Localising the lesion – where in the nervous system?

1. Localising the lesion – where in the nervous system? CRAIG HICKSON & Helga Magnusson

2. Aims and objectives Definitions of the CNS & PNS To learn the signs associated with LMN and UMN Brief recap on the functions associated with different lobes Cortical representation of body parts Circle of Willis and blood supply to each hemisphere Motor tracts – lateral corticospinal Sensory – lateral spinothalamic & dorsal column Clinic scenarios/Case vignettes

3. The central nervous system ‘The CNS consists of the ........ and the .............. Some definitions include the ..............and the retina ?

4. The peripheral nervous system ‘The PNS consists of the nerves and the ganglia outside of the brain and the spinal cord’ Includes autonomic NS and in most definitions the cranial nerves

5. Upper motor neuron signs Spastic paralysis Hypereflexia Hypertonia No muscle wasting – some wasting from lack of use eventually Pyramidal weakness – flexion of upper limbs, extension of lower limbs Positive Babinski – up-going plantar ?

6. Lower motor neuron signs Flaccid paralysis Hyporeflexia Hypotonia Muscle wasting Fasiculations Weakness of muscle groups – mytomes -ve Babinski?

7. Lobar function • Fontal – personality, executive function, cognition, & primary motor cortex. • Left Frontal – Broca’s area • Parietal – primary sensory cortex • Occipital – vision • Temporal – hearing • Left Temporal – Wernicke’s area • Cerebellum – balance, co-ordination • Basal ganglia – initiation, inhibition of movement

8. Homonculus Hands and face massively ‘over represented’ More sensitive

9. Circle of Willis Anterior cerebral artery Middle cerebral artery ? Posterior cerebral artery Basilar artery A = ? Vertebral artery Anterior spinal artery B = ?

10. Blood supply to the brain

11. The tracts ? Dorsal column Corticospinal ? ? Spinothalamic

12. Spinothalamic • Contra-lateral • Cross at entry level • pain and temp over 1 level • touch over several • Pain, Temperature, touch • ?

13. Dorsal Column • Contra-lateral • Cross at Medulla • Vibration, propriaception • Discriminative touch • ?

14. Corticospinal • Motor tracts • Contra-lateral • Cross at Medulla

15. How to think • UMN or LMN signs? • LMN: peripheralnerve/neuromuscularjunction/muscular. • UMN: cerebral (?lobe), cerebellar, spinal cord (?tract) • Can the symptoms be explained by one lesion? • Differential diagnosis: • Immediate: vascular. • Intermediate: inflammation/infection/malignancy. • Long term: degenerative/malignancy.

16. Cases • 57 year old man complaining of weakness and altered sensation in upper limbs and lower limbs • Loss of sensation from shoulders and down, urinary incontinence • ON Examination • CN intact • Upper limbs weakness, hypotonia, reduced reflexes • Lower limbs spasticity, hyper-reflexia and Babinski +ve, reduced sensation from shoulders down

17. What could have caused this picture?

18. Cases • 85 year old man with long standing (20yr) history of balance problems worse in the dark. • Gait is high stepping • ON Examination • CN intact • Motor intact • Loss of propriaception with +ve romberg

19. What could have caused this picture?

20. Cases • 35 year old lady who cant feel hot water when she puts her hand in the bath anymore • ON Examination • Sensation – pain and temp reduced in upper limbs • Light touch and propriaception retained

21. What could have caused this picture?

22. Cases • 42 year old lady complaining of unsteadiness of balance and slurred speech, she has noticed weakness and loss of sensation in her left leg • Leg symptoms have been present for two months • Unsteadiness and slurred speech came on over last 10 days • On examination: • CN intact • Weakness left lower limb 4/5 • Hyper-reflexia – left leg only • Coordination impaired on left • Mental state NAD

23. What could have caused this picture?

24. Thankyou for listening and contributing

25. Stroke syndromes • TACI • PACI • POCI • LACI