Neurology Blueprint
PANCE/PANRE Review
Diseases of the
Peripheral Nerves
Complex Regional Pain
Syndrome (CRPS)
CRPS frequently begins after surgery, injury, vascular
event such as stroke.
Another name for CRPS reflex sympathetic dystrophy.
Two Types of CRPS:
1. Type I- corresponds with patients with CRPS
without a definable nerve lesion in represents most
clinical presentations.
2. Type II- refers to patients with CRPS where there is
a definable nerve lesion.
Complex Regional Pain
Syndrome (CRPS)
Three Stages of CRPS:
1. Stage 1-Occurs either after an event or without an
apparent cause. The patient develops pain in a limb.
The common symptoms are: burning, throbbing pain,
diffuse, uncomfortable achy, insensitivity to cold or
touch, localized edema.
2. Stage 2-is marked by a progression of soft tissue
edema, thickening of skin, and articular soft tissues.
There is muscle wasting, and the development of
brawny skin. This stage typically takes 3 to 6 months.
3. Stage 3- the third stage is most severe. It is
characterized my limitation of movement, contractures
of the digits, waxy trophic skin changes, and brittle
nails. The longer a patient is in Stage 3, the harder it
is to reverse the clinical course with any type of
intervention.
Complex Regional Pain
Syndrome (CRPS)
Using Laboratory & Diagnostic Studies:
-Plain radiographs, CT scans, and MRI may show late
findings of the disease.
-Plain radiographs often will show osteopenia
-MRI may show soft tissue edema, skin thickening, and
muscle atrophy
-CT scan may show areas of osteoporosis in a swiss
cheese appearance that is consistent with stage III.
Complex Regional Pain
Syndrome (CRPS)
Formulating Most Likely Diagnosis:
-Diagnosis of CRPS early is difficult do to lack of objective findings.
-Autonomic testing and scintigraphy may provide an early clue in the diagnosis. Radiographic
studies can be helpful later on in the diagnosis.
-The patients response to treatment often is the best diagnostic test.
-Differential diagnosis includes: Central nerve root impingement, Pancoast syndrome, vasculitis,
migratory osteolysis, arteriovenous fistula, progressive systemic sclerosis, thoracic outlet
syndrome, RA, peripheral neuropathy, venous thrombosis, diffuse atrophy, and angioedema.
Complex Regional Pain
Syndrome (CRPS)
Health Maintenance:
-Early mobilization may reduce the
risk of development of CRPS.
-Supplementation with Vitamin C has
been used as another preventive
measure in fractures for reducing the
risk of CRPS.
Complex Regional Pain
Syndrome (CRPS)
Clinical Intervention:
-Sympathetic regional nerve block used to be the hallmark for diagnosis of CRPS. It is no longer
considered the gold standard.
-Patients that have had physical and occupational therapy with CPRS had better pain control but no
difference in range of motion after one year.
-Cigarette smoking is a risk factor for CRPS so cessation is recommended.
-Other clinical interventions include: tender point injections, nerve stimulation and epidural
clonidine.
Complex Regional Pain
Syndrome (CRPS)
Pharmaceutical Therapeutics:
-Several medications have been show to be better than placebo in
clinical trials with CRPS. These medications include:
anticonvulsants, biphosphonates, oral glucocorticoids, and nasal
calcitonin
-Antidepressants are often effective in reducing neuropathic pain
-Guidelines developed for CRPS include treating with
antidepressant such as elavil, an anticonvulsant such as neurontin,
an NSAID, and opioids for those with severe pain.
-Other strategies that have been used include nerve blocks with
clondine and bretylium or lidocaine and labetolol combination.
Complex Regional Pain
Syndrome (CRPS)
Applying Basic Science Concepts:
-The pathogenesis of complex regional
pain syndrome is unclear, but is thought
to involve formation of a reflex arc after
an inciting event.
-the pain sensation response to Injury
may lead to increased sensitivity of
increased axons to epinephrine and other
substances released by local sympathetic
nerves.
Peripheral Neuropathies
History Taking & Performing Physical Exam:
-Peripheral neuropathy refers to generalized,
homogenous process affecting many peripheral
nerves, with the distal nerves are affected most
prominently. Tend to occur in a glove and
stocking distribution.
-Physical exam findings are dependent on type
if axonal or demyelinating.
-Patients with axonal neuropathy, motor exam
may disclose some wasting of intrinsic muscles
of the feet or lower leg. Distal loss of sensation
to pin prick, light touch, vibration cold, and
proprioception may occur. Reflexes may be
hypoactive.
Peripheral Neuropathies
-Generalized weakness is the usual
presentation for patients presenting with
fulminant polyneuropathy secondary to
demyelination process. Sensation is also
reduced. Vibratory and proprioception are
also out of proportion to loss of pin prick and
temperature sensation.
-Patients with axonal neuropathy tend to
present over year.
-Patients with inflammatory demyelinating
polyneuropathy are variable. Patients with
Guillain Barre Syndrome a 2-6 weeks
decline is followed by stabilization.
Peripheral Neuropathies
Using Laboratory & Diagnostic
Studies:
-EMG’s can be used to help diagnose
peripheral neuropathy but are only
needed if the symptoms are severe and
rapidly progressing or no clear etiology.
-Routine lab evaluation CBC, Thyroid
Panel, Folate, Vitamin B12 levels.
-Nerve biopsy is occasionally helpful for
diagnosing etiology of peripheral
neuropathy to determine if it is axonal or
demyelinating.
Peripheral Neuropathies
Formulating Most Likely Diagnosis:
-Differential diagnosis includes spinal
cord process, acute myopathy,
neuromuscular junction disease, or
central process may mimic GBS.
-Abnormal EMG have the highest
specificity in case of neuropathy. It
should not be used only. Patients
need EMG’s if there is no clear
etiology or when symptoms are severe
and rapidly progressive.
Peripheral Neuropathies
Health Maintenance:
-Patients that suffer from diabetic neuropathy need aggressive
management of the blood sugar and HgA1C
-Patients with hypothyroidism need to have thyroid replacement.
-Patients with Vitamin B12 and Folate Deficiencies need to have
that replaced.
-Patients with toxic exposure due to alcohol abuse or heavy
metals need to avoid contact with those substances.
Peripheral Neuropathies
Clinical Intervention:
-Reducing exposure to the exogenous or
endogenous toxin in the most important step
with axonal neuropathies.
-Patients with diabetic neuropathy need
aggressive management of their blood sugar.
-Thyroid replacement generally helps
neuropathy due to hypothyroidism
-The mainstays of treatment with patients with
demyelinating neuropathies with chronic
inflammatory peripheral neuropathy are IV
immunoglobulin, glucocorticoids, and plasma
exchange.
Peripheral Neuropathies
Pharmaceutical Therapeutics:
-Patients with painful neuropathy
have shown response to various
medications such as: neurontin,
tegretol, dilantin, topamax, baclofen,
lyrica, elavil, and cymbalta.
-Patients with break through pain are
sometimes given NSAIDS or Ultram.
Peripheral Neuropathies
Applying Basic Science Concepts:
-Peripheral neuropathy has a variety of causes: diabetes, alcohol abuse, HIV infection,
Charcot Marie Tooth Disease
-Diabetic peripheral neuropathy is most common and is predominantly axonal. The
mechanism that causes this is related to inflammatory, metabolic and ischemic effects.
-Other systemic disease cause peripheral neuropathies: amyloidosis, hypothyroidism,
Vitamin B12 and Folate deficiency, and Lyme Disease
-Many neuropathies are toxic such as due to chemotherapy, heavy metals, and alcohol
abuse.
-Some neuropathies can be environmental induced from vibration or even be idiopathic.