005 Diseases of the peripheral nervous system ppt.pptx
1. Diseases of the PNS
Dechasa Imiru, MSc PT
Physiotherapy Department
Institute of Health
Jimma University
June, 2023
6/7/2023 PNS 1
2. Introduction
―The PNS is classified into different types of
nerves, based on diameter, myelin sheet and
conduction velocity.
― Aα- and Aβ-fibers are classified as large nerve
fibers and Aδ- and C-fibers are classified as small
nerve fibers.
―Small myelinated Aδ-fibers show faster
conduction velocities (4–36m/s) compared to
unmyelinated C-fibers (0.4–2.8m/s) due to larger
diameter and myelin.
6/7/2023 PNS 2
3. Introduction
– Peripheral nerves are composed of sensory, motor, and
autonomic elements.
– Diseases can affect the cell body of a neuron or its
peripheral processes, namely the axons or the encasing
myelin sheaths.
– Most peripheral nerves are mixed and contain sensory and
motor as well as autonomic fibers.
– Nerves can be subdivided into three major classes: large
myelinated, small myelinated, and small unmyelinated.
6/7/2023 PNS 3
4. Introduction….
Motor axons are usually large myelinated fibers that
conduct rapidly (approximately 50 m/s).
– Sensory fibers may be any of the three types.
Large-diameter sensory fibers conduct proprioception
and vibratory sensation to the brain,
The smaller-diameter myelinated and unmyelinated
fibers transmit pain and temperature sensation.
– Autonomic nerves are also small in diameter.
6/7/2023 PNS 4
5. Introduction….
– Thus, peripheral neuropathies can impair sensory, motor, or
autonomic function, either separately or mixture.
– Peripheral neuropathies are further classified into those that
Primarily affect the cell body; Neuronopathy or
Ganglionopathy
Myelin; Myelinopathy
The axon; Axonopathy
– These different classes of peripheral neuropathies have distinct
clinical and electrophysiological features
6/7/2023 PNS 5
6. Introduction….
Peripheral neuropathies could occur in one
nerve, multiple nerves, diffuse fiber
involvement or nerve root.
– Mononeuropathy Multiplex
– Polyneuropathy Plexopathy
– MOTOR NEURON Ds RADICULOPATHY
6/7/2023 PNS 6
7. General approach
– In approaching a patient with a neuropathy, the
clinician has three main goals:
Identify where the lesion is,
Identify the cause, and
Determine the proper treatment.
– The first goal is accomplished by obtaining a
thorough history, neurologic examination, and
electro diagnostic and other laboratory studies.
6/7/2023 PNS 7
8. General approach…..
– While gathering this information, seven key questions
are asked, the answers to which can usually identify the
category of pathology that is present.
– Despite an extensive evaluation, in approximately half
of patients no etiology is ever found;
– These patients typically have a predominately sensory
poly-neuropathy and have been labeled as having
idiopathic or cryptogenic sensory polyneuropathy
6/7/2023 PNS 8
9. 1. What system is predominantly affected
Motor, sensory, autonomic or combinations?
– It is important to determine if the patient's symptoms
and signs are motor, sensory, autonomic, or etc
If the patient has only weakness without any evidence of
sensory or autonomic dysfunction, a motor neuropathy,
neuromuscular junction abnormality, or myopathy should be
considered.
Symptoms of autonomic involvement include fainting spells
or orthostatic lightheadedness; heat intolerance; or any
bowel, bladder, or sexual dysfunction
The majority of neuropathies are predominantly sensory in
nature
6/7/2023 PNS 9
10. 2. What is the distribution of weakness
Proximal, distal or both? Symmetric or Asymmetric?
– Outlining the pattern of weakness, if present, is
essential for diagnosis, and in this regard two
additional questions should be answered:
Does the weakness only involve the distal extremity
or is it both proximal and distal?
Is the weakness focal and asymmetric or is it
symmetric?
6/7/2023 PNS 10
11. ……distribution….?
Symmetric proximal and distal weakness is the
hallmark of acquired immune demyelinating
polyneuropathies, both
• The acute form (acute inflammatory demyelinating
polyneuropathy (AIDP) also known as GBS) and
• The chronic form (chronic inflammatory demyelinating
polyneuropathy (CIDP)).
6/7/2023 PNS 11
12. …..distribution……?
Findings of an asymmetric or multifocal pattern of weakness
narrows the differential diagnosis.
• The absence of sensory symptoms and signs, such
weakness evolving over weeks or months would be
worrisome for motor neuron disease (e.g., amyotrophic
lateral sclerosis (ALS)),
• but it would be important to exclude multifocal motor
neuropathy that may be treatable.
• Patient presenting with asymmetric sub acute or acute
sensory and motor symptoms and signs,
radiculopathies,
plexopathies,
compressive mononeuropathies, or
multiple mononeuropathies must be considered.
6/7/2023 PNS 12
13. 3. What is the nature of sensory involvement?
Small fiber involvement or large fiber involvement?
– The patient may have loss of sensation (numbness),
altered sensation to touch (hyperpathia or allodynia),
or uncomfortable spontaneous sensations (tingling,
burning, or aching).
– Neuropathic pain can be
• Burning, dull, and poorly localized (protopathic pain),
presumably transmitted by polymodal C nociceptor fibers,
or
• Sharp and lancinating (epicritic pain), relayed by A-delta
fibers.
6/7/2023 PNS 13
Allodynia is defined as "pain due to a stimulus that does not
normally provoke pain."
14. ……sensory…..?
If pain and temperature perception are lost, while
vibratory and position sense are preserved along with
muscle strength, deep tendon reflexes, and normal
nerve conduction studies, a small-fiber neuropathy.
– The most likely cause of small-fiber neuropathies,
when one is identified, is Diabetes mellitus or
glucose intolerance.
– but most of these small-fiber neuropathies remain
idiopathic in nature despite extensive evaluation.
6/7/2023 PNS 14
15. ……sensory…..?
– Severe proprioceptive loss also narrows the
differential diagnosis.
– Affected patients will note imbalance, especially in the
dark.
– A neurologic examination revealing a dramatic loss of
proprioception with vibration loss and normal strength
should alert the clinician to consider a sensory
neuronopathy/ganglionopathy.
6/7/2023 PNS 15
16. 4. Is there UMNL?
With sensory loss or without sensory loss?
– If the patient presents with symmetric distal sensory
symptoms and signs suggestive of a distal sensory
neuropathy,
– but if there is additional evidence of symmetric
upper motor neuron involvement, the physician
should consider a disorder such as combined system
degeneration with neuropathy – VitB12 deficiency
– Motor neuron disease should be considered if only
motor involvement occurs with combined UMNL
and LMNL
6/7/2023 PNS 16
17. 5. What is the temporal course?
– It is important to determine the onset, duration, and
evolution of symptoms and signs.
• Does the disease have an acute (days to 4 weeks),
sub acute (4–8 weeks), or chronic (>8 weeks)
course?
• Most PN are chronic in nature
– Is the course monophasic, progressive, or relapsing?
• Vasculitis and immune mediated PN causes a
relapsing course
6/7/2023 PNS 17
18. 6. Is there hereditary nature?
In patients with slowly progressive distal weakness over
many years with very little in the way of sensory symptoms
yet with significant sensory deficits on clinical examination,
the clinician should consider a hereditary neuropathy – CMT,
HSNPP
– On examination, the feet may show arch and toe
abnormalities (high or flat arches, hammertoes); scoliosis
may be present.
– In suspected cases, it may be necessary to perform both
neurologic and electro physiologic studies on family
members in addition to the patient.
6/7/2023 PNS 18
19. 7. Any other medical illness?
It is important to inquire about associated
Medical conditions: e.g., DM, SLE, thyroid diseases
Preceding or concurrent infections: e.g. diarrheal
illness - GBS
Surgeries (e.g., gastric bypass and nutritional
neuropathies);
Medications (toxic neuropathy) including over-the-
counter vitamin preparations (B6);
Alcohol and dietary habits;
Use of dentures: e.g., fixatives contain zinc that can
lead to copper deficiency).
6/7/2023 PNS 19
20. Pattern recognition approach
– Based upon the answers to the seven key questions,
neuropathic disorders can be classified into several
patterns based on the distribution or pattern of
sensory, motor, and autonomic involvement.
– Each pattern has a limited differential diagnosis.
– A final diagnosis is established by utilizing other clues
such as the temporal course, presence of other disease
states, family history, and information from
laboratory studies.
6/7/2023 PNS 20
21. Patterns….
Pattern 1
Symmetric proximal and
distal weakness with
sensory loss
– Consider: IDPN
Acute – AIDP (GBS)
Chronic – CIDP
Pattern 2
Symmetric distal sensory
loss with or without
distal weakness
– Consider:
Diabetes mellitus and
other metabolic
disorders,
Drugs, toxins,
Hereditary (CMT)
CSPN
6/7/2023 PNS 21
22. Patterns…..
Pattern 3
Asymmetric distal weakness
with sensory loss
A. With involvement of
multiple nerves
– Consider:
Multifocal CIDP,
Vasculitis, sarcoid
Infectious (leprosy,CMV,
hepatitis B or C, HIV,
HSNPP
Tumor infiltration
Pattern 3
Asymmetric distal weakness with
sensory loss
B. With involvement of single
nerves/regions
– Consider:
May be any of the above
Compressive mononeuropathy,
plexopathy, or radiculopathy
6/7/2023 PNS 22
23. Patterns……
Pattern 4
Asymmetric proximal and
distal weakness with
sensory loss
– Consider:
Polyradiculopathy or
Plexopathy due to DM
Meningeal carcinomatosis
Hereditary plexopathy
(HNPP, HNA),
Idiopathic
Pattern 5
Asymmetric distal weakness
without sensory loss
A. With upper motor neuron
findings
– Consider: MND
B. Without upper motor neuron
findings
– Consider:
Progressive muscular atrophy,
Multifocal motor neuropathy,
6/7/2023 PNS 23
24. Patterns….
Pattern 6
Symmetric sensory loss and
distal areflexia with upper
motor neuron findings
– Consider:
Vitamin B12, Vitamin E,
and copper deficiency with
combined system
degeneration with
peripheral neuropathy,
Hereditary
leukodystrophies
Pattern 7
Symmetric weakness without
sensory loss
A. With proximal and
distal weakness
– Consider: Spinal muscular
atrophy
B. With distal weakness
– Consider: Hereditary motor
neuropathy
("distal" SMA) or
atypical CMT
6/7/2023 PNS 24
25. Patterns….
Pattern 8: Asymmetric proprioceptive sensory loss
without weakness
– Consider causes of a sensory neuronopathy
(ganglionopathy):
Cancer (para-neoplastic)
Sjögren syndrome (dry eye and dry mouth)
Idiopathic sensory neuronopathy (GBS variant)
Other chemotherapeutic agents
Vitamin B6 toxicity
HIV-related sensory neuronopathy
6/7/2023 PNS 25
26. Patterns…..
Pattern 9: Autonomic Symptoms and Signs
– Consider neuropathies associated with prominent
autonomic dysfunction:
Hereditary sensory and autonomic neuropathy
Amyloidosis (familial and acquired)
Diabetes mellitus
Idiopathic pan-dysautonomia (may be a variant of
Guillain-Barré syndrome)
HIV-related autonomic neuropathy
Other chemotherapeutic agents
6/7/2023 PNS 26
27. Electro – diagnostic studies
– The electro-diagnostic (EDx) evaluation of patients
with a suspected peripheral neuropathy consists of
Nerve conduction studies (NCS)
Needle electromyography (EMG).
Studies of autonomic function can be valuable.
6/7/2023 PNS 27
28. Electro – diagnostic studies
– The electro-physiologic data provides additional information
about the distribution of the neuropathy that will support or
refute the findings from the history and physical examination;
• It can confirm whether the neuropathic disorder is a
mononeuropathy, multiple mononeuropathy
(mononeuropathy multiplex), radiculopathy, plexopathy, or
generalized polyneuropathy.
– Similarly, EDx evaluation can ascertain whether the process
involves only sensory fibers, motor fibers, autonomic fibers, or a
combination of these.
6/7/2023 PNS 28
29. Electro – diagnostic studies
Finally, the electro physiologic data can help distinguish
axonopathies from myelinopathies as well as axonal
degeneration secondary to ganglionopathies from the
more common length-dependent axonopathies
– Autonomic studies are used to assess small myelinated
(A-delta) or unmyelinated (C) nerve fiber involvement.
6/7/2023 PNS 29
30. Electro – diagnostic studies
Such autonomic testing includes
Heart rate response to deep breathing,
Heart rate, and blood pressure response to both the
Valsalva maneuver and tilt-table testing
Quantitative sudomotor axon reflex testing .
– These studies are particularly useful in patients who
have pure small-fiber neuropathy or autonomic
neuropathy in which routine NCS are normal.
6/7/2023 PNS 30
31. Other studies
Nerve Biopsy
– Nerve biopsies are now
rarely indicated for
evaluation of neuropathies
– Nerve biopsies should only
be done if the NCS studies
are abnormal.
– The sural nerve is most
commonly biopsied because
it is a pure sensory nerve and
biopsy will not result in loss
of motor function
Indications for nerve biopsy
Vasculitis
Amyloidosis, Sarcoidosis
Hansen's disease (leprosy)
Polyglucosan body disease
Tumor infiltration
Charcot-Maric-Tooth
disease types 1 and 3
Chronic inflammatory
demyelinating
polyradiculoneuropathy
Paraproteinemic PN
6/7/2023 PNS 31
32. Other studies
Skin Biopsy
– Skin biopsies are sometimes used to diagnose a small-fiber
neuropathy.
– Following a punch biopsy of the skin in the distal lower
extremity, immunologic staining can be used to measure the
density of small un-myelinated fibers.
– The density of these nerve fibers is reduced in patients with
small-fiber neuropathies in whom nerve conduction studies and
routine nerve biopsies are often normal.
6/7/2023 PNS 32
34. Etiologies – mono-neuropathy
– Mono-neuropathy means focal involvement of a single nerve
and implies a local process.
– Direct trauma, compression or entrapment, vascular lesions,
and neoplastic infiltration are the most common causes.
– Electrophysiological studies provide a more precise
localization of the lesion than may he possible by clinical
examination and can separate axonal loss from focal segmental
demyelination.
– Risk factors – DM, hypothyroidism, acromegally, HNPP
6/7/2023 PNS 34
35. Etiologies – mono-neuropathy multiplex
– Multiple mononeuropathy or mononeuropathy
multiplex signifies simultaneous or sequential damage
to multiple non contiguous nerves.
– Confluent multiple mono neuropathies may give rise to
motor weakness with sensory loss that can simulate a
peripheral poly-neuropathy.
– Ischemia caused by systemic, non-systemic, or mono-
systemic (peripheral nerve) vasculitis or micro-
angiopathy in diabetes mellitus should be considered
6/7/2023 PNS 35
36. Etiologies – mono-neuropathy multiplex
Axonal Injury
Vasculitis (systemic,
non-systemic)
Diabetes mellitus
Sarcoidosis
Hansen's disease
HIV
Demyelinating Injury
Multifocal acquired
demyelinating sensory and motor
neuropathy
Multifocal motor neuropathy
Multiple compression
neuropathies (hypothyroidism,
diabetes)
Hereditary neuropathy with
liability to pressure palsies
6/7/2023 PNS 36
37. Etiologies – poly-neuropathy
– Poly-neuropathy is characterized by symmetrical, distal motor,
and sensory deficits that have a graded increase in severity
distally and by distal attenuation of reflexes.
– The sensory deficits produce a stocking-glove pattern.
• By the time sensory disturbances have reached the level of
the knees, paresthesias are noted in the tips of the fingers
• When the sensory impairment reaches the mid thigh,
involvement of anterior inter-costal and lumbar segmental
nerves gives rise to a tent-shaped area of hypesthesia on the
anterior chest and abdomen.
6/7/2023 PNS 37
38. – Motor weakness is greater in extensor muscles than
in corresponding flexors.
– For example; walking on heels is affected earlier than
toe walking in most poly-neuropathies.
– It is helpful to determine the relative extent of
sensory, motor, and autonomic neuron involvement,
although most poly-neuropathies produce mixed
sensori-motor deficits and some degree of autonomic
dysfunction
6/7/2023 PNS 38
39. Etiologies - PN with Motor predominance
PN with Facial N involved
Guillain-Barre syndrome
Chronic inflammatory
polyradiculoneuropathy (rare)
Lyme disease
Sarcoidosis
Human immunodeficiency virus
1 infection
Gelsolin familial amyloid
neuropathy (Finnish)
Tangier disease
PN with predominate motor
Motor neuron disease
Multifocal motor neuropathy
Guillain-Barre syndrome
Acute motor axonal neuropathy
Porphyric neuropathy
Chronic inflammatory
polyradiculoneuropathy
Neuropathy with osteosclerotic
myeloma
Diabetic lumbar radiculoplexopathy
Hereditary motor sensory
neuropathies
Lead intoxication
6/7/2023 PNS 39
40. Etiologies- PN with autonomic involvement
Acute
• Acute pan-autonomic
neuropathy (idiopathic,
paraneoplastic)
• Guillain-Barre syndrome
• Porphyria
• Toxic neuropathy
Chronic
• Diabetes mellitus
• Amylaoid neuropathy (familial
and primary)
• Para-neoplastic sensory
neuronopathy
• HIV related autonomic
neuropathy
• Hereditary sensory and
autonomic neuropathy
6/7/2023 PNS 40
43. Etiologies - Radiculopathy
– Radicular pain and paresthesias are accompanied by sensory loss in the
dermatome (the area of skin innervated by one nerve root),
– Weakness in the myotome (defined as muscles innervated by the same
spinal cord segment and nerve root), and
– Diminished deep tendon reflex activity at a segmental level sub served
by the nerve root in question.
– When many roots are involved by a disease process it causes poly-
radiculopathy.
6/7/2023 PNS 43
44. Etiologies - Radiculopathy
– A disorder of the nerve roots is favored by abnormalities of the CSF
(raised protein concentration and pleocytosis),
– Of the para-spinal muscle needle electromyographic (EMG)
examination (presence of positive shatp waves and fibrillation
potentials), and
– Of spinal cord magnetic resonance imaging (MRI) (compromise or
contrast enhancement of the nerve roots per se).
6/7/2023 PNS 44
45. Etiologies - Plexopathy
– Brachial Plexopathy depends on extent and location of part of
the plexus involved.
– In a pan-plexopathy, paralysis of muscles supplied by
segments C5 through T1 occurs.
• The arm hangs lifelessly by the side, except that an intact trapezius
allows shrugging of the shoulder.
• The limb is flaccid and areflexic, with complete sensory loss below a
line extending from the shoulder diagonally downward and medially to
the middle of the upper arm.
6/7/2023 PNS 45
46. Etiologies - Plexopathy
– Lesions of the upper trunk produce weakness and sensory loss
in a C5 and C6 distribution.
• Affected muscles include the supraspinati and infraspinati,
biceps, brachialis, deltoid, and brachioradialis,
• So the patient is unable to abduct the arm at the shoulder or
flex at the elbow.
• The biceps and brachioradialis reflexes are diminished or
absent,
• Sensory loss is found over the lateral aspect of the arm,
forearm, and thumb.
6/7/2023 PNS 46
47. Etiologies -a Plexopathy
– Lesions of the lower trunk produce weakness, sensory loss,
and reflex changes in a C8 and T1 distribution.
• Weakness is present in both median- and ulnar-supplied
intrinsic hand muscles and in the medial finger and wrist
flexors.
• The finger flexion reflex is diminished or absent, and
• There is sensory loss over the medial two fingers, the
medial aspect of the hand, and the forearm
6/7/2023 PNS 47
48. Patho-physiology of peripheral nerves
• Despite the large number of causes of neuropathy, the peripheral
nerve has a limited repertoire of pathological reactions to physical
or metabolic insults.
• In general, these pathological reactions can be divided into four
main categories:
(1) Wallerian degeneration, which is the response to axonal
interruption;
(2) Axonal degeneration or axonopathy;
(3) Primary neuronal (perikaryal) degeneration or
neuronopathy
(4) Segmental demyelination.
6/7/2023 PNS 48
49. Pathology - Wallerian degeneration
– Any type of mechanical injury that causes interruption of axons leads
to wallerian degeneration
– Degeneration of axons and their myelin sheaths distal to the site of
transection.
– Regeneration from the proximal stump begins as early as 24 hours
following transection but proceeds slowly and is often incomplete.
– The quality of recovery depends on the degree of preservation of the
Schwann cell-basal lamina tube and the nerve sheath and
surrounding tissue, the distance of the site of injury from the cell
body, and the age of the individual
6/7/2023 PNS 49
50. Pathology – Axonal degeneration
– The most common pathological reaction of peripheral nerve,
signifies distal axonal breakdown resembling wallerian
degeneration, presumably caused by metabolic derangement
within neurons.
– Systemic metabolic disorders, toxin exposure, and some
inherited neuropathies are the usual causes of axonal
degeneration.
– The myelin sheath breaks down concomitantly with the axon in
a process that starts at the most distal part of the nerve fiber
and progresses toward the nerve cell body, hence the term
dying back neuropathy
6/7/2023 PNS 50
51. Pathology – Axonal degeneration
– Clinically, dying-back neuropathy presents with
symmetrical, distal loss of sensory and motor function
in the lower extremities and extends proximally in a
graded manner.
– The result is sensory loss in a stocking-like pattern,
distal muscle weakness and atrophy, and loss of ankle
reflexes.
– Because axonal regeneration proceeds at a maximal
rate of 2-3 mm per day, recovery may be delayed and
is often incomplete.
6/7/2023 PNS 51
53. Pathology - Neuronopathy
– Neuronopathy designates primary loss or destruction of nerve
cell bodies with resultant degeneration of their entire
peripheral and central axons.
– Either lower motor neurons or dorsal root ganglion cells may
be affected.
– A number of toxins such as organic mercury compounds,
doxorubicin, and high dose pyridoxine produce primary
sensory neuronal degeneration.
– Immune-mediated inflammatory damage of dorsal root
ganglion neurons occurs in para-neoplastic sensory
neuronopathy and other conditions.
6/7/2023 PNS 53
55. Pathology – Segmental demyelination
– The term segmental demyelination implies injury of either myelin
sheath or Schwann cells, resulting in breakdown of myelin sheaths
with sparing of axons.
– This occurs in immune-mediated demyelinating neuropathies and in
hereditary disorders of Schwann cell-myelin metabolism.
– Primary myelin damage may be produced toxic agents, such
diphtheria toxin, or
– Mechanically by acute nerve compression.
6/7/2023 PNS 55
56. Pathology – saegmental demyelination
Remyelination of demyelinated segments usually
occurs within weeks.
– The newly formed re-myelinated segments have
thinner-than-normal myelin sheaths and internodes
of shortened length.
– Repeated episodes of demyelination and
remyelination produce proliferation of multiple
layers of Schwann cells around the axon, termed an
onion bulb.
6/7/2023 PNS 56
57. Pathology – segmental demyelination
– Relative sparing of temperature and pinprick sensation in many
demyelinating neuropathies reflects preserved function of un-
myelinated and small diameter myelinated fibers.
– Early generalized loss of reflexes, disproportionately mild muscle
atrophy in the involved proximal and distal weakness,
– Neuropathic tremor, and
– Palpably enlarged nerves are all clinical clues that suggest
demyelinating neuropathy.
6/7/2023 PNS 57
60. Entrapment neuropathies
Entrapment neuropathy is defined as a focal
neuropathy caused by restriction or mechanical
distortion of a nerve within a fibrous or fibro-
osseous tunnel or less commonly by other structures
such as bone, ligament, other connective tissues,
blood vessels, or mass lesions.
– Compression, constriction, angulation, or stretching
are important mechanisms that produce nerve injury
at certain vulnerable anatomical sites
6/7/2023 PNS 60
63. Entrapment neuropathies
Median neuropathy ( Carpel Tunnel Syndrome)
– CTS is a compression of the median nerve in the
carpal tunnel at the wrist.
– The median nerve enters the hand through the carpal
tunnel by coursing under the transverse carpal
ligament.
– The symptoms of CTS consist of numbness and
paresthesias variably in the thumb, index, middle, and
half of the ring finger.
6/7/2023 PNS 63
64. Entrapment neuropathies
– At times, the paresthesias can include the entire hand and extend
into the forearm or upper arm or can be isolated to one or two
fingers.
– Pain is another common symptom and can be located in the hand
and forearm and, at times, in the proximal arm.
– The signs of CTS are decreased sensation in the median nerve
distribution; reproduction of the sensation of tingling when a
percussion hammer is tapped over the wrist (Tinel's sign) or the
wrist is flexed for 30–60 s (Phalen's sign); and weakness of thumb
opposition and abduction.
6/7/2023 PNS 64
65. Entrapment neuropathies
– EDx is extremely sensitive and shows slowing of sensory and, to
a lesser extent, motor median potentials across the wrist.
– Treatment options consist of
Avoidance of precipitating activities;
Control of underlying systemic-associated conditions if present;
Non steroidal anti-inflammatory medications;
Neutral (volar) position wrist splints, especially for night use;
Glucocorticoid/anesthetic injection into the carpal tunnel; and
Surgical decompression by dividing the transverse carpal ligament.
6/7/2023 PNS 65
66. Radiculopathy
– Radiculopathies
are most often due
to compression
from degenerative
joint disease and
herniated disks,
but there are a
number of
unusual
etiologies.
6/7/2023 PNS 66
67. Plexopathy
Brachial Plexopathy
– The brachial plexus is composed of three
trunks (upper, middle, and lower), with
two divisions (anterior and posterior) per
trunk.
– Subsequently, the trunks divide into three
cords (medial, lateral, and posterior),
– And from these arise the multiple terminal
nerves innervating the arm.
– The anterior primary rami of C5 and C6
fuse to form the upper trunk;
– The anterior primary ramus of C7
continues as the middle trunk,
– While the anterior rami of C8 and T1 join
to form the lower trunk.
6/7/2023 PNS 67
68. Plexopathy - Etiologies
Immune mediated BP
– Immune-mediated brachial plexus neuropathy (IBPN) goes by
various terms, including acute brachial plexitis, neuralgic
amyotrophy, and Parsonage-Turner syndrome.
– IBPN usually presents with an acute onset of severe pain in the
shoulder region.
– The intense pain usually lasts several days to a few weeks, but a dull
ache can persist.
– Individuals who are affected may not appreciate weakness of the arm
early in the course because the pain limits movement.
– However, as the pain dissipates, weakness and often sensory loss are
appreciated.
– Attacks can occasionally recur
6/7/2023 PNS 68
69. Plexopathy - Etiologies
– The most common pattern of IBPN involves the upper trunk or a single or
multiple mono-neuropathies primarily involving the supra-scapular, long
thoracic, or axillary nerves.
– Additionally, the phrenic and anterior inter-osseous nerves may be
concomitantly affected.
– Any of these nerves may also be affected in isolation.
– EDx is useful to confirm and localize the site(s) of involvement.
– Empirical treatment of severe pain with glucocorticoids is often used in the
acute period.
6/7/2023 PNS 69
70. Plexopathy - Etiologies
Other causes of Brachial
Plexopathy
Traumatic and post Surgery
Neoplastic
Radiation
6/7/2023 PNS 70
71. Plexopathy
Lumbo-sacral Plexus
– The lumbar plexus arises from the ventral
primary rami of the first to the fourth lumbar
spinal nerves.
– These nerves pass downward and laterally from
the vertebral column within the psoas major
muscle.
– The femoral nerve derives from the dorsal
branches of the second to the fourth lumbar
ventral rami.
– The obturator nerve arises from the ventral
branches of the same lumbar rami.
– The lumbar plexus communicates with the sacral
plexus by the lumbosacral trunk, which contains
some fibers from the fourth and all of those from
the fifth lumbar ventral rami
6/7/2023 PNS 71
73. Chronic inflammatory demyelinating PN (CIDP)
CIDP is distinguished from GBS by its chronic course.
– This neuropathy shares many features with the
common demyelinating form of GBS, including
elevated CSF protein levels and the Edx findings of
acquired demyelination.
– Most cases occur in adults, and males are affected
slightly more often than females.
– The incidence of CIDP is lower than that of GBS, but
due to the protracted course the prevalence is greater.
6/7/2023 PNS 73
74. CIDP
Clinical features
– Onset is usually a gradual over a few months or longer, but in
a few cases the initial attack is indistinguishable from that of
GBS.
– An acute-onset form of CIDP should be considered when GBS
deteriorates >9 weeks after onset or relapses at least three
times.
– Symptoms are both motor and sensory in most cases.
– Weakness of the limbs is usually symmetric but can be
strikingly asymmetric.
– Multifocal acquired de-myelinating sensory and motor
(MADSAM) neuropathy variant (Lewis-Sumner syndrome) in
which discrete peripheral nerves are involved
6/7/2023 PNS 74
75. CIDP
– There is considerable variability from case to case.
– Some patients experience a chronic progressive
course, whereas others, usually younger patients, have
a relapsing and remitting course.
– Some have only motor findings, and a small
proportion present with a relatively pure syndrome of
sensory ataxia.
6/7/2023 PNS 75
76. CIDP
– Tremor occurs in 10% and may become more
prominent during periods of subacute worsening or
improvement.
– A small proportion have cranial nerve findings,
including external ophthalmoplegia.
– CIDP tends to ameliorate over time with treatment;
– The result is that many years after onset, nearly 75%
of patients have reasonable functional status.
6/7/2023 PNS 76
77. CIDP
Diagnosis
–The diagnosis rests on characteristic
clinical, CSF, and electro-physiologic
findings.
–The CSF is usually acellular with an
elevated protein level, sometimes several
times normal.
6/7/2023 PNS 77
78. CIDP
– As with GBS, a CSF pleocytosis should lead to the
consideration of HIV infection, leukemia or lymphoma, and
neurosarcoidosis.
– Edx findings reveal variable degrees of conduction slowing,
prolonged distal latencies, distal and temporal dispersion of
CMAPs, and conduction block as the principal features.
– In particular, the presence of conduction block is a certain
sign of an acquired demyelinating process.
6/7/2023 PNS 78
79. CIDP
In all patients with presumptive CIDP, it is also reasonable to
exclude
Vasculitis, Collagen vascular disease
Chronic hepatitis, HIV infection,
Amyloidosis Diabetes mellitus.
IBD Lymphoma.
6/7/2023 PNS 79
80. CIDP
Pathogenesis
– Although there is evidence of immune activation in CIDP, the
precise mechanisms of pathogenesis are unknown.
– Biopsy typically reveals little inflammation and onion-bulb
changes (imbricated layers of attenuated Schwann cell
processes surrounding an axon) that result from recurrent
demyelination and remyelination.
– The response to therapy suggests that CIDP is immune-
mediated; CIDP responds to glucocorticoids, whereas GBS
does not.
– Approximately 25% of patients with clinical features of CIDP
also have a monoclonal gammopathy of undetermined
significance (MGUS).
6/7/2023 PNS 80
81. CIDP
Treatment
– Most authorities initiate treatment for CIDP when
progression is rapid or walking is compromised.
– If the disorder is mild, management can be
expectant, awaiting spontaneous remission.
– Controlled studies have shown that high-dose IVIg,
PE, and glucocorticoids are all more effective than
placebo.
6/7/2023 PNS 81
82. CIDP
Initial therapy is usually with IVIg, administered as
2.0 g/kg body weight given in divided doses over 2–
5 days; three monthly courses are generally
recommended before concluding a patient is a
treatment failure.
– If the patient responds, the infusion intervals can be
gradually increased or the dosage decreased (e.g., 1
g/kg per month).
6/7/2023 PNS 82
83. CIDP
– PE, which appears to be as effective as IVIg, is
initiated at two to three treatments per week for 6
weeks; periodic re-treatment may also be required.
– Treatment with glucocorticoids is another option (60–
80 mg prednisone PO daily for 1–2 months, followed
by a gradual dose reduction of 10 mg per month as
tolerated),
– Patients who fail therapy with IVIg, PE, and
glucocorticoids may benefit from treatment with
immunosuppressive agents such as azathioprine,
methotrexate, cyclosporine, and cyclophosphamide,
either alone or as adjunctive therapy.
6/7/2023 PNS 83
