Diagnostic yield by testing small fiber function in patients examined for polyneuropathy.
We assessed the diagnostic yield of adding quantitative sensory testing to the standard work-up for polyneuropathy in unselected patients. All patients aged 18 to 70 years referred to our department for electrodiagnosis with a tentative diagnosis of polyneuropathy and symptoms complying with predefined criteria were included in the study. We performed near nerve conduction studies in 4 nerves and determined heat and cold detection thresholds on hand and foot with a Thermotest (Somedic AB, Sweden). In order to uncover CNS diseases, somatosensory-evoked potentials were recorded in patients with abnormal quantitative sensory testing and normal nerve conduction studies. A total of 198 patients completed the study and 149 were considered to have polyneuropathy. Twenty-five patients remained undiagnosed and in 24 patients, other diseases were responsible for the symptoms. Of the patients with either polyneuropathy or no other diagnosis, 76% (n = 174) had abnormal nerve conduction. Abnormal cold sensation, heat sensation or abnormality in at least 1 of these and normal nerve conduction were found in 14, 12 and 17 patients. Of the 174 patients, 86% (95% CI 80-90%) had an abnormality in at least 1 of the tests (i.e. abnormal nerve conduction and/or abnormal quantitative testing of temperature sensation). In conclusion, quantitative testing of temperature sensation improves the diagnostic yield in patients examined for chronic polyneuropathy.
Sindrup
S H
SH
Department of Neurology, Odense University Hospital, Denmark. s.sindrup@dadlnet.dk
Gaist
D
D
Johannsen
L
L
Havsager
A M
AM
Homburg
A
A
Kjeldsen
M J
MJ
Madsen
C
C
Dalsgaard
N J
NJ
Ellemann
K
K
Smith
T
T
D000328:Adult; D000368:Aged; D000842:Ankle / Q000503:physiopathology; D003080:Cold Temperature; D005073:Evoked Potentials, Somatosensory; D005260:Female; D006358:Hot Temperature; D006801:Humans; D008297:Male; D008875:Middle Aged; D009412:Nerve Fibers / Q000502:physiology; D009431:Neural Conduction; D011115:Polyneuropathies / Q000175:diagnosis* / Q000503:physiopathology; D011237:Predictive Value of Tests; D012680:Sensitivity and Specificity; D012684:Sensory Thresholds; D013697:Thermosensing