Ophthalmoplegia plus: neuropathological and metabolic studies with a therapeutic trial in seven cases

Seven cases of chronic progressive external ophthalmoplegia (CPEO) have been studied. They all present palpebral ptosis, slowly progressive ophthalmoparesis without diplopia, descending myopathy and hypoacusia. Additional symptoms were small stature in 5 cases, vestibulo-cerebellar dysfunction in 4 cases, cardiac conductive defects in 6 cases, pigmentary degeneration of the retina in 2 cases, endocrine abnormalities in 2 cases. Muscle biopsy displays in all patients numerous ragged red fibers with typical mitochondrial changes, glycogen accumulation and abnormal amounts of lipid droplets. Metabolic studies reveal in all cases abnormal levels of pyruvic and lactic acid both in basal condition and after an oral glucose load. All the patients have been treated with pyridoxine-alpha-ketoglutarate (PAK). This substance is known to reduce pyruvic and lactic acid concentration in normal subjects after muscular exercise. Two months later a reduction of blood pyruvic and lactic acid both in normal condition and after oral glucose load was observed. The AA. discuss the possible physiological mechanism which can explain their findings.