T2 L13: Lower limb injuries and compression syndrome

Question 1

What is the difference in symptoms between cauda equina and conus medullaris syndrome?

Answer 1

CE more severe pain that is asymmetric. CM is bilateral

Both ankle and knee reflexes are reduced in CE but only ankle in CM

CM gives earlier bowel/bladder symptoms and more impaired sexual function

Question 2

What are some compressive causes of cauda equina and conus medullaris syndrome?

Answer 2

• Disc herniation
• Epidural abscess
• Spinal epidural haematoma
• Diskitis
• Tumour
• Spinal fracture

Question 3

What are some non-compressive causes of cauda equina and conus medullaris syndrome?

Answer 3

• Spinal cord infarction
• Spinal arteriovenous malformation
• Inflammatory conditions Eg. multiple sclerosis, chronic inflammatory demyelinating polyradiculopathy, sarcoidosis
• Infection Eg, HIV, VZV, CMV, HSV, EBV, Lyme, TB

Question 4

What is sciatica?

Answer 4

Nerve root entrapment especially L5 and S1

Pain may be felt in dermatome or myotome

Question 5

Where does the lateral cutaneous nerve branch off from?

Answer 5

Directly from the spinal cord

Question 6

How can you injure the sciatic nerve?

Answer 6

Isolated hip or pelvic/sacral fracture

Question 7

What can cause tibial nerve damage?

Answer 7

• Haemorrhage
• Bakers cyst
• Nerve tumour
• Entrapment

Question 8

Injury to which nerve can make it hard to stand on your toes?

Answer 8

The tibial nerve

Question 9

How can the common peroneal nerve be compressed?

Answer 9

• Tight plaster casts
• Leg crossing
• Prolonged squatting

Question 10

What are the common presentations of common peroneal nerve damage/compression?

Answer 10

Sensory loss
-Dorsum of foot and outer aspect of leg

Weakness
-Dorsiflexion and eversion of foot

Question 11

What are some causes of length dependent polyneuropathies?

Answer 11

Diabetes
Alcohol
B12 deficiency 
Chemotherapy
Idiopathic

Question 12

What is Guillain-barre syndrome?

Answer 12

A condition affecting nerves causing weakness and pain. It’s rapidly progressive

Causes demyelination

It’s a post-infectious inflammatory condition

Question 13

What are neuronopathies?

Answer 13

They affect the cells directly not the nerve itself

Question 14

What is polyradiculopathy?

Answer 14

Damage that affects multiple nerve roots

Caused by spinal stenosis, cancer, infection

Question 15

What is compartment syndrome?

Answer 15

An increase in pressure within the the compartment that causes compromised circulation and function of tissues

Question 16

What investigations are performed to look for compartment syndrome?

Answer 16

Creatine kinase
Myoglobinuria
Raised lactate