Tabes Dorsalis Overview

Tabes Dorsalis

• Definition: One syphilitic manifestation in the central nervous system (CNS).
• Site of Lesion: Degeneration of dorsal root fibers, central to dorsal root ganglia, typically affecting the lumbar-sacral segments (lower limbs), but can also impact thoracic or cervical segments.
• Characteristics:
  • Initial Stage: Irritation of nerve fibers causing severe pain in lower limbs.
  • Later Stage: Fibrosis of nerve fibers resulting in loss of pain and other sensations (including proprioceptive sensations).
  • Sensory Ataxia: Impaired coordination of voluntary movements without muscle paralysis. Patients are unaware of their limb positions, leading to uncoordinated movements. Specific symptoms include:
    • Romberg Sign: Inability to maintain balance with eyes closed.
    • Stamping Gait: Patients attempt to feel the ground with strong steps, as they are unaware of their limbs' position.
• Loss of All Reflexes:
  • Loss of superficial reflexes (e.g., protective withdrawal reflex).
  • Loss of deep reflexes (e.g., stretch reflex), resulting in muscle atonia (loss of muscle tone).
  • Loss of visceral reflexes (e.g., micturition and defecation reflexes), leading to bladder retention (often with overflow dribbling). Impotence may also occur.

Syringomyelia (Central Cord Syndrome)

• Definition: A cystic dilation (syrinx) in the central canal of the spinal cord, resulting from fluid buildup and pressure on crossing fibers (especially spinothalamic tracts). It can be caused by syphilitic affection or abnormal glial cell proliferation.
• Site of Lesion: The central gray matter around the central canal is typically affected, typically in the lower cervical and upper thoracic segments (jacket area of upper limbs).
• Characteristics:
  • Sensory Loss: Degeneration and atrophy of spinothalamic tracts, causing loss of pain, temperature, and rough touch sensation bilaterally in affected regions (jacket-shaped area).
  • Preserved Sensation: Fine touch and proprioceptive sensations remain intact.
  • Dissociated Sensory Loss: This characteristic combination of sensory losses and preservations, is why this condition is called.
• Motor Involvement: Flaccid paralysis can occur if the anterior gray horn is affected.

Explore the clinical manifestations and stages of Tabes Dorsalis, a neurologic condition resulting from syphilis. This quiz covers the characteristics, sensory deficits, and symptoms such as ataxia and the Romberg sign. Understand the implications of nerve degeneration and its effects on coordination.