periphral neuropathy

Question 1

what is peripheral neuropathy

Answer 1

damage to the nerves outside the CNS; can be sensory, motor or both

Question 2

examples of causes of chronic peripheral neuropathy (5)

Answer 2

1. diabetes
2. alcoholism
3. low B12
4. physical damage
5. hypothyroidism

Question 3

examples of sensory abnormalities seen in peripheral neuropathy

Answer 3

positive symptoms - parasthesia, pain;
negative symptoms - numbness

can be constant or intermittant

Question 4

examples of motor abnormalities seen in peripheral neuropathy

Answer 4

loss of function -> weakness (distal > proximal), cramps (loss of activity to muscle)

Question 5

what distribution is seen in peripheral neuropathy

Answer 5

glove and stocking - longest nerves are most vulnerable -> toes affects first

Question 6

what is the most common mononeuropathy

Answer 6

carpel tunnel

Question 7

presentation of vascular peripheral neuropathy

Answer 7

patchy; acute onset; severe pain with loss of function

Question 8

what is a common infective cause of peripheral neuropathy

Answer 8

leprosy

Question 9

what surgery may result in a peripheral neuropathy

Answer 9

hip replacement -> damage to common peroneal leads to foot drop

Question 10

2 autoimmune peripheral neuropathy conditions

Answer 10

1. guillain -barre (acute onset)
2. chronic inflammatory demyelinating polyneuropathy (CIDP)

Question 11

what does NOs usage lead to and why (neuropathy)

Answer 11

length dependent generalised neuropathy

NOs inhibits the activity of B12 -> B12 deficiency -> build up of toxic products in haem synthesis

Question 12

what cancer can often lead to peripheral neuropathy

Answer 12

sc lung cancer

Question 13

what is the commonest congenital peripheral neuropathy

Answer 13

Charcot-Marie-Tooth disease -> type 1 (myelin) or type 2 (axonal)

Question 14

what is the mutation associated with charcot-marie-tooth disease type 1

Answer 14

PMP22 gene duplication -> build up of PMP22 protein

Question 15

what is Hereditary Neuropathy with liability to Pressure Palsies

Answer 15

an inherited condition that causes acute onset paresthesia, numbness etc. when leaning on a nerve

Question 16

what mutation is seen in Hereditary Neuropathy with liability to Pressure Palsies

Answer 16

PMP22 deletion

Question 17

investigations for peripheral neuropathy (6)

Answer 17

1. nerve conduction studies;
2. FBC (macrocytosis is a sign of B12 deficency);
3. biochem;
4. Hba1c;
5. immunology/serology (paraproteins);
6. Lumbar puncture (look for increased protein levels in CSF)