Chronic progressive external ophthalmoplegia (CPEO)
Clues
- Common adult presentations of mitochondrial disease
Clinical features
- Classic: ophthalmoparesis + ptosis
> Pupil sparing
- Possible: proximal limb myopathy + bulbar involvement + reduced respiratory muscle strength
Presentations
- Isolated CPEO vs CPEO-plus
> Isolated→ only eyes; with anything else is CPEO-plus
> Kearns-Sayre syndrome triad
(CPEO + pigmentary retinopathy + onset before 20yo)
Genetics
- Half of cases→ 4977-bp mtDNA deletion
- Other half is multiple deletions in mtDNA
> Common: POLG, TWNK (C10orf2), SLC25A4
Workup
- Labs: can ↑CK & ↑lactate
- EMG: myopathic changes
- Muscle biopsy→ ragged-red fibers & COX-negative fibers
- Cardiac eval→ ECG & TTE
> Cardiac conduction block→ KSS
- oMRI→ EOM atrophy
DDx
- Seronegative MG
- OPMD
- Congenital myasthenic syndromes
- Myotonic dystrophy
Ttx
- Supportive
- If ptosis→ surgery/ prisms
- CoQ10 and others, evidence is limited
- Avoid mitochondrial-toxic medications
General advice for mito myoapthies
1) Succinylcholine→ ↑HyperK adn rhabdo
2) Propofol→ ↑Propofol syndrome
3) Volatile anesthetics→ prefer sevo
4) Avoid LR→ impaired lactate metabolism