Thoracoscopic Sympathectomy for Palmar Hyperhidrosis

AORN Journal, August, 2001 by Gloria M. Allen

Hyperhidrosis is excessive sweating beyond the physiological need. It usually affects the palms, axillae, and soles and may affect the face, groin, and legs. Symptoms usually appear at puberty and may cause psychological and social problems, as well as occupational and educational difficulties. Between 0.6% and 1% of the general population are affected by hyperhidrosis.(1)

People with palmar hyperhidrosis may be embarrassed to hold hands or be hesitant to shake hands because of having excessively wet palms, often feeling as if they must wipe their palms on their clothing first. People with palmar hyperhidrosis may have difficulty holding onto objects or tools or may have difficulty using computer keyboards, typewriters, or pens. Papers they handle may become wet, and metal objects that they use repeatedly may become rusty. Individuals with palmar hyperhidrosis may find it difficult to play a musical instrument or perform a job requiring the wearing of gloves (eg, food handler, perioperative nurse).

Patients with palmar hyperhidrosis may find that it aggravates eczematous dermatitis, and they may have a predisposition to bacterial and fungal infections. As a result, these people may become withdrawn socially and suffer from low self-esteem. They even may develop psychiatric problems, such as social anxiety disorders.

PHYSIOLOGY OF SWEATING

Sweating is a physiological response to body overheating. It is controlled by the heat regulatory center in the hypothalamus. As the temperature of the environment rises, the body is cooled by vasodilatation of the cutaneous blood vessels and the production of sweat. The sweat then evaporates from the surface of the skin and cools the body.(2)

Sweat glands are tubular structures consisting of a coiled portion deep within the dermis that secretes sweat and a duct through which the sweat travels to the skin. Cholinergic sympathetic nerve fibers on or near the glandular cells elicit the secretion of sweat.

The secretory portion of the gland secretes a fluid called precursor secretion. Concentrations of the constituents of this fluid are modified as the fluid travels through the duct to the pore. When sweat glands are stimulated normally, the precursor secretion passes slowly through the duct where most of the sodium and chloride content is reabsorbed. The concentration of sodium and chloride can fall as low as 5 mEq per liter. This reduces the fluid's osmotic pressure, and most of the water is reabsorbed, thus concentrating other ions in the fluid.

In normal sweating, urea, lactic acid, and potassium ions are very concentrated. When the sweat glands are stimulated strongly by the sympathetic nervous system, large amounts of precursor secretion are formed. Sweat flows so rapidly through the duct that little of the water and slightly more than one-half of the sodium and chloride are reabsorbed, leaving sodium and chloride concentrations as high as 50 to 60 mEq per liter. In these situations, a large loss of sodium chloride and water can occur.(3)

The human body contains two types of sweat glands--apocrine and eccrine. Their location and characteristics differ slightly.

Apocrine sweat glands. The apocrine sweat glands are confined to the axillae, areolas of the nipples, the anogenital area, and the external auditory meatus. They are simple, coiled tubes and are 10 times larger than eccrine glands. The sweat from these glands is milky, contains fat and cholesterol, and can have a strong odor. The apocrine glands begin to function at puberty.

Eccrine sweat glands. The eccrine glands are present on the entire surface of the body but are most numerous on the palms, soles of the feet, face, axillae, and, to a lesser degree, the back and chest. They are coiled tubular glands that open onto the skin through pores. These sweat glands have a rich blood supply and are innervated by the sympathetic nervous system (Figure 1). Nerves stimulate the glands to secrete a plasma-like fluid that is hypotonic (ie, 0.3% to 0.5% sodium chloride) and contains small amounts of potassium, lactic acid, glucose, and urea. Myoepithelial cells, through their contraction, aid in the expulsion of sweat. Acetylcholine and other cholinergic agents increase sweating. Atropine and anticholinergic agents inhibit sweating.(4)

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CAUSES OF HYPERHIDROSIS

There are many causes of hyperhidrosis. It can be caused by

* emotional factors,

* a warm environment,

* exercise,

* warm clothing,

* medical conditions (eg, fever, thyrotoxicosis, diabetes mellitus, hypoglycemia, gigantism, and acromegaly, pheochromocytoma, cardiovascular disorders, Hodgkin's disease),

* medications,

* toxins,

* substance abuse,

* respiratory failure,

* intrathoracic or hypothalamic lesions,

* carcinoid tumors,

* spinal cord injuries, and

* familial dysautonomia (eg, Riley-Day syndrome--an inherited congenital disease occurring mainly in children of Ashkenazic Jewish decent and characterized by a decrease in the number of small unmyelinated autonomic and peripheral fibers that carry pain, temperature, and taste sensations; Nail-patella syndrome--an inherited multisystem disorder characterized by dystrophic nails, hypoplastic or absent patellae, and renal disease).