A 25-year-old patient, during a tennis match, has severe pain in his neck and left eye. The next morning he wakes up with a feeling of gait instability and has palpebral ptosis of the left eye and anisocoria, with the left pupil being smaller than the right. The patient maintains good visual acuity, where would you most likely locate the lesion?
Claude-Bernard-Horner syndrome is an old acquaintance of the MIR exam. We do not see it daily in clinical practice, but it appears in many exams. Characteristic is upper eyelid ptosis and miosis of that eye. This occurs due to a deficit of sympathetic innervation of the orbital territory. The sympathetic nervous system innervates the Müller muscle, which is an accessory muscle to the levator of the upper eyelid. If the Müller ceases to function, the eyelid descends slightly. It also innervates the iris dilator muscle. Therefore, the sphincter muscle, its antagonist, is unopposed and the balance of the pupil shifts toward miosis. It explains ptosis and miosis of the left eye, so we suspect Horner's in that eye. She also describes what may have happened: after a possible sudden movement while playing tennis, she has neck pain and a Horner's. We should suspect an aneurysm. We should suspect a dissecting carotid aneurysm, which is one of the best known (and most serious) causes of an acquired Horner's syndrome. The superior cervical ganglion is a ganglion of the sympathetic nervous system located in the sheath of the carotid artery, and at this level it has been affected. We can also try to get this answer right by ruling out. An alteration of the III cranial nerve can produce ptosis, but the pupil, if affected, should be in mydriasis. And damage to the third cranial nerve should also produce some type of ophthalmoplegia, with diplopia. An involvement of the optic chiasm would produce a bilateral loss of vision (probably a bitemporal hemianopsia). We are told in the statement that he maintains good visual acuity. On the other hand, there would also be no ptosis or anisocoria. And finally, an alteration of the medulla oblongata would produce different neurological symptoms not described, and there should be no ptosis or pupillary alterations, because the third pair is located in the midbrain and the sympathetic nuclei in the spinal cord.
III cranial nerve.
Optic chiasm.
Upper cervical ganglion.
Spinal cord.
An alteration of the III cranial nerve can produce ptosis, but the pupil, if affected, should be in mydriasis.
An involvement of the optic chiasm would produce a bilateral loss of vision (probably a bitemporal hemianopsia). We are told in the statement that he maintains good visual acuity.
We should suspect an aneurysm. We should suspect a dissecting carotid aneurysm, which is one of the best known (and most serious) causes of an acquired Horner's syndrome. The superior cervical ganglion is a ganglion of the sympathetic nervous system located in the sheath of the carotid artery, and at this level it has been affected.
an alteration of the medulla oblongata would produce different neurological symptoms not described, and there should be no ptosis or pupillary alterations, because the third pair is located in the midbrain and the sympathetic nuclei in the spinal cord.