Alcoholic neuropathy is clinicopathologically distinct from thiamine-deficiency neuropathy

Alcoholic neuropathy: possible mechanisms and future treatment possibilities

Chronic alcohol consumption produces painful peripheral neuropathy for which there is no reliable successful therapy, mainly due to lack of understanding of its pathobiology. Alcoholic neuropathy involves coasting caused by damage to nerves that results from long term excessive drinking of alcohol and is characterized by spontaneous burning pain, hyperalgesia and allodynia. The mechanism behind alcoholic neuropathy is not well understood, but several explanations have been proposed. These include activation of spinal cord microglia after chronic alcohol consumption, oxidative stress leading to free radical damage to nerves, activation of mGlu5 receptors in the spinal cord and activation of the sympathoadrenal and hypothalamo-pituitary-adrenal (HPA) axis. Nutritional deficiency (especially thiamine deficiency) and/or the direct toxic effect of alcohol or both have also been implicated in alcohol-induced neuropathic pain. Treatment is directed towards halting further damage to the peripheral nerves and restoring their normal functioning. This can be achieved by alcohol abstinence and a nutritionally balanced diet supplemented by all B vitamins. However, in the setting of ongoing alcohol use, vitamin supplementation alone has not been convincingly shown to be sufficient for improvement in most patients. The present review is focused around the multiple pathways involved in the development of peripheral neuropathy associated with chronic alcohol intake and the different therapeutic agents which may find a place in the therapeutic armamentarium for both prevention and management of alcoholic neuropathy.

Subclinical peripheral neuropathy is a common finding in colorectal cancer patients prior to chemotherapy

PURPOSE

Of the numerous complications associated with cancer and cancer treatment, peripheral neuropathy is a deleterious and persistent patient complaint commonly attributed to chemotherapy. The present study investigated the occurrence of subclinical peripheral neuropathy in patients with colorectal cancer before the initiation of chemotherapy.

EXPERIMENTAL DESIGN

Fifty-two patients underwent extensive quantitative sensory testing (QST) before receiving chemotherapy. Changes in multiple functions of primary afferent fibers were assessed and compared with a group of healthy control subjects. Skin temperature, sensorimotor function, sharpness detection, and thermal detection were measured, as was touch detection, using both conventional (von Frey monofilaments) and novel (Bumps detection test) methodology.

RESULTS

Patients had subclinical deficits, especially in sensorimotor function, detection of thermal stimuli, and touch detection that were present before the initiation of chemotherapy. The measured impairment in touch sensation was especially pronounced when using the Bumps detection test.

CONCLUSIONS

The patients with colorectal cancer in this study exhibited deficits in sensory function before undergoing chemotherapy treatment, implicating the disease itself as a contributing factor in chemotherapy-induced peripheral neuropathy. The widespread nature of the observed deficits further indicated that cancer is affecting multiple primary afferent subtypes. Specific to the finding of impaired touch sensation, results from this study highlight the use of newly used methodology, the Bumps detection test, as a sensitive and useful tool in the early detection of peripheral neuropathy.

Processing of nerve biopsies: a practical guide for neuropathologists

Nerve biopsy is a valuable tool in the diagnostic work-up of peripheral neuropathies. Currently, major indications include interstitial pathologies such as suspected vasculitis and amyloidosis, atypical cases of inflammatory neuropathy and the differential diagnosis of hereditary neuropathies that cannot be specified otherwise. However, surgical removal of a piece of nerve causes a sensory deficit and – in some cases – chronic pain. Therefore, a nerve biopsy is usually performed only when other clinical, laboratory and electrophysiological methods have failed to clarify the cause of disease. The neuropathological work-up should include at least paraffin and resin semithin histology using a panel of conventional and immunohistochemical stains. Cryostat section staining, teased fiber preparations, electron microscopy and molecular genetic analyses are potentially useful additional methods in a subset of cases. Being performed, processed and read by experienced physicians and technicians nerve biopsies can provide important information relevant for clinical management.

The spectrum of clinicopathological features in pure autonomic neuropathy

We assessed the clinicopathological features of nine patients with pure autonomic neuropathy, that is, neuropathy without sensory or motor deficits. The duration from symptom onset to diagnosis ranged from 1 month to 13 years. Of eight patients in whom serum antiganglionic acetylcholine receptor antibody was determined, four were positive. All patients who tested positive for this antibody manifested widespread autonomic dysfunction, with the exception of one patient who only experienced orthostatic hypotension. However, patients who were negative for the antiganglionic acetylcholine receptor antibody presented with partial autonomic failure. One of these patients had diffuse parasympathetic failure and generalized hypohidrosis but no orthostatic hypotension, which is clinically compatible with postganglionic cholinergic dysautonomia. Electron microscopic examination revealed a variable degree of reduction in unmyelinated fibers. Compared with normal controls, the patients had a significantly increased density of collagen pockets (p < 0.05). Additionally, the percentage of Schwann cell subunits with axons (out of the total number of Schwann cell subunits associated with unmyelinated fibers) was significantly decreased (p < 0.01). The density of unmyelinated fibers tended to decrease with increasing time between the onset of autonomic symptoms and biopsy (p < 0.05). In conclusion, the clinical and pathological features of pure autonomic neuropathy vary in terms of progression, autonomic involvement, presence of the antiganglionic acetylcholine receptor antibody, and loss of unmyelinated fibers.

Muscle pain in models of chemotherapy-induced and alcohol-induced peripheral neuropathy

OBJECTIVE

While inflammatory pain is well described in skeletal muscle, neuropathic muscle pain remains to be clarified. We used 3 well-established rodent models of peripheral neuropathy to evaluate for muscle pain.

METHODS

In rats exposed to either of 2 neurotoxic cancer chemotherapies, paclitaxel or oxaliplatin, or to alcohol consumption, we assessed the evolution of mechanical hyperalgesia in skeletal muscle and skin, in the same animal. To explore the involvement of protein kinase C epsilon (PKCε), a second messenger implicated in some forms of neuropathic pain, antisense oligodeoxynucleotides (AS-ODNs) or mismatch ODNs (MM-ODNs) for PKCε were administered intrathecally.

RESULTS

Rats submitted to models of chemotherapy-induced and alcohol-induced neuropathy developed persistent muscle hyperalgesia, which evolved in parallel in muscle and skin. The administration of PKCε AS, which has been shown to mediate cutaneous hyperalgesia in paclitaxel and ethanol models of neuropathic pain, also inhibited muscle hyperalgesia induced by these agents. Stopping AS-ODN was associated with the reappearance of hyperalgesia at both sites. The AS-ODN to PKCε treatment was devoid of effect in both muscle and skin in the oxaliplatin neuropathy model.

INTERPRETATION

Our results support the suggestion that neuropathic muscle pain may be a greater clinical problem than generally appreciated.

The effect of phosphodiesterase-4-specific inhibitor in the rat model of spinal nerve ligation

OBJECTIVE

Peripheral neuropathy is characterized by hyperalgesia, spontaneous burning pain, and allodynia. The purpose of this study was to investigate the effect of rolipram, a phosphodiesterase-4-specific inhibitor, in a segmental spinal nerve ligation model in rats.

METHODS

Both the L5 and L6 spinal nerves of the left side of the rats were ligated. Phosphodiesterase-4 inhibitor (rolipram) and saline (vehicle) were administered intraperitoneally. We measured mechanical allodynia using von Frey filaments and a nerve conduction study.

RESULTS

The mechanical allodynia, which began to manifest on the first day, peaked within 2 days. Multiple intraperitoneal injections of rolipram ameliorated the mechanical allodynia. Furthermore, an intraperitoneal administration of rolipram improved the development of pain behavior and nerve conduction velocity.

CONCLUSION

This study suggests that the phosphodiesterase-4 inhibitor, rolipram, alleviates mechanical allodynia induced by segmental spinal nerve ligation in rats. This finding may have clinical implications.

Diagnosis of sporadic transthyretin Val30Met familial amyloid polyneuropathy: a practical analysis

Transthyretin (TTR) Val30Met-associated familial amyloid polyneuropathy (FAP ATTR Val30Met) is the most common form of FAP and is now prevalent in areas other than those seen within conventional endemic foci. We investigated 15 patients with FAP ATTR Val30Met without a family history of FAP who were referred for sural nerve biopsy. Initial symptoms included somatic neuropathy in all patients, while sensory dissociation and autonomic symptoms were apparent only in two and seven patients, respectively. Nonspecific neuropathic features and slight abnormalities in cerebrospinal fluid protein levels and in electrophysiological indices related to nerve conduction led clinicians to initially suspect chronic inflammatory demyelinating polyneuropathy (CIDP) in some patients. Small-fiber predominant loss was observed in a minority of patients. In terms of cardiac involvement, findings suggestive of subclinical cardiomyopathy due to amyloid deposition, such as cardiomegaly on chest X-ray, thickening of the interventricular septum, and granular sparkling echo on echocardiography, were seen alone or in combination in 11 of 14 examined patients. In conclusion, clinicians should consider the possibility of FAP ATTR Val30Met in patients presenting with neuropathy of undetermined etiology to avoid misdiagnosis. Detecting subclinical cardiac involvement may help to diagnose late-onset FAP ATTR Val30Met in those without a family history of the disease.

Alcohol-related peripheral neuropathy: nutritional, toxic, or both?

Alcohol-related peripheral neuropathy (ALN) is a potentially debilitating complication of alcoholism that results in sensory, motor, and autonomic dysfunction. Unfortunately, ALN is rarely discussed as a specific disease entity in textbooks because it is widely assumed to primarily reflect consequences of nutritional deficiency. This hypothesis is largely based on observations first made over eight decades ago when it was demonstrated that thiamine deficiency (beriberi) neuropathy was clinically similar to ALN. In recent studies, failure of thiamine treatment to reverse ALN, together with new information demonstrating clinical and electrophysiological distinctions between ALN and nutritional deficiency neuropathies, suggests that alcohol itself may significantly predispose and enhance development of neuropathy in the appropriate clinical setting. We reviewed the evidence on both sides and conclude that ALN should be regarded as a toxic rather than nutritional neuropathy.

Clinicopathological features of acute autonomic and sensory neuropathy

Acute autonomic and sensory neuropathy is a rare disorder that has been only anecdotally reported. We characterized the clinical, electrophysiological, pathological and prognostic features of 21 patients with acute autonomic and sensory neuropathy. An antecedent event, mostly an upper respiratory tract or gastrointestinal tract infection, was reported in two-thirds of patients. Profound autonomic failure with various degrees of sensory impairment characterized the neuropathic features in all patients. The initial symptoms were those related to autonomic disturbance or superficial sensory impairment in all patients, while deep sensory impairment accompanied by sensory ataxia subsequently appeared in 12 patients. The severity of sensory ataxia tended to become worse as the duration from the onset to the peak phase of neuropathy became longer (P<0.001). The distribution of sensory manifestations included the proximal regions of the limbs, face, scalp and trunk in most patients. It tended to be asymmetrical and segmental, rather than presenting as a symmetric polyneuropathy. Pain of the involved region was a common and serious symptom. In addition to autonomic and sensory symptoms, coughing episodes, psychiatric symptoms, sleep apnoea and aspiration, pneumonia made it difficult to manage the clinical condition. Nerve conduction studies revealed the reduction of sensory nerve action potentials in patients with sensory ataxia, while it was relatively preserved in patients without sensory ataxia. Magnetic resonance imaging of the spinal cord revealed a high-intensity area in the posterior column on T(2)*-weighted gradient echo image in patients with sensory ataxia but not in those without it. Sural nerve biopsy revealed small-fibre predominant axonal loss without evidence of nerve regeneration. In an autopsy case with impairment of both superficial and deep sensations, we observed severe neuronal cell loss in the thoracic sympathetic and dorsal root ganglia, and Auerbach's plexus with well preserved anterior hone cells. Myelinated fibres in the anterior spinal root were preserved, while those in the posterior spinal root and the posterior column of the spinal cord were depleted. Although recovery of sensory impairment was poor, autonomic dysfunction was ameliorated to some degree within several months in most patients. In conclusion, an immune-mediated mechanism may be associated with acute autonomic and sensory neuropathy. Small neuronal cells in the autonomic and sensory ganglia may be affected in the initial phase, and subsequently, large neuronal cells in the sensory ganglia are damaged.

Ethanol and cognition: indirect effects, neurotoxicity and neuroprotection: a review

Ethanol affects cognition in a number of ways. Indirect effects include intoxication, withdrawal, brain trauma, central nervous system infection, hypoglycemia, hepatic failure, and Marchiafava-Bignami disease. Nutritional deficiency can cause pellagra and Wernicke-Korsakoff disorder. Additionally, ethanol is a direct neurotoxin and in sufficient dosage can cause lasting dementia. However, ethanol also has neuroprotectant properties and in low-to-moderate dosage reduces the risk of dementia, including Alzheimer type. In fetuses ethanol is teratogenic, and whether there exists a safe dose during pregnancy is uncertain and controversial.

Neurologic presentations of nutritional deficiencies

Optimal functioning of the central and peripheral nervous system is dependent on a constant supply of appropriate nutrients. The first section of this review discusses neurologic manifestations related to deficiency of key nutrients such as vitamin B(12), folate, copper, vitamin E, thiamine, and others. The second section addresses neurologic complications related to bariatric surgery. The third sections includes neurologic presentations caused by nutrient deficiencies in the setting of alcoholism. The concluding section addresses neurologic deficiency diseases that have a geographic predilection.

Not all neuropathy in diabetes is of diabetic etiology: differential diagnosis of diabetic neuropathy

Diabetic peripheral neuropathy is the most common peripheral neuropathy in the developed world; however, not all patients with diabetes and peripheral nerve disease have a peripheral neuropathy caused by diabetes. Several (although not all) studies have drawn attention to the presence of other potential causes of a neuropathy in individuals with diabetes; 10% to 50% of individuals with diabetes may have an additional potential cause of a peripheral neuropathy and some may have more than one cause. Neurotoxic medications, alcohol abuse, vitamin B(12) deficiency, renal disease, chronic inflammatory demyelinating neuropathy, inherited neuropathy, and vasculitis are the most common additional potential causes of a peripheral neuropathy in these series. The most common disorders in the differential diagnosis of a generalized diabetic peripheral neuropathy are discussed in this article. Prospective studies to investigate the prevalence of other disorders that might be responsible for a peripheral neuropathy in individuals with diabetes are warranted.

Tocotrienol ameliorates behavioral and biochemical alterations in the rat model of alcoholic neuropathy

Chronic alcohol consumption produces a painful peripheral neuropathy for which there is no reliable successful therapy, which is mainly due to lack of understanding of its pathobiology. Alcoholic neuropathy is characterized by spontaneous burning pain, hyperalgesia (an exaggerated pain in response to painful stimuli) and allodynia (a pain evoked by normally innocuous stimuli). Chronic alcohol intake is known to decrease the nociceptive threshold with increased oxidative-nitrosative stress and release of proinflammatory cytokines coupled with activation of protein kinase C. The aim of the present study is to investigate the effect of both isoforms of vitamin E, alpha-tocopherol (100mg/kg; oral gavage) and tocotrienol (50, 100 and 200mg/kg; oral gavage) against alcohol-induced neuropathic pain in rats. Male Wistar rats, were administered 35% v/v ethanol (10 g/kg; oral gavage) for 10 weeks, and were treated with alpha-tocopherol and tocotrienol for the same duration. Ethanol-treated animals showed a significant decrease in nociceptive threshold as evident from decreased tail flick latency (thermal hyperalgesia) and decreased paw-withdrawal threshold in Randall-Sellito test (mechanical hyperalgesia) and von-Frey hair test (mechanical allodynia) along with the reduction in nerve glutathione and superoxide dismutase levels. TNF-alpha and IL-1beta levels were also significantly increased in both serum and sciatic nerve of ethanol-treated rats. Treatment with alpha-tocopherol and tocotrienol for 10 weeks significantly improved all the above-stated functional and biochemical deficits in a dose-dependent manner with more potent effects observed with tocotrienol. The study demonstrates the effectiveness of tocotrienol in attenuation of alcoholic neuropathy.

Severe anasarca due to beriberi heart disease and diabetic nephropathy

A 40-year-old man was transferred to our hospital because of severe anasarca. He was a heavy drinker for more than 20 years, and diagnosed with diabetes mellitus 8 years earlier and treated with retinal photocoagulation 8 months earlier. He reported loss of appetite after divorce 10 months prior to admission. On admission, he presented with systemic edema and dyspnea. Chest radiography showed massive pleural effusion and cardiomegaly. Serum total protein was 5.6 g/dl, albumin 2.6 g/dl, and urinary protein excretion was 5.3 g/day. Glucose tolerance test showed normal pattern. Ultrafiltration and continuous hemofiltration resulted in loss of 40 kg body weight in 5 days. Echocardiography revealed high-output heart failure and blood tests showed low serum thiamine level of 12 ng/ml (normal, >28 ng/ml). Accordingly, the diagnosis was established as beriberi heart disease complicated with nephrotic syndrome. Treatment with 50 mg/day thiamine intravenously and 80 mg/day furosemide resulted in increase in urine output, decrease in cardiac output, resolution of pulmonary effusion, and about 70 kg body weight loss. Percutaneous renal biopsy showed nodular glomerulosclerosis, mesangial matrix expansion, and thickening of glomerular basement membrane (GBM). Immunofluorescence study showed no glomerular deposition of immunoglobulin or complement. Electron microscopy showed GBM thickening and mesangial matrix deposition without electron-dense deposits or fibrils. These findings were compatible with diabetic glomerulosclerosis. In this patient, extreme malnutrition altered glucose tolerance but, on the other hand, nephrotic syndrome associated with diabetic nephropathy made the diagnosis of beriberi heart disease difficult.

Biopsy of the posterior interosseous nerve: a low morbidity method for assessment of peripheral nerve disorders

AIMS

The sural nerve is the commonest peripheral nerve biopsied to help in the diagnosis of peripheral neuropathy of unknown cause. However, associated complications limit its use. The aim was, as an alternative, to asses biopsy of the terminal branch of the posterior interosseous nerve (PIN) in the forearm.

METHODS

PIN pathology was morphometrically quantified in 10 male patients with Type 2 diabetes and compared with six PIN biopsy specimens taken post mortem from male cadavers with no history of neuropathy or trauma.

RESULTS

The PIN biopsy procedure provides a long (approximately 3 cm) mono- or bifascicular nerve biopsy with generous epineurial tissue and adjacent vessels. Our results show a significantly lower myelinated fibre density in subjects with diabetes [5782 (3332-9060)/mm(2)] compared with autopsy control material [9256 (6593-12,935)/mm(2), P < 0.007]. No postoperative discomfort or complications were encountered.

CONCLUSIONS

A reduction in myelinated fibre density has previously been shown to be a clinically meaningful measure of neuropathy in diabetic patients. We demonstrate similar findings using the PIN biopsy. The PIN biopsy procedure fulfils the criteria for nerve biopsy and was well tolerated by the patients. It may be a possible alternative to sural nerve biopsy to allow for diagnosis of neuropathy.

Rapidly developing weakness mimicking Guillain-Barré syndrome in beriberi neuropathy: two case reports

OBJECTIVE

We examined the diagnostic difficulty in thiamine deficiency.

METHODS

We report on two patients with polyneuropathy associated with thiamine deficiency (i.e., beriberi neuropathy) that presented with acute motor symptoms mimicking Guillain-Barré syndrome.

RESULTS

The cause of the thiamine deficiency was associated with gastrectomy to treat cancer in a 46-y-old man and with dietary imbalance in a 33-y-old man. The thiamine deficiency was not related to alcohol intake in either patient. In both patients, the upper and lower extremities showed a rapidly progressive weakness over the course of 1 mo. Muscle weakness in the first patient progressed even after admission to the hospital, and urinary retention, Wernicke's encephalopathy, lactic acidosis, paralytic ileus, and heart failure appeared subsequently. Clinical symptoms in both patients showed improvement after initiation of thiamine administration, although some residual deficit remained.

CONCLUSION

Thiamine deficiency must be actively considered as a possible cause of polyneuropathy, and variability in its clinical features should be taken into consideration.

Alcohol-induced stress in painful alcoholic neuropathy

Chronic alcohol consumption induces a painful small-fiber peripheral neuropathy, the severity of which increases during alcohol withdrawal. Chronic alcohol consumption also produces a sustained increase in stress hormones, epinephrine and corticosterone, that is exacerbated during alcohol withdrawal. We report that adrenal medullectomy and administration of a glucocorticoid receptor antagonist, mifepristone (RU 38486), both prevented and reversed a model of painful peripheral neuropathy in alcohol binge-drinking rats. Chronic administration of stress levels of epinephrine to rats that had undergone adrenal medullectomy and were being fed the alcohol diet reconstituted this phenotype. Intrathecal administration of oligodeoxynucleotides antisense to the beta(2)-adrenergic- or glucocorticoid-receptor also prevented and reversed the pro-nociceptive effects of ethanol. Our results suggest a convergence of the effects of mediators of the hypothalamic-pituitary- and sympathoadrenal-stress axes on sensory neurons in the induction and maintenance of alcohol-induced painful peripheral neuropathy.

Nonmyelinating Schwann cell involvement with well-preserved unmyelinated axons in Charcot-Marie-Tooth disease type 1A

Electron microscopic examination was performed to compare morphologic changes of nonmyelinating Schwann cells and unmyelinated axons in patients with Charcot-Marie-Tooth disease type 1A (CMT1A) with peripheral myelin protein 22 duplication (n = 27) and normal control individuals (n = 14). Complete transverse sural nerve cross-sections were obtained in 16 patients and the total number of axons and Schwann cells in each cross-section was estimated. In patients with CMT1A, the number of myelinated axons was significantly decreased, whereas unmyelinated axons were well-preserved and did not show any marked changes. The numbers of nuclei, subunits, and profiles of nonmyelinating Schwann cells were all increased significantly in patients with CMT1A, whereas the numbers of axons per unmyelinated axon-containing subunit were significantly decreased. Schwann cell subunits consisted of layers of flattened cytoplasmic profiles wrapped around unmyelinated axons in the patient with CMT1A. The numbers of nonmyelinating Schwann cell profiles were increased and the numbers of axons per unmyelinated axon-containing subunit were reduced even in young patients with well-preserved myelinated fibers. In conclusion, there is marked alteration of the population and morphology of nonmyelinating Schwann cells, and axon-Schwann cell interactions seem to be regulated differently between myelinated and unmyelinated fibers in CMT1A.

Interaction of thiamine deficiency and voluntary alcohol consumption disrupts rat corpus callosum ultrastructure

The relative roles of alcohol and thiamine deficiency in causing brain damage remain controversial in alcoholics without the Wernicke-Korsakoff syndrome. Experimental control over alcohol consumption and diet are impossible in humans but can be accomplished in animal models. This experiment was designed to differentiate the separate and combined effects on the macro- and ultrastructure of the corpus callosum of thiamine deficiency and voluntary alcohol consumption. Adult male alcohol-preferring (P) rats (9 chronically alcohol-exposed and 9 water controls) received a thiamine-deficient diet for 2 weeks. There were four groups: five rats previously exposed to alcohol were treated with pyrithiamine (a thiamine phosphorylation inhibitor); five rats never exposed to alcohol were treated with pyrithiamine; four alcohol-exposed rats were treated with thiamine; and four rats never exposed to alcohol were treated with thiamine. On day 14, thiamine was restored in all 18 rats; 2 weeks later the 10 pyrithiamine-treated rats received intraperitoneal thiamine. The rats were perfused 61 days post-pyrithiamine treatment at age 598 days. Brains were dissected and weight and volumes were calculated. Sagittal sections were stained to measure white matter structures. The corpus callosum was examined using transmission electron microscopy to determine density of myelinated fibers, fiber diameter, and myelin thickness. The corpus callosum in the alcohol/pyrithiamine group was significantly thinner, had greater fiber density, higher percentage of small fibers, and myelin thinning than in the alcohol/thiamine and water/thiamine groups. Several measures showed a graded effect, where the alcohol/pyrithiamine group had greater pathology than the water/pyrithiamine group, which had greater pathology than the two thiamine-replete groups. Across all 16 rats, thinner myelin sheaths correlated with higher percentage of small fibers. Myelin thickness and axon diameter together accounted for 71% of the variance associated with percentage of small fibers. Significant abnormalities in the alcohol/pyrithiamine group and lack of abnormality in the alcohol-exposed/thiamine-replete group indicate that thiamine deficiency caused white matter damage. The graded abnormalities across the dually to singly treated animals support a compounding effect of alcohol exposure and thiamine depletion, and indicate the potential for interaction between alcohol and thiamine deficiency in human alcohol-related brain damage.

Nutritional neuropathies

Optimal functioning of the central and peripheral nervous system is dependent on appropriate nutrients. Neurologic consequences of nutritional deficiencies are not restricted to underdeveloped countries. Multiple nutritional deficiencies can coexist. Obesity is of particular concern in the developed world. The rising rate of bariatric surgery are accompanied by neurologic complications related to nutrient deficiencies. Prognosis depends on prompt recognition and institution of appropriate therapy. This review discusses peripheral nervous system manifestations related to the deficiency of key nutrients, neurologic complications associated with bariatric surgery, and conditions that have a geographic significance associated with bariatric surgery and certain conditions that have a geographic predilection.

Alcoholic neuropathy

PURPOSE OF REVIEW

The concept of alcoholic neuropathy has been obscured because of an often undetected or overestimated influence of thiamine deficiency. We describe clinicopathologic features of alcoholic neuropathy, taking the effect of thiamine status into consideration, and recent progress associated with the pathogenesis.

RECENT FINDINGS

Clinical features of alcoholic neuropathy without thiamine deficiency are characterized by slowly progressive, sensory-dominant symptoms. Superficial sensation is predominantly impaired and painful symptoms are the major complaint. Pathologic features are characterized by small-fiber-predominant axonal loss. In contrast, the clinicopathologic features of alcoholic neuropathy with concomitant thiamine deficiency are variable, constituting a spectrum ranging from a picture of a pure form of alcoholic neuropathy to a presentation of nonalcoholic thiamine-deficiency neuropathy. One possible mediator of the direct neurotoxic effects among the metabolites of ethanol is acetaldehyde. Axonal transport and cytoskeletal properties are impaired by ethanol exposure. Protein kinase A and protein kinase C may also play a role in the pathogenesis, especially in association with painful symptoms.

SUMMARY

Nutritional deficiency as well as the direct neurotoxic effects of ethanol or its metabolites can cause alcoholic neuropathy. Although clinicopathologic features of the pure form of alcoholic neuropathy are uniform, they show extensive variation when thiamine deficiency is present.

Myopathy in thiamine deficiency: Analysis of a case

BACKGROUND

Tenderness in the limb muscles has been reported anecdotally in patients with beriberi neuropathy, but clinical effects of thiamine deficiency on skeletal muscle have received little attention.

OBJECTIVE

To describe a patient with thiamine deficiency who manifested myopathic symptoms and responded well to thiamine supplementation.

PATIENT

A 26-year-old woman with neuropathy and heart failure associated with thiamine deficiency also complained of myalgia and weakness, most troublesome in the proximal portions of the limbs.

RESULTS

Serum creatine kinase, myoglobin, and aldolase concentrations were abnormally elevated. Magnetic resonance imaging of lower limb muscles demonstrated areas of high signal intensity in T2-weighted images and showed Gd-DTPA enhancement. A biopsy specimen from the quadriceps muscle showed myopathic changes without neurogenic changes. Abnormalities improved well with thiamine administration.

CONCLUSION

Myopathy may occur in patients with thiamine deficiency.

Additional causes for distal sensory polyneuropathy in diabetic patients

OBJECTIVE

To assess the frequency of additional causes of distal sensory polyneuropathy (DSP) in patients with diabetes mellitus (DM).

METHODS

Retrospective review of patients with DM and DSP during a 5 year period. A quantitative sensory score (QSS) was determined at the initial evaluation and extensive laboratory and EMG studies were performed. Patients with one or more potential causes for DSP were compared to those with DM alone.

RESULTS

Fifty five patients (53%) had potential additional causes for DSP. These included: neurotoxic medications (seven), alcohol abuse (six), and B12 deficiency and renal disease (four each). The most common laboratory abnormalities were: abnormally low levels of vitamin B6 (11) or B1 (10), monoclonal gammopathy (eight), and hypertriglyceridaemia (eight). Twenty six (25%) subjects had more than one additional cause. Nine (9%) had three or more demyelinating features on EMG. There was a trend toward a lower QSS score (p = 0.05) and reduced mean amplitude of the sensory potentials in those with additional causes. Those with additional causes more often had upper limb sensory symptoms (p = 0.001) and sensory findings (p = 0.003).

CONCLUSION

There was a high frequency of additional sources of DSP in patients with DM. These patients more often had sensory symptoms and findings in the hands. Tests that may be useful in the evaluation of DSP in diabetic patients include measures of vitamins B1, B6, B12, serum triglycerides, and immunofixation.

Large and small fiber neuropathy in chronic alcohol-dependent subjects

The aim of the present study was to evaluate the occurrence of large and small fiber neuropathy among alcohol-dependent subjects and to correlate neuropathy with the pattern of alcohol abuse, age of the subjects, nutritional status, and biochemical parameters. The study sample comprised 98 consecutive alcohol-dependent subjects without signs of malnutrition treated for detoxification voluntarily in the specialized unit of the Athens University Psychiatric Clinic in an inpatient basis. Polyneuropathy (PN) was graded using the neuropathy symptoms score and neurologic disability score, conduction velocity studies, and quantitative sensory tests. Seventy-seven men and 21 women aged 27-70 years took part in the study. PN was diagnosed in 57 subjects (58.2%). PN of both large and small fibers was found in 25 patients (25.5%); exclusively small fiber neuropathy was observed in 12 (12.2%) and exclusively large fiber neuropathy in 20 patients (20.4%). Neuropathy was significantly correlated with the age of the subjects, duration of alcohol abuse, liver dysfunction, macrocytosis, and blood sugar levels upon admission. PN was significantly more frequent in males than in females. The two groups of exclusively large and exclusively small fiber neuropathy did not differ significantly in any clinical and laboratory parameter. Subclinical neuropathy (stage 1) was observed in 11.2%, which also did not differ significantly in any clinical and laboratory parameter from the stage 2 PN group subjects. Our findings indicate the direct toxic effect of alcohol on peripheral nerve fibers as the main etiologic factor of alcoholic PN. Long-standing hyperglycemia may be another contributing factor. Impaired vitamin B(12) utilization may be also involved.

Clinicopathologic features of nonsystemic vasculitic neuropathy and microscopic polyangiitis-associated neuropathy: a comparative study

OBJECTIVE

To compare clinicopathologic findings in nonsystemic vasculitic neuropathy (NSVN) and microscopic polyangiitis-associated neuropathy (MPAN).

METHODS

Patients clinicopathologically confirmed to have NSVN (n=23) or MPAN (n=40) were compared with respect to clinical, electrophysiologic, and histopathologic features.

RESULTS

Clinical features of neuropathy such as initial symptoms, progression, and distribution of sensory and motor deficits were similar in both groups, while functional compromise was greater in MPAN than NSVN. Abnormalities of laboratory data including those reflecting severity and extent of inflammation such as C-reactive protein were more conspicuous in MPAN than NSVN. Perinuclear anti-neutrophil cytoplasmic antibodies (p-ANCA) were positive in two-thirds of patients with MPAN but negative in all NSVN. Electrophysiologic and histopathologic findings indicated axonal neuropathy in both groups, whereas the reduction of compound muscle action potentials in the tibial nerve and sensory nerve action potentials in the median nerve was significantly more profound in MPAN than NSVN. As for the epineurial perivascular infiltration, frequencies of cell-specific markers for T lymphocytes, macrophages, and B lymphocytes among cells infiltrating the vasculitic lesions were essentially similar between groups.

CONCLUSIONS

Clinicopathologic profiles and vascular pathology were similar between NSVN and MPAN but the age at onset, severity, and presence of p-ANCA were clearly different. Further study is needed to clarify the pathogenesis of NSVN and its place in the vasculitic spectrum of diseases.

Polyradiculonévrite chronique chez des patients avec une greffe d’organe solide : une étude clinique, neurophysiologique et neuropathologique de 4 cas

INTRODUCTION

Chronic inflammatory demyelinating polyradiculoneuropathy (CIDP) rarely develops in patients with solid organ transplantation.

PATIENTS AND METHOD

We describe the clinical, biological, electrophysiological and neuropathological features of 4 patients with solid organ transplantation who developed CIDP. Two patients had liver transplantation, one had kidney transplantation and one had lung transplantation.

RESULTS

All 4 patients developed in the months following transplantation a syndrome that fulfilled criteria for definite CIDP. All patients had immunosuppressive therapy, with ciclosporin + prednisolone in 2 cases, tacrolimus in 1 case and azathioprine + prednisolone + ciclosporin in one case. One patient had chronic HCV and HBV infection. Treatment with intravenous immune globulin (IVIG) and/or a change in immunosuppressive therapy improved the neuropathy in all cases.

CONCLUSION

CIDP is a rare and potentially treatable condition that should be considered in all patients with solid organ transplantation who develop a rapidly disabling sensorimotor polyneuropathy.

Small fibre neuropathies

PURPOSE OF REVIEW

To summarize the recent advances in aetiology, diagnostic assessment, and treatment of small fibre neuropathies.

RECENT FINDINGS

New causes of small fibre neuropathy have been recognized and advances in neurophysiologic and neuropathologic techniques for investigating small fibres have been made, increasing the interest in this field. In particular, skin biopsy proved to be a sensitive method to diagnose small fibre neuropathy. It allows the detection of subclinical abnormalities of peripheral nerve function in patients with diabetes and tongue denervation in patients with burning mouth syndrome. This technique has also been used to demonstrate the neuroprotective effect of erythropoietin in experimental models of neuropathy. Among nonconventional neurophysiologic techniques for investigating small fibres, laser-evoked potential and contact heat-evoked potential stimulators have been developed and deserve particular interest. Several trials on neuropathic pain that is a typical feature of small fibre neuropathies have been performed and guidelines have recently been published.

SUMMARY

Detection of small fibre impairment allows earlier diagnosis of neuropathy and could be used as an outcome measure in future regenerative neuropathy trials. Standardization of skin biopsy can have an important impact on clinical practice and research. Further studies are needed to assess the reliability of current neurophysiologic techniques for testing small fibre function in peripheral neuropathies and the correlation with well established neuropathologic examination.

Age associated axonal features in HNPP with 17p11.2 deletion in Japan

OBJECTIVE

To clarify age related changes in the clinicopathological features of hereditary neuropathy with liability to pressure palsy (HNPP) in Japanese patients with deletion of 17p11.2, particularly concerning axonal abnormalities.

METHODS

Forty eight proband patients from 48 HNPP families were assessed as to clinical, electrophysiological, and histopathological features, including age associated changes beyond those in controls.

RESULTS

Motor conduction studies showed age associated deterioration of compound muscle action potentials in nerves vulnerable to repetitive compression (median, ulnar, and peroneal nerves), but not in others such as the tibial nerve. Sensory conduction studies revealed more profound reduction of action potentials than motor studies with little age related change. Large myelinated fibre loss was seen in the sural nerve irrespective of age at examination.

CONCLUSIONS

Irreversible axonal damage may occur at entrapment sites in motor nerves in HNPP patients, progressing with aging. Sensory nerves may show more profound axonal abnormality, but without age association. The electrophysiological features of HNPP are presumed to be a mixture of abnormalities occurring from early in life and acquired features caused by repetitive insults at entrapment sites. Unlike Charcot-Marie-Tooth disease type 1A, age associated axonal damage may not occur unless the nerves are subjected to compression.

[Neuropathy with non-alcoholic thiamine deficiency: two cases of bladder disorders]

INTRODUCTION

Neuropathy with non-alcoholic thiamine deficiency is reported in the literature, but bladder disorders are rarely detailed.

CASE REPORTS

We report two cases of bladder disorders in neuropathy with thiamine deficiency. One patient presented with a flaccid bladder and impaired sensation; the postvoid residual volume was raised. The other patient had reduced bladder capacity, with detrusor hyperreflexia and detrusor-sphincter dyssynergia. In both cases, the bladder disorders disappeared with thiamine supplementation.

CONCLUSION

Bladder symptoms may be heterogeneous in nonalcoholic neuropathy. The prognosis is good after vitamin supplementation.

Postgastrectomy polyneuropathy with thiamine deficiency is identical to beriberi neuropathy

OBJECTIVE

We assessed whether postgastrectomy polyneuropathy associated with thiamine deficiency is clinicopathologically identical to beriberi neuropathy, including a biochemical determination of thiamine status.

METHODS

Clinicopathologic features of 17 patients who had postgastrectomy polyneuropathy with thiamine deficiency were compared with those of 11 patients who had thiamine-deficiency neuropathy caused by dietary imbalance.

RESULTS

The typical presentation for the two etiologies was as a symmetric sensorimotor polyneuropathy predominantly involving the lower limbs. A variety of clinical features, including neuropathic symptoms, progression, and coexistence of heart failure or Wernicke's encephalopathy, was seen similarly in both conditions. In both groups, the main electrophysiologic findings were those of axonal neuropathy, most prominently in the lower limbs. Sural nerve biopsy specimens also indicated axonal degeneration in both groups. Subperineurial edema was commonly observed.

CONCLUSION

This study showed that thiamine-deficiency neuropathies due to gastrectomy and dietary imbalance are identical despite variability in their clinicopathologic features and suggested that thiamine deficiency can be a major cause of postgastrectomy polyneuropathy.

Clinical utility of peripheral nerve biopsy

Histopathologic evaluation of nerve biopsy specimens provides important diagnostic information in some patients with peripheral neuropathy. The role of nerve biopsy is more restricted than that of muscle biopsy. Nerve biopsy is utilized mainly for diagnosis of vasculitis and infiltrative neuropathies. It is also utilized in diagnosis of atypical inflammatory demyelinating neuropathies in which the clinical, electrodiagnostic, and laboratory features are inconclusive. In addition, the study of nerve histopathology can also enhance our understanding of disease pathogenesis.

Prolonged central sensory conduction time in alcoholics with hypoactive aldehyde dehydrogenase-2

People who have a Glu487Lys mutation (single nucleotide polymorphism) in the aldehyde dehydrogenase-2 (ALDH2) gene are slow to metabolize the alcohol breakdown product acetaldehyde. The P13/14-N20 interval of the median nerve somatosensory evoked potential was significantly longer in alcoholic patients with a hypoactive ALDH2 (n = 27) than in those with an active ALDH2 (n = 43). This suggests that acetaldehyde accumulation due to hypoactive ALDH2 is associated with a prolongation of the central sensory conduction time between pons and primary sensory cortex. The present result indicates that an elevated blood concentration of acetaldehyde must cause the central sensory tract involvement and that acetaldehyde is one of factors producing brain damage in alcoholics.

Association of aldehyde dehydrogenase-2 polymorphism with alcoholic polyneuropathy in humans

Persons who have the Glu-487-->Lys mutation (single nucleotide polymorphism) of the aldehyde dehydrogenase-2 (ALDH2) gene have less ability to metabolize the alcohol breakdown product acetaldehyde. In order to clarify whether acetaldehyde is associated with the pathogenesis of alcoholic polyneuropathy, we compared nerve conduction data as well as clinical signs and symptoms of neuropathy between alcoholics with ALDH2*2 (Lys-487) heterozygotes and those with ALDH2*1 (Glu-487) homozygotes. Alcoholics with ALDH2*2 heterozygotes showed significantly lower sensory nerve action potential amplitudes of the sural and median nerves than those with ALDH2*1 homozygotes, suggesting that the accumulation of acetaldehyde due to ALDH2 inactivity is associated with alcoholic polyneuropathy.