Cherry-red spot myoclonus syndrome and alpha-neuraminidase deficiency: neurophysiological, pharmacological and biochemical study in an adult

A 22 year old patient with non-familial progressive myoclonus, macular cherry-red spot, moderate cerebellar syndrome and normal intelligence is described. The myoclonus began at the age of 18 years. Focal myoclonus could easily be elicited by voluntary and passive movements, and by touch and electrical stimulation of median nerve. Somatosensory evoked potentials showed a high voltage early component. Jerk-locked averaging of the EEG preceding action myoclonus detected an otherwise hidden, time-related, EEG spike. The myoclonus responded partially but clearly to L-5 hydroxytryptophan plus carbidopa treatment. Biochemical study showed an alpha-neuraminidase deficiency in cultured fibroblasts: the decrease in this enzyme activity was compared to that found in a patient affected by mucolipidosis III.     

Treatment of myoclonus with l-5-hydroxytryptophan and carbidopa: Clinical,electrophusiological, and biochemical observations

Six patients with myoclonus of varying cause were treated with L-5-hydroxytryptophan (L-5-HTP) and carbidopa. While spontaneous myoclonus decreased in three of the patients and action myoclonus in four, only two patients had marked functional improvement. Side effects included gastrointestinal and affective disturbances. L-5-HTP therapy caused a diminished frequency of paroxysmal discharges in the electroencephalograms of three patients which did not always correlate with clinical improvement. Lumbar cerebrospinal fluid 5-hydroxyindoleacetic acid (5-HIAA) concentration after probenecid was decreased in all patients prior to therapy, but this reduction did not predict treatment response. Urinary excretion patterns for 5-HTP, serotonin, and 5-HIAA during treatment were similar in responders and nonresponders. It is concluded that while some patients with myoclonus do benefit from L-5-HTP therapy, biochemical and electrophysilogical tests are not useful predictors of treatment response, and the high incidence of side effects limits the usefulness of this therapy.     

Clinical, biochemical, and physiological features distinguishing myoclonus responsive to 5-hydroxytryptophan, tryptophan with a monoamine oxidase inhibitor, and clonazepam.

Fifteen patients with a variety of myoclonic syndromes were studied clinically, pharmacologically, and physiologically. CSF tryptophan, 5HIAA, and HVA were also measured. Of these patients, 8 were improved to varying degrees by therapy with 5HTP, tryptophan in combination with MAOI (but not tryptophan alone), and clonazepam. This group included 6 cases of post-anoxic myoclonus, one case of post-traumatic myoclonus and one undiagnosed case of non-progressive focal myoclonus and epilepsy. In this group low levels of CSF 5HIAA were found compared to non-responsive cases and controls. Two cases of dysynergia cerebellaris myoclonica, 2 cases of undiagnosed aetiology, 2 cases of essential myoclonus, and one case of palatal myoclonus failed to respond to drug therapy. However, even amongst the responsive group the improvement varied. The most dramatic responses were seen in those patients in whom physiological study suggested that myoclonus was mediated by brain-stem structures. Less dramatic responses were seen in patients in whom the myoclonus appeared to originate from cortical structures. The neurochemical basis of myoclonus responding to 5HT precursors and clonazepam is discussed. It is suggested that such myoclonus arises from a relative hypoactivity of the 5HT neuronal system which results in a release of abnormal responses to sensory stimuli which characterize this type of myoclonus.     

Generalized reflex myoclonus in a patient with alcohol-sensitive spontaneous myoclonus and an abnormal gait

A patient with alcohol-sensitive spontaneous, action- and stimulus-sensitive generalized reflex myoclonus is reported. Gait was abnormal but could not be clearly classified as dystonic. No other neurological abnormality was present. The possible relationship between alcohol-sensitive myoclonic dystonia and this case is discussed. Reflex myoclonus may serve as an additional clinical marker in the study of families with alcohol-sensitive myoclonus, dystonia, or both.     

Periodic myoclonus due to cytomegalovirus encephalitis in a patient with good syndrome

BACKGROUND: Good syndrome (GS) refers to a constellation of thymoma and adult-onset immunodeficiency characterized by low or absent B cells, hypogammaglobulinemia, and variable defects in cell-mediated immunity with an inverted CD4/CD8(+) T-cell ratio. Patients may develop severe or chronic infections as a result of this immunodeficiency. OBJECTIVE: To describe a patient with GS who developed cytomegalovirus (CMV) encephalitis and showed a periodic electroencephalographic pattern and myoclonus. DESIGN: Case report. SETTING: Outpatient neurology clinic at a university medical center. Patient A 64-year-old man who developed periodic myoclonus involving the right half of his body and the left arm. RESULTS: Five years previously, the patient had undergone resection of a pathologically confirmed epithelial thymoma. Quantitative CMV polymerase chain reaction of the serum and cerebrospinal fluid showed strongly positive results (1:10 000), allowing the diagnosis of CMV encephalitis. CONCLUSIONS: To the best of our knowledge, myoclonus and periodic electroencephalographic pattern have not previously been reported in CMV encephalitis. Opportunistic CMV infection should be considered early in the evaluation of patients with GS or a history of thymoma who develop unusual neurological symptoms.     

Spinal myoclonus in association with brain death

A 56-year-old, hypertensive man was admitted to our hospital because of confusion. He had been well unit half an hour before admission, when he had suddenly developed left hemiplegia. Although he became deep coma soon after admission, his vital signs were preserved. CT scan revealed a large right putaminal hemorrhage and a ventricular perforation. The condition was too severe for surgical approaches and conservative therapy for brain edema was performed. On the 2nd hospital day, corneal and light reflexes were disappeared and an anisocolia appeared. On the 3rd hospital day, right papilledema appeared. Doll's head-eye movements and ciliospinal reflexes were absent. CT scan demonstrated marked brain edema and collapsed ambient cisterns. Tentorial herniation were suspected. On the 4th hospital day, respiratory arrest occurred and ventilatory assistance began. On the 11th hospital day, electroencephalograms (EEG's) showed electrocerebral silence. EEG's performed next day showed still electrocerebral silence. On the 13th hospital day, brainstem auditory evoked potentials were recorded without any responses. He was thought to be in condition of brain death. On the 17th hospital day, multifocal myoclonus involving lower limbs and abdominal muscles appeared. The myoclonus lasted for about 15 hours occurred on both sides, but was asymmetrical. The myoclonus consisted of intermittent, brief, arrhythmic, stereotype, jerking contractions of the muscles. Sometimes, the contractions were sufficient enough to jump his body over the bed. These symptoms provided the characteristics of spinal myoclonus. Etiologies of spinal myoclonus are varied, but the primary abnormality exists within the spinal cord.(ABSTRACT TRUNCATED AT 250 WORDS)     

Clinical and biochemical improvement following HSCT in a patient with MNGIE: 1-year follow-up

Journal of Neurology -     

Reserpine responsive myoclonus and hyperpyrexia in a patient with Angelman syndrome

A case of an older patient with the Angelman syndrome due to a deletion at the 15q11-q13 region is presented. The patient demonstrated generalized prolonged myoclonus severe enough to produce temperatures of 41.4 degrees C and CPK elevations to 7281 U/l. This myoclonus was unresponsive to benztropine, clonazepam and worsened with bromocriptine. It resolved with sleep induced by either lorazepam or diphenhydramine and during treatment with reserpine. Once discharged from the hospital and treated with reserpine, there were much less frequent recurrences of the myoclonus that responded well to concomitant treatment with clonazepam. Later attempts to reduce the reserpine resulted in worsening of the myoclonus. Older patients with Angelman syndrome may display a wide variety of neurologic syndromes. This severe myoclonus in this patient worsened with dopamine agonist treatment and initially improved with dopamine depletion therapy while in the long-term responding best to a combination of clonazepam and reserpine.     

Pregabalin-induced cortical negative myoclonus in a patient with neuropathic pain

Myoclonus is a well-known side effect of anticonvulsant drugs. Pregabalin is one of the newer drugs approved for the treatment of focal epilepsies. Frequently it is also used to treat chronic pain syndromes. We describe a patient who, after receiving his first dose of pregabalin to relieve neuropathic pain, presented with a negative myoclonus. Clinical aspects and electrophysiological data such as polygraphic studies, electroencephalography, and measurement of somatosensory evoked potentials support the cortical origin of negative myoclonus. Our findings reveal that even in patients without a history of seizures, pregabalin can cause a cortical negative myoclonus.     

Palatal myoclonus and unusual MRI findings in a patient with membranous lipodystrophy

We describe an Italian male patient, deceased at 29 years of age, affected with a syndrome characterized by childhood-onset seizures, mental disorders, motor dysfunction and bilateral palatal myoclonus. Skeletal X-ray examination showed diffuse osteopenia of the tubular bones, and cyst-like lesions in the carpal, metacarpal and tarsal bones bilaterally and in the proximal end of the right femur. Skin biopsy showed subcutaneous and adipose tissue containing membranocystic structures. Cerebral MR and CT scans showed fronto-temporal atrophy, altered signal of the white matter and mineralization of the caudate and dentate nuclei. These findings strongly recall polycystic lipomembranous osteodysplasia with sclerosing leukoencephalopathy, but in the present case, bone alterations were not prominent; moreover, palatal myoclonus has never previously been described in this syndrome.     

High-frequency rhythmic cortical myoclonus in a long-surviving patient with nonketotic hypergylcemia

An 11-year-old girl with nonketotic hyperglycinemia who typically presented with a picture of early myoclonic encephalopathy in the neonatal period is presented in this article. Treated early with sodium benzoate and dextromethorphan, she became seizure-free, while myoclonus persisted. During examination, multifocal rhythmic myoclonic jerks in gamma frequency enhanced by motor activity were noted. Coherence analysis of the electroencephalography-electromyography relationship indicated a cortical origin of the myoclonic jerks. Observation of this case suggests that rhythmic cortical myoclonus may represent a late evolution of this rare disorder.