CNS Disorders: Tabes Dorsalis and Syringomyelia PDF

CNS Dr Nageeb Tabes dorsalis Definition: - It is one of the syphilitic manifestations in the CNS. Site of lesion: - Degeneration of the dorsal root fibers, central to dorsal root ganglia...

CNS Dr Nageeb Tabes dorsalis Definition: - It is one of the syphilitic manifestations in the CNS. Site of lesion: - Degeneration of the dorsal root fibers, central to dorsal root ganglia. - Occur usually in Lumbo-sacral segments (pantaloon area = Lower limbs). - But, thoracic or cervical segments may be affected. Characters: 1. At first: irritation of nerve fibers  sever pain in Lower limbs. 2. Then: fibrosis of nerve fibers  Loss of pain and all other sensations. 3. Loss of the proprioceptive sensations: Sensory ataxia: It is in-coordination of voluntary movements without muscle paralysis. Patient is unaware of his limbs  in-coordination of movements. Sensory ataxia is manifested by: a) Romberg sign: patient can only keep equilibrium by his eyes and if he closes them he falls immediately. (as during washing face). b) Stamping gait: because patient is unaware of his legs he tries during walking to feel the ground by hitting strongly on the earth. (High Steps & Strong Hitting). 4. Loss of all reflexes: a) Loss of superficial reflexes: as protective withdrawal reflex  makes the skin full of ulcers. b) Loss of deep reflexes: as stretch reflex  Atonia (loss of muscle tone). c) Loss of visceral reflexes:  Loss of micturition & defecation reflexes  Retention with over flow (Dribbling). Bladder becomes distended, thin walled and hypotonic.  Loss of erection reflex  impotence. Make it Easy 44 CNS Dr Nageeb Syringomyelia (Central Cord Syndrome) Definition: (Syringe = cavity & Myelia = spinal cord) - It is Cystic dilatation fluid (syrinx) of the Central Canal of spinal Cord leading to Cavity formation with pressure on the Crossing fibers spinothalamic tracts - It is due to syphilitic affection or abnormal proliferation of glial cells. - Gray matter around the central canal is the most affected part. So, the sensory disturbances are more pronounced than the motor disturbances. Site of lesion: - Occur usually in lower Cervical segments & upper thoracic (jacket area = upper limbs). Characters: - The lesion affects the Crossing fibers of lateral and ventral spinothalamic tracts  degeneration & Atrophy  leading to: 1. Loss of pain & temperature & rough touch sensations in both sides in affected region (Jacket shaped area). 2. Fine touch & proprioceptive sensations remains intact. - So it is called (dissociated jacket sensory loss). - There is flaccid paralysis of muscles if anterior gray horn is affected Make it Easy 45