Neuropathic pain following spinal cord injury: what we know about mechanisms, assessment and management

BACKGROUND

In biology, it is easy to understand how a damaged functional system may generate wrong signals, but why this should happen when the system is disconnected is less clear. For this reason, among other pain syndromes, neuropathic pain (NP) following spinal cord injury (SCI) leaves most questions unanswered.

AIMS AND METHODS

Our purpose is to review current knowledge on NP after SCI, focusing on the mechanisms, assessment and management of the syndrome.

RESULTS

The mechanisms responsible for NP following SCI are poorly understood: NP is classically considered a "central pain syndrome" but recent evidence from experimental models reveals a possible "peripheral sensitization". Assessment of NP following SCI is well-established: in addition to clinical evaluation and self-reported scales, many neurophysiological, radiological and microscopic investigations may be performed. The management of NP following SCI is very difficult: evidence of effective drugs is lacking and alternative new treatment approaches yield different outcomes.

CONCLUSIONS

Recently clinical and instrumental tools have increased our knowledge on NP, suggesting that the discovery of new treatment agents will depend on an explanation of what changes after SCI: future research must point in this direction.

Environmental microbial contamination in dental setting: a local experience

INTRODUCTION

Patients and operators are exposed during dental practice to an infective risk, which derives especially from microorganisms suspended in aerosols. Environmental microbiological monitoring in dental settings represents a good instrument to detect critical situations.

METHODS

In order to investigate environmental microbial contamination level in a local reality, we analyzed water, air and surfaces samples of a community-based dental facility by using protocol and threshold values proposed in a recent multicenter study carried out by the Italian Society of Hygiene, Preventive Medicine and Public Health (S.It.I.) working group "Hygiene in Dentistry". Microbial contamination was assessed in the same room for 4 non-consecutive weeks during all the five working days, before and at the end of the daily activity. Air was sampled also during clinical activity, through both active and passive sampling systems.

RESULTS

Contamination of water showed a decrease during activities, while a decrease in air contamination was registered only at the end of the day. Passive sampling values resulted more often above threshold values adopted. At the same time, surfaces contamination increases at the end of the activity. It seems that in the dental clinic analyzed microbial buildup represents the higher critical element. No differences have been registered among the different days of the week.

DISCUSSION

Our study highlights the need to improve disinfection procedures and air treatment systems in the considered environment. Microbiological monitoring could represent an important element to detect the presence of risk factors and to adopt control measures.

Autosomal recessive hereditary spastic paraplegia with thin corpus callosum: a novel mutation in the SPG11 gene and further evidence for genetic heterogeneity

BACKGROUND AND PURPOSE

Autosomal Recessive Hereditary Spastic Paraplegia with Thin Corpus Callosum (AR-HSPTCC) is a clinically and genetically heterogeneous complicated form of spastic paraplegia. Two AR-HSPTCC loci have been assigned to chromosome 15q13-15 (SPG11) and chromosome 8p12-p11.21 respectively. Mutations in the SPG11 gene, encoding the spatacsin protein, have been found in the majority of SPG11 families. In this study, involvement of the SPG11 or 8p12-p11.21 loci was investigated in five Italian families, of which four consanguineous.

METHODS

Families were tested for linkage to the SPG11 or 8p12-p11.21 loci and the SPG11 gene was screened in all the affected individuals.

RESULTS

Linkage was excluded in the four consanguineous families. In the only SPG11-linked family the same homozygous haplotype 4.2 cM across the SPG11 locus was shared by all the three affected siblings. A novel c.2608A>G mutation predicted to affect the splicing was found in exon 14 of the SPG11 gene.

DISCUSSION

This collection of families contributes to highlight the intra and inter locus heterogeneity in AR-HSPTCC, already remarked in previous reports. In particular, it confirms heterogeneity amongst Italian families and reports a new mutation predicted to affect splicing in the spatacsin gene.

Development of a disability scale for myotonic dystrophy type 1

OBJECTIVES

Myotonic dystrophy type 1 (DM1) is a multisystem disorder. Many tests in the literature have evaluated single aspects of DM1 patients, mainly focusing on muscular impairment, without an overall quantification of the different disease-specific neurological features. We developed and validated a new functional scale for DM1 patients based on neuromuscular impairment (NI) and disability.

MATERIALS AND METHODS

Thirty-three patients were tested in basal condition, 18 were re-evaluated after therapeutic intervention with mexiletine, and 13 at one year follow-up without treatment. The scale includes 21 ordinal items in four areas: neuropsychology, motricity, myotonia and daily life activities. We evaluated inter- and intra-observer reliability (intraclass correlation coefficient, ICC and Spearman correlations, respectively), internal consistency (Cronbach's alpha), external validity (Spearman correlations between each area and other clinical and objective measurements and scales), and sensitivity to clinical changes after treatment or at follow-up.

RESULTS

Our analysis provided good results for inter-observer agreement (ICC = 0.72-0.97), intra-observer reliability, and internal consistency for all areas (Cronbach's α > 0.73). Total score and single area subscores were significantly correlated to objective measurements, disease duration and multisystem involvement. Finally, the scale was sensitive to clinical changes disclosing a significant improvement after treatment in the items assessing myotonia, and also to disease progression showing a significant worsening in all areas but myotonia in untreated patients.

DISCUSSION

Our scale provides a new practical measure to evaluate NI and disability of DM1 patients. Further longitudinal studies are warranted to confirm its reliability in tracking disease progression and severity over a longer period of time.

Muscle sympathetic response to arousal predicts neurovascular reactivity during mental stress

Mental stress often begins with a sudden sensory (or internal) stimulus causing a brief arousal reaction, and is followed by a more long lasting stress phase. Both arousal and stress regularly induce blood pressure (BP) increases whereas effects on muscle sympathetic nerve activity (MSNA) are variable. Here we have compared responses of MSNA and BP during arousal induced by an electrical skin stimulus and mental stress evoked by a 3 min paced auditory serial arithmetic test (PASAT) in 30 healthy males aged 33 ± 10 years. In addition, recordings were made of ECG, respiratory movements, electrodermal activity and perceived stress. We also monitored corresponding effects of a cold test (CT: 2 min immersion of a hand in ice water). The arousal stimulus evoked significant inhibition of one or two MSNA bursts in 16 subjects, who were classified as responders; the remaining 14 subjects were non-responders. During mental stress responders showed a significant decrease of MSNA and a lesser BP increase compared to non-responders. In non-responders MSNA was unchanged or increased. Perceived stress was higher in non-responders (P = 0.056), but other measures were similar in the two groups. In non-responders mental stress and the cold test induced increases of BP that lasted throughout the subsequent rest period. During the cold test MSNA and BP increased equally in responders and non-responders. In the whole group of subjects, there was a significant correlation (r = 0.80, P < 0.001) between MSNA responses induced by arousal and by mental stress but not between responses evoked by arousal and the cold test (r < 0.1, P > 0.6). Additionally arousal-induced MSNA change was positively correlated with blood pressure changes during MS (systolic BP: r = 0.48; P < 0.01; diastolic BP: r = 0.42; P < 0.05) but not with blood pressure changes during CT. We conclude that in males the MSNA response to arousal predicts the MSNA and BP responses to mental stress.

Loss of temporal retinal nerve fibers in Parkinson disease: a mitochondrial pattern?

BACKGROUND AND PURPOSE

Optic nerve involvement is frequent in mitochondrial disease, and retinal abnormalities are described in Parkinson's disease (PD).

METHODS

We evaluated retinal nerve fiber layer (RNFL) thickness by optical coherence tomography in 43 patients with PD and in 86 age-matched controls. We considered separately the eyes ipsilateral and contralateral to the most affected body side in patients with PD. ancova analysis, Pearson test, and multiple regression analysis were used (P < 0.05).

RESULTS

Patients with PD showed significantly thinner temporal RNFL thickness compared to controls (P = 0.004), more evident in the eye contralateral to the most affected body side. Average RNFL thickness significantly correlated with age in both controls and patients with PD (P-values ranging from 0.001 to 0.019), whereas in patients with PD RNFL thickness did not correlate with clinical variables.

CONCLUSIONS

Our study reveals a loss of retinal nerve fibers in the temporal quadrant in PD, which is typically susceptible in mitochondrial optic neuropathies.

Environmental risk factors and clinical phenotype in familial and sporadic primary blepharospasm

BACKGROUND

Although environmental and genetic factors may contribute to the etiology of blepharospasm, their relative contribution in causing familial and sporadic blepharospasm is unknown.

METHODS

First-degree relatives of 122 patients with primary blepharospasm were examined with a validated 2-step diagnostic procedure, including a screening questionnaire and examination of some relatives. Examiners were blinded to the questionnaire data for family history of probands. Data for demographic and clinical features, prior ophthalmologic complaints, and nondecaffeinated coffee intake were collected from probands before family investigation.

RESULTS

Dystonia was diagnosed in 27 relatives from 23 families (20% rate of family history for dystonia). No significant differences were found between familial and sporadic cases in the frequency of coffee drinking and eye diseases or in sex, age at onset, or tendency to spread. Multivariable conditional logistic analysis testing of 67 case patients and 127 family-matched unaffected siblings yielded a significant positive association between blepharospasm and prior eye diseases (adjusted odds ratio [OR] 2.5; 95% confidence interval [CI] 1.1-6.1; p = 0.03) and a significant inverse association between case status and ever coffee drinking (adjusted OR 0.23; 95% CI 0.1-0.8; p = 0.02).

CONCLUSIONS

The new information from this large family-based study on primary blepharospasm strongly supports eye diseases and coffee as risk factors for blepharospasm. The finding that the 2 environmental exposures exerted a similar influence on familial and sporadic blepharospasm, together with the convergent phenotypic expression in familial and sporadic cases, implies that familial and sporadic blepharospasm probably share a common etiologic background.

Autonomic innervation in multiple system atrophy and pure autonomic failure

BACKGROUND

Pure autonomic failure (PAF) and multiple system atrophy (MSA) are both characterised by chronic dysautonomia although presenting different disability and prognosis. Skin autonomic function evaluation by indirect tests has revealed conflicting results in these disorders. Here, the authors report the first direct analysis of skin sympathetic fibres including structure and function in PAF and MSA to ascertain different underlying autonomic lesion sites which may help differentiate between the two conditions.

METHODS

The authors studied eight patients with probable MSA (mean age 60±5 years) and nine patients fulfilling diagnostic criteria for PAF (64±8 years). They underwent head-up tilt test (HUTT), extensive microneurographic search for muscle and skin sympathetic nerve activities from peroneal nerve and punch skin biopsies from finger, thigh and leg to evaluate cholinergic and adrenergic autonomic dermal annexes innervation graded by a semiquantitative score presenting a high level of reliability.

RESULTS

MSA and PAF patients presented a comparable neurogenic orthostatic hypotension during HUTT and high failure rate of microneurographic trials to record sympathetic nerve activity, suggesting a similar extent of chronic dysautonomia. In contrast, they presented different skin autonomic innervation in the immunofluorescence analysis. MSA patients showed a generally preserved skin autonomic innervation with a significantly higher score than PAF patients showing a marked postganglionic sympathetic denervation. In MSA patients with a long disease duration, morphological abnormalities and/or a slightly decreased autonomic score could be found in the leg reflecting a mild postganglionic involvement.

CONCLUSION

Autonomic innervation study of skin annexes is a reliable method which may help differentiate MSA from PAF.

Emamectin benzoate (Affirm). a modern insecticide for the control of lepidoptera larvae on fruits, grapes and vegetables crops

Emamectin benzoate (Affirm) is a novel insecticide with potent efficacy against many specie of lepidoptera which are damaging fruits and leaves of agricultural crops. The active ingredient belongs to the naturally derived chemical group of avermectine, causing paralysis of lepidoptera larvae due to the activation of chloride channel at nerves level. Affirm is acting mainly through ingestion, due to its mode of action and fast activity, it is effective at very low rates and on all instars stages. It has been developed for the use on pomefruits, stonefruits, grapes and a broda range of vegetables crops at a rate range of 1.5 to 3 g ai/100L. The product shows translaminar activity and rapid degradation on leaf surface; therefore the active ingredient breaks down in a very short time to sublethal doses for most beneficials organisms living on the vegetation. The short rentry time, generally 24 hours for beneficials and impollinators, makes Affirm compatible for IPM programme in orchards and greenhouses. Also the residue profile is very favourable, leading to a very low maximum residue level and short preharvest interval in all edible crops.

Lower limb involvement in adult-onset primary dystonia: frequency and clinical features

BACKGROUND AND PURPOSE

Despite the growing number of reports describing adult-onset primary lower limb dystonia (LLD) this entity has never been systematically evaluated in the general population of patients with primary adult-onset dystonia.

METHODS

From outpatients with adult-onset primary dystonia attending nine Italian University centres for movement disorders we consecutively recruited 579 patients to undergo a standardized clinical evaluation.

RESULTS

Of the 579 patients assessed, 11 (1.9%) (8 women, 3 men) had LLD, either alone (n = 4, 0.7%) or as part of a segmental/multifocal dystonia (n = 7, 1.2%). The age at onset of LLD (47.9 +/- 17 years) was significantly lower than the age at onset of cranial dystonias (57.9 +/- 10.7 years for blepharospasm, and 58.9 +/- 11.8 years for oromandibular dystonia) but similar to that of all the other adult-onset primary dystonias. The lower limb was either the site of dystonia onset (36.4%) or the site of dystonia spread (63.6%). In patients in whom LLD was a site of spread, dystonia seemed to spread following a somatotopic distribution. Only one patient reported a recent trauma involving the lower limb whereas 36.4% of the patients reported pain at the site of LLD. Only 64% of our patients needed treatment for LLD, and similarly to previously reported cases, the most frequently tried treatments was botulinum toxin and trihexyphenidyl.

CONCLUSION

The lower limb is an uncommon but possible topographical site of dystonia in adulthood that should be kept in consideration during clinical evaluation.

Risk factors for type 2 diabetes in women attending menopause clinics in Italy: a cross-sectional study

OBJECTIVE

To analyze risk factors for type 2 diabetes among women attending menopause clinics in Italy for counselling about the menopause.

SUBJECTS

Women attending a network of first-level outpatient menopause clinics in Italy for general counselling about menopause or treatment of menopausal symptoms.

METHODS

Cross-sectional study with no exclusion criteria. Type 2 diabetes was defined according to National Diabetes Data Groups Indications and the fasting blood glucose at an oral glucose tolerance test within the previous year.

RESULTS

Out of the 44 694 considered in this analysis, 808 had a diagnosis of diabetes type 2 (1.8%). In comparison with women aged < 50 years, the multivariate odds ratios (OR) of type 2 diabetes were 1.31 (95% confidence interval (CI), 0.99-1.74) for women aged 50-52 years, 1.66 (95% CI, 1.27-2.17) at 53-56 years and 2.84 (95% CI, 2.20-3.67) in women aged > or = 57 years. Type 2 diabetes was less frequently reported in more educated women (OR high school/university vs. primary school = 0.44 (95% CI, 0.36-0.55)). Being overweight was associated with an increased risk of type 2 diabetes. In comparison with women reporting a low level of physical activity, the multivariate OR of type 2 diabetes was 0.67 (95% CI, 0.54-0.84) for women reporting regular physical activity. In comparison with premenopausal women, the multivariate OR of type 2 diabetes was 1.38 (95% CI, 1.03-1.84) in women with natural menopause. This finding was present also after allowing for the potential confounding effect of age. The multivariate OR of diabetes for users of hormonal replacement therapy was 0.58 (95% CI, 0.46-0.73).

CONCLUSIONS

This large cross-sectional study suggests that postmenopausal women are at higher risk of type 2 diabetes after allowance for the effect of age. Other main determinants of risk of type 2 diabetes in women around menopause were low socioeconomic status and being overweight. Diabetes was found less frequently in those taking hormone replacement therapy.

Isolated generalised anhidrosis induced by postganglionic sympathetic skin nerve fibre degeneration: an incomplete Ross syndrome?

Ross syndrome is characterised by tonic pupil, areflexia and anhidrosis, and the underlying lesion affects postganglionic skin sympathetic nerve fibres. We describe a 51-year-old man who had complained of anhidrosis since adolescence, at which time this problem was limited to the lower arms. The thermoregulatory sweating test disclosed generalised anhidrosis (GA) except for two small skin areas that were located in the right palm and left neck. Immunofluorescence analysis disclosed no cholinergic sudomotor fibres around the sweat glands of non-sweating skin areas, which were evident although sparse and deranged in the sweating site. In our patient, GA was induced by degeneration of postganglionic sympathetic skin nerve fibres, as found in Ross syndrome, although his clinical picture was incomplete as it lacked tonic pupil and areflexia. Isolated GA induced by degeneration of postganglionic sympathetic nerve fibers, directly evaluated by skin biopsy, has not previously been described.