Atypical presentations of primary amyloid neuropathy

Primary amyloidosis (AL) may be complicated by peripheral neuropathy in 15-35% of cases. We report on four patients with atypical neurological presentations of AL neuropathy, whose diagnoses were delayed due to varied clinical presentations. The clinical presentation included painful sensory neuropathy (two patients), mononeuropathy multiplex (one patient), and primary demyelinating polyneuropathy (one patient). The latter two types of presentation have not been reported previously. The diagnosis was established by fat pad biopsy in two patients, lymph node biopsy in one, and sural nerve biopsy in one. Two patients were treated with high-dose melphalan followed by stem cell rescue, and one was treated with oral melphalan and prednisone. All three cases experienced stabilization of neuropathic symptoms. We report these cases in order to raise awareness of the varied clinical presentation of AL neuropathy.     

Progressive idiopathic axonal neuropathy

Abstract. Patients with a progressive disabling idiopathic axonal neuropathy could have a potentially treatable immune mediated neuropathy. To evaluate whether progressive idiopathic axonal neuropathy could be a pathologically difficult to prove vasculitic neuropathy pathologically difficult to prove or if it could be a separate clinical entity (i. e. with the axon as the primary immunological target), we performed a comparative clinical and histopathological study in 10 patients with progressive idiopathic axonal neuropathy, 10 patients with vasculitic neuropathy, and 12 patients with chronic idiopathic axonal polyneuropathy (CIAP). The clinical features and disease course in patients with progressive idiopathic axonal neuropathy and patients with vasculitic neuropathy were similar. Six patients with progressive idiopathic axonal neuropathy had been treated with prednisone and/or intravenous immunoglobulin. Disability decreased in all these six patients, but also in two of the four non-treated patients. Upon reviewing the sural nerve biopsy specimens, vasculitis was found in one patient with progressive idiopathic axonal neuropathy. Vasculitis-associated signs of ischemic injury or inflammation (most notably: large variation in fascicular axonal degeneration, perivascular inflammation, inflammation of the blood vessel wall without lumen obstruction) were found in four patients with progressive idiopathic axonal neuropathy, in all patients with vasculitic neuropathy, but were absent in patients with CIAP. The findings show that there is a small chance of finding sural nerve vasculitis upon scrutinising biopsy examination in progressive idiopathic axonal neuropathy. The presence of vasculitisassociated signs in progressive idiopathic axonal neuropathy suggests that some of these patients could have vasculitic neuropathy, even if vasculitic lesions cannot be demonstrated. However, if inflammatory changes cannot be demonstrated this does not preclude an immune-mediated origin.     

Sensory CIDP presenting as cryptogenic sensory polyneuropathy

The objective of this study was to report that patients with chronic inflammatory demyelinating polyneuropathy (CIDP) can present with a clinical picture of cryptogenic sensory neuropathy. Patients with distal sensory neuropathy and electrodiagnostic studies that are minimally abnormal or consistent with an axonal pathology are usually diagnosed as having cryptogenic sensory neuropathy if no cause for neuropathy can be found. Some of these patients, however, may have sensory CIDP. We reviewed the records of eight patients with CIDP, diagnosed by sural nerve biopsy, who presented with sensory neuropathy and electrodiagnostic studies that were minimally abnormal or revealed changes consistent with axonal neuropathy. All patients reported distal numbness and paresthesias and, on examination, had predominantly large fiber distal sensory loss and normal muscle strength. In most patients, deep tendon reflexes were reduced or absent. Sural nerve biopsies in all patients were consistent with chronic myelinopathy, with quantitative teased fiber analysis revealing segmental remyelination in 13-40% of the fibers. The four patients who received IVIg therapy had improved sensation and gait. Of the remaining four patients, one is being followed, one had spontaneous remission, one was lost to follow-up, and one, with contraindications to therapy, reported disease progression. Sensory CIDP may present as cryptogenic sensory polyneuropathy with normal or axonal electrophysiologic features. Sural nerve biopsy should be considered in patients with progressive, predominantly large fiber sensory neuropathy of otherwise unknown etiology, as they may have sensory CIDP that responds to therapy.     

家族性淀粉样多发性神经病(3个家族13例患者,3例病理证实并文献复习)

目的 结合文献复习，探讨家族性淀粉样多发性神经病的发病机制和临床特征。方法 报道3个台湾籍家系共13例患者，对每个家系的先证者进行临床分析。结果 本组所有患者临床上均表现为植物神经症状，如排尿障碍、胃肠症状和阳痿等，体格检查提示为严重的感觉运动神经病、体位性低血压和消瘦。神经电生理检查提示周围神经和神经根轴索损害及脱髓鞘改变。病理学检查发现3例先证者均有剐果红染色阳性的淀粉样物沉积于神经束间质及神经内膜中。结论 对于进行性发展的伴突出植物神经症状的慢性周围神经病，若有多脏器功能受损及阳性家族史，应考虑本病，病理检查有重要意义。     

Peroneal neuropathy after weight loss

The objectives of this study were to evaluate the clinical and electrophysiological findings in peroneal mononeuropathies following a weight-reduction diet. Thirty patients with acute peroneal palsy and weight loss were studied. Complete nerve conduction studies (NCS) were performed in upper and lower limbs. NCS showed conduction block (CB) of the peroneal nerve at the fibular head that recovered in 29 patients within 3 weeks to 3 months. Severity of CB was correlated with clinical weakness. Three patients had abnormalities consistent with polyneuropathy (PNP). NCS in asymptomatic relatives confirmed familial neuropathy. Nerve biopsy and molecular study were consistent with hereditary neuropathy with liability to pressure palsies (HNPP). One of these peroneal palsies (6 months) recovered after neurolysis. Weight loss might be a risk factor in peroneal mononeuropathies. NCS is a tool in the diagnosis of the site and severity of the nerve injury. Testing should be considered for relatives of patients with PNP because peroneal mononeuropathies may be the first expression of HNPP.     

Nerve conduction studies in spastic paraplegia,optic atrophy,and neuropathy (SPOAN) syndrome

Introduction: SPOAN (spastic paraplegia, optic atrophy, and neuropathy) syndrome is an autosomal recessive neurodegenerative disorder identified in a large consanguineous Brazilian family. Methods: Twenty‐seven patients with SPOAN syndrome (20 women), aged 4–58 years, underwent nerve conduction studies (NCS) of the median, ulnar, tibial, and fibular nerves, and sensory NCS of the median, ulnar, radial, sural, and superficial fibular nerves. Results: Sensory nerve action potentials were absent in the lower limbs and absent in >80% of upper limbs. Motor NCS had reduced amplitudes and borderline velocities in the upper limbs and absent compound muscle action potentials (CMAPs) in the lower limbs. Conclusions: The neuropathy in SPOAN syndrome is a severe, early‐onset sensory–motor axonal polyneuropathy. Normal NCS seem to rule‐out this condition. Muscle Nerve 49 : 131–133, 2014     

Medial plantar and dorsal sural nerve conduction studies increase the sensitivity in the detection of neuropathy in diabetic patients.

OBJECTIVE: Clinical utility of nerve conduction studies (NCS) of the medial plantar and dorsal sural nerves in the early detection of polyneuropathy have already been shown separately. However, at present, there is no data about the combined assessment of these two nerves in distal sensory neuropathy. In the present study, we aimed to evaluate the medial plantar and dorsal sural NCS in a group of diabetic patients with distal sensory neuropathy (DSN) and in healthy controls. METHODS: Thirty healthy and 30 diabetic adult patients were included. In all subjects, peripheral motor and sensory NCS were performed bilaterally with surface electrodes on the lower limbs including medial plantar and dorsal sural nerves. In addition, motor and sensory nerves were studied unilaterally on the upper limb. RESULTS: In all patients, nerve action potential (NAP) amplitudes of sural and superficial peroneal nerves were within normal ranges, but in the patient group mean value was significantly lower than in the controls. Among clinically defined 30 DSN patients, medial plantar NAP amplitude was abnormal in 18 (60%) and dorsal sural nerve amplitude was abnormal in 13 (40%) of the patients bilaterally. Additionally, the onset NCV of the dorsal sural nerve was significantly slower in patients than controls (P=0.038). Evaluation of both of these nerves increased the sensitivity up to 70% in the detection of neuropathy. CONCLUSIONS: Bilateral NCS assessment of both of the medial plantar and dorsal sural nerves together increases the rate of diagnosis of diabetic distal sensory neuropathy compared to assessment of either of these nerves. SIGNIFICANCE: Assessment of medial plantar in addition to dorsal sural NCS together increases the sensitivity in the detection of neuropathy and allows earlier diagnosis, especially when routine NCS are normal.     

Immune reactive C3d on the surface of myelin sheaths in neuropathy

Immunofluorescence studies of sural nerve demonstrated immune reactive C3d and IgM on the surface of myelin sheaths in seven patients with neuropathy and an anti-myelin-associated glycoprotein (MAG) IgM M-protein. Similar deposits of C3d and sometimes IgM were found in four of six patients with acute or chronic inflammatory demyelinating polyneuropathy and in three of six patients with vasculitic neuropathy (including one with acquired immunodeficiency syndrome (AIDS)). C3d was not found in 80 patients with other peripheral nerve disorders except for two with metachromatic leukodystrophy. None of the C3d deposits contained immune reactive C3c implying substantial degradation of C3b. C3d is a sensitive index of complement activation in nerve and may be useful in classification of neuropathies.     

Axonal neuropathy due to myelin protein zero mutation misdiagnosed as amyloid neuropathy

In up to 50% of chronic idiopathic axonal neuropathies, an underlying diagnosis may be identified, including hereditary neuropathy. Charcot-Marie-Tooth disease (CMT) is clinically and genetically heterogeneous. Several mutations in the myelin protein zero (MPZ) gene have been associated with different CMT phenotypes, including classical demyelinating CMT1B and the axonal form of the disease. Primary amyloidosis, a rare disease where the amyloid is formed by the N-terminal portion of a monoclonal immunoglobulin light chain, may be complicated by polyneuropathy. We report a patient who was incorrectly diagnosed with amyloid neuropathy, but was found to have axonal CMT1B only after sural nerve biopsy ruled out an acquired amyloid neuropathy.     

Pseudo-conduction blocks in a case with polyarteritis nodosa

A 43-year-old female was referred to our clinic for an electromyographic (EMG) examination due to weakness in both the lower extremities. Conduction blocks were indicated through nerve conduction studies (NCS). Because of demyelinating polyneuropathy findings and elevated protein levels in the cerebrospinal fluid (CSF), the patient was diagnosed with acute inflammatory demyelinating polyneuropathy (AIDP) and was treated with intravenous immunoglobulin. In the follow-up examination, a distal quadriparesis was found that was markedly pronounced in the lower left extremity, and a second EMG examination showed asymmetrical worsening. These findings combined with the lack of demyelination suggested axonal degeneration, and the partial conduction blocks observed during the first NCS were determined to be pseudo-blocks. Vasculitic syndromes were considered and the associated laboratory tests were performed. Following a sural nerve biopsy, non-infectious necrotizing arteritis was found and the patient was diagnosed with polyarteritis nodosa (PAN). Therefore, clinicians should be aware that conduction blocks observed in nerve conduction studies may potentially be pseudo-blocks and an indication of vasculitic neuropathy.     

Acute flaccid paralysis: Do not forget beriberi neuropathy

We aimed to elucidate characteristics of beriberi neuropathy (BB) in a general hospital (GH) setting. Nerve conduction studies (NCS), cross‐referenced with clinical records of patients admitted to a GH (May 2011‐July 2017), were reviewed for diagnosis of BB. Thirteen patients (age range 23‐64 years; five women) were diagnosed with BB. Eleven were incarcerated (2‐24 months) at time of index event. Eleven reported prior, severe anorexia (2‐6 months); five reported significant weight loss, three had recurrent vomiting, and three reported alcohol misuse. Commonest presentation was weakness (12/13); nine had symptom evolution over ≥3 weeks. At nadir, 11/13 could not walk independently. Other features included numbness/paraesthesiae (10/13), dysautonomia (6/13), vocal cord dysfunction/dysphagia (4/13), nystagmus (3/13). Pain was not prominent. Cerebrospinal fluid, tested in five patients, was acellular; one showed mildly increased protein. NCS showed predominantly sensorimotor, axonal polyneuropathy, rarely asymmetric. Only one patient had sural‐sparing pattern. All received high dose thiamine. Two of the thirteen received intravenous immunoglobulin for suspicion of Guillain‐Barré syndrome (GBS). Eleven improved to independent ambulation. One patient died from pulmonary embolism; one was lost to follow‐up. Two of the thirteen had residual neurocognitive effects; both misused alcohol. Besides GBS, BB is an important cause of acute to subacute flaccid paralysis, especially in incarcerated patients and those with significant dietary deprivation. Features favoring BB over GBS are ≥3 weeks of symptoms, nystagmus, confusion, vocal cord dysfunction, volume overload, normal spinal fluid, elevated lactate, and absence of sural‐sparing pattern in NCS.     

Impact of aging on the progression of neuropathy after liver transplantation in transthyretin Val30Met amyloidosis

Introduction: Information related to the long‐term follow‐up of neuropathy in patients with familial amyloid polyneuropathy after liver transplantation is still scarce. Methods: We describe the neuropathic features of 3 patients with the transthyretin Val30Met mutation. Each patient underwent liver transplantation at an early stage of neuropathy, as indicated by the absence of motor dysfunction and relative preservation of myelinated fibers in sural nerve biopsy specimens. Results: Although the patient with late‐onset disease (at age 60 years) presented with the least amount of amyloid deposition, he had neuropathic progression after liver transplantation. An older early‐onset (at age 40 years) patient reported a slight exacerbation of both somatic and autonomic neuropathic symptoms 10 years after transplantation. However, the younger early‐onset (at age 28 years) patient did not exhibit characteristics suggestive of neuropathy 7 years after transplantation. Conclusion: Aging may determine the progression of neuropathy after liver transplantation. Muscle Nerve, 2012     

Polyneuropathy in lithium intoxication

Two patients developed acute sensorimotor polyneuropathy after intoxication with lithium carbonate. Nerve conduction studies, electromyography, and sural nerve biopsy proved it to be an axonal neuropathy. Recovery of muscle strength, reflexes, and sensory function started weeks after discontinuation of lithium therapy. One patient fully recovered within a year. In the literature we found nine other cases of lithium polyneuropathy.     

A case of inflammatory demyelinating polyradiculoneuropathy associated with T-cell lymphoma

Malignant lymphoma may present prominent peripheral nervous system disorders with variable etiologies. We describe a patient who presented with chronic relapsing polyradiculoneuropathy accompanied by right facial nerve palsy. Gadolinium enhancement of the right facial nerve and cervical spinal roots was noted on magnetic resonance imaging (MRI). Sural nerve biopsy specimens showed mononuclear cell infiltration around the vessels in the epineurium. Histopathological and immunohistochemical investigations of sural nerve specimens revealed perivascular infiltration of lymphocytes with T-cell dominancy. No apparent direct invasion of lymphoma cells was seen. The results of nerve conduction studies, sural nerve biopsy and cerebrospinal fluid examination were suggestive of immune-mediated inflammatory demyelinating neuropathy. The chronic and relapsing fashion and unique radiological findings in our patient expand on the previously reported features of peripheral neuropathy associated with peripheral T-cell lymphoma.     

Rapid genetic screening of Charcot-Marie-Tooth disease type 1A and hereditary neuropathy with liability to pressure palsies patients

We used the allele-specific PCR-double digestion method on peripheral myelin protein 22 (PMP22) to determine duplication and deletion mutations in the proband and family members of one family with Charcot-Marie-Tooth disease type 1 and one family with hereditary neuropathy with liability to pressure palsies. The proband and one subclinical family member from the Charcot-Marie-Tooth disease type 1 family had a PMP22 gene duplication; one patient from the hereditary neuropathy with liability to pressure palsies family had a PMP22 gene deletion. Electron microscopic analysis of ultrathin sections of the superficial peroneal nerve from the two probands demonstrated demyelination and myelin sheath hyperplasia, as well as an ’onion-like’ structure in the Charcot-Marie-Tooth disease type 1A patient. We observed an irregular thickened myelin sheath and ’mouse-nibbled’-like changes in the patient with hereditary neuropathy with liability to pressure palsies. In the Charcot-Marie-Tooth disease type 1A patient, nerve electrophysiological examination revealed moderate-to-severe reductions in the motor and sensory conduction velocities of the bilateral median nerve, ulnar nerve, tibial nerve, and sural nerve. Moreover, the compound muscle action potential amplitude was decreased. In the patient with hereditary neuropathy with liability to pressure palsies, the nerve conduction velocity of the bilateral tibial nerve and sural nerve was moderately reduced, and the nerve conduction velocity of the median nerve and ulnar nerve of both upper extremities was slightly reduced.     

The peripheral neuropathy of vitamin B12 deficiency

Nerve conduction studies and sural nerve biopsy were performed on three patients with vitamin B12 deficiency and symptoms of peripheral neuropathy. The pathological findings were those of axonal degeneration; there was no evidence of demyelination. The patients were reviewed at intervals of 5-15 years commencement of treatment; progression of the neuropathy had been arrested by treatment, but in all cases residual neurological abnormalities persisted. In one patient with autonomic neuropathy, the postural hypotension resolved rapidly and fully with treatment.     

Physiologic-pathologic correlation in Guillain-Barré syndrome in children

OBJECTIVE: To correlate electrophysiologic patterns with sural nerve pathology in children with Guillain-Barré syndrome (GBS). BACKGROUND: Based on electrophysiologic and pathologic observations, GBS has been divided into demyelinating and axonal subtypes. The acute motor axonal neuropathy (AMAN) involves predominantly motor nerve fibers with a physiologic pattern suggesting axonal damage, whereas the acute inflammatory demyelinating polyneuropathy (AIDP) involves both motor and sensory nerve fibers with a physiologic pattern suggesting demyelination. In this study, we sought to confirm these observations by correlating sural nerve pathology with electrophysiologic findings in GBS patients. METHODS: Biopsies of sural nerve from 29 of 50 prospectively studied GBS patients were obtained. Nerves were examined by light and electron microscopy, and with immunocytochemistry for macrophages, lymphocytes, and complement activation products. RESULTS: Sural nerves from AMAN patients were normal or had only a few (0.1% to 0.7%) degenerating fibers without lymphocytic infiltration or complement activation. One patient with reduced sural sensory nerve action potential classified as acute motor sensory axonal neuropathy (AMSAN) had many degenerating fibers (2.3%) in the sural nerve. All three AIDP patients displayed active demyelination, and in two patients, lymphocytic infiltration and complement activation products were observed on the abaxonal Schwann cell surface. CONCLUSION: Classification of Guillain-Barré syndrome subtypes based on motor conduction studies correlates closely with pathologic changes seen in sural nerve. In acute motor axonal neuropathy cases, the sural nerve is almost completely spared pathologically. In acute inflammatory demyelinating polyneuropathy cases, macrophage-mediated demyelination and lymphocytic infiltration are common in the biopsies of sural nerves.     

Superficial radial sensory nerve potentials in immune-mediated and diabetic neuropathies.

OBJECTIVE: The pattern of abnormal median-normal sural sensory nerve action potential (SNAP) is frequently found in acute/chronic inflammatory demyelinating polyneuropathy (AIDP/CIDP), whereas sural/radial SNAP amplitude ratio is sensitive to detect dying-back degeneration. To investigate whether radial SNAP and its amplitude ratio to median or sural SNAP provide additional particular patterns of sensory nerve involvement. METHODS: Superficial radial, median, and sural SNAPs were recorded in 63 normal subjects and in 132 patients with AIDP/CIDP (n = 22), diabetic neuropathy (n = 83), or other axonal polyneuropathy (n = 27). Median/radial and sural/radial amplitude ratios were examined. RESULTS: In normal subjects, median/radial ratio was 0.96 +/- 0.05 (mean +/- SEM), and sural/radial ratio was 0.50 +/- 0.03. Compared with normal controls, the median/radial ratio was lower in patients with AIDP/CIDP (0.64 +/- 0.11; P < 0.001) or diabetic neuropathy (0.75 +/- 0.04; P = 0.08), but similar in those with other neuropathy (0.94 +/- 0.10). The sural/radial ratio was higher in the AIDP/CIDP group (0.71 +/- 0.08; P = 0.10), and lower in the diabetic (0.36 +/- 0.03; P < 0.001) and other axonal neuropathy groups (0.40 +/- 0.07; P = 0.08). CONCLUSIONS: AIDP/CIDP is associated with a reduced median/radial ratio and increased sural/radial ratio, probably reflecting demyelination predominant in the distal nerve terminals. Diabetic neuropathy is characterized by decreases in both median/radial and sural/radial ratios, presumably due to coexistence of carpal tunnel pathology and dying-back degeneration. SIGNIFICANCE: Comparison of multiple SNAP amplitudes provides information about characteristic distribution patterns of sensory nerve involvement in peripheral neuropathies.     

Electrophysiological findings of peripheral neuropathy in newly diagnosed type II diabetes mellitus

This study was aimed at assessing the electrophysiological signs of peripheral neuropathy in diabetes mellitus (DM) type II patients at diagnosis. Nerve conduction studies (NCS) of median, ulnar, peroneal, tibial and sural nerves were performed in 39 newly diagnosed DM subjects and compared to those of 40 healthy controls. Metabolic indices were also investigated. Electrophysiological alterations were found in 32 (82%) of the DM patients, and more than half of them (62.2%) showed multiple (two to five) abnormal parameters. Because most of the subjects (84.4%) had from two to five nerves involved, these alterations were widespread in the seven nerves evaluated. Forty-two percent of the patients had NCS alterations suggestive of distal median mononeuropathy, implying that metabolic factors in DM make the median nerve more susceptible to focal entrapment. A reduced sensory nerve action potential (SNAP) amplitude was observed in the median nerve in 70% of the patients, in the ulnar in 69% and in the sural nerve only in 22%. In the presence of a decrease in the SNAP amplitude of the ulnar or median nerve, the SNAP amplitude of the sural nerve was normal in 82 or 80% of the subjects, respectively. This finding may be in keeping with a distal involvement of the sensory fibres, as explored by routine median or ulnar NCS. No correlation was found between metabolic indices and NCS parameters. In conclusion, a high percentage of newly diagnosed DM patients show signs of neuropathy, and upper limb nerve sensory NCS seem to be more sensitive in detecting it than lower limb NCS.     

Myelin uncompaction and axo‐glial detachment in chronic ataxic neuropathy with monospecific IgM antibody to ganglioside GD1b

To describe clinical features, disease course, treatment response, and sural nerve biopsy findings in a patient with chronic sensory ataxic neuropathy, Binet stage A chronic lymphocytic leukemia, and monoclonal IgMλ paraprotein against ganglioside GD1b. During 9 months of hospitalization at two neurologic centers, the patient underwent serial neurologic examinations, neurophysiologic studies, imaging investigations, extensive laboratory work‐up, bone marrow, and sural nerve biopsies. The patient had a severe progressive sensory neuropathy accompanied by motor involvement, dysautonomia, and marked bulbar weakness with preserved ocular movements. Conduction studies were characterized by prolonged F‐wave minimal latencies, prolonged distal latencies, reduction of compound motor action potentials, and absence of sensory nerve action potentials. Sural nerve biopsy showed endoneurial edema, axonal degeneration, and regeneration, in the absence of cellular inflammation, macrophagic activation, and B‐lymphocyte infiltration; no IgM or complement deposition was detected. Myelinated fibers showed redundant/abnormally thickened myelin, myelin vacuolation, and frank intramyelinic edema with condensed axoplasm. Ultrastructural features included axo‐glial detachment, disruption of membrane integrity, and myelin uncompaction. This study shows that monospecific anti‐GD1b IgM paraprotein is associated with non‐inflammatory nerve damage. We suggest that the loss of myelin and axonal integrity reflects antibody‐induced disruption of membrane lipid rafts.