Peripheral neuropathies (Hon) Flashcards
Dermatome
SKIN are supplied by a single spinal root
Myotome
MUSCLE group supplied by a single spinal root
Sclerotome
Area of BONE supplied by a single spinal root
Radiculopathy definition
nerve root dysfunction
What are the most common levels involved in radiculopathy?
Cervical
C5-6 = C6 nerve compression
**C6-7 = C7 nerve compression
Lumbar
L4-5 = L5 nerve compression
L5-S1 = S1 nerve compression
Which nerve root is compressed if a patient is experiencing symptoms across the C6 and C7 dermatomes?
C7
Which nerve root is compressed if a patient is experiencing symptoms across the L5 and S1 dermatomes?
S1
the C5 spinal nerve root innervates which DTR?
biceps
the C7 spinal nerve root innervates which DTR?
triceps
the L4 spinal nerve root innervates which DTR?
patella
the S1 spinal nerve root innervates which DTR?
achilles
Suprascapular nerve
comes off early on the brachial plexus; pure C5 to the supraspinatus and infraspinatus muscles
Parsonage-Turner Syndrome
a brachial plexopathy syndrome of unknown etiology; patient will present with severe pain in the shoulder and days later have weakness and atrophy of muscles of the shoulder girdle (pain subsides); spontaneous recovery in 6-18 months but steroids are helpful
diffuse, symmetrical disease involving motor, sensory or both neurons
definition of peripheral neuropathy (polyneuropathy)
Mononeuropathy
a type of peripheral neuropathy where there is only a single nerve affected; there is a specific pattern of sensory loss and weakness only in specific muscle(s)
Polyneuropathy
a type of peripheral neuropathy where there is diffuse symmetrical motor, sensory or both deficit; there is a stocking/glove sensory loss; distal weakness and possible atrophy; with decreased reflexes
Dysesthesia
pain upon gentle touch
Hyperalgesia
lowered threshold of pain
Hyperpathia
pain threshold is elevated, but pain is excessively felt
paresthesias
pins and needles sensation
What are the typical lower motor neuron symptoms?
distal weakness, cramps, fasciculations (twitches), atrophy, decreased DTRs and hypotonia
What are the typical symptoms of sensory large fiber lesion?
positive: tingling, pins and needles and numbness
Negative: decreased vibration, decreased joint position sense, areflexia, ataxia and hypotonia
What are the typical symptoms of sensory small fiber lesion?
positive: burning and jabbing sensation
negative: decreased pain (pin prick) and temp
Compression of the median nerve presents with what major clinical features?
sensory loss, thenar atrophy with an abnormal pinch sign
Compression of the ulnar nerve presents with what major clinical features?
clawing of 4th and 5th fingers, hypothenar atrophy and variable sensory loss
Compression of the radial nerve presents with that major clinical features?
wrist drop, triceps involved and sensory loss
Carpal tunnel syndrome
compression of the median nerve at the wrist; presents with sensory loss, thenar atrophy with an abnormal pinch sign
Cubital tunnel syndrome
compression of the ulnar nerve at the elbow; presents with clawing of 4th and 5th fingers, hypothenar atrophy and variable sensory loss
Saturday night palsy
compression of the radial nerve at the spiral groove; commonly due to abnormal sleep postures; presents with wrist drop, triceps involved and sensory loss
the median nerve sensory distribution; medial palmar surface of lower forearm and palm, thenar eminence, thumb and adjacent two fingers
Pronator Syndrome
median nerve mononeuropathy; diffuse/dull ache at the proximal forearm; pain is exacerbated in the forced forearm pronation; absence of nocturnal awakening because of pain or numbness
Anterior Interosseous Syndrome
a median nerve mononeuropathy; inability to make the “ok” sign with your hand
What test would you suspect to be positive in a patient with an ulnar neuropathy?
Froment sign; inability to bend at PIP joint to hold a piece of paper
Anterior Interosseous Syndrome; a median nerve mononeuropathy; inability to make the “ok” sign with your hand
a positive Froment sign seen in Ulnar neuropathy; inability to bend at PIP joint to hold a piece of paper
Peroneal nerve compression has what major clinical features?
foot drop, weak evertors, sensory loss in dorsum of foot
What is the most common cause of acquired peripheral neuropathy?
diabetes mellitus
wrist drop seen in compression of the radial nerve at the spiral groove; commonly due to abnormal sleep postures
stocking-glove distribution seen in peripheral neuropathy; legs usually affected first and more severely than the arms
What vitamin deficiency can cause a polyneuropathy?
Vitamin B12 deficiency seen in subacute combined degeneration
spinal cord in B12 deficiency seen in subacute combined degeneration; a peripheral neuropathy
Romberg Maneuver test what?
proprioception
What do suspect to find on a skin biopsy in a patient with a small fiber polyneuropathy?
decreased epidermal nerve fiber density
Which cranial nerves are most at risk in a patient with diabetes mellitus?
**CN III
and CN VI and CN VII
What is the most common hereditary polyneuropathy?
Charcot-Marie-Tooth 1A (CMT 1A) aka Hereditary Motor & Sensory Neuropathies 1 (HMSN 1)
Charcot-Marie-Tooth 1A (CMT 1A) aka Hereditary Motor & Sensory Neuropathies 1 (HMSN 1)
most common hereditary polyneuropathy; demyelinating; AD and onset is typically 1st or 2nd decade; presents with difficulty walking or running (legs>arms); EMG shows slowing of motor nerve conduction velocities
What would the EMG show in a patient with CMT 1A/HMSN 1?
slowing of motor nerve conduction velocities; demyelinating
Charcot-Marie-Tooth 1A (CMT 1A) aka Hereditary Motor & Sensory Neuropathies 1 (HMSN 1) foot; high arched foot and hammer toes
Acute inflammatory demyelinating polyneuropathy (AIDP) aka Guillain-Barré syndrome (GBS)
an acquired demyelinating polyneuropathy; typically follows an illness, surgery or immunization or *** viral syndrome with EBV, mycoplasma pneumonia or campylobacter jejuni; patient will present with ascending motor paralysis; possible respiratory failure in these patients
A viral syndrome of which organisms are typically seen before Guillain-Barré syndrome (GBS)?
EBV, mycoplasma pneumonia or campylobacter jejuni
What are key laboratory findings in Guillain-Barré syndrome (GBS)?
CSF - albumin-cytologic dissociation (increased protein to normal cell count and normal glucose)
NCV’s - slow conduction velocity and focal conduction block with prolonged F-waves
What is the typical treatment for Guillain-Barré syndrome (GBS)?
Direct treatment with plasma exchange or IVIg (not steroids)
Miller-Fisher Syndrome
a variant of Guillain-Barré syndrome (GBS); will find GQ1b/GT1a antibodies; patient will present with ophthalmoplegia, ataxia, arreflexia, facial weakness, dysarthria and dysphagia
In which pathology would you find GQ1b/GT1a antibodies in a patients serum?
Miller-Fisher Syndrome; a variant of Guillain-Barré syndrome (GBS)
Chronic Inflammatory Demyelinating Polyneuropathy (CIDP)
an acquired demyelinating polyneuropathy similar to GBS but slower and more persistent >2 months; patient will have a history of progressive and relapsing with the typical treatment; 15% of cases will have IgM or IgG present
