The skeletal muscle phenotype of children with Neurofibromatosis Type 1 - A clinical perspective

Neurofibromatosis type 1 (NF1) can affect multiple systems in the body. An under recognised phenotype is one of muscle weakness. Clinical studies using dynamometry and jumping mechanography have demonstrated that children with NF1 are more likely to have reduced muscle force and power. Many children with NF1 are unable to undertake physical activities to the same level as their peers, and report leg pains on physical activity and aching hands on writing. Children and adolescents with NF1 reporting symptoms of muscle weakness should have a focused assessment to exclude alternative causes of muscle weakness. Assessments of muscle strength and fine motor skills by physiotherapists and occupational therapists can provide objective evidence of muscle function and deficits, allowing supporting systems in education and at home to be implemented. In the absence of an evidence base for management of NF1-related muscle weakness, we recommend muscle-strengthening exercises and generic strategies for pain and fatigue management. Currently, trials are underway involving whole-body vibration therapy and carnitine supplementation as potential future management options.

The Human Posterior Superior Temporal Sulcus Samples Visual Space Differently From Other Face-Selective Regions

Neuroimaging studies show that ventral face-selective regions, including the fusiform face area (FFA) and occipital face area (OFA), preferentially respond to faces presented in the contralateral visual field (VF). In the current study we measured the VF response of the face-selective posterior superior temporal sulcus (pSTS). Across 3 functional magnetic resonance imaging experiments, participants viewed face videos presented in different parts of the VF. Consistent with prior results, we observed a contralateral VF bias in bilateral FFA, right OFA (rOFA), and bilateral human motion-selective area MT+. Intriguingly, this contralateral VF bias was absent in the bilateral pSTS. We then delivered transcranial magnetic stimulation (TMS) over right pSTS (rpSTS) and rOFA, while participants matched facial expressions in both hemifields. TMS delivered over the rpSTS disrupted performance in both hemifields, but TMS delivered over the rOFA disrupted performance in the contralateral hemifield only. These converging results demonstrate that the contralateral bias for faces observed in ventral face-selective areas is absent in the pSTS. This difference in VF response is consistent with face processing models proposing 2 functionally distinct pathways. It further suggests that these models should account for differences in interhemispheric connections between the face-selective areas across these 2 pathways.

Learning from calorie posting/traffic light systems introduction in a University hospital canteen

Key messages

Introduction of traffic light system and calorie posting needs evaluation. Females appear more likely to avail of traffic light systems and calorie posting in relation to food choices.

Ogilvie's syndrome: a case report

OBJECTIVE

Ogilvies syndrome (OS) is a rare condition in obstetrics but occurs most commonly after caesarean section. Mortality rates from OS can be as high as 36-50% when bowel perforation or ischemia develops which highlights the early recognition of this condition. Early diagnosis is therefore essential to prevent serious morbidity and mortality.

CONCLUSION

We, therefore report a case of OS after caesarean section in which early detection by senior clinicians resulted in successful management of the condition and an excellent outcome.

Clinical validation of methods of diagnosis of neuropathy in a field study of United Kingdom sheep dippers

OBJECTIVES

To investigate the reproducibility of measured indices of chronic peripheral neuropathy from a field study of sheep dippers when compared with similar measurements carried out in a clinical setting.

METHODS

A stratified random sample of field study subjects was invited to attend a clinic. Neuropathy was measured both in the field and at the clinic with a modified version of a standard symptoms questionnaire and quantitative sensory thresholds for hot, cold, and vibration. These were combined into a classification of the likelihood of neuropathy with a neuropathy scoring system. Indicators of sensory abnormality were based on comparison of sensory thresholds to age dependent reference values derived from an external reference group.

RESULTS

Only 51% of subjects were assigned similar classifications in the field and clinic based on the neuropathy scoring system. Of the component indices, grouped symptom scores, with 65% of subjects showing exact agreement, proved to be more reproducible than quantitative sensory test indicators. There were biases in the comparison of field and clinic measurements of hot and vibration sensations, but no evidence of greater variation between individual people in sensory thresholds in the field relative to at the clinic.

CONCLUSIONS

The neuropathy scoring system proved to be of limited reproducibility, due in a large part to the lack of reproducibility of the indicators of sensory test abnormality caused by inadequate temperature control. However, the symptoms score and measured sensory thresholds could be used separately as indices of neuropathy in exposure-response analyses.

A clinical neurological, neurophysiological, and neuropsychological study of sheep farmers and dippers exposed to organophosphate pesticides

OBJECTIVES

To classify clinical diseases of the subjects with abnormal indices of peripheral neuropathy identified in field studies of sheep farmers and dippers exposed to organophosphate pesticides. To explore what neuropsychological profiles, if any, may be associated with neurophysiological damage in these subjects.

METHODS

A case-control study (79 subjects) nested within the cross sectional study (685 subjects) of sheep farmers from the field study. Three groups with no, possible, and probable or definite neuropathy according to field studies were recruited. Investigations comprised symptoms of neuropathy, neurologial signs, motor and sensory nerve conduction, electromyography, quantitative sensory testing, and neuropsychological tests.

RESULTS

The incidence of clinical neuropathy increased from 7% in the no neuropathy group to 52% in the probable or definite neuropathy group based on nerve conduction measurements or presence of neurological signs. Sensory abnormalities were found more often than motor deficits. Small diameter nerve fibres were also affected more than large fibres.

CONCLUSIONS

The neuropathy is predominantly sensory and is characteristic of distal, chronic neuropathy with no acute features. Small fibre populations are affected more than large fibre populations. Increasing severity of neuropathy was associated with anxiety and depression as measured in the neuropsychological tests.

Estimation of cumulative exposure to organophosphate sheep dips in a study of chronic neurological health effects among United Kingdom sheep dippers

OBJECTIVES

To derive a method for retrospectively estimating cumulative exposure to organophosphate (OP) pesticides among a cross section of United Kingdom sheep dippers, as part of a wider epidemiological study of neurological abnormality within this group of workers.

METHODS

A hygiene study of dipping sessions at 20 farms using diazinon based dips was carried out by two experienced occupational hygienists. Observations on the exposure of people to concentrate and dilute dip were recorded throughout each dipping session, together with the other relevant factors including the use and condition of protective clothing. Concentrations of urinary metabolites of diazinon were used to measure actual exposure to OPs. To estimate exposure in the subsequent epidemiological study, an occupational exposure history questionnaire was developed using results from the hygiene study and an empirical exposure model.

RESULTS

In the hygiene study, increased urinary metabolites were associated with the handling of concentrate dip and exposure to dilute dip wash through splashing. Very few dippers wore the recommended protective clothing. The handling of concentrate dip was the principal source of exposure to OPs. Dipping task was used as a surrogate for splashing of dilute dip in retrospective exposure estimation. In the epidemiological study, cumulative exposure to OP sheep dips was highly correlated with the total number of dipping days, but not with age.

CONCLUSIONS

Sheep dip concentrate is the most important source of OP exposure among sheep dippers and estimates of exposure to OPs during routine dipping should take due account of exposure to concentrate dip as well as to the dilute dip wash. The observed use of recommended protective clothing by most subjects was insufficient to allow a proper empirical assessment of its effectiveness.

An epidemiological study of the relations between exposure to organophosphate pesticides and indices of chronic peripheral neuropathy and neuropsychological abnormalities in sheep farmers and dippers

OBJECTIVES

To investigate the hypothesis that chronic low level exposure to organophosphates (OPs) in sheep dips is related to clinically detectable measures of polyneuropathy.

METHODS

The design was a cross sectional exposure-response study of sheep dippers and other non-exposed groups. The study group consisted of 612 sheep dipping farmers, 53 farmers with no sheep dipping experience, and 107 ceramics workers. Retrospective exposure information was obtained by questionnaire based on stable and easily identifiable features of sheep dipping found during the first phase of the study; in particular, estimates of handling concentrate and splashing with dilute dip. Neurological assessments were based on a standard neuropathy symptoms questionnaire, and thermal and vibration quantitative sensory tests.

RESULTS

Adjusted for confounders there was a weak positive association between cumulative exposure to OPs and neurological symptoms, the significance of which was dependent on the inclusion of a few individual workers with extremely high exposure. There was no evidence of an association between cumulative exposure and the thermal or vibration sensory thresholds. However, separating the effects of exposure intensity and duration showed a higher prevalence of symptoms, primarily of a sensory type, among sheep dippers who handled the OP concentrate. There was also evidence that sensory and vibration thresholds were higher among concentrate handlers, the highest exposed group of dippers.

CONCLUSIONS

The findings showed a strong association between exposure to OP concentrate and neurological symptoms, but a less consistent association with sensory thresholds. There was only weak evidence of a chronic effect of low dose cumulative exposure to OPs. It is suggested that long term health effects may occur in at least some sheep dippers exposed to OPs over a working life, although the mechanisms are unclear.

A review of multiple chemical sensitivity

OBJECTIVE

To review critically the scientific literature on multiple chemical sensitivity (MCS). Definitions of MCS vary but, for this review, a broad definition of MCS was adopted as symptoms in more than one organ system elicited by various unrelated chemicals at very low levels of exposure.

METHODS

A systematic literature search identified several hundred references from which key papers were selected. Two questions are considered, does MCS exist and what causes MCS.

RESULTS AND CONCLUSIONS

Despite extensive literature on the existence of MCS, there is no unequivocal epidemiological evidence; quantitative exposure data are singularly lacking; and qualitative exposure data are, at best, patchy. There is also some evidence to suggest that MCS is sometimes used as an indiscriminate diagnosis for undiagnosed disorders. Despite this, the collated evidence suggests that MCS does exist although its prevalence generally seems to be exaggerated. Many causal mechanisms have been proposed, some suggesting a physical origin--such as MCS reflecting an immunological overload (total body load)--others favouring a psychological basis--such as MCS symptoms being evoked as part of a conditioned response to previous trauma. The available evidence seems most strongly to support a physical mechanism involving sensitisation of part of the midbrain known as the limbic system. However, it is increasingly being recognised that the psychological milieu of a person can considerably influence physical illness, either through generating a predisposition to disease or in the subsequent prognosis. Work is needed to establish the prevalence of MCS and to confirm or refute selected causal mechanisms.

A prospective study of BCG given to young children in Agra, India--a region of high contact with environmental mycobacteria

A multiple skin test survey of school children (aged 5-15 years) living in Agra, India showed very high levels of sensitisation to numerous species of mycobacteria and little difference in tuberculin positivity between those with and without BCG scars. A total of 136 children aged 3 months to 8 years, living in Agra, were skin tested with Tuberculin and Leprosin A and examined for scars of previous BCG vaccination. Of those who had not previously received BCG and who had responses to Tuberculin of zero or less than 5 mm induration, 109 were offered BCG vaccination: 107 accepted and as many of them as possible were followed up with repeat skin testing 1 and 2 years later. The results are discussed in relation to the background of environmental sensitisation. A comparison is made with the data obtained from other places, particularly the Lebanon, where there is little sensitisation from the environment. Although the high level of Tuberculin conversion achieved after BCG suggested that the vaccine might have an important protective effect, the large size of Tuberculin responses in comparison with those obtained in the UK was worrying. Evidence was obtained suggesting that sensitisation to mycobacteria may occur in very young children which is not detected by the Tuberculin test, but which influences responses to BCG vaccination.