Peripheral neuropathies Flashcards
What is the distribution of peripheral neuropathy?
Glove and stocking
What are the causes of peripheral neuropathy?
ABCDE
A - alcohol
B - B12/folate deficiency
C - chronic renal failure
D - Diabetes, drugs
E - everything else - vasculitis, paraneoplastic
What nerve does cubital tunnel syndrome affect?
Ulnar nerve
Where does cubital tunnel syndrome affect?
Medial one and a half digits
How does alcohol contribute to peripheral neuropathy?
Causes thiamine deficiency
Which medication for TB may cause a peripheral neuropathy?
Isoniazid
Why does isoniazid cause a peripheral neuropathy?
It causes a B6 deficiency
What nerve causes carpal tunnel syndrome?
Median nerve
Where in the hand does the palmar branch of the median nerve supply?
Thumb
Index and middle finger
Lateral half of the ring finger
Which thenar muscles does the median nerve supply?
Abductor pollicis brevis
Opponens pollicis
Flexor pollicis brevis
What are the risk factors for carpal tunnel syndrome?
Obesity
Repetitive movements
Diabetes
Perimenopause
Rheumatoid arthritis
Hypothyroidism
Acromegaly
Trauma
What is the presentation of carpal tunnel syndrome?
Numbness
Paraesthesia
Burning sensation
Pain
Weakness of thumb movements
Weakness of grip strength
Difficulty with fine movements
Wasting of thenar muscles
What is Phalen’s test?
Fully flexing the wrists and holding them in this position - elicits numbness and paraesthesia in the median nerve distribution
What is Tinnel’s test?
Tapping the wrist at the location where the median nerve passes through the carpal tunnel - elicits numbness and paraesthesia in the median nerve distribution
What is the management of carpal tunnel syndrome?
Rest and altered activities
Wrist splints
Steroid injections
Carpal tunnel release surgery
What type of injury causes a common peroneal nerve palsy?
Injury at the neck of the fibula
What is the most common presentation of a common peroneal nerve lesion?
Foot drop
What are the other presentations of a common peroneal nerve lesion?
Weak dorsiflexion
Weak eversion of the foot
Weakness of extensor hallucis longis
Sensory loss over the dorsum of the foot
What drugs commonly cause peripheral neuropathies?
Amiodarone
Isoniazid
Vincristine
Nitrofurantoin
Metronidazole
What are the other causes of foot drop?
L5 radiculopathy
Sciatic nerve lesion
Superficial or deep peroneal nerve lesion
What symptoms does radial nerve damage cause?
Wrist drop
Sensory loss across the dorsal aspect of the 1st and 2nd metacarpals
