Sachen: Peripheral Neuropathies Flashcards
How can radiation injury vs. neoplastic etiology be differentiated on the basis of involvement and pain in terms of brachial plexopathy?
- Radiation injury: upper trunk, lateral cord, painless
- Neoplastic: medial cord, painful (breast and lung)
What are 6 motor signs/sx’s of peripheral nerve disease?
- Distal weakness
- Cramps
- Muscle fasciculations (twitching)
- Atrophy
- ↓ DTRs
- Reduced tone
What are sx’s of a small unmyelinated fiber neuropathy?
- Pain
- “Burning” dysesthesias
- Paresthesias
- Temperature sensation abnormalities
What will be seen on skin biopsy in a small (unmyelinated) fiber polyneuropathy?
↓ epidermal nerve fiber density
Weakness in shoulder abduction with loss of sensation in the lateral arm is seen with lesion of what nerve root?
C5
Weakness in shoulder abduction + elbow flexion with sensory loss in the 1st and 2nd digit is due to lesion of what nerve root?
C6
Sensory loss in the medial calf + weakness in hip flexion and knee extension is due to lesion of which nerve root?
L4
Sensory loss in the lateral calf/dorsum of foot + weakness in hamstrings + foot dorsiflexion, inversion, and eversion is due to lesion of what nerve root?
L5
What is the dermatomal distribution for T1?
Medial forearm
When diagnosing a plexopathy which 2 muscle can help identify proximal lesions?
- Rhomboids (Dorsal Scapular n. - C5)
- Serratus Anterior (Long thoracic n. - C5)
What are the negative vs. positive sx’s associated with a large (myelinated) fiber peripheral neuropathy?
- Negative: ↓ vibration + ↓ joint position sense + arreflexia + ataxia + hypotonia
- Positive: tingling + pins and needles + numbness
Which median mononeuropathy is associated with an insidious onset of diffuse/dull ache about th proximal forearm (rarely acute or sharp)?
Pronator Syndrome
Pronator syndrome will have associated sensory loss where in the hand?
Diffuse numbness of hand, mostly 2nd-3rd fingers (median n)
Which mononeuropathy is associated with an abnormal pinch (ok) sign w/ normal sensation?
Anterior Interosseous Syndrome (median n)
What is a common site in the elbow and wrist contributing to ulnar mononeuropathy?
- Elbow: cubital tunnel (medial epicondyle and olecranon)
- Wrist: Guyon’s canal
Which muscle and motion of the thumb will be impaired in ulnar mononeuropathy?
ADductor policis = weak thumb ADduction = Froment Sign
What is the most common site for radial mononeuropathy to develop; presents with what deficit?
- Spiral groove of the humerus == Saturday night palsy
- Presents with wrist drop due to paresis of extensor ms. of the wrist, finger, and thumb
- Elbow extension is SPARED!
What is Parsonage-Turner syndrome?
Autoimmune with severe shoulder pain for days that leads to weakness and atrophy
Spontaneous recovery in 6-18mo
3rd digit sensory loss, elbow/wrist/finger ext, and tricep reflex loss describes compression of which nerve root?
C7
Sensory loss to the 4/5th digit & loss of finger abd/flexion describes which nerve root loss?
C8
Sensory loss of the post/lat calf & loss of hamstrings/planterflexion describes loss of which nerve root?
S1
What nerves does the posterior cord give off? Lateral?
Posterior cord = axillary & radial
Lateral cord = musculocutaneous & median
What are the 3 locations assc w radial n neuropathy?
What are the motor/sensory impairments?
Motor = wrist drop; Sensoey = dorsum of hand
Locations
- Axilla: crutches
- Spiral groove: saturday night palsy
- Posterior interosseous: elbow synovitis
Which neuropathy is assc w thenar atrophy?
