Unilateral acquired ptosis can be the only sign of mitochondriopathy
U. Kretschmann 1, J. Schröder2, B. Lorenz 1
Introduction: Mitochondriopathy can be a cause of ptosis, but especially as part of syndromes like CPEO and Kearns-Sayre-syndrome or associated with generalized myopathies. We describe two patients with isolated ptosis in whom pathological changes of mitochondria of the levator muscle could be observed.
Patients and Methods: Patient 1: Female patient aged 19 with progressive ptosis of the right eye since age 9. 4 years before a tuck of the levator palpebrae muscle was performed followed by a levator resection 5 months later. She had full visual acuity, exophoria, and normal ocular motility, levator function right 9 mm, left 15 mm. Neurological examination normal. Normal EMG of M. deltoideus and M. sternocleidomastoideus, with polyphasic potentials in the M. frontalis left side. Patient 2: Female patient aged 21 years with a history of progressive ptosis right eye since five years. Full visual acuity, normal eye position and motility, levator function right 14 mm, left 16 mm, no retinal abnormalities, normal ERG. Regular neurologic status and normal EMG of the M. deltoideus and M. orbicularis, absent ACh-Ak, and normal ECG.
In patient 1 of frontalis brow suspension with biopsy of the levator palpebrae and in patient 2 resection of the palpebral levator muscle was performed. The resected muscle was fixed in Karnowsky's solution and examined by light and transmission electron microscopy.
Results: In patient 1 multiple muscle fibers with proliferation and hyperplasia of mitochondria were found. Abnormal mitochondria were found intermyofibrillar and especially in subplasmalemal and perinuclear localisation. In patient 2 an atrophy of muscle fibers was shown. The abnormal mitochondria exhibited circular cristae and pronounced intramitochondrial granula. In 20 % of normal muscle fibers a pronounced increase of mitochondria was found.
Conclusions: As reported previously by Siciliano et al. (Clin Neurol Neurosurg 94 (1992) 133-144) an isolated ptosis can be found in connection with pathological alterations in the mitochondria. Essential in cases of ptosis is a exact ophthalmological and neurological examination, EMG included as well as an ECG recording to exclude involvement of other structures. If a tissue sample of the levator palpebrae is collected during a therapeutic intervention, an electron microscopic examination of the muscles can essentially support the diagnosis.
1Dept. of Pediatric Ophthalmology, Strabismology and Ophthalmogenetics, 2Institute of Pathology, University Hospital, Franz-Josef-Strauß-Allee 11, D-93053 Regensburg