A 33-year-old woman comes to the office due to sensory loss in both upper extremities. She recently burned both of her hands while cooking but did not feel any pain. The patient has no history of trauma, headache, or neck pain. She also has no lower extremity weakness or abnormalities of bowel or bladder function. Examination shows diminished strength in the upper limbs. There is loss of pain and temperature sensation on the posterior neck, both shoulders, and both upper extremities. Vibratory and proprioceptive sensation are preserved. Which of the following is the most likely cause of this patient's symptoms?

Question

A 33-year-old woman comes to the office due to sensory loss in both upper extremities.  She recently burned both of her hands while cooking but did not feel any pain.  The patient has no history of trauma, headache, or neck pain.  She also has no lower extremity weakness or abnormalities of bowel or bladder function.  Examination shows diminished strength in the upper limbs.  There is loss of pain and temperature sensation on the posterior neck, both shoulders, and both upper extremities.  Vibratory and proprioceptive sensation are preserved.  Which of the following is the most likely cause of this patient's symptoms?

Quizplus · Accepted Answer

11ec25c8_d565_d440_bc81_8dbde5c2d377_MD0003_00 This patient likely has syringomyelia, a disorder in which a fluid-filled cavity (ie, syrinx) forms within the spinal cord. The syrinx may represent dilation of the central canal or a separate cavity within the spinal parenchyma and is usually located within the cervical or thoracic spine. Syringomyelia is most associated with Chiari type 1 malformation but may also occur with spinal cord inflammation, infection, neoplasms, or trauma. Patients frequently have loss of pain/temperature sensation in the dermatomes corresponding to the site of spinal involvement (eg, "cape" distribution). This is due to disturbance of the crossing spinothalamic tracts (STTs) in the anterior white commissure. In contrast, vibratory/proprioceptive sensation is typically intact due to preservation of the dorsal columns (ie, dissociated sensory loss). dermatomes Continued syrinx enlargement can encroach on the central aspect of the lateral corticospinal tracts (LCTs) (in which the upper extremity fibers are somatotopically arranged more centrally) and/or the anterior horn gray matter. This produces weakness that disproportionately affects the upper extremities compared with the lower extremities. Continued syrinx enlargement (Choice A) Degeneration of the dorsal and lateral spinal tracts (ie, subacute combined degeneration) can occur with vitamin B₁₂ deficiency. It typically causes impaired vibratory/proprioceptive sensation (with dorsal column involvement) and spastic muscle weakness (with LCT involvement). (Choice C) Ischemic injury of the anterior spinal cord causes anterior cord syndrome affecting the bilateral STTs and LCTs as well as the descending autonomic tracts involved in bladder control. Anterior cord syndrome typically results in loss of pain/temperature sensation and motor function below the level of spinal injury as well as urinary incontinence. anterior cord syndrome (Choice D) Segmental demyelination/inflammation of the spinal cord (ie, transverse myelitis), as can occur in multiple sclerosis, typically presents with rapidly progressive weakness and loss of all types of sensation (eg, pain/temperature, vibratory/proprioceptive) below the level of spinal injury. Bowel and bladder dysfunction, from disruption of autonomic tracts, is common. (Choice E) Cervical spondylosis (ie, degenerative changes of the cervical spine), which is common in elderly adults, may cause disc herniation or spinal cord compression resulting in radiculopathy and/or myelopathy. This patient's younger age and lack of neck pain make this diagnosis unlikely. Educational objective: Syringomyelia is a disorder in which a fluid-filled cavity forms within the spinal cord (usually within the cervical and/or thoracic spine). Patients typically have dissociated sensory loss (ie, loss of pain/temperature sensation but not vibratory/proprioceptive sensation), often in a "cape" distribution, and may develop weakness that disproportionately affects the upper extremities. References: Syringomyelia. (http://www.ncbi.nlm.nih.gov/pubmed/24272770) Prevalence of Chiari I malformation and syringomyelia. (http://www.ncbi.nlm.nih.gov/pubmed/26408058)

A 33-Year-Old Woman Comes to the Office Due to Sensory