Polyneuropathy Flashcards
What are polyneuropathies?
Motor and or sensory disorder of multiple peripheral or cranial nerves
Usually symmetrical, widespread and often worse distally (‘glove and stocking’)
How can polyneuropathies be classified?
Chronicity
Function (sensory, motor, autonomic or mild)
Pathology (demyelination, axonal degeneration or both)
What should you ask about in polyneuropathy?
Time course Nature of symptoms Preceding or associated events (e.g. D/V before Guillan Barre, weight loss in cancer) Travel Alcohol/drug use Sexual infections Family history
What is the function of nerve conduction stidies?
Distinguish demyleinating from axonal causes
what investigations in polyneuropathy?
FBC ESR Gluose U/E LFT TSH B12 Electophoresis ANA ANCA CXR Urinalysis
What are causes of predominantly sensory neuropathy?
Diabtes Uraemia ( CKD Leprosy Alcoholism B12 deficiency Amyloidosis
Describe sensory neuropathy.
Numbness Pins and needles Paraesthesiae Glove and stocking distribution Difficulty handling small objects Signs of trump (finger burns or joint deformation)
DM and alcohol are painful
What are causes of motor neuropathies?
Guillain Barre syndrome
Porphyria
Lead poisoning
Hereditary sensorimotor neuropathies - Charcot-Marie-Tooth
Chronic infelammatory demylinating polyneuropathy
Diphtheria
Describe motor neuropathy
Progressive
Weak or clumsy hands
Difficulty in walking - falls
Difficulty in breathing (reduced vital capacity)
LMN lesion
Wasting and weakness most in distal muscles o hands and feet
Hyporeflexia
What do you get in cranial nerve neuropathies?
Swallowing/speaking difficulty
Diplopia
What causes alcoholic neuropathy?
Toxic effects and reduced absorption of B vitamins
Sensory symptoms present prior to motor
What can B12 deficiency cause?
Subacute combined degeneration of the spinal cord
Dorsal column affected first (joint position and vibration) prior to distal paraesthesia
What is Guillain Barre syndrome? Features?
Immune mediaed demyelination of the peripheral nerves often triggered by infection - Campylobacter jejuni
Peripheral neuropathy (motor) preceded by D/V
Progressive weakness of all four limbs
Weakness is classically ascending - LL first - however proximal muscles earlier than distal
Sensory symptoms mild
Can be: Areflexia Cranial nerve involvement Autonomic involvement Anti-GM1 antibodies
What is Miller Fisher syndrome?
Guillain Barre variant, associated with: Ophthalmoplegia Areflexia Ataxia Eye muscles are affected first Descending paralysis
What is HSMN?
Hereditary sensorimotor neuropathy - Charcot-Marie- Tooth
Peroneal msucular atrophy
Type 1 - demyelinating
- autosomal dominany
- Start at puberty
- Motor symptoms predominante
- distal muscle wasting, clawed toes, foot drop, leg weakness
Type 2 - axonal