Nerve Lesions Flashcards
What info does the dorsal-column medial lemniscus (DCML) tract convey?
Proprioception, vibration and 2 point touch discrimination
Where does the DCML decussate?
Medulla
What info does the spinothalamic tract convey?
Pain and temperature (lateral) Crude touch (anterior)
Where does the spinothalamic tract decussate?
At level of entry of spinal cord/ 2 levels above
What info does the spinocerebellar tract convey?
Balance and coordination
Where does the spinocerebellar tract decussate?
Dorsal don’t, ventral double cross
Name the ascending spinal tracts (3)
DCML
Spinothalamic tract
Spinocerebellar tract
Name the descending spinal tracts (3)
Corticospinal tract
Rubrospinal tract
Tectospinal tract
What does the corticospinal tract do?
Majority of motor functions
Where does the corticospinal tract decussate?
Lateral at medulla
Anterior at level of exit on spinal cord
What does the rubrospinal tract do?
Rudimentary motor function
Where does the rubrospinal tract decussate?
Midbrain
What does the tectospinal tract do?
Reflex head/ eye responses
Where does the tectospinal tract decussate?
Midbrain
What is myelopathy?
Compression of the spinal cord
What is radiculopathy?
Compression of the nerve root ‘pinched nerve’
What are the symptoms of myelopathy? (4)
Progressive (increasingly weak, clumsy hands)
UMN leg signs
LMN arm signs
Incontinence, hesitancy + urgency are late features
What are the symptoms of radiculopathy? (4)
Pain/ electrical sensations in arms/fingers at level of compression
Numbness
LMN weakness
Eventual wasting of muscles innervated by affected root
What are the investigations for myelopathy and radiculopathy?
MRI urgent
What is the treatment for myelopathy & radiculopathy?
Surgical decompression and dexamethasone
What contralateral sign is present in Brown-Sequard syndrome?
Loss of pain and temperature sensation below lesion
What ipsilateral signs are present in Brown-Sequard syndrome? (2)
Weakness
Loss of proprioception and vibration sense
What sign is present at the level of the lesion in Brown-Sequard syndrome? (2)
Flaccid paralysis
Loss of all sensation
What are the causes of peripheral neuropathy? (5)
DAVID Diabetes Alcohol Vitamin deficiency (B12) Infective (GB) Drugs (isoniazid)
What are some of the risk factors for carpal tunnel syndrome? (4)
Pregnancy
Obesity
Hypothyroidism
Rheumatoid Arthritis
What are the symptoms of carpal tunnel syndrome? (3)
Pain + paresthesia in hand = wake and shake
Loss of sensation in palm, medial 3 1/2 fingers
Wasting of thenar eminence
What muscle in particular shows wasting in carpal tunnel syndrome?
Abductor pollicis brevis
In carpal tunnel syndrome, when are the pain and paresthesia worse?
Worse at night
How do you investigate for carpal tunnel syndrome? (2)
Phalen’s (flexing) test
Tinel’s (tapping) test
How do you treat carpal tunnel syndrome? (3)
Conservative: pain relief, splint at night
Hydrocortisone injection
Surgical decompression/ cut open flexor retinaculum
What are the nerve roots for the sciatic nerve?
L4 - S1
What are the causes of sciatica? (4)
Pelvic tumours
Fracture to pelvis/ femur
Disc prolapse
Osteoarthritis
What are the symptoms of sciatica? (3)
- Sensory loss or pain in back of thigh/ leg
- Foot drop
- Loss of sensation below the knee laterally
How would you investigate sciatica?
MRI urgent
How would you treat sciatica?
Conservative
What is the cauda equina?
Bundle of spinal nerves from the level of L1/2
What are the symptoms of cauda equina syndrome? (6)
- Lumbosacral pain
- Saddle anaesthesia
- Areflexia
- Fasciculations
- Loss of bowel/ bladder control
- Urinary retention
How would you investigate cauda equina syndrome? (2)
MRI spine
PR (rectal exam)
How would you treat cauda equina syndrome? (2)
Surgical decompression
High dose dexamethasone
What are the red flags to look out for in cauda equina syndrome? (6)
Bilateral sciatica Bilateral flaccid leg weakness Saddle anaesthesia Bladder + bowel dysfunction Erectile dysfunction Areflexia
What does damage to the right optic nerve cause?
Loss of vision in right eye
What does damage to the optic chiasm cause?
Bitemporal hemianopia
What does damage to the left optic tract cause
Right homonymous hemianopia
What does damage to Meyer’s loop on the left (left optic radiation) cause?
Right homonymous superior quadrantanopia
What does damage to Baum’s loop on the left (left optic radiation) cause?
Right homonymous inferior quadrantanopia
What are the clinical features of an oculomotor nerve palsy? (3)
- Tramp’s palsy (eye down + out)
- Fixed dilated pupil, doesn’t react to light
- Ptosis
What nerve is affected in Bell’s palsy?
Facial nerve (CN 7)
What are the clinical features of Bell’s palsy? (3)
- Drooping of mouth corner
- Inability to close eyelid
- Smooth, wrinkle-free forehead
How do you treat Bell’s palsy?
Steroid
In CN 9/ 10 lesion, where does the uvula deviate?
Uvula deviates AWAY from lesion
In CN 12 lesion, where does the tongue deviate?
Tongue deviated TOWARDS lesion
