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Biomedical subjects

F Grand'Maison

Publications and source records attributed to F Grand'Maison.

13 recordsLinked to original sources

Diagnostic difficulties in myasthenia gravis.

Four patients with myasthenia gravis presented with severe, largely isolated, bulbar and respiratory muscles weakness. Tensilon tests were positive and antiacetylcholine receptor (anti-AChR) antibody titers were negative in all patients. Only 1 patient had a greater than 10% decremental response during the period of respiratory failure. Although routine nerve conduction studies were normal, all had very low-amplitude diaphragmatic compound muscle action potentials. Three patients had abundant fibrillation potentials and positive sharp waves largely restricted to respiratory muscles. Clinical and electrophysiological findings improved with corticosteroids, and surprisingly, decremental responses became positive in all patients. The assessment of patients with largely isolated bulbar and respiratory muscle weakness due to myasthenia gravis may be difficult and misleading, as anti-AChR antibody titers may be negative, decremental responses may be absent, and electrophysiological assessment atypical. Due consideration of clinical symptomatology, a Tensilon test, and a trial of immunosuppression may be necessary to establish the diagnosis.

Adult↗

Methods of testing neuromuscular transmission in the intensive care unit.

All disorders of neuromuscular transmission (NMT) may cause ventilatory failure, albeit rarely. Respiratory muscle weakness is occasionally the presenting feature of myasthenia gravis (MG), the Lambert-Eaton myasthenic syndrome (LEMS), hypermagnesemia and botulism. Chronic MG, congenital myasthenic syndromes and LEMS may be acutely exacerbated by various intercurrent conditions and by drugs which interfere with NMT. Finally, in the ICU, difficulty in weaning from the ventilator may be caused by prolonged use of neuromuscular blocking agents. Electrophysiological studies of NMT disorders in the intensive care unit have rarely been reported. Nevertheless, the available data indicates that the electrodiagnosis of severe NMT disorders can be misleading. With severe NMT defects, the electrophysiological distinction between post-synaptic and pre-synaptic disorders is blurred and the differential diagnosis with myopathies may be difficult. A clinically suspected NMT disorder should therefore not be ruled out when electrodiagnosis fails to demonstrate the expected abnormalities.

Electric Stimulation↗

Motor neuron disease presenting as acute respiratory failure: a clinical and pathological study.

Respiratory failure is rarely a presenting symptom of motor neuron disease. Seven patients with motor neuron disease who presented with acute respiratory failure of unknown cause and required mechanical ventilation were studied. They all had symptoms and signs suggestive of diaphragmatic weakness. Respiratory involvement seemed disproportionately severe, as six were ambulatory and only three noted limb weakness. Only one had tongue weakness and none had swallowing difficulty. Electrophysiological studies showed widespread denervation and, in particular, diaphragmatic involvement to explain the severe respiratory failure. Weaning from the ventilator was unsuccessful in all cases. The four patients examined at necropsy showed severe loss of anterior horns cells in the cervical cord, with only minimal upper motor neuron involvement. Motor neuron disease should be recognised as a cause of acute respiratory failure, secondary to diaphragmatic paralysis from involvement of phrenic motor neurons.

Acute Disease↗

Needle electromyography of the diaphragm.

A method is described for performing needle electromyography of the diaphragm which is safe and causes little discomfort. It provides valuable information concerning neuropathies and myopathies which may affect the diaphragm, and complements information derived from phrenic nerve conduction studies. Firing patterns of motor unit potentials during spontaneous respiration identify upper motor neurone disorders causing respiratory insufficiency.

Action Potentials↗

Partial status epilepticus: short-term prediction of seizure outcome from on-line EEG analysis.

Several combinations of ictal and interictal EEG abnormalities have previously been identified in partial status epilepticus (PSE). Some are associated with a consistently higher seizure index than others. On-line analysis of the initial segments of the EEG monitoring and familiarization with seizure indices corresponding to each combination may provide useful clues to rapidly foretell short-term seizure recurrence in patients with PSE. Referring to matrices reconstructed from an analysis of the initial min of the monitoring in 64 patients with recorded PSE can help to identify quickly those patterns which are most often associated with the highest probability of relapsing seizures. Awareness of the probability range of recording additional seizures observed with each of these various patterns may provide guidelines for judicious patient enrollment and for meaningful assessment of results in prospective studies of treatment efficacy in PSE.

Action Potentials↗

Recurrent Guillain-Barré syndrome. Clinical and laboratory features.

The clinical and laboratory features of recurrent Guillain-Barré syndrome (RGBS) were reviewed in 12 patients in whom a total of 32 episodes fulfilled accepted criteria for Guillain-Barré syndrome (GBS). All patients were asymptomatic or only mildly symptomatic between attacks. In a given patient, the time to reach peak deficit from the onset of symptoms, the functional grade at peak deficit and the duration of the intervals between episodes varied considerably and unpredictably from one episode to the next. Analysis of these parameters across the entire group revealed no significant change as the number of attacks increased. The distribution of weakness varied between episodes with the possible exception of features of the Miller Fisher variant which were more constant. Tremor was noted in two patients and enlarged nerves in one patient. There was no evident response to immunosuppressive therapy. Results of cerebrospinal fluid (CSF) analysis and nerve conduction studies during recurrences were those expected in typical monophasic GBS. On nerve biopsy, onion bulb formations were sometimes observed after several recurrences. The following characteristics of RGBS may be sufficiently distinctive from those of chronic relapsing polyneuropathy to justify their nosological separation: rapid onset of symptoms with subsequent complete or near complete recovery, high incidence of an antecedent illness, lack of an apparent response to immunosuppressive therapy and normal CSF protein levels at the onset of a recurrence.

Adolescent↗

Periodic lateralized epileptiform discharges with transitional rhythmic discharges: association with seizures.

Low amplitude rhythmic discharges (RDs) closely associated in time and in spatial distribution to inter-ictal epileptiform discharges are not seen in scalp EEGs of patients with non-periodic focal epileptiform discharges (NPEDs) but they are unexpectedly common in patients with periodic lateralized epileptiform discharges (PLEDs). A classification of PLEDs into PLEDs Proper (PLEDs without RDs), and PLEDs Plus (PLEDs with RDs) is proposed. Such a classification is useful for an easier appreciation of PLEDs' pleomorphism. It underscores the changing periodicity of PLEDs and allows for a more inclusive definition of the phenomenon than the one reported by the literature. It also emphasizes the importance of recognizing RDs in scalp EEGs as transitional anomalies intercalated between inter-ictal PLEDs and ictal seizure discharges, analogous to those observed by Ralston in animal models. Indeed, the occurrence of recorded seizures is higher in patients with PLEDs Plus than in those with PLEDs Proper or NPEDs.

Electroencephalography↗

Retrospective inventory of EEG abnormalities in partial status epilepticus.

In this retrospective study, EEG activity in partial status epilepticus (PSE) was classified into different patterns from analysis of both ictal and interictal discharges. In 64 patients with recorded PSE, continuous seizures and closely spaced seizures interrupted by only brief flat periods were uncommon. PLEDs, defined as classic periodic lateralized epileptiform discharges, and PLEDs Plus, defined as PLEDs associated with stereotyped low amplitude, were the most common abnormalities. PLEDs and PLEDs Plus can each occur alone or sequentially (sequential PLEDs) between consecutive seizures. The quantity of ictal activity was significantly lower with PLEDs, sporadic spikes and with the absence of epileptiform abnormalities than with PLEDs Plus and sequential PLEDs. EEG monitoring is important to gauge the effectiveness of treatment, particularly in patients with patterns associated with a high incidence of seizure activity, namely continuous seizures with or without flat periods, sequential PLEDs and PLEDs Plus. From serial recordings, a sequence was reconstructed which may be relied upon to further assess the need for additional energetic therapeutic measures. The reconstructed sequence differed in patients with chronic lesions since sequential PLEDs and PLEDs Plus were identified exclusively in patients with acute or subacute lesions.

Adult↗

Peripheral nerve function in sepsis and multiple organ failure.

Forty-three patients who had sepsis and multiple organ failure (critical illness) were studied prospectively to determine the incidence and severity of peripheral nerve function and to correlate such function with a number of variables. Electrophysiologic studies indicated a primary axonal degeneration of motor and sensory fibers in 30 (70 percent). Fifteen (30 percent) had the clinical signs of difficulty in weaning from assisted ventilation, weakness of limb muscles, and reduced or absent deep tendon reflexes. Full recovery from the polyneuropathy occurred among the 23 (53 percent) who survived, except three who had a very severe polyneuropathy. A peripheral nerve function index, computed from electrophysiologic measurements, showed statistically significant (p less than 0.01) negative correlations with the time in the critical care unit, and the serum glucose value; the serum albumin level showed a positive correlation. Multiple regression analyses indicated all three factors accounted for 47 percent (r2 = 0.4678) of all potential variables. In a separate analysis, the nerve function index correlated with the amplitude of the diaphragm compound muscle action potential (p less than 0.01). The results were consistent with the polyneuropathy being due to the same mechanisms that are currently postulated to cause dysfunction in this syndrome of other organ systems (including the neuromuscular respiratory system).

Bacterial Infections↗

Transient anosognosia for episodic hemiparesis: a singular manifestation of TIAs and epileptic seizures.

Anosognosia is a well-known manifestation of non-dominant parietal lobe lesions and typically lasts a few days. That anosognosia may last only a few minutes to a few hours, as observed in six patients, has not been reported. In five patients, transient anosognosia for equally brief left-sided hemiparesis was a manifestation of transient ischemic attacks (TIAs). In the sixth patient, anosognosia for both a left-sided motor seizure and a subsequent brief left hemiparesis could best be explained by an epileptic ictal and post-ictal transient dysfunction of the non-dominant parietotemporal cortex. Prompt recognition of transient anosognosia, whether ischemic or epileptic, is mandatory for proper diagnosis and for rapid initiation of specific therapy.

Aged↗