Neuroscience · Year 2 · from Neuroscience
Case 1: Syringomyelia - Dissociated Sensory Loss
Patient Presentation
Demographics: 35-year-old male
Chief Complaint: Burns on hands that he did not feel occurring
History of Present Illness: A 35-year-old construction worker presents after his wife noticed multiple burn marks on his hands that he was unaware of. He reports that over the past year, he has been unable to feel hot and cold temperatures in his hands and forearms. He has sustained several burns while cooking and working with hot materials without realizing it. He also reports neck pain and stiffness. Notably, he can still feel light touch and knows the position of his fingers. He denies weakness or gait problems.
Physical Examination:
- Vital signs: Normal
- Neurological:
- Mental status: Normal
- Cranial nerves: Intact
- Motor: 5/5 strength throughout; no atrophy; reflexes 2+ and symmetric
- Sensory examination:
- Pain and temperature: Absent in cape-like distribution (bilateral shoulders, arms, and hands to approximately T4 level)
- Light touch: Intact throughout
- Vibration and proprioception: Intact throughout
- Gait: Normal
Workup:
- MRI cervical and thoracic spine with and without contrast: Syrinx (fluid-filled cavity) extending from C4 to T2 within the central spinal cord; Chiari I malformation with 8 mm cerebellar tonsillar herniation below the foramen magnum
- Brain MRI: Chiari I malformation confirmed; no hydrocephalus
Diagnosis: Syringomyelia secondary to Chiari I malformation
Treatment:
- Neurosurgical consultation for Chiari decompression surgery
- Posterior fossa decompression with duraplasty performed
- Post-operative MRI at 6 months showed reduction in syrinx size
- Occupational therapy for sensory protection strategies
- Education on avoiding burns and injuries due to sensory loss
Clinical Pearl: Syringomyelia causes the classic "dissociated sensory loss" pattern because the syrinx cavity disrupts the crossing spinothalamic fibers in the anterior white commissure while sparing the posterior columns. The spinothalamic tract carries pain and temperature sensation, which crosses at the level of entry. Thus, patients lose pain and temperature sensation at the level of the syrinx while retaining light touch, vibration, and proprioception (carried by the intact posterior columns). The cape-like distribution reflects the cervical location of the syrinx affecting crossing fibers at those levels.