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 Educational Objective: References: ]]
Approved	Approved::Yes
Keyword	WBRKeyword::Hydrocephalus; Loss of temperature sensation; Loss of pain sensation
Linked Question	Linked::
Order in Linked Questions	LinkedOrder::