L12 - Disorders of Motor unit and Spinal cord pathways CLINICAL CASES

Question 1

36 y/o male. 
Falls of horse while riding. 
Sudden onset of weakness in both leg. 
Unable to feel below costal margin. 
Bladder retention. 
Spastic paraplegia. 
Sensory level to T1.

Answer 1

Cervical cord compression.

Question 2

54 y/o male. 
Wasting of both hands. 
Loss of sensation in both hands. 
Spastic paraparesis
Exam-dissociated sensory loss

Answer 2

Syringomyelia.
Dissociated sensory loss - loss of pain and temperature with preserved fine touch.
Cape distribution due to characteristic involvement of the spinal cord motor and sensory pathways.

Question 3

78 y/o female. 
Atrial fibrillation. 
Sudden onset of weakness in legs.
Loss of sensations with gradual improvement over next week. 
Preserved fine touch. 
Paraparesis.

Answer 3

Spinal cord stroke due to anterior spinal arery thrombosis.

Paraparesis - partial paralysis of the lower limbs.

Question 4

65 y/o banker.
Notices wasting of arm muscles, leg weakness, and spontaneous muscle twitching.
Spastic Paraparesis

Answer 4

Motor neuron disease.

• combination of upper and lower motor neuron signs
• no sensory signs
• face, extraocular muscles and sphincter spared.

Question 5

18 y/o , Tenerife holiday 
Severe diarrhoea on returning home 
Weak legs which came on gradually and worsened over 2 week. 
Bladder control retained 
LMN weakness in legs.

Answer 5

Guillain Barre syndrome.

• immune mediated damage to myelin in peripheral enrve foots.
• symptoms can progress up to 4 weeks after onset.

Question 6

18 y/o
Friday night, went to bed, had consumed alcohol and was high as fuck
Woke up 18hr later with foot drop and numbness over foot.
No back pain.
Left foot drop with loss of sensation

Answer 6

Pressure palsy of Peroneal nerve.

Risk factors - habitual leg crossing, prolonged positioning with pressure in this area.

Foot drop can also be due to lumbar root compression (L5,S1) which can affect plantar flexion and inversion in addition to foot dorsiflexion.

Question 7

65 y/o
Episodic droopiness of the eyelids with double vision.
Worse during latter part of day.
Slurring of speech after he talks.
Normal in clinic
DNA follow up appointment.
3 months later, admitted to ITU with resp muscle weakness.

Answer 7

Myasthenia Gravis

• classical clinical presentation with episodic extra ocular and bulbar weakness with fatiability.
• due to involvement of fast motor units which fatigue quickly.

Autoimmune disorder due to autoantibodies to ACH receptor.

Question 8

46 y/o 
Long term steroid use. 
Presents with weakness of shoulders and hips. 
Unable to get up from chair unassisted. 
Can't lift arm above shoulder. 
No muscle wasting, reflexes normal.

Answer 8

Proximal myopathy due to long term steroid use.

Myopathies cause proximal muscle weakness, sparing distal muscles.