Autonomic dysfunction

Autonomic Dysfunction
Clinical Manifestations: ANS disorders: due to-- central nervous system (CNS) causes Peripheral nervous system (PNS) causes Signs/Symptoms: due to interruption of reflex arc Site of interruption: afferent limb CNS processing center efferent limb Examples: posterior fossa tumors: medullary lesions may cause -- impaired blood-pressure responses to postural change (orthostatic hypotension) Lesions of vasomotor nerve fibers to blood vessels (e.g. diabetes or spinal cord disease) Lesions to afferent connections (e.g. Guillain-Barre syndrome) Segmental disorders (focal deficits): in spinal cord disease reflex sympathetic dystrophy Horner's syndrome Autonomic Dysfunction: symptoms-- Organ dependent Impotence-- first sign of autonomic failure-- sequence lost of spontaneous early morning erection loss of nocturnal penile tumescence total impotence Bladder dysfunction: occurs early both in men and women (especially with CNS involvement) Brain/spinal cord disease: above the level of the lumbar spine(upper motor neuron) disease: urinary frequency/small bladder volumes incontinence Autonomic fiber disease to the bladder (lower motor neuron disease) or sensory denervation: large bladder volumes urinary frequency overflow incontinence Gastrointestinal Dysfunction: severe constipation typically Exception -- diabetes diarrhea-- cause rapid transit of contents uncoordinated small bowel activity osmotic diarrhea (bacterial overgrowth -- small bowel stasis Decreased salvation (glandular effects) Eye irritation: -- reduced lacrimation Orthostatic Hypotension: most disabling feature of autonomic dysfunction Definition: postural decrease of at least 20 mm Hg in systolic or 10 mm Hg in diastolic blood pressure sustained for least 3 minutes (to differentiate between autonomic dysfunction and sluggish baroreceptor reflex response {common in the elderly}) Symptoms of postural hypotension: dimming or loss of vision light headedness diaphoresis impaired hearing pallor/weakness syncope