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Comprehensive Physiology Jan 2015The autonomic nervous system influences numerous ocular functions. It does this by way of parasympathetic innervation from postganglionic fibers that originate from... (Review)
Review
The autonomic nervous system influences numerous ocular functions. It does this by way of parasympathetic innervation from postganglionic fibers that originate from neurons in the ciliary and pterygopalatine ganglia, and by way of sympathetic innervation from postganglionic fibers that originate from neurons in the superior cervical ganglion. Ciliary ganglion neurons project to the ciliary body and the sphincter pupillae muscle of the iris to control ocular accommodation and pupil constriction, respectively. Superior cervical ganglion neurons project to the dilator pupillae muscle of the iris to control pupil dilation. Ocular blood flow is controlled both via direct autonomic influences on the vasculature of the optic nerve, choroid, ciliary body, and iris, as well as via indirect influences on retinal blood flow. In mammals, this vasculature is innervated by vasodilatory fibers from the pterygopalatine ganglion, and by vasoconstrictive fibers from the superior cervical ganglion. Intraocular pressure is regulated primarily through the balance of aqueous humor formation and outflow. Autonomic regulation of ciliary body blood vessels and the ciliary epithelium is an important determinant of aqueous humor formation; autonomic regulation of the trabecular meshwork and episcleral blood vessels is an important determinant of aqueous humor outflow. These tissues are all innervated by fibers from the pterygopalatine and superior cervical ganglia. In addition to these classical autonomic pathways, trigeminal sensory fibers exert local, intrinsic influences on many of these regions of the eye, as well as on some neurons within the ciliary and pterygopalatine ganglia.
Topics: Accommodation, Ocular; Animals; Autonomic Nervous System; Eye; Humans; Intraocular Pressure; Neural Pathways; Pupil; Reflex; Regional Blood Flow; Trigeminal Nerve
PubMed: 25589275
DOI: 10.1002/cphy.c140014 -
Otolaryngologic Clinics of North America Apr 2016Frey syndrome is a common sequela of parotidectomy, and although it is not frequently manifested clinically, it can cause significant morbidity for those affected. Frey... (Review)
Review
Frey syndrome is a common sequela of parotidectomy, and although it is not frequently manifested clinically, it can cause significant morbidity for those affected. Frey syndrome results from synkinetic autonomic reinnervation by transected postganglionic parasympathetic nerve fiber within the parotid gland to the overlying sweat glands of the skin. Many surgical techniques have been proposed to prevent the development of Frey syndrome. For those who develop clinical symptoms of Frey syndrome, objective testing can be performed with a Minor starch-iodine test. Some of the current methods to prevent and treat symptomatic Frey syndrome are reviewed.
Topics: Botulinum Toxins, Type A; Humans; Parotid Gland; Postoperative Complications; Sweat Glands; Sweating, Gustatory
PubMed: 26902982
DOI: 10.1016/j.otc.2015.10.010 -
Current Neurology and Neuroscience... Dec 2022Autonomic neuropathies are a complex group of disorders and result in diverse clinical manifestations that affect the cardiovascular, gastrointestinal, urogenital, and... (Review)
Review
PURPOSE OF REVIEW
Autonomic neuropathies are a complex group of disorders and result in diverse clinical manifestations that affect the cardiovascular, gastrointestinal, urogenital, and sudomotor systems. We focus this review on the diagnosis and treatment of peripheral autonomic neuropathies. We summarize the diagnostic tools and current treatment options that will help the clinician care for individuals with peripheral autonomic neuropathies.
RECENT FINDINGS
Autonomic neuropathies occur often in conjunction with somatic neuropathies but they can also occur in isolation. The autonomic reflex screen is a validated tool to assess sympathetic postganglionic sudomotor, cardiovascular sympathetic noradrenergic, and cardiac parasympathetic (i.e., cardiovagal) function. Initial laboratory evaluation for autonomic neuropathies includes fasting glucose or oral glucose tolerance test, thyroid function tests, kidney function tests, vitamin-B12, serum, and urine protein electrophoresis with immunofixation. Other laboratory tests should be guided by the clinical context. Reduced intraepidermal nerve density on skin biopsy is a finding, not a diagnosis. Skin biopsy can be helpful in selected individuals for the diagnosis of disorders affecting small nerve fibers; however, we strongly discourage the use of skin biopsy without clinical-physiological correlation. Ambulatory blood pressure monitoring may lead to early identification of patients with cardiovascular autonomic neuropathy in the primary care setting. Disease-modifying therapies should be used when available in combination with nonpharmacological management and symptomatic pharmacologic therapies. Autonomic function testing can guide the therapeutic decisions and document improvement with treatment. A systematic approach guided by the autonomic history and standardized autonomic function testing may help clinicians when identifying and/or counseling patients with autonomic neuropathies. Treatment should be individualized and disease-modifying therapies should be used when available.
Topics: Humans; Autonomic Nervous System Diseases; Blood Pressure Monitoring, Ambulatory; Peripheral Nervous System Diseases; Autonomic Nervous System; Norepinephrine; Diabetic Neuropathies
PubMed: 36376534
DOI: 10.1007/s11910-022-01240-4 -
Neurotherapeutics : the Journal of the... Jan 2016The best-known peripheral neuropathies are those affecting the large, myelinated motor and sensory fibers. These have well-established immunological causes and... (Review)
Review
The best-known peripheral neuropathies are those affecting the large, myelinated motor and sensory fibers. These have well-established immunological causes and therapies. Far less is known about the somatic and autonomic "small fibers"; the unmyelinated C-fibers, thinly myelinated A-deltas, and postganglionic sympathetics. The small fibers sense pain and itch, innervate internal organs and tissues, and modulate the inflammatory and immune responses. Symptoms of small-fiber neuropathy include chronic pain and itch, sensory impairment, edema, and skin color, temperature, and sweating changes. Small-fiber polyneuropathy (SFPN) also causes cardiovascular, gastrointestinal, and urological symptoms, the neurologic origin of which often remains unrecognized. Routine electrodiagnostic study does not detect SFPN, so skin biopsies immunolabeled to reveal axons are recommended for diagnostic confirmation. Preliminary evidence suggests that dysimmunity causes some cases of small-fiber neuropathy. Several autoimmune diseases, including Sjögren and celiac, are associated with painful small-fiber ganglionopathy and distal axonopathy, and some patients with "idiopathic" SFPN have evidence of organ-specific dysimmunity, including serological markers. Dysimmune SFPN first came into focus in children and teenagers as they lack other risk factors, for example diabetes or toxic exposures. In them, the rudimentary evidence suggests humoral rather than cellular mechanisms and complement consumption. Preliminary evidence supports efficacy of corticosteroids and immunoglobulins in carefully selected children and adult patients. This paper reviews the evidence of immune causality and the limited data regarding immunotherapy for small-fiber-predominant ganglionitis, regional neuropathy (complex regional pain syndrome), and distal SFPN. These demonstrate the need to develop case definitions and outcome metrics to improve diagnosis, enable prospective trials, and dissect the mechanisms of small-fiber neuropathy.
Topics: Complex Regional Pain Syndromes; Erythromelalgia; Ganglia, Sensory; Humans; Immunotherapy; Peripheral Nervous System Diseases
PubMed: 26526686
DOI: 10.1007/s13311-015-0395-1