Isolated Oculomotor Neuritis After Dengue Fever

ABSTRACT

We report a rare case of isolated partial left III cranial nerve palsy due to inflammatory oculomotor neuritis after dengue fever with unique neuro-imaging findings of enhancement seen along the entire course of the oculomotor nerve.

Anti-natural octyl disaccharide-leprosy IDRI diagnostic (NDO-LID) antibodies as indicators of leprosy reactions and neuritis

Background

Leprosy is a complex infectious and neurological disease caused by Mycobacterium leprae. Nerve damage is related to immunological hypersensitivity responses known as leprosy reactions (LRs). Diagnostic tools to predict LRs are not available. We hypothesized that natural octyl disaccharide-leprosy IDRI diagnostic (NDO-LID) would be helpful as an indicator of LRs and neuritis.

Methods

To assess the utility of NDO-LID in indicating reactions, ELISA were used to detect specific antibodies in serum samples from 80 Colombian leprosy patients (40 with and 40 without history of LRs). Responses were detected using a range of detection reagents detecting IgG, IgM or both isotypes.

Results

Patients with a history of LRs had an increased seropositivity rate for anti-NDO-LID antibodies compared to patients without (anti-NDO-LID protein A [p=0.02], IgG anti-NDO-LID [p=0.01] and IgM anti-NDO-LID [p=0.01]). Further analyses of patients with a history of LRs indicated that both seropositivity rate and magnitude of responses were elevated among patients with neuritis versus those without neuritis (anti-NDO-LID protein A [p=0.03], IgG anti-NDO-LID [p=0.001] and IgM anti-NDO-LID [p=0.06]).

Conclusions

Our data indicate that testing for serum anti-NDO-LID antibodies can be a useful screen to identify patients at risk of developing LRs and neuritis.

Ophthalmoplegic Migraine: Inflammatory Neuropathy with Secondary Migraine?

Background:

This critical review provides a summary of the clinical presentation, neuroimaging, treatment and prognosis in pediatric ophthalmoplegic migraine (OM). The features of OM are not in keeping with its classification as a migraine-variant.

Method:

We review 3 new and 37 reported pediatric OM cases.

Results:

Headache was an inconsistent feature, with 25% patients showing no evidence of pain at the initial OM episode.

Patients demonstrated:

1) prolonged time for symptom resolution to occur (median time 3 weeks); 2) tendency for recurrent episodes to have more severe and persistent nerve involvement; 3) evidence of permanent neurological sequelae with recurrent episodes (30% of patients); 4) rapid improvement and shortened duration with corticosteroid therapy and; 5) transient, reversible MRI contrast enhancement of the affected cranial nerve (86% of patients). These features would not be expected in primary migraine headache.

Conclusion:

A detailed understanding of the natural history of OM is essential for the clinical. This review provides support that OM may result from cranial nerve inflammation with headache a secondary and later feature of this condition.

Self-awareness of foot health status in patients with Type 2 diabetes: the Fremantle Diabetes Study Phase II

AIMS

To determine self-awareness of diabetes-related foot problems and its associates in a community-based cohort of people with Type 2 diabetes.

METHODS

A survey concerning diabetic foot problems was administered to 358 consecutive patients with Type 2 diabetes [mean ± SD age 67.4 ± 10.8 years, 56.1% males, median (interquartile range) diabetes duration 9.0 (3.9-16.8) years] attending for detailed clinical, biochemical and questionnaire assessment as part of the longitudinal observational Fremantle Diabetes Study Phase II.

RESULTS

Compared with the 213 patients (59.5%) who considered their feet to be normal, the 145 (40.5%) who considered their feet to be abnormal were older, had longer diabetes duration and were more likely to have sensory neuropathic symptoms and self-reported poor circulation (P < 0.001). In those who considered their feet to be normal, 67.9% had peripheral sensory neuropathy (score >2/8 on the Michigan Neuropathy Screening Instrument clinical portion), 9.9% had an ankle-brachial index < 0.9, 6.1% had both peripheral sensory neuropathy and an ankle-brachial index < 0.90, and 86.9% had one or more features on inspection, such as deformity, dry skin, callus and fissures that could facilitate more serious complications, despite the majority having had at least one foot examination by a healthcare professional in the previous year.

CONCLUSIONS

Self-assessment of diabetes-related foot problems by patients in the Fremantle Diabetes Study Phase II was unreliable. The present data suggest that self-perceived foot health should be assessed together with foot examination findings. Intensive education and monitoring may be necessary in those who consider their feet to be normal but who have neurovascular, structural and/or other precursors of serious foot pathology.

Role of capsaicin-sensitive peripheral sensory neurons in anorexic responses to intravenous infusions of cholecystokinin, peptide YY-(3-36), and glucagon-like peptide-1 in rats

Cholecystokinin (CCK)-induced suppression of feeding is mediated by vagal sensory neurons that are destroyed by the neurotoxin capsaicin (CAP). Here we determined whether CAP-sensitive neurons mediate anorexic responses to intravenous infusions of gut hormones peptide YY-(3-36) [PYY-(3-36)] and glucagon-like peptide-1 (GLP-1). Rats received three intraperitoneal injections of CAP or vehicle (VEH) in 24 h. After recovery, non-food-deprived rats received at dark onset a 3-h intravenous infusion of CCK-8 (5, 17 pmol·kg⁻¹·min⁻¹), PYY-(3-36) (5, 17, 50 pmol·kg⁻¹·min⁻¹), or GLP-1 (17, 50 pmol·kg⁻¹·min⁻¹). CCK-8 was much less effective in reducing food intake in CAP vs. VEH rats. CCK-8 at 5 and 17 pmol·kg⁻¹·min⁻¹ reduced food intake during the 3-h infusion period by 39 and 71% in VEH rats and 7 and 18% in CAP rats. In contrast, PYY-(3-36) and GLP-1 were similarly effective in reducing food intake in VEH and CAP rats. PYY-(3-36) at 5, 17, and 50 pmol·kg⁻¹·min⁻¹ reduced food intake during the 3-h infusion period by 15, 33, and 70% in VEH rats and 13, 30, and 33% in CAP rats. GLP-1 at 17 and 50 pmol·kg⁻¹·min⁻¹ reduced food intake during the 3-h infusion period by 48 and 60% in VEH rats and 30 and 52% in CAP rats. These results suggest that anorexic responses to PYY-(3-36) and GLP-1 are not primarily mediated by the CAP-sensitive peripheral sensory neurons (presumably vagal) that mediate CCK-8-induced anorexia.

Insulin neuritis and diabetic cachectic neuropathy: a review

Diabetic patients can be affected by a wide range of peripheral nerve disorders, the rarer of which are often poorly recognised and understood. "Insulin neuritis" or "treatment induced neuropathy" is a reversible disorder characterised by acute severe distal limb pain, peripheral nerve fibre damage and autonomic dysfunction, preceded by a period of rapid glycaemic control. The condition has been reported in both type 1 and type 2 diabetics treated with insulin or oral hypoglycaemic agents who typically have a history of poor glycaemic control. Pathogenesis of the condition and its associated pain is poorly understood, with proposed mechanisms including endoneurial ischaemia, hypoglycaemic microvascular neuronal damage and regenerating nerve firing. Pain can affect other areas including the trunk and abdomen, or be more generalised. "Diabetic neuropathic cachexia" is a rare disorder associated with poor diabetic control that presents with large amounts of unintentional weight loss associated with an acute symmetrical painful peripheral neuropathy without weakness. Pain is characteristically burning in nature with predominant lower limb involvement and allodynia. The disorder can also affect type 1 and type 2 diabetics and occur irrespective of the duration of their diabetes. Depression and in males, impotence, appear to be common, although other autonomic features can be present. Typically it has a monophasic course but has been reported to be recurrent. As with insulin neuritis, this condition is reversible over weeks to months after adequate diabetic control. For both disorders, the pain can be treatment resistant despite the use of multiple analgesics.

[Diagnosis and treatment of upper arm radial neuritis by ultrasonography]

OBJECTIVE

To evaluate the application of ultrasonography in diagnosis and treatment of the upper arm radial neuritis.

METHODS

From 2005.12 to 2011.7, 10 patients of the upper arm radial neuritis were selected and included 6 males and 4 females with an average age of 32 years old ranging from 20 to 40 years. The course of disease ranged from 4 months to 2 years. All patients feel pain on the outside of upper arm. Medical examination showed Tinel's sign masculine, and the muscle force included extension of wrist and fingers were reduced. Upper arm radial neuritis were diagnosed by clinical sign and medical examination. All patients underwent ultrasonography examination, electrophysiology examination and operation. The ultrasonography were compared to the results of electrophysiology examination,and ultrasonography were compared to intra-operative findings and pathology examination.

RESULTS

The ultrasound images showed average diameter of affected limb radial nerve were (0.29+/-0.04) cm, average area were (0.23+/-0.05) cm2, and all of these were greater than uninjured side. Ultrasonograghic findings and orientation of radial neuritis were consistent with intra-operative findings,and the results of ultrasonography were consistent with the results of pathology examination.

CONCLUSION

Ultrasonography examination provide morphological evidence for the diagnosis and treatment of the upper arm radial neuritis.

Complications of femoral nerve block for total knee arthroplasty

Preemptive and multimodal pain control protocols have been introduced to enhance rehabilitation after total knee arthroplasty (TKA). We determined the complication rate associated with preoperative femoral nerve block (FNB) for TKA. Among 1018 TKA operations, we performed 709 FNBs using a single-injection technique into the femoral nerve sheath and confirming position with nerve stimulation before induction. After TKA, weightbearing as tolerated was initiated using a walker or crutches on postoperative Day 1. Twelve patients (1.6%) treated with FNB sustained falls, three (0.4%) of whom underwent reoperations. Five patients had postoperative femoral neuritis, which may have been secondary to the block. One patient had new onset of atrial fibrillation after FNB, and the TKA was postponed. Femoral nerve block before TKA is not a harmless intervention. We recommend postoperative protocols be modified for patients who have FNB to account for decreased quadriceps function in the early postoperative period, which can lead to falls.

LEVEL OF EVIDENCE

Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

[Wartenberg's migrant sensory neuritis]

Two patients with progressive multifocal sensory symptoms and signs are described. The sensory disturbances were bilateral, and mainly arose in the territory of the radial nerves. Stretching or touching the wrist elicited electrical sensations in the fingers. The diagnosis of Wartenberg's migrant sensory neuritis (WMSN) was suggested. Nerve conduction studies confirmed the presence of peripheral nerve affection, and the electrophysiological abnormalities corresponded to the pattern and progression of clinical abnormalities.

Clinical and nerve conduction studies in female patients with diabetic dermopathy

This study aims to assess the clinical and electrophysiological characteristics of diabetic polyneuropathy (PNP) in female patients. We investigated clinical and electrophysiological features in 175 female patients with diabetes mellitus to compare those with PNP only, diabetic dermopathy (DD), or diabetic foot (DF). Among clinical features, the loss of deep tendon reflexes, the presence of negative sensory symptoms, superficial sensory loss, and the loss of vibration sense were more common in DD patients than PNP patients. As compared with DD patients, the presence of skin atrophy, superficial and positive sensory symptoms were more common in DF patients. Neuropathic symptom and disability scores were significantly higher in DD and DF patients than PNP patients. In the electrophysiological studies, the only significant difference was observed in the mean distal latencies for ulnar nerves, which were longer in DD patients as compared with PNP patients, but similar between DD and DF patients. All other parameters failed to show significant difference among patients, though values for DD patients lied in between PNP and DF patients. Carpal tunnel syndrome was present in 45% of PNP patients, 63.8% of DD patients, and 50% of DF patients (P = 0.031). Our results suggest that female patients with diabetic dermopathy might have a more severe sensorial neuropathy than patients without these skin lesions.

Enteric ganglioneuritis and abnormal interstitial cells of Cajal: features of inflammatory bowel disease

BACKGROUND

An increased prevalence of irritable bowel syndrome (IBS) and disturbances in cardiac and blood pressure reflexes have been described in patients with Crohn's disease (CD) and ulcerative colitis (UC). These features could be due to abnormalities in the gastrointestinal neurotransmission. The aims of this study were to examine whether histopathologic changes in the enteric nervous system correlate with disturbances in cardiac and blood pressure reflexes and the occurrence of IBS- and dyspepsia-like symptoms in these patients.

METHODS

Thirty patients with CD and UC with bowel resection were examined by deep-breathing and orthostatic tests. The resection specimens were evaluated histologically regarding visceral neuro- or myopathy. All medical records were studied for treatment and clinical course.

RESULTS

Ganglioneuritis was observed in 11 of 19 patients with CD and in 5 of 11 with UC. Only patients with CD had ganglioneuritis in the small intestine. Moreover, in CD the interstitial cells of Cajal (ICCs) in the small bowel showed atrophy and vacuolar degeneration, along with a reduced number of cells (P = 0.005). In UC the colonic ICCs were hyperplastic (P = 0.05) without signs of degeneration. The indices of deep-breathing and orthostatic tests were impaired, except in CD with ganglioneuritis, who showed normal test values. There were no correlations between histopathologic alterations versus IBS and dyspepsia.

CONCLUSIONS

Visceral ganglioneuritis and pathologic ICCs were observed in patients with CD and UC. However, these histopathologic abnormalities could not be related to the clinical or autonomic features of the disease.

Impact of disease characteristics on the efficacy of duloxetine in diabetic peripheral neuropathic pain

OBJECTIVE

To evaluate the impact of baseline disease variables related to diabetes and diabetic neuropathy severity on efficacy and safety of duloxetine in the management of diabetic peripheral neuropathic pain.

RESEARCH DESIGN AND METHODS

The impact of baseline conditions was evaluated using the data from three pooled placebo-controlled studies for combined duloxetine, doses of 60 mg q.d. and 60 mg b.i.d., versus placebo. The primary efficacy measure was the weekly mean of 24-h average pain severity, and night pain was the secondary measure. Safety and tolerability were assessed.

RESULTS

There were no significant (P > 0.10) interactions of treatment by age (< 65 or > or = 65 years), type of diabetes (type 1 or type 2), duration of diabetes (median split < 9.18 or > or = 9.18 years), duration of diabetic neuropathy (< 2, 2 to < 6, or > or = 6 years), severity of diabetic neuropathy (baseline Michigan Neuropathy Screening Instrument score < 5 or > or = 5), baseline A1C level (median split < 7.6 or > or = 7.6%), or baseline insulin use (yes/no). Significant interactions for both pain measures were observed in baseline pain subgroups (Brief Pain Inventory average pain, > or = 6 and < 6). Duloxetine was more effective in the subgroup with more pain. No significant association was found between any other subgroups (P > 0.10). Significant interactions (P < 0.1) occurred with treatment-emergent adverse events when stratified by subgroups.

CONCLUSIONS

Pain severity but not variables related to diabetes or neuropathy may predict the effects of duloxetine in diabetic peripheral neuropathic pain. The efficacy of duloxetine is related to the initial pain severity and is generalizable across a broad spectrum of diabetic patients, including those with the highest severity of diabetes or neuropathy.

Impaired skin microvascular reactivity in painful diabetic neuropathy

OBJECTIVE

The pathogenesis of painful diabetic neuropathy (PDN) is not clear. Following our in vivo observations of increased sural nerve epineurial blood flow in patients with PDN, we investigated the cutaneous microcirculation of the foot by laser Doppler flowmetry to determine if the epineurial findings were just confined to the nerve or more widespread in other vascular beds.

RESEARCH DESIGN AND METHODS

We measured foot skin vasodilator responses to acetylcholine (Ach) and sodium nitroprusside (SNP) and vasoconstrictor responses to sympathetic (deepest possible gasp) stimulation in 5 healthy control subjects, 10 non-neuropathic diabetic (NND) patients, 10 diabetic patients with painless neuropathy (PLDN), and 8 diabetic patients with PDN.

RESULTS

In PDN, there were significantly reduced responses to Ach (ANOVA P = 0.003) and vasoconstrictor inspiratory gasp (ANOVA P < 0.001) but not to SNP (NS). Post hoc analysis showed significant differences in Ach-induced vasodilation between PDN and nondiabetic control subjects (P < 0.05) as well as between PDN and NND (P < 0.05) but not PDN and PLDN (NS). There were no significant differences for SNP-induced vasodilation. However, there were significant differences in the vasoconstrictor response between PDN and control, NND, and PLDN (P < 0.01).

CONCLUSIONS

We found an impairment of cutaneous endothelium-related vasodilation and C-fiber-mediated vasoconstriction in PDN. Inappropriate local blood flow regulation may have a role in the pathogenesis of pain in diabetic neuropathy. Prospective studies are required to determine the temporal relationship of these changes in relation to the emergence of neuropathic pain.

Effects of inflammatory cytokines IL-1beta, IL-6, and TNFalpha on the intracellular localization of retinoid receptors in Schwann cells

It was investigated whether retinoic acid (RA) and the proinflammatory cytokines IL-1beta, IL-6, and TNFalpha influence the intracellular distribution of retinoic acid receptors (RAR) and retinoid X receptors (RXR) in Schwann cells. This question arose because nuclear translocation of RARalpha, RXRalpha, and RXRbeta was observed after nerve injury, and because mutual interactions exist between the signal transduction pathways of RA and proinflammatory cytokines. Schwann cell primary cultures from the rat sciatic nerve were incubated with IL-1beta, IL-6, and TNFalpha, with all-trans RA and with a combination of IL-1beta and RA. After incubation periods ranging from 5 min to 5 h, the intracellular distributions of RARalpha, RARbeta, RXRalpha, and RXRbeta were analyzed. All three cytokines caused a shift of RARalpha from the cytosolic compartments into the cell nuclei. This was also observed with RA, and combining RA with IL-1beta produced an additive effect. IL-1beta and IL-6 also affected the distribution of RARbeta, although immunoreactivity of this receptor always remained stronger in the cytosol. No effect of the cytokines on RXRalpha or RXRbeta was observed, whereas RA treatment caused a stronger nuclear signal of both receptors. Effects on the subcellular localization of retinoid receptors may provide a link in a feedback loop between RA/RAR and cytokines.

Association of neural inflammation with hyperalgesia following spinal nerve ligation

AIM

To explain the variability in the behavioral response after spinal nerve ligation by investigating the relation between the development of neuropathic pain and the expression of inflammatory indicators, in dorsal root ganglia (DRG) and the spinal nerve.

METHODS

Ninety-six male Sprague-Dawley rats were randomly assigned to the modified spinal nerve ligation, sham, and control group. Testing for pain-related behavior identified rats that successfully developed neuropathic pain (responders) and those which did not (non-responders). The extent of neuroinflammation in the two groups was assessed by immunohistochemical staining of dorsal root ganglions glial fibrillary acid protein (GFAP), and rat C3 complement receptor (OX-42).

RESULTS

GFAP and OX-42 immunopositive cell density in the DRG and spinal nerve was significantly higher in hyperalgesic animals. DRG cell density was 3.96+/-0.68 cells/2500 microm2 in GFAP responders' group, compared with 2.76+/-0.75 cells/2500 microm2 in non-responders' group (Mann-whitney U test, Z=-3.956, P<0.001). OX-42 density was 7.71+/-1.03 cells/2500 microm2 in responders and 4.75+/-1.76 cells/2500 microm2 in non responders (Mann-whitney U test, Z=-2.572, P=0.01). Hyperalgesic behavior progressively increased during the testing period, although immunopositive cell density peaked on the fourth day post-injury and progressively decreased afterwards.

CONCLUSION

Our study suggests that inflammation has a decisive role in initiating neuropathic pain. Also, this study confirms that, for the sake of selecting appropriate subjects for mechanistic study, it is necessary to discriminate between experimental subjects that develop pain completely and those that do not.

Effect of leflunomide on the peripheral nerves in rheumatoid arthritis

BACKGROUND

The objective of this study was to determine the neurophysiological effects of leflunomide on peripheral nerves in rheumatoid arthritis.

METHODS

We conducted a prospective cohort trial of 32 patients with rheumatoid arthritis with 16 patients receiving leflunomide treatment and 16 receiving other disease-modifying anti-rheumatic drug therapies. Clinical, laboratory and neurophysiological measurements were used to determine the presence of a peripheral neuropathy in these patients at study entry and then after a further 3 and 6 months.

RESULTS

Fifty-four per cent of the leflunomide group and 8% of the control group had an increase in their neuropathy symptom score 6 months into the study (P = 0.01). No correlation was found between the electrophysiological findings and the clinical symptoms. There was no significant difference between the two groups in upper and lower limb sensory and motor amplitudes and conduction velocities recorded at 3 and 6 months. One patient developed both clinical and neurophysiological evidence of a peripheral neuropathy 5 months into the study that improved after cessation of leflunomide therapy and cholestyramine washout.

CONCLUSION

After 6 months of exposure we found that leflunomide was associated with an apparent increase in the clinical symptoms of peripheral neuropathy in patients with rheumatoid arthritis. These symptoms did not correlate with neurophysiological studies.

Activation of cyclin-dependent kinase 5 (Cdk5) in primary sensory and dorsal horn neurons by peripheral inflammation contributes to heat hyperalgesia

Cyclin-dependent kinase 5 (Cdk5) is a unique member of the CDK family. It is predominantly expressed in postmitotic neurons and has been implicated in neuronal plasticity. The present study showed that Cdk5 and p35 were expressed in primary sensory and dorsal horn neurons, while p25, an N-terminal truncated derivative of p35, could only be detected in the dorsal horn neurons. Importantly, in the case of control rats, the p35 protein level was much higher in small- and medium-diameter DRG neurons than it was in large neurons. Following CFA injection, Cdk5 activity was upregulated in both primary sensory and dorsal horn neurons. Cdk5 activation in DRG neurons required p35, whereas p25 was required in the dorsal horn. Intrathecal pretreatment with Roscovitine, a specific inhibitor of Cdk5 activity, and intrathecal delivery of the DN-Cdk5(N144) gene both alleviated CFA-induced heat hyperalgesia but not mechanical allodynia. In contrast, overexpression of Cdk5, p35 or p25 in primary sensory and dorsal horn neurons significantly enhanced heat hyperalgesia. We conclude that Cdk5/p35 and Cdk5/p25 complexes in primary sensory and dorsal horn neurons may potentially be involved in nociceptive transmission after inflammation and may be employed in synaptic plasticity underlying pain hypersensitization.

Inflammatory hyperalgesia: a role for the C-fiber sensory neuron cell body?

Peripheral nerve injury increases the chemosensitivity and excitability of injured afferents, resulting in ectopic activity arising from within dorsal root ganglia. Studies of dissociated sensory ganglion neurons in vitro suggest afferent somata might be sensitized by persistent inflammation. However, it is unknown whether this inflammation-induced sensitization is manifest in somata within the intact ganglia. To explore this possibility, intracellular electrophysiologic recording was used with a sciatic nerve-L4-dorsal root ganglia preparation to compare excitability and chemosensitivity of cutaneous C-fiber somata from control and inflamed rats. Cutaneous afferents were identified with the retrograde dye DiI. Excitability was assessed before and after the application of inflammatory soup (IS) containing bradykinin, serotonin, and prostaglandin E2 all at a pH of 7.0. Persistent inflammation decreased the excitability of cutaneous afferents in intact ganglia and had no significant influence on the magnitude of IS-induced increase in excitability. Opposite to the effects observed in intact ganglia, excitability was greater in dissociated cutaneous nociceptors obtained from inflamed rats, although the magnitude of the IS-induced increase in excitability was not significantly affected by inflammation. These results suggest that the cell bodies of putative cutaneous nociceptors in the intact ganglia contribute minimally to pain and hyperalgesia associated with persistent inflammation.

PERSPECTIVE

Results of the present study suggest that inflammation-induced changes in afferent somata are minimal. However, they also suggest that inflammatory mediator-induced increase in the excitability of sensory neuron somata might contribute to global changes in nociception observed under high systemic inflammatory mediator loads.

Role of spinal microglia in rat models of peripheral nerve injury and inflammation

Mounting evidence supports the hypothesis that spinal microglia modulate the development and maintenance of some chronic pain states. Here we examined the role of spinal microglia following both peripheral inflammatory insult and peripheral nerve injury. We observed significant ipsilateral dorsal horn microglia activation 2 weeks after injury and bilateral activation 50 days following nerve injury as well as 24 h following intraplantar zymosan but not intraplantar complete Freund's adjuvant (CFA). Ipsilateral but not contralateral microglia activation was associated with hind paw mechanical hyperalgesia. Spinal injection of the glial metabolic inactivator fluorocitrate attenuated ipsilateral hyperalgesia and bilateral spinal microglia activation after peripheral nerve injury. Intrathecal fluorocitrate reversed hyperalgesia after intraplantar zymosan and produced no reversal of CFA-induced hyperalgesia. These data suggest a role for spinal glia in the persistence of mechanical hyperalgesia following peripheral nerve injury. However, activation of spinal microglia contralaterally did not correlate to nociception. Furthermore, it would appear that the time course of microglia activation and their contribution to inflammatory pain is dependent on the inflammatory stimulus administered.

Changes in tracheo-bronchial sensory neuropeptide receptor gene expression pattern in rats with cisplatin-induced sensory neuropathy

An attenuated neurogenic broncho-constriction underpinned by a decrease in sensory neuropeptide release has been shown to be characteristic of cisplatin-induced neuropathy. The present work was to explore if beyond neuropeptide release, cisplatin at a treatment schedule attaining sensory neuropathy, produced changes in the expression of the receptors of sensory neuropeptides such as somatostatin, calcitonin gene-related peptide (CGRP) and substance P (SP) in bronchial tissue of the rat. Twenty-four Wistar rats were divided into three groups. The animals in the "Treatment groups 1 and 2" were given cisplatin (1.5mgkg(-1)) and mannitol (75mgkg(-1)) over 5 days. The rats in the "Control" group were given mannitol+isotonic saline. Four animals from each group were used to study the expression pattern of the neuropeptide receptors in bronchial tissue. The levels of somatostatin receptor 4 (SSTR 4), neurokinin 1 (NK1), neurokinin 2 (NK2) and CGRP receptor expression were examined by quantitative real time polymerase chain reaction (RT-PCR) method, 11 and 22 days after the last cisplatin/vehicle dose. The cisplatin treatment significantly increased plasma somatostatin immunoreactivity and the expression of SSTR4 receptor detected both on the 11th and 22nd post-treatment days with no change in either CGRP, NK1, and NK2 receptor gene expression or plasma CGRP and substance P levels. We conclude that cisplatin neuropathy is accompanied by an increase in plasma somatostatin immunoreactivity with an increase in SSTR4 expression in rats.

A controlled study of peripheral neuropathy after bariatric surgery

BACKGROUND

Although peripheral neuropathy (PN) occurs after bariatric surgery (BS), a causal association has not been established.

OBJECTIVES

To ascertain whether PN occurs more frequently following BS vs another abdominal surgery, to characterize the clinical patterns of PN, to identify risk factors for PN, and to assess if nerve biopsy provides pathophysiologic insight.

METHODS

Retrospective review identified patients with PN after BS. The frequency of PN was compared with that of an age- and gender-matched, retrospectively evaluated cohort of obese patients undergoing cholecystectomy.

RESULTS

Of 435 patients who had BS, 71 (16%) developed PN. Patients developed PN more often after BS than after cholecystectomy (4/126; 3%) (p < 0.001). The clinical patterns of PN were polyneuropathy (n = 27), mononeuropathy (n = 39), and radiculoplexus neuropathy (n = 5). Risk factors included rate and absolute amount of weight loss, prolonged gastrointestinal symptoms, not attending a nutritional clinic after BS, reduced serum albumin and transferrin after BS, postoperative surgical complications requiring hospitalization, and having jejunoileal bypass. Most risk factors were associated with the polyneuropathy group. Sural nerve biopsies showed prominent axonal degeneration and perivascular inflammation.

CONCLUSIONS

Peripheral neuropathy (PN) occurs more frequently after bariatric surgery (BS) than after another abdominal surgery. The three clinical patterns of PN after BS are sensory-predominant polyneuropathy, mononeuropathy, and radiculoplexus neuropathy. Malnutrition may be the most important risk factor, and patients should attend nutritional clinics. Inflammation and altered immunity may play a role in the pathogenesis, but further study is needed.

Use of oxcarbazepine to treat a pediatric patient with resistant complex regional pain syndrome

We describe a 12-year-old patient with severe, protracted complex regional pain syndrome type I. His pain did not respond to gabapentin, amitriptyline, physical therapy, opioids, or nonsteroidal drugs. Sympathetic or regional block was not attempted because of persistent bacteremia and severe local sepsis. His pain responded dramatically to the addition of oxcarbazepine, with rapid improvement in his symptoms and functional status. We suggest that oxcarbazepine might be a useful adjunct in the treatment of gabapentin-resistant complex regional pain syndrome type I in children and should be considered.

PERSPECTIVE

Oxcarbazepine's antinociceptive effect is mediated via sodium channel inhibition in neuropathic models and by inhibition of substance P and prostaglandins in anti-inflammatory models. The efficacy of oxcarbazepine in this patient might be attributable to these mechanisms or possibly to synergism with either gabapentin or the anti-inflammatory effects produced by amitriptyline.

Ulnar collateral ligament of the elbow

Recent advances in the diagnosis and treatment of the overhead athlete's elbow has led the medical community to understand that the ulnar collateral ligament (UCL) of the elbow is more commonly injured than originally thought. Injury can result in secondary symptoms and problems in other regions of the elbow. Sports requiring an overhead motion, such as throwing a ball, hitting a ball overhead, or serving a tennis ball, imparts a valgus stress on the elbow that is resisted by the UCL. Throwing sidearm or hitting a forehand in tennis, squash, or racquetball may also impart a valgus stress to the elbow. Repeated or excessive valgus stress places a force on the UCL that may result in injury to the ligament. Injury to the UCL may result in problems in other areas of the elbow, including the ulnar nerve, the flexor-pronator musculotendinous unit, the radiocapitellar joint and the posterior compartment of the elbow, in addition to being a cause of loose bodies within the elbow. This article reviews the anatomy, biomechanics, and pathophysiology of injury to the UCL and injuries to the other structures that result from UCL injury. Also reviewed are patient history, examination techniques, tests that help confirm the diagnosis of UCL injury, and treatment of the injured UCL.

Multifocal motor neuropathy: current concepts and controversies

Multifocal motor neuropathy (MMN) is now a well-defined purely motor multineuropathy characterized by the presence of multifocal partial motor conduction blocks (CB), frequent association with anti-GM1 IgM antibodies, and usually a good response to high-dose intravenous immunoglobulin (IVIg) therapy. However, several issues remain to be clarified in the diagnosis, pathogenesis, and therapy of this condition including its nosological position and its relation to other chronic dysimmune neuropathies; the degree of CB necessary for the diagnosis of MMN; the existence of an axonal form of MMN; the pathophysiological basis of CB; the pathogenetic role of antiganglioside antibodies; the mechanism of action of IVIg treatments in MMN and the most effective regimen; and the treatment to be used in unresponsive patients. These issues are addressed in this review of the main clinical, electrophysiological, immunological, and therapeutic features of this neuropathy.

Schwann cell overexpression of the GPR7 receptor in inflammatory and painful neuropathies

The human 7-transmembrane receptor GPR7 has sequence similarity to opioid and somatostatin receptors, and can be activated by the recently discovered neuropeptides NPB and NPW. This receptor is highly expressed in the nervous system, with suggested roles in neuroendocrine events and pain signaling. In this study, we investigated whether the GPR7 receptor is expressed in the peripheral nervous system under normal and pathological conditions. A low level of GPR7 receptor was observed in myelin-forming Schwann cells in both normal human and rat nerve, and in primary rat Schwann cell cultures. Peripheral nerve samples taken from patients exhibiting inflammatory/immune-mediated neuropathies showed a dramatic increase of GPR7 receptor expression restricted to myelin-forming Schwann cells. Complementary animal models of immune-inflammatory and ligation-induced nerve injury and neuropathic pain similarly exhibited an increased myelin-associated expression of GPR7 receptor. These results suggest a relationship between the pathogenesis of inflammatory/immune-mediated neuropathies, GPR7 receptor expression, and pain transmission.

ATP binding cassette transporter ABC1 is required for the release of interleukin-1beta by P2X7-stimulated and lipopolysaccharide-primed mouse Schwann cells

Schwann cells are best known as myelinating glial cells of the peripheral nervous system, but they also participate actively in the sphere of immunity by producing pro-inflammatory cytokines, such as interleukin-1beta (IL-1beta). In a previous study, we demonstrated that posttranslational processing of IL-1beta by immune-challenged Schwann cells required the P2X7 receptor. Remarkably, the release of IL-1beta was not associated with cell death, indicating the involvement of an active mechanism. ATP binding cassette (ABC) transporters are known to transport leaderless secretory proteins, such as IL-1beta; therefore, we investigated whether such transporters were at work in Schwann cells. Mouse Schwann cells expressed ABC1 transporter mRNA and displayed the functional protein. Glybenclamide and diisothiocyanato-stilbene-disulfonic acid (DIDS), two blockers of chloride fluxes that drive the export activity of ABC1 transporters, inhibited IL-1beta release without altering its intracellular processing. Enhancing chloride efflux potentiated the release of IL-1beta, while decreasing it led to a strong reduction in its release. Because the stimulation of the P2X7 receptor also activates a chloride conductance, we investigated the possibility of a sole anionic pathway mobilized by the P2X7 receptor and ABC1. Glybenclamide and DIDS had no significant effects on the P2X7-activated chloride current suggesting therefore the existence of two different pathways. In summary, ABC1 transporters are required for the release of IL-1beta by mouse Schwann cells. Being associated together with chloride conductance, P2X7 receptors and ABC1 transporters delineate a subtle and complex regulation of IL-1beta production in mammalian Schwann cells. Furthermore, ABC1 transporters could be a target of therapeutic interest for regulating IL-1beta activity in neuroinflammation disorders.

Characterization of a cyclooxygenase-2-765G???C promoter polymorphism in human neural cells

Direct sequencing of the human cyclooxygenase-2 gene promoter revealed a common single nucleotide substitution, cyclooxygenase-2-765G-->C, in 24.5% of the populations analyzed. This change introduced a 20 base pair polypyrimidine/polypurine element and a partial recognition feature for RXRalpha, the 9-cis retinoic acid receptor, into the polymorphic promoter. Cyclooxygenase-2-765G-->C constructs, when transfected into human neural cells, exhibited a 1.4-fold higher level of basal expression, while the proinflammatory factors interleukin-1beta and 9-cis retinoic acid synergistically induced polymorphic promoter activity 2.4-fold over wild type. These results suggest that under specific conditions of cellular stress, a common variation in cyclooxygenase-2 promoter structure may enhance cyclooxygenase-2 transcription, and this may contribute to the proliferation of an inflammatory response in brain cells.

A study of leprosy reactions in a tertiary hospital in Delhi

A retrospective study of 531 leprosy patients was undertaken to study the profile of reactions in the post Multi-Drug-Therapy period in a tertiary hospital in Delhi. BT was the most common group. The prevalence of reactions was found to be 8.09% for the Type 1 and 4.70% for the Type 2 reactions for a male:female ratio of 2.2. The Type 1 reaction was most frequently observed in the BB group followed by BL, BT and LL groups respectively. More than half of the patients had reactions at the time of presentation. In only 39.8% of the patients did reaction follow Multi-Drug-Therapy. In 4.5% of the patients with Type 1 reactions (T1R), concomitant infections were noted. The most common presentation of T1R was cutaneous lesions (74.41%) followed by cutaneous lesions and neuritis (53.6%), neuritis alone (12.1%), and only edema of hands and feet (7.31%) respectively. The Type 2 reactions (T2R) presented chiefly as papulo-nodular (92%) lesions followed by pustulonecrotic (8%) lesions. Associated neuritis was found in 40% and periosteitis and iritis in 8% and 4%, respectively. In 8.6% of the patients with T2R, precipitating factors could be observed. The prevalence of deformities in patients with reaction was 25%, and was more common in females. Deformities were observed in 23.25% of the T1R patients and 28% of the T2R patients.

Peripheral neuropathy in hepatitis-related mixed cryoglobulinemia: electrophysiologic follow-up study

A retrospective study was performed on 27 patients with hepatitis C (HCV)-related mixed cryoglobulinemia (purpura, arthralgia, hepatitis, glomerulonephritis, peripheral neuropathy) to assess peripheral nerve involvement during follow-up of up to 8 years. All patients had the same degree of organ/system involvement initially and were clinically evaluated at least annually. All 27 patients received steroids; 15 also received recombinant interferon-alpha 2b (rIFN-alpha 2b). At first examination, neurological signs and electrodiagnostic findings consistent with peripheral neuropathy were found in 20 (74%) and in 24 (88.8%) patients, respectively. Neurological evaluation and electrodiagnostic data at 3 and 8 years revealed worsening of neuropathy, whereas the other manifestations of mixed cryoglobulinemia (MC) were stable. At the last examination, clinical and electrodiagnostic signs of neuropathy were found in 25 patients (92.5%), occurring in 1 of 3 patients with normal initial findings, and worsened in 8. A more severe neuropathy was observed in 3 (25%) of the patients treated with prednisone alone and in 6 (40%) of the patients additionally treated with rIFN-alpha 2b. Our data confirm that in patients with HCV-related MC, peripheral nerve involvement is frequent, is progressive, and does not seem to benefit by addition of rIFN-alpha 2b to steroid treatment.

Anti-allodynic and anti-hyperalgesic effects of nociceptin receptor antagonist, JTC-801, in rats after spinal nerve injury and inflammation

The effects of nociceptin/orphanin FQ (N/OFQ) peptide receptor antagonist JTC-801 on allodynia and hyperalgesia were examined in rats in order to explore the involvement of N/OFQ system in these pathological pain states. Tactile allodynia induced by L5/L6 spinal nerve ligation was reversed by both systemic (3-30 mg/kg) and spinal (22.5 and 45 pg) JTC-801 in a dose-dependent manner. Concerning hyperalgesia induced by formalin injection into the hindpaw, JTC-801 dose-dependently suppressed the second phase, but not the first phase, of the licking behavior. Furthermore, systemic JTC-801 reduced Fos-like immunoreactivity in the dorsal horn of the spinal cord (laminae I/II). In conclusion, N/OFQ receptor antagonist JTC-801 exerted anti-allodynic and anti-hyperalgesic effects in rats, suggesting that N/OFQ system might be involved in the modulation of neuropathic pain and inflammatory hyperalgesia.

The pathogenesis of multiple sclerosis: is it really a primary inflammatory process?

The pathogenesis of multiple sclerosis (MS) remains unknown. Although inflammation, demyelination and axonal injury are all involved, the primary pathogenic process is not clear. In this paper we challenge the hypothesis that MS is a primary inflammatory condition, and suggest that axonal damage may occur independently.

CD44 overexpression by oligodendrocytes: a novel mouse model of inflammation-independent demyelination and dysmyelination

The CD44 transmembrane glycoprotein family has been implicated in cell-cell adhesion and cell signaling in response to components of the extracellular matrix but its role in the nervous system is not understood. CD44 proteins are elevated in Schwann cells and oligodendrocytes following nervous system insults, in inflammatory demyelinating lesions, and in tumors. Here, we tested the hypothesis that elevated CD44 expression influences Schwann cell and oligodendrocyte functions by generating transgenic mice that express CD44 under the control of the 2',3'-cyclic nucleotide-3'-phosphodiesterase (CNPase) promoter. These mice failed to develop peripheral nerve or CNS tumors. However, they did develop severe tremors that were associated with CNS dysmyelination and progressive demyelination. Loss of CNS myelin was not due to alterations in early oligodendrocyte precursor differentiation, proliferation, or survival. Myelination in the PNS appeared normal. In no instance was there any evidence of an inflammatory response that could account for the loss of CNS myelin. These findings suggest that CNPase-CD44 mice are a novel model for noninflammatory progressive demyelinating disease and support a potential role for CD44 proteins expressed by glial cells in promoting demyelination.

Experimental malignancy in the rat induces early hypersensitivity indicative of neuritis

Cancer pain mechanisms involve multiple factors including the accompanying inflammatory process neural effects. Inflammation along a nerve trunk (neuritis) has been shown to induce hypersensitivity at the innervated target organ. In this experiment the neural effects of MAT B mammary adenocarcinoma cells implanted adjacent to sciatic nerve (MAT group) were compared to those induced by thymus cell extract (THY), saline (SAL) and the potent proinflammatory agent Complete Freund's adjuvant (CFA). Significant pain behavior was detected only in the ipsilateral hindpaw of MAT and CFA rats lasting seven days post-operatively (dpo). On the ninth dpo MAT rats developed significant hyposensitivity to mechanical and electrical stimuli. Interleukin (IL)-6 levels (ELISA) from MAT and CFA exposed nerves were significantly elevated at dpo 2 and remained so in MAT at dpo 8. Indomethacin (1 mg/kg i.p.) abolished the observed pain responses in MAT and CFA rats exposed nerves. Light microscopy of the MAT nerves at the second dpo revealed neural infiltration of immune and malignant cells with mild edema. By the seventh dpo there was nerve damage and at dpo 14 nerve tissue was largely replaced by malignant and immune cells. Electrophysiology of saphenous nerves exposed to MAT, CFA or SAL revealed significantly increased spontaneous activity in MAT and CFA groups. Spike response to hindpaw mechanical stimulation was significantly reduced only in the MAT group (dpo 6-9) suggestive of nerve damage. Inflammatory neuritis is an early expression of malignancy and may play a role in chronic cancer-related pain initiation and additionally may offer diagnostic opportunities.

Proteinase-activated receptors in the nervous system

Recent data point to important roles for proteinases and their cognate proteinase-activated receptors (PARs) in the ontogeny and pathophysiology of the nervous system. PARs are a family of G-protein-coupled receptors that can affect neural cell proliferation, morphology and physiology. PARs also have important roles in neuroinflammatory and degenerative diseases such as human immunodeficiency virus-associated dementia, Alzheimer's disease and pain. These receptors might also influence the pathogenesis of stroke and multiple sclerosis, conditions in which the blood-brain barrier is disrupted. The diversity of effects of PARs on neural function and their widespread distribution in the nervous system make them attractive therapeutic targets for neurological disorders. Here, we review the roles of PARs in the central and peripheral nervous systems during health and disease, with a focus on neuroinflammatory and degenerative disorders.

Effect of dexamethasone and dipyrone on lingual and inferior alveolar nerve hypersensitivity following third molar extractions: preliminary report

AIMS

To study the effect of dexamethazone and dipyrone on sensory changes in the innervation territories of the inferior alveolar, infraorbital, and lingual nerves caused by third molar extractions.

METHODS

Fourteen patients (8 men and 6 women) were divided randomly into 2 groups. The first group received dipyrone preoperatively, while the second group received dipyrone and dexamethazone preoperatively. All patients in the study received a prophylactic preoperative dose of amoxicillin (500 mg) as well as dipyrone postoperatively. In all patients, a single mandibular third molar was removed, while in 2 patients the contralateral third molar was removed at a subsequent time. Electrical detection thresholds were assessed in the inferior alveolar, lingual, and infraorbital nerve regions prior to surgery and 2 and 8 days following surgery. The level of perioperative pain, difficulty of extraction, and distance of molar root apices from the inferior alveolar nerve canal were also assessed.

RESULTS

Patients who received only dipyrone had significantly reduced lingual and inferior alveolar nerve electrical detection thresholds 2 days after surgery, which returned to nearly baseline values by the eighth day postoperatively. In patients who received dexamethasone, no significant reduction in the electrical detection threshold was found.

CONCLUSION

Preoperative treatment with dexamethasone and dipyrone but not dipyrone alone prevents sensory hypersensitivity following third molar extraction.

Peripheral norepinephrine exacerbates neuritis-induced hyperalgesia

Inflammation of a peripheral nerve (neuritis) causes mechanical and thermal hyperalgesia in the region in which the inflamed nerve innervates. We investigated whether peripherally applied norepinephrine (NE) would exacerbate mechanical hyperalgesia in rats with neuritis. After inflammation of the left L5 spinal nerve with complete Freund's adjuvant, the foot withdrawal thresholds to mechanical stimuli applied to the affected hind paw (mechanical thresholds) were decreased significantly, indicating the development of mechanical hyperalgesia. An intradermal injection of NE to the affected paw further aggravated mechanical hyperalgesia transiently (1-3 days) and then recovered to the pre-NE injection levels afterwards. This responsiveness to NE (adrenergic sensitivity) was observed not only while rats were showing inflammatory hyperalgesia but also after recovering from it. The effect of NE on mechanical hyperalgesia was mediated by both peripheral alpha(1)- and alpha(2)-adrenoceptors. Immunohistochemical study of the previously inflamed nerve showed that proinflammatory cytokine tumor necrosis factor immunoreactivity was significantly higher in the rats showing adrenergic sensitivity compared to rats without adrenergic sensitivity. The data thus suggest that peripheral NE, when released in an excessive amount from the sympathetic nervous system, might play an important role in the aggravation of pain in neuritis.

[Characteristics of motor activity disorders in patients with vertebrogenic lumbosacral pain syndrome]

The study is based on clinical examination of movement disorder in 126 patients (men--103, women--23) with lumbosacral pain syndrome. The authors revealed how statico-dynamic and neurotic disorders had been formed depending on structural peculiarities of primary pathologic process and thus determining different clinical forms. Mechanisms of syndromologic manifestation of suffering in every case were substantiated; own approaches to anatomico-topical diagnostics and objectification of pathology course in dynamic were suggested.

Effects of GCP-II inhibition on responses of dorsal horn neurones after inflammation and neuropathy: an electrophysiological study in the rat

N-Acetylaspartylglutamate (NAAG) is a peptide neurotransmitter present in the brain and spinal cord. It is hydrolysed by glutamate carboxypeptidase II (GCPII); thus, the GCP-II inhibitor 2-[phosphono-methyl]-pentanedioic acid (2-PMPA) protects endogenous NAAG from degradation, allowing its effects to be studied in vivo. We recorded the effect of spinal 2-PMPA (50-1000 microg) on the electrical-evoked activity of dorsal horn neurones in normal and carrageenan-inflamed animals, and in the spinal nerve ligation (SNL) model of neuropathy and sham-operated animals. In normal animals, 1000 microg 2-PMPA selectively inhibited noxious-evoked activity (input, post-discharge and C- and Adelta-fibre-evoked responses), and not low threshold Abeta-fibre-evoked responses. After carrageenan inflammation, the lower dose of 100 microg 2-PMPA inhibited input, post-discharge, C- and Adelta-fibre-evoked responses by a significantly greater amount than the same dose in normal animals. 2-PMPA inhibited neuronal responses less consistently in sham-operated and SNL animals, and effects were not significantly different from those seen in normal animals. NAAG is an agonist at the inhibitory metabotropic glutamate receptor mGluR3, and 2-PMPA may inhibit nociceptive transmission in normal animals by elevating synaptic NAAG levels, allowing it to activate mGluR3 and thus reducing transmitter release from afferent nerve terminals. mGluR3 expression in the superficial dorsal horn is upregulated after peripheral inflammation, perhaps explaining the greater inhibition of neuronal responses we observed after carrageenan inflammation. These results support an important role of endogenous NAAG in the spinal processing of noxious information.

Expression of neurotrophic factors in the dorsal root ganglion in a rat model of lumbar disc herniation

A variety of molecules released by inflammatory reactions in the dorsal root and dorsal root ganglion (DRG) may play important roles in the pathology of neuronal abnormalities in lumbar disc herniation. In order to elucidate the pathophysiological mechanisms of painful radiculopathy, secondary to lumbar disc herniation, we evaluated pain-related behavior and the change of nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF) expression in the DRG and dorsal root using a rat model of lumbar disc herniation. In the nucleus pulposus (NP) group, the left L4/5 nerve roots were exposed after hemilaminectomies and autologous intervertebral discs, which were obtained from coccygeal intervertebral discs, were implanted on each of the exposed nerve roots without mechanical compression. Rats in the NP group, but not the sham-operated rats, developed mechanical allodynia on the ipsilateral hind paw for 1 day after surgery and showed a significant increase in the number of NGF-immunoreactive (IR) cells in the nerve root and DRG. NGF-IR cells in the nerve root and DRG included macrophages and Schwann cells, because these cells were labeled for NGF and ED-1 or glial fibrillary acid protein by dual immunostaining. A significant increase in the percentage of BDNF-IR neurons in the DRG was observed in the NP group at 3 days after surgery and the increase in BDNF mRNA expression was confirmed using in situ hybridization histochemistry and reverse transcription-polymerase chain reaction. We also injected NGF into the endoneurial space of the normal rat spinal nerve root and found that the NGF injection produced dose-dependent mechanical allodynia on the ipsilateral hind paw at 1 day after surgery and an increase in the percentage of BDNF-IR neurons in the DRG at 3 days after surgery compared to the group receiving saline injection. These findings suggest that in the lumbar disc herniation model, i.e. neuritis of the nerve root, increased NGF produced by the inflammatory responses in the dorsal root and DRG tissues may affect the production of BDNF in the DRG and may play important roles in the modulation of the dorsal horn neurons. These changes in neurotrophic factors in the primary afferents may be involved in the pathophysiological mechanisms of neuropathic pain produced by lumbar disc herniation.

[Rehabilitation of the vertigo patient]

Vestibular exercises are getting an increasing place in the different way to treat vertigo. Vestibular training can be an interesting alternative to drugs medication. We will limit this presentation to the principal peripheral vestibulopathy as benign paroxysmal positioning vertigo, vestibular neuritis and the dizziness of elderly.

Large myelinated nerve fiber hypersensitivity in oral malignancy

OBJECTIVES

The purpose of this study was to assess the sensory function of trigeminal nerve A-beta fibers in suspected soft tissue oral malignancies.

STUDY DESIGN

Twenty-three patients referred for the evaluation of an oral lesion suspected of malignancy were included in the study. All lesions were classified as in, near, or out of the nerve territory containing the lesion. Within these subgroups we assessed the sensitivity of A-beta primary afferents to weak electrical currents applied bilaterally to regions innervated by 3 peripheral branches of the trigeminal nerve. The ratio of electrical detection thresholds from the affected and the unaffected side was calculated. Electrical detection threshold ratios were contrasted with the results of physical examination, radiographic imaging, and biopsy.

RESULTS

For dermatomes containing the lesions, ratios were lower than 0.8 in 12 patients. Biopsy showed that the lesions in 10 of these 12 patients were malignant. No malignancy was found in the remaining 11 patients.

CONCLUSIONS

A-beta primary afferent hypersensitivity is observed to occur in nerves exposed to soft tissue oral malignancy.