Dorsal sural nerve conduction study in vitamin B deficiency with megaloblastic a

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J Peripher Nerv Syst. 2006 Sep;11(3):247-52.

Dorsal sural nerve conduction study in vitamin B deficiency with

megaloblastic anemia.

Turgut B, Turgut N, Akpinar S, Balci K, Pamuk GE, Tekgunduz E, Demir

M.

Department of Medicine, Division of Hematology; and Department of

Neurology, Trakya Medical Faculty, University of Trakya, Edirne,

Turkey.

Peripheral neuropathy is frequently observed in B(12) deficiency. In

spite of this, there is little knowledge about peripheral neuropathy

in B(12) deficiency because the severity of clinical involvement of

the central nervous system clearly outweighs signs and symptoms due

to peripheral nervous system involvement. We primarily investigated

peripheral neuropathy with dorsal sural conduction study, which is a

new method for detection of early peripheral neuropathy, in B(12)

deficiency with megaloblastic anemia.

Conventional nerve conduction studies and tibial sensory-evoked

potential (SEP) recording were also performed. Twenty-eight B(12)-

deficient patients (15 male, 13 female, mean age 65.8 years) with

megaloblastic anemia and 18 age- and sex-matched controls were

included in the study. Although dorsal sural sensory nerve action

potentials (SNAPs) were not recorded in 15 (54%) of 28 patients, only

9 (32%) of them were found to have polyneuropathy by conventional

conduction studies.

Furthermore, patients with dorsal sural SNAP had mean lower

amplitude, mean longer latency, and slower velocity response when

compared with controls. Twenty patients (71%) were diagnosed as

having myelopathy by the combination of tibial SEP and neurological

findings. Two patients whose dorsal sural SNAPs were not recorded had

normal tibial SEP responses; therefore, these patients were

considered to have isolated peripheral neuropathy.

As a result, we conclude that dorsal sural nerve conduction study is

a reliable method for detection of early peripheral neuropathy in B

(12) deficiency.