Peripheral neuropathy and
muscular dystrophy
Awokech Berihun (MD)
December /2017
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objective
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After this lecture students will be able to:
Define PN
Know common causes of PN
Know Clinical presentation of common PN
Differentiate peripheral neuropathy and
muscular dystrophy
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• Peripheral nerves are nerves that send
messages to and receive from CNS to other
parts of the body
Skin, muscles, internal organs
• Peripheral neuropathy is a disorder of the
peripheral nerves of any cause
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Classification of PN
• Focal compressive
neuropathy
• Generalized
neuropathy
>100 types identified
30 – 40 % are
idiopathic
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Classification of PN
• According to types of nerves involved:
I. Sensory
II. Motor
III. autonomic
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Classification of PN….
o Motor: weakness, cramps,
fasciculation, atrophy
o Sensory:
large, heavily myelinated nerves
vibration, position and light touch will be
affected
Small sensory fibers
pain and temperature will be affected
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neuropathy…
o Autonomic nerves:
depends on organ involved
 sweating
 Heat intolerance
 BP instability
 Incontinence
 Bowel habit change
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Classification…
According to distribution of nerves affected
• Mononeuropathy
• Mononeuropathy multiplex
• Poly neuropathy
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Classification…
Mononeuropathy multiplex
 Multifocal neuropathy
• Random pattern of nerve involvement
• Asymmetric
• May/may not be pain full
• Isolated reflex loss
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Polyneuropathy
Distal symmetric polyneuropathy
Starts in feet, distal stocking pattern
Fairly symmetric
Decreased reflexes
Sensory > motor
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symptoms
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Numbness
Tingling
Burning
Crawling
Weakness
Mood change and fear
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Mechanism of injury
Demyelination ----- myelin sheath disrupted
GBS, post diphtheria
Axonal degeneration -------- axon damage
toxic neuropathy
Compression -----------focal demyelination
entrapment- carpel tunnel syndrome
Infarction --------- arteritis ( PAN)
Infiltration --------leprosy, sarcoidosis
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Distinguishing features
axonal
demylinating
neuronal
Distal areflexia
areflexia
areflexia
Amplitude affected >
velocity
Velocity affected >
Amplitude
Sensory amplitude affected
Axonal degeneration &
regeneration
Demyelination &
remyelination
Axonal degeneration ,
no regeneration
Slow recovery
Rapid recovery
Poor recovery
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causes
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Genetic
Autoimmune
Infections- HIV,
Toxins- diphteria, tetanus, boutulism
Medications- INH, metrinidazole, chemotherapuetic
agents
Vitamin deficiencies- VitB6,VitB12
Trauma
Endocrine- hypo/hyperthyroidism, DM, uremia
Medical conditions: renal, hepatic, Para neoplastic
idiopathic
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Patient evaluation
Hx:
Onset: acute/chronic
Part of body involved
Sequence of involvement
Symptoms: --------sensory
--------motor
--------autonomic
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• Associated findings
Pain full/painless?
Hereditary/sporadic?
• electromyography
Axonal / demyelinating
• Histology: Inflammatory cells
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P/E
Nerve thickening:
 leprosy
 diabetes
 amylodosis
neurofibromitosis
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• Neuropathy with cranial nerve damage
GBS
Lyme disease
Sarcoidosis
Look for: -muscle wasting
-Strength
-reflexes
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• If reflexes are decreased or lost
sign of PNP except in spinal shock
Ataxia: DM, miller fisher variant, sensory PNP
Sensory: temp
pain
vibration
position
proprioception
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Guillain-Barré Syndrome
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• Definition:
- Postinfectious polyneuropathy involving
mainly motor but sometimes also sensory
and autonomic nerves.
1. Acute Inflammatory Demyelinating
Polyneuropathy (AIDP)
2. Chronic Inflammatory Demyelinating
Polyneuropathy (CIDP)
• Most patients have a demyelinating neuropathy
• Primarily axonal degeneration occurs in some cases.
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Clinical Manifestations
• Affects people of all ages
• Paralysis usually follows a non-specific infection by
about 10 days
• Respiratory tract : Mycoplasma pneumoniae
• GI tract : Campylobacter jejuni ,H.pylori
• Weakness begins usually in the lower extremity &
progress to involve the trunk ,upper limbs and
finally bulbar muscles…Landry ascending paralysis
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• Onset is gradual & progresses over days or week
• Results in paresthesias and ascending ,symmetrical
Peripheral neuropathy
• Bulbar involvement
- Dysphagia ,facial weakness
- Respiratory insufficiency
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• Miller-Fisher syndrome
- Acute external ophthalmoplegia
facial weakness, ataxia , areflexia
• Tendon reflexes are lost ,usually early in the course
• Urinary retention or incontinence in 20 % of
patients
• Autonomic nervous system involvement
- Labile BP & HR , postural hypotension
,profound bradycardia
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• Chronic varieties of GBS
a) Chronic relapsing polyradiculoneuropathy
(chronic inflammatory demyelinating
polyradiculoneuropathy)
b) Chronic unremitting polyradiculoneuropathy
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Congenital GBS
• Generalized hypotonia ,weakness ,and areflexia in
affected neonate
• Gradual recovery in few months
• No residual disease by 1 yr of age
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Laboratory findings and Diagnosis
1) CSF: Protein > 2x upper limit of normal
No pleocytosis (< 10 WBC/mm3 )
- Dissociation b/n high CSF protein & a
lack of cellular response
2) Nerve conduction velocities:
- motor : greatly reduced
- sensory : Often slow
3) Electromyography : acute denervation of muscle
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4) Serum creatine kinase (CK) level: mildly elevated or
normal
5) Antiganglioside antibodies (mainly against GM1 &
GD1) :sometimes elevated
6) Muscle biopsy: normal or denervation atrophy
7) Sural nerve biopsy : segmental demyelination ,focal
inflammation ,wallerian degeneration
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Treatment
1 ) Rx of acute GBS
• Admit to the hospital for observation
(in early phase)
• IVIG for 2-5 days
• Plasmapheresis and/or immunosuppressive drugs
• Steroids : not effective
• IVIG + interferon
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• Supportive care
- respiratory support
- prevention of decubiti(bed sore) in child with
flaccid
tetraplegia
- Rx of secondary bacterial infections
2 ) Rx of chronic GBS
- IVIG
- Plasmapheresis (plasma exchange)
-Steroid :High dose pulsed methylprednisolone
- Immunosuppressive drugs
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• Bulbar and respiratory muscle involvement
may lead to death if not treated on time.
• Predictors of poor outcome :
1) Cranial nerve involvement
2) Intubation
3) Maximum disability at the time of presentation
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Muscular dystrophy
“muscular dystrophy”
refers to a group of genetically determined
disorders characterized by progressive
degeneration of skeletal muscle with out
primary structural abnormality in the lower
motor neuron
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Muscular dystrophy…
• Distinguished from all other neuromuscular
diseases by 4 obligatory criteria:
1. It is a primary myopathy
2. it has a genetic basis
3. the course is progressive
4. degeneration and death of muscle fibers
occur at some stage in the disease
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Muscular
Dystrophies
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Duchenne and Becker Muscular Dystrophies
myotonic dystrophy
congenital muscular dystrophy
Limb girdle muscular dystrophy
Facioscapulohumeral dystrophy
Emery-Dreifuss (scapulohumeral )muscular
dystrophy
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Duchenne and Becker Muscular
Dystrophies
• most common hereditary neuromuscular
disease
• affecting all races and ethnic groups
• incidence is 1 in 3,600 live born infant boys.
• inherited as an X-linked recessive trait
• abnormal gene is at the Xp21 locus
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CLINICAL MANIFESTATIONS
• affected boys are asymptomatic during early
infancy and have normal motor milestone
although some are mildly hypotonic
• Gowers sign is often evident by age 3 yr and is
fully expressed by age 5 or 6 y
• pseudo hypertrophy of the calf muscles
• Weakness of hip extensors – compensatory
lordosis
• ability to walk is lost generally before 13 year
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• Contractures most often involve the ankles,
knees, hips, and elbows.
• Scoliosis
• Cardiomyopathy, including persistent
tachycardia and myocardial failure, is seen in
50-80%
• Intellectual impairment occurs in all patients,
although only 20-30% have an IQ <70
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• Death occurs usually at about 18-20 yr of age.
The causes of death are :
• respiratory failure during sleep
• intractable heart failure
• pneumonia
• occasionally, aspiration and airway obstruction
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LABORATORY FINDINGS
serum CK level is consistently greatly elevated
15,000-35,000 IU/L (normal <160 IU/L
echo, ECG, and chest x-ray
Electromyography (EMG) shows characteristic
myopathic features
 No evidence of denervation is found.
 Motor and sensory nerve conduction
velocities are normal
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TREATMENT
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no medical cure
Supportive
Nutritional
Physiotherapy
Glucocorticoids decrease the rate of apoptosis
or programmed cell death
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Myotonic Muscular Dystrophy
• second most common muscular dystrophy
• AD inheritance, abnormal expansion of the
CTG or CCTG repeat
• Dysfunction in multiple organ systems
• Weakness is mild in the 1st few yr.
• Progressive wasting of distal muscles becomes
increasingly evident
• poorly Articulated speech
• heart block and arrhythmias
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Facial weakness, inverted V–shaped upper lip,
and loss of muscle mass in the temporal fossae
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treatment
• no specific medical treatment,
• Complications can be treated
 cardiac
endocrine
gastrointestinal
 ocular
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Congenital Muscular Dystrophies
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Severe involvement at birth
But often follow a more benign clinical course
high association with brain malformations
complicated by severe epilepsy
Autosomal recessive inheritance
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• joint contractures of variable severity
• respiratory and swallowing difficulties
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Limb-Girdle Muscular Dystrophies
• rapidly progressive
• autosomal recessive dystrophy
• mainly affect muscles of the hip and shoulder
girdles
• Distal muscles also eventually become
atrophic and weak
• loss of ambulation b/n 20 and 30 years
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FACIOSCAPULOHUMERAL
MUSCULAR DYSTROPHY
• Sn & sx begin in late childhood or early
adolescence
• facial & scapulohumeral muscles weakness
• deltoid strength is preserved
• pelvic girdle Weakness may result in a lordosis
• no cardiac or intellectual involvement
• Some retinal vasculopathy & sensorineural
hearing loss.
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•
A: facial weakness
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B:upward riding of
s scapulae(abduction)
sca
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ix
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Serum CK
Muscle biopsy
Echocardiography
EMG?
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Rx
• no definitive cure
 Supportive & medical/drug therapy
• Daily passive stretching of joint contractures (eg,
tendoachilles,
• ileotibial bands, hamstrings in DMD
• Night splints
• Bracing upon loss of ambulation
• Orthopedic surgery: surgical tendon releases,
scoliosis surgery
• Ventilatory support: noninvasive, tracheostomy
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THANK YOU!!
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