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::Incorrect. Ependymoma is an ependymal cell tumor most commonly found in the 4th ventricle. It can cause hydrocephalus but would not present typically with bilateral loss of pain and temperature sensation and preservation of touch sensation |
| Answer B | [[AnswerB::Diabetic neuropathy]] |
| Answer B Explanation | AnswerBExp::Incorrect. Diabetic neuropathy is associated with reduced ability to feel temperature or pain sensations and not a complete loss of pain and temperature sensation |
| Answer C | [[AnswerC::Meningioma]] |
| Answer C Explanation | AnswerCExp::Incorrect. Meningioma is associated with progressive spastic weakness in legs, increased intracranial pressure and focal seizures |
| Answer D | [[AnswerD::Spinal muscular atrophy]] |
| Answer D Explanation | AnswerDExp::Incorrect. 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::Correct. See explanation |
| Right Answer | RightAnswer::E |
| Explanation | [[Explanation::The patient in this scenario likely has communicating syringomyelia, where there is a path from the 4th ventricle to the central canal. CSF flows from the 4th ventricle to the central canal and a syrinx develops very rapidly. The lower part of the cerebellum protrudes from its normal location in the back of the head in 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 light touch, vibration and position senses are preserved. The syrinx may extend into the medulla, producing a syringobulbia that could cause dysphagia.
Educational Objective Syringomyelia is associated with bilateral loss of pain and temperature sensations with preservation of touch sensation Reference: First AID for the USMLE Step 1 2011 Pg 127 |
| Approved | Approved::Yes |
| Keyword | WBRKeyword::Hydrocephalus; Loss of temperature sensation; Loss of pain sensation |
| Linked Question | Linked:: |
| Order in Linked Questions | LinkedOrder:: |