Neuro clinics 31- The pupils -basic
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Neuro clinics 31- The pupils -basic

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the pupils

the pupils

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Neuro clinics 31- The pupils -basic Neuro clinics 31- The pupils -basic Presentation Transcript

  • Neuro-Clinics 31 The pupils Dr Pratyush Chaudhuri Supported by Nirmal Clinics
  •  
  • Basics
    • Pupils are controlled by constrictor fibres supplied by parasympathetic nerves.
    • Radial fibres controlled by sympathetic fibres
  • Basics
    • Resting size depends on the amount of light falling on the eye and depends on the integrity of the parasymapthetic system.
    • Increased activity of the symapathetic system is reflected in the slight dilatation of the pupils.
    • Small pupils are asymptomatic because of ability to focus close.
    • Dilated pupils cause blurring of vision o close vision.
  • Parasympathetic pathway
  •  
  • Afferent pathway lesion
    • Marcus Gunn Pupil
    • When the eye is stimulated with bright light – there will be sustained constriction of pupil
    • If the abnormal eye is stimulated there will be an ill-sustained constriction followed by dilatation. (Pupillary escape phenomenon)
    • Due to decrease in the number of fibers sub serving the light reflex.
    • Wernike’s pupillary reaction
    • A lesion of one side optic tract affects the direct reflex
    • but if properly shown properly to the unaffected half of the same eye – reflex may be elicited.
  •  
    • Lesions compressing or infiltrating the tectum of the midbrain (area of the sup collicular bodies) will interfere with the decussating fibers o the peri-aqueductal area
    • Results in fixed semi-dialted pupils with loss of upward gaze.
    • Parinaud syndrome
  • Argyll Robertson pupil
    • Small irregular , fixed to light but reactive to accomodation
    • Due to lesion in the Edinger Westphal Nu
    • Causes – neurosyphilis, pinealomas, diabetes, wernicke’s encephalopathy, brainstem encephalitis and multiple sclerosis.
    • Cannot be dilated with atropine
  • Reverse Argyll Robertson pupil
    • Rare
    • Asociated with epidemic encephalitis lathergica
    • Pupils react to light but not to accomodation.
  •  
  •  
  • Adie pupil or tonic pupil
    • Possible viral cause
    • Associated with loss of sweating and knee jerks
    • Widely dilated circular pupil that may react very slowly to very bright light but more definite to accomodation.
  •  
  • Sympathetic pathways
    • Starts in the hypothalamus
    • Considerable degree of cortical ipsilateral control
    • Three neurons
    • Hypothal to lateral grey in sp cord C8 -T1 – celio-spinal centre of Budge
    • From spinal cord to superior cervical ganglion via white rami of nerve root C8 – T1
    • From superior cervical ganglion to the blood vessels and pupil
  •  
  •  
  • activity
    • Innervate sup and inferior tarsus muscles of Muller and orbitalis (causes “upside down’’ ptosis)
    • Nasociliary vasomotor fibers --- ciliary ganglion---- blood vessels of the eye.
    • Pupillo-dilatation
  • Abnormalities of sympathetic pathway
    • Horners syndrome
    • Miosis
    • Ptosis
    • Congested conjunctiva
    • Hyper or hypo hedrosis
    • Heterochromia in congenital horners
    • Apparent enopthalmos
  • Hemisphere level
    • After thalamic bleed, hemispherectomy & massive infarction
    • Ipsilateral
  • Brain stem level
    • Associated with spinothalamic tract so there will be pain and temperature loss on the opposite side.
    • Vascular lesions, MS, pontine gliomas and brain stem encephalitis
    • Associated with anhydrosis
  • Cervical cord level
    • Associated with central cord lesions (loss of pain sensation in the arm, loss of arm reflexes and sometimes bilateral Horners)
    • Anhydrosis
    • Causes: syringomyelia, glioma, ependymoma and cervical trauma.
  • Root lesion at T1
    • Pancoast syndrome ( wasting of small muscles of the hand, severe nocturnal pain in shoulder and axilla & horners syndrome) due to metastasis to apical pleura.
    • Cervical rib
    • Avulsion of lower brachial pexus (klumpke’s paralysis)
    • Aneurysm of aortic arch.
  •  
  • Sympathetic chain
    • No anhydrosis
    • Due to causes in the neck
    • Occlusion of carotid art, dissection of carotid art, migraine, malignancies, irradiation of neck
  •  
  • Pupillary abnormalities in the unconscious
    • Normal
    • Unequal
    • Bilateral dilated
    • Bilateral pinpoint
  • Reaction Small (miotic) pupil Large (mydriatic) pupils Non-reactive to light A-R pupils Pontine hemorrhage Opiates Pilocarpine drops
    • HA pupils
    • Post traumatic irridoplegia
    • Atropine
    • Overdosage of glutethemide, amphetamine, cocain or derivatives
    • Poisoning: belladona, dhatura
    • Brain death
    Reactive to light Old age Holmes Adie pupil Horners syndrome Anisocoria Iritis Anxiety Childhood Physiological anisocoria
  • That’s all folks