|
|
|
© Dirk Biddle
A nerve biopsy may be performed to help distinguish between demyelination (destruction of parts of the myelin sheath covering the nerve) and axon degeneration (destruction of the axon portion of the nerve cell), to identify inflammatory nerve conditions (neuropathies), or to confirm specific diagnoses.
Where nerve involvement is evident or suspected (for example in the case of a necrotising vasculitis), a biopsy of the sural nerve, in the leg and ankle (or the superficial radial nerve in the wrist), may be conducted. The sural nerve runs alongside the calf muscle at the back of the leg and is a sensory nerve, thus the removal of a section will not impair motor function of the muscle or foot. The skin is opened under local anaesthetic and a section of the sural nerve (5-10cm) is removed and the skin sewn back together with 10-20 stitches. There may be some residual numbness, which is usually tolerated well. However if the vasculitis condition is severe enough, numbness may already be present.
Conditions or disorders that may be revealed by nerve biopsy include: Necrotising vasculitis, Amyloidosis (sural nerve biopsy is most often used), Sarcoidosis, Leprosy, Metabolic neuropathies, Inflammation of the nerve, Loss of axon tissue and Demyelination. Additional conditions under which the test may be performed include Alcoholic neuropathy, Axillary nerve dysfunction, Brachial plexopathy, Charcot-Marie-Tooth disease (hereditary), Common peroneal nerve dysfunction, Distal median nerve dysfunction, Mononeuritis multiplex, Mononeuropathy, Necrotising vasculitis, Neurosarcoidosis, Radial nerve dysfunction and Tibial nerve dysfunction (1).
-------------------------
1) http://www.nlm.nih.gov/medlineplus/ency/article/003928.htm
| back |