Horner Syndrome Flashcards
Q: What is Horner syndrome?
A: Horner syndrome is a neurological condition caused by disruption of the sympathetic nerves that supply the eye and surrounding facial muscles.
Q: What are the classic triad of symptoms associated with Horner syndrome?
A: The classic triad of symptoms includes ptosis (drooping eyelid), miosis (constricted pupil), and anhidrosis (lack of sweating) on the affected side of the face.
Q: Which part of the nervous system is affected in Horner syndrome?
A: The sympathetic nervous system is affected in Horner syndrome.
Q: What is the typical cause of ptosis in Horner syndrome?
A: Ptosis in Horner syndrome is caused by paralysis of the superior tarsal muscle (also known as Müller’s muscle), which is normally innervated by sympathetic fibers.
Q: What is anisocoria, and how does it relate to Horner syndrome?
A: Anisocoria is the difference in pupil size between the two eyes. In Horner syndrome, the affected eye’s pupil is smaller due to miosis.
Q: Which diagnostic test can confirm Horner syndrome?
A: The cocaine test or apraclonidine test can confirm Horner syndrome. Cocaine normally dilates the pupil by blocking the reuptake of norepinephrine, but in Horner syndrome, the pupil will not dilate. Apraclonidine (an alpha-1 antagonist) can cause a reversal of anisocoria due to denervation hypersensitivity.
Q: What are some common causes of Horner syndrome?
A: Common causes include trauma, tumors (like Pancoast tumor), carotid artery dissection, or lesions in the brainstem.
Q: How does carotid artery dissection cause Horner syndrome?
A: Carotid artery dissection can cause Horner syndrome by disrupting the sympathetic fibers that run along the artery, leading to the characteristic symptoms on the same side.
Q: What is the significance of the Pancoast tumor in relation to Horner syndrome?
A: A Pancoast tumor, located at the lung apex, can compress the sympathetic chain or stellate ganglion, leading to Horner syndrome on the same side as the tumor.
