Peripheral neuropathy

Question 1

What are the causes of large and small fiber neuropathies? How do you investigate them further?

Answer 1

Large fiber neuropathies (e.g guillain barre)

• affects the dorsal column the most (loss of vibration, propioception and joint position sense)-> improportionate
• when patient closes their eyes or in a dark room when they shower-> fall

Small fiber neuropathies (e.g HIV and diabetic neuropathy)

• loss of pain and temperature (common finding is reduced pinprick and temp sensation); glove and stocking pattern
• to further investigate:
• electomyoneurogram and nerve conduction testing
• FBC, U+Es (uraemic neuropathy), blood glucose (diabetic neuropathy), CRP (infectious causes)

Question 2

What are the questions to ask in peripheral neuropathy history? (patient came in with burning toes)

Answer 2

PC:

• onset-acute or chronic
• acute: guillain barre or vasculitis (any changes in the bowel movements or any recent diarrhoea/infection)
• chronic: diabetes mellitus; hereditable neuropathy
• sensory or motor (severity)
• any changes in your feet (pins and needles-> completely numb like you’re walking on cotton wool)
• any changes in temperature
• any weakness in your legs (slightly weak-> find it hard to walk)
• where does it go up to? legs? knees?

PMH/SH:

• check for history of diabetes and are they monitoriing their blood sugar before and after each meal
• what was their latest HBA1C
• have they been referred to the diabetic foot clinic
• any ulcers on your feet
• any surgeries

DH:

FH:

• diabetes mellitus
• charcot marie tooth (hereditable)-> ask for any high arched feet or back problems in family

LH:

• same stuff

Question 3

What are the questions to ask for diabetic patient?

Answer 3

PC:

• check how they have been managing their diabetes
• are they compliant with their medication?do they have a blood sugar diary? have they been recording their blood sugars before and after each meal?
• what was their lastest HbA1C

Check for micro/macrovascular complications:

• diabetic nephropathy-any changes in their waterworks; any bubbles or swelling
• diabetic neuropathy-pins and needles/motor weakness/charcot’s foot (any pain or swelling in the foot)
• diabetic retinopathy-any changes in your vision
• any chest pain/high blood pressure

PMH/SH:

• admissions for DKA or hypoglycaemia-any previous admissions to the hospital for diabetes

DH:

• checking for compliance

FH:

• checking for DM in family

LH/SH:

• same
• offering them support

Question 4

What are the causes of neuropathy? (sensory and motor)

What investigations do you want to do?

Answer 4

Motor causes:

• guillain barre
• charcot marie tooth
• pophryia
• lead poisoning
• diptheria

Sensory causes:

• uraemia
• diabetes
• vitamin B12 deficiency
• alcoholism
• amyloidosis

FBC, BM and HbA1c, U+Es (check for uraemic causes), LFTs (raised GGT for alcoholic causes), serum electrophoresis (amyloidosis), vitamin B12 and folate

electromyoneurogram