ABSTRACT
Polysaccharide myopathy is a rare form of storage muscular disorder. The clinical picture of this particular form of myopathy is unspecific. We report a 62-year-old woman with late-onset progressive weakness and wasting, affecting proximal muscles of the four limbs and the girdles. No myalgia, dysphagia nor symptoms of cardiac failure were observed. Muscle biopsy revealed a vacuolar myopathy with accumulation of amylopectin-like polysaccharide. This material was strongly PAS-positive and diastase-resistant. At electron microscopy, the deposits were composed of non-membrane-bound filamentous and granular material surrounded by numerous mitochondria. No enzyme deficiency was found. Clinical presentation of our patient was similar to the 16 cases reported in the literature. She did not have myocardiopathy and her survival is much longer. Hypothetic mechanisms of polysaccharide accumulation are reviewed.
Subject(s)
Muscle Fibers, Skeletal/pathology , Muscle, Skeletal/pathology , Muscular Diseases/metabolism , Muscular Diseases/pathology , Polysaccharides/metabolism , 1,4-alpha-Glucan Branching Enzyme/metabolism , Adult , Aged , Amylopectin/metabolism , Biopsy , Cardiomyopathies/etiology , Cardiomyopathies/metabolism , Cardiomyopathies/physiopathology , Child, Preschool , Disease Progression , Enzymes/metabolism , Female , Humans , Inclusion Bodies/metabolism , Inclusion Bodies/pathology , Inclusion Bodies/ultrastructure , Male , Microscopy, Electron, Transmission , Middle Aged , Muscle Fibers, Skeletal/metabolism , Muscle Fibers, Skeletal/ultrastructure , Muscle Weakness/etiology , Muscle Weakness/pathology , Muscle Weakness/physiopathology , Muscle, Skeletal/metabolism , Muscle, Skeletal/ultrastructure , Muscular Diseases/physiopathologyABSTRACT
Botulism is a cause of neuromuscular transmission impairment. We report here an electrophysiological study of the neuromuscular junction in a patient presenting with botulism. Repetitive stimulation of a motor nerve showed a characteristic triad, indicating presynaptic block of neuromuscular transmission: the muscle action potential amplitude was low; repetitive high frequency stimulation (20 Hz) induced a more than 100% increment in the amplitude; low frequency repetitive stimulation (3 Hz) induced a more than 10% decrement in the amplitude. Progressive clinical improvement spontaneously occurred and the electrophysiological control recording that was done 1 month later was normal. Botulism toxin reduces acetylcholine quanta released in the autonomic and neuromuscular junction, causing presynaptic block. Electrophysiological recordings associated with clinical data contributed more to the diagnosis of botulism than serological analysis, which remained negative in this patients.
Subject(s)
Botulism/diagnosis , Electrodiagnosis/methods , Electromyography , Adolescent , Botulism/physiopathology , Humans , Male , Neuromuscular Junction/physiologyABSTRACT
The authors report the case of a girl whose development was normal until the age of eleven when epileptic seizures occurred. These were followed by loss of speech and auditory agnosia. The diagnosis of Landau-Kleffner syndrome was mode. The study of the auditory evoked response showed normal function of ear and brainstem auditory relays. On the other hand, the amplitude of the middle latency and late cortical responses were decreased. The relationship between these electrophysiological abnormalities and auditory agnosia are discussed.
Subject(s)
Evoked Potentials, Auditory , Landau-Kleffner Syndrome/physiopathology , Agnosia/physiopathology , Child , Evoked Potentials, Auditory, Brain Stem , Female , Humans , Landau-Kleffner Syndrome/etiologyABSTRACT
Two patients were bitten by tunisian cobras (Naja haje haje). A few hours after the bite they developed generalized paralysis which progressed to respiratory paralysis. Electrophysiological features are similar to those of myasthenia gravis and exhibit decremental pattern after stimulation at a frequency of three per second. It is probable that cobra neurotoxins act postsynaptically. The neuromuscular blocking activity of snake-venom can be reversed by intravenous neostigmine.
