Peripheral Neuropathy-Louie Flashcards
If someone goes into Dr. Louie’s clinic & might have peripheral neuropathy…what types of symptoms might they describe?
numbness tingling pain imbalance weakness **mainly in feet & legs, sometimes glove (hands)
Why do the feet experience peripheral neuropathy first?
b/c they have the longest nerves–more affected.
Hands are more rare, but still an issue of longer nerves
How might a patient describe numbness?
Feels like I’m walking on logs.
Feels like my sock is always bundled up in my shoe.
How might a pt describe tingling?
pins & needles feeling
How might a pt describe pain?
burning, shooting, electric pain
often patients experience allodynia (non-painful things are excruciating)
What might a patient complain of that tips you off that they have imbalance?
they may say that they feel dizzy & disoriented
you can ask-problem in head or feet. They’ll say feet.
Imbalance. They may have multiple falls & an unsteadiness of gait.
If someone complains of imbalance & you do the Romberg test…what might happen? What are you testing?
once they close their eyes & block their vision, their unsteadiness will probably get worse & they may fall.
not due to cerebellum problem, but proprioception.
What patterns will you see in patients who complain of weakness?
you will see the weakness more distally than proximally
they may have trouble gripping, doing fine motor things, opening jars
foot drop or tripping over feet (shoes worn out at toe)
problems writing
If someone has bulbar or cranial nerve problems…what will be some of their symptoms?
diplopia (problem w/ extraocular muscles)
ptosis
dysarthria/dysphagia
What are some of the possible sensory problems of a peripheral neuropathy patient?
loss of pinprick sensation in distal extremities
loss of temp in distribution
hypersensitivity
loss of proprioception
Describe Charcot foot.
this is seen in atrophy of muscles
high arch
contracted, curled hammer toes
atrophied calf muscle
What does muscle atrophy look like in a hand?
thenar compartment may look wasted away. There should be bulk b/w thumb & 2nd finger dorsally…from interosseus muscle. If this isn’t there–problem.
What is a fasciculation?
a small involuntary muscle contraction & relaxation
What are some of the motor features of peripheral neuropathy?
distal atrophy possible fasciculations weakness distally tremor absent or diminished deep tendon reflexes foot drop
Describe the pes cavus foot deformity.
high arch
fixed plantar flexion of the foot
What are the facial features that are sometimes seen with peripheral neuropathy?
diplopia dysconjugate gaze ptosis facial asymmetry tongue weakness pupillary abnormalities (autonomic involvement)
What are 2 of the main components of an EMG exam?
nerve conduction study
needle electorde exam
Review: what is the fcn of nodes of Ranvier? What creates these?
saltatory conduction
myelinaton creates these (faster conduction)
What are some ways to measure action potentials?
oscilloscope
reading electrode
reference electrode
T/F The more strength a muscle needs, the more motor units it recruits.
True.
What are the different components of the spikes you see in an EMG? In diseased muscle, what do you see?
see phase (below baseline)
turns (near peak)
diseased muscle: polyphasic (lots of turns)
muscle disease also includes lower amplitudes
SO…you have a patient whose peak ms is lower for the median nerve than the ulnar nerve. They also have a lower peak ms for their median nerve @ the wrist than from the elbow-wrist. What condition does this patient have?
this patient has carpal tunnel syndrome most likely
Decreased sensory or motor amplitudes may suggest what on a nerve conduction study?
axonal damage
Delayed or slowed distal latencies or slowed conduction velocities in a nerve conduction study may be suggestive of what?
a demyelinating disease
Why was Lance’s conduction velocities slower than expected?
b/c his hand was cold…something that often alters results.
Abnormal temporal dispersion (what broadens the peak) or a nerve conduction block may be suggestive of what?
a demyelinating disease
focal nerve impingement
F-responses or H-reflexes could be indicative of what?
demyelinating disease
radiculopathy
focal nerve compression
Abnormal temporal dispersion gets narrower/wider & has a smaller/larger amplitude as the readings move right.
wider & smaller amplitude
What is the name of the syndrome in which you have no myelin left?
Guillen Barre Syndrome
A decrease in amplitude on a nerve conduction study of greater than 50% is indicative of what? What might cause this?
indicative of a conduction block
could be from demyelination. Extreme: GB syndrome
A conduction block is an example of an extreme what?
an extreme abnormal temporal dispersion
When you hear and see a lot of insertional activity on the needle electrode exam…what are you thinking?
sign of muscle irritability
may indicate neuropathy or myopathy
What are some examples of abnormal spontaneous activity? What could this indicate?
Fibs or P-waves
seen in acute ongoing neuropathy or myopathy
When do you see myotonic discharges?
myotonic myopathies
When do you see complex repetitive discharges on needle electrode exam?
chronic neuropathy
Describe the motor units in denervated muscle.
motor units are high amplitude
polyphasic
decreased recruitment
Describe the motor units in myopathic muscle.
motor units are low amplitude
polyphasic
increased recruitment
What is EMG good for?
detecting & classifying peripheral neuropathy
diagnosis of major compressive mononeuropathies (CTS)
diagnosis of myopathy
diagnosis of severe radiculopathy
To detect a myopathy, what do you have to do?
do a needle exam
What are the 3 most common disorders this doc sees?
- CTS
- Ulnar Nerve Entrapment
- Peroneal Nerve problems
If a neuropathy isn’t treatable…what should you do as a doc?
Don’t send them home! Focus on supportive therapy.
With axonal neuropathy what do you see on EMG?
Absent sensory & motor amplitudes
Fibs & P-waves present
Decreased Recruitment of motor units
High Amplitude-polyphasic motor unit seen
What is the most common cause of neuropathy in the world? In the US?
World: Leprosy
US: Diabetes
What is the differential diagnosis of axonal neuropathy?
diabetic neuropathy
other metabolic neuropathies (sometimes from gastric bypass surgery)
vasculitic neuropathy
hereditary neuropathy
What are the diagnostic things you will see with demyelinating neuropathy?
delayed distal latencies slowed conduction velocities abnormal temporal dispersion conduction block absent F-waves Needle: more p waves decreased recruitment of motor units High amplitude & polyphasic motor units
What is the differential diagnosis of demyelinating neuropathy?
Guillain-Barre Syndrome
MGUS_related neuropathies
Toxic Neuropathies (glue sniffing)
Hereditary: Charcot Marie Tooth Syndrome
What are some of the symptoms of Charcot Marie Tooth Syndrome?
Charcot Foot
distal weakness
tingling
What do the studies usu show w/ compressive neuropathies?
decreased sensory amplitudes
decreased motor responses
EMG: fibs, p-waves, fasciculations
Motor unit potentials are large, polyphasic, decreased recruitment
What do you see with radiculopathies?
normal sensory conduction
decreased motor amplitudes
absent F-responses
EMG: fibs, p-waves; motor unit potentials are large, polyphasic with decreased recruitment
When people get nerve biopsies done…which nerve is often used? When it is clinically helpful?
sural nerve (near lateral malleolus, sensation to the outer foot) done w/ a little muscle biopsy, same day surgery Usefulness: vasculitic neuropathy, differentiating b/w axonal & demyelinating neuropathies.
What’s the deal with QSART?
a research tool
estimates thresholds for sensation
When is a skin punch biopsy done?
exclusively to confirm a small fiber neuropathy lesion
