Upload
trinhdien
View
219
Download
0
Embed Size (px)
Citation preview
The peripheral nerves include:
• Cranial Nerves (not the 2nd CN)
• Spinal Nerve Roots
• Dorsal Root Ganglia
• Peripheral Nerve Trunks and their Terminal Branches
• Peripheral Autonomic Nervous System
• Neuropathic processes that present in childhood
– Progressive
• Hereditary/genetic
• Some immune mediated neuropathies
– Tend improve over time
• Acquired neuropathies
• Vitamin deficiencies
• Toxicities
• Immune mediated
• Focal mononeuropathies
Guillain-Barré syndrome
• Discuss the pathogenesis and triggering organisms .
• Describe the clinical features of Guillain-Barré syndrome and the main types.
• Recognize the complications of the syndrome.
• List investigations to differentiate it from other causes of muscle weakness.
• Outline of the treatment modalities.
• Post-infectious polyneuropathy
– Mainly motor nerves.
– Sometimes also sensory and autonomic nerves.
• Any age
• Most patients have a demyelinating neuropathy
– Primarily axonal degeneration
• Usually follows a nonspecific viral infection by about 10 days. – Gastrointestinal
• Campylobacter jejuni, Helicobacter pylori
– Respiratory tract • especially Mycoplasma pneumoniae
• Reported following administration of vaccines – Rabies – Influenza – Poliomyelitis (oral) – Conjugated meningococcal vaccine (serogroup C).
CLINICAL MANIFESTATIONS
• Landry ascending paralysis.
• Proximal and distal muscles are involved relatively symmetrically.
– 9% Asymmetry
• Tendon reflexes are lost, usually early in the course, but are sometimes preserved until later.
– This variability can cause confusion.
• The onset: gradual
– progresses over days or weeks.
• Cases with an abrupt onset
– tenderness on palpation and pain in muscles is common in the initial stages.
• Weakness can progress →inability or refusal to walk → flaccid tetraplegia.
• Paresthesias: some cases.
• Bulbar involvement occurs in about half of cases.
– Respiratory insufficiency can result.
• Dysphagia and facial weakness are often impending signs of respiratory failure.
– Extraocular muscle involvement is rare
Miller-Fisher syndrome
• Acute external ophthalmoplegia
• Ataxia
• Areflexia.
– Overlaps with Bickerstaff brainstem encephalitis
• Shares many features with Guillain-Barré syndrome with lower motor neuron involvement
• The autonomic nervous system is also involved in some cases.
– Labiality of blood pressure and cardiac rate
– Postural hypotension
– Episodes of profound bradycardia
– Occasional asystole
• Cardiovascular monitoring is important.
DIFFERENTIAL DIAGNOSIS
SPINAL CORD LESIONS • Acute transverse myelitis • Epidural abscess • Tumors • Poliomyelitis • Hopkins syndrome • Vascular malformations • Cord infarction • Fibrocartilaginous embolism • Cord compression from vertebral
subluxation related to congenital abnormalities or trauma
• Acute disseminated encephalomyelitis
PERIPHERAL NEUROPATHIES
• Toxic – Vincristine
– Glue sniffing
– Heavy metal
– Organophosphate pesticides
• Infections – HIV
– Diphtheria
– Lyme disease
DIFFERENTIAL DIAGNOSIS
PERIPHERAL NEUROPATHIES
• Inborn errors of metabolism – Leigh disease
– Tangier disease
– Porphyria
• Critical illness: polyneuropathy/myopathy
NEUROMUSCULAR JUNCTION DISORDERS
• Tick paralysis
• Myasthenia gravis
• Botulism
• Hypercalcemia
• Myopathies
• Periodic paralyses,
• Dermatomyositis
• Critical illness myopathy/polyneuropathy
Work up
• Serum creatine kinase (CK) – may be mildly elevated or normal
• CSF studies are essential for diagnosis. – protein is elevated to more than twice the upper
limit of normal
– Glucose level is normal
– No pleocytosis. • Fewer than 10 white blood cells/mm3 are found.
– Bacterial cultures are negative
• Serologic testing for Campylobacter and Helicobacter infections helps establish the cause
– does not alter the course of treatment.
• Results of stool cultures are rarely positive
– The infection is self-limited (occurs for about 3 days), and the neuropathy follows the acute gastroenteritis.
MRI
• Of the spinal cord may be indicated to rule out disorders.
• MRI findings include thickening of the cauda equina and intrathecal nerve roots with gadolinium enhancement.
– These finds are fairly sensitive and are present in >90% of patients
NCS
• Motor NCVs are greatly reduced
• Sensory nerve conduction time is often slow.
• Electromyography (EMG) shows evidence of acute de-nervation of muscle.
Antiganglioside antibodies
• Mainly against GM1 and GD1
• Sometimes elevated in the serum in Guillain-Barré syndrome, particularly in cases with primarily axonal rather than demyelinating neuropathy
TREATMENT
• In early stages of this acute disease
– Should be admitted to the hospital for observation because the ascending paralysis can rapidly involve respiratory muscles during the next 24 hr
– Respiratory effort (negative inspiratory force, spirometry) must be monitored to prevent respiratory failure and respiratory arrest.
• slow progression – observation for stabilization – spontaneous remission without treatment possible
• Rapidly progressive ascending paralysis – Intravenous immunoglobulin (IVIG), administered for
2, 3, or 5 days. • A commonly recommended protocol is IVIG 0.4 g/kg/day for
5 consecutive days.
– Plasmapheresis and/or immunosuppressive drugs • if IVIG is ineffective.
– Steroids are not effective.
Supportive care
• Respiratory support
• Prevention of decubiti in children with flaccid tetraplegia
• Treatment of secondary bacterial infections
PROGNOSIS
• Usually, spontaneous recovery begins within 2-3 wk.
• Most patients regain full muscular strength • The tendon reflexes are usually the last function
to recover. • Improvement usually follows a gradient opposite
the direction of involvement: • Bulbar and respiratory muscle involvement can
lead to death if the syndrome is not recognized and treated.
• 3 clinical features are predictive of poor outcome with sequelae:
– Cranial nerve involvement
– Intubation
– Maximum disability at the time of presentation.
• The electrophysiologic features of conduction block are predictive of good outcome.
• Easy fatigue is one of the most common chronic symptoms
• Among patients with the axonal form of Guillain-Barré syndrome, most who had slow recovery over the first 6 mo could eventually walk, although some required years to recover.
• EMG and NCV electrophysiologic studies do not necessarily predict the long-term outcome.
Chronic inflammatory demyelinating polyradiculoneuropathies
• (CIDP, sometimes called chronic inflammatory relapsing polyneuritis or chronic unremitting polyradiculoneuropathy) – Chronic varieties of Guillain-Barré syndrome
• Recur intermittently
• Do not improve
• Progress slowly and relentlessly for periods of months to years.
• About 7% of children with Guillain-Barré syndrome suffer an acute relapse.