Slide on approach to peripheral neuropathy

2.  Refers to nerves outside
the brain and spinal
cord.
 Broken down into
 Sensory
 Motor
 Autonomic
▪ Parasympathetic
▪ Sympathetic

4.  Neuropathies might be acute or chronic
 Mononeuropathy – affecting a single nerve
 Polyneuropathy – diffuse, symmetrical disease
usually starting peripherally.
 Mononeuritis multiplex – affects several or
multiple nerves.
 Radiculopathy – disease affecting nerve roots
 Peripheral Neuropathy can affect:
 Sensory pathways
 Motor pathways
 Autonomic pathways

5.  Neuropraxia
 Axonotmesis
 Neurotmesis

6.  There are 6 possible mechanisms of
peripheral nerve degeneration
 Demyelination – e.g. Guillain-Barre Syndrome
 Axonal degeneration - e.g. toxic neuropathies
 Wallerian degeneration
 Compression – e.g. carpal tunnel syndrome
 Infarction – e.g. diabetes
 Infiltration – e.g. leprosy and granulomas

7. The causes of peripheral
neuropathy are often
unknown but the two
main causes are:
 Diabetic Neuropathy
 Nutritional, including
alcohol (B1 deficiency)

8.  Other causes
 Infection – HIV, leprosy, diptheria, tetanus, botulism
 Heavy metal poisoning e.g. Lead and mercury
 Malignancy
 Metabolic – hypothyroidism, liver failure, renal failure
 Postinfective polyneuritis – Guillain-Barre Syndrome
 Sarcoidosis
 Drugs – isoniazid, vincrinstine, phenytoin, gold,
excess vitamin B6
 Congenital – Charcot-Marie Tooth syndrome

9.  Pneumonic to remember DAVID:
 Diabetes
 Alcoholism
 Vitamin deficiency – B12
 Infective/inherited – Guillain-Barre
 Drugs – e.g. isoniazid

10.  Peripheral nerve compression and
entrapment
 Carpal tunnel syndrome is a common
mononeuropathy – Median nerve
entrapement
 Clinical presentation
 Pain, tingling and paraesthesia on
palmar aspect of hand and fingers
 Weakness of thenar muscles and
wasting of abductor pollicis brevis
 Nocturnal
 Pain may extend to arm and shoulder
 Tinel’s and Phalen’s tests are positive.

11.  Paraesthesia
 Numbness
 Burning pain
 Loss of vibration sense and
position sense
 Difficulty using small
objects e.g. needles
 Subacute with ataxia due
to loss of sense of posture
 Feet are usually affected
first – Sock and Glove

12.  Clinical Presentation:
 Postural hypotension
 Urinary retention
 Erectile dysfunction
 Diarrhoea/constipation
 Diminished sweating
 Impaired pupillary response
 Cardiac arrhythmias
 Might occur in:
 Diabetes
 Amyloidosis
 Guillain-Barre syndrome

13.  Clinical presentation:
 Progressive weakness or clumsiness
 Difficulty walking (falling or stumbling)
 Respiratory difficulties (falling vital capacity)
 Wasting
 Foot or wrist drop might be seen
 Reflexes absent or reduced

14.  Directly related to the duration and degree of
abnormal metabolic control – occurring relatively
early in disease
 Due to metabolic disturbance and accumulation of
fructose and sorbitol in Scwann cells  degradation
 Types of Diabetic neuropathy
 Symmetrical mainly sensory neuropathy
 Acute painful neuropathy
 Mononeuropathy and mononeuritis multiplex
 Diabetic amyotrophy
 Autonomic Neuropathy

15.  Chronic alcohol abuse leads
to polyneuropathy
 Calf pain is common
 Deficiency in thiamine due to
alcoholism also causes
neuropathy
 Can lead to Wernicke-Korsakoss
syndrome
 Common presentation
▪ Eye signs
▪ Ataxia
▪ Cognitive change
▪ Delirium tremens
▪ Hypothermia and hypotension

16.  Acute polyneuropathy – acute inflammatory or postinfective
neuropathy
 Usually demyelinating but can be axonal
 Monophasic – following Campylobacter jejuni and CMV
infections
 Infection induces antibody responses against peripheral nerves
 Paralysis 1-3 weeks following infection
 Weakness of distal limb muscles and/or distal numbness
 Symptoms progress proximally
 Loss of tendon reflexes
 Facial muscle weakness
 Autonomic features - uncommon
 Might need ventilatory support
 SC heparin is required to reduce risk of thrombosis
 Spontaneous recovery begins after several weeks

17.  Cancer - Paraneoplastic syndrome, sometimes
with anti-neuronal antibodies
 Polyarteritis nodusa
 Sarcoidosis
 Giant cell arteritis
 Rheumatoid disease
 Vitamin B12 defeciency
 Charcot-Marie-Tooth disease
 Thyroid disease
 Uraemia
 Cranial polyneuropathy

18.  Urine – glucose, protein
 Haematology – FBC, ESR, vitamin B12, folate
 Biochemistry – fasting glucose, RFT, LFT,
TSH
 Neurophysiology testing
 Nerve conduction studies
 Needle electromyography
 Nerve biopsy

19.  Need to find cause of neuropathy to treat
 If pain can give antiepileptic, antidepressant
drugs or tramadol.
 Foot care – good shoes
 Weight reduction
 Walking aids for those with severe leg
weakness
 Occupational therapy
 Physiotherapy

20.  Images from Google Images and Kumar and
Clark