Pupils

Question 1

Light reflex

Answer 1

Neurons 1. (sensory) - retina with both pretectal nuclei in the midbrain at the level of the superior colliculi. 2. (internuncial) - pretectal nucleus to both Edinger-Westphal nuclei. damage - light-near dissociation in neurosyphilis and pinealomas 3. (preganglionic motor) - Edinger-Westphal nucleus to the ciliary ganglion. 4. (postganglionic motor) - leaves ciliary ganglion and passes in the short ciliary nerves to innervate the sphincter pupillae

Question 2

Neurons of sympathic supply

Answer 2

1 (central) posterior hypothalamus -> ciliospinal centre of Budge in the intermediolateral horn of the spinal cord C8-T2. 2 (preganglionic): ciliospinal centre -> superior cervical ganglion in the neck. 3 (postganglionic) along internal carotid artery -> cavernous sinus -> joins ophthalmic division of the trigeminal nerve -> nasociliary nerve and long ciliary nerves -> ciliary body and dilator pupillae muscle

Question 3

Central (first order neurone)

Answer 3

brainstem disease (stroke, tumor, demyelination), syringomyelia, lateral medullary (Wallenberg) syndrome, cervical spinal cord lesions, diabetic autonomic neuropathy

Question 4

Preganglionic (second-order neurone)

Answer 4

pancoast tumor, carotid and aortic aneurysm and dissection, thoracic spinal cord lesion, thyroid tumor, enlarged lymph nods, trauma, postsurgical)

Question 5

Postganglionic (third-order neurone)

Answer 5

internal carotid artery dissection, nasopharyngeal tumor, cavernous sinus mass, otitis media, cluster headache (migrainous neuralgia).

Question 6

Most commonly, isolated postaganglionic

Answer 6

microvascular in aetiology

Question 7

bilateral Horner’s

Answer 7

cervical spine injuries, autonomic diabetic neuropathy

Question 8

Apraclonidine 0,5% or 1,0% - when can you use it

Answer 8

(no for acute, takes at least 14 days to become positive)-> 30 min, 45 mins, no infants, no tests in 3-5 days

Question 9

Apraclonidine 0,5% or 1,0% - effect

Answer 9

Horner dilates,normal no, ptosis improves. alfa-1 receptors are upregulated in the denervated dilator pupillae

Question 10

Cocaine 4% - effect

Answer 10

(for acute): normal pupil dilates, Horner will not. anisocoria as little as 0.8mm in a dimly lit room. Cocaine blocks the re-uptake of noradrenaline secreted at the postgang nerve ending, which accumulates and causes dilatation of normal. Horner no noradrenaline secreted

Question 11

Cocaine 4% - when

Answer 11

for acute

Question 12

Phenylephrine 1% - when

Answer 12

In established (10 days)

Question 13

Phenylephrine 1% - effect

Answer 13

POSTgang lesion, the Horner will dilate and ptosis temporarily relieved. A central or PREgang Horner and normal will not dilate or dilate minimally. In post dilator pupillae develops denervation hypersensitivity to adrenergic neurotransmitters due to its dysfunctional local motor nerve

Question 14

Hydroxyamphetamine 1% 2 drops - effect

Answer 14

Normal or PREgang will dilate, but a postgang will not. This agent potentiates the release of noradrenaline from functioning postgang nerve endings. In postgang there is no release of noradrenaline from the dysfunctional nerve

Question 15

Holmes-Adie syndrome

Answer 15

Adie (tonic) pupil + diminished lower limb deep tendon reflexes

Question 16

Ross syndrome

Answer 16

Adie (tonic) pupil + excessive sweating

Question 17

Adie (tonic) pupil - test

Answer 17

0.125 or 0.1% Pilocarpine –> constriction of the abnormal pupil, normal unaffected

Question 18

Physiological anisocoria

Answer 18

1mm, 20% of normal population

Question 19

Tectal (dorsal midbrain) pupils

Answer 19

Pupils dilated in both dim and bright light. Light-near dissociation. Pilo has no effect.

Question 20

Benign episodic unilateral mydriasis

Answer 20

idio, healthy young woman, may migrainous phenomenon. Minutes or hours. may be mild blurring and headache. No or limited response to light or accommodation. 0,1% Pilo no change, but 1% pilo bi miosis

Question 21

Causes of unilateral light-near dissociation

Answer 21

afferent conduction defect, Adie pupil, Herpes Zoster ophthalmicus, Aberrant regeneration of the third cranial nerve

Question 22

Causes of bilateral light-near dissociation

Answer 22

Neurosyphilis, DM I, Myotonic dystrophy, Parinaud (dorsal midbrain) syndrome, Familial amyloidosis, Encephalitis, Chronic alcoholism