Hemiplegia

INTRODUCTION -

Paralysis of one side of the body due to Pyramidal tract lesion at any point from its origin in the cerebral cortex down to the fifth Cervical segment ( beginning of origin of cervical plexus ) .

ETIOLOGY

VASCULAR - Cerebral hemorrhage , Stroke , Diabetic Neuropathy.

INFECTIVE - Encephalitis , Meningitis , Brain abscess.

NEOPLASTIC - Glioma - meningioma

DEMYLINATION - Disseminated sclerosis , lesions to the Internal capsule .

TRAUMATIC - Cerebral lacerations , Subdural Hematoma . Rare cause of hemiplegia is due to local anaesthsia injections given intra arterially rapidly , instead of given in a nerve branch .

CONGENITAL - Cerebral palsy

DISSEMINATED - Multiple Sclerosis

PSYCHOLOGICAL - Parasomnia (Nocturnal hemiplegia ).

MECHANISM -

Damage to the corticospinal tract leads to the injury on the opposite side of the body. This happens because the motor fibres of the corticospinal tract , which take origin from the motor cortex in brain , cross to the opposite side in the lower part of medulla oblongata and then descend down in spinal cord to supply their respective muscles.

Depending on the site of lesion in brain , the severity of hemiplegia varies.

• INTERNAL CAPSULE -

Dense and uniform Hemiplegia ( UMN Facial )

Hemisensory blunting

Homonymous hemianopia

• CORTEX -

Non dense non uniform weakness

Monoplegia

Cortical signs ( Dysphasia , Apraxia , Cortical sensory loss , Convulsions )

• SUBCORTEX -

Pattern of weakness similar to cortical

• BRAINSTEM -

Crossed hemiplegia

Ipsilateral LMN CN Palsy and contralateral hemiplegia

Cerebellar signs.

• MIDBRAIN -

Crossed cerebellar ataxia with Ipsilateral Third nerve palsy ( Claude `s syndrome )

Weber`s syndrome - Third nerve palsy and contralateral hemiplegia

Contralateral hemiplegia - Cerebral peduncle

Contralateral rhythmic , ataxic action tremor ; rhythmic postural or holding tremor (rubral tremor)

• PONS -

LMN Facial and contralateral hemiplegia

Fifth nerve and contralateral hemiplegia

Lateral Gaze palsy and contralateral hemiplegia