CPEO AND MYOSITIS Flashcards
Neurogenic palsies
Supranuclear, nuclear, internuclear & infranuclear
Mechanical
- Duanes/ browns
- Adherence syndrome
- TED
- Orbital injuries
- Orbital tumours
Myogenic
What is myogenic
- A primary disease of the muscle causing it to underact
The disease happens in the muscle
Myasthenia gravis
CPEO
Orbital/ Ocular myositis/ pseudo-tumour
Chronic Progressive External Ophthalmoplegia features
- Progressive, symmetrical loss of motility (up-gaze usually lost 1st)- not noticable by px, gradual onset
- Progressive ptosis usually preceding motility loss – complete ptosis at end
- Orbicularis weakness - eyes don’t close properly - corneal exposure
- Eyes become virtually immobile
- Fibrotic changes may occur later - muscle shrivels up
- Pupil reactions and accommodation unaffected (smooth muscle) - use for DIFFERENTIAL DIAGNOSIS
- Saccadic velocities always reduced -start off okay but BUT MG slow from beginning
- Due to slow nature of progression – often no diplopia
ALL EOM ARE AFFECTED IN OM with bilateral ptosis
Cant blink due to orbicularis weakness
No elevation, slight depression
Onset of CPEO
Age of onset
* Early 20’s – infancy to 68 reported * Normal eye movements during childhood
Sporadic genetic influence
* Autosomal dominant form does occur
Aetiology of CPEO
- Mitochondrial disorder – ATP energy producers
- Mitochondrial DNA (mtDNA) acquired
- Deletions of mtDNA
- mtDNA maternally transmitted – nearly all cases
Why EOM? > lower mutational threshold in EOM
Kearns-Sayre Syndrome
Large-scale single deletions of mitochondrial DNA
- CPEO in childhood – onset before 20 yrs
- Fine pigmentary retinopathy
- Heart conduction block
associated condition with CPEO
- Retinitis pigmentosa
- Cardiac defects
- Deafness
- Cerebellar ataxia
- Peripheral neuropathy
- Mental retardation
- Endocrine dysfunction
Higher levels of deleted mtDNA in a wider range of tissue
causes of CPEO
- Onset
- Natural history
- Saccade velocities
- CT / MRI – atrophic muscles
- Muscle biopsy – (skeletal muscle / eye muscle)
- Genetic testing for mtDNA deletions, histology for ‘ragged red fibres’
- Myasthenia - +ve Tensilon, antiacetylcholine receptor antibodies, normal saccadic velocities
- Mechanical disorders (Graves’ orbitopathy) – characteristic ocular features of Graves’ orbitopathy
- Congenital fibrosis of extra ocular muscles (CFEOM) – stationary, present at birth
- Supranuclear gaze palsy – improvement in movement on doll’s head testing, CPEO will remain unchanged
- Multiple cranial nerve palsies – depends on cranial nerves involved, brainstem demyelination has other neurological signs and symptoms
CPEO management
No cure - as it is a part of DNA
- Coenzyme Q10 – part of energy producing mechanism of mitochondria
- Dietary supplementation increases mitochondrial CoQ10 & mitochondrial function
- Control trials not yet carried out
- Gene therapy
- No cases treated with this yet
- Gene therapy is being tried for other mitochondrial disorders
signs and symptoms of CPEO
ECG and fundus examination (rule out Kearns Sayre syndrome)
* Can record progression of disease
* Limited value of Hess chart as bilateral * UFOF more useful
- If asymmetric – may experience diplopia
- Fresnel prisms / occlusion
- Ptosis props
- Surgery to straighten eyes allowing central fixation – select patients very carefully
- Cosmetic rather than functional
Ocular Myositis
Sub-group of idiopathic orbital inflammatory syndrome (previously pseudotumour)
- Inflammatory process involving one or more EOM
- Unilateral or bilateral
- Acute or chronic
Often occurs following respiratory tract infection
Ocular Myositis – features
Painful diplopia
* Affects horizontal muscles more than vertical: MR>LR,SR>IR * Pain worse on eye movement
- If 1 EOM involved
- Paretic in direction of muscle’s action
- Mechanical in opposite direction due to inflammatory process preventing muscle relaxation
- Orbital imaging shows swelling of affected muscles
- Proptosis
- Ptosis
Peri-ocular redness / swelling
Orbital Myositis - Differential Diagnosis
Graves’ Orbitopathy
- Lid retraction / Lid lag
- Dull pain
- Bilateral / asymmetrical
- Gradual onset
- Abnormal TFT
- Swelling of more than one EOM on CT, tendon sparing
Ocular Myositis
- No lid retraction/ lid lag
- Severe pain
- Unilateral typically
- Acute onset
- Normal TFT
- Swelling of one or more muscles plus tendon involvement
- Idiopathic orbital inflammatory syndrome – orbital myositis is a subgroup of this syndrome (diagnosis by exclusion) more commonly involves lacrimal gland and orbital fat
- Orbital Cellulitis – infective disease with systemic symptoms
Orbital Rhabdomyosarcoma – Tumour which usually occurs in childhood – rare for orbital myositis to occur at this age
Orbital Myositis - Management
Self limiting – 4-8 weeks, responds well to corticosteroids
* 1st days – EOM function normal * 11-14 – days paretic phase * 17-24 days – restrictive / mixed phase – resolve / permanent affect
Make comfortable with prisms whilst wait for recovery
Occlusion
If persistent motility problem (stable min. 3 months) – consider treatment
* BoToxA * Surgery only once stable and when patient off treatment – risk of further attacks Chronic - may come back
