False Localizing Sign111

6/27/09

“Neurological signs   that determine of the site or place of any process or lesion”

False localizing sign associated with intracranial lesion

“ Neurological signs that reflect dysfunction distant or remote from expected anatomical locus of pathology by clinicoanatomical correlation “

False localizing signs associated with spinal cord lesions

Sixth nerve palsy

Foramen magnum and upper cervical cord lesions

Fifth and seventh nerve palsy

Lower cervical cord and upper thoracic cord lesions

Third nerve palsy and Kernohan’s notch phenomenon

Other false localizing sign reported with intracranial pathology

• Unilateral or bilateral • Most common false localizing sign of intracranial tumor , IICP • Pathophysiology • Stretch nerve or compress against petrous ligament or ridge of petrous temporal bone • Mechanical effects of backward brainstem displacement by intracranial space occupying lesion

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• Hypoactive or hyperactive with negative or positive Jacksonian symptoms • Trigeminal neuropathy ,facial paisy • Trigeminal neuralgia ,Hemifacial spasm

  Trigeminal neuropathy , facial palsy ›  Causes   Posterior fossa tumor   Diffuse neoplastic disease   Idiopathic intracranial hypertension ›  Pathology   Traction CN in brainstem distortion from tumor   Trigeminal neuralgia ›  Causes   Posterior fossa tumor

, hemifacial spasm

  Causes

•  IICP   Hutchison ‘s pupil   Uncal herniation • Contralateral hemiparesis + Ipsilateral

CN III palsy

• Ipsilateral hemiparesis + Ipsilateral CN III

palsy “ Kernohan’s notch phenomenon”   Dynamic axial brainstem distortion {Transtentorial herniation}

  Trochlear

nerve palsy : IICP   Unilateral hearing loss : Idiopathic intracranial hypertension   Unilateral papilloedema : Foster Kennedy syndrome

  Glossopharyngeal

,Vagus nerve palsy : posterior fossa tumor   Frontal ataxia : cerebellar ataxia involve corticopontocerebellar pathway

›  Unilateral ,ipsilateral optic atrophy ›  Contralateral papilloedema ›  Central scotoma ›  Anosmia

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• Foramen magnum • Paresthesia in hands • Upper limb weak {LMNL} • Midline cervical disc protrusion at C3/4 level • Numb and clumsy hands • T ightening sensation at midthoracic level

  Compressive

cervical myelopathy

›  Midthoracic girdle sensation   High

thoracic cord compression

›  Lumbar sensory

1.Aterial hypothesis 2.Venous hypothesis 3.Mechanical hypothesis

  INO  

MG {pseudo-internuclear ophthalmoplegia}

  Nystagmus   MG { myasthenic nystagmus}   Pseudoathetosis  

and pseudoastereognosis

high cervical cord lesion

  Aphasia   subcortical lesion   Dysarthria   cortical lesion   Pseudosyringomyelia  

amyloid polyneuropathy ,Tangier disease

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