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A 2-month-old infant with hereditary hyperekplexia, umbilical and bilateral inguinal hernias and history of poor feeding was noted to have severe normotensive metabolic alkalosis: sodium 132 mmol/L, potassium 3.4 mmol/L, chloride 77 mmol/L, pH 7.55, carbon dioxide tension 56.3 mmHg and bicarbonate 48.0 mmol/L. After parenteral rehydration and treatment with clonazepam, laboratory parameters normalized.
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The periodic nocturnal myoclonus of a patient with hyperexplexia has been studied. Evidence has been given that the jerks are spontaneous arousal reactions. The temporal characteristics of the jerks have been analysed. The jerks appear to be correlated with the respiratory rhythm and the data suggest a correlation of the jerks with circulatory and respiratory higher order waves. The results are discussed with relation to the literature concerning spontaneous sleep jerks.
Ten patients with Hodgkin's disease were examined before and after each administration of vincristine sulfate (2 intravenous injections of 1.4 mg/m2 of body surface during the first week of each month for 3 months). The motor conduction velocity of the peroneal nerve, the conduction velocity in palmar sensory fibres of the median nerve, and the conduction velocity in the H reflex pathway remained unchanged. The amplitude of distal muscle (extensor digitorum brevis) and sensory nerve (median) potentials decreased, while the maximal response of more proximal muscles (soleus) was not significantly modified. The soleus T response quickly decreased, although at the same time the H response was increased in the days following administration of vincristine. Thus the T/H ratio seems to be the only convenient electrophysiological method of evaluating the functional impairment of primary afferent distal segments. These results show that vincristine induces a transitory excitability enhancement of the monosynaptic reflex. It is suggested that the drug may cause an increase in the firing rate in proximal segments of injured Ia fibres. Apart from this phenomenon the electrophysiological results lead to the conclusion that vincristine induces distal axonal degeneration, similar to that in other toxic neuropathies (e.g. acrylamide or n-hexane) where a dying-back process has been clearly demonstrated.
Four patients with brainstem lesions presented with intractable hiccup and mild to moderate neurological signs. Two of the patients had been initially diagnosed as having a psychogenic cause for their hiccup. Magnetic resonance imaging (MRI) demonstrated brainstem infarction in one case, tuberculoma at the junction of the medulla oblongata and the cervical spinal cord in two, and a vermian tuberculoma compressing the brainstem in one. The brainstem infarct and one of the medullary tuberculoma were not detected on high resolution enhanced computed tomography. The 3 patients with CNS tuberculoma were free of hiccup 1-5 months after antituberculous chemotherapy. It is proposed that hiccup is not an abnormal reflex, but a myoclonus generated by repetitive activity of the "inspiratory solitary nucleus" due to release of higher nervous system inhibitory/-regulatory control. The neuroanatomical network and the mechanisms underlying the formation of intractable hiccup are outlined. The value of MRI in the initial diagnosis and follow-up of patients with intractable hiccup due to brainstem lesions is emphasised.
Recovery curves of the Hoffmann reflex (H reflex) were measured in both legs of 10 unmedicated inpatients with schizoaffective disorder, depressed type. Neither recovery curve height of the right leg nor that of the left leg was significantly correlated with clinical psychopathology, although a consistent negative relation was noted between recovery curve height of the left leg and psychopathology. Right-left differences in recovery curve height significantly correlated with both Brief Psychiatric Rating Scale and Hamilton Rating Scale for Depression ratings of psychopathology, such that relative elevation of the recovery curve of the right leg or relative lowering of the recovery curve of the left leg correlated with symptom severity. Three patients who later developed psychotic symptoms when treated with bupropion, a dopaminergic agent, had lower recovery curves, indicative of increased central dopaminergic activity. Relatively lower left-sided recovery curves may reflect increased dopaminergic activity on the right side of the brain in schizoaffective disorder, compared to the left in schizophrenia.
Patients who are tetraplegic with cervical spinal cord transection do not appear to have cerebral control over the sympathetic nervous system. Soon after transection they are often in a state of spinal shock during which even isolated spinal cord sympathetic activity is absent. This affects, in particular, the cardiovascular system and other homeostatic mechanisms which are dependent on appropriate regulation of the vasculature, such as thermoregulation. After a few weeks isolated spinal cord activity returns but the absence of control absence of control by the brain results in sympathetic malfunction of various systems. Inappropriate inactivity therefore occurs during postural change and causes orthostatic hypotension, while over-activity, which results in the syndrome of autonomic dysreflexia and hypertension, occurs if spinal sympathetic reflexes are activated. Examples are provided of clinical effects of sympathetic malfunction in tetraplegics in relation to circulatory, thermoregulatory, pupillary, genital, gastrointestinal and urinary tract function.
Three cases of congenital cytomegalovirus (CMV) infection with long-term audiovestibular sequelae are presented. Case 1 had no hearing in one ear and severe progressive hearing loss in the other ear; he showed vestibular symptoms at the age of 4.5 years. Case 2 had severe but stationary hearing loss in one ear and showed hearing impairment symptoms in the other ear at 9-13 years of age. Case 3 did not have hearing impairment symptoms, or vestibular symptoms, but was found to have severe progressive hearing loss from the age of 15 months onwards, which led to profound deafness at the age of 2 years and vestibular areflexia at or before the age of 4 years. These cases may represent 3 symptomatically different types of delayed endolabyrinthine hydrops. Type 1 (ipsilateral hydrops) incorporates vestibular symptoms only because of a lack of hearing in the offending labyrinth. Type 2 (contralateral hydrops) incorporates hearing impairment symptoms only because of a lack of vestibular function on both sides and type 3 does not incorporate hearing impairment symptoms or vestibular symptoms (other than those relating to a complete lack of function). Given the present findings, those described by Weiss and Ronis (Trans. Pa. Acad. Opthalmol. Otolaryngol., 30 (1977) 52-54) in one case and other reported findings relating to histopathological or imaging methods in somewhat similar cases, it seems appropriate to include congenital CMV infection in the differential diagnosis of delayed endolymphatic hydrops.
BACKGROUND/AIMS: Autonomic and cardiac dysfunction have been reported in patients with cirrhosis. We studied left ventricular and autonomic function in 20 patients with both alcoholic and non-alcoholic cirrhosis. METHODS: Autonomic function was assessed by a standard battery of cardiovascular reflex tests. Supine exercise radionuclide ventriculography was used to assess the cardiac response to exercise. RESULTS: Exercise capacity was reduced in all patients in association with marked chronotropic incompetence (peak heart rates 120.5 +/- 6 bpm). Unlike normal subjects there was no increase in left ventricular ejection fraction on exercise. Stroke volume increased by 23 +/- 6%, mediated by an increase in end-diastolic.volume of > 20%. Cardiac output was subnormal at maximal exercise, increasing by only 96 +/- 14% and 97 +/- 11% in alcoholic and non-alcoholic groups respectively. The majority (83%) of our patients had autonomic reflex abnormalities. CONCLUSIONS: Patients with cirrhosis of alcohol and non-alcohol related aetiologies have significantly impaired cardiovascular responses to exercise, which are similar to those of a denervated heart. This may have important clinical implications for the ability of these patients to withstand cardiovascular stress.
When clioquinol was administered to Beagle dogs, disturbances in gait which were associated with abnormal reflexes and reactions, were seen in animals receiving 250 and 400 mg/kg body weight per day. Histopathological examination of the central nervous system (CNS) showed pathological change in the posterior columns of the spinal cord.
Changes in excitability of the soleus (Sol) monosynaptic reflex arc were investigated in spastic subjects, affected by amyotrophic lateral sclerosis (ALS), upon voluntary relaxation of tonic contraction of triceps surae muscle. Force and electromyograms (EMG) were recorded during triceps release, performed in response to an acoustic signal, in a reaction-time (RT) situation. Sol H-reflex was evoked at random during the task, and its amplitude was referred in time to the end of Sol EMG. At variance with the results for the same task in normal subjects, it was found that in ALS patients the RTs of the termination of EMG were longer than those of the beginning of the EMG, the decrease in force was prolonged and perturbed owing to intercurrent clonus-like EMG activity, and the H-reflex did not undergo the expected profound inhibition. It is suggested that the absence of the activation of presynaptic inhibitory mechanisms by the descending command to release brings about major disorders in voluntary muscle relaxation.
Disruption of neuromuscular contact by nerve-crush during the early postnatal period results in the death of a large proportion of affected motoneurons. Increased activity and abnormal reflex responses are evident in those that survive. We have studied the aberrant dendritic morphology of surviving cells and have attempted to correlate the observed alterations in morphology with the above experimental findings. Motoneurons supplying the extensor hallucis longus muscles of the rat were retrogradely labelled with cholera toxin subunit-B conjugated to horseradish peroxidase. The dendritic tree of labelled cells was analysed in adult animals having undergone unilateral sciatic nerve-crush at birth. Unoperated control animals were also examined. Following nerve-crush at birth, total visible dendritic length was more than 30% smaller than control cells in the transverse plane. This decrease was confined largely to the medially directed segments of the dendritic field and appeared to be due to a reduction in dendritic branching combined with a failure to achieve the correct branch length. There was no overall change in total visible dendritic length in the longitudinal plane, but a reorientation of dendrites in favour of rostrodorsal regions was observed. There was no alteration in dendritic length in cells contralateral to the nerve injury. These results show that nerve injury during early postnatal development produces lasting changes in the distribution of motoneuron dendrites. The localized nature of these changes may explain the altered activity and induced death of motoneurons seen after neonatal nerve-crush.