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

Upper motor neuron lesions Pyramidal (Corticospinal tract) Extrapyramidal Babinski sign Spastic paralysis – increased muscular tone and hyperactive reflexes Absent superficial abdominal reflexes Little or no muscular atrophy Absent cremasteric reflex Exaggerated deep muscle reflexes Loss of performance of fine skilled voluntary movements Flapping clonus Hypertonia and clasp knife response In practice they occur together!

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

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.

Sensory & combined lesions Subacute combined degeneration of the cord Tabes Dorsalis Brown-Sequard syndrome Syringomyelia Spinal shock

Subacute combined degeneration of the cord Cause B12 deficiency (usually pernicious anaemia) Pathology Degeneration of the dorsal columns (myelin degeneration) Signs & symptoms • Legs, arms, trunk – progressive from tingling and numbness to weakness • Visual impairment • Change in mental state • BILATERAL spastic paresis/paralysis • Sensations diminished = pressure, vibration and touch Clinical tests • +ve Babinski sign = extensor plantar reflex • +ve Rhomberg test Treatment Reversible with B12 replacement if not been going on for too long

Tabes dorsalis Cause Untreated syphilis Pathology Degeneration of the dorsal columns (myelin degeneration) Signs & symptoms • Weakness, episodes of intense pain & disturbed sensation • Ataxia (tabetic gait), loss of coordination • Change in mental state e.g. dementia • Visual impairment • Sensations diminished = pressure, vibration and touch Clinical tests • +ve Rhomberg test Treatment IV Penicillin Analgesics Contact tracing! Tabetic gait = due to loss of proprioception, patient’s feet slap to the ground as they walk

Syringomyelia What is it? Enlarged cavity or cyst in the cervical/upper thoracic region of the cord Cause Congenital e.g. Arnold-Chiari malformation Tumours Trauma, haemorrhage Meningitis Signs & symptoms Abnormal or loss of sensations Chronic pain Usually spare dorsal columns – intact pressure, vibration, touch, proprioception May have ANS symptoms Clinical tests Cervical/Thoracic MRI Treatment Treat underlying causes Surgery to drain cysts

Brown-Séquard syndrome = hemisection of the cord Corticospinal tracts & dorsal columns decussate in the thalamus -> loss on same side Spinothalamic tracts decussate as soon as they go into the cord (or 1-2 levels above) -> loss on contralateral side Also loss of movements on the same side (corticospinal tracts – UMN signs below lesion, LMN signs at level of lesion)

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.

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

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

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

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

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)

Thank you!