplopia (vertical, horizontal, or both)
      • Ptosis (usually first sign, bilateral but asymmetrical)
      • Lid closure (patient can always close eyelids)
      • Lid flutter (fine fluttering of lid margins)
      • Lid twitch (Cogan's sign)
      • Defects in articulation, phonation, breathing, and facial expression
      • Symptoms worsen as the day progresses

    Assessment of Ptosis

    • Ptosis increases on continued elevation or repeated up and down gaze
    • +ve Cogan's lid twitch (px looks down for 15 seconds, then refixates in PP)

    Investigation of MG

    • Ice pack test
    • Sleep test
    • Blood test for acetylcholine receptor antibodies
    • EMG
    • Tensilon test (edrophonium injection)

    Management of MG

    • Fresnel prisms
    • Ptosis props
    • Occlusion to reduce diplopia
    • Botox to improve ptosis/strabismus surgery
    • Immunosuppression with systemic steroids (10mg prednisolone)
    • Azathiprine or myophenolate can enhance steroids
    • Avoid triggers of symptoms (tiredness and stress)

    Graves' Orbitopathy (TED)

    • Autoimmune inflammatory disease of the orbit and periorbital tissue
    • Autoimmune system attacks the thyroid, leading to excessive thyroxin production (too much T3 and T4)
    • Two stages: Wet phase (Active) and Dry phase (Inactive)
    • Wet phase: active inflammatory process, cellular infiltrates, increased water content, and swelling of EOMs
      • Can cause compression and vision loss
      • More likely to occur in those without proptosis
      • Self-limiting, typically lasts 3 years
    • Dry phase: fibrotic phase, muscles become stiff and degenerated
      • Chronic subacute phase, EOMs are strangled and cannot contract
      • Causes tethering, fibrosis, and scarring
      • Residual problems usually managed with surgery

    Clinical Signs and Symptoms

    • Insidious onset of diplopia
    • Upper lid retraction
    • Lid lag
    • Reduced frequency of blinking
    • Weak convergence
    • Inability to hold fixation on extreme lateral gaze
    • Staring appearance
    • Chemosis
    • Oedema and injection of conjunctiva
    • Tremor on gentle lid closure
    • Raised IOP on elevation/attempted elevation
    • Reduced colour vision
    • Diplopia associated with some degree of external ophthalmoplegia
    • Diplopia worse in the morning due to fluid accumulation in ocular tissues
    • Pain on eye movement due to fibrosed muscles
    • Epiphora
    • Grittiness of eye
    • General discomfort
    • Photophobia
    • AHP of chin elevation
    • Visual loss in extreme cases (optic compression)
    • Reduced field of binocular single vision

    Werners' Classification

    • N: no physical symptoms or signs
    • O: ocular irritation
    • S: soft tissue involvement (periorbital swelling, lid lag, etc.)
    • P: proptosis (axial, 80% bilateral)
    • E: EOM involvement
    • C: corneal involvement (congestion of episcleral vessels, chemosis, dilated vessels)
    • S: optic neuropathy, papilloedema, sight loss

    Management

    • Tinted specs for cosmetic purposes
    • Regular refraction for frequent astigmatism changes
    • Bells' phenomenon (if lost, lids must be taped at night to prevent keratitis)
    • Mechanical deviation (reversal of diplopia with prisms)
    • Lubricating eye drops for grittiness and pain
    • Medical treatment with oral steroids for severe swelling and pain
    • Surgery for severe proptosis, orbital decompression, and squint surgery

    Parinaud's Syndrome (Dorsal Midbrain Syndrome)

    • Supranuclear disorder caused by compression of the vertical gaze centre
    • Clinical features:
      • Loss of upward saccadic eye movement
      • Light/near dissociation
      • Colliers' sign (bilateral or upper eyelid retraction with lid lag)
      • Convergence insufficiency
      • Accommodative insufficiency
      • Skew deviation
      • Convergence retraction nystagmus
      • Pupils are dilated with a reduction in light response

    Myasthenia Gravis (MG)

    • Rare chronic autoimmune disease
    • Characterized by excessive fatigability of voluntary striated muscles
    • Most commonly affects EOMs but may progress to generalised muscle involvement
    • Formation of acetylcholine receptor antibodies
    • Clinical features:
      • Diplopia (vertical, horizontal, or both)
      • Ptosis (usually first sign, bilateral but asymmetrical)
      • Lid closure (patient can always close eyelids)
      • Lid flutter (fine fluttering of lid margins)
      • Lid twitch (Cogan's sign)
      • Defects in articulation, phonation, breathing, and facial expression
      • Symptoms worsen as the day progresses

    Assessment of Ptosis

    • Ptosis increases on continued elevation or repeated up and down gaze
    • +ve Cogan's lid twitch (px looks down for 15 seconds, then refixates in PP)

    Investigation of MG

    • Ice pack test
    • Sleep test
    • Blood test for acetylcholine receptor antibodies
    • EMG
    • Tensilon test (edrophonium injection)

    Management of MG

    • Fresnel prisms
    • Ptosis props
    • Occlusion to reduce diplopia
    • Botox to improve ptosis/strabismus surgery
    • Immunosuppression with systemic steroids (10mg prednisolone)
    • Azathiprine or myophenolate can enhance steroids
    • Avoid triggers of symptoms (tiredness and stress)

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    Description

    This quiz covers the clinical signs and stages of Graves' Orbitopathy, an autoimmune inflammatory disease affecting the orbit and periorbital tissue, including eyelid retraction, proptosis, EOM involvement, and optic neuropathy.

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