By O. Navaras. Texas Southern University.

Shoe-ftting fuoroscopy Today it is almost unbelievable that x-rays was used to fnd the right pair of shoes cheap levonorgestrel 0.18 mg. However buy levonorgestrel 0.18 mg cheap, during the period 1930 – 1950 an x-ray fuoroscope like the one shown was used order levonorgestrel 0.18 mg amex. The system consisted of a vertical wooden cabinet with an opening near the bottom into which the feet were placed. When you looked through one of the three viewing ports on the top of the cabinet (e. When you put your feet in the opening, you were standing on top of the x-ray tube. Measurements made in recent years indicate that the doses to the feet were in the range 0. Analog to digital converters and com- puters were adapted to conventional fuoroscopic image intensifer systems. Angiographic procedures for looking at the blood vessels in the brain, kidneys, arms and legs, and the blood vessels of the heart all have benefted tremendously from the adaptation of digital technology. It is reasonable to assume that all of the flm systems will be replaced by digital x-ray detectors. The digital images can be archived onto compact disks and thus save storage space. The digital images can be retrieved from an archive at any point in the future for refer- ence. On page 173 the picture of a hand is shown together with some old flm- based pictures. Let us therefore look into this technique – which played a role in the treatment of tuberculosis in the 1950s and 1960s. The technique was proposed early in the 1900s by the Italian radiologist Alessandro Vallebona. The idea is based on the simple principle of moving synchronously and in opposite directions the X-ray tube and the flm. Consequently, structures in the focal plane appear sharper, while structures in other planes appear blurred. In order to cover a Alessandro Vallebona lung about 20 x-ray pictures were required. The signals from the detectors were stored and analyzed mathematically in a computer. Scintillation detectors combined with photomultipliers or photo diodes have been used. In order to increase the sensituvity the gas detector is flled with pressurized xenon. The technique has been rapidly developed since the frst scanner presented by Hounsfeld in 1972. Both the x-ray tubes, the detector technique as well as the computer presenta- tions with flters etc. You can go to Internet and see a number of excellent pictures; for example see: http://www. These cartoons – given again below – represented a misunderstanding at that time and caused a big smile. The misunder- standing was that some people had the idea that it was possible to take x-ray pictures with refected x-rays – which means that both the x-ray tube and the flm was in the photographer’s box (like an ordinary camera). As a result of this some people feared that you could use an x-ray camera to watch people when they changed into swimming suits inside the small cabins on the beach. A London tailor company advertised therefore that they could make x-ray proof underclothing for ladies. Today with the use of Compton backscattering technique all this is a reality – and in fact in use sev- eral places for security. Today we know that it is pos- sible to use refected x-rays and see through cloths. It Scattered photon is a reaction between the x-ray photon and a free l` or loosely bound electron. With the knowledge of backscattered Compton radiation, equipment have been developed for observ- ing objects. The picture is formed by a pencil-shaped beam of x-rays that is sweeping the object. The energy used is approxi- mately 100 keV (100 – 200 kV tubes) which ensures that the Compton process is dominating. The resolution is (so far) not as good as for ordinary x-rays, but you can easily see objects with an atomic number different from that for tissue. It is possible to use the technique to see the contents of a closed container through the container walls.

The mite can be visualised using a der- transfer on clothing discount levonorgestrel 0.18 mg free shipping, shared combs buy levonorgestrel 0.18mg cheap, towels and beds may matoscope buy 0.18 mg levonorgestrel overnight delivery. Management Clinical features Patients are extremely infectious and require barrier Infestations are often asymptomatic although allergy nursing. The entire skin except the face should be treated may result in itching and lymphadenopathy. All close contacts re- louse is difficult to find but eggs (nits) may be seen along quire treatment, and clothing and bed linen should be the hair shaft. They are most common in Seborrhoeic keratoses patients who burn easily and tan poorly. There is debate Definition as to whether solar keratoses leads to squamous cell car- Seborrhoeic keratoses are a benign localised prolifera- cinoma, or whether squamous cell carcinomas arise in tion of the basal layer of the epidermis. Clinical features Lesions initially appear as a small, well-demarcated, red Incidence brown plaque that progress to become more erythema- Common; by age 40 approximately 10% of individuals tousandhyperkeratotic. Sex M = F Dermatofibromas Aetiology/pathophysiology Definition The cause of seborrhoeic keratoses is unclear, although Adermatofibroma is a cutaneous nodule containing they occur more commonly on sun-exposed skin. Sex 4F:1M Management If treatment is required, cryotherapy or currettage are Aetiology/pathophysiology usually effective. Historically dermatofibromas have been associated with trauma or insect bites, although the cause is unknown. Solar keratoses Definition Clinical features Solar keratoses or actinic keratoses are single, small scaly Lesions occur most commonly on the lower limbs. Management Age Dermatofibromas are removed only if troublesome or if Occurs in the middle-aged and elderly. Chapter 9: Skin and soft tissue lumps 405 Benign naevi Large haemangiomas can trap platelets leading to thrombocytopenia (Kasabach–Merritt syndrome). Definition r Port-wine stains are irregular reddish-purple mac- Anaevus is a hamartoma of the skin (a benign over- ules caused by permanent vascular dilatation, which growth of normal tissue). A port-wine stain in r Melanocytic naevi occurring only in the dermal– the ophthalmic division of the trigeminal nerve may epidermal junction are referred to as junctional naevi. Aetiology/pathophysiology Almost all naevi are benign, but malignant change may occur with junctional naevi at greatest risk. There is a Lipoma familial dysplastic naevus syndrome (autosomal domi- Definition nant, gene on the short arm of chromosome 1). A lipoma is a lobulated slow growing benign tumour of fatty tissue encased by a thin fibrous capsule. Clinical features All individuals have one or more benign naevi, they appear as small hyperpigmented flat or slightly raised Clinical features areas of skin. Atypical features and those suggestive Lipomastypicallypresentassoft,fluctuantmassseparate of malignancy are described later in section Malignant from the overlying skin. If there is any diagnostic uncertainty an elliptical excision biopsy Management and histopathological evaluation should be performed. Haemangiomas Epidermoid cysts Definition Definition Ahaemangioma is an arteriovenous malformation or An epidermoid cyst is an epithelium-lined cavity within proliferation of abnormal blood vessels. Theyusuallydevelopinthefirstfewweeksoflife, and are thought to arise from the blockage of a hair grow toamaximuminthefirstyearandthengradually follicle. Clinical features r Cavernous haemangioma are larger and deeper vas- Patients present with a lump in the skin, so the skin can- cular lesions, which may be covered by normal skin. A characteristic surface punctum 406 Chapter 9: Dermatology and soft tissues is often visible. If there is a superimposed infection the Aetiology lump may become red, hot and tender. It is thought that there is herniation of synovial tissue from a joint capsule or tendon sheath. Management r Uninfected cysts are excised under local anaesthesia, if required using an elliptical incision. Excision Aganglion may present as a swelling or pain commonly is performed if still necessary once the infection has around the wrist or the dorsum of the hand. Aspiration and Definition injection of a crystalline steroid may be useful, and in- Acyst arising from deep implanted epidermal cells. Aetiology/pathophysiology Dermoid cysts arise from epidermal cells, which have been implanted into the dermis either during embry- Skin tumours onic development or following trauma. They are lined with squamous epithelium and contain sebum, cells and occasionally hair. The surrounding skin Sex and subcutaneous tissue may be erythematous and M > F swollen. Geography Management Most common in Caucasians, and uncommon in dark- Dermoid cysts are surgically removed. Aetiology Basal cell carcinomas are predisposed to by light and ionising radiation. Sun exposure is the most important Ganglion aetiological factor particularly in individuals with fair Definition skin, pale eyes and red hair. Childhood sun exposure Abenign cystic swelling occurring over a joint or tendon appears to be important, especially if there is repeated sheath.

A variety of tick control programmes may be integrated into livestock management: Chemical control purchase 0.18mg levonorgestrel with mastercard. Acaricides are most effectively applied through total immersion of livestock in a dip-vat cheap levonorgestrel 0.18 mg without prescription. They may also be applied as sprays cheap levonorgestrel 0.18mg, dusts, pour-ons, spot-ons and more recently via slow release technologies such as impregnated ear tags, or systemically from implants or boluses. Treatment may vary from every three days (as followed in east Africa for the protection of cattle against East Coast fever transmission by Rhipicephalus appendiculatus) to every six months (for the control of Rhipicephalus (formerly Boophilus) microplus tick populations). Organochlorines, organophosphates, carbamates, amidines, avermectins and pyrethroids have been used for tick control. The development of acaricide resistance in ticks has necessitated the development of new compounds, such as phenylpyrazoles. Acaricide usage is not considered sustainable as they are expensive, can cause environmental damage, may leave potentially harmful residues in meat and milk and ticks can develop resistance over time. This permits the re-infection of immune livestock, boosting immunity and leading to endemic stability. Tick-resistant cattle and their cross breeds may be exploited as a method to control the parasitic stages of ticks. Although these breeds continue to support tick populations, they are not conducive to large tick infestations. The use of Zebu cattle has been successful in Australia and the introduction of tick-resistant cattle is becoming an increasingly important method of tick control in the Americas and Africa. Pasture rotation or pasture spelling can be used as a method to control one- host tick species (such as Rhipicephalus microplus, an economically important parasite of livestock that spreads the pathogens responsible for babesiosis). Larval ticks are starved due to the absence of their host, so the duration of pasture spelling is determined by the lifespan of the free-living larvae. This method has minimal application to soft ticks (nymphs can survive for long periods without food) and multi-host tick species. Notable vaccination programmes include the development of an East Coast fever vaccine in Kenya and the implementation of a vaccine for tick fever in Australia. Furthermore, live attenuated vaccines have been used to control tropical theileriosis (caused by Theileria annulata) and heartwater (caused by Ehrlichia, formerly Cowdria ruminantium). In all tick-borne disease-free areas or countries, it is recommended that livestock are inspected for ticks before allowing entry. Area quarantine, on areas with large infestations, ensures all livestock are inspected for ticks and given precautionary treatment before leaving. Premises quarantines act to prevent the spread of infested livestock from individual pastures, farms or ranches with suitable physical barriers. Manual tick removal may also provide an effective control method for small numbers of animals. Wildlife Control of wildlife populations may be difficult, but the interaction of livestock and wildlife should be prevented where possible. Avoid and repel ticks: Walk in the centre of trails to avoid contact with overgrown vegetation. Companion animals should be routinely checked for ticks; cats and dogs can be treated with commercially available acaricide dusts or washes. Control of vectors: tick control Educational talks and informative material (such as brochures and pamphlets) can also help reduce the likelihood of tick bites and zoonotic disease transmission, especially for high-risk employees such as reserve wardens. Signage, warning people they are entering tick-infested areas, may also help reduce the incidence of tick bites. Livestock may also suffer direct impacts from feeding ticks: Tick paralysis and toxicosis. Some are external parasites (ectoparasites); some attach themselves to internal organs (endoparasites); others are semi-external, attaching themselves to the lining of the mouth, to the gills or to the cloaca. Some species are zoonotic, causing lung, liver and intestinal fluke diseases in humans, and trematodes have been reported to affect the health of more than 40 million people throughout the world. The trematodiasis group are considered as some of the most medically important parasitic zoonoses where a large number of fish species, both marine and freshwater, are potential sources of infection. Some trematodes are potentially pathogenic and the main pathway for human infection is through consumption of raw or inadequately cooked fish. Causal agent Clonorchiasis is caused by Clonorchis sinensis (Chinese liver fluke); opisthorchiasis is caused by two species: Opisthorchis viverrini (Southeast Asian liver fluke) and O. Intestinal trematodiases are caused by intestinal trematode parasites belonging to the families Heterophyidiae and Echinostomatidae and several genera such as Metagonimus, Heterophyes and Haplorchis. Schistosome species that cause bloodfluke infections are mainly restricted to the tropical and subtropical areas and belong to the genera Schistosoma and Orientobilharzia. These include both zoonotic and non-zoonotic species and typically occur in cattle, buffaloes, goats and pigs. A large number of gastro-intestinal trematode species (paramphistomes) have been described. They can infect all ruminants but young calves and lambs are the most susceptible.