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|QuestionAuthor={{Rim}} | |QuestionAuthor={{Rim}} | ||
|ExamType=USMLE Step 1 | |ExamType=USMLE Step 1 | ||
|MainCategory= | |MainCategory=Pathophysiology | ||
|MainCategory= | |SubCategory=Head and Neck, Neurology | ||
|MainCategory= | |MainCategory=Pathophysiology | ||
|MainCategory= | |SubCategory=Head and Neck, Neurology | ||
| | |MainCategory=Pathophysiology | ||
|MainCategory= | |SubCategory=Head and Neck, Neurology | ||
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|MainCategory= | |MainCategory=Pathophysiology | ||
|MainCategory= | |SubCategory=Head and Neck, Neurology | ||
| | |MainCategory=Pathophysiology | ||
|Prompt= | |SubCategory=Head and Neck, Neurology | ||
|MainCategory=Pathophysiology | |||
|SubCategory=Head and Neck, Neurology | |||
|MainCategory=Pathophysiology | |||
|SubCategory=Head and Neck, Neurology | |||
|MainCategory=Pathophysiology | |||
|MainCategory=Pathophysiology | |||
|SubCategory=Head and Neck, Neurology | |||
|Prompt=A 32 year old woman presents to the gynecology clinic for 3 months of absent menstruation. The patient has been trying to get pregnant for the past year but has been unsuccessful. She reports decreased libido and episodes of bilateral milky breast discharge. Which of the following visual field patterns is most likely present in this patient? | |||
|Explanation=[[Image:Optic_tracts_with_explanation.jpg|900px]] | |||
The patient has a typical presentation of [[hyperprolactinemia]] which is usually characterized by [[amenorrhea]], [[infertility]], decreased [[libido]], bilateral milky breast discharge, and [[osteoporosis]] if untreated. The most common cause of hyperprolactinemia is a pituitary tumor known as[[prolactinoma]]. As the prolactinoma enlarges it impinges on the [[optic chiasm]] leading to bitemporal hemianopia manifesting as loss of peripheral vision with patients complaining of bumping into objects and having difficulty with driving. | |||
Educational objective: Prolactinomas are prolactin secreting tumors of the pituitary that can enlarge to compress the underlying optic chiasm and cause bitemporal hemianopia. | |||
References: | |||
Jay WM. Visual field defects. Am Fam Physician. 1981;24(2):138-42. | |||
|AnswerA=[[Image:Visual1.gif]] | |||
|AnswerAExp=Homonymous hemianopia involves loss of vision on one side. It usually occurs due to a lesion to the optic tracts or a PCA stroke although the latter usually has associated macular sparing. This lesion is not seen with prolactinomas. | |||
|AnswerB=[[Image:Visual2.gif]] | |||
|AnswerBExp=Right upper quadrantopia is characterized by loss of vision in the right upper quadrant of the visual field. It usually occurs with left temporal lesions due to the interruption of the left Meyer's loop. Prolactinomas do not affect the temporal lobe. | |||
|AnswerC=[[Image:Visual3.gif]] | |||
|AnswerCExp=Left nasal hemianopia usually occurs with lesions of the internal carotid artery (internal carotid thrombosis) that occur lateral to the optic chiasm. This presentation is not typical of prolactinomas. | |||
|AnswerD=[[Image:Visual4.gif]] | |||
|AnswerDExp=This lesion portrays bitemporal hemianopia seen in large prolactinomas that abut the optic chiasm. | |||
|AnswerE=[[Image:Visual5.gif]] | |||
|AnswerEExp=Right lower quadrantopia is characterized by loss of vision in the right lower quadrant of the visual field. It usually occurs with left parietal lesions due to the interruption of the left dorsal optic radiations. Prolactinomas do not usually affect the parietal lobe. | |||
|RightAnswer=D | |||
|WBRKeyword=Bitemporal hemianopia, Prolactinoma, Visual field defects | |||
|Approved=No | |Approved=No | ||
}} | }} |
Revision as of 02:35, 6 October 2013
Author | [[PageAuthor::Rim Halaby, M.D. [1]]] |
---|---|
Exam Type | ExamType::USMLE Step 1 |
Main Category | MainCategory::Pathophysiology |
Sub Category | SubCategory::Head and Neck, SubCategory::Neurology |
Prompt | [[Prompt::A 32 year old woman presents to the gynecology clinic for 3 months of absent menstruation. The patient has been trying to get pregnant for the past year but has been unsuccessful. She reports decreased libido and episodes of bilateral milky breast discharge. Which of the following visual field patterns is most likely present in this patient?]] |
Answer A | [[AnswerA::![]() |
Answer A Explanation | AnswerAExp::Homonymous hemianopia involves loss of vision on one side. It usually occurs due to a lesion to the optic tracts or a PCA stroke although the latter usually has associated macular sparing. This lesion is not seen with prolactinomas. |
Answer B | [[AnswerB::![]() |
Answer B Explanation | [[AnswerBExp::Right upper quadrantopia is characterized by loss of vision in the right upper quadrant of the visual field. It usually occurs with left temporal lesions due to the interruption of the left Meyer's loop. Prolactinomas do not affect the temporal lobe.]] |
Answer C | [[AnswerC::![]() |
Answer C Explanation | AnswerCExp::Left nasal hemianopia usually occurs with lesions of the internal carotid artery (internal carotid thrombosis) that occur lateral to the optic chiasm. This presentation is not typical of prolactinomas. |
Answer D | [[AnswerD::![]() |
Answer D Explanation | AnswerDExp::This lesion portrays bitemporal hemianopia seen in large prolactinomas that abut the optic chiasm. |
Answer E | [[AnswerE::![]() |
Answer E Explanation | [[AnswerEExp::Right lower quadrantopia is characterized by loss of vision in the right lower quadrant of the visual field. It usually occurs with left parietal lesions due to the interruption of the left dorsal optic radiations. Prolactinomas do not usually affect the parietal lobe.]] |
Right Answer | RightAnswer::D |
Explanation | [[Explanation::File:Optic tracts with explanation.jpg
|
Approved | Approved::No |
Keyword | WBRKeyword::Bitemporal hemianopia, WBRKeyword::Prolactinoma, WBRKeyword::Visual field defects |
Linked Question | Linked:: |
Order in Linked Questions | LinkedOrder:: |