Lecture 5: 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
Which median nerve mononeuropathy is associated with an abnormal pinch sign w/ normal sensation?
Anterior Interosseous Syndrome
What is a common site in the elbow and wrist contributing to ulnar mononeuropathy?
- Elbow: between medial epicondyle and olecranon
- Wrist: Guyon’s canal