PMID- 31536037 OWN - NLM STAT- MEDLINE DCOM- 20200904 LR - 20211025 IS - 1877-8879 (Electronic) IS - 1877-8860 (Linking) VI - 20 IP - 1 DP - 2019 Dec 18 TI - Pain and small-fiber affection in hereditary neuropathy with liability to pressure palsies (HNPP). PG - 61-68 LID - 10.1515/sjpain-2019-0090 [doi] AB - Background and aims Hereditary neuropathy with liability to pressure palsies (HNPP) is an autosomal - dominant hereditary neuropathy caused by a deficiency in the peripheral protein PMP-22, due to deletion on chromosome 17p11,2 or in some rare cases point mutations in the PMP-22 gene. The clinical picture is characterized by recurrent mononeuropathies in nerves which frequently may be exposed to pressure, such as the median, ulnar, radial and peroneal nerves or also a more general neuropathy. Although pain is reported to be an unusual clinical symptom, there have been reports of pain in a surprisingly high proportion of these patients. Since pain may be explained by mechanisms in afferent small unmyelinated C- nerve fibers, an assessment of the function of small nerve fibers has been requested. The purpose of the present study was to investigate the presence of pain and the possible affection of afferent small nerve-fibers, A-delta and C-fibers, by quantitative sensory testing (QST)-assessment of thermal thresholds, as well as quantitative sudomotor axon reflex (QSART), a quantitative, validated assessment of efferent postganglionic sumodotor function. QST values were compared to values of age- and sex matched healthy subjects. Methods The 19 patients were investigated clinically, with an emphasis on pain characteristics, with nerve conduction studies (NCS) of major nerves in upper- and lower extremity, small fiber testing (QST, measurement of thermal thresholds) and with QSART. Results A total of 10 patients reported numbness in some extremity, suggesting entrapment of individual nerves as well as a general neuropathy, as verified by NCS in nine patients. A total of 15 patients had findings compatible with a general polyneuropathy. A total of eight patients reported pain, seven patients with pain in the feet, described as burning, aching, shooting and six with severe pathological QST values, mainly cold detection, but also four patients with elevated thresholds to warmth. Four of the patients had signs of a severe sensory neuropathy on NCS, with no sural findings. One patient had only pain in the arms, with only minor changes on NCS and with normal QST-values. Cold detection thresholds (CD) were significantly elevated (reduced sensibility) on the dorsum of the foot (mean of two feet), in patients [26.0 degrees C (19.7-28.0)] as compared with healthy subjects [28.6 degrees C (27.4-29.6) p = 0.000]. There were also significantly elevated warmth detection thresholds (WD) in feet in patients 39.5 degrees C (36.4-42.9) compared to healthy subjects [37.7 degrees C (36.1-39.4) p = 0.048]. However, there were no significant differences in QST values between patients with and without pain. Conclusions Of a total of 19 patients with verified HNPP, eight patients (42.1%) suffered from neuropathic pain, mainly in both feet. Implications Due to the high percentage of pain in HNPP, it is important not to disregard this diagnosis in a patient presenting with pain. Since there are no significant differences in QST values in patients with and without pain, routine QST studies in HNPP do not seem necessary. FAU - Dukefoss, Tore Thomas AU - Dukefoss TT AD - Section of Clinical Medicine, The Department of Neurology, Sykehuset Innlandet Trust, Lillehammer, Norway. FAU - Kleggetveit, Inge Petter AU - Kleggetveit IP AD - Section of Clinical Neurophysiology, The Department of Neurology, Oslo University Hospital - Rikshospitalet, Oslo, Norway. FAU - Helas, Tormod AU - Helas T AD - Section of Clinical Neurophysiology, The Department of Neurology, Telemark Hospital Trust, Skien, Norway. FAU - Jorum, Ellen AU - Jorum E AD - Section of Clinical Neurophysiology, The Department of Neurology, Oslo University Hospital - Rikshospitalet, Institute of Clinical Medicine, University of Oslo, Oslo, Norway. LA - eng PT - Journal Article PT - Research Support, Non-U.S. Gov't PL - Germany TA - Scand J Pain JT - Scandinavian journal of pain JID - 101520867 RN - 0 (Myelin Proteins) RN - 0 (PMP22 protein, human) RN - Tomaculous neuropathy SB - IM MH - Adult MH - Arthrogryposis/*genetics MH - Female MH - Foot MH - Hereditary Sensory and Motor Neuropathy/*genetics MH - Humans MH - Hypesthesia/etiology MH - Male MH - Myelin Proteins/*deficiency MH - Neural Conduction/*physiology MH - Neuralgia/*physiopathology MH - Neurons, Afferent/*physiology MH - Pain/*physiopathology OTO - NOTNLM OT - hereditary neuropathy with liability to pressure palsies (HNPP) OT - nerve conduction studies OT - pain OT - quantitative sensory testing OT - small fiber affection EDAT- 2019/09/20 06:00 MHDA- 2020/09/05 06:00 CRDT- 2019/09/20 06:00 PHST- 2019/06/27 00:00 [received] PHST- 2019/08/20 00:00 [accepted] PHST- 2019/09/20 06:00 [pubmed] PHST- 2020/09/05 06:00 [medline] PHST- 2019/09/20 06:00 [entrez] AID - sjpain-2019-0090 [pii] AID - 10.1515/sjpain-2019-0090 [doi] PST - ppublish SO - Scand J Pain. 2019 Dec 18;20(1):61-68. doi: 10.1515/sjpain-2019-0090.