Peripheral neuropathy in children

• A functional disturbance or pathological change in the peripheral nervous system

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

• Urinary incontinence or retention of urine: 20% of cases

– Usually transient

• 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.

Classification of Guillain-Barre syndrome and related disorders

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

biopsies

• Muscle and nerve is not usually required for the diagnosis

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.