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The vessels from this group empty into the thoracic duct or tracheobronchial nodes (Figure 11-2) purchase 500 mg zithromax free shipping. The lungs have superficial and deep lymphatic plexuses that drain into the bron- chopulmonary (hilar) lymph node order zithromax online now. The deep plexuses buy cheapest zithromax and zithromax, however discount zithromax american express, first drain through pulmonary nodes along the bronchi within the lung, from which the lymph passes to the bronchopulmonary nodes. Lymph then drains to inferior and superior tracheo- bronchial nodes (below and above the tracheal bifurcation) and tracheal nodes located along the sides of the trachea. The bronchopulmonary lymph node group is located at the hilum of each lung, and it receives lymph from the superficial and deep lymphatic plexuses. The anterior mediastinum lies immediately posterior to the sternum and contains the thymus in children. Tissue analysis by the pathologist under the microscope reveals intraductal carcinoma. The patient is advised by the surgeon to have surgery to remove the primary breast mass in addition to some lymph nodes. Levels 1, 2, and 3 are lateral to, deep to, and medial to the pectoralis minor, respectively. Pathological examination revealed intraductal carcinoma in the core needle biopsy. Risk factors include the patient’s age, and intraductal carcinoma is the most common histological type. The most common treatment plan would be a breast-conserving procedure such as a lumpectomy (excis- ing the malignant mass with some margins) and axillary lymph node dissection. The presence or absence of malignant cells in the axillary lymph nodes is the single most important prognostic factor for survival. Options for nodal staging include level 1 and 2 axillary node dissection versus sentinel node biopsy. The sentinel node(s) represents the node(s) to which primary lymph drainage occurs from a tumor or ana- tomical site. It is identified by injection of radiotracers and a blue dye at the primary tumor site. Biopsy of the sentinel node(s) results in a smaller incision and decreased trauma to the axilla. However, if the sentinel node(s) is positive for metastatic disease, a complete level 1 and 2 axillary dissection should be performed. Other physical signs of breast cancer, which this patient did not have, include skin dimpling or retraction, which is formed by the underlying cancer adherent to the fibrous septa of the breast, and the thickened red appearance of peau d’orange, which is caused by the malignant cells proliferating within the lymphatics underlying the skin. A red, warm breast in a non-breast-feeding woman can also represent inflam- matory breast cancer due to malignancy within the lymphatic channels of the skin. Be able to describe the anatomy of the adult female breast, including the blood and nerve supplies. Be able to list the primary path for lymphatic drainage of the breast and the several subgroups of axillary nodes. The long thoracic Pectoralis major muscle Fat Ligaments of Cooper Mammary lobules (glands) Lactiferous ducts Lactiferous sinuses figure 12-1. Each breast is centered by the elevated nipple, which contains the open- ings of the lactiferous ducts and is composed of circular smooth muscle. Surround- ing the nipple is pigmented skin or the areola, which contains the opening of the lubricating sebaceous glands. The radially arranged mammary gland tissue forms 15 to 20 lobes, each drained by a lactiferous duct that has a dilatation called the lactiferous sinus just before its opening onto the nipple. The lobes are irregularly separated by incomplete dense connective tissue septae that attach to the dermis of the overlying skin. These septae, called the suspensory ligaments (of cooper), are especially well developed in the superior half of the breast. A loose connective tissue layer, the retromammary space, separates the breast components and the pectoral fascia, allowing for some movement. The breast overlies the pectoralis major and the anterior portion of the serratus anterior muscles. A portion of breast tissue typi- cally extends into the axilla as the axillary tail (of Spence). The breast is supplied by branches of the internal thoracic, lateral thoracic, and anterior and posterior intercostal arteries. The breast is innervated by anterior and lateral cutaneous branches of intercostal nerves. The majority of lymph drained from the breast (usually quantified at 75 percent) drains to the axillary lymph nodes. The axillary node group is often described as a pyramid, like the axilla, and is typically subdivided into five subgroups: pectoral (anterior), lat- eral (humeral), posterior (subscapular), central (medial), and apical. Lymph from the axillary nodes typically drains into the inferior deep cervical lymph nodes. However, lymph from the axillary node group may drain into other nodes such as the interpectoral and deltopectoral nodes (Figure 12-2). This is especially true in instances of metastasis because “normal” paths become blocked by the malignancy and alternate routes must be established. The pectoral, humeral, and subscapular nodes are level 1 nodes, whereas the central and apical nodes are level 2 and 3 nodes, respectively. The medial quadrants of the breast will have lymph drain into the parasternal lymph nodes along the internal thoracic vessels. In addition to the breast tis- sue on the chest, what other region is critical to complete the palpation of mammary tissue? She com- plains of breast engorgement and swelling in regions at about the level of the umbilicus and at the lateral abdomen. The “milk line” extends from the axilla to the groin area, and accessory mammary tissue may be present anywhere along this line. The patient likely has an injury to the left long thoracic nerve, and the deficits resulting from weakness to the left serratus anterior muscle. Injury to the long thoracic nerve leads to inability to abduct the arm past 90 degrees, and also the appearance of a “winged scapula. A sentinel node biopsy is a less extensive surgery and not as likely to injure this nerve. Her history is unremarkable except for a vague history of fever and joint pain as a child in Mexico. She notes some recent fatigue and difficulty sleeping that she attributes to job-related stress. On examination, her heart rate is 120 beats/min, and the rhythm has no discernible pattern (is irregularly irregular). Auscultation of the heart indicates a systolic murmur (during left ventricular ejection of blood) that is harsh in character. In this patient, the history of childhood fever and joint pain likely is the result of strepto- coccally caused rheumatic fever. If untreated, the microorganism can cause inflam- mation of the mitral valve, leading to mitral stenosis. After 3-5 years, the mitral stenosis is likely to worsen, leading to atrial enlargement, fibrillation, and pulmo- nary edema with intolerance to physical exertion. An ultimate goal will be conversion of her cardiac contractions to a normal sinus rhythm. Anti- coagulation is often warranted in the face of long-term atrial fibrillation because of the likelihood of intracardiac thrombus and the possibility of emboli after conver- sion to sinus rhythm, called the “atrial stunning” effect. Be able to describe the type of tissue that makes up the cardiac conduction system 2. Be able to describe the nature of sinus rhythm and the influence of the divisions of the autonomic nervous system on this rhythm 4. It initiates and rapidly conducts cardiac impulses throughout the heart to produce cardiac muscle contraction.

In contrast buy zithromax canada, strains of Streptococcus pneumoniae are resistant to multiple antibiotics order zithromax 100 mg amex, including erythromycin and trimethoprim/sulfamethoxazole buy zithromax 100 mg line, as well as amoxicillin and other beta-lactam antibiotics discount generic zithromax uk. The clavulanate (clavulanic acid) in the combination inhibits beta-lactamase and thereby increases activity against resistant H. Because the clavulanate in the combination can cause diarrhea, the dosage of clavulanate should be low. It is important to be aware that the ratio of amoxicillin to clavulanate is not constant. For example, Augmentin (amoxicillin with clavulanate) is available as tablets containing 250 mg amoxicillin with 125 mg clavulanate and as tablets containing 500 mg amoxicillin with 125 mg clavulanate. If two tablets containing 250 mg amoxicillin are administered to give a patient a 500-mg dose of the amoxicillin component, the excess of clavulanate can result in worsening diarrhea. Two additional measures are prevention and treatment of influenza and vaccination against pneumococcal infection. Two methods are available: (1) vaccination against influenza and (2) treatment of active influenza infection. Four management strategies are available: (1) short-term antibacterial therapy, (2) prophylactic antibacterial therapy, (3) prevention and treatment of influenza, and (4) placement of a tympanostomy tube. Short-Term Antibacterial Therapy There is disagreement among experts regarding antibacterial therapy. Some authorities recommend antibiotics for each recurrent episode, regardless of presentation. Prophylactic Antibacterial Therapy Antibacterial prophylaxis is not generally recommended. An analysis of several studies indicates that, for each year of prophylaxis (with trimethoprim/sulfamethoxazole, or amoxicillin), only 1. This small benefit is largely outweighed by the risk for promoting antibiotic resistance. If prophylaxis is elected, it should be conducted only during the upper respiratory infection season. The preferred drug for prophylaxis is amoxicillin because, compared with sulfonamides, amoxicillin is more active against multidrug-resistant strains of S. Tympanostomy Tubes A tympanostomy tube permits drainage and aeration of the middle ear. Complications of the procedure include obstruction of the tube, secondary infection with otorrhea, and premature tube extrusion. The condition is characterized by fluid in the middle ear but without evidence of local or systemic illness. First, topical agents achieve very high local concentrations (often 100–1000 times the concentration achieved with systemic drugs), antibacterial effects are superior, disease persistence is lower, and recurrence is less likely. Exceptions are made for patients with diabetes, immune deficiencies, or those who would have difficulty with proper administration of topical drugs. A solution of alcohol plus acetic acid offers the additional benefit of promoting tissue drying. If the infection is more extensive or cannot be cleared with acetic acid and alcohol, a topical antibiotic should be employed. In the past, a three-drug combination—hydrocortisone, neomycin, and polymyxin B—was considered standard therapy. The hydrocortisone reduces inflammation and edema; neomycin and polymyxin kill bacterial pathogens. Unfortunately, although this combination is effective and inexpensive, it has drawbacks. Specifically, the neomycin component is ototoxic and causes local swelling and erythema in about 15% of patients. Unlike many otic preparations, quinolones and quinolone/glucocorticoid combinations are safe for patients who have perforated tympanic membranes. The glucocorticoid has the added benefit of decreasing pain by reducing swelling caused by inflammation. Principal drawbacks of these preparations are expense and the potential to promote resistance to quinolone antibiotics. Applying ear drops correctly can improve outcomes and reduce drug-related discomfort. Instillation of cold solutions can cause dizziness; therefore, ear drops should be warmed before administration. The wick should be replaced at least every 48 hours to allow cleaning and to determine whether further wicking is still needed. For adults, ciprofloxacin [Cipro] is a good choice; however, because oral quinolones can cause tendon rupture in younger patients, it should not be given to patients younger than 18 years. Spread of infection to the skull base can affect cranial nerves, and spread to the dura mater can cause meningitis and possibly lateral sinus thrombosis. The two most common pathogens are Aspergillus, which causes 80% to 90% of otomycoses, and Candida. As a rule, otomycosis can be managed with thorough cleansing and application of acidifying drops (e. If these measures are inadequate, the patient can apply a solution that contains an antifungal drug (e. Complications include development of language problems secondary to hearing deficits and development of drug-resistant bacteria (primarily as a result of not taking medication as directed or stopping them prematurely). Identifying High-Risk Patients • Assess for penicillin allergy before prescribing amoxicillin or amoxicillin/clavulanate. For patients who have experienced a mild reaction to penicillins, guidelines recommend a cephalosporin such as cefdinir, cefuroxime, or cefpodoxime. For a severe reaction such as anaphylaxis, azithromycin or clarithromycin is recommended. Instead, prescribe a quinolone or quinolone/glucocorticoid combination because these are safe for patients who have perforated tympanic membranes. Before leaving the clinic, they should be instructed to return if they do not have improvement or if their condition worsens. For this reason, tympanometry and pneumatic otoscopy will not reflect a normal response to pressure changes for several weeks or even months. Many of these protocols allow for the replacement of electrolytes by the registered nurse. Three groups of agents are considered for replacement: (1) drugs used to correct disorders of fluid volume and osmolality, (2) drugs used to correct disturbances of hydrogen ion concentration (acid-base status), and (3) drugs used to correct electrolyte imbalances. Disorders of Fluid Volume and Osmolality Good health requires that both the volume and osmolality of extracellular and intracellular fluids remain within a normal range. If a substantial alteration in either the volume or osmolality of these fluids develops, significant harm can result. Maintenance of fluid volume and osmolality is primarily the job of the kidneys, and, even under adverse conditions, renal mechanisms usually succeed in keeping the volume and composition of body fluids within acceptable limits. However, circumstances can arise in which the regulatory capacity of the kidneys is exceeded. Abnormal states of hydration can be divided into two major categories: volume contraction and volume expansion. Volume contraction is defined as a decrease in total body water; conversely, volume expansion is defined as an increase in total body water. States of volume contraction and volume expansion have three subclassifications based on alterations in extracellular osmolality. For volume contraction, the subcategories are isotonic contraction, hypertonic contraction, and hypotonic contraction. In the clinical setting, changes in osmolality are described in terms of the sodium content of plasma. Sodium is used as the reference for classification because this ion is the principal extracellular solute. In most cases, the total osmolality of plasma is about 2 times the osmolality of sodium. Volume Contraction Isotonic Contraction Definition and Causes Isotonic contraction is defined as volume contraction in which sodium and water are lost in isotonic proportions. Hence, although there is a decrease in the total volume of extracellular fluid, there is no change in osmolality. Causes of isotonic contraction include vomiting, diarrhea, kidney disease, and misuse of diuretics. Hypertonic Contraction Definition and Causes Hypertonic contraction is defined as volume contraction in which loss of water exceeds loss of sodium.

At low therapeutic concentrations generic zithromax 250mg visa, the drug produces spastic paralysis discount zithromax 500 mg visa, causing detachment of worms from body tissues order zithromax 250 mg. At high therapeutic concentrations cheap zithromax 500mg overnight delivery, praziquantel disrupts the integument of the worms, rendering the parasites vulnerable to lethal attack by host defenses. The drug undergoes extensive hepatic metabolism, followed by excretion in the urine. Drowsiness may occur, and hence patients should avoid driving and other hazardous activities. Diethylcarbamazine Target Organisms Diethylcarbamazine [Hetrazan] is the drug of choice for filarial infestations. First, it reduces muscular activity, causing parasites to be dislodged from their site of attachment. Second, by altering the surface properties of the parasites, it renders the organisms more vulnerable to attack by host defenses. Pharmacokinetics Diethylcarbamazine is readily absorbed and undergoes rapid and extensive metabolism. Adverse Effects Adverse effects caused directly by diethylcarbamazine are minor (headache, weakness, dizziness, nausea, vomiting). Indirect effects, occurring secondary to death of the parasites, can be more serious. These include rashes, intense itching, encephalitis, fever, tachycardia, lymphadenitis, leukocytosis, and proteinuria. Fortunately, these reactions are transient, lasting just a few days—and can be minimized by pretreatment with glucocorticoids. Ivermectin Target Organisms Ivermectin [Stromectol] is active against many nematodes. Currently, the drug has two approved indications: onchocerciasis (a major cause of blindness worldwide) and intestinal strongyloidiasis. Ivermectin can also be used to kill mites and lice, although these parasites are not approved targets. In addition to its use in humans, ivermectin is used widely in veterinary medicine. Mechanism of Action Ivermectin disrupts nerve traffic and muscle function in target parasites. By opening chloride channels on the cell surface, which allows chloride ions to rush into nerve and muscle cells. The resultant hyperpolarization of these cells causes paralysis followed by death. Host cells are not affected because ivermectin is selective for chloride channels in parasites. Pharmacokinetics Ivermectin is administered orally and achieves peak plasma levels in 4 hours. Adverse Effect: Mazotti Reaction The Mazotti reaction occurs in patients treated for onchocerciasis. Principal symptoms are pruritus, rash, fever, lymph node tenderness, and bone and joint pain. The apparent cause is an allergic and inflammatory response to the death of microfilariae. Although the nonspecialist provider does not typically have an active role in deciding how to treat cancer, as part of the interdisciplinary team caring for the patient, it remains essential to provide preventive care and to promote optimal well-being for those patients who receive treatment. Hence it is important to have a basic understanding of cancer, drugs used to treat cancer, and the effects that anticancer drugs have on patients. In the discussion that follows, we consider properties shared by neoplastic cells as a group. However, although the discussion addresses cancers in general, be aware that the term cancer refers to a large group of disorders and not to a single disease: there are more than 100 different types of cancer, most of which have multiple subtypes. These various forms of cancer differ in clinical presentation, aggressiveness, drug sensitivity, and prognosis. Because of this diversity, treatment is individualized, based on the specific biology of the cells involved. Characteristics of Neoplastic Cells Persistent Proliferation Unlike normal cells, whose proliferation is carefully controlled, cancer cells undergo unrestrained growth and division. This capacity for persistent proliferation is the most distinguishing property of malignant cells. In the absence of intervention, cancerous tissues will continue to grow until they cause death. It was once believed that cancer cells divided more rapidly than normal cells and that this excessive rate of division was responsible for the abnormal growth patterns of cancerous tissues. The correct explanation for the relentless growth of tumors is that malignant cells are unresponsive to the feedback mechanisms that regulate cellular proliferation in healthy tissue. As a result, cancer cells are able to continue multiplying under conditions that would suppress further growth and division of normal cells. In other words, instead of dividing more rapidly, they divide more frequently than normal cells. Invasive Growth In the absence of malignancy, the various types of cells that compose a tissue remain segregated from one another; cells of one type do not invade territory that belongs to cells of a different type. In contrast, malignant cells are free of the constraints that inhibit invasive growth. As a result, cells of a solid tumor can penetrate adjacent tissues, thereby allowing the cancer to spread. Formation of Metastases Metastases are secondary tumors that appear at sites distant from the primary tumor. Metastases result from the unique ability of malignant cells to break away from their site of origin, migrate to other parts of the body (through the lymphatic and circulatory systems), and then reimplant to form a new tumor. Immortality Unlike normal cells, which are programmed to differentiate and eventually die, cancer cells can undergo endless divisions. The underlying cause for this difference is telomerase, an enzyme that is active in most cancers, and expressed only rarely in normal cells. As normal cells divide and differentiate, their telomeres become progressively shorter. When telomeres have lost a critical portion of their length, the cell is unable to keep on dividing. In cancer cells, telomerase continually adds back lost pieces of the telomere, and thereby preserves or extends telomere length. Specifically, malignant transformation results from a combination of activating oncogenes (cancer-causing genes) and inactivating tumor suppressor genes (genes that prevent replication of cells that have become cancerous). These genetic alterations are caused by chemical carcinogens, viruses, and radiation (x- rays, ultraviolet light, radioisotopes). Malignant transformation occurs in three major stages, called initiation, promotion, and progression. This accumulated genetic damage leads to dysregulation of cell division and protection against cell death. It is important to appreciate that the changes in cellular function caused by malignant transformation are primarily quantitative rather than qualitative. That is, malignant transformation simply results in the overexpression or underexpression of the same gene products made by normal cells. As a result, cancer cells employ the same metabolic machinery as normal cells, use the same signaling pathways as normal cells, and express the same surface antigens as normal cells. Nonetheless, even though these changes in cellular function are only quantitative, they are still sufficient to allow unrestrained growth and avoidance of cell death. Epidemiology The American Cancer Society estimated that 589,430 Americans died from cancer in the year 2015. Cancer is a leading cause of death among all age groups, including children aged 1 to 18 years, in whom it is the leading nonaccidental cause of death. Among men, the most common cancers are prostate, lung, and colorectal cancer (Table 82. Cancers with a high cure rate include Hodgkin disease, testicular cancer, and acute lymphocytic leukemia. For many patients whose cancer is not yet curable, chemotherapy can still be of value, offering realistic hopes of palliation and prolonged life.