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