WBR0299
| Author | [[PageAuthor::Ogheneochuko Ajari, MB.BS, MS [1] (Reviewed by Alison Leibowitz)]] |
|---|---|
| Exam Type | ExamType::USMLE Step 1 |
| Main Category | MainCategory::Embryology |
| Sub Category | SubCategory::Neurology |
| Prompt | [[Prompt::A 30-year-old female presents to the ER with complaints of a worsening headache, leg weakness, difficulty with swallowing, and progressive numbness of both hands. Physical examination reveals a bilateral loss of pain and temperature sensation in the upper extremities, with preserved touch sensation. An MRI reveals hydrocephalus. Which of the following is the most likely cause of this patient’s symptoms?]] |
| Answer A | [[AnswerA::Ependymoma]] |
| Answer A Explanation | [[AnswerAExp::Ependymoma, an ependymal cell tumor, is most commonly found in the 4th ventricle. It can cause hydrocephalus but will not typically manifest with the bilateral loss of pain and temperature sensation and the preservation of touch sensation.]] |
| Answer B | [[AnswerB::Diabetic neuropathy]] |
| Answer B Explanation | [[AnswerBExp::Diabetic neuropathy is associated with a reduced ability to feel temperature or pain sensations, but not a complete loss of pain and temperature sensations.]] |
| Answer C | [[AnswerC::Meningioma]] |
| Answer C Explanation | [[AnswerCExp::Meningioma is associated with a progressive spastic weakness in legs, increased intracranial pressure, and focal seizures.]] |
| Answer D | [[AnswerD::Spinal muscular atrophy]] |
| Answer D Explanation | [[AnswerDExp::Spinal muscular atrophy is associated with muscle weakness, poor muscle tone, limpness, or a tendency to flop (the "floppy baby" syndrome).]] |
| Answer E | [[AnswerE::Syringomyelia]] |
| Answer E Explanation | AnswerEExp::See explanation |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::The patient in this scenario likely has communicating syringomyelia, manifesting in the path from the 4th ventricle to the central canal. A rapidly developing syrinx blocks the flow of cerebrospinal fluid (CSF) from the 4th ventricle to the central canal and the lower part of the cerebellum protrudes from its normal location in the back of the head into the cervical or neck portion of the spinal canal. A syrinx may develop in the cervical region of the spinal cord, interrupting the decussating spinothalamic fibers that mediate pain and temperature sensibility, resulting in the loss of these sensations, while the gentle touch, vibration, and position senses are preserved. The syrinx may extend into the medulla, producing a syringobulbia that could result in dysphagia. Educational Objective: Syringomyelia can manifest in the bilateral loss of pain and temperature sensations and the preservation of touch sensation. |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Hydrocephalus; Loss of temperature sensation; Loss of pain sensation |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |