Transcript Diseases of Peripheral Nerves

DISEASES OF
PERIPHERAL NERVES
DR
BASHAR SHAKER
Numerous inherited and acquired
pathological processes may affect the nerve
roots (radiculopathy), the nerve plexuses
(plexopathy) and/or the individual nerves
(neuropathy).
Cranial nerves 3-12 share the same tissue
characteristics as peripheral nerves
elsewhere and are subject to the same
range of diseases. Nerve fibres of different
types (motor, sensory or autonomic) and of
different sizes may be variably involved.
Disorders may be primarily directed at the
axon, the myelin sheath (Schwann cells) or
the vasa nervorum
PATTERN OF INVOLVMENT
Mononeuropathy Simplex=Single Nerve
Mononeuropathy Multiplex=Several Nerves
Randomly &Noncontiguously
Polyneuropathy( Peripheral
Neuropathy)=Dysfunction of Numerous
Peripheral Nerves at the Same Time leading
to predominantly distal & symmetrical deficit
usually affecting lower more than upper
limbs
Types &Causes of peripheral neuropathy
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Diseases of Peripheral Nerves
SYMPTOMS &SIGNS
1.Sensory Disturbances
A.Numbness, Hyperpathia, Impaired Sensation &
SPONTANEOUS PAIN esp. in SMALL FIBER
involvement ;D. M. , Porphyria, AIDS, Alcoholic,
Entrapment …..
B. Dissociated Sensory Loss
Small Fib. Pain &Temp.
Large Fib. Touch, Vib. & Position
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2. MOTOR DEFICITS
Weakness , Wasting , Fasciculation
Diminished or Absent Reflexes
i.e. LMNL
3.AUTONOMIC DISTURBANCES
Post. Hypotension, Coldness, Imp. Sweating,
Impotence….esp. GBS, Diabetes, Renal Failure,
Porphyria….
4. ENLARGED NERVES
Leprosy, Amyloidosis, HSMN, Refsum Dis.,
Acromegaly..
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Causes of P. N .
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1. Inflammatory: GBS , CIPD
2. Metabolic &Nutritional :D.M. ,Uremia, Liver Failure,
Hypothyroidism, Acromegaly, B12 Deficiency….
3.Infectious &Granulomateous:AIDS, Leprosy,
Diphtheria, Sarcoidosis…
4.Vasculitis: PAN, SLE, Rh.Arthritis…
5.Neoplastic &Paraneoplastic
6. Drugs &Toxins:Alcohol, INH, Vinicristine, Phenytoin, Heavy
Metals….
7.Hereditory:HSMN, HSN, Refsum Disease,Porphyria..
8. IDIOPATHIC
Drugs causing peripheral
neuropathy
‫لالطالع‬
Cardiovascular
agents
Amiodarone , statins , hydralazine
Chemotheraputic
agents
Cisplatine , thalidomide ,
vincristine
Anti-infective
agents
Chloramphenicol , INH , ETB ,
nitrofurantoin , metronidazole
Others
Gold , disulfiram , pyridoxine ,
tacrolimus , colchicine , phenytoin
EVALUATION OF PATIENTS
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TIME COURSE=Acute; Inflamm., Infectious, Toxins…
Chronic;Hereditory, Metabolic…
AGE= Early; Hereditory
Late; Metabolic, Neoplastic
OCCUPATION= Exposure to toxins
MEDICAL HISTORY
DRUGS
FAMILY HISTORY
DIFFERENTIAL DIAGNOSIS
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Diseases of muscles &n.m. junction
normal sensation& tendon reflexes
Diseases of spinal cord
pyramidal signs &sensory level below the
lesion
Radiculopathies
dermatomal &myotomal distribution
INVESTIGATIONS
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CONFIRM DIAGNOSIS
EMG = DENERVATION
ENG &NCV = Demyelination or Axonal
Degeneration
REVEAL UNDERLYING CAUSE
INVESTIGATION OF PERIPHERAL NEUROPATHY
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INVESTIGATION OF PERIPHERAL NEUROPATHY
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TREATMENT
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UNDERLYING CAUSE
NURSING CARE ? ULCERS &CONTRACTURES
RESPIRATORY MONITORING &MANAGEMENT
CARE OF SKIN &NAILS
RELIEF OF PAIN ----Lancinating Pain--PHENYTOIN
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CARBAMAZEPINE
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MEXILETINE
Constant Pain----AMITRIPTYLINE
GABAPENTINE
GUILLIAN BARIE SYNDROME
ACUTE ASCENDING POLYRADICLONEUROPATHY
This syndrome of acute paralysis develop in 70 %
of patients 1-4 weeks after respiratory infection or
diarrhoea (particularly Campylobacter).
In Europe and North America, acute inflammatory
neuropathy is most commonly demyelinating (
AIDP ).
Axonal variants ,either ( AMAN ) or (ASMAN) are
more common in China and Japan .
Clinical features
Distal paraesthesia and limb pains precede a
rapidly ascending muscle weakness from lower to
upper limbs , more marked proximally than
distally.
Facial and bulbar weakness commonly develops ,
and respiratory weakness requiring ventilatory
support occurs in 20 % of cases .
In most patients weakness progresses for 1-3
weeks but rapid deterioration to respiratory failure
can develop within hours
On examination there is diffuse weakness with
widespread loss of reflexes.
An unusual axonal variant described by Miller
Fisher comprises the triad of ophthalmoplegia ,
ataxia and areflexia .
Overall, 80% of patients recover completely within
3-6 months, 4% die, and the remainder suffer
residual neurological disability which can be
severe. Adverse prognostic features include older
age, rapid deterioration to ventilation and evidence
of axonal loss on EMG.
Investigations
The CSF protein is abnormal at some stage
of the illness, but may be normal in the first
10 days. There is usually no rise in CSF cells
( lymphocytosis of > 50/ml suggests an
alternative diagnosis ).
Electrophysiological studies are often normal
in the early stages but show typical changes
after a week or so , with conduction block
and multifocal motor slowing , sometimes
most evident proximally as delayed F-waves.
Management
During the phase of deterioration , regular
monitoring of respiratory function ( vital
capacity and arterial blood gases) is
required, as respiratory failure may develop
with little warning and require ventilatory
support.
Ventilation may be needed if the vital
capacity falls below 1L , but ventilation is
more often required because of bulbar
weakness leading to aspiration.
General management to protect the airway
and prevent pressure sores and venous
thrombosis is essential .
Corticosteroids have been shown to be
ineffective .
Plasma exchange and intravenous
immunoglobulin therapy shorten the
duration of the illness ,reduce severity and
improve prognosis provided treatment is
started within 14 days of the onset of
symptoms .
Chronic demyelinating polyneuropathy
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It is either hereditary or immune-mediated.
Charcot-Marie-Tooth (CMT) disease which is
of many types ;the most commom 70-80 %
is the autosomal dominant one causing
distal wasting (inverted champagne bottle or
stork leg ) often with pes cavus and a
predominantely motor involvement
Chronic demyelinating polyneuropathy
Presents with a relapsing or progressive
generalized neuropathy.
Sensory,motor or autonomic nerves can be
involved but the signs are predominantely
motor .
Multifocal Motor Neuropathy MMN is a
variant with motor involvement only .
CIDP
‫لالطالع‬
CIDP usually responds to immunosuppressive
treatment ;corticosteroids , methotrexate or
cyclophosphamide OR to immunomodulatory
treatments (plasma exchange or IVIg ),which is
the best of patients with MMN .
About 10 % of patients with acquired
demyelinating polyneuropathy have an abnormal
serum paraprotein , sometimes associated with a
lymphoproliferative malignancy .
DIABETIC NEUROPATHY
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AMYOTROPHY = PAIN &WEAKNESS WITH ATROPHY
PELVIC GIRDLE &THIGH MUSCLES WITH ABSENT KNEE
REFLEX &LITTLE SENSORY LOSS
MONONEUROPATHY = ACUTE PAINFUL CRANIAL
NERVES
BOTH HAVE GOOD PROGNOSIS
Entrapment neuropathy
Focal compression or entrapment is the
usual cause of mononeuropathy . However
, some patients present with what initially
appears to be a single nerve lesion and
then go on to develop multiple nerve
lesions.This is termed mononeuritis
multiplex .
Symptoms and signs
Nerve
Median
at wrist) (
(carpal tunnel
)syndrome
Ulnar
)at elbow(
Symptoms
Muscle
weakness/muscle
-wasting
Pain and
Abductor pollicis
brevis
paraesthesia on
palmar aspect of
hands and
fingers, waking
the patient from
sleep. Pain may
extend to arm
and shoulder
Area of sensory
loss
Lateral palm
and thumb,
index, middle
and medial half
4th finger
Paraesthesia on
All small hand Medial palm and
medial border of
muscles,
little finger, and
hand, wasting
excluding
medial half 4th
finger
and weakness abductor pollicis
of hand muscles
brevis
Nerve
Symptoms
Radial
Weakness of
extension of wrist
and fingers, often
precipitated by
sleeping in
abnormal posture,
e.g. arm over
back of chair
Wrist and finger
extensors,
supinator
Dorsum of thumb
Peroneal
Foot drop, trauma
to head of fibula
Dorsiflexion and
eversion of foot
Nil or dorsum of
foot
Lateral
cutaneous
nerve of the
meralgia ( thigh
)paraesthetica
Tingling and
dysaesthesia on
lateral border of
the thigh
Nil
Lateral border of
thigh
Muscle
Area of sensory
loss
weakness/musc
le-wasting
In an entrapment neuropathy, pressure
initially damages the myelin sheath, and
neurophysiology will show slowing of
conduction over the relevant site.
Sustained or severe pressure damages the
integrity of the axons, demonstrable as
loss of the sensory action potential distal
to the site of compression.
Certain conditions increase the propensity to
develop entrapment neuropathies. These include
acromegaly, hypothyroidism, pregnancy, any
pre-existing mild generalised axonal neuropathy
(e.g. diabetes), and oseophytes. Patients with
multiple recurrent entrapment neuropathies,
especially at unusual sites, should be screened
for autosomal dominant hereditary neuropathy
with liability to pressure palsies (HNPP) .
Unless axonal loss has occurred, entrapment
neuropathies will recover, provided the
pressure on the nerve is relieved, either
by avoiding precipitating activities or limb
positions, or by surgical decompression.
Entrapment neuropathy
CTS
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MEDIAN N. COMPRESSION AT THE WRIST
IDIOPATHIC, PREGNANCY, TRAUMA, ARTHRITIS, MYXOEDEMA,
ACROMEGALY, TENOSYNOVITIS……
PAIN, NUMBNESS IN MEDIAN N. DISTIBUTION ?SHOULDER
> AT NIGHT
WEAKNESS & ATROPHY OF THENAR MUSCLES
TINEL SIGN , PHALEN MANEUVER
Rx LOCAL STEROIDS, WRIST SPLINT, SURGERY
Facial nerve palsy
Idiopathic facial nerve palsy or Bells palsy is a
common condition affecting all ages and both
sexes .The lesion is within the facial canal and
may be due to reactivation of latent herpes
simplex virus 1 infection .Symptoms usually
develop subacutely over a few hours , with pain
around the ear preceding the unilateral facial
weakness. Patients often describe the face as
numb but there is no objective sensory loss
(except possibly to taste).
Hyperacusis can occur if the nerve to
stapedius is involved , and there may be
diminished salivation and tear secretion .
Examination reveals an ipsilateral lower
motor neuron facial nerve palsy . Vesicles
in the ear or on the palate indicate that
the facial palsyis due to herpes zoster
rather than Bells palsy .
Prednisolone 40-60 mg daily for a week speeds recovery if
started within 72 hours.Artificial tears and ointment
prevent exposure keratitis and the eye should be taped
shut overnight. About 80% of patients recover
spontaneously within 12 weeks. A slow or poor recovery
is predicted by complete paralysis, older age and
reduced facial motor action potential amplitude after the
first week. Recurrences can occur but should prompt
further investigation. Aberrant re-innervation may occur
during recovery, producing unwanted facial movements
(e.g. eye closure when the mouth is moved) or 'crocodile
tears' (tearing during salivation).
MOTOR NEURONE DISEASE
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DEGENERATION OF MOTOR NEURONS IN SPINAL
CORD MOTOR NUCLIE OF LOWER CRANIAL
NERVES ,
ONSET 30 -60 YEARS, > IN MALES, 2/ 100000,
SPORADIC, 5- 10 %FAMILIAL ( AUT. DOM. ) CHR 15
CAUSE : UNKNOWN
?AUTOIMMUNE
INCREASED OFR FORMATION
REDUCED NEUROTROPHIC FACTORS
EXCITOTOXINS
CLINICAL TYPES &FEATURES
A. PROGRESSIVE BULBAR PALSY = LMN CRANIAL NERVES
B.PSEUDOBULBAR PALSY = UMN CRANIAL NERVES
C.SPINAL MUSCULAR ATROPHY = LMN SPINAL CORD AHC
D. PURE LATERAL SCLEROSIS = UMN IN LIMBS
E. AMYOTROPHIC LAT. SCLEROSIS = MIXED C. & D.
MAY BE WITH A. & B.
NO EXTRA OCULAR MUSCLES INVOLVEMENT
NO SPHINCTER INVOLVEMENT
NO SENSORY DEFICIT
NORMAL CSF
EMG
Rx = RILUZOLE 100mg /day may slow progression & reduce
mortality. It is GLUTAMATE ANTAGONIST . Side effects =
fatigue, dizziness, GIT diturbance, raised liver enzymes.
Anticholinergics for drolling of saliva
Physiotherapy
FEEDING = Semisolid diet, NG tube, Gastrostomy.
Tracheostomy
Prognosis = Bad especially in Bulbar type
Progressive &fatal in 3 -5 years
MND IN CHILDREN
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INFANTILE = WERDING HOFFMANN DIS ONSET AT 3 MONTHS ,
DEATH
AT 3 YEARS, AR , DIFFICULT SUCKING , SWALLOWING&
VENTILATION, ATROPHY & FASCICULATION OF TONGUE &
LHMB MUSCLES, NO SENSORY DEFICIT , NO Rx
INTERMEDIATE = CHRONIC W-H-DISEASE
AR, 2nd of 1st year, LESS BULBAR INVOLVEMENT ,
> BENIGN, SLOWLY PROGRESSIVE , KYPHOSCOLIOSIS
&CONTRACTURES , SURVIVE TO ADULTHOOD
JUVENILE
= KUGELBERG – WELANDER DISEASE
AR, COULD BE AD OR X – LINKED
ONSET AT CHILDHOOD OR EARLY ADOLESCENCE
MORE IN PROXIMAL MUSCLES , LITTLE BULBAR INVOLV.
DISABILITY IN EARLY ADULT LIFE
NO Rx
SYRINGOMYELIA
‫لالطالع‬
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CAVITATION OF SPINAL CORD
COMMUNICATING = CENTRAL CANAL &THE CAVITY
NON – COMMUN. = CYSTIC DILATATION OF SPINAL CORD
CLINICALLY = DISSOCIATED SENSORY LOSS
WEAK. & WASTING OF MUSCLES ; CERVICAL &T 1
PYRAMIDAL SIGNS &SPHINCTER DIST. BELOW
NECK & RADICULAR PAIN
HORNER SYNDROME
SYRINGOBULBIA
MAY BE ASSO. WITH TUMOR, TRAUMA , ARACHNOIDITIS OR
ANMALIES LIKE ARNOLD – CHIARI MALFORMATION
Rx = DECOMPRESSION OF DISTENDED SYRINX
SUBACUTE COMBINED DEGEN. OF THE CORD
‫لالطالع‬
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B12 DEFICIENCY
PARASTHESIA &WEAKNESS OF THE EXTREMITIES = PERIPHERAL
NERVES
SPASTIC PARAPARESIS = PYRAMIDAL FIBERS
SENSORY ATAXIA = POSTERIOR COLUMN TRACT
LHERMITTS SIGN
SCOTOMAS = OPTIC ATROPHY
BEHAVIOURAL OR PSYCHIATRIC SYMPTOMS
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ANEMIA MEGALOPLASTIC
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PRESENT
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Rx B12I. M. …….
NOT NECESSARILY