1 Prepared by F.Rostami F.Rostami

 Invol­untary muscle contractions  Invol­untary muscle contractions  Shivering  Tremor  Tics  Tetany  Myoclonus  Seizures(Con­vulsions)  Opisthotonos 2

  This is a continuous, repetitive twitching (uncontrolled motions)of skeletal muscles, which is usually visible and palpable  The muscle units involved may be small and cause only local skin movement tremor is described as fasciculations  The muscle units may be extensive movement much coarser and sufficient to move the extremities, eyes or parts of the trunk  This usually being indicative of cerebellar involvement  Tremor 3

  Diffuse diseases of the cerebrum, cerebellum, spinal cord  Degenerative nervous system disease e.g. hypomyelinogenesis  Toxic nervous system disease caused by a large number of poisons, Clostridium botulinum toxin in shaker foal syndrome; hyperkalemic periodic paralysis in the horse early stages of hypocalcemia in the cow (fasciculations of the eyelids and ears)  Continue…. 4

  Spasmodic twitching movements made at much longer intervals than in tremor, the intervals being usually at least several seconds in duration  Easily visible  Caused by muscles that are ordinarily under voluntary control.  May occur after traumatic injury to a spinal nerve  Tics 5

  other name is backward tone  a continuous spasm of the neck and limb muscles resulting in dorsal and caudal extension of the head and neck with rigid extension of the limbs  Opisthotonos 6

  Tetanus is a continuous contraction of muscles without tremor  Most com­mon cause is Clostridium tetani intoxi­cation  The degree of muscular contraction can be exaggerated by stimu­lation of the affected animal and the limbs are rigid and cannot be passively flexed easily  Tetany 7

  Brief, intermittent tetanic contraction of the skeletal muscles that results in the entire body being rigid for several seconds, followed by relaxa­tion  Inherited congenital myoclonus  Horned and crossbred Hereford calves  Entire body becomes rigid for seconds  Myoclonus 8

  Violent muscular contractions affecting part or all of the body and occurring for relatively short periods  The convulsion may be clonic or tonic  (clonic): the typical 'paddling' involuntary movement in which repeated muscle spasms alternate with periods of relaxation  (tonic): less common and are manifested by prolonged muscular spasm without intervening periods of relaxation occur only rarely and chiefly in strychnine poisoning and in tetanus  Convulsions can originate from disturb­ances anywhere in the prosencephalon, including cerebrum, thalamus or hypothalamus  Con­vulsions are often subdivided into intracranial and extracranial  Convulsions ( seizures, fits, ictus ) 9

  Intracranial convulsions  Encephalomyelitis  Meningitis  Encephalomalacia  Acute brain edema  Brain ischemia, including increased intracranial pressure  Local lesions caused by trauma,abscess tumor, parasitic injury,  Hemorrhage  Inherited idiopathic epilepsy.  Continue…. 10

  Extracranial convulsions  Brain hypoxia, as in acute circulatory or cardiac failure  Toxic and metabolic diseases of the nervous system, including: Hepatic encephalopathy Hypoglycemia Hypomagnesaemia  Congenital and inherited defects convulsions and ataxia in Angus cattle  Continue…. 11

  Involuntary, intermittent contractions of large muscle masses may result in spas­modic movements of individual limbs or parts of the body  Stringhalt and Australian stringhalt of horses  Inherited spastic paresis of cattle  Inherited periodic spasticity of cattle  Inherited congenital myotonia of cattle  Inherited myotonia of goats  Involuntary spastic paresis 12