Faculty Bibliography

Involvement of the autonomic cardiac nervous system in early stages of amyotrophic lateral sclerosis (ALS) was evaluated in 40 patients. I-123-metaiodobenzylguanidine-single photon emission computed tomography (MIBG-SPECT) and heart rate variability (HRV) yielded information about sympathetic and parasympathetic innervation of the heart. MIBG-SPECT is a sensitive diagnostic method for demonstration of early cardiac sympathetic denervation. Both sympathetic and parasympathetic dysfunction was observed in 16 (40%) out of 40 patients. Mean cardiac MIBG uptake as demonstrated by the heart/mediastinum ratio was significantly reduced in all ALS patients in comparison with controls (P<0.01). The global MIBG-SPECT score was clearly abnormal in 29% and slightly abnormal in 22% of patients. HRV was diminished in 6 of 38 patients, 4 of whom having an abnormal MIBG-SPECT score as well. The presented results indicate that ALS patients with mild to moderate impairment may have evidence of postganglionic sympathetic adrenergic cardiac or cardiovagal denervation. To our knowledge, this is the first study indicating possible postganglionic sympathetic denervation in ALS. The original concept of ALS as an isolated degeneration of motor neurons seems to extend to a more widespread understanding of the disease which possibly represents different entities

The autonomic nervous system consists of two different components: the sympathetic and the parasympathetic nervous system, which are controlled by a central network in the brain and spinal cord. Therefore autonomic dysfunctions are caused by a variety of diseases of the CNS and PNS. Due to CNS diseases there are two general types of autonomic dysfunctions. Firstly deficiency syndromes caused by cell lesions and secondly pure dysfunctions without any structural lesions. Typical primary deficiency syndromes are MSA and Parkinson's disease; secondary deficiency syndromes are, for example, brain infarctions or syringomyelia. Typical examples of pure dysfunctions of the autonomic nervous system are side effects of drugs. Consecutive symptoms of an efferent autonomic denervation are pupillary dysfunction, trophic disturbances, anhidrosis and vasodysregulation; consecutive symptoms of an autonomic visceral denervation are cardioneuropathy, gastrointestinal disorders and urogenital disturbances. Diabetes mellitus is the most important etiology of autonomic peripheral neuropathy. $$:

This review article focuses on the functional anatomy of the central autonomic nervous system and the autonomic symptoms and dysfunctions occurring with epileptogenic activity involving areas of the central autonomic nervous system. Clinical experiences have demonstrated a close relation between epileptic and central autonomic activity. Autonomic symptoms are frequent signs of epileptic seizures and may cause dysfunctions in almost every organ system. Cardiorespiratory dysfunction has been described interictually. The increased frequency of sudden unexplained death in epilepsy patients may be related to disturbances in cardiac autonomic control. In contrast, electrical vagal stimulation reduces epileptogenic activity by influencing the central autonomic nervous system

Diabetic neuropathy is a mixed, but predominantly axonal neuropathy of all fiber types. Axonal damage accounts for fibrillations in needle electromyography (EMG). Nerve conduction studies show amplitude reduction of compound muscle action potentials and sensory nerve action potentials due to axonal damage. Peripheral nerve demyelination induces slight or moderate nerve conduction slowing. In early stages, distal foot muscles show fibrillations, sural nerve conduction is abnormal, peroneal nerve F-wave and H-reflex-latencies are prolonged. In advanced stages, EMG of proximal leg muscles or even arm muscles and upper extremity nerve conduction are abnormal. Diabetic radiculopathies and mononeuropathies are diagnosed by EMG. Mechanical ethiologies have to be ruled out by neuroimaging. Quantitative sensory testing (QST) is of high diagnostic value in diabetic neuropathy. Vibratory and thermal threshold evaluation unveil early neuropathy. Thermotesting is particularly valuable in the assessment of diabetic small fiber neuropathy and allows monitoring of the disease. $$:

Uniform criteria are necessary for the diagnosis and staging of diabetic neuropathy. In 1988 the San Antonio Consensus Conference on Diabetic Neuropathy recommended the assessment of five diagnostic categories: neuropathic symptoms, neuropathic deficits, pathologic nerve conduction studies, pathologic quantitative sensory examinations and pathologic quantitative autonomic examination. The 'Rochester Diabetic Neuropathy Study' (RDNS)-group recommended to base the diagnosis of diabetic neuropathy on pathologic findings in at least two of these five categories. We review present the minimal diagnostic criteria required to define abnormality for each of these categories. Clinical parameters as well as various scores, e.g. the Neuropathy Impairment Score, Neuropathy Dis ability Score, and Neuropathy Symptom Score are discussed. An easily applicable tool to stage polyneuropathy is the Erlangen Neuropathy Assessment Questionnaire. $$:

Dysfunction of autonomic nervous system affects up to 30% of patients with diabetes mellitus after 10 to 15 years. The autonomic neuropathy, especially cardiovascular autonomic neuropathy has a broad influence on the course and the prognosis of patients. Non-invasive cardiovascular reflex tests and tests of sudomotor control allow to diagnose autonomic dysfunction before the patients develop a symptomatic autonomic neuropathy. There is evidence that deterioration of autonomic dysfunction can be prevented and autonomic function even improves with good metabolic control e.g. by means of insulin infusion systems. This manuscript describes cardio-vascular and sudomotor function tests as well as two batteries of tests used for evaluation and classification of cardiovascular autonomic neuropathy. $$:

The additional occurring of entrapment syndromes in patients who suffer from diabetic neuropathy frequently causes diagnostic problems. The electrophysiological differentiation is often complicated. The following article gives a literature rewiew about the frequency of the combination of both diseases. Possible reasons for the frequent coincidence of these two diseases are explained. The electrophysiological techniques to differentiate whether a patient's symptoms are caused by a diabetic polyneuropathy or a carpal tunnel syndrome are shown. $$:

Up to now, treatment of diabetic polyneuropathy remains unsatisfactory. Nevertheless, new pathogenetic concepts about the possible reasons for the development of diabetic neuropathy create new therapeutic approaches to the disease. The following article reviews the therapeutic agents commonly used. Furthermore some new substances are reported which interfere in the pathogenetic pathway of diabetic neuropathy and might be beneficial for the patients suffering from this neuropathy in the future. $$: