Abnormal sweating patterns associated with itching, burning and tingling of the skin indicate possible underlying small-fibre neuropathy.

BACKGROUND: Itching, burning, numbness and tingling of the skin are frequent reasons for dermatology consultation. We hypothesized that these sensations may be attributable to a small-fibre neuropathy. Sweating, which is mediated by small nerve fibres, may be a surrogate marker of small-fibre neuropathy. OBJECTIVES: To investigate the results of thermoregulatory sweat testing (TST), which depicts and estimates whole-body sweating, in patients with itching, burning, numbness and tingling sensations. METHODS: We retrospectively reviewed the medical records of 227 patients with itching, burning, numbness and tingling sensations involving the skin who were seen at our institution during 2008 and also underwent TST. RESULTS: The mean age of the cohort was 54 years (range 3-89), and 58% were female. In all, 149 patients (66%) had abnormal TST results; in 119 (80%) of these patients the areas of anhidrosis on TST corresponded to their symptomatic areas. For each symptom analysed separately, the area of anhidrosis correlated with the area of symptoms in most patients. CONCLUSIONS: Patients with burning, itching, numbness and tingling have abnormal sweating patterns and often do not sweat in the symptomatic areas. These novel findings suggest that a small-fibre neuropathy may underlie many cutaneous symptoms and that the neuropathy can be estimated using TST.

Pharmacodynamics of midodrine, an antihypotensive agent.

Midodrine is an orally active adrenergic agonist useful in the treatment of hypotension. We have investigated the pharmacodynamics of its active metabolite after oral midodrine therapy in nine patients with severe orthostatic hypotension. Peak plasma levels of the metabolite were reached in 60 to 90 minutes and ranged from 25 to 56 ng/ml. The mean values for distribution volume, plasma clearance, and t1/2 were 4.0 L/kg, 23 ml/min/kg, and 2.1 hours, respectively. Heart rate increased after 5 to 10 mg doses and the increases were statistically significant (P less than 0.05) at 120 minutes. An apparent increase in blood pressure was not statistically significant. The patients said that they felt better.

Idiopathic autonomic neuropathy: clinical, neurophysiologic, and follow-up studies on 27 patients.

We evaluated the natural history, electrophysiologic characteristics, spectrum of autonomic involvement, pathology, and laboratory features in 27 patients with idiopathic autonomic neuropathy who were followed up for a mean of 32 months. The typical features of idiopathic autonomic neuropathy include the absence of an associated disease, frequent history of preceding infection, and acute or subacute onset with a monophasic course. The spectrum of autonomic involvement ranges from panautonomic to selective adrenergic or cholinergic failure. There is infrequent involvement of somatic nerve fibers as assessed by routine nerve conduction studies. Pathologic features include the presence of a small inflammatory mononuclear cell infiltrate in the epineurium. Recovery tends to be gradual and frequently incomplete. The acute onset, frequent antecedent viral infection, selectivity of involvement by fiber type and autonomic level, and presence of perivascular mononuclear cell infiltration suggest that the underlying mechanism is likely to be immune-mediated. These observations may justify plasma exchange or other immunosuppressive modalities as early therapeutic intervention in patients with progressive disability.

Ten steps in characterizing and diagnosing patients with peripheral neuropathy.

Cost-effective approaches for arriving at correct diagnoses should be used. Herein, we compare three approaches for the differential diagnosis of a common neurologic syndrome, peripheral neuropathy. In the "shotgun" approach, a standard battery of hematologic, biochemical, serologic, antibody, enzyme, molecular genetic, and other tests are ordered after the presence of a neuropathy is established, without a detailed characterization of the neuropathy. In the "gestalt" approach, the specific variety of neuropathy is identified by recognition of a clinical pattern of symptoms, course, or disease associations. The "10-step" approach, encompassing components of the two other methods and adding others, evolved from our assessment of many patients with peripheral neuropathy. In the 10-step approach, the history and neurologic examination place the patient's disorder into one of perhaps 21 anatomic-pathologic patterns. Next, electrophysiologic and other tests confirm the correctness of this anatomic-pathologic patterns. Finally, a series of evaluations exclude or include an increasingly shorter list of diagnoses until only one likely one remains or the disorder remains undiagnosed. We advocate the 10-step over the shotgun or gestalt approach, because it emphasizes careful initial characterization of neuropathy and emphasizes use of a logical step-by-step inclusion or exclusion to arrive at a short list of diagnostic possibilities. The approach depends ultimately on the judgement of adequately trained and experienced physicians, not on the results of single tests. The 10-step approach is not a mindless algorithm, leading inevitably to the correct diagnosis, but depends on judgment based on extensive background and neurobiologic and clinical knowledge and training.

The splanchnic autonomic outflow in amyloid neuropathy and Tangier disease.

The splanchnic outflow is important in the maintenance of postural normotension in humans. Pathology of outflow is usually associated with postural hypotension. Morphometric analyses were performed on the intermediolateral column neuron cell bodies at the T7 level in four cases of amyloid neuropathy and one case of Tangier disease. In amyloid neuropathy, postural hypotension is common; cell counts were reduced and ranged from 50 to 79% of control values. In Tangier disease, postural hypotension has not been reported; cell counts were normal.

Neuronal nicotinic ACh receptor antibody in subacute autonomic neuropathy and cancer-related syndromes.

BACKGROUND: Autoantibodies specific for the acetylcholine receptor (AChR) of skeletal muscle (containing the alpha1 subunit) impair neuromuscular transmission in myasthenia gravis (MG). AChRs mediating fast synaptic transmission through autonomic ganglia are structurally similar to muscle AChR, but contain the alpha3 subunit. We propose that ganglionic AChR autoimmunity may cause dysautonomia. OBJECTIVE: To test serum of patients with autonomic neuropathy for autoantibodies of neuronal ganglionic AChR specificity. METHODS: We developed an immunoprecipitation radioassay by complexing epibatidine (125I-labeled high affinity agonist) to a Triton X-100-solubilized AChR antigen from peripheral neuroblastoma membranes. Monoclonal rat immunoglobulins (IgG) specific for muscle or neuronal AChRs validated the assay's specificity. We tested serum from 52 healthy subjects, 12 patients with subacute autonomic neuropathy, and 248 patients with other neurologic disorders. RESULTS: Twelve patients had antibodies that bound unequivocally to ganglionic AChR. Five had subacute autonomic neuropathy, and three (of six tested) had Isaacs' syndrome; four of these eight had a carcinoma (lung, bladder, rectum, thyroid). The remaining four seropositive patients (two Lambert-Eaton syndrome, one dementia, one sensory neuronopathy) all had Ca2+ channel antibodies and three had small cell lung carcinoma. No healthy subject had ganglionic AChR antibodies, nor did 62 patients with MG and muscle AChR antibodies. CONCLUSION: Neuronal AChR antibodies are a novel serologic marker of neurologic autoimmunity. The pathogenicity of neuronal AChR autoantibodies in autonomic neuropathy, Isaacs' syndrome, or other neurologic disorders remains to be shown, as has been demonstrated for muscle AChR antibodies in MG. An autoimmune and potentially paraneoplastic etiology is implicated in seropositive patients.

Utility of thermography in the diagnosis of lumbosacral radiculopathy.

We performed infrared telethermography in 55 patients with the clinical diagnosis of lumbosacral radiculopathy and in 37 normal controls. Five readers interpreted the thermograms in a blinded fashion. A moderate degree of agreement was noted in tests of intraobserver and interobserver variability. The sensitivity of thermography ranged from 78% to 94% compared with 81% to 92% for imaging studies and 77% for EMG. The specificity of thermography ranged from 20% to 44%. Thermography predicted the level of the radiculopathy correctly in less than 50% of cases. Thermography has little or no utility in the diagnosis of lumbosacral radiculopathy.

Orthostatic hypotension.

This article reviews the physiology and pathology of orthostatic blood pressure regulation. It describes the diverse clinical disorders of postural blood pressure adjustment, focusing attention on idiopathic orthostatic hypotension and the Shy-Drager syndrome, with emphasis on clinical aspects, pharmacology, and pathologic anatomy. Proposals are made for the diagnostic evaluation of patients with orthostatic hypotension and for steps to be taken in therapeutic management.

Midodrine. A new agent in the management of idiopathic orthostatic hypotension and Shy-Drager syndrome.

Five patients with idiopathic orthostatic hypotension, two of whom had central nervous system manifestations (Shy-Drager syndrome), were treated with midodrine, an investigational alpha-adrenergic agonist, in a dosage of 2.5 to 5 mg three times daily. Significant improvement was observed in the standing systolic and diastolic blood pressures at the end of 1 week of therapy in all patients and has been maintained for 10 to 15 months in all patients. No symptomatic side effects were noted. Supine systolic hypertension occurred in two patients and was treated with small doses of metoprolol.

Thermoregulatory sweating abnormalities in diabetes mellitus.

A properly performed thermoregulatory sweat test (TST) can be informative in patients with diabetic neuropathy. Of 51 patients suspected of having neuropathy on the basis of a clinical examination, 48 (94%) had unequivocal abnormalities on the TST. Pathologic loss of sweating occurred distally in 65%, segmentally in 25%, and only in isolated dermatomes in 25%; 78% of patients had a combination of two or more patterns. Global anhidrosis was noted in eight patients (16%), all of whom had profound autonomic neuropathy, and in the entire group, the percentage of body surface anhidrosis correlated with the degree of clinical dysautonomia (rank correlation coefficient = 0.77; P less than 0.01). Discrete zones of anhidrosis on the thorax and abdomen were noted in patients with painful diabetic radiculopathy, and they correlated highly with thoracic paraspinal muscle fibrillation potentials. Distal loss of sweating detected on the TST was always associated with a subnormal quantitative sudomotor axon reflex response or abnormal electromyographic findings, an indication of a distal axonal neuropathy. The TST provides reliable information about the distribution of diabetic neuropathic involvement and can be especially useful in the diagnosis of truncal radiculopathy and clinically significant autonomic neuropathy.

Recurrent lumbar ependymoma presenting as headache and communicating hydrocephalus.

We describe a patient with a recurrent spinal cord ependymoma who initially presented with symptoms of increased intracranial pressure rather than symptoms directly relating to involvement of the conus medullaris. Brain magnetic resonance imaging with gadolinium showed communicating hydrocephalus. Magnetic resonance imaging of the entire spinal cord with gadolinium revealed recurrent tumor. Postoperatively, a permanent ventriculoperitoneal shunt was placed. Recognition of the association between spinal cord ependymoma and hydrocephalus is important in the evaluation of patients with headache.

Evaluation of skin vasomotor reflexes by using laser Doppler velocimetry.

We used a laser Doppler velocimeter for measurement of skin blood flow in 63 healthy control subjects and in patients with dysautonomias. We measured vasoconstrictor responses to inspiratory gasp, standing, Valsalva maneuver, and cold stimulus. An abnormal profile was defined in terms of the percentage of abnormal test results, the results of individual tests, and the alterations in the shape of the recorded response. These measurements of vasomotor function may permit the diagnosis of focal abnormalities of peripheral nerve sympathetic failure.

Hyperbaric treatment of cerebral air embolism sustained during an open-heart surgical procedure.

A case of cerebral air embolism sustained during replacement of the mitral valve resulted in postoperative coma and seizures. Hyperbaric treatment, begun 30 hours after the occurrence of the air embolism, resulted in good immediate and long-term recovery. Mild deficits of the left hemisphere were present at follow-up 53 days after the embolus was sustained, and lesser, minimal residua were present at 14-month follow-up. Hyperbaric treatment is the definitive therapy for cerebral air embolism. Although it is most effective when administered early, the outcome may be excellent even with late treatment.

Prospective evaluation of clinical characteristics of orthostatic hypotension.

OBJECTIVE: To undertake a prospective study of the clinical characteristics of orthostatic intolerant patients referred to the Mayo Autonomic Reflex Laboratory with suspected orthostatic hypotension (OH). DESIGN: Autonomic function tests were performed to quantify the severity of sudomotor, adrenergic, and cardiovagal failure and generate a composite autonomic symptom score (CASS). CASS was related to a symptom score, which was derived from the frequency of orthostatic intolerance and syncope and the standing time until occurrence of symptoms. RESULTS: Three groups were defined by their response to a tilt study: group I, 90 patients with symptomatic OH, mean age, 63.6 years; group II, 60 patients who had symptoms without OH, mean age, 48.9 years; and group III, 5 patients with asymptomatic OH, mean age, 68.0 years. Group I had a significantly higher CASS (P < 0.001) than did those without OH. Further analysis was done on the 90 patients in group I. The most common symptoms were lightheadedness, weakness, impaired cognition, visual blurring, tremulousness, and vertigo. The most common aggravating factors were prolonged standing, exercise, warming, and eating. Most patients (75%) could stand for less than 5 minutes before symptoms occurred. Symptoms regressed significantly with CASS but not with the tilt grade. CONCLUSION: Patients with generalized autonomic failure have a recognizable pattern of symptoms and aggravating factors that relate, albeit imperfectly, to the severity of autonomic failure.

Successful treatment of POEMS syndrome with autologous hematopoietic progenitor cell transplantation.

POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal gammopathy, and skin changes) is a plasma cell dyscrasia that differs substantially from classic multiple myeloma. It is often associated with disabling polyneuropathy in younger patients. Current therapeutic approaches are frequently inadequate and leave many patients wheelchair-bound with significant deterioration in quality and length of life. We present the case of a young man with progressive disease despite conventional therapeutic approaches. We describe a novel approach to treatment with a bone-seeking radiopharmaceutical, samarium-153 ethylene diamine tetramethylene phosphonate ((153)Sm-EDTMP), followed by myeloablative chemotherapy with autologous hematopoietic progenitor cell reconstitution. This approach resulted in regression of the organomegaly and skin changes and in neurologic improvement both clinically and electrophysiologically. The patient progressed from being wheelchair-bound to independent ambulation. An aggressive approach should be considered in patients with POEMS syndrome in whom standard therapeutic measures fail.

Immunotherapy trial as diagnostic test in evaluating patients with presumed autoimmune gastrointestinal dysmotility.

BACKGROUND: Chronic gastrointestinal dysmotility greatly impacts the quality of life. Treatment options are limited and generally symptomatic. Neural autoimmunity is an under-recognized etiology. We evaluated immunotherapy as an aid to diagnosing autoimmune gastrointestinal dysmotility (AGID). METHODS: Twenty-three subjects evaluated at the Mayo Clinic for suspected AGID (August 2006-February 2014) fulfilled the following criteria: (1) prominent symptoms of gastrointestinal dysmotility with abnormalities on scintigraphy-manometry; (2) serological evidence or personal/family history of autoimmune disease; (3) treated by immunotherapy on a trial basis, 6-12 weeks (intravenous immune globulin, 16; or methylprednisolone, 5; or both, 2). Response was defined subjectively (symptomatic improvement) and objectively (gastrointestinal scintigraphy/manometry studies). KEY RESULTS: Symptoms at presentation: constipation, 18/23; nausea or vomiting, 18/23; weight loss, 17/23; bloating, 13/23; and early satiety, 4/23. Thirteen patients had personal/family history of autoimmunity. Sixteen had neural autoantibodies and 19 had extra-intestinal autonomic testing abnormalities. Cancer was detected in three patients. Preimmunotherapy scintigraphy revealed slowed transit (19/21 evaluated; gastric, 11; small bowel, 12; colonic, 11); manometry studies were abnormal in 7/8. Postimmunotherapy, 17 (74%) had improvement (both symptomatic and scintigraphic, five; symptomatic alone, eight; scintigraphic alone, four). Nine responders re-evaluated had scintigraphic evidence of improvement. The majority of responders who were re-evaluated had improvement in autonomic testing (six of seven) or manometry (two of two). CONCLUSIONS & INFERENCES: This proof of principle study illustrates the importance of considering an autoimmune basis for idiopathic gastrointestinal dysmotility and supports the utility of a diagnostic trial of immunotherapy.

Dopamine agonist-triggered pathological behaviors: surveillance in the PD clinic reveals high frequencies.

BACKGROUND: Compulsive behaviors provoked by dopamine agonists often go undetected in clinical series, especially if not specifically inquired about. AIM: To determine the frequency of compulsive behaviors in a Parkinson's disease (PD) clinic where agonist-treated patients were routinely asked about such aberrant behaviors. METHODS: We utilized the Mayo Health Science Research database to ascertain all PD patients taking a dopamine agonist over a two year period (2007-2009). All were seen by a Mayo-Rochester Movement Disorders Staff specialist who routinely inquired about behavior compulsions. RESULTS: Of 321 PD patients taking an agonist, 69 (22%) experienced compulsive behaviors, and 50/321 (16%) were pathologic. However, when the analysis was restricted to patients taking agonist doses that were at least minimally therapeutic, pathological behaviors were documented in 24%. The subtypes were: gambling (25; 36%), hypersexuality (24; 35%), compulsive spending/shopping (18; 26%), binge eating (12; 17%), compulsive hobbying (8; 12%) and compulsive computer use (6; 9%). The vast majority of affected cases (94%) were concurrently taking carbidopa/levodopa. Among those with adequate followup, behaviors completely or partly resolved when the dopamine agonist dose was reduced or ceased. CONCLUSIONS: Dopamine agonist treatment of PD carries a substantial risk of pathological behaviors. These occurred in 16% of agonist-treated patients; however, when assessing patients whose dose was at least minimally in the therapeutic range, the frequency jumped to 24%. Pathological gambling and hypersexuality were most common. Carbidopa/levodopa therapy taken concurrently with a dopamine agonist appeared to be an important risk factor.

Sudomotor dysfunction in autoimmune autonomic ganglionopathy.

BACKGROUND: Autoimmune autonomic ganglionopathy is characterized by impairment of multiple autonomic domains of which sudomotor function is among the most common. Many patients with this disorder have difficulties with thermoregulation and anhidrosis. Our objective was to characterize the distribution and severity of sudomotor dysfunction in this disorder. METHODS: Sudomotor function was analyzed in a cohort of 21 patients with ganglionic alpha3 nicotinic acetylcholine receptor (nAChR) antibody positive autoimmune autonomic ganglionopathy. Standard measurements of sudomotor function were used including the Thermoregulatory Sweat Test and Quantitative Sudomotor Axon Reflex Test. RESULTS: The clinical presentation in all patients was characterized by widespread sudomotor dysfunction. Sudomotor impairment was predominantly postganglionic in 17 of the 21 patients studied. Higher ganglionic alpha3 nAChR antibody levels resulted in progressive postganglionic predominant dysfunction (postganglionic, r = 0.637, p = 0.002; mixed ganglionic, r = 0.709, p < 0.001). The pattern of anhidrosis on Thermoregulatory Sweat Testing was consistent with a ganglionopathy in the majority of patients (14 of 21) and a distal pattern in a minority of patients (8 of 21). These patterns of anhidrosis coupled with increasing postganglionic dysfunction in a proximal to distal pattern (foot > distal leg > proximal leg > forearm) indicate lesions at both the ganglia and distal axon of the postganglionic sudomotor sympathetic neuron. CONCLUSIONS: Our data characterize the unique sudomotor dysfunction in autoimmune autonomic ganglionopathy as widespread, predominantly postganglionic, and a result of lesions at both the ganglia and distal axon. This study provides important support to the hypothesis that this disorder represents a ganglionic neuropathy.

Efficacy of immunotherapy in seropositive and seronegative putative autoimmune autonomic ganglionopathy.

OBJECTIVE: To evaluate the efficacy of immunotherapy in the treatment of patients with seropositive and seronegative putative autoimmune autonomic ganglionopathy (AAG) using validated autonomic function tests and instruments. BACKGROUND: AAG is an immune-mediated disorder characterized by prominent and selective involvement of autonomic nerve fibers or ganglia. Treatment with i.v. immunoglobulin (IVIg) or plasma exchange (PE) has been reported to be effective in single case reports. METHODS: We studied six patients, four with seropositive and two with seronegative putative AAG, who underwent autonomic function tests and completed two validated questionnaires, to assess autonomic symptoms before and after immunomodulatory treatment. Patients were treated with standard doses of IVIg, PE, or immunosuppressants in a specific sequential therapy protocol depending on clinical response. RESULTS: Of the six patients (all women, mean ages 49.3 +/- 10.6 years), four patients were ganglionic (alpha3) AChR autoantibody positive and two were autoantibody negative. All patients showed clinical improvement after treatment. Sudomotor function assessed by quantitative sudomotor axon reflex test and thermoregulatory sweat test improved in four patients after treatment. CONCLUSIONS: Immunomodulatory treatment can be effective in both seropositive and seronegative putative autoimmune autonomic ganglionopathy. Plasma exchange or combined therapy with immunosuppressive agents should be considered in patients who do not benefit from i.v. immunoglobulin alone.