Work Up for Limb Weakness

Question 1

What is the most dangerous differential and how should it be investigated?
Acute onset or rapidly progressive paraparesis bilaterally.

Answer 1

1. Cord compression

2. Immobilise C-spine, urgent MRI (if no compression on MRI, consider spinal stroke)

Question 2

What should you investigate in this presentation?

Bilateral UMN signs, sensory level, sphincter disturbance.

Answer 2

1. Hypertonia, brisk reflexes, extensor plantars - arrange MRI
2. History cancer (post-radiation myelopathy), B12
3. MND if sensory features are absent and LMN signs are present

Question 3

If there are bilateral sensory symptoms in a peripheral neuropathy, what should you think of?

Answer 3

1. GBS if distal numbness/tingling is followed by rapidly ascending weakness
2. Slowly progressive limb weakness more marked distally with a glove and stocking pattern suggests sensorimotor peripheral neuropathy (e.g. chronic demyelinating polyneuropathy) - NCS to differentiate degeneration and demyelination, test HIV, fasting glucose, thiamine.

Question 4

What does bilateral muscle fatigability, diplopia, voice weakening, and difficulty chewing indicate and how should it be investigated?

Answer 4

1. Myasthenia Gravis

2. Bloods, CT to exclude thymoma

Question 5

What does bilateral proximal weakness/tenderness and a raised CK indicate and how should it be investigated?

Answer 5

1. Myositis

2. Stop statins, muscle biopsy, anti-Jo-1

Question 6

What could sudden onset unilateral limb weakness indicate and how would you investigate it?

Answer 6

1. If painful, vascular/orthopaedic causes - compare pulses, colour, temperature; CRT; X-ray; raised CK for compartment syndrome.
2. TIA/stroke - CT head
3. Todd’s paresis if preceded by a seizure

Question 7

What could unilateral seizures or a raised ICP indicate and how would you investigate it?

Answer 7

1. Brain pathology

2. CT/MRI brain

Question 8

What could a fever, unilateral limb weakness, and meningism indicate and how would you investigate it?

Answer 8

1. Meningoencephalitis

2. Blood cultures and empirical antibiotics/antivirals, CT and LP

Question 9

What could progressive/rapid unilateral UMN signs indicate?

Answer 9

1. Progressive suggests space-occupying lesion proximal to anterior horn cells
2. Rapid suggests vascular/inflammatory cause

Question 10

What is it called when there are unilateral signs referable to a single nerve root/nerve?

Answer 10

Radiculopathy