Immune-mediated myositis in Crohn's disease.

We report a patient with uncontrolled Crohn's disease who presented with progressive weakness of proximal muscles and a marked elevation of serum creatine kinase. Muscle biopsy from the left deltoid exhibited myositic changes with inflammatory infiltrates in the perimysium, endomysium, and perivascular locations. Most were stained as CD68-positive macrophages, whereas some were CD4- and CD8-positive T lymphocytes. Due to uncontrolled bowel inflammation, several fistulae were found in the descending colon, and partial colectomy was performed. An examination of the resected colon exhibited inflammation of the bowel structure surrounded mainly by CD68-positive macrophages. The histopathological findings of the descending colon were analogous to those of the muscle. After an increased dose of mesalazine and partial colectomy, her muscle symptoms improved. These findings suggest that the myositis in Crohn's disease is immune-mediated and that treatment of bowel inflammation should be emphasized as opposed to steroid or other immunosuppressive therapy.

Electrophysiological studies on human pain perception.

OBJECTIVE: We reviewed the recent progress in electrophysiological studies using electroencephalography (EEG), magnetoencephalography (MEG) and repetitive transcranial magnetic stimulation (rTMS) on human pain perception. METHODS: For recording activities following A delta fiber stimulation relating to first pain, several kinds of lasers such as CO2, Tm:YAG and argon lasers are now widely used. The activity is frequently termed laser evoked potential (LEP), and we reviewed previous basic and clinical reports on LEP. We also introduced our new method, epidermal stimulation (ES), which is useful for recording brain activities by the signals ascending through A delta fibers. For recording activities following C fiber stimulation relating to second pain, several methods have been used but weak CO2 laser stimuli applied to tiny areas of the skin were recently used. RESULTS: EEG and MEG findings following C fiber stimulation were similar to those following A delta fiber stimulation except for a longer latency. Finally, we reviewed the effect of rTMS on acute pain perception. rTMS alleviated acute pain induced by intracutaneous injection of capsaicin, which activated C fibers, but it enhanced acute pain induced by laser stimulation, which activated A delta fibers. CONCLUSIONS: One promising approach in the near future is to analyze the change of a frequency band. This method will probably be used for evaluation of continuous tonic pain such as cancer pain, which evoked response studies cannot evaluate.

Effects of 1-Hz repetitive transcranial magnetic stimulation on acute pain induced by capsaicin.

The aim of this study is to investigate the efficacy of 1-Hz repetitive transcranial magnetic stimulation (rTMS) over the primary motor cortex (M1) on acute pain induced by intradermal capsaicin injection and to elucidate its mechanisms by single-photon emission computed tomography (SPECT). We compared time courses of a subjective scale of pain induced by intradermal capsaicin injection in seven normal subjects under three different conditions: rTMS over M1, sham stimulation, and control condition (natural course of acute pain without any stimulation). In ten normal subjects, using SPECT, we also studied differences in regional cerebral blood flow (rCBF) after capsaicin injection between two conditions: rTMS over M1 and the control condition. rTMS over M1 induced earlier recovery from acute pain compared with the sham or control conditions. Under rTMS over the right M1 condition compared with the control condition, the SPECT study demonstrated a significant relative rCBF decrease in the right medial prefrontal cortex (MPFC) corresponding to Brodmann area (BA) 9, and a significant increase in the caudal part of the right anterior cingulate cortex (ACC) corresponding to BA24 and the left premotor area (BA6). A region-of-interest analysis showed significant correlation between pain reduction and rCBF changes in both BA9 and BA24. We conclude that rTMS over M1 should have beneficial effects on acute pain, and its effects must be caused by functional changes of MPFC and caudal ACC.