Revison for exam short note questions Flashcards
(13 cards)
Parinauds Syndrome
Loss of upward saccadic movement with normal vertical pursuit.
Very uncommon but when present mainly in children than adults.
Lesion in upper mid brain and is caused by a tumour or cyst on the pinel gland.
Px will have covergance retraction nystagmus, this will best be seen on downwards roatational movements.
Px will have light / near dissociation- meaning they will have usually dilated pupils that will only react to accomodation and not to light.
Aetiology of parinauds includes- Pineal gland tumours, Stroke, and assocaited hydrocephalus due to increased ICP.
Other signs of the disease include:-
1. Colliers signs which is Bilateral upper eyelid retraction with a Lid Lag
2. Papilloedema can be seen in children espically of they have hydrocephalus, can also be seen in adults.
3. Convergence insufficiency
4. accomodation insuffiency
5. skew devition
6. progressive lesion, INO and 3rd, 4th and 5th nerve palsies
Inteanuclear Opthalmoplegia (INO)
Is a lesion of the medial longtitudual fasciculus (MLF) adn will result in the pasly of the medial rectus muscle, and will also cause dissociated gaze evoked nystagmus of the abducting eye (ataxia nystagmus), this is due to increased innervation convergence. this however can remain unaffected if the lesion in question is small.
In INO there is no dammage to the MLF therefore causing a adduction defect, convergence in most cases is still intact.
Has two types unilateral and Bilateral
Unilateral:-
- Affects the internerurons of only 1 6th nerve nucleus.
- Saccadic, pursuit and VOR movements are all affected
- Milder cases may only show a reduction in peak saccadic velocity of the affected medial rectus.
- Abducting nystagmus will then be seen in the unaffected eye.
- If lesion is located in the lower MLF then convergence may remain intact.
- If convergence and adduction are both affected then lesion is likely to be higher in the MLF, this will be closer to the third nerve nucleus.
- Skew deviations may also be seen in unilateral INO & the hypertropic eye is on the same side as the INO.
Bilateral:-
- Larger lesions that affect the eye interneurons rinning in both MLF
- Bilateral addustiob loss with Bilateral ataxia nystagmus of the abducting eye
- PX may be assymptomatic, and convergence may still be intact
- Px will present wiyh Upbeat nystagmus and Vertical gaze defects
- WEBINO - wall eyed bilateral internuclear opthalmoplegia
- Large angled exotropia if the patient has a previous EXO deviation
- Common in neurological disorders
Aetiology includes; MS, Stroke- Bilateral artery occlusion and tumours (Rare).
Persenting signs:-
- EOP/EOT on cover test
- Will increase on attempted adduction
- Impaired/slow saccades are useful when differenciating a clionical INO from an assymetrical Bilateral INO
- Ataxia nystagmus on lateral gaze
Ataxia nystagmus:-
- this is thoght to be due to addaptive changes to the MR
- Central changes cause an increased innervation to the affected MR plus equal to excessive innervation to the contralateral MR
- Will cause an initial overshoot and then drift back to the target.
Duanes retraction syndrome
Classed as a mechanical disease that causes congenital developmental errors in innervation.
Is described by Brown to have 3 classifications:-
type 1- limited abduction and adduction
type 2- limited abduction
type 3- limited adduction and abduction
Tyyical ocular motility findings of pxs suffering from this include:-
- Limitations of right abduction
- Overreaction of contralateral MR (Synergist)
- Globe reataction on adduction
- Narrowing of palpebral fissure on adduction and widening on adduction
Aetiology;-
- Innervation of the lateral rectus by extra branches of the 3rd Nerve instead of absent or deficient 6th nerve fibers
- autopsy will show an absent 6th nerve and nucleus and as a result the inferior division of the 3rd nerve will supply the Lateral rectus
- will also be other nerve deficiencies present
Ocular features include:-
- Limited horizontal motility
- Unilateral or Bilateral
- AHP- face turn to affected side
- Mostly esodeviations and usually a esophoria
- Normal Binocular single vision
- up/down shoots on adduction
- A + V patterns
- Globe retraction on adduction and therefore narrowing of palpebral apperture
- Widening of palpebral fissure on attempted abduction
- Diplopia is very rare and only present in the absenct of binocular single vision.
Management:-
- Refer to HES
- No treatment often due to BSV, small degree of suppression, CHP
- Amblyopia therapy if required
- Surgeryvscscdscc
Browns syndrome
Is a limitation of elevation in adduction and will cause a down drift of the effected eye on contralateral versions.
Is a over action of the Contralateral superior rectus and will have an A or V pattern.
Px will have discomfort on attempted elevation on adductuion and also have a positive forced duction test result.
Cover test results:-
- with mechanical deviations such as browns syndrome you will find a small vertical deviation in primary position.
- E.g. ocular motility in RE browns = -3 in Re and a +3 in LE.
Aetiology in acquired Browns syndrome includes:-
- tendon sheath abnormalities
- Tendon abnormalities
- Trauma / inflammatory arthritis
- Differential diagnosis- congenital inflammatory oblique palsy
Aetiology in congenital is uncomfirmed but is potentially linked to paradoxcical innervation of the superior oblique and also structural abnormalities of the inferior oblique.
Incidence includes:-
- Unilateral right affected as much as left
- thought to develop in infancy, very few are congenital.
- Can be acquired later from inflammation to trauma or trochlear
- Males are affected as much as females
- Studies have found that patients may spontaneously recover over a peroid of time.
Management:-
- If the patient has BSV in primary position is left alone
- Surgical innervation only if the patient decomoensates in the primary position, acquired cases may require that the underlying aetiology is treated.
- Conservative aproach to treatment is obervation and corticosteroids.
- Surgical innervation includes tonometry and tenectomy of superior oblique and also split tendon lenghtening.
Blow out fracture
Can be caused by orbital traumas such as fist, elbows in rugby and hocky balls
mechansim = Force of blow -> backward displacement of eyeball -> raised intraocular pressure -> raised IOP -> fracture of the weakest part of the orbital wall.
Clinical findings accociated with an orbital blowout fracture may include:-
- Endopthalmitis
- Orbital emphysema
- macular region numbness
- Hypoglobus
Inferior blowout fracture:-
- Most common
- Orbital flap prolapse into macillary sinus and may be joined vis prolapse of inferior rectus muscle
- Most fractures occur in the floor of the orbit in the posterior and medial infraorbital position
- 50% of these fractures are joined with a medial wall fracture.
Medial blowout fracture:-
- second most common and occurs through the lamina papracea
- Orbital fat and medial rectus muscle may prolaplse into the ethmoid air cells.
Superior blowout fracture:-
- uncommon and usually seen in PX with pneumatisation of the orbital roof
- any communication seen with anterior carania fossa are at a risk of CSF leak and therefore meningitis.
Lateral blowout fracture:-
- rare as the bone is thick and bounded by muscle.
- Fractures that are presrent are usually associated with the orbital rim or other significant caraniofacial injuires.
Clinical examinations include:-
- Visions
- cover test
- Motility
- Fusion
- Colour vision
- Ocular examination
- Fields
indications that surgery is needed:-
- Sig endopthalmitis
- Sig Diplopia
- Muscle entrapment with trapdoor in children
- large area of fracture.
CPEO
Is chronic progressive external Opthalmoplegia and is a myogenic condition
Features include:-
- Progressive, symetrical loss of motility
- Proceeded by progressive ptosis
- Orbicularis weakness
- Eyes become virtually immobile
- Fibrotic changes may occur later
- Pupillary reaction and accomodation unaffected
- Saccadic velocities always reduced
- Due to slow nature of progressive often no diploia.
Typical onset in early 20s and px will have normal eye movements durring childhood. sapordic eye movements occur due to autosomal dominant condition?
Aetiology:-
- mitochondrial disorder where there is a deletion of the mitochondrial DNA (mtDNA)
- the EOM are affected by this as they have a lower mutational threshold.
- CPEO can deelop in isolation or can develop alongside / is accosiated with a variaty of systemic disorders
- kearns square syndrome = this is a large scale single deletion of the mitochondrial DNA and can cause other conditions such as CPEO, fine pigmentary retinopathy and Heart conduction problems.
CPEO+ :-
- Reinitis pigmentosa
- Cardiac defects
- Deafness
- Cerebellar ataxia
- Peripheral neuropathies
- Mental retardation
- Endocryine disfunction
Management - No cure:-
- intake o f CoEnzyme Q10 through diatery supplimentation to increase mitocondrial production and therefore mitocondrial fundtion
- Gene therpy can also be used but there has been no one trated with this as of yet
BHHT and parks 3 step
BHHT:-
- performed at 3m
- Head tiltefd to the affected side by 30 deg and if the hypermetripia increases then a superior oblique pasly is present
- Head tilted to the unaffected side will show a very little difference in the deviation suggesting a contralateral superior rectus
- Positive result should be minimum 5^ difference from tilting right ot left
Parks 3 step:-
- Cover test will be performed in the primary position
- alternate cover test will be performed in dextroversion and laevoversion to assess the greater vertical deviations
- BHHT is hen perfoemed at 30 deg both right and left and the increasing hyperdeviation is noted down.
Ocular myosites
Sub grouo of idiopathic orbital inflammatory syndrome and involves 1 or more EOM
Effects twice as many females as it does males and can be both unilateral or bilateral
Majority present between the ages of 18-40 years and can be both chrinic or acute following a respiratory tract infection. Is commonlt reposted post strabismus surgery.
Features include:-
- Painful Diplopa = Horozontal is always affected more than vertical, pain will always worsen on eye movement
- If only 1 EOM involved = paratic in direction of muscle action, mechanical in other direction due to inflamatorey musclew affecting muscle relaxation.
- Orbital image shows swollen muscles
- Proptosis
- ptosis
- peri ocular redness and swelling.
Differential disgnosis includes; Idiopathic orbital inflammatory syndrome, orbital cellulitis, orbital rhabdomyosarcomas
Management:-
- self limiting = 4-8 weeks, responds well to cortical steroids
- made comfertable with prism whilst waiting for recovery
- occlusion
- if persistant motility problem - consider treatment such as BOTOXA, surgery is only done stable and when px off treatment (risk of further attacks)
Herings and Sherringtons law
Hering’s Law and Sherrington’s Law are both key principles in ocular motility—how the eyes move. They’re super important when understanding how the muscles of the eyes work together to maintain proper binocular vision.
Sherringtons law:-
- This law explains how muscles within the same eye work
- It states: When a muscle contracts, its direct antagonist relaxes to an equall extent.
- A good way to think about this is that one muscle pulls and the other muscle lets go.
Herings law:-
- This law explains how muscles in both eyes work together.
- It states: equal and simulatenous innervation is sent to yoked muscles in both eyes.
- i.e both eyes move to the right as a team as this helps maintain binocular vision.
Abberant regeneration
Definition:
Miswiring of regenerating cranial nerve fibers after injury → abnormal synkinesis.
Most Common Nerve:
CN III (Oculomotor)
(Often after trauma, aneurysm; not typical in ischemia)
Classic Signs:
- Pseudo-Graefe sign: Lid elevates on downgaze
- Lid-gaze dyskinesis: Lid moves with eye movements
- Pupil-gaze dyskinesis: Pupil constricts with eye movement
Key Point:
Suggests prior compressive lesion (e.g., aneurysm), not microvascular cause.
Classed as a mechanical disease that causes congenital developmental errors in innervation.
Is described by Brown to have 3 classifications:-
type 1- limited abduction and adduction
type 2- limited abduction
type 3- limited adduction and abduction
Tyyical ocular motility findings of pxs suffering from this include:-
- Limitations of right abduction
- Overreaction of contralateral MR (Synergist)
- Globe reataction on adduction
- Narrowing of palpebral fissure on adduction and widening on adduction
Aetiology;-
- Innervation of the lateral rectus by extra branches of the 3rd Nerve instead of absent or deficient 6th nerve fibers
- autopsy will show an absent 6th nerve and nucleus and as a result the inferior division of the 3rd nerve will supply the Lateral rectus
- will also be other nerve deficiencies present
Ocular features include:-
- Limited horizontal motility
- Unilateral or Bilateral
- AHP- face turn to affected side
- Mostly esodeviations and usually a esophoria
- Normal Binocular single vision
- up/down shoots on adduction
- A + V patterns
- Globe retraction on adduction and therefore narrowing of palpebral apperture
- Widening of palpebral fissure on attempted abduction
- Diplopia is very rare and only present in the absenct of binocular single vision.
Management:-
- Refer to HES
- No treatment often due to BSV, small degree of suppression, CHP
- Amblyopia therapy if required
- Surgeryvscscdscc
Duanes retraction syndrome
BHHT:-
- performed at 3m
- Head tiltefd to the affected side by 30 deg and if the hypermetripia increases then a superior oblique pasly is present
- Head tilted to the unaffected side will show a very little difference in the deviation suggesting a contralateral superior rectus
- Positive result should be minimum 5^ difference from tilting right ot left
Parks 3 step:-
- Cover test will be performed in the primary position
- alternate cover test will be performed in dextroversion and laevoversion to assess the greater vertical deviations
- BHHT is hen perfoemed at 30 deg both right and left and the increasing hyperdeviation is noted down.
BHHT and parks 3 step
Hering’s Law and Sherrington’s Law are both key principles in ocular motility—how the eyes move. They’re super important when understanding how the muscles of the eyes work together to maintain proper binocular vision.
Sherringtons law:-
- This law explains how muscles within the same eye work
- It states: When a muscle contracts, its direct antagonist relaxes to an equall extent.
- A good way to think about this is that one muscle pulls and the other muscle lets go.
Herings law:-
- This law explains how muscles in both eyes work together.
- It states: equal and simulatenous innervation is sent to yoked muscles in both eyes.
- i.e both eyes move to the right as a team as this helps maintain binocular vision.
Herings and Sherringtons law
