Diagnosis and management of diabetic autonomic neuropathy

Autonomic neuropathy affects every system in the body including the eye, cardiovascular, respiratory, and gastrointestinal and neurovascular systems. The diagnosis confers an attenuated life expectancy, but much can be done to alleviate symptoms and to address the underlying disorder.

Autonomic dysfunction in peripheral nerve disease

Autonomic neuropathies are inherited or acquired neuropathies in which autonomic nerve fibers are selectively or disproportionately affected. Generally, sympathetic and parasympathetic fibers are both affected but there are exceptions. Acquired cases can be autoimmune; due to diabetes, amyloidosis, drugs, or toxins; or idiopathic. Autoimmune autonomic neuropathy is often subacute, sometimes associated with a neoplasm, and associated with high titers of antibody to ganglionic nicotinic acetylcholine receptor in about half of the severe cases. The molecular basis of inherited autonomic neuropathies is better known, including recent identification of the loci and genes of hereditary sensory and autonomic neuropathies types I, III, and IV. The inherited amyloid neuropathies are due to mutations of three proteins: transthyretin, apolipoprotein A1, and gelsolin. Non-invasive autonomic testing complements clinical and electrophysiological characterization of the autonomic neuropathies.

[Efficacy of acupressure therapy in combined treatment of psycho-autonomic neurotic disorders in children]

The aim of the study was to evaluate the efficacy of acupuncture in combined treatment of psychoautonomic neurotic disorders in children. 163 children, mean age 12.5 years, were included in the study. Autonomic dysfunction score, clinoorthostatic test, sinocarotid test and heart rate variability analysis were used to assess the efficacy of different therapeutic strategies applied: complex (acupuncture + conventional drug treatment)--group 1; acupuncture treatment--group 2, and conventional drug treatment--group 3. After 2 months of treatment, a reduction of autonomic dysfunction score and an increase of percentage of patients with normal clinoorthostatic and sinocarotid tests were revealed in all the groups, being most evident in group 1. Heart rate spectral variability changed in patients given acupuncture treatment (groups 1 and 2). Relative augmentation of sympathetic activity was observed in patients with initial vagotonia, while those with initial symphaticotonia exhibited a relative parasympathetic activity increase. Thus, acupuncture exerts beneficial effects on functioning of autonomic nervous system. The method may be used either independently, or in addition to conventional drug treatment of psychoautonomic neurotic disorders in children.

Autonomic Failure in Neurodegenerative Disorders

Autonomic failure with orthostatic and postprandial hypotension, bowel and bladder disturbances, and sexual dysfunction are frequent, disabling features in patients with the three most prevalent neurodegenerative movement disorders: Parkinson's disease (PD), dementia with Lewy bodies and multiple system atrophy (MSA), and the related neurodegenerative Lewy-body disorder characterized by isolated severe autonomic failure (pure autonomic failure, PAF). All of these disorders have in common the presence of alpha-synuclein in the cytoplasmic precipitates found in neurons in Lewy body disorders or glia in MSA. Autonomic failure with disabling orthostatic hypotension is the clinical hallmark of PAF. It may also be the initial presentation of MSA, making diagnosis difficult. Within a few years, however, MSA patients develop movement disorders, which are differentiated from PD by the paucity of unilateral resting tremor, the lack of response to levodopa, and their rapidly progressive nature, resulting in disability and death in 7 to 8 years. Moderately effective treatment is available for autonomic symptoms, but management of movement disorders remains unsuccessful. Discoveries relevant to physiology and common pathological conditions were initially made in patients with autonomic failure. Meals induce profound hypotension in these patients. Conversely, commonly used nasal decongestants can produce substantial pressor effects. Even 500 mL of water can increase blood pressure by a previously unrecognized sympathetic reflex. Residual sympathetic tone is able to induce sustained supine hypertension in MSA, because it is resolved after ganglionic blockade. These phenomena were not previously recognized because of the buffering capacity of the baroreflex, but were unmasked in autonomic failure patients.

Evaluation and Treatment of Autonomic Disorders of the Gastrointestinal Tract

Despite the extensive impact of autonomic function on the gastrointestinal system, there is little understanding of the mechanisms by which specific autonomic abnormalities translate into particular gastrointestinal complaints. Three logical alternatives include: (1) the underlying disorder affects the autonomic and gastrointestinal systems independently; (2) autonomic dysfunction alters gastrointestinal processing directly; (3) gastrointestinal manifestations arise as a delayed, indirect consequence of autonomic dysfunction. The major gastrointestinal manifestations of dysautonomia include esophageal dysmotility such as achalasia, gastroparesis, and small bowel bacterial overgrowth in the upper tract. Lower tract disorders include diarrhea, fecal incontinence, and constipation. Sorting through the varied causes of these disorders requires a careful history and examination in each patient. Supportive diagnostic studies may include radionuclide imaging, motility examination, and electrogastrography. Autonomic studies can (1) distinguish a purely enteric from a more generalized dysautonomia; (2) provide surrogate information about motility; (3) differentiate primary (e.g., multiple system atrophy) from secondary (e.g., irritable bowel syndrome) dysautonomias as the etiology of gastrointestinal symptoms. Several new strategies are available for the treatment of gastroparesis, constipation, irritable bowel, and sphincteric incontinence.

Evaluation and Treatment of Autonomic Disorders of the Urogenital System

Autonomic pathways are important in the regulation of both lower urinary tract and sexual function, and their interruption in neurological pathologies predictably results in variable urogenital dysfunction, depending mainly on the level of the lesion. A normal neurological examination of a patient with urogenital complaints should exclude an underlying neurological pathology, and the neurologist should become involved in the management of symptoms. Electromyography can be of value in the diagnosis and management of cauda equina lesions and multiple system atrophy, but neurophysiological investigations are of no importance in the diagnosis of neurogenic sexual dysfunction. Urodynamic studies have proven helpful in determining the type and management of lower urinary tract dysfunction. Oral anticholinergics usually combined with clean intermittent catheterizations are the first-line treatment options for neurogenic lower urinary tract dysfunction, with intravesical treatments emerging as the main alternative in intractable incontinence. The availability of effective oral phosphodiesterase inhibitors has revolutionized the management of erectile dysfunction, but treatment of ejaculatory and orgasmic disorders as well as of female sexual dysfunction still remains problematic.

[Trigemino-autonomic headache syndromes]

This review describes the characteristics of some rare severe primary headache syndromes without any structural lesions, which are summarized as the trigemino-autonomic headaches. Pain in these syndromes is associated with autonomic symptoms such as conjunctival injection, lacrimation, rhinorrhoe, ptosis or eyelid edema. This article summarizes the diagnostics, epidemiology and therapy of these conditions.

[State of prostaglandin system in adolescents with the hypotensive type vegetovascular dysfunction during hyperbaric oxygenation]

As many as 185 adolescents with hypotensive type vegetovascular dysfunction who ranged between 11 to 14 years old were studied for impact of a conventional treatment and that involving the use of hyperbaric oxygenation on the blood content of prostaglandins E2 and F2 alpha. The control group was 69 essentially healthy adolescents of the same age. Before the start of the treatment those persons presenting with hypotensive type vegetovascular dysfunction revealed an increase in prostaglandins E2 and decline in prostaglandins F2 alpha. There was no change in this trend with the conventional therapy. Owing to hyperbaric oxygenation, the above classes prostaglandins recovered their normal balance, which fact promoted reversal of clinical symptoms of the condition. The results secured permit recommending hyperbaric oxygenation as an efficient mode of treatment of hypotensive type vegetovascular dysfunction in juvenile subjects.

Autonomic neuropathies

PURPOSE OF REVIEW

To update recent advances in the pathogenesis, pathophysiology and treatment of some autonomic neuropathies.

RECENT FINDINGS

When evaluating a patient with subacute autonomic neuropathy, certain autoantibodies are important in diagnosis and may influence management. Ganglionic antibody may be pathogenetically important while the paraneoplastic antibodies alert the clinician to the presence of an occult neoplasm. Autonomic failure is an integral component of diabetic neuropathy. Sildenafil is safe and efficacious in treating erectile dysfunction in diabetic patients. Sympathetic cardiac hyperinnervation can occur concurrently with denervation in diabetic neuropathy The gene mutations for hereditary sensory and autonomic neuropathies I, III, and IV are now known and there is clear unmyelinated fiber loss. Additional options for treatment of orthostatic hypotension include erythropoietin and, surprisingly, water. Botulinum toxin is efficacious, at least for a time, for the treatment of palmar and axillary hyperhidrosis.

SUMMARY

Ganglionic antibody likely mediates autoimmune autonomic neuropathy. Sympathetic cardiac hyperinnervation can occur and could potentially cause arrhythmia and sudden death. Knowledge of gene mutations of hereditary sensory and autonomic neuropathies I, III and IV could lead to more secure diagnosis of the disorders. Effective treatment of essential hyperhidrosis with botulinum toxin injection has been demonstrated. It might be possible to improve treatment of orthostatic hypotension acutely with water imbibation and chronically with erythropoieting.

Effect of local application of cold or heat for relief of pricking pain

The present study was designed to determine the effect of the application of cold or heat on the sensation of pricking pain based on autonomic responses. Electrical stimulation was applied to the antebrachium or brachium of subjects as an artificial pricking pain, and skin blood flow (BF) and skin conductance level (SCL) at the fingertip were measured. Pain sensation was evaluated using the visual analog scale. Pain stimulation produced a significant increase in SCL and a significant decrease in BF at both the antebrachium and brachium. Application of cold to the stimulation site using an ice-water pack reduced BF and SCL responses and pain sensation. Application of heat using a hot water bottle caused a significant increase in pain sensation and enhancement of BF and SCL responses. These results suggest that application of cold promotes relief of pricking pain sensation and suppression of autonomic responses, and that application of heat has no such effect. It is important that nurses ascertain the type of pain or source of pain and take proper measures for its relief.

[Autonomic neuropathy in diabetic patients. Part II. Diagnosis and treatment]

Many diabetic patients have demonstrable abnormalities of autonomic function without any evidence of clinical disease. Tests of autonomic function are assumed to be a measure of "neurological" state and may be important methods of assessing therapy of diabetic complications.

Peripartum management of a patient with dopamine beta-hydroxylase deficiency, a rare congenital cause of dysautonomia

We present the first reported case involving the peripartum anaesthetic management of dopamine beta-hydroxylase deficiency in a 22-year-old primigravida with high-grade placenta praevia. Elective caesarean section was performed at 36 weeks gestation with a combined spinal-epidural regional anaesthetic technique. Extensive preparation was undertaken to manage the consequences of obstetric haemorrhage and consideration given to potential pharmacological sensitivities suspected to exist in patients with this rare disorder affecting sympathetic nervous system function. An uncomplicated caesarean section was performed from which the patient recovered well to be discharged home with a healthy baby.

Resolution of diabetic autonomic neuropathy

Many consider diabetic autonomic neuropathy to be an irreversible complication of diabetes of long duration. Three patients developed symptoms of autonomic neuropathy which subsequently resolved. Their autonomic neuropathy was not associated with long duration of diabetes, but with weight loss. Each had marked weight loss and resolution occurred on regaining remembered premorbid weight. A woman aged 20 was admitted with anorexia nervosa (weight loss 6 kg). She complained of feeling bloated. Gastroenterological investigations showed delayed gastric emptying. RR ratio (respiration and standing) was abnormal. Resolution occurred after two years. A male aged 18 developed diabetic symptoms, which were overlooked. Twelve months later he presented underweight and ketonuric; insulin treatment was started but within one month he became impotent. Resolution occurred after 18 months. An 80 year old man presented after six months trial of diet and sulphonylurea therapy. He was underweight, had ketonuria, and such muscle loss that he was unable to sit unaided. Insulin treatment was started. He developed severe symptomatic postural hypotension. This resolved six months later by which time he had regained his normal weight. These cases illustrated symptomatic autonomic neuropathy occurring in relation to weight loss with resolution on recovery of normal weight, a temporal pattern mimicking that of acute cachectic painful neuropathy. Treatment of autonomic neuropathy should be like that of cachectic neuropathy, that is with an expectation of recovery and should include strategies to regain premorbid weight and achieve glycaemic control.

Haemodynamic responses during head-up tilt and tilt reversal in two groups with chronic autonomic failure: pure autonomic failure and multiple system atrophy

Continuous haemodynamic responses to head-up tilt (HUT) and its reversal were studied in 21 subjects with sympathetic denervation due to primary chronic autonomic failure; 10 had pure autonomic failure (PAF; peripheral failure) and 11 had multiple system atrophy (MSA; central failure); 8 healthy subjects (controls) also were studied. Supine systolic, diastolic and mean arterial pressure (MAP) and total peripheral resistance (TPR) were highest in PAF. The MAP response to HUT and tilt reversal were different between groups. After HUT, MAP increased in controls (12+/-4 mmHg), but decreased in PAF and MSA (41+/-4 & 19+/-4 mmHg respectively); the fall in PAF was greater than in MSA. With tilt reversal, MAP returned promptly, but not entirely to pretilt levels in controls, with small (insignificant) overshoots in MSA and PAF. The TPR response to HUT and tilt reversal was different between groups. After HUT, TPR increased in controls (0.31+/-0.04 PRU), decreased in PAF (0.23+/-0.1 PRU) and was unchanged in MSA. With tilt reversal, TPR remained elevated (15 %) above baseline in the controls and rose in PAF (13 %) with no change in MSA. There were no differences in supine heart rate (HR), stroke volume (SV) or cardiac output (CO) between the three groups; HR, SV or CO responses to HUT or tilt reversal also did not differ between the groups. Thus, after HUT, MAP decreased, with greater hypotension induced in PAF than MSA. Since CO did not differ between groups, the decrease in TPR appears to account for the greater fall in BP in PAF than in MSA. The elevated TPR at rest pre-tilt and after tilt reversal probably contributed to supine hypertension in PAF. These haemodynamic observations may aid therapeutic strategies to reduce orthostatic hypotension and prevent supine hypertension.

Management of dysautonomia in fibromyalgia

The realization of dysautonomia in FM has opened the possibility for new and different therapeutic interventions. Much more research is needed to better define the role of ANS in the pathogenesis of FM. If this research supports current hypotheses, therapeutic trials with disciplines and substances intended to correct autonomic dysfunction will be indicated.

Ion channel-directed therapies in autonomic neurons: a view from the bench

Voltage-gated and ligand-gated ion channels have been mapped in autonomic neurons. Furthermore, clinical pathology is associated with altered function of certain ion channels in autonomic neurons, most by channel-binding auto-antibodies. Medications that are directed to ion channels account for a major pharmaceutical market segment. Ion channel-directed drug therapies may be used to treat autonomic dysfunction. In turn, drug therapies for non-autonomic disorders (e. g., for cardiac disorders) often have unwanted effects on autonomic regulation. Within the last decade, we have witnessed an explosion of information about the molecular details of ion channel biology. Knowledge of ion channel molecular biology paired with advances in screening technologies and gene therapy may be useful for developing new ion channel-directed therapies.

Water drinking as a treatment for orthostatic syndromes

PURPOSE

Water drinking increases blood pressure in a substantial proportion of patients who have severe orthostatic hypotension due to autonomic failure. We tested the hypothesis that water drinking can be used as a practical treatment for patients with orthostatic and postprandial hypotension, as well as those with orthostatic tachycardia.

SUBJECTS AND METHODS

We studied the effect of drinking water on seated and standing blood pressure and heart rate in 11 patients who had severe orthostatic hypotension due to autonomic failure and in 9 patients who had orthostatic tachycardia due to idiopathic orthostatic intolerance. We also tested the effect of water drinking on postprandial hypotension in 7 patients who had autonomic failure. Patients drank 480 mL of tap water at room temperature in less than 5 minutes.

RESULTS

In patients with autonomic failure, mean (+/- SD) blood pressure after 1 minute of standing was 83 +/- 6/53 +/- 3.4 mm Hg at baseline, which increased to 114 +/- 30/66 +/- 18 mm Hg (P <0.01) 35 minutes after drinking. After a meal, blood pressure decreased by 43 +/- 36/20 +/- 13 mm Hg without water drinking, compared with 22 +/- 10/12 +/- 5 mm Hg with drinking (P <0.001). In patients with idiopathic orthostatic intolerance, water drinking attenuated orthostatic tachycardia (123 +/- 23 beats per minute) at baseline to 108 +/- 21 beats per minute after water drinking ( P <0.001).

CONCLUSION

Water drinking elicits a rapid pressor response in patients with autonomic failure and can be used to treat orthostatic and postprandial hypotension. Water drinking moderately reduces orthostatic tachycardia in patients with idiopathic orthostatic intolerance. Thus, water drinking may serve as an adjunctive treatment in patients with impaired orthostatic tolerance.

[Autonomic disorders in idiopathic Parkinson syndrome: diagnostic relevance and therapeutic possibilities]

Involvement of the autonomic nervous system in Parkinson's disease (PD) demonstrates the multiple system character of this disease exceeding the extrapyramidal system. Forty to sixty percent of patients with PD suffer from symptoms of autonomic failure impairing their quality of life. Autonomic failure in PD is caused by damage to the postganglionic part of the autonomic nervous system. Scintigraphy with radiolabeled metaiodobenzylguanidin (MIBG) provides evidence of autonomic involvement at an early stage of the disease and enables an early differential diagnosis of PD versus other neurodegenerative disorders. Sensitivity to identify PD versus multiple system atrophy is 89.7%, specificity in 94.6%. Orthostatic hypotension is a frequently overlooked symptom in PD. Diagnosis and cause of orthostatic hypotension can be identified with clinical methods. There are effective physical and pharmacological treatments to improve symptoms.