CAUSES OF ASTERIXIS (flabing tremor) Renal failure Liver failure Hypercapnic Resp Failure Drug toxicity (e.g. phenytoin) Acute focal parietal or thalamic lesions
Myoclonus: Brief, isolated, random, non-purposeful jerks of muscle groups in the limbs, may occur normally at the onset of sleep (hypnic jerks). A myoclonic jerk is a component of the normal startle response which may be exaggerated in some rare (mostly genetic) disorders. Unlike EP movement disorders, myoclonus may occur in disorders of the cerebral cortex, when groups of pyramidal cells fire spontaneously. Causes: M yoclonic epilepsy in which the jerks are fragments of seizure activity. Subcortical structures. Rarely, from diseased segments of the spinal cord. Treatment: Myoclonus, especially of cortical origin, often responds to clonazepam, sodium valproate or piracetam.
Tics: Repetitive semi-purposeful movements as blinking, winking, grinning or screwing up of the eyes. Distinguished from other involuntary movements by the ability of the patient to suppress their occurrence, at least for a short time. An isolated tic may be no more than a mild embarrassment, but may become frequent at certain times in childhood & then disappear. The uncommon syndrome of Gilles de la Tourette consists of a tendency to multiple tics & odd vocalisations, with obsessive behavioural abnormalities. The pathogenic basis is not understood, but there may be some response to major tranquillisers.
Movement disorder Site of lesion. Parkinsonism. Chorea. Dystonia& athetosis. Hemibalismus. Substantia nigra & corpus striatum. Caudate nucleus. Putamin & corpus striatum. Subthalamic nucleus.
Other movement disorders: Chorea Hemibalismus. Athetosis & dystonias: Tardive dyskinesia:
Chorea, athetosis, ballism & dystonia : <ul><li>Non-rhythmic involuntary movements may be combinations of fragments of purposeful movements & abnormal postures. </li></ul><ul><li>All due to imbalance of activity in the complex basal ganglia circuits. </li></ul>
Hemibalismus: <ul><li>Treatment in the same as chorea & sometimes by stereotactic thalamatomy. </li></ul><ul><li>More dramatic ballistic movements of the limbs usually occur unilaterally (hemiballismus) in vascular lesions of the subthalamic structures. </li></ul><ul><li>Wild flailing proximal movements of the arms & legs on one side of the body due to small vascular lesions of the contralateral thalamic nuclei occurring usually in elderly & ceases within few weeks . </li></ul>
Chorea(dance in Greek) : <ul><li>Jerky semipurposive uncontrollable movements of limbs , face & trunk ,increase with anxiety & disappear during sleep. </li></ul><ul><li>Jerky, small-amplitude, purposeless involuntary movements. </li></ul><ul><li>In the limbs they resemble fidgety movements, & in the face, grimaces. </li></ul><ul><li>They suggest disease in the caudate nucleus (as in Huntington's disease) or excessive activity in the striatum due to dopaminergic drugs used in Parkinson disease. </li></ul>
Athetosis & dystonias: <ul><li>Athetosis is slow writhing distal movements usually of fingers , hands ,toes & feet. </li></ul><ul><li>1. To twist, as in pain, struggle, or embarrassment. </li></ul><ul><li>2. To move with a twisting or contorted motion. </li></ul><ul><li>3. To suffer acutely. </li></ul><ul><li>Dystonias are sustained abnormal postures of limbs , neck ,trunk, torticolis, tongue protrusion or fixed upward deviation of the eyes ( occulgyric crisis). Both caused by birth injuries , kernictrus , hypoxia, vascular lesions & phenothiazines. </li></ul><ul><li>These are often combined with chorea (& have a similar list of causes)& are then termed 'choreo-athetoid' movements. </li></ul>
Athetosis & dystonias: <ul><li>Describe the movement disorder in which a limb (or the head) involuntarily takes up an abnormal posture. </li></ul><ul><li>This may be generalised in various diseases of the basal ganglia or may be focal or segmental, as in spasmodic torticollis when the head involuntarily turns to one side. </li></ul><ul><li>Other segmental dystonias may cause abnormal disabling postures of a limb to be taken up during certain specific actions, such as in writer's cramp or numerous other occupational 'cramps'. </li></ul>
Athetosis & dystonias: <ul><li>Treatment: </li></ul><ul><li>Anticholinergics as benzhexol , antihistamines, diazepam & baclofen . </li></ul><ul><li>Resistant dystonias as torticolis may respond to botulinium toxin injection or stereotactic surgery. </li></ul><ul><li>The segmental dystonias can be treated by botulinum toxin injection to the responsible muscles, to overcome the abnormal distribution of muscle activity for a period of time. </li></ul>
Tardive dyskinesia: <ul><li>Involuntary movements as facial grimacing , chewing movements ,tongue movements following the use of phenothiazine or buterphenones usually for some years. </li></ul><ul><li>thought to be due to receptors super sensitivity to these drugs . </li></ul><ul><li>Treatment is difficult but withdrawal of the causative drugs & giving drugs as sulpride or tetrabenazine may be helpful. </li></ul>
Paraneoplastic neurological features: <ul><li>Remote non metastatic neurological features of cancer. </li></ul>