PERIPHERAL NERVES Flashcards
____ bacterial toxin
acts directly on the membranes of the Schwarm cells near
the dorsal root ganglia and adjacent parts of motor and
sensory nerves
diphtheria
____ causes occlusion of
vasa nervorum, resulting in multifocal nerve infarction
polyarteritis nodosa
_____ protein
synthesis of dorsal root ganglion cells is blocked with
subsequent neuronal destruction
doxorubicin toxicity,
which combines with the axoplasm of the largest sensory
and motor nerves via sulfhydryl bonds
arsenic
____which damages the microtubular transport system.
vincristine
toxicity,
mechanism of histopathological reactions of peripheral nerves
segmental
demyelination, wallerian degeneration, and axonal degeneration
Focal degeneration of the
myelin sheath with sparing of the axon is called _______
segmental
demyelination.
a reaction of both the axon and
myelin distal to the site of disruption of an axon
wallerian degeneration
when the axon degenerates
as part of a “dying-back” phenomenon in a more
generalized metabolically determined polyneuropathy, it
is termed _____
axonal degeneration.
Certain diseases affect the neuron primarily rather
than the axon and cause either a motor or sensory _______.
neuronopathy
By means of ________, the cell bodies receive signals to
increase their metabolic activity and to produce growth
factors and other materials needed for axonal regeneration.
retrograde
axonal transport
These
retrograde changes consist of swelling of the cell cytoplasm
and marginalization and dissolution of the Nissl
substance. The important point again is that despite the
destructive changes in the nerve fibers, the nerve cells,
while altered in histologic appearance, are left intact with
preservation of the apparatus required for recovery.
chromatolysis
T or F
recovery is much slower with
wallerian or axonal degeneration, often requiring months
to a year or more
T
Recurrent demyelination and remyelination lead
to ________formations and enlargement of nerves,
the result of proliferating Schwarm cells and fibroblasts
that encircle the axon and its thin myelin sheath
“onion bulb”
Regenerating axon filaments take
aberrant courses and, with fibroblastic scar formation,
they may form a disorganized clump of tissue termed
_____
pseudoneuroma
This represents the “length-dependent” pattern that is
typical of ______. The nutritional, metabolic,
and toxic neuropathies assume this
axonal degeneratio
By contrast, in demyelinating polyneuropathies, the _______ of lesions and blockage of electrical conduction
often leads to weakness of proximal limb and facial muscles
before or at the same time as distal parts are affected
multifocal
nature
The maximum degree of denervation
atrophy after an acute injury to the axons occurs in _____ and reduces muscle volume by 75 to 80 percent.
90 to
120 days
Ultimately in muscle
atrophy, there is degeneration and loss of the denervated
muscle fibers. This process begins in _________months; in 3 to
4 years,
6 to 12
_______, in which tendon reflexes
may be retained, even with marked loss of perception
of painful stimuli.
small-fiber neuropathies
An ________pattern of sensory
loss over the abdomen and thorax in severe axonal neuropathy
may be mistaken for the sensory level of a spinal cord lesion.
“escutcheon”
Loss of proprioception may also give rise to small
wavering, fluctuating movements of the outstretched fingers–
called _______ or “dancing fingers.”
pseudoathetotic,
Austin pointed out that foot deformity is
found in ___ of patients with hereditary polyneuropathy,
and spine curvature is found in 20 percent
30 percent
Unequal weakening
of the paravertebral muscles on the two sides of the spine
during early development leads to ______
kyphoscoliosis
In an
anesthetic and immobile limb, the skin becomes tight and
shiny, the nails curved and ridged, and the subcutaneous
tissue thickened____
(“trophic changes”)
_________ two o f the most
frequent manifestations of autonomic failure, predominate
in certain types of polyneuropathies.
Anhidrosis and orthostatic hypotension,
In GBS
A mild respiratory or gastrointestinal infection or immunization
precedes the neuropathic symptoms by 1 to
3 weeks in approximately _____ percent of cases
60
______ is the most frequent identifiable
antecedent infection, but it accounts for only a relatively
limited proportion of cases
Campylobacter jejuni
viruses associated with GBS
(cytomegalovirus [CMV], Epstein-Barr virus
[EBV], HIV), and less often, bacterial infections other
than Campylobacter (Mycoplasma pneumoniae, Lyme disease
Only the______reflexes may be lost
during the first week of illness.
ankle
Urinary
retention occurs in approximately _____percent of patients
soon after the onset of weakness, but catheterization is
seldom required for more than a few days
15
rapid evolution
of polyneuropathy and slow and poor recovery.
muscle atrophy
became apparent relatively early in the axonal form
axonal
pathologic mechanism of Acute Axo n a l F o r m
complement and
the presence of macrophages in the periaxonal space, a
humoral antibody directed against some component of the
axolemma was postulated by
A proportion of axonal cases, perhaps up to one-fifth,
are associated with circulating antibodies to the ______
of peripheral nerve, and some of these reflect recently
preceding infection with C. jejuni
G M1 ganglioside
2 types of axonal
The acronyms AMAN
(acute motor) and AMSAN (acute motor-sensory axonal
neuropathy) are equivalents to axonal GBS.
prognosis of axonal
prolonged and incomplete recovery
what variant of GBS
causing difficulty
in swallowing with neck and proximal arm weakness
(Ropper, 1 986a) . Ptosis, often with ophthalmoplegia,
may be added.
plu!ryngeal-cervical-brachial
Ophthalmoplegia, whether occurring alone or
with weakness or ataxia of other parts, is almost uniformly
associated with a specific antineural antibody, ______
antiGQ1b.
CHON in CSF of GBS
The protein content is usually normal during the first few
days of illness, but then it rises, reaching a peak in ____
4 to
6 weeks
NCV findings in early GBS
- reduction in the amplitude of muscle action
potentials, - slowed conduction velocity, and
- conduction block in motor nerves
- Prolonged distal latencies and reduced distal amplitudes (reflecting distal conduction block) and
- prolonged or absent F responses (indicating involvement
of proximal parts of motor nerves and roots)
The acute motor axonal variety has a tendency to
be associated with antibodies to _____a and the
pharyngeal-cervical-brachial syndrome, to ______
GM1 or GD1
GTla.
pathologic findings in GBS
endoneural perivascular (mainly perivenous) lymphocytic infiltrates.
earliest change that could be detected
by Hafer-Macko and colleagues was the deposition of ___
complement on the inner layer of myelin.
______s early in their course, corresponding
in most instances to a predominantly motor presentation
and to axonal damage
antiGM1 antibodie
About ____
of our patients have required mechanical ventilation
one-quarter
A rough estimate of breathing capacity may be obtained
by having the patient count quickly on one deep breath.
The ability to reach 20 generally corresponds to a vital
capacity of greater than ____
1.5 L
the vital capacity
diminishes to below about ____endotracheal intubation
and mechanical ventilation are usually necessary
10 mL/kg,
Hypotension from dysautonomia, which occurs in
approximately ____ of paralyzed patients
10 percent
With tracheostomy and intensive
care, the mortality from the disease can be reduced to
approximately __
3 percent
In patients who are treated within 2 weeks with TPE,there
is an approximate
1.halving of the period of hospitalization,
- duration of mechanical ventilation, and of
the - time required to achieve independent ambulation
The most important predictors of responsiveness
to plasma exchange treatment are the same as for the
overall prognosis, namely:
the patient’s age (responders
are younger) and the preservation of motor compound
muscle action potential amplitudes prior to instituting
treatment
The advised regimen of plasma exchange removes a
total of_______ treatments
on alternate days, or over a shorter period if there is no
coagulopathy.
200 to 250 mL/ kg of plasma in 4 to 6
________
manifested most often by severe headache, are infrequent
complications of IVIg
Renal failure, proteinuria, and aseptic meningitis,
After the use of either plasma exchange or IVlg,
_____ of patients who initially improve will have
a relapse that becomes apparent several days or up to
3 weeks after completion of treatment.
5 to 10 percent
approximately _____ percent of
patients do not survive the illness, even in the best
equipped hospitals.
3 t o 5
In patients with respiratory failure, the average
period of machine-assisted respiration has been ___days
and the period of hospitalization approximately ___ day
22
50
An acute or subacute symmetrical polyneuropathy is a
frequent development in critically ill and septic patients,
particularly in those with failure of multiple organs
Critica l I l l n ess Po lyneu ro pathy
NCS of Acute U remic Po lyneu ro pathy
Electrophysiologic studies show
demyelinating features (slowing of conduction velocity),
but usually not a conduction block.
Local action of the exotoxin
may paralyze pharyngeal and laryngeal muscles (dysphagia,
nasal voice) within 1 or 2 weeks after the onset of
the infection and shortly thereafter may cause blurring of
vision because of paralysis of accommodation
D i p htheritic Polyneu ropathy
The important pathologic change of D i p htheritic Polyneu ropathy is one _______of spinal
roots, sensory ganglia, and adjacent spinal nerves
of segmental
demyelination without inflammatory reaction
Diphtheria antitoxin, given ___
of the onset of the infection, reduces the incidence and
severity of neuropathic complications
within 48 h
severe, rapidly advancing, more or less symmetrical
and mainly motor polyneuropathy-often with abdominal
pain, psychosis (delirium or confusion), and convulsions-
may be a manifestation ____
of acute intermittent
porphyria.
Both of these hepatic
forms of porphyria must be distinguished from the rarer
______ (congenital photosensitive) porphyria, in which
the nervous system is not affected.
erythropoietic
onset of porphyria
The first attack rarely
occurs before puberty, and the disease is most likely to
threaten life during adolescence and early adulthood
MC characteristics of porphyria
relapsing nature, acute onset,
abdominal pain, psychotic symptoms, predominant motor
neuropathy, often with an early bibrachial distribution
diagnosis of porphyria
large amounts of porphobilinogen and !1-aminolevulinic
acid in the urine
tx of porphyria
The use of intravenous glucose and intravenous
hematin (4 mg/kg daily for 3 to 14 days) is recommended
as the most effective therapy
______, when taken in sufficient amount, produce
a clinical picture resembling that of GBS or an acute
sensory polyneuropathy
Thallium salts
Thalium
The early onset of painful
paresthesias, sensory loss, and pain localized to joints,
back, and chest, as well as _______(after a week or
two), all serve to differentiate this neuropathy from GBS,
rapid loss of hair
Some cases of _______l polyneuropathy
may also develop acutely.
arsenical and possibly mercurial
In the Western world, nutritional polyneuropathy is usually
associated with_____
chronic alcoholism
In paraneoplastic polyneuropathy, ______polyneuropathy
has been 4 to 5 times more frequent than a purely sensory
one.
mixed sensorimotor
In paraneoplastic polyneuropathy,
destructive sensory neuropathy and neuronopathy
(ganglionitis) and are sometimes part of a more widespread
disorder of the nervous system related to the
______
anti-Hu antibody
The various forms of ______
are manifest clinically m 2 to 5 percent of patients with
malignant disease
paraneoplastic polyneuropathy
______ accounts for
approximately 50 percent of the cases of paraneoplastic
sensorimotor polyneuropathy and for 75 percent of those
with pure sensory neuropathy
Carcmoma of the lung
In patients who survive the ingestion of a single
massive dose of arsenic, a more rapidly evolving polyneuropathy
may appear after a period of___
8 to 21 days
Its most characteristic presentation is a motor mononeuropathy in the distribution of the radial nerves (wrist and finger drop).
Lea d N e u ropathy ( P l u m b i s m )
Pathology of Lead neuropathy
Axonal degeneration
with secondary myelin change and swelling and chromatolysis
of anterior horn cells has been described
In patients with
lower levels, doubling of the 24-h urinary lead excretion
following an infusion of the chelating agent CaNa2_______ indicates a significant
degree of lead intoxication
ethylenediaminetetraacetic
acid (EDTA)
a predominantly motor
polyneuropathy has been reported as a rare complication of
_______therapy for rheumatoid arthritis.
gold
takes the form of a myelopathy similar to that seen with
cobalamin deficiency
nitrous oxide
Both of these drugs cause a
dying-back polyneuropathy with axonal degeneration
and have been used experimentally to produce this effect
Triorthocresyl phosphate and acrylamide
_______are known to evoke
a dose-dependent, predominantly sensory polyneuropathy,
which begins several weeks after completion of
therapy in at least half of the patients
______sensation are most severely impaired
cisplatin, carboplatin, and bortezomib,
Proprioception and
vibratory
The taxanes______
both cited as inhibitors of the depolymerization of neurotubules,
are used mainly in the treatment of ovarian
cancer.
Pathologic studies have shown a
neuronopathy and distal axonopathy affecting mainly
______
paclitaxel and the more potent docetaxel,
large fibers
peripheral neuropathy
commonly complicates the use of _______ an
antineoplastic agent most widely used in treatment of
the lymphomas and leukemia.
vincristine,
Symptoms of neuropathy
appeared between 3 and 35 weeks after treatment was
begun and affected approximately 10 percent of patients
receiving therapeutic doses in the upper range
INH
The administration of____mg of pyridoxine
daily in conjunction with the isoniazid completely
prevents the neuropathy.
150 to 450
Paradoxically, the taking of
extremely high doses of pyridoxine over a prolonged period
may actually cause a disabling, predominantly ______
sensory
ganglionopathy
A predominantly
motor neuropathy has been reported with the
chronic administration of ______
dapsone,
____
used in the treatment of kala azar, may also induce a
purely sensory neuropathy with a propensity to affect the
trigeminal nerves.
Stilbamidine,
____, a drug used for treating
recalcitrant ventricular tachyarrhythmias, induces a
motor-sensory neuropathy in about 5 percent of patients
after several months of treatment. It may also cause a
toxic myopath
Amiodarone
Patients taking _____ to lower blood
cholesterol levels may experience distal and truncal
paresthesias, but an associated neuropathy has been
identified.
niacin
___ has long been known to cause a myopathy,
but a few cases of predominantly axonal sensory neuropathy
have also been reported (neuromyopathy).
Colchicine
Approximately ____percent of patients with diabetes
have symptoms and signs of polyneuropathy,
15
syndromes of DM polyneuropathy from:_________,
because of a diabetic microvasculopathy
ischemia or infarction of nerves or nerve fascicles
MC clinical syndrome of diabetic
neuropathy
distal, S1Jmmetrical, primarily sensory
MC nerves in Ac ute D i a bet i c M o n o n e u ro path i es
femoral, sciatic,
and peroneal nerves, in that order
The most characteristic syndrome affects the lumbar
roots. Pain, which can be severe, begins in the low back or
hip and spreads to the thigh and knee on one side; the discomfort
has a deep, aching character with superimposed
lancinating jabs and there is a propensity for pain to be
most severe at night. Weakness and later atrophy are evident
in the pelvic girdle and thigh muscles, although the
distal muscles of the leg may also be affecte`
diabetic amyotrophy,
in DM,
The pain is distributed over one
or several adjacent segments of the chest or abdomen;
it may be unilateral, or less often bilateral, and, as with
the lumbar radiculoplexopathy, sometimes follows a
period of recent weight los
thoracoabdominal radiculopathy
Occasionally, repeated
demyelination and remyelination lead to ____
formations of Schwann cells and fibroblasts, as it does in
the relapsing inflammatory neuropathies
onion-bulb
hyperglycemia inhibits sodium-dependent
_____ transport
Low levels of intraneural myoinositol
reduce phosphoinositide metabolism and ___
myoinositol
sodium-potassium adenosine triphosphatase (ATPase) activity
Another group of novel findings holds that there is a
reduction in trophic factors within diabetic nerves
(nerve
growth factor [NGF], vascular endothelial growth factor
[VEGF], erythropoietin);
experimental models of diabetic neuropathy,
the intramuscular administration of _____has had a
beneficial effect on several measures of nerve conduction
and on the histologic changes of diabetic nerve damage
in the treated limb
VEGF
acute or subacute involvement of multiple
individual nerves serially or almost simultaneously
MULTIFOCAL
POLYNEUROPATH I ES (MONONEUROPATHY,
OR MONONEURITIS MULTIPLEX)
More than half of all cases of mononeuropathy multiplex
can be traced to a systemic ___ involving the vasa
nervorum
vasculitis
Almost 75 percent o f cases o f polyarteritis nodosa include
involvement of the _____ of peripheral
nerves
small nutrient arteries
biopsy of PAN
Nerve biopsy, usually
taken from the sural nerve, will in most cases show the
necrotizing arteritis in _______(fibrinoid
necrosis of all 3 coats of the vessel walls), with infiltrating
eosinophils and occlusion of vessels
medium-size vessels
On the basis of the smaller
size of affected vessels and the presence of _______, Lhote
and colleagues have differentiated a “microscopic” polyarteritis.
perinuclear
antinuclear cytoplasmic autoantibodies (p-ANCA)
Based on the response to the systemic
vasculitides with ANCA activity, mononeuritis multiplex
caused by vasculitis has been treated with corticosteroids
and either
rituximab 375 mg/m2 weekly for 4 weeks, or
cyclophosphamide 1 g/m2 intravenously once a month
for several months
In PAN
For the corticosteroid regimen, we have
used intravenous methylprednisolone, ______ for
several days, followed by oral corticosteroid treatment.
1 .5 mg/kg,
A
characteristic feature is the excess of circulating and tissue
eosinophils (more so than in polyarteritis) and a tendency
of the vasculitis to involve the lungs and skin, in contrast
to the renal and bowel infarctions of polyarteritis nodosa
C h u rg-Stra uss a n d H y p e reos i n o p h i l ic Syn d ro m e
One
medication ______ that is used in Europe to treat
asthma has precipitated several cases of Churg-Strauss
disease.
(zafirlukast)
A granular
cytoplasmic pattern of _______ of the same type that occurs in
Wegener granulomatosis is found in more than half of
cases of churge strauss
antineutrophil cytoplasmic autoantibodies
c-ANCA
This process may b e associated with a vasculitic mononeuritis
multiplex as well as a more generalized polyneuropathy.
In many cases, glomerulonephritis, arthralgia,
and purpura are conjoined, reflecting the systemic nature
of the vasculopathy, but the mononeuritis may occur in
isolation.
These proteins can be detected
by cooling the serum and demonstrating a precipitation
of IgG and IgM proteins that redissolve upon warming
to 37°C (98.6°F) .
Essenti a l M i xed C ryog l o b u l i n e m i a
In RA,
The arteritis is of
_____ type and immune globulins are
demonstrable in the walls of vessels
small-vessel fibrinoid
Approximately ___ percent o f patients with lupus exhibit
symptoms and signs of peripheral nerve involvement
1 0
____ is another drug that has
been associated in rare instances with a vasculitis, including
mononeuropathies
Minocycline
Involvement of a single nerve with _____ most
often implicates the facial nerve (facial palsy), but
sometimes multiple cranial nerves
sarcoid
The triad of ____ is most characteristic of Lyme disease
during its disseminated phase, i.e., from 1 to 3 weeks
after the tick bite or from the appearance of the typical
rash.
cranial nerve palsies, radiculitis, and
aseptic meningitis
This
is perhaps the best characterized, but not the most common,
group of Lyme neuropathies. A painful lumbosacral
polyradiculitis has long been known in Europe by the
term ______
Bannwarth syndrome
Bannwarth syndrome from North American Lyme
under our care have progressed subacutely over days or
weeks and involved the ____
L2-L3-L4 roots
Treatment of the Lyme neuropathic
syndromes is with intravenous antibiotics, preferably
___
ceftriaxone 2 g daily for 1 month.
In HIV,
Almost unique and common patterns in
this group are the _____
and an acute or subacute painful infiltrative lymphocytic
neuropathy-the diffuse infiltrative lymphocytosis syndrome
CMV cauda equina neuritis syndrome
Po l y n e u ropathy Associ ated With
Pa r a p rote i n e m i a
The excess blood protein,
called a paraprotein or ______ is usually in the form of a
monoclonal immunoglobulin
“M-spike,”
The ______ affects mainly, but not exclusively, males in
the sixth and seventh decades of life. The onset is insidious
over weeks and months or more, with numbness and
paresthesias of the feet and then of the hands, followed
by a relatively symmetrical weakness and slight wasting
of these muscles. In some patients, sensory signs predominate.
The
CSF typically shows an elevation of the protein in the
range of 50 to 100 mg/ dL, and this is not due ______
polyneuropathy associated with monoclonal
gammopathy
to passive
diffusion of the excess paraprotein into the CSF
T or F
Despite the fact that IgG is the most frequent paraprotein
in adults, a polyneuropathy is associated somewhat
more often with the IgM class.
T
widespread polyradiculoneuropathies, usually with cytoalbuminologic
dissociation of the CSF (raised protein
concentration with few or no cells);
exhibit nerve conduction abnormalities characteristic of a demyelinating neuropathy (reduced conduction velocity and partialconduction block in motor nerves), and pathologically,
both show similar multifocal perivenous inflammatory
infiltrates
CIDP
diff of CIDP and GBS
- response to steroid
2. HLA expression
what defines CIDP
Chronic symmetric sensorimotor loss and areflexia
coupled with nerve conduction findings of demyelination
essentially defines the illness
NCV findings of CIDP
nerve conduction slowing to less than 80 percent
of normal values in several nerves; loss of late responses;
and dispersion of the compound muscle action potentials
Progression of CIDP
The clinical course was monophasic and slowly progressive in about one-third, stepwise and progressive in
another third, and relapsing in the remaining third.
2 subgroups of CIDP
relapsing (corresponding to the relapsing
and stepwise progressive cases of Dyck et al [1975])
and nonrelapsing ones
The CSF protein is elevated in
more than 80 percent of patients with CIDP, typically in
the range of _____. In rare instances there is
papilledema and a pseudotumor cerebri syndrome
75 to 250 mg/ dL
Infiltrates of CIDP
half are found to have
interstitial and perivascular infiltrates of inflammatory
cells, although one expects that most nerves would show
these changes if a sufficient number could be sampled
Tx of CIDP
Several trials have shown a short-term benefit from the intravenous infusion of high doses of gamma globulin (
In CIDP
found that plasma exchange
administered ________ had a beneficial
effect on both neurologic disability and nerve conducti
twice weekly for 3 weeks
