Cyclical oculomotor spasm, , Ocular neuromyotonia, Superior oblique myokymia

Question 1

Cyclincal ocular motor spasm characteristics

Answer 1

Rare non progressive oculomotor (III) palsy. The muscles innervated by III nerve undergo alternate rhythmic spasms and paralysis.

Question 2

Features

Answer 2

There are brief spasms of III nerve function which alternated between complete or partial III nerve palsy.
The cycle can consists of periods of ptosis and mydriasis alternating between lid retraction with miosis (Yazici, 2000). There are possible lesions in region of supraclinoid.

Question 3

2 phases

Answer 3

Paretic phase
Spastic phase

Question 4

Paretic phase

Answer 4

III nerve palsy - ptosis, dilated pupil (mydriasis), reduced accommodation, exotropia/hypotropia

Question 5

Spastic phase

Answer 5

Every 2-3 minutes – lasts 10-30 secs, Ptotic lid elevates, pupil constricts (miosis), esotropia

Question 6

Mydriasis

Answer 6

dilated pupil

Question 7

Miosis

Answer 7

constricted pupil

Question 8

Features

Answer 8

(A) Ocular motility during the paretic phase while the left affected eye is in mydriasis with lid ptosis.

(C) During the spastic phase, the pupil is in miosis, the lid retracts, and the affected left eye drifts upward and inward, but the paresis persists

Question 9

Treatment of COS

None

Answer 9

Medication-No effective treatment currently. If palsy persists they can consider surgery.

Question 10

Ocular neuromyotonia characteristics

no known cause

Answer 10

Transient spasms of EOM’s and it is induced in sustained gaze.
Intermittent diplopia and it can affect III, IV or VI cranial nerve.
Majority of patients have history of parasellar tumour and have undergone radiation therapy. There is no known cause.

Question 11

Treatment of ON

C medicine

Answer 11

Medical- carbamazepine 200mg reduces frequency of attacks

Question 12

Example; L oculomotor ocular neuromyotonia

Answer 12

PP- orthophoria
a). Following 30 s of right eccentric gaze
(b), the patient developed involuntary contraction of left medial rectus, which resulted in left esotropia while returning both eyes to the primary position
(c). The left esotropia lasted approximately 2 min,
(d)then spontaneously resolved

Question 13

Case reports- Ezra et al (1996). Ocular neuromyotonia

Answer 13

There are 3 patients- 2 patients have III nerve affected- 1 due to compression of ICAA, 1 due to radiotherapy for pituitary tumour, 3rd patient IV nerve affected induced by alcohol

Question 14

Case 1- 60 yr old male.

Referred with supraorbital pain; family members noticed RE appear to stare from time to time; episodes of intermittent diplopia
Partial R III nerve palsy with upper lid retraction on downgaze
Sustained elevation resulted in spasm of right levator with marked retraction of upper lid
Sustained adduction resulted in spasm of RMR with restriction of abduction and no change to lid
Imaging
MRI showed supraclinoid mass on right and MRI angiography showed aneurysm of ICA at at its junction with the posterior communicating artery, impinging on the roof of the cavernous sinus where the right third nerve enters the sinus

Treatment?

Answer 14

Carbamazepine 200mg twice daily gave resolution of the symptoms within 1 week but the partial third remained. Reduction of medication resulted in a return of symptoms

Question 15

Case 2
37 yr old female
c/o few months of ‘difficulty focussing’ especially when looked to the sides
No actual diplopia
Difficulty adjusting to altered light levels
General health
Acromegaly due to pituitary macroadenoma 11yrs prior to presentation
Trans-sphenoidal resection 1999
Radiotherapy 6 months later
Steretatic radiosurgery as residual tumour in right cavernous sinus
Persistently active acromegaly (a rare condition where the body produces too much growth hormone, causing body tissues and bones to grow more quickly.)
Investigation
VA 6/5 EE, Near exophoria, OM full, No proptosis or ptosis, No RAPD, 55” Frisby, Normal IOP, Clear media with healthy discs and maculae, Visual fields: Confrontation & Goldmann perimetry: normal
6 months later
Pt still aware of ‘funny things happen to my eyes’ Difficulty adjusting to light levels especially RE persisted. Boyfriend noticed right eye turning out but not for long
Investigation further
As before but Orthoptists thought possible hypometric saccades to the right.
OCT normal, MRI reviewed no recurrence of tumour / no abnormality of midbrain, pons or cerebellum, Nothing to explain symptoms
6 months later again
Things getting worse
Still difficulty adjusting to bright light especially RE
‘My right eye gets stuck to the side especially if looking quickly from one side to the other’. It can last 5 mins

Aetiology?

Answer 15

May present following head or ocular trauma or after brainstem tumour (rare)
Also been linked to neurovascular compression syndromes

Question 16

SO myokymia characteristics

its best observed on slit lamp

Answer 16

Fine rapid eye movements
Vertical and torsional eye movements.
Microtremor and intosion is seen

It can follow a SO palsy and the patient is aware of oscillopsia and diplopia and it can be triggered.
By fatigue, reading, stress and they occur spontaneously,

Question 17

Videos on SO myokymia

Answer 17

https://collections.lib.utah.edu/details?id=188456
https://www.youtube.com/watch?v=HwsJvCOC6_Q

Question 18

Treatment case 2

Answer 18

Medication- beta blockers, propranolol, levobunolol, - reduced symptoms in 2 patients with no side-effects (Zhang et al. 2018), carbamazepine
Surgery- SO tenectomy/ tenotomy, cause iatrogenic SO palsy and require ipsilateral IR recession, SO tenotomy & IO myectomy, partial weakening of SO tendon, BT injection (Superior oblique) – often affect other EOM’s as well
Symptoms can recur

Question 19

Case 3 - 53 yo female
History of episodes of twitching in RE
Observation
Rythmic down beating and intorting movements
Diagnosis
Superior Oblique Myokymia
Treatment
Carbamazepine 800mg daily reduced symptoms by 50% but unacceptable side effects
Over several years alternative drug therapies tried without success and resorted to wearing a patch most of the time
7 years later
She had surgery; excision of proximal portion of her right superior oblique tendon, the trochlea and 10mm of SO muscle.
Post-op:
fusion with 2∆ BD RE 2∆ BU LE and slight head tilt left.
Not requested surgery for iatrogenic palsy of her SO

Answer 19

SO and IO affected

Question 20

SO and IO affected

Answer 20

In one case there was an alternating SO myokymia followed by IO myokymia

Question 21

Summarising aetiologies

Answer 21

COS- muscles innervated by III nerve undergo alternate rhythmic spasms and paralysis
ON- no known cause
SOM- May present following head or ocular trauma or after brainstem tumour (rare)
Also been linked to neurovascular compression syndromes

Question 22

need to know

Answer 22

Cyclic oculomotor spasms
Ocular neuromyotonia
Superior oblique myokymia

Aetiology, findings, phases and management