Pathophysiology of conduction block in neuromuscular diseases

Česká verzia

Authors: E. Ehler ¹; I. Štětkářová ²
Authors place of work: Neurologické oddělení, Pardubická krajská nemocnice, a. s. ¹; Neurologické oddělení, Nemocnice Na Homolce, Praha ²
Published in the journal: Cesk Slov Neurol N 2008; 71/104(2): 139-147
Category: Review Article

Summary

Polarization of axonal membrane is necessary for impulse conduction in peripheral nerve fibers. Smooth functioning of ion channels is responsible for proper excitability of axonal membrane. In myelinated fibers there is possibility to differentiate various regions of one segment: nodal, paranodal, juxtaparanodal and internodal. Among the most frequent sodium channels there are 3 types with the highest occurrence in the nodal region. Potassium channels can be divided into 3 voltage-operated subtypes. Appearance of fast K⁺ channels is limited to juxtaparanodal segment. Testing of ion channels and membrane excitability is possible with double-stimulation technique or with the electrotonus threshold assessment. Conduction block can be divided into „activity dependent“ and „activity independent“. We present patients with chronic demyelinating polyneuritis, multifocal motor neuropathy and compressive mononeuropathy as clinical case reports.

Key words:
conduction block – excitability of membrane – ion channels – threshold electrotonus

Zdroje

1. Bostock H, Cikurel K, Burke D. Threshold tracking techniques in the study of human peripheral nerve. Muscle Nerve 1998; 21: 137–158.

2. Nodera H, Kaji R. Nerve excitability testing and its clinical application to neuromuscular diseases. Clin Neurophysiol 2006; 117: 1902–1916.

3. Kuwabara S, Kanai K, Sung JY, Ogawara K, Hattori T, Burke D et al. Axonal hyperpolarization associated with acute hypokalemia: multiple excitability measurements as indicators of the membrane potential of human axons. Muscle Nerve 2002; 26: 283–287.

4. Ganong WF. Přehled lékařské fyziologie. Jinočany: H&H 1999.

5. Bednařík J et al. Nemoci kosterního svalstva. Praha: Triton 2001.

6. Krarup C. Physiology and function. In: Kimura J (Ed). Peripheral nerve diseases. Edinburgh – London: Elsevier 2006: 23–61.

7. Brown WF. Transmembrane potential and action potential. In: Brown WF, Bolton CHF, Aminoff MJ (Eds). Neuromuscular function and disease. Philadelphia: WB Saunders 2002: 1–20.

8. Al-Shekhlee AA, Hachwi RN, Preston DC, Katirji B. New criteria for early electrodiagnosis of acute inflammatory demyelinating polyneuropathy. Muscle Nerve 2005; 32: 66–72.

9. Kuwabara S, Ogawara K, Sung JY, Mori M, Kanai K, Hattori T et al. Differences in membrane properties of axonal and demyelinating Guillain-Barré syndromes. Ann Neurol 2002; 52: 180–187.

10. van den Bergh PY, Piéret F. Electrodiagnostic criteria for acute and chronic inflammatory demyelinating polyradiculoneuropathy. Muscle Nerve 2004; 29: 565–574.

11. Weber F, Rüdel R, Aulkemeyer P, Brinkmeier H. Anti-GM1 antibodies can block neuronal voltage-gated sodium channels. Muscle Nerve 2000; 23: 1414–1420.

12. Cappelen-Smith C, Kuwabara S, Lin CS, Mogyoros I, Burke D. Activity-dependent hyperpolarization and conduction block in chronic inflammatory demyelinating polyneuropathy. Ann Neurol 2000; 48: 826–832.

13. Mohamed A, Davies L, Pollard JD. Conduction block in vasculitis neuropathy. Muscle Nerve 1998; 21: 1084–1088.

14. Priori A, Bossi B, Ardolino G, Bertolasi L, Carpo M, Nobile-Orazio E et al. Pathophysiological heterogeneity of conduction blocks in multifocal motor neuropathy. Brain 2005; 128: 1642–1648.

15. Ambler Z. Poruchy iontových kanálů. Cesk Slov Neurol N 2000; 63/96: 203–208.

16. Benatar M, Willison HJ, Vincent A. Immune-mediated peripheral neuropathies and voltage-gated sodium channels. Muscle Nerve 1999; 22: 108–110.

17. Vucic S, Dawson K, Sun D, Cros D. Pure motor mononeuropathy with distal conduction block: an unusual presentation of multifocal motor neuropathy with conduction blocks. Clin Neurophysiol 2004; 115: 2323–2328.

18. Deroide N, Uzenot D, Verschueren A, Azulay JP, Pouget J, Attarian S. Triple-stimulation technique in multifocal neuropathy with conduction block. Muscle Nerve 2007; 35: 632–636.

19. Watson BV, Nicolle MW, Brown JD. Conduction block in neuralgic amyotrophy. Muscle Nerve 2001; 24: 559–563.

20. Kaji R, Bostock H, Kohara N, Murase N, Kimura J, Shibasaki K. Activity-dependent conduction block in multifocal motor neuropathy. Brain 2000; 123: 1602–1611.

21. Priori A, Bossi B, Ardolino G, Bertolasi L, Carpo M, Nobile-Orazio E et al. Pathophysiological heterogeneity of conduction blocks in multifocal motor neuropathy. Brain 2005; 128: 1642–1648.

22. Watson BV, Brown WF, Doherty TJ. Frequency-dependent conduction block in carpal tunnel syndrome. Muscle Nerve 2006; 33: 619–626.