Peripheral neuropathy Flashcards
What percentage of alcoholics have peripheral neuropathy per EMG findings?>
25-66%
What is the natural history of peripheral neuropathy related to etoh?
Length dependent neuropathy
Initially pain, followed by increasing sensory loss then weakness
What are the clinical features of B12 deficiency associated neuropathy?
Sudden onset
Concomitant involvement of upper and lower limbs at onset
Painless, sensory-dominant neuropathy with absent ankle jerk reflexes
Explained by concomitant myelopathy and peripheral neuropathy
MRI shoes hyperintense lesions in dorsal column
Associated with hyperpigmentation of knuckles
What is more sensitive for assessment of paraproteins; serum protein electrophoresis or serum immunofixation electrophoresis?
serum immunofixation electrophoresis
What is the most common cause of peripheral neuropathy?
Diabetic (followed by nutritional deficiency and alcohol)
What are the metabolites of B12 that are recommended to be tested for in low-normal B12 levels?
MMA and homocystine
What are the GBS variants?
Classic sensorimotor
Pure motor
Paraparetic (sensorimotor)
Bilateral facial palsy with paraesthesias
Pure sensory
Pharyngeal-cervical-brachial (sensorimotor)
Miller-fisher syndrome - eyes and cerebellar dysfunction
Bickerstaff brainstem encephalitis - CNS variant
Negative symptoms of neuropathy
Motor: weakness
Sensory: numbness, sensory ataxia, inability to differentiate between hot and cold
What does CIDP stand for?
Chronic inflammatory demyelinating polyradiculoneuropathy
Approach to peripheral neuropathy
Time: onset, duration Motor / sensory / both Large / small fibre Single nerve / multiple single nerves / polyneuropathy Axonal process vs demyelination
What is mononeuritis multiplex?
A mononeuropathy which happens in step-wise fashion (one nerve, then another)
Autonomic symptoms of neuropathy
GI: bloating, early satiety, diarrhoea, constipation
GU: impotence, urinary incontinence
CV: postural dizziness, cold extremities, hyperhydrosis / anhydrosis
Positive symptoms of neuropathy
Motor: cramps, twitching
Sensory: pain, paraesthesia, allodynia, hyperesthesia
What is the prevalence of peripheral neuropathy?
2-8%
What are the differences between demyelinating injury and axonal injury?
Demyelinating injuries:
inherited or inflammatory; can involve nerve roots / trunks resulting in proximal weakness, patchy involvement with rapid and complete recovery (in inflammatory causes)
Axonal injury:
Cause “dying back” of nerve distal to injury = “Wallerian degeneration”; often length dependent.
Are motor or sensory neuropathies more common?
Sensory
Are positive neuropathic sensory symptoms more or less common in inherited neuropathies?
less common
Carpal tunnel syndrome
- cause
- exacerbating factors
- sensory pattern ?involves palm?
Entrapment of median nerve at the wrist between flexor tendons and flexor retinaculum
Results in pain and paraesthesias, usually worse at night or with use
Sensory loss spares palm
What is Anti-Hu associated with?
Paraneoplastic neuropathy (sensory)
Treatment for carpal tunnel
Carpal splint, steroids, surgical management
What is albumino-cytologic dissociation?
In CSF: increased total protein concentration with normal total nucleated cell count. Seen in GBS.
What is the typical presentation of CIDP?
symmetrical, motor-prodominant, proximal and distal, areflexic
relapsing or progressive >8 weeks
What percentage of peripheral neuropathy remain cryptogenic following extensive work up?
20% remain cryptogenic
