الفهرس 
ThermotherapyOnly 14 pages are availabe for public view
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Abstract
Thermotherapy is the therapeutic application of heat or cold to treat a disease and relieve its associated symptoms whether alone or as an adjuvant with various established treatment modalities. Thermotherapy incorporating both of heat and cold has been used as a medicinal and healing modality throughout human history. Today, thermotherapy is being studied in the treatment of many diseases in most branches of medicine especially in dermatology.
Heat therapy is a type of treatment in which body tissue is exposed to high temperatures in order to achieve the desired therapeutic outcomes ranging from healing and repair in mild temperature elevation up to cellular necrosis and destruction of diseased or undesirable tissue in high doses. Heat can be delivered by a variety of ways; some are simple as hot water bath, water jackets, benzene pocket warmers, disposable chemical heat packs, electric heating pads and for larger areas electric bed warmers in addition to hot water bottles. However, there are more sophisticated devices facilitate more uniform, constant and intense heat such as infrared emitting devices including water-filtered infrared-A device and infrared lasers particularly the CO2 laser and Nd:YAG laser, microwaves, radiofrequency in addition to ultrasound devices.
Because of its temporary side effects such as hyperpigmentation of the treated area and occasional superficial burns with more intense delivery systems such as infrared delivery devices, heat appears to be well tolerated therapy and achieve an ever-increasing number of clinical indications in modern medicine, especially in dermatology.
Application of heat below the level of 41°C has been mainly used in physiotherapy for treatment of bursitis, degenerative arthropathy, joint capsule contractures and for relieving of pain, muscle spasm, inflammation and edema. A higher level up to 45°C has common applications in oncology for cancer treatment as it was found to be effective in damaging the tumor cells by making them more sensitive to the other types of cancer treatments as radiation therapy or chemotherapy.
Beyond the level of 45°C, catabolism and irreversible tissue damage will occur. Heat therapy with temperatures ranging from 45°C to 50°C results in limited tissue ablation. As a cell’s internal temperature reaches between 50° C and 100°C; macromolecules, proteins and DNA molecules become denatured and this lead to significant tissue ablation. Cell death results from coagulative necrosis, which occurs above 50°C after two minutes. Thermal ablation was reported in oncology for cancer treatment in many organs such as; liver, kidney, adrenal gland, breast and prostate, in urology for treatment of lower urinary tract symptoms due to benign prostatic hypertrophy and in cardiology for treatment of arrhythmia by targeting and destroying cardiac tissue that is the source of the arrhythmia. Heat therapy has been also played an increasingly important role in otolaryngology and ophthalmic surgery especially with Nd:YAG and CO2 lasers as an energy sources.
Promising results from recent clinical trials indicate the effectiveness of heat therapy in the treatment of wide variety of dermatologic lesions whether malignant as basal cell carcinoma or benign as trichoepithelioma, syringoma, hypertrophic scar and keloid, and steatocystoma multiplex. Other dermatologic indications of heat therapy include; hyperhidrosis, metabolic skin disorder as xanthelasma, acantholytic diseases such as benign familial pemphigus, inflammatory lesions including hidradenitis suppurativa and rosacea in addition to vascular lesions as telagiectatic leg veins, lymphangioma circumscriptum and venous malformation. Additionally, heat therapy has shown great advancements in cosmetic indications that involve rhinophyma, striae distensae, scar revision, skin tightening and reduction of wrinkles, and the list is growing daily.
Although thermotherapy implies the use of heat it also includes the use of cold as it is also a useful treatment modality. The word of cryotherapy is a general description to any therapeutic technique utilizing heat removal from the tissue by application of low temperature that could be either below or above the freezing point. The goal of application of low temperature above the freezing point in medicine is to promote vasoconstriction and decrease cellular metabolism, inflammation, pain, muscle spasm, edema and soft tissue hemorrhage. Most searches found that the temperature between 10-15°C is the optimum range for achieving this goal without causing cell damage. This temperature level can be achieved by using ice packs, cold whirlpools, controlled cold compression units and vapo-coolant sprays. It is indicated mainly in physiotherapy for musculo-skeletal trauma, pain secondary to muscle spasm and also indicated in postsurgical pain and edema.
The low temperature significantly below freezing point induces irreversible damage to the diseased or undesirable tissue. This processes is known as cryoablation and when is applied surgically, it is called cryosurgery. Cryoablation is the well-aimed and controlled destruction of diseased or undesirable tissue by application of extreme cold. It can be used in a variety of clinical applications especially in dermatology. Instrumentation and equipment used for this purposes act by several cryogens such as liquid nitrogen, nitrous oxide and carbon dioxide with a boiling point of –196°C, –89.5°C and – 78.5°C respectively, but liquid nitrogen is the most commonly used.
Cryosurgery can be used both inside the body and on the skin. In oncology, it is a highly effective treatment for a broad range of cancers including liver, prostate and breast cancer. Therapeutic applications of cryosurgery in ophthalmology include cyclocryopexy for advanced glaucoma, retinal cryoablation for retinopathy of prematurity, cryoablation of retinoblastomas, cryotherapy for malignancies of the lids and transconjunctival cryotherapy for retinal toxoplasmosis. As regarded to gynecology, the most significant indication of cryosurgery is the treatment of precancerous conditions of the cervix known as cervical intraepithelial neoplasia.
The mechanism and well-known advantages of subzero temperatures in selective freezing and destruction of the undesirable tissue, makes cryosurgery an attractive option for many dermatologic conditions. Its place in benign cutaneous lesions is well established; however, it also has great utility with malignant and premalignant lesions. Some vascular, pigmented as well as other cutaneous lesions are also amenable to freezing. The mechanism of treatment involves inducing tissue damage, vascular stasis and occlusion, as well as inflammation, to destroy unwanted tissue. After destruction of epidermal lesions, healing involves rapid re-epithelialization over a relatively cold-insensitive dermal network. Side effects of cryosurgery are common but short lived and are rarely severe. Various methods have been devised in the use of cryotherapy of lesions including; spray freeze technique, the applicator technique, the cryoprobe method and the thermo-coupler method.
Thermotherapy has long been used as an adjuvant therapy and a healing modality for treatment of several dermatologic infections that have proven sensitive to induced local use of heat or cryotherapy including; bacterial, mycobacterial, fungal, parasitic and viral infection. The rationale for the treatment of cutaneous infections with heating or freezing has been studied by many throughout the last decades, yet the exact mechanism is not entirely clear, although there is evidence that thermotherapy may involve direct toxic effects on microbes and/or up-regulation of immune response to infectious agents.
Internationally, the broadest experience with heat therapy has been in the treatment of sporotrichosis, leishmaniasis and chromomycosis. A greater elucidation of how heat therapy works in these particular infections has led to speculation regarding how heat may work in infections in general. For example, cutaneous infection with sporotrichum schenckii (causative organism of sporotrichosis) can be markedly controlled with heat above 38.5°C as this level of temperature has been showed to cause direct damage to this organism. It has also been shown that polymorphonuclear leukocyte (PMN) killing of S schenckii is also significantly enhanced at 40°C.
Similarly, early studies revealed that certain strains of leishmania, particularly leishmania tropica do not multiply at temperatures above 39°C. It was later shown that local heat therapy of cutaneous leishmaniasis leads to a systemic cytokine response similar to that induced by systemic antimonial therapy. Interferon-γ and tumor necrosis factor –α which usually increased in the inflammatory reaction and delayed hypersensitivity response associated with cutaneous leishmaniasis, were found to be decreased similarly in patients treated with either heat therapy or standard antimonial therapy. Although it is not clear if this cytokine alteration is directly caused by the therapy itself or is associated with the healing process, this alteration is further evidence that heat therapy is associated with systemic effects and immune response modification .
Lastly, it has been shown that Fonsecaea pedrosoi, the most common cause of chromomycosis, cannot sustain growth at 42.5°C. However, F pedrosoi cultures may resist death at this temperature for more than 1 month. This possible delayed resistance to direct microbe killing suggests that heat therapy works in this infection, not only via direct fungicidal destruction but also through enhanced cellular immune response .
For the majority of infections, target temperatures range from approximately 38°C to 50°C. The most basic form of heat therapy is the application of warm compresses to acute infections. A commonly used and readily available method of heating is the at-home application of electric heating pads or electric bed warmers for larger areas. There is also significant experience for benzene and disposable pocket warmers for the treatment of a variety of infectious diseases including; mycobacterial infections, sporotrichosis and chromomycosis. Water jackets and water baths have been also used in the treatment of mycobacterial infection and sporotrichosis. The less commonly used modalities include microwave and heating with ultrasound waves .
Lasers have also been used as a heating modality, particularly the CO2 laser and Nd:YAG laser. CO2 laser ablation has been used to treat condyloma acuminatum and recalcitrant verrucae with more recent experience in the treatment of leishmaniasis. There is also reported experience with Nd:YAG laser hyperthermia used in the treatment of verrucae. The development of localized current field radiofrequency has been an advance in the field of heat therapy and has been used in the treatment of acne and mycobacterial infections but more often in the treatment of leishmaniasis.
Cryotherapy for the treatment of infectious diseases has been provided with liquid nitrogen spray gun, liquid nitrogen probe, and the application of liquid nitrogen with cotton wool or cotton-tipped applicators. The application of solid CO2 (dry ice) mixtures directly to the skin for the treatment of infection have largely been abandoned by dermatologists given the risks associated with its use. Studies have also proved that cryotherapy is effective as an adjuvant therapy in the treatment of blastomycosis-like pyoderma not responding to treatment with cotrimoxazole alone