Perception of electrocutaneous stimuli in irritable bowel syndrome

Prevalence of Fibromyalgia and Chronic Fatigue Syndrome among Individuals with Irritable Bowel Syndrome: An Analysis of United States National Inpatient Sample Database

Background and Aim: Irritable bowel syndrome (IBS) is a functional gastrointestinal disorder associated with other somatic disorders. We studied the prevalence and predictors of fibromyalgia and chronic fatigue syndrome (CFS) in IBS patients. Methods: We used the National Inpatient Sample and included hospitalization of individuals with IBS, using ICD-10 codes, from 2016-2019. The prevalence and predictors of fibromyalgia and CFS in IBS patients were studied. Univariate and multivariate patient- and hospital-level regression models were used to calculate the adjusted odds of fibromyalgia and CFS in the IBS patient population. Results: Of 1,256,325 patients with an ICD-10 code of IBS included in the study, 10.73% (134,890) also had ICD-10 codes for fibromyalgia and 0.42% (5220) for CFS. The prevalence of fibromyalgia and CFS was significantly higher in IBS patients (adjusted odds ratio (AOR) 5.33, 95% confidence interval (CI) 5.24-5.41, p < 0.001, and AOR 5.40, 95% CI 5.04-5.78, p < 0.001, respectively) compared to the general adult population without IBS. IBS-diarrhea, IBS-constipation, and IBS-mixed types were independently associated with increased odds of fibromyalgia and CFS. Increasing age (AOR 1.02, 95% CI 1.01-1.04, p 0.003; AOR 1.02, 95% CI 1.01-1.03, p 0.001), female gender (AOR 11.2, 95% CI 11.1-11.4, p < 0.001; AOR 1.86, 95% CI 1.78-1.93, p < 0.001) and white race (AOR 2.04, 95% CI 1.95-2.12, p < 0.001; AOR 1.69, 95% CI 1.34-2.13, p < 0.001) were independent predictors of increased odds of fibromyalgia and CFS, respectively. Conclusions: It appears that IBS is associated with an increased prevalence of somatic disorders such as fibromyalgia and CFS.

Altered sensorimotor processing in irritable bowel syndrome: Evidence for a transdiagnostic pathomechanism in functional somatic disorders

OBJECTIVE

A recent hypothesis suggests that functional somatic symptoms are due to altered information processing in the brain, with rigid expectations biasing sensorimotor signal processing. First experimental results confirmed such altered processing within the affected symptom modality, e.g., deficient eye-head coordination in patients with functional dizziness. Studies in patients with functional somatic symptoms looking at general, trans-symptomatic processing deficits are sparse. Here, we investigate sensorimotor processing during eye-head gaze shifts in irritable bowel syndrome (IBS) to test whether processing deficits exist across symptom modalities.

METHODS

Study participants were seven patients suffering from IBS and seven age- and gender-matched healthy controls who performed large gaze shifts toward visual targets. Participants performed combined eye-head gaze shifts in the natural condition and with experimentally increased head moment of inertia. Head oscillations as a marker for sensorimotor processing deficits were assessed. Bayes statistics was used to assess evidence for the presence or absence of processing differences between IBS patients and healthy controls.

RESULTS

With the head moment of inertia increased, IBS patients displayed more pronounced head oscillations than healthy controls (Bayes Factor 10 = 56.4, corresponding to strong evidence).

CONCLUSION

Patients with IBS show sensorimotor processing deficits, reflected by increased head oscillations during large gaze shifts to visual targets. In particular, patients with IBS have difficulties to adapt to the context of altered head moment of inertia. Our results suggest general transdiagnostic processing deficits in functional somatic disorders.

Association among Disorders of Gut-Brain Interaction (DGBI) and Fibromyalgia: A Prospective Study

The disorders of gut-brain interaction (DGBI) have been associated with Fibromyalgia (FM). However, there are no data about the relationship between FM and DGBI using Rome IV criteria. This study aimed to evaluate the prevalence of FM in patients with Irritable Bowel Syndrome (IBS) and/or Functional Dyspepsia (FD) and the prevalence of IBS and FD in FM patients using Rome IV criteria. DGBI patients and FM patients were recruited from two outpatient clinics devoted to DGBI and FM. All patients underwent a standardized gastrointestinal (GI) symptoms questionnaire. FM symptoms in DGBI patients were assessed through Fibromyalgia Rapid Screening Tool (FiRST) and Fibromyalgia Impact Questionnaire. Thereafter, the rheumatologists evaluated them. 49.0% of FM patients fulfilled the diagnostic criteria for IBS, 81.6% for FD with an overlap for both IBS/FD in 44.9%. IBS-C was the most prevalent IBS-subtype in DGBI patients, whereas IBS-M was the most prevalent in FM patients (p = 0.01). 45.3% of DGBI patients reported pathological FiRST scores. DGBI patients with FM showed the highest score at the standardized GI questionnaire followed by FM patients with DGBI and DGBI without FM. In conclusion DGBI are common in FM patients and vice versa. The presence of FD is extremely frequent in FM patients. A multidisciplinary approach should be routinely used for the management of these patients.

Food Allergy and Intolerance: A Narrative Review on Nutritional Concerns

Adverse food reactions include immune-mediated food allergies and non-immune-mediated intolerances. However, this distinction and the involvement of different pathogenetic mechanisms are often confused. Furthermore, there is a discrepancy between the perceived vs. actual prevalence of immune-mediated food allergies and non-immune reactions to food that are extremely common. The risk of an inappropriate approach to their correct identification can lead to inappropriate diets with severe nutritional deficiencies. This narrative review provides an outline of the pathophysiologic and clinical features of immune and non-immune adverse reactions to food-along with general diagnostic and therapeutic strategies. Special emphasis is placed on specific nutritional concerns for each of these conditions from the combined point of view of gastroenterology and immunology, in an attempt to offer a useful tool to practicing physicians in discriminating these diverging disease entities and planning their correct management. We conclude that a correct diagnostic approach and dietary control of both immune- and non-immune-mediated food-induced diseases might minimize the nutritional gaps in these patients, thus helping to improve their quality of life and reduce the economic costs of their management.

A systematic review of the association between fibromyalgia and functional gastrointestinal disorders

BACKGROUND

Fibromyalgia and functional gastrointestinal disorders (FGID) including irritable bowel syndrome (IBS) are common conditions presenting in clinical settings and are more prevalent in women. While the relationship between IBS and fibromyalgia has been demonstrated, a review of the prevalence of the broader group of FGID in adults with fibromyalgia has not been undertaken. The aim of this review was to systematically review the published literature, identifying the comorbidity of FGID in people with fibromyalgia, and to discuss the clinical implications, limitations of current research and areas of interest for future research.

METHODS

Medline, Embase, CINAHL and Web of Science were searched during June 2019. Results were screened for original research articles meeting established criteria for identification of FGID in adults diagnosed with fibromyalgia.

RESULTS

A total of 14 studies involving 1340 adults with fibromyalgia, 363 healthy controls and 441 adults with other pathologies were included in this review. Only 1 of the 14 studies included surveyed the full range of FGID . Functional gut disorders were matched to Rome II criteria for reporting and comparison. In addition to increased abdominal pain and functional bloating or gas, IBS of mixed-pattern and constipation-types appear to be more prevalent than diarrhoea-predominant IBS in adults with fibromyalgia.

CONCLUSION

This review confirms previous reports that IBS is common in people living with fibromyalgia and suggests that IBS-mixed and constipation types predominate. An association with a range of FGID other than IBS is suggested, but data are limited. Research exploring the association between fibromyalgia and functional gastrointestinal dysfunction beyond IBS are warranted.

Threshold Electric Skin Sensitivity Fluctuations in Pregnancy, Labor, and Puerperium

Hypothesis: In our clinical study, the stages of pregnancy were independent variables, and the measured change of sensitivity in selected skin areas was the dependent variable. The research hypothesis that the threshold electric skin sensitivity (TESS) fluctuates was based on our previously published research, where the null hypothesis was rejected in similar conditions. Methods: TESS was measured repeatedly in short intervals on the abdomen and right forearm of pregnant and not pregnant women. Results: A statistically very significant change of TESS fluctuation was found between not pregnant and pregnant women in different stages of pregnancy, labor, and postpartum. In the midline above the navel, the TESS fluctuates with similar frequency like intestinal peristalsis and that may reflect on the functional state of the bowels. In both lateral areas of the lower abdomen in not pregnant women and in early pregnancy, we found only minimal TESS fluctuations. They gradually increased until the beginning of labor and then decreased postpartum. In midline above the pubic symphysis, moderate TESS fluctuation in not pregnant women gradually increased during pregnancy, until the beginning of labor and decreased postpartum. TESS fluctuation during labor was not synchronous with recorded uterine contractions. Only minimal TESS fluctuation on the right forearm never changed significantly. Conclusion: TESS fluctuation in midline abdomen may be related to bowel peristaltic motility. In the lateral abdomen and above symphysis, it may be related to uterus activity. TESS measurement in referral pain skin area could be used for functional monitoring of internal organ in the corresponding viscerotome. The measurement of TESS in skin areas and recording fluctuations graphically as an electrosensitogram, could have diagnostic value. As a new noninvasive diagnostic method, electrosensitography could help us better understand the gastrointestinal organ function.

Repeated transcutaneous electrical nerve stimulation of nonspecific acupoints of the upper body attenuates stress-induced visceral hypersensitivity in rats

Irritable bowel syndrome (IBS) is a common stress-related gastrointestinal disorder and visceral hypersensitivity (VH) is characteristically found in IBS patients. Transcutaneous electrical nerve stimulation (TENS) applied to certain acupoints has been shown to benefit IBS patients. Here, we investigated whether nonspecific acupoint is involved in the efficacy of TENS treatment for IBS. Twenty-five male rats were randomly assigned to four experimental groups and one sham-control group. The four experimental groups were defined as TENS-RR, TENS-RL, TENS-LR, and TENS-LL based on the location of the two TENS patches [right (R) or left (L)]. The former and latter letter pairs indicate that the patch locations were the upper chest and upper back, respectively. The heterotypic intermittent stress (HIS) protocol was performed for 16 days. VH was assessed by electromyography to evaluate response to rectal distention (RD). Modulated medium-frequency TENS, sweep range 1-10 Hz, amplitude slightly above the supra motor threshold, was applied 30 min per day followed by RD every second day for the final 7 days of the 16-day HIS period. VH was induced after the rats had been subjected to HIS for 10 days. A significant reduction of VH was observed only in the TENS-LL group compared with that in the sham-control group. These data suggest that repeated TENS treatment can alleviate stress-induced VH in rats. Further, whether TENS patches are attached to the left or right side of the body, which are nonspecific acupoints for gastrointestinal functions, may be an important factor in the treatment of stress-associated gastrointestinal symptoms.

Altered Brain Structure and Functional Connectivity and Its Relation to Pain Perception in Girls With Irritable Bowel Syndrome

OBJECTIVE

Imaging studies in adults with irritable bowel syndrome (IBS) have shown both morphological and resting state (RS) functional connectivity (FC) alterations related to cortical modulation of sensory processing. Because analogous differences have not been adequately investigated in children, this study compared gray matter volume (GMV) and RS-FC between girls with IBS and healthy controls (HC) and tested the correlation between brain metrics and laboratory-based pain thresholds (Pth).

METHODS

Girls with Rome III criteria IBS (n = 32) and matched HCs (n = 26) were recruited. In a subset of patients, Pth were determined using a thermode to the forearm. Structural and RS scans were acquired. A voxel-based general linear model, adjusting for age, was applied to compare differences between groups. Seeds were selected from regions with group GMV differences for a seed-to-voxel whole brain RS-FC analysis. Significance for analyses was considered at p < .05 after controlling for false discovery rate. Significant group differences were correlated with Pth.

RESULTS

Girls with IBS had lower GMV in the thalamus, caudate nucleus, nucleus accumbens, anterior midcingulate (aMCC), and dorsolateral prefrontal cortex. They also exhibited lower RS-FC between the aMCC and the precuneus, but greater connectivity between the caudate nucleus and precentral gyrus. Girls with IBS had higher Pth with a moderate effect size (t(22.81) = 1.63, p = .12, d = 0.64) and lower thalamic GMV bilaterally was correlated with higher Pth (left: r = -.62, p(FDR) = .008; right: r = -.51, p(FDR) = .08).

CONCLUSIONS

Girls with IBS had lower GMV in the PFC, basal ganglia, and aMCC, as well as altered FC between multiple brain networks, suggesting that structural changes related to IBS occur early in brain development. Girls with IBS also showed altered relationships between pain sensitivity and brain structure.

Exogenous serotonin regulates colorectal motility via the 5-HT2 and 5-HT3 receptors in the spinal cord of rats

BACKGROUND

We previously reported that intrathecal injection of noradrenaline or dopamine causes enhancement of colorectal motility. As these monoamines are neurotransmitters of descending pain inhibitory pathways in the spinal cord, we hypothesized that serotonin, which is one of the neurotransmitters involved in descending pain inhibition, also influences the lumbosacral defecation center. Therefore, we examined whether serotonin acting on the spinal defecation center enhances colorectal motility.

METHODS

Colorectal intraluminal pressure and propelled liquid volume were recorded in vivo in anesthetized rats.

KEY RESULTS

Intrathecal injection of serotonin into the L6-S1 spinal cord elicited periodic increases in colorectal intraluminal pressure, being associated with increases in liquid output. Pharmacological experiments revealed that the effect of serotonin is mediated by both 5-HT₂ and 5-HT₃ receptors. The serotonin-induced enhancement of colorectal motility was unaffected even after disconnection of the defecation center from supraspinal regions by cutting the T8 spinal cord, while transection of the parasympathetic pelvic nerves prevented the colokinetic effect of serotonin. Finally, we investigated interactions among serotonin, noradrenaline and dopamine. Simultaneous administration of sub-effective doses of these monoamine neurotransmitters into the spinal cord caused propulsive colorectal motility slightly but substantially.

CONCLUSIONS AND INFERENCES

These results demonstrate that exogenous serotonin acts on 5-HT₂ and 5-HT₃ receptors in the lumbosacral defecation center and activates the parasympathetic nervous system to enhance colorectal motility in cooperation with noradrenaline and dopamine.

High risk of lower urinary tract symptoms in patients with irritable bowel syndrome

BACKGROUND

The aim of the present study was to investigate the prevalence of urinary tract infection (UTI) and the risk of lower urinary tract symptoms (LUTS) in women with irritable bowel syndrome (IBS) (including each subtype: constipation, diarrhea, and mixed) compared to women in the general population.

METHODS

Between January 2014 and December 2015, consecutive adult female patients diagnosed with IBS at the outpatient clinic of the University of Salerno and healthy women with regular bowel habits were enrolled in the study. At baseline, we checked for UTI with a dipstick test and questioned patients about the presence of LUTS in the previous 24 h.

RESULTS

We enrolled 141 IBS patients and 91 healthy controls in the study. There was no difference in the prevalence of UTI between IBS patients and healthy controls (4.9 vs 3.3%, p = 0.5). When we excluded patients with UTI, we found a 2.79 higher risk of increased urinary frequency [odds ratio (OR) 2.79, 95% confidence interval (CI) 1.37-5.68], a 2.68 higher risk of urinary urgency (OR 2.68, 95% CI 1.04-6.91), and more than three times the risk of having dysuria (OR 3.25, 95% CI 1.06-9.97) in IBS women compared to healthy controls. The risk of having at least one urinary symptom was independent of IBS subtype and IBS severity.

CONCLUSIONS

Our study shows that IBS women have a similar risk of UTI compared to healthy women even if they complain more of LUTS, independently of IBS subtype and severity.

Use of rifaximin in gastrointestinal and liver diseases

Rifaximin is a broad spectrum oral antibiotic with antimicrobial activity against Gram-positive and Gram-negative aerobic and anaerobic bacteria. It is poorly absorbed and thus has a highly favorable safety profile. Rifaximin has been shown to be effective in the treatment of traveler’s diarrhea, functional bloating and irritable bowel syndrome, small bowel bacterial overgrowth and in the prevention of recurrent overt hepatic encephalopathy. In addition, there is emerging evidence for a possible beneficial effect of rifaximin in the treatment of uncomplicated diverticular disease and in the prevention of recurrent diverticulitis. The use of rifaximin is associated with a low incidence of development, or persistence of spontaneous bacterial mutants. Moreover, the development of important drug resistance among extra-intestinal flora during rifaximin therapy is unlikely because of minimal systemic absorption and limited cross-resistance of rifaximin with other antimicrobials. This review addresses the current and emerging role of rifaximin in the treatment of gastrointestinal and liver disorders.

The severity of irritable bowel syndrome or the presence of fibromyalgia influencing the perception of visceral and somatic stimuli

BACKGROUND

Fibromyalgia Syndrome (FMS) is a frequent comorbidity in Irritable Bowel Syndrome (IBS) patients with a higher functional bowel disorder severity index (FBDSI). We tested the possibility that mild to severe IBS patients without FMS would have a graduated visceral and somatic perception, and the presence of FMS would further enhance somatic, but conversely attenuate visceral perception.Our aim was to study visceral and somatic sensitivity in mild IBS patients and in severe IBS patients with or without FMS.

METHODS

Eleven mild IBS and 19 severe IBS with and without FMS patients were studied. Somatic and visceral stimuli were applied in each patient by means of electrical stimulations at active and control sites and by means of an electronic barostat in the rectum. Thresholds for discomfort and perception cumulative scores were measured.

RESULTS

Mild and severe IBS patients without FMS demonstrated a significantly lower somatic perception cumulative score than severe IBS patients with FMS at active site. Conversely only severe IBS patients without FMS had significantly lower visceral thresholds for discomfort than mild IBS patients and severe IBS patients with FMS.

CONCLUSIONS

The presence of co-existing FMS or greater FBDSI affects somatic and visceral perception in a graded fashion across IBS patients.

Autonomic response to a visceral stressor is dysregulated in irritable bowel syndrome and correlates with duration of disease

BACKGROUND

Previous studies reported altered autonomic nervous system (ANS) responses in irritable bowel syndrome (IBS) at baseline and to colonic balloon distension. This study examined heart rate variability (HRV) and plasma catecholamines as an index of ANS responsiveness in IBS during flexible sigmoidoscopy (FS) and explored associations of HRV with clinical measures.

METHODS

Rome III-positive IBS patients and healthy controls completed questionnaires measuring gastrointestinal and psychological symptoms. Heart rate variability measures were calculated using electrocardiogram (ECG) data at rest and during FS. Plasma catecholamines were measured before and after the FS. Linear mixed effects models were used to compare HRV with IBS status and IBS duration across six time points. Significance was assessed at the 0.05 level.

KEY RESULTS

Thirty-six IBS patients (53% F, mean age 37.89) and 31 controls (58% F, mean age 37.26) participated. After adjusting for age, sex, body mass index, and current anxiety symptoms, IBS patients had a non-significant lower cardiovagal tone (P = 0.436) and higher cardiosympathetic balance (P = 0.316) at rest. During FS, controls showed a transient increase in cardiosympathetic balance and decrease in cardiovagal tone. However, IBS patients had significantly less cardiosympathetic and cardiovagal responsiveness both leading up to (P = 0.003, P = 0.005) and following (P = 0.001) this stimulus. Those with longer duration of disease had less cardiosympathetic (P = 0.014) and cardiovagal (P = 0.009) responsiveness than those with shorter duration. No differences in catecholamines between IBS and controls were found.

CONCLUSIONS & INFERENCES

Irritable bowel syndrome demonstrated dysregulated ANS responses to a visceral stressor which could be related to disease duration. Therefore, autonomic dysregulation is an objective physiologic correlate of IBS.

Pain/Depression dyad: a key to a better understanding and treatment of functional somatic syndromes

Functional somatic syndromes include some of the most common and frustrating illnesses seen by primary care physicians and medical specialists. An extensive literature search of the 2 best characterized functional somatic syndromes, fibromyalgia and irritable bowel syndrome, reveals the overlap of these 2 disorders and their close relationship to depression. New pathophysiologic studies have shown that there are similar central nervous system changes in fibromyalgia, irritable bowel syndrome, and depression. These clinical and biologic similarities are consistent with the observations that the effective management of fibromyalgia and irritable bowel syndrome is comparable to that of depression.

Widespread hypersensitivity is related to altered pain inhibition processes in irritable bowel syndrome

The mechanisms of chronic pain in irritable bowel syndrome (IBS) have been widely investigated but remain unclear. The present study investigated the relation between visceral hypersensitivity, cutaneous thermal sensitivity, and central pain mechanisms. Rectal sensitivity was assessed with a barostat, and forearm and calf sensitivity with a contact thermode. Central mechanisms were assessed by counterirritation using sustained cold-pain to the hand and painful electric shocks to the ankle. Psychological symptoms were also assessed, using questionnaires. Female volunteers with diarrhea-predominant IBS (n=27) and healthy controls (n=25) participated in the study. IBS patients had lower rectal and calf pain thresholds compared to controls (p's<0.05). IBS patients also reported more pain than controls for rectal distensions, and heat pain on the calf and forearm (all p's<0.001). Cold-pain inhibited shock-pain in controls but not IBS patients (controls: -13.5+/-5.3 vs IBS: +1.9+/-10.5; p<0.01). In addition, visceral hypersensitivity was significantly correlated to cutaneous thermal hypersensitivity and pain inhibition deficits, although effects were only weak and moderate, respectively. Furthermore, covariance analyses indicated that psychological factors accounted for group differences in visceral hypersensitivity and pain inhibition deficits. In conclusion, this study confirms the relation between altered pain inhibition processes and widespread hypersensitivity in IBS. The present results also suggests that psychological symptoms and altered pain processing in IBS patients may reflect at least in part, common underlying mechanisms.

Psychophysiology of visceral pain in IBS and health

The psychophysiology of visceral pain as it relates to gastrointestinal motility, visceral sensitivity, and putative mechanisms of the processing of visceral stimuli by the central and peripheral nervous systems are discussed. Peripheral mechanisms may include low-grade mucosal inflammation, and it is likely that central nervous mechanisms such as neuronal plasticity at the level of the spinal cord and attentional bias at the cortical level are relevant for the chronification of visceral pain. From a psychophysiological perspective, visceral pain therefore remains a complex symptom because behavioral variables, such as the way an individual deals with stress, may be as important for the etiology of visceral pain as, for example, a history of inflammation.

Somatic pain sensitivity in children with recurrent abdominal pain

OBJECTIVE

Evidence is accumulating that recurrent abdominal pain (RAP) in children is associated with visceral hyperalgesia. However, it is not known whether somatic sensitivity is altered as well. Therefore, the aim of our study was to assess somatic pain sensitivity in children with RAP and healthy controls at the abdomen and a distal site (thenar).

METHODS

We examined 20 children with RAP (age 8-14) and 23 healthy control children (age 9-14). Heat and mechanical pain thresholds as well as measures of perceptual sensitization in response to repetitive mechanical or tonic thermal noxious stimulation were assessed.

RESULTS

At the abdominal site, pain sensitivity in children with RAP did not differ significantly when compared to controls. At the thenar, pain thresholds of children in the RAP group were not significantly different from control children. However, children with RAP showed less perceptual sensitization in response to tonic heat and repetitive mechanical stimuli (ps <or= 0.05) than controls.

CONCLUSIONS

We found no evidence for somatic hyperalgesia in RAP arguing against generalized hyperalgesia in these children. Somatic hypoalgesia at the thenar might either be related to a dysregulation of sensory processing and/or attentional avoidance of pain-related stimuli.

Pain perception, blood pressure levels, and peripheral benzodiazepine receptors in patients followed for differentiated thyroid carcinoma: a longitudinal study in hypothyroidism and during hormone treatment

BACKGROUND

Elevated blood pressure levels that are associated with hypalgesia and hypothyroidism have major influences on the cardiovascular system. The potential modulation of pain sensitivity by thyroid hormones is largely undetermined. Moreover, a few experimental studies show that peripheral benzodiazepine receptors (PBRs), which may be altered in hypothyroidism, seem to be related with pain perception.

METHODS

Dental pain threshold and tolerance were evaluated in 19 patients followed for differentiated thyroid carcinoma (1) in severe short-term hypothyroidism (phase 1) and (2) during thyroid stimulating hormone-suppressive LT4 treatment (phase 2). PBR expression (cytofluorimetric evaluation) on peripheral blood mononuclear cells was also investigated in the 2 phases.

RESULTS

Pain perception differed throughout the study, the dental pain threshold was higher in phase 1 (P<0.05) whereas pain tolerance was higher but not significantly (P=0.07). Although the systolic blood pressure was higher during hypothyroidism (P<0.01), no relationship was found between blood pressure changes and pain sensitivity variations. Moreover, the multiple regression analysis showed an independent association of the clinical phase with pain sensitivity (r=-2.61, P=0.029), while accounting for systolic blood pressure. The intensity of PBRs was significantly higher in the first phase of the study (P=0.047) whereas the ratio did not significantly differ. However, no relationship was observed between pain sensitivity and PBRs.

DISCUSSION

In conclusion, in athyreotic patients, the pain sensitivity is related to the thyroid status and is independent of the increase in blood pressure induced by thyroid hormone deprivation. The PBRs do not seem to have major influence on pain sensitivity changes in hypothyroidism.

Functional somatic syndrome: how it could be relevant to rheumatologists

Functional somatic syndrome (FSS) is defined as a group of related syndromes characterized more by symptoms, suffering, and disability than by structural or functional abnormality. The diagnostic criteria and/or symptoms of FSS often overlap, and co-morbidity is commonly found among the diseases of FSS. For example, patients with irritable bowel syndrome often suffer from chronic pain, and a high percentage of co-morbidity can be found with fibromyalgia. Accumulating evidence indicates the presence of visceral and somatic hyperalgesia in FSS as a common feature, and the central sensitization mechanism has been suggested to play an important role in the pathophysiology of FSS. In the present article, the authors introduce the concept of FSS focusing on its possible relevance to rheumatology in terms of pain perception. A possible implication of mast cells and proteinase-activated receptor-2 (PAR-2) in FSS is also reviewed.