Istituti di Ricovero e Cura a Carattere Scientifico

Clinical Challenges in Primary Erythromelalgia: a Real-Life Experience from a Single Center and a Diagnostic-Therapeutic Flow-Chart Proposal.

Primary erythromelalgia (EM) is a rare clinical syndrome characterized by recurrent erythema, burning pain and warmth of the extremities. The symptoms greatly compromise the patients' quality of life leading to severe disability. SCN9A mutations can be the cause of the disease. Dermatologists are often the specialists these patients turn to for assistance. To describe the demographic and clinical characteristics of patients with primary EM, to assess the presence and mutation types in the SCN9A gene, to evaluate the effectiveness of several therapeutic approaches, and to propose a diagnostic algorithm with therapeutic implications. A monocentric retrospective study using the database of patients with a discharge diagnosis of primary EM of our Center. Demographic, clinical, instrumental and laboratory data of patients were reviewed. Eleven female patients (age range 16 to 57) were selected. All patients were affected in both the lower and upper extremities. Follow-up ranged from 2 to 9 years. Four patients had four different heterozygous variants of the SCN9A gene. Two patients, although genetically negative, had a suggestive family history. A variety of medications were tried in all our patients to alleviate symptoms, but their efficacy was variable, partial and/or transitory. The most effective therapies were antihistamines, venlafaxine, and mexiletine. The diagnosis and treatment of EM remain challenging. Patients with this condition display a wide spectrum of clinical manifestations and severity, as well as a paucity of resources and structures to support them. Mutations in the SCN9A gene are not always detected.

Secondary erythromelalgia: a tryptophan dietary supplement-induced case associated with elevated 5-hydroxyindoleacetic acid (5HIAA) urinary levels.

Microneurographic recording from unmyelinated nerve fibers in neurological disorders: an update.

Microneurography is a unique neurophysiological technique allowing direct recording of unmyelinated postganglionic sympathetic or afferent nociceptive fibers by tungsten needles inserted into a peripheral nerve fascicle. In recent years, microneurography has been used to ascertain autonomic impairments in central neurological disorders such as sleep disorders, Parkinson's disease, amyotrophic lateral sclerosis, or vasovagal syncope. Abnormal resting muscle sympathetic nerve activity (MSNA) and skin sympathetic nerve activity (SSNA) or the abnormal sympathetic response to arousal have been described in these disorders, thereby clarifying important pathophysiological aspects of the underlying impairment. In addition, microneurography was also recently used to demonstrate absent or decreased sympathetic outflow in diseases affecting the peripheral nervous system such as Ross syndrome, pure autonomic failure, and small-fiber neuropathy. Microneurography has also been used to study nociceptor outflow in pain disorders affecting the peripheral nervous system such as small-fiber neuropathy, diabetic neuropathy, erythromelalgia, complex regional pain syndrome, and fibromyalgia. In these disorders, microneurography mainly documented mechano-insensitive C-nociceptor hyperexcitability that might account for the ongoing pain.