Pupillary control Flashcards
A 32-year-old man is brought to the emergency department after a motor vehicle accident. He is unconscious, and his pupils are noted to be small and poorly reactive to light. Further examination shows no significant change in pupil size with exposure to bright light or darkness. Damage to which of the following structures is most likely responsible for this finding?
- A) Ciliary ganglion
- B) Pretectal nuclei
- C) Edinger-Westphal nucleus
- D) Optic chiasm
- E) Superior cervical ganglion
C
Explanation:
The Edinger-Westphal nucleus controls parasympathetic input for pupillary constriction. Damage to this nucleus results in poorly reactive, small pupils due to loss of parasympathetic tone, commonly seen in midbrain injuries.
A 45-year-old woman with multiple sclerosis reports blurry vision. A swinging flashlight test is performed, and when light is moved from the right eye to the left eye, both pupils dilate. When the light is moved back to the right eye, both pupils constrict normally. Which of the following is the most likely cause of this finding?
- A) Left optic nerve lesion
- B) Left oculomotor nerve palsy
- C) Left superior cervical ganglion dysfunction
- D) Left Edinger-Westphal nucleus damage
- E) Left ciliary ganglion lesion
Explanation: A
This describes a relative afferent pupillary defect (RAPD or Marcus Gunn pupil), caused by an optic nerve lesion. The affected eye transmits fewer light signals, leading to reduced pupillary constriction when the light is shined in that eye.
A 50-year-old man presents with right-sided ptosis, miosis, and anhidrosis. He has been experiencing chronic shoulder pain and weakness in his right arm for several months. A chest X-ray reveals a right lung mass at the apex. Which of the following structures is most likely affected?
- A) Edinger-Westphal nucleus
- B) Ciliary ganglion
- C) Superior cervical ganglion
- D) Oculomotor nucleus
- E) Optic tract
Explanation: C
This patient has Horner syndrome (ptosis, miosis, and anhidrosis), caused by disruption of sympathetic innervation. A Pancoast tumor at the lung apex can compress the superior cervical ganglion, disrupting sympathetic output.
A 23-year-old woman undergoes an eye exam for blurry vision. When light is shined in her right eye, both pupils constrict. However, when light is shined in her left eye, only the right pupil constricts. The right pupil remains reactive to light regardless of which eye is stimulated. Damage to which of the following structures best explains these findings?
- A) Left oculomotor nerve
- B) Left optic nerve
- C) Left pretectal nucleus
- D) Left ciliary ganglion
- E) Left Edinger-Westphal nucleus
E
Explanation:
The Edinger-Westphal nucleus is responsible for pupillary constriction. Damage to the left Edinger-Westphal nucleus prevents the left pupil from constricting, but the right pupil remains functional due to its intact parasympathetic innervation.
A 65-year-old man presents with sudden-onset right eye pain, headache, and blurry vision. He reports seeing halos around lights. Examination reveals a mid-dilated, non-reactive right pupil, and intraocular pressure is significantly elevated. Which of the following is the most likely diagnosis?
- A) Oculomotor nerve palsy
- B) Optic neuritis
- C) Acute angle-closure glaucoma
- D) Horner syndrome
- E) Adie pupil
CExplanation:
Acute angle-closure glaucoma presents with severe eye pain, a fixed mid-dilated pupil, and increased intraocular pressure. It occurs due to sudden blockage of aqueous humor outflow, leading to rapid pressure buildup.
C
A 27-year-old man presents with headaches and vision changes. Examination shows pupils that are small and irregular, but they constrict with accommodation but not in response to light. He has a history of an untreated sexually transmitted infection. Which of the following is the most likely diagnosis?
- A) Horner syndrome
- B) Adie pupil
- C) Argyll Robertson pupil
- D) Marcus Gunn pupil
- E) Oculomotor nerve palsy
A 40-year-old woman complains of intermittent blurry vision and difficulty focusing on near objects. Neurologic examination reveals a right pupil that is dilated and reacts sluggishly to both light and accommodation. Affected fibers originate from which of the following structures?
- A) Optic nerve
- B) Pretectal nucleus
- C) Ciliary ganglion
- D) Superior cervical ganglion
- E) Lateral geniculate nucleus
C
A tonic (Adie) pupil is dilated with a sluggish response to light and accommodation, often caused by damage to the ciliary ganglion, which provides parasympathetic innervation to the pupil.
A 30-year-old woman presents with right eyelid drooping and a fixed, dilated right pupil. She also has difficulty moving her right eye, which is deviated down and out. Which of the following additional findings is most likely present?
- A) Increased intraocular pressure
- B) Miosis and anhidrosis
- C) Impaired pupillary constriction in both eyes
- D) Ptosis due to levator palpebrae dysfunction
- E) Impaired corneal reflex
D
A 34-year-old man presents with right-sided ptosis and a constricted right pupil. There is also decreased sweating on the right side of his face. The neurologic deficit in this patient is most likely due to a lesion affecting which pathway?
- A) Sympathetic fibers traveling to the superior cervical ganglion
- B) Parasympathetic fibers in the oculomotor nerve
- C) The optic nerve
- D) The Edinger-Westphal nucleus
- E) The ciliary ganglion
A
A 72-year-old man with poorly controlled diabetes presents with acute-onset double vision. Examination reveals ptosis and a right eye that is “down and out.” Pupillary light reflex is intact. What is the most likely cause of this patient’s symptoms?
- A) Uncal herniation
- B) Pancoast tumor
- C) Ischemic damage to the oculomotor nerve
- D) Aneurysm of the posterior communicating artery
- E) Ciliary ganglion dysfunction
C
A 50-year-old woman is undergoing a pupillary exam. Light is shined into her right eye, causing bilateral pupillary constriction. However, when light is shined into her left eye, neither pupil constricts. Where is the lesion?
- A) Left optic nerve
- B) Left oculomotor nerve
- C) Left superior cervical ganglion
- D) Left Edinger-Westphal nucleus
- E) Left ciliary ganglion
A
- A 61-year-old woman is found to have an aneurysm at the junction of the posterior communicating artery and the internal carotid artery. Which of the following clinical findings would most likely result from this aneurysm?
- A) Ptosis and a fixed, dilated pupil
- B) Ptosis and miosis
- C) Anisocoria that worsens in bright light
- D) Bilateral small, irregular pupils
- E) Afferent pupillary defect
A
A 42-year-old woman presents with right-sided ptosis, miosis, and anhidrosis. Further evaluation reveals that the patient had undergone thyroidectomy for thyroid cancer two years ago. Which of the following best explains her condition?
- A) Iatrogenic injury to the sympathetic trunk
- B) Iatrogenic injury to the oculomotor nerve
- C) Damage to the Edinger-Westphal nucleus
- D) Bilateral pretectal nuclei damage
- E) Ischemic optic neuropathy
A
A 28-year-old man is brought to the emergency department after a head trauma. His pupils are fixed and dilated. Imaging shows a right-sided uncal herniation. Which structure is most likely compressed?
- A) Optic nerve
- B) Pretectal nuclei
- C) Ciliary ganglion
- D) Oculomotor nerve
- E) Superior cervical ganglion
D
A 35-year-old woman presents with photophobia and difficulty reading. Examination reveals a mid-dilated right pupil that reacts poorly to light but constricts with accommodation. Which of the following is the most likely diagnosis?
- A) Oculomotor nerve palsy
- B) Horner syndrome
- C) Adie pupil
- D) Argyll Robertson pupil
- E) Marcus Gunn pupil
C
21.3.2025
3.05AM
