Neuro tract lesions

1. Neuro tract lesions Vivian & slides from ESA mentoring 2013

2. Upper motor neuron lesions In practice they occur together!

3. Lower motor neuron lesions • Flaccid paralysis • tone, focal muscle atrophy • Focal muscle weakness • or absent reflexes • Fasciculations

4. N.B. Lesions of the basal ganglia and cerebellum are also referred to as “extrapyramidal” but they are different to the UMN lesions – they don’t involve the descending motor tracts.

5. Sensory & combined lesions • Subacute combined degeneration of the cord • TabesDorsalis • Brown-Sequard syndrome • Syringomyelia • Spinal shock

6. Subacute combined degeneration of the cord

7. Tabesdorsalis

8. Syringomyelia

9. Brown-Séquardsyndrome= hemisection of the cord Also loss of movements on the same side (corticospinal tracts – UMN signs below lesion, LMN signs at level of lesion)

10. Spinal shock • Follows acute severe damage to the spinal cord. • <24 hours – 4 weeks • Depression or total loss of sensation and motor function below the level of the lesion. • Often associated with profound hypotension due to loss of sympathetic vasomotor tone.

11. How to approach a clinical case • Determine if there are any motor deficits • If yes what descending tracts are affected? • Is it pyramidal or extrapyramidal? • Is it an upper or lower motor neuron lesion? • Determine if there are any sensory deficits • If yes what ascending tracts are affected? • Determine if there are any cognitive problems • If yes then the damage probably has occurred in the brain? • What region effects the change in behaviour you have witnessed? • Where does the deficit start and end? • Torso/ limbs? • Dermatomes and myotomes are useful here • Is it sensory/ motor/ both & is the lesion central or peripheral? • What side of the body are they on? • Indicates side of lesion • Are the sensory and motor deficits on the same side? • Is the lesion above or below the level of decussation of the tracts involved

12. Case 1 • Pt presents with neck pain, paraesthesia in the medial side of the arm and hand, weakness affecting the whole hand and extension and abduction of the wrist joint. Bicep reflexes are normal but tricep reflex is absent. • Lower motor neuron (Weakness. Absent tricep reflex) • Neither pyramidal or extrapyramidal signs • Level of the common root of the spinal nerve as both sensory and motor signs

13. Case 2 • Pt presented with normal right arm and leg movement and minimal/ absent movement of left side with increased muscle tone and clasp knife rigidity. Pt had a flexor plantar reflex on the right and a babinski reflex on the left. Pt also had impaired facial movements on the left but with forehead sparing. • Upper motor neuron (increased muscle tone and clasp knife rigidity, babinski sign, forehead sparing) • Pyramidal and extrapyramidal signs • Most likely occurred in the brain because forehead sparing so needs to occur above pons

14. Case 3 • Pt presents with weakness in his left arm and hand. Has no sensory loss. Reduced grip on the left side with increased muscle tone. Biceps and brachioradialis jerks are exaggerated. Right side grip is also reduced and reflexes are brisk. • UMN (weakness with increased tone and reflexes) • Extrapyramidal • Lower brain stem or upper spinal cord small lesion as no sensory loss or corticospinal involvement

15. Case 4 • Pt presents with mild slurring of speech, blindness in right eye and tingling in the left side of her face, difficulty swallowing, weakness, numbness and hyperreflexia in the right leg with a babinski sign in the right foot • Both upper and lower • Both pyramidal and extrapyramidal • Multiple anatomically unrelated lesions (MS)

16. Thank you!