Oscillometric pulse wave analysis for detecting low flow arteriovenous fistula

BACKGROUND

Pulse wave analysis may be useful to assess fistula function. We aimed to prospectively evaluate if convenient oscillometric devices are applicable to detect flow below 500 ml/min in a real life clinical setting.

METHODS

Pulse waves were recorded ambilaterally with the vicorder® device at the brachial artery in 53 patients on haemodialysis with native fistula. Primary variables consisted of the mean slope between the systolic maximum and the diacrotic notch (Slope2), the sum of the mean slopes in the four characteristic sections of pulse waves (Slope∑) and the amplitude of relative volumetric change in the measuring cuff at the upper arm (AMP). Fistula flow was measured with the use of duplex sonography using a standardized approach.

RESULTS

Parameter values above or below the median indicated measurement at the non-fistula side, with sensitivities/specificities of 0.79/0.79 (p < 0.001) for Slope 2, 0.64/0.64 (p = 0.003) for Slope∑ and 0.81/0.81 (p < 0.001) for AMP if measurements at the fistula and non-fistula arm were considered. ROC-analyses of parameter values measured at the fistula to detect low flow demonstrated AUCs (with CI) of 0.652 (0.437-0.866, p = 0.167) for Slope2, 0.732 (0.566-0.899, p = 0.006) for Slope∑ and 0.775 (0.56-0.991, p = 0.012) for AMP. The point with maximal youden's index was regarded as optimal cut-off, which corresponded to sensitivities and specificities of 0.8/0.56 for slope2, 0.86/ 0.56 for Slope∑ and 0.93/0.78 for AMP.

CONCLUSION

Functional surveillance with oscillometry is a promising clinical application to detect a low fistula flow. Among all investigated pulse wave parameters AMP revealed the highest diagnostic accuracy.

Polyclonal Immunotactoid Glomerulopathy Associated with Monoclonal Gammopathy of IgM Type and Underlying Plasmacellular Disease: Successful Treatment with Rituximab Alone

Immunotactoid glomerulopathy (ITG) occurs infrequently and is characterized by organized IgG containing deposits. It most usually manifests as a concomitant disease of a broad spectrum of oncologic entities. We here present an exceptional case of ITG without glomerular light chain restriction secondary to a IgM kappa type monoclonal gammopathy of undetermined significance. Due to nephrotic syndrome and deterioration of kidney function a rituximab monotherapy was initiated without targeting the plasmacellular augmentation, which was confirmed as the underlying process. The treatment led to a long-term improvement of proteinuria and stabilization of glomerular filtration rate. Its therapeutic effect has to be attributed to immunomodulatory capacities and targeting of podocytes rather than to be interpreted as directed against a bone marrow or glomerular clone. We conclude that rituximab therapy may be a valuable part of the therapeutic options in ITG irrespective of the underlying oncologic entity.

MO164NOVEL PARAMETERS TO ASSESS ENDOTHELIAL DYSFUNCTION BY PULSE WAVE ANALYSIS

Background and Aims

Pulse wave morphology changes under the high flow condition of reactive hyperaemia. We hypothesized, that those alterations may be able to indicate endothelial dysfunction.

Method

We recorded digitized pulse waves measured tonometrically with the SphygmoCor® device of 64 persons, 41 kidney transplant recipients and 23 healthy individuals, under normal conditions (NC) and under reactive hyperaemia (RH). Using matlab®, we calculated novel parameters, which had a temporal relationship with 3 charactereristic points (PO) of the normalized pulse wave, namely the maximum of the antegrade wave (1), the diacrotic notch (2) and the first diastolic inflection point (3). The following parameters were calculated: Mean slope between PO 1 and 2 (λ2), area under the curve (AUC) in the systole (Asys), AUC between PO 1 and 3 (A13), AUC between PO 1 and 2 (A12) and AUC between PO 2 and 3 (A23). Parameters were analyzed as their difference under reactive hyperaemia and under normal conditions. Also the maximum of the instantaneous difference of normalized pulse waves under NC und RH (Dmax) was analyzed. Endothelial function was evaluated by duplex sonography using ROC-analysis of peak systolic and end-diastolic flow difference under NC and RH.

Results

ROC-assessment of endothelial dysfunction as indicated by systolic peak flows demonstrated AUCs of 0.733 for λ2 (p=0.002), 0.751 for Dmax (p&lt; 0.001), 0.698 for Asys (p=0.006), 0.648 for A13 (p=0.077), 0.678 for A12 (p=0.027) and 0.732 for A23 (p=0.001). For the diastole the values were 0.753 for λ2 (p=0.003), 0.733 for Dmax (p=0.002) 0.670 for Asys (p=0.038), 0.566 for A13 (p=0.495), 0.664 for A12 (p=0.091) and 0.722 for A23 (p=0.015) respectively.

Conclusion

Pulse wave analysis under the condition of reactive hyperaemia probably is useful to assess endothelial function in kidney transplant recipients.

The Amsterdam Healthy Weight Approach: A whole systems approach for tackling child obesity in cities

In search for successful overweight and obesity prevention, extensive research has shown that programs focused on individual behavior change are not effective enough. Many of the underlying determinants of overweight and obesity have social, environmental and economic origins, and extend even beyond the influence of the health sector and public health. This calls for a whole systems approach that covers a multi-sectoral, multi-stakeholder collaboration, where communities, professionals, government and industry are involved and are all part of the solution.

The Amsterdam Healthy Weight Approach (AHWA), initiated in 2012, is a local government led approach that has the objective to encourage healthy weight for children in a healthy environment. With a long-term vision, aimed at lasting change, the AHWA aims at developing interventions, changing policies and educating and informing both professionals and target groups within the communities that are most heavily burdened with the issue of child obesity (and related complex health/wellbeing issues). The strength of the AHWA lies in adopting a whole systems approach (WSA), in which the key is, to collaborate in an integrated, multi-level, multi sectoral way, with a variety of stakeholders from within and outside the field of public health.

The aim of the presentation is to inform participants from cities around the globe about the success factors, lessons learned and valuable elements of implementing the AHWA, and to provide tools which they can use in discussing their own approaches and bring these to a higher level of effectiveness

Pulse Wave Analysis and Pulse Wave Velocity for Fistula Assessment

BACKGROUND/AIMS

Pulse wave analysis (PWA) and pulse wave velocity (PWV) provide information about arterial stiffness and elasticity, which is mainly used for cardiovascular risk stratification. In the presented prospective observational pilot study, we examined the hypothesis that radiocephalic fistula (RCF)-related changes of haemodynamics and blood vessel morphology including high as well as low flow can be seen in specific changes of pulse wave (PW) morphology.

METHODS

Fifty-six patients with RCF underwent local ambilateral peripheral PWA and PWV measurement with the SphygmoCor® device. Given that the output parameters of the SphygmoCor® are not relevant for the study objectives, we defined new suitable parameters for PWA in direct proximity to fistulas and established an appropriate analysing algorithm. Duplex sonography served as reference method.

RESULTS

Marked changes of peripheral PW morphology when considering interarm differences of slope and areas between the fistula and non-fistula arms were observed in the Arteria radialis, A. brachialis and arterialized Vena cephalica. The sum of the slope differences was found to correlate with an increased flow, while in patients with fistula failure no changes in PW morphology were seen. Moreover, PWV was significantly reduced in the fistula arm.

CONCLUSION

Beside duplex sonography, ambilateral peripheral PWA and PWV measurements are potential new clinical applications to characterize and monitor RCF function, especially in terms of high and low flow.

P1333PULSE WAVE ANALYSIS UNDER THE CONDITIONS OF HIGH ARTERIAL FLOW: ASSESSMENT OF SHUNT FUNCTION AND REACTIVE HYPEREMIA

Background and Aims

Fistula-creation as well as reactive hyperaemia increase local arterial blood flow. We wanted to analyse the impact of these haemodynamic changes on pulse wave (PW) morphology to assess fistula- and endothelial function.

Method

We conducted a clinical pilot study including 56 patients with functioning forearm fistula. PW morphology in the A. brachialis was assessed tonometrically at the non-fistula and fistula arm using the SpygmoCor® device. We also performed a PW analysis on the non-fistula arm under the condition of reactive hyperaemia (possible in 43 patients). Duplex-sonography was used as a complementary and reference method.

Results

In comparison to measurements under physiologic conditions, both the fistula arm (a) and the non-fistula arm with reactive hyperemia (b) showed marked differences in the pulse wave morphology (figure). The changes in PW morphology were most prominent in the area of the diacrotic notch and could be assessed as the differences of the sum of the mean slope (Δλ in mmHg/ms) between the diacrotic notch and the main preceding and subsequent inflexion point. Measurement with duplex-sonography confirmed increased peak blood flow velocity in the arteria brachialis (ΔVmax in cm/s) under both conditions.

Statistical significance could be proved for Δλ and for ΔVmax (table). Finally, bivariate regression analysis revealed a correlation of Δλ with ΔVmax (figure; c: p=0.001 and r=-0,483 for interarm-differences of the fistula and non-fistula arm; d: p= 0.030 and r=-0.343 for the differences between the physiologic state and reactive hyperaemia at the non-fistula arm).

Conclusion

PW analysis under high flow conditions has the potential to be a new useful clinical tool in nephrology to monitor fistula- as well as endothelial function assessed by reactive hyperaemia. The findings should be verified in a trial with clinical endpoints.

Occipital Nerve Blockade in Chronic Cluster Headache Patients and Functional Connectivity Between Trigeminal and Occipital Nerves

Headache syndromes often involve occipital and neck symptoms, suggesting a functional connectivity between nociceptive trigeminal and cervical afferents. Although reports regarding effective occipital nerve blockades in cluster headache exist, the reason for the improvement of the clinical symptoms is not known. Using occipital nerve blockade and nociceptive blink reflexes, we were able to demonstrate functional connectivity between trigeminal and occipital nerves in healthy volunteers. The R2 components of the nociceptive blink reflex and the clinical outcome in 15 chronic cluster headache patients were examined before and after unilateral nerve blockade of the greater occipital nerve with 5 ml prilocain (1%) on the headache side. In contrast to recent placebo-controlled studies, only nine of the 15 cluster patients reported some minor improvement in their headache. Six patients did not report any clinical change. Exclusively on the injection side, the R2 response areas decreased and R2 latencies increased significantly after the nerve blockade. These neurophysiological and clinical data provide further evidence for functional connectivity between cervical and trigeminal nerves in humans. The trigeminocervical complex does not seem to be primarily facilitated in cluster headache, suggesting a more centrally located pathology of the disease. However, the significant changes of trigeminal function as a consequence of inhibition of the greater occipital nerve were not mirrored by a significant clinical effect, suggesting that the clinical improvement of occipital nerve blockades is not due to a direct inhibitory effect on trigeminal transmission.

Antigen-Specific versus Non-Antigen-Specific Immunoadsorption in ABO-Incompatible Renal Transplantation

Introduction

ABO-incompatible (ABOi) renal transplantation (RTx) from living donors is an established procedure to expand the donor pool for patients with end stage renal disease. Immunoadsorption (IA) is a standard procedure for the removal of preformed antibodies against the allograft. In this study, antigen-specific and non-antigen-specific IA in ABOi RTx were compared.

Patients and Methods

10 patients underwent antigen-specific IA (Glycosorb group) and 13 patients non-antigen-specific IA (Immunosorba group). The effects of both procedures regarding antibody reduction, number of treatments, complications, costs, as well as the allograft function and patient survival were compared between both groups.

Results

Although the IgG levels were reduced equally by both procedures (p=0.82), the reduction of the IgM level was more effective in the Glycosorb group (p=0.0172). Patients in both groups required a median number of 6 IA before ABOi RTx. Allograft function at one year after AB0i RTx was similar in both groups (estimated glomerular filtration rate: 66 vs. 64 ml/min/1.73m² respectively), with a death-censored graft survival of 90.0% and 92.3% respectively. Complication rates did not differ between procedures. Due to the reuse of non-antigen-specific Immunosorba columns, costs were considerably lower in this group; however, the use of the Immunosorba-based IA was less time-efficient.

Conclusion

Considering upcoming alternatives as simultaneous performance of dialysis and IA or a possible reuse of Glycosorb columns, this might become less relevant in the future.

Best supportive care and therapeutic plasma exchange with or without eculizumab in Shiga-toxin-producing E. coli O104:H4 induced haemolytic-uraemic syndrome: an analysis of the German STEC-HUS registry

BACKGROUND

May 22nd marks the beginning of a Shiga-toxin-producing Escherichia coli (STEC) O104:H4 outbreak in Northern Germany. By its end on 27 July, it had claimed 53 deaths among 2987 STEC and 855 confirmed haemolytic-uraemic syndrome (HUS) cases.

METHODS

To describe short-term effectiveness of best supportive care (BSC), therapeutic plasma exchange (TPE) and TPE with eculizumab (TPE-Ecu) in 631 patients with suspected HUS treated in 84 hospitals in Germany, Sweden and the Netherlands using the web-based registry of the DGfN (online since 27 May).

RESULTS

Of 631 entries, 491 fulfilled the definition of HUS (median age 46 years; 71% females). The median (inter-quartile range) hospital stay was 22 (14-31) days. Two hundred and eighty-one (57%) patients underwent dialysis and 114 (23%) mechanical ventilation. Fifty-seven patients received BSC, 241 TPE and 193 TPE-Ecu. Treatment strategy was dependent on disease severity (laboratory signs of haemolysis, thrombocytopenia, peak creatinine level, need for dialysis, neurological symptoms, frequency of seizures) which was lower in BSC than in TPE and TPE-Ecu patients. At study endpoint (hospital discharge or death), the median creatinine was lower in BSC [1.1 mg/dL (0.9-1.3)] than in TPE [1.2 mg/dL (1.0-1.5), P < 0.05] and TPE-Ecu [1.4 mg/dL (1.0-2.2), P < 0.001], while need for dialysis was not different between BSC (0.0%, n = 0), TPE (3.7%; n = 9) and TPE-Ecu (4.7%, n = 9). Seizures were absent in BSC and rare in TPE (0.4%; n = 1) and TPE-Ecu (2.6%; n = 5) patients. Total hospital mortality in HUS patients was 4.1% (n = 20) and did not differ significantly between the TPE and TPE-Ecu groups.

CONCLUSIONS

Despite frequent renal impairment, advanced neurological disorders and severe respiratory failure, short-term outcome was better than expected when compared with previous reports. Within the limitations of a retrospective registry analysis, our data do not support the notion of a short-term benefit of Ecu in comparison to TPE alone in the treatment of STEC-HUS. A randomized trial comparing BSC, TPE and Ecu seems to be prudent and necessary prior to establishing new treatment guidelines for STEC-HUS.

Alexithymic and somatisation scores in patients with temporomandibular pain disorder correlate with deficits in facial emotion recognition

Current studies suggest dysfunctional emotional processing as a key factor in the aetiology of temporomandibular disorder (TMD). Investigating facial emotion recognition (FER) may offer an elegant and reliable way to study emotional processing in patients with TMD. Twenty patients with TMD and the same number of age-, sex- and education-matched controls were measured with the Facially Expressed Emotion Labelling (FEEL) test, the 26-item Toronto Alexithymia Scale (TAS-26), the Screening for Somatoform Symptoms (SOMS-2a), the German Pain Questionnaire and the 21-item Hamilton Depression Rating Scale (HAMD). The patients had significantly lower Total FEEL Scores (P = 0·021) as compared to the controls, indicating a lower accuracy of FER. Furthermore, we were able to demonstrate significant group differences with respect to the following issues: patients were more alexithymic (P = 0·006), stated more somatoform symptoms (P < 0·004) and had higher depressive scores in the HAMD (P < 0·003). The factors alexithymia and somatisation could explain 31% (adjusted 27%) of the variance of the FEEL Scores in the sample. The estimation of the standardised regression coefficients suggests an equivalent influence of TAS-26 and SOMS-2a on the FEEL Scores, whereas 'group' (patients versus healthy controls) and depressive symptoms did not contribute significantly to the model. Our findings highlight FER deficits in patients with TMD, which are partially explained by concomitant alexithymia and somatisation. As suggested previously, impaired FER in patients with TMD may further point to probable aetiological proximities between TMD and somatoform disorders.

Best supportive care and therapeutic plasma exchange with or without eculizumab in Shiga-toxin-producing E. coli O104:H4 induced haemolytic-uraemic syndrome: an analysis of the German STEC-HUS registry

BACKGROUND

May 22nd marks the beginning of a Shiga-toxin-producing Escherichia coli (STEC) O104:H4 outbreak in Northern Germany. By its end on 27 July, it had claimed 53 deaths among 2987 STEC and 855 confirmed haemolytic-uraemic syndrome (HUS) cases.

METHODS

To describe short-term effectiveness of best supportive care (BSC), therapeutic plasma exchange (TPE) and TPE with eculizumab (TPE-Ecu) in 631 patients with suspected HUS treated in 84 hospitals in Germany, Sweden and the Netherlands using the web-based registry of the DGfN (online since 27 May).

RESULTS

Of 631 entries, 491 fulfilled the definition of HUS (median age 46 years; 71% females). The median (inter-quartile range) hospital stay was 22 (14-31) days. Two hundred and eighty-one (57%) patients underwent dialysis and 114 (23%) mechanical ventilation. Fifty-seven patients received BSC, 241 TPE and 193 TPE-Ecu. Treatment strategy was dependent on disease severity (laboratory signs of haemolysis, thrombocytopenia, peak creatinine level, need for dialysis, neurological symptoms, frequency of seizures) which was lower in BSC than in TPE and TPE-Ecu patients. At study endpoint (hospital discharge or death), the median creatinine was lower in BSC [1.1 mg/dL (0.9-1.3)] than in TPE [1.2 mg/dL (1.0-1.5), P < 0.05] and TPE-Ecu [1.4 mg/dL (1.0-2.2), P < 0.001], while need for dialysis was not different between BSC (0.0%, n = 0), TPE (3.7%; n = 9) and TPE-Ecu (4.7%, n = 9). Seizures were absent in BSC and rare in TPE (0.4%; n = 1) and TPE-Ecu (2.6%; n = 5) patients. Total hospital mortality in HUS patients was 4.1% (n = 20) and did not differ significantly between the TPE and TPE-Ecu groups.

CONCLUSIONS

Despite frequent renal impairment, advanced neurological disorders and severe respiratory failure, short-term outcome was better than expected when compared with previous reports. Within the limitations of a retrospective registry analysis, our data do not support the notion of a short-term benefit of Ecu in comparison to TPE alone in the treatment of STEC-HUS. A randomized trial comparing BSC, TPE and Ecu seems to be prudent and necessary prior to establishing new treatment guidelines for STEC-HUS.

Validation of treatment strategies for enterohaemorrhagic Escherichia coli O104:H4 induced haemolytic uraemic syndrome: case-control study

OBJECTIVE

To evaluate the effect of different treatment strategies on enterohaemorrhagic Escherichia coli O104:H4 induced haemolytic uraemic syndrome.

DESIGN

Multicentre retrospective case-control study.

SETTING

23 hospitals in northern Germany.

PARTICIPANTS

298 adults with enterohaemorrhagic E coli induced haemolytic uraemic syndrome.

MAIN OUTCOME MEASURES

Dialysis, seizures, mechanical ventilation, abdominal surgery owing to perforation of the bowel or bowel necrosis, and death.

RESULTS

160 of the 298 patients (54%) temporarily required dialysis, with only three needing treatment long term. 37 patients (12%) had seizures, 54 (18%) required mechanical ventilation, and 12 (4%) died. No clear benefit was found from use of plasmapheresis or plasmapheresis with glucocorticoids. 67 of the patients were treated with eculizumab, a monoclonal antibody directed against the complement cascade. No short term benefit was detected that could be attributed to this treatment. 52 patients in one centre that used a strategy of aggressive treatment with combined antibiotics had fewer seizures (2% v 15%, P = 0.03), fewer deaths (0% v 5%, p = 0.029), required no abdominal surgery, and excreted E coli for a shorter duration.

CONCLUSIONS

Enterohaemorrhagic E coli induced haemolytic uraemic syndrome is a severe self limiting acute condition. Our findings question the benefit of eculizumab and of plasmapheresis with or without glucocorticoids. Patients with established haemolytic uraemic syndrome seemed to benefit from antibiotic treatment and this should be investigated in a controlled trial.

Effects of acupuncture needle penetration on motor system excitability

OBJECTIVES

Transcranial magnetic stimulation (TMS) studies reported changes in motor evoked potential amplitude after acupuncture needling both at traditional acupoints and non-acupoints. However, the effects of needle penetration per se have not yet been investigated with TMS. The present study aimed at exploring effects of deep manual acupuncture needling compared to a state-of-the-art, non-penetrating control condition on several standard TMS measures of motor system excitability.

METHODS

Twenty healthy volunteers received both verum and sham acupuncture applied at the acupoint GB 34 near the right knee, using a crossover design. A needle with a retractable tip ("Streitberger needle") was used as sham condition to minimize non-specific effects. TMS parameters (resting motor threshold, active motor threshold, cortical silent period, short intracortical inhibition, and intracortical facilitation) were calculated from the abductor digiti minimi (ADM) of both hands 15 min before and after needling by a researcher blind to the treatment condition.

RESULTS

Verum compared to sham acupuncture significantly increased resting motor threshold. No significant treatment effect was found for any other measure, though cortical silent period and intracortical facilitation showed trends to increase in the hemisphere contralateral to the needling site after verum acupuncture.

CONCLUSIONS

These results suggest a subtle but specific inhibitory effect of acupuncture needle penetration at acupoint GB 34 on motor system excitability. Further investigations should be performed with a particular emphasis on the measurements of resting motor threshold, cortical silent periods and intracortical facilitation.

[Impact of physiotherapy, massages and lymphatic drainage in migraine therapy]

Physical treatment, spinal manipulative therapy and massages are often recommended to treat migraine as a prophylactic therapy. Clinical experience and theoretical concepts support their usefulness. However, data on these therapies are scarce. On the basis of the available studies, it is impossible to determine whether or not these therapies are effective. There is a lack of well-designed prospective, randomized controlled trials with a sufficiently long follow-up to observe these therapies. Due to the high acceptance of physical treatment on the one hand and preconceptions about drug treatment on the other, these types of therapies may be an alternative option for some patients if their efficacy is established. A cost-benefit analysis of theses therapies should consider the long amount of time required for them compared with drug intake.

Low-Frequency Short-Time Nociceptive Stimulation of the Greater Occipital Nerve does not Modulate the Trigeminal System

Occipital stimulation in a small group of refractory chronic migraine and cluster headache patients has been suggested as a novel therapeutic approach with promising results. In an earlier study we have shown that a drug-induced block of the greater occipital nerve (GON) inhibits the nociceptive blink reflex (nBR). Now, we sought to examine the effects of low-frequency (3 Hz) short-time nociceptive stimulation of the GON on the trigeminal system. We recorded the nBR responses before and after stimulation in 34 healthy subjects. Selectivity of GON stimulation was confirmed by eliciting somatosensory evoked potentials of the GON upon stimulation. In contrast to an anaesthetic block of the occipital nerve, no significant changes of the R2-latencies and R2-response areas of the nBR can be elicited following GON stimulation. Various modes of electrical stimulation exist with differences in frequency, stimulus intensity, duration of stimulation and pulse width. One explanation for a missing modulatory effect in our study is the relatively short duration of the stimulation.

[Exercise in migraine treatment. Review and discussion of clinical trials and implications for further trials]

Regular exercise is recommended in general treatment guidelines for migraine. However, scientific evidence in support of this recommendation is weak. The majority of available trials on this topic do not meet modern requirements for randomized clinical trials. Often the diagnosis of migraine is not certain, the duration of treatment is too short, and the intervention is not clearly defined; furthermore, the control of treatment is insufficient. The study results are controversial regarding the efficiency of sports intervention in migraine. Regular exercises may have specific effects on the course of disease in migraine through increase of fitness or relaxing effects. It remains unclear whether exercise alone is efficient in migraine treatment or only as part of a more multidisciplinary program. Theoretical considerations, the available limited studies, and clinical experience suggest that exercise may have an effect on migraine, but the present knowledge does not fulfill the needs of evidence-based medicine. Future studies should adhere to the rules for randomized clinical trials in pharmacological migraine prophylaxis.

Sumatriptan and corneal reflexes in headache-free migraine patients: a randomized and placebo-controlled crossover study

A temporary sensitization of central trigeminal neurones in migraine patients during acute attacks has been described in previous studies using the electrically evoked nociceptive blink reflex. The cornea is innervated by small myelinated A-delta and unmyelinated C-fibres only. Stimulation with air puffs activates peripheral nociceptors and allows the investigation of peripheral trigeminal nerve structures. Our objective was to investigate whether corneal reflex examinations with air puff stimulation detect abnormalities in migraineurs during their pain-free interval and if the corneal reflex may be modulated by the administration of an oral triptan. After validation of the nociceptive air puff technique by investigating the corneal reflexes before and after a local anaesthesia of the cornea, we recorded corneal reflexes in 25 migraineurs during their pain-free period and 25 healthy controls before and after the oral administration of 100 mg sumatriptan in a randomized, placebo-controlled, crossover study. Baseline response areas under the curve (AUCs) and latencies of the R2 components of the corneal reflexes did not show any significant differences between patients and controls. Patients did not show any significant differences regarding their headache and non-headache side. The use of an oral triptan had no significant influence on latencies or AUCs in both patients and controls. Our data suggest that there is no facilitation of the trigeminal system in the headache-free interval among patients with migraine. The stable corneal reflexes after the oral administration of 100 mg sumatriptan suggest that there was no inhibition of the trigeminal system, both in patients during their headache-free period and in healthy controls.

Functional connectivity between trigeminal and occipital nerves revealed by occipital nerve blockade and nociceptive blink reflexes

Headache syndromes often suggest occipital and neck involvement, although it is still unknown to what extent branches of segment C1-C3 contribute actively to primary headache. Pain within the occipital area may be referred to the trigeminal territory. However, a modulation of trigeminal transmission by affecting cervical input in humans has not been elucidated so far. A convergence of cervical and trigeminal input at the level of the caudal part of the trigeminal nucleus in the brainstem has been suggested due to anatomical and neurophysiological studies in animals. We examined the R2 components of the nociceptive blink reflex responses in 15 healthy subjects before and after unilateral nerve blockade of the greater occipital nerve with 5 ml prilocain (1%). R2 response areas (AUC) decreased and the R2 latencies increased significantly after the nerve blockade only on the side of injection. AUC and latencies on the non-injection side remained stable. Thresholds for sensory or pain perception did not differ significantly between the repeated measurements on both sides. Our findings extend previous results related to anatomical and functional convergence of trigeminal and cervical afferent pathways in animals and suggest that the modulation of this pathway is of potential benefit in primary headache disorders.

Subcutaneous microdialysis for children - safe biochemical tissue monitoring based on a minimal traumatizing no touch insertion technique

BACKGROUND

Microdialysis (MD) enables analysis of extracellular metabolites without performing blood tests. Changes in the concentration of various metabolites can be monitored frequently on almost every type of human tissue. Microdialysis of subcutaneous tissue (sc MD) is of particular significance in the case of pediatric patients because diurnal profiles can be generated without repeated blood sampling. There are only a few scientific articles that describe the application of sc MD on neonates, infants, or children. So far, side effects have not been investigated comprehensively. This prospective study scrutinizes side effects of sc MD in pediatric patients, focusing on a Minimal Traumatizing Insertion Technique of the MD catheter.

PATIENTS AND METHODS

42 pediatric patients within four age categories participated in the study which involved bedside monitoring using sc MD, including 5 extremely low birth weight (ELBW) infants with a body weight <1000g. A total of 48 sc MD catheters were inserted. Selection criteria were risk of hypoglycaemia (n = 29), elevated lactate levels (n = 16), or aminoacidopathies (n = 3). Duration of sc MD ranged from 1 to 16 days. We used a Minimal Traumatizing Insertion Technique to safely insert the MD catheter into the subcutaneous tissue, characterized by blunt dissection of the tissue and by the use of a plastic cannula guidance to avoid desterilisation of the catheter. Complications and side effects related to sc MD were documented in standardized forms.

RESULTS

The MD probe was easily placed even in the scanty adipose tissue of ELBW infants. During insertion of sc MD catheters accidental venous puncture occurred to 8%, and minor bleeding to 27%. Even with local anaesthesia insertion was painful for 40%. During the course of sc MD complications were rare: disturbance of perfusion flow 4%, catheter dislocation 4%, local bleeding 4%. No signs of systemic or local infection were observed, there were no cases of local incompatibility. All catheters were withdrawn completely without leaving a scar. Repeated measurements allowed the generation of diurnal metabolic profiles. In some cases (respiratory chain complex I deficiency, PDH-deficiency) significant therapeutical effects on the patients' metabolism were demonstrated.

CONCLUSIONS

The present study proves long-term sc MD to be suitable and safe for biochemical tissue monitoring. Using our insertion technique, it can be applied to children of all ages without causing discomfort or severe side effects. As it permits frequent sampling it allows evaluating and optimizing therapy and means a substantial progress for pediatric observation.

Der trigeminozervikale Komplex

The activation of the trigeminal nociceptive system is the neural substrate of pain in primary headache syndromes such as migraine and cluster headache. The nociceptive inflow from the meninges to the spinal cord is relayed in brainstem neurones of the trigemino-cervical complex (TCC). Two important mechanisms of pain transmission are reviewed: convergence of nociceptive trigeminal and cervical afferents and sensitization of trigemino-cervical neurones. These mechanisms have clinical correlates such as hyperalgesia, allodynia, spread and referral of pain to trigeminal or cervical dermatomes. Neurones in the TCC are subject to a modulation of pain-modulatory circuits in the brainstem such as the periaqueductal grey (PAG). Recent experimental and clinical findings of a modulation of these pain processes are discussed. The review focuses on TCC neurones as integrative relay neurones between peripheral and central pain mechanisms. The understanding of these mechanisms has implications for the understanding of the clinical phenomenology in primary headache syndromes and the development of therapeutical options.

[Trigemino-autonomic headache syndromes]

This review describes the characteristics of some rare severe primary headache syndromes without any structural lesions, which are summarized as the trigemino-autonomic headaches. Pain in these syndromes is associated with autonomic symptoms such as conjunctival injection, lacrimation, rhinorrhoe, ptosis or eyelid edema. This article summarizes the diagnostics, epidemiology and therapy of these conditions.