Rebecca M. T. Law, BS Pharm, PharmD

Susceptible individuals span a broad immunologic spectrum hypertension differential diagnosis buy genuine enalapril, from anergy to hyperergy and may develop symptomatic infection hypertension updates 2014 buy generic enalapril from india. At one end of the spectrum heart attack 22 purchase enalapril online now, anergic patients have little or no resistance and develop lepromatous leprosy heart attack effects quality enalapril 5 mg, whereas hyperergic patients with high resistance contract tuberculoid leprosy arteria 3d castle pack 2 order enalapril with mastercard. In these patients, although macrophages phagocytose the organisms, they cannot kill them. The bacilli replicate, fill the cells and spread first to other macrophages and then throughout the body via the lymphatics and bloodstream. Progressive small bowel involvement produces malabsorption and diarrhea, often with abdominal pain. Of these, most are "opportunists"-that is, they only infect people with impaired immune mechanisms. They vary from 2 to 100 m and are eukaryotes meaning that they possess nuclear membranes and cytoplasmic organelles, such as mitochondria and endoplasmic reticulum. Tuberculoid leprosy is characterized by a single lesion or very few lesions of the skin, usually on the face, extremities or trunk. Microscopically, lesions show well-formed, circumscribed, dermal, noncaseating granulomas with epithelioid macrophages, Langhans giant cells and lymphocytes. Skin lesions form well-demarcated, hypopigmented or erythematous, dry, hairless patches, with raised outer edges that are characterized by decreased sensation. Lepromatous leprosy exhibits multiple, tumor-like lesions of the skin, eyes, testes, nerves, lymph nodes and spleen. Foamy macrophages contain numerous organisms, which appear as aggregates of acid-fast material, called "globi. Involvement of the upper airways leads to chronic nasal discharge and voice change. In persons with intact cell-mediated immunity, infection is rapidly contained without producing symptoms. If the process is not checked by the host immune system or antibiotic therapy, the infected alveoli eventually fill with Multidrug therapy using a combination of rifampicin, dapsone and other agents is critical, as monodrug therapy always results in the development of resistance. There is diffuse involvement, including a leonine face, loss of eyebrows and eyelashes and nodular distortions, especially on the face, ears, forearms and hands-the exposed (cool) parts of the body. A characteristic "clear zone" of uninvolved dermis separates the epidermis from tumor-like accumulations of macrophages, each containing numerous lepra bacilli (Mycobacterium leprae). Skin from the raised "infiltrated" margin of the plaque contains discrete granulomas that extend to the basal layer of the epidermis (without a clear zone). A silver stain shows crescent-shaped organisms, which are collapsed and degenerated. Microscopically, the alveoli contain a frothy eosinophilic material, composed of alveolar macrophages and cysts and trophozoites of P. The progressive filling of alveoli prevents adequate gas exchange, and the patient slowly suffocates. Therapy is with trimethoprim-sulfamethoxazole, pentamidine, atovaquone or several other regimens. Many Candida species are endogenous human flora, well adapted to life on or in the human body. Chronically warm and moist areas, such as between fingers and toes, between skin folds and under diapers, are prone to superficial candidal disease. Although the forms of candidiasis vary in clinical severity, most are localized superficial diseases, limited to a particular mucocutaneous site, such as oral infections (thrush), esophagitis, vulvovaginitis and others. Superficial infections may be linked to eradication of resident bacterial fauna (such as by antibiotic use) because such fauna are important in host defense against candida. Candidal infections of deep tissues, with concomitant sepsis and dissemination, occur only in immunologically compromised persons and are often fatal. There are three types of pulmonary aspergillosis: (1) allergic bronchopulmonary aspergillosis, (2) colonization of a pre-existing pulmonary cavity (aspergilloma or fungus ball) and (3) invasive aspergillosis. In tissues, Aspergillus show septate hyphae, 2 to 7 m in diameter, branching progressively at acute angles. Bronchi and bronchioles show infiltrates of lymphocytes, plasma cells and variable numbers of eosinophils. Inhaled spores germinate in the warm humid atmosphere provided by these hollows and fill them with masses of noninvasive hyphae. Inhaled spores germinate to produce hyphae, which invade through bronchi into the lung parenchyma, from where the fungi spread widely. Microscopically, Aspergillus hyphae are arranged radially around blood vessels and extend through their walls. Acute aspergillosis may also start in a nasal sinus and spread to the face, orbit and brain. The main reservoir for the fungus is pigeon droppings and, when inhaled, the organisms reach the terminal bronchioles. Cryptococcus almost exclusively affects persons with impaired cell-mediated immunity. The same section stained with mucicarmine illustrates the capsule of the organism. B and exposure is common, the infection is rare in the absence of predisposing illness. By contrast, in a patient with defective cellmediated immunity, the cryptococci survive, reproduce locally and then disseminate. In meningoencephalitis, the entire brain is swollen and soft and the leptomeninges are thickened and gelatinous from infiltration by the thickly encapsulated organisms. Inflammatory responses are variable and often minimal, with large numbers of cryptococci infiltrating tissue. It is characterized by necrotizing granulomas in the lung, mediastinal and hilar lymph nodes, spleen and liver. Disseminated histoplasmosis develops in persons who fail to mount an effective immune response to H. Most infections are asymptomatic, but with extensive disease, patients present with fever, headache and cough. Although disseminated disease may persist for years, profound immunodeficiency is accompanied by rapid progress of the disease, with high fever, cough, pancytopenia and changes in mental status. Coccidioides immitis is a dimorphic fungus that grows as a mold in the soil, where it forms spores. Most are mild and asymptomatic and are limited to the lungs and regional lymph nodes. The disease is usually self-limited but may lead to a systemic granulomatous disease. Although most cases of histoplasmosis are asymptomatic, progressive disseminated infections occur in persons with impaired cell-mediated immunity. The organism is endemic along the Ohio and Mississippi river valleys of the central and eastern United States and also occurs in other areas of the Americas. A section of liver from a patient with disseminated histoplasmosis reveals Kupffer cells containing numerous yeasts of H. B common in the San Joaquin Valley of California, where it is called valley fever. Epidemics have been associated with sandstorms and earthquakes, which produce airborne spores. Subsequent cell-mediated immune responses kill or contain the fungi-a process followed by healing of the granuloma. The course of coccidioidomycosis depends on the size of the infecting dose and the immune status of the host. Extensive pulmonary involvement and fulminant disease may occur in persons from a nonendemic region exposed to large numbers of organisms. Disseminated coccidioidomycosis occurs in immunocompromised persons either from a primary infection or reactivation of old disease. Disseminated disease may involve almost any body site and may manifest as a single extrathoracic site or as widespread disease, including lesions of the skin, bones, meninges, liver, spleen and genitourinary tract. Pregnant women are also unusually predisposed to spread of the disease if they develop primary infection during the latter half of pregnancy. Even with prolonged amphotericin B therapy, the prognosis is poor in acute disseminated coccidioidomycosis, although the response rate can be quite good with some of the newer azole antifungal agents. The causative organism, Blastomyces dermatitidis, is a dimorphic fungus that grows as a mold in warm moist soil, rich in decaying vegetable matter. Disturbance of the soil, either by construction or by leisure activities such as hunting or camping, leads to the formation of aerosols containing fungal spores. The host responds to the proliferating organisms with a mixed suppurative and granulomatous inflammatory response, producing a focal bronchopneumonia. A photomicrograph of the lung from a patient with acute coccidioidal pneumonia shows an acute inflammatory infiltrate surrounding spherules and endospores of Coccidioides immitis. The parasites infect and destroy human erythrocytes, producing chills, fever, anemia and splenomegaly. Although malaria has been eradicated in developed countries, more than 1,500 cases of malaria are detected yearly in the United States, almost all imported by returning travelers or immigrants. The rupture of infected erythrocytes releases pyrogens and causes the recurrent paroxysms of chills and high fever characteristic of malaria. Paroxysms recur for weeks, eventually subsiding as an immunologic response is mounted. Each paroxysm reflects another round of the rupture of infected erythrocytes and release of daughter organisms. Anemia results both from loss of circulating infected erythrocytes and sequestration of cells by fixed mononuclear phagocytes in the enlarging spleen. Liver, spleen and lymph nodes are darkened by macrophages filled with hemosiderin and malarial pigment, the end product of parasitic digestion of hemoglobin. With hematoxylin and eosin stains, the yeast are rings with thick, sharply defined cell walls. Organisms persist until the onset of specific hypersensitivity and cell-mediated immunity, when activated neutrophils and macrophages kill them. Pulmonary disease is usually self-limited and resolves by scarring, but some patients develop progressive miliary lesions or cavities. Symptomatic acute infection presents as a flu-like illness, with fever, arthralgias and myalgias. There are about 40 species of dermatophytes in three genera: Trichophyton, Microsporum and Epidermophyton. Dermatophyte infections are minor illnesses but are among the most common skin diseases for which persons seek medical help. The disease is usually acquired by direct contact with persons who have infected hairs or skin scales. They spread centrifugally from the initial site, producing round, expanding lesions with sharp margins. The appearance once suggested that a worm was responsible for the disease, hence the names ringworm and tinea (from the Latin tinea, "worm"). Infections produce thickening of the squamous epithelium, with increased numbers of keratinized cells. Some, such as Entamoeba histolytica, are extracellular parasites capable of digesting and invading human tissues. Others, such as plasmodia, are obligate intracellular parasites that replicate in, and kill, human cells. Still others, such as trypanosomes, damage human tissue largely by eliciting inflammatory and immunologic responses. The organism alters flow characteristics and adhesive properties of infected erythrocytes, which adhere to the endothelial cells of small blood vessels. Obstruction of small blood vessels frequently produces severe tissue ischemia of the brain, kidneys and lungs, which is probably the most important factor in the virulence of P. The brains of persons who die of cerebral malaria show congestion and thrombosis of small blood vessels in the white matter, which are rimmed with edema and hemorrhage ("ring hemorrhages"). Obstruction of renal blood flow produces acute renal failure, whereas intravascular hemolysis leads to hemoglobinuric nephrosis (blackwater fever). In the lung, damage to alveolar capillaries produces pulmonary edema and acute alveolar damage. Ischemic brain injury causes symptoms ranging from somnolence, hallucinations and behavioral changes to seizures and coma. An Anopheles mosquito bites an infected person, taking blood that contains microgametocytes and macrogametocytes (sexual forms). In the mosquito, sexual multiplication (sporogony) produces infective sporozoites in the salivary glands. Some sporozoites leave the blood and enter the hepatocytes, where they multiply asexually (exoerythrocytic schizogony) and form thousands of uninucleated merozoites. Schizonts divide to form more merozoites, which are released on the rupture of erythrocytes and re-enter other erythrocytes to begin a new cycle. After several cycles, subpopulations of merozoites develop into microgametocytes and macrogametocytes, which are taken up by another mosquito to complete the cycle. Ruptured erythrocytes release hemoglobin, erythrocyte debris and malarial pigment. The final host is the cat, which becomes infected by ingesting cysts of the organism from an infected mouse, bird, human or other intermediate host. The organism multiplies within the intestinal epithelial cells of the cat and is shed in the feces. Infected persons suffer few clinical effects, the most frequent of which is lymphadenopathy, sometimes accompanied by fever, sore throat, hepatosplenomegaly and circulating atypical lymphocytes. The histology of affected lymph nodes is distinctive, with numerous epithelioid macrophages surrounding and encroaching on reactive germinal centers. If an infected person loses cell-mediated immunity, the organism can emerge from its encysted form and reestablish a destructive infection. Toxoplasma encephalitis in immunocompromised patients is fatal if not treated with effective antiprotozoal agents.

Although this lesion is conventionally termed an aneurysm arrhythmia untreated enalapril 10 mg, it is actually a form of hematoma blood pressure chart by time of day enalapril 5 mg order with amex. Dissecting aneurysms most often affect the ascending aorta and major branches of the aorta prehypertension exercise order 5 mg enalapril with mastercard. Thoracic dissections may involve the ascending aorta alone (type A) or the distal aorta sparing the ascending aorta (type B) blood pressure 6030 generic enalapril 10 mg visa. Their frequency has been estimated to be as high as 1 out of 400 autopsies blood pressure medication uk enalapril 10 mg cheap, with men affected three rysms is usually weakening of the aortic media. The changes were originally described as cystic medial necrosis (of Erdheim) because focal loss of elastic and muscle fibers in the media creates "cystic" spaces filled with a metachromatic myxoid material. Aging also results in mild degenerative changes in the aorta, characterized by focal elastin loss and medial fibrosis. Thoracic aorta with metal clamps revealing the dissection and hematoma in the wall with old blood clot. The thoracic aorta has been opened longitudinally and reveals clotted blood dissecting the media of the vessel. A section of the aortic wall stained with aldehyde fuchsin shows pools of metachromatic material characteristic of the degenerative process known as cystic medial necrosis. Mycotic aneurysms may also occur adjacent to a focus of tuberculosis or a bacterial abscess. It is widely held that spontaneous laceration of the intima allows blood from the lumen to enter and dissect the media. Alternatively, it has been proposed that hemorrhage from vasa vasorum into a media weakened by cystic medial necrosis initiates stress on the intima, which in turn leads to the intimal tear. Dissection in the media occurs within seconds and separates the inner two thirds of the aorta from the outer third. Because the outer wall of the false channel of the dissecting aneurysm is thin, hemorrhage into the extravascular space-including the pericardium, mediastinum, pleural space and retroperitoneum-frequently causes death. Loss of one or more arterial pulses is common, and a murmur of aortic regurgitation is often present. Whereas many patients suffer from hypertension, hypotension is an ominous sign, suggesting aortic rupture. Superficial varicosities of leg veins are very common and usually involve the saphenous system. They vary from a trivial knot of dilated veins to disabling distention of the whole venous system of the leg. Syphilitic aneurysms mainly affect the ascending aorta, where microscopic examination shows endarteritis and periarteritis of the vasa vasorum (see Chapter 9 for additional details). Gender: Among 30- to 50-year-olds, women are more often affected by varicose veins than men, particularly those who have experienced pregnancy. Heredity: There is a strong familial predisposition to varicose veins, possibly due to inherited configurations or structural weakness of the walls or valves of the veins. Posture: Leg vein pressure is 5 to 10 times higher when a person is erect rather than recumbent. As a result, the incidence of varicose veins and its complications are greater in people whose occupations require them to stand in one place for long periods. Obesity: Excessive body weight increases the incidence of varicose veins, possibly because of increased intra-abdominal pressure or poor support provided by the subcutaneous fat to vessel walls. Thinning due to dilation is present in some areas, whereas others are thickened by smooth muscle hypertrophy, subintimal fibrosis and incorporation of mural thrombi into the wall. Valvular deformities of the veins consist of thickening, shortening and rolling of the cusps. They may develop in the aortic wall or in cerebral vessels during septicemia, most commonly due to bacterial endocarditis. Severe varicosities may lead to alterations in the skin drained by the affected veins, termed stasis dermatitis. Surgical intervention is mandated if the overlying skin has ulcerated or if the patient has spontaneous bleeding or extensive thrombosis (which may progress to pulmonary embolism). As collateral lymphatic routes are abundant, lymphedema (distention of tissue by lymph) usually occurs only when major trunks, most commonly in the axilla or groin, are obstructed. Prolonged lymphatic obstruction causes progressive dilation of lymphatic vessels, termed lymphangiectasia, and overgrowth of fibrous tissue. The term elephantiasis describes a lymphedematous limb that has become grossly enlarged. An important cause of elephantiasis in the tropics is filariasis, in which a parasitic worm invades the lymphatics (see Chapter 9). It usually affects only one limb, but it may be more extensive and may involve the eyelids and lips. Affected tissues show hugely dilated lymphatic channels, and the entire area appears honeycombed or spongy. Hemorrhage from esophageal varices is one of the most common causes of death in cirrhosis. Phlebothrombosis is the term for venous thrombosis that occurs without an initiating infection or inflammation. It is most frequent in deep leg veins and can be a major threat to life because of pulmonary embolization (witness the well-known phenomenon of sudden death with ambulation after surgery). Almost any virulent pathogen can cause acute lymphangitis, but -hemolytic streptococci (S. Painful subcutaneous red streaks, often accompanied by tender regional lymph nodes, characterize acute lymphangitis. The evidence favoring hamartoma includes (1) the lesion is present at birth, (2) it grows only as the rest of the body grows and remains limited in size and (3) after growth ceases, it usually remains unchanged indefinitely in the absence of trauma, thrombosis or hemorrhage. The most common sites are skin, subcutaneous tissues, mucous membranes of lips and mouth and internal viscera, including spleen, kidneys and liver. Juvenile hemangiomas contain packed masses of capillaries separated by connective tissue stroma. Occasionally, they are encountered in the brain, where they may slowly enlarge and cause neurologic symptoms. A cavernous hemangioma is a red-blue, soft, spongy mass, with a diameter of up to several centimeters. Unlike the capillary hemangioma, a cavernous hemangioma does not regress spontaneously. Large endothelial-lined, bloodcontaining spaces are separated by sparse connective tissue. Cavernous hemangiomas can undergo a variety of changes, including thrombosis and fibrosis, cystic cavitation and intracystic hemorrhage. Two or more tissues may be involved, such as skin and nervous system or spleen and liver. Sturge-Weber syndrome involves a developmental disturbance of blood vessels in the brain and skin. This pattern is reflected in the location of glomus tumors at these sites, typically in a subungual location where they are often exquisitely painful. The two main histologic components are branching vascular channels in a connective tissue stroma and aggregates or nests of the specialized glomus cells. The latter are regular, round-to-cuboidal cells that reveal typical smooth muscle cell features by electron microscopy. The epithelioid or histiocytoid variant displays endothelial cells with considerable eosinophilic, often vacuolated, cytoplasm. Surgical removal is generally curative, but about one fifth of patients develop metastases. Spindle cell hemangioendothelioma occurs principally in males of any age, usually in the dermis and subcutaneous tissue of the distal extremities. It features vascular, endothelial-lined spaces into which papillary projections extend. They are normal neuromyoarterial receptors that are sensitive to temperature and regulate arteriolar flow. Glomus Malignant Tumors of Blood Vessels Malignant vascular neoplasms are rare and sometimes arise in preexisting benign tumors. Eventually, most lesions enlarge to become pale gray, fleshy masses without a capsule. The latter display frequent mitoses, pleomorphism and giant cells and tend to be more aggressive. Angiosarcoma of the liver is of special interest because of its association with environmental carcinogens, particularly arsenic (a component of pesticides) and vinyl chloride (used in the production of plastics). Hepatic angiosarcoma was associated with the administration of thorium dioxide, a radioactive contrast medium (Thorotrast) used by radiologists prior to 1950. The earliest detectable changes are atypism and diffuse hyperplasia of the cells lining the hepatic sinusoids. Hepatic angiosarcomas are highly malignant and show both local invasion and metastatic spread. Sporadic Kaposi tumor occurs in elderly men of Eastern European and Mediterranian descent. One form resembles a simple hemangioma with tightly packed clusters of capillaries and scattered hemosiderin-laden macrophages. These lesions may be difficult to distinguish from fibrosarcomas, but the characteristic features of endothelial cells can be demonstrated immunochemically and by electron microscopy. Although Kaposi sarcoma is considered a malignant lesion and may be widely disseminated in the body, it is only exceptionally a cause of death. As demand requires, it can increase its output manyfold, in part because the coronary circulation can augment its blood flow to more than 10 times normal. The ventricles also respond to short-term increases in workload by dilating, in accordance with Starling law of the heart. However, when this compensatory mechanism reaches its limits, the heart no longer provides an adequate supply of blood to peripheral tissues, and the result is congestive heart failure. Damage to the myocardium, caused mostly by ischemic heart disease, also limits the capacity of the left ventricle to pump blood and similarly results in heart failure. Coronary Arteries Supply Blood to the Heart the right and left main coronary arteries originate in, or immediately above, the sinuses of Valsalva of the aortic valve. The infarct is located in the anterior wall and adjacent two thirds of the septum. The left circumflex coronary artery rests in the left atrioventricular groove and supplies the lateral wall of the left ventricle. The right coronary artery travels along the right atrioventricular groove and nourishes the bulk of the right ventricle and posteroseptal left ventricle From these distributions, one can predict the location of infarcts that result from occlusion of any of the three major epicardial coronary arteries. The pattern of dominance is determined by the coronary artery that contributes most of the blood to the posterior descending coronary artery. Ten percent of human hearts display a left-dominant pattern, with the left circumflex coronary artery supplying the posterior descending coronary artery. Thus, as a general rule, the endocardium is most vulnerable to ischemia when flow through a major epicardial coronary artery is compromised. Because capillary networks arising from penetrating arteries do not interconnect, the borders between viable and infarcted myocardium after coronary artery occlusion are distinct. The epicardial portion of each coronary artery fills and expands during systole and empties and narrows during diastole. The intramyocardial arteries have the opposite action and are narrowed by the systolic muscular pressure. As a result, blood flow within myocardium, especially in the subendocardial ventricular regions, is decreased or absent during systole. The fundamental compensatory mechanism is the Frank-Starling mechanism: the cardiac stroke volume is a function of diastolic fiber length and, within certain limits, a normal heart will pump whatever volume is brought to it by the venous circulation. Stroke volume, a measure of ventricular function, is enhanced by increasing ventricular end-diastolic volume secondary to an increase in atrial filling pressure. The most prominent feature of heart failure is the abnormally high atrial filling pressure relative to stroke volume. However, the absolute values of stroke volume and cardiac output are generally well maintained in the failing heart. It develops as a compensatory response to hemodynamic overload, which occurs in association with chronic hypertension or valvular stenosis (pressure overload), myocardial injury, valvular insuffi ciency (volume overload) and other stresses that increase heart workload. A distinction must be made between physiologic hypertrophy of a heart that develops in highly trained athletes and pathologic hypertrophy that occurs in response to injury or overload. These disparities are not well understood and may be related to the fact that the demands of exercise are intermittent, but those of disease Hypertrophic responses feature enlargement of cardiac myocytes through assembly of new sarcomeres. Until recently, this had been thought to occur without an increase in the number of cardiac myocytes, but it is now known that resident cardiac progenitor cells exist, with the potential to contribute to hyperplastic growth (see below). Hypertrophy initially reflects a compensatory and potentially reversible mechanism, but faced with persistent stress, the myocardium becomes irreversibly enlarged and dilated. Myocardial Hypertrophy and Heart Failure the ventricles are compliant in a normal heart and diastolic filling occurs at low atrial pressures. When a heart is injured, the clinical consequences are similar, regardless of the cause of cardiac dysfunction. If the initial impairment is severe, cardiac output is not maintained despite compensatory changes, and the result is acute, life-threatening, cardiogenic shock. When the functional impairment is less, compensatory mechanisms (see below) maintain cardiac output by increasing diastolic ventricular filling pressure and end-diastolic volume. This situation results in the characteristic signs and symptoms of congestive heart failure. Contractile cells respond to mechanical stimuli, such as stretching, by activating receptormediated signaling pathways that produce hypertrophy.

Necrosis of individual tubular epithelial cells is evident both from focal denudation of the tubular basement membrane (arrows) and from the individual necrotic epithelial cells present in some tubular lumina blood pressure medication one kidney generic enalapril 5 mg without a prescription. There is widespread necrosis of proximal tubular epithelial cells arteria dorsalis nasi purchase generic enalapril online, with sparing of distal and collecting tubules (D) pulse blood pressure relationship order enalapril without a prescription. It is more common in females because of a short urethra cardiac arrhythmia chapter 11 cheap enalapril 10 mg without a prescription, lack of antibacterial prostatic secretions and facilitation of bacterial migration by sexual intercourse blood pressure before heart attack order cheap enalapril on-line. Under some circumstances, the residual urine volume (normally 2 to 3 mL) is increased As a result, the bladder contents are not sufficiently diluted with sterile urine from the kidneys to prevent bacterial accumulation. Diabetic glycosuria also predisposes to infection by providing a rich medium for bacterial growth. The intravesicular pressure produced by micturition occludes the distal ureteral lumen, preventing urinary reflux. In many individuals who are particularly susceptible to pyelonephritis, an abnormally short passage of the ureter within the bladder wall is associated with an angle of insertion that is more perpendicular to the mucosal surface of the bladder. Thus, on micturition, rather than occluding the lumen, intravesicular pressure forces urine into the patent ureter. This reflux is powerful enough to force the urine into the renal pelvis and calyces. The simple papillae of the central calyces are convex and do not readily admit reflux urine By contrast, the concave shapes of peripheral compound papillae allow easier access to the collecting system. However, if the pressure is prolonged, as in obstructive uropathy, even simple papillae are eventually vulnerable to the retrograde entry of urine. From the collecting tubules, bacteria gain access to the interstitial tissue and other tubules of the kidney. Anatomical features of the bladder and kidney in pyelonephritis caused by ureterovesical reflux. In the normal bladder, the distal portion of the intravesical ureter courses between the mucosa and the muscularis, forming a mucosal flap. On micturition, the elevated intravesicular pressure compresses the flap against the bladder wall, thereby occluding the lumen. Persons with a congenitally short intravesical ureter have no mucosal flap because the angle of entry of the ureter into the bladder approaches a right angle. By contrast, the peripheral compound papillae are concave and permit entry of refluxed urine. In addition to ascending through urine, bacteria and other pathogens can gain access to the renal parenchyma through the circulation. For example, gram-positive organisms, such as staphylococci, can disseminate from an infected valve in bacterial endocarditis and establish a focus of infection in the kidney. Microscopically, the parenchyma, particularly the cortex, typically shows extensive focal destruction by the inflammatory process, although vessels and glomeruli often are preferentially preserved. Inflammatory infiltrates mainly contain neutrophils, which often fill tubules and especially collecting ducts. In severe cases of acute pyelonephritis, necrosis of the papillary tips may occur or infection may extend beyond the renal capsule to cause a perinephric abscess. Most infections involve only a few pyelonephritis include fever, chills, sweats, malaise, flank pain and costovertebral angle tenderness. Differentiating upper from lower urinary tract infection is often clinically difficult, but the finding of leukocyte casts in the urine supports a diagnosis of pyelonephritis. This process results in the distinctive gross appearance of a broad depressed area of cortical fibrosis and atrophy overlying a dilated calyx (caliectasis). Only chronic pyelonephritis and analgesic nephropathy produce a combination of caliectasis with overlying corticomedullary scarring. Microscopically, the scars have atrophic dilated tubules surrounded by interstitial fibrosis and infiltrates of chronic inflammatory cells. Such tubules, which are "pinched-off" spherical segments, resemble colloid-containing thyroid follicles, a pattern called "thyroidization. Urinalysis shows leukocytes, and imaging studies reveal caliectasis and cortical scarring. In chronic pyelonephritis caused by reflux or obstruction, the medullary tissue and overlying cortex are preferentially injured by recurrent acute and chronic inflammation. There is marked dilation of calyces (caliectasis) caused by inflammatory destruction of papillae, with atrophy and scarring of the overlying cortex. A light micrograph shows tubular dilation and atrophy, with many tubules containing eosinophilic hyaline casts resembling the colloid of thyroid follicles (so-called thyroidization). Possibilities include direct nephrotoxicity or ischemic damage as a result of drug-induced vascular changes, or both. The urine contains erythrocytes, leukocytes (including eosinophils) and sometimes leukocyte casts. Tubular defects are common, including sodium wasting, glucosuria, aminoaciduria and renal tubular acidosis. Most patients recover fully within several weeks or months if the drug is discontinued. At the acidic pH typical of urine, the light chains bind to Tamm-Horsfall glycoproteins, which are secreted by distal tubular epithelial cells and form casts. Renal dysfunction results from the toxic effects of free light chains on tubular epithelial cells and obstruction from the casts. Early parenchymal changes are confined to the papillae and inner medulla and consist of focal thickening of tubular and capillary basement membranes, interstitial fibrosis and focal coagulative necrosis. Eventually, the entire papilla becomes necrotic (papillary necrosis), often remaining in place as a structureless mass. These casts are brightly eosinophilic and glassy (hyaline) and often have fractures and angular borders. Casts may elicit foreign body reactions, with macrophages and multinucleated giant cells. Interstitial chronic inflammatory infiltrates, as well as interstitial edema, typically accompany the tubular lesions. Focal calcium deposits (nephrocalcinosis) are often noted in the fibrotic interstitium of the tubules. Neutrophils are rare, and their presence should raise suspicion of pyelonephritis or hematogenous bacterial infection. Foci of granulomatous inflammation may be present, especially in the later phase of the disease. Proximal and distal tubules are focally invaded by white blood cells ("tubulitis"). For example, chemotherapy for malignant neoplasms results in a sudden increase in blood uric acid because of the massive necrosis of cancer cells (tumor lysis syndrome). Acute renal failure reflects the obstruction of the collecting ducts by precipitated crystals of uric acid, a result of increased concentrations of uric acid in the acidic pH of the urine. Conditions that interfere with excretion of uric acid can also result in hyperuricemia Histologically, the tubular deposits appear amorphous, but in frozen sections, birefringent crystals are apparent. Penetration of collecting ducts by uric acid crystals may provoke a foreign-body giant cell reaction. The basic disease process of chronic urate nephropathy is similar to that of the acute form, but the prolonged course results in more substantial deposition of urate crystals in the interstitium, interstitial fibrosis and cortical atrophy. Although histologic renal lesions are found in most persons with chronic gout, fewer than half show significant compromise of renal function. Until recently, most kidney stones required surgical removal, but ultrasonic disintegration (lithotripsy) and endoscopic removal are now effective. Renal Stones (Nephrolithiasis and Urolithiasis) Nephrolithiasis and urolithiasis are stones within the collecting system of the kidney (nephrolithiasis) or elsewhere in the collecting system of the urinary tract (urolithiasis). They vary in size from gravel (1 mm in diameter) to large stones that dilate the entire renal pelvis. Although they may be well tolerated, in some cases, they result in severe hydronephrosis and pyelonephritis. In the presence of urea-splitting bacteria, usually Proteus or Providencia species, the resulting alkaline urine favors precipitation of magnesium ammonium phosphate (struvite) and calcium phosphate (apatite). Infection stones occasionally fill the pelvis and calyces to form a cast of these spaces, referred to as a staghorn calculus. Bilateral urinary tract obstruction has led to conspicuous dilation of the ureters, pelves and calyces. Eventually, the proximal tubules become widely dilated, and loss of tubules is common. Grossly, progressive dilation of the renal pelvis and calyces occurs, and atrophy of the renal parenchyma ensues. In the presence of hydronephrosis, the kidney is more susceptible to pyelonephritis, which causes additional injury. The major obstacle is immunologic rejection, but recurrence of the disease that destroyed the native kidneys and nephrotoxicity from immunosuppressive drugs also injure the renal allograft. It is the most frequent abdominal solid tumor in children, with a prevalence of 1 in 10,000. Histologically, the tumor is composed of elements that resemble normal fetal tissue. Although most Wilms tumors contain all three elements in varying proportions, they occasionally contain only two elements or even only one. The component corresponding to blastema is composed of small ovoid cells with scanty cytoplasm, growing in nests, and trabeculae. The stroma between the other elements is composed of spindle cells, which are mostly undifferentiated but sometimes display smooth muscle or fibroblast differentiation. Additional manifestations include abdominal pain, intestinal obstruction, hypertension, hematuria and symptoms of traumatic tumor rupture. A number of histologic and clinical parameters have been used with varying success to predict the behavior of Wilms tumors. A cross-section of a pale tan neoplasm attached to a residual portion of the kidney. This photomicrograph of the tumor shows highly cellular areas composed of undifferentiated blastema, loose stroma containing undifferentiated mesenchymal cells and immature tubules. It is typically yellow-orange and often shows conspicuous focal hemorrhage and necrosis. Photomicrograph showing islands of neoplastic cells with abundant clear cytoplasm. McCue the ureters, urinary bladder and the urethra-also known as the lower urinary tract-form the outflow part of the urinary system. They do not usually cause clinical problems but on occasion may predispose to obstruction and urinary tract infections. The most important developmental anomalies include agenesis (associated with kidney agenesis, see Chapter 16), ectopia, duplications, obstructions and dilations. Bilateral agenesis of ureters and kidneys, a feature of Potter syndrome, is incompatible with extrauterine life (see Chapter 16). The lower orifices of ectopic ureters can be found in many anomalous places, such as the midportion of the urinary bladder, seminal vesicles, urethra or vas deferens. There are usually two parallel ureters, each with its own renal pelvis and separate vesical orifice. Bifid ureters (subdivided by a septum) and many variations of this anomaly can be encountered, but most are not clinically significant. This form of hydronephrosis is often associated with other urinary tract anomalies and, in some cases, with agenesis of the contralateral kidney. The resulting stagnation of urine (hydroureter) is typically associated with progressive hydronephrosis, ultimately leading to renal failure. Transitional cell carcinoma of renal pelvis Blood clot Staghorn calculus Ureteral stone Transitional cell carcinoma of ureter Retroperitoneal fibrosis Ureteritis and Ureteral Obstruction Ureteritis is an inflammation of the ureters. It is a complication of descending infections of kidneys or ascending infections if there is vesicoureteric reflux. Ureteritis is often associated with ureteral obstruction, which may be either intrinsic or extrinsic. Ureteral obstruction may also result from diseases that involve the urinary bladder, prostate and urethra, for example, bladder cancer in the vicinity of the ureteral orifice or bladder neck, neurogenic bladder and prostatic hyperplasia. Proximal causes of ureteral obstruction tend to be unilateral, whereas more distal causes, such as prostatic hyperplasia, lead to bilateral hydronephrosis, with the possibility of renal failure in untreated cases. Pregnancy Tumors of the Renal Pelvis and Ureter Tumors of the renal pelvis and ureter resemble those of the urinary bladder except that they are much less common. The etiologic factors associated with epithelial tumors of the renal pelvis and ureter are similar to those observed in bladder cancer (see below). Exstrophy of the bladder results in exposure of the posterior bladder wall to the exterior and transforms the bladder into a cup-like organ that cannot hold urine. The posterior wall of the bladder exposed to mechanical injury undergoes squamous or glandular metaplasia and is prone to frequent infection. Although exstrophy can be surgically repaired, the metaplastic mucosa has an increased risk of malignant transformation. In fact, the incidence of bladder cancer is increased even in persons who have lived for 50 to 60 years after surgical repair of exstrophy. It is the most common urinary tract infection and is often a nosocomial infection in hospitalized patients. Factors related to bladder infection include the age and gender of the patient, presence of bladder calculi, bladder outlet obstruction, diabetes mellitus, immunodeficiency, prior instrumentation or catheterization, radiation therapy and chemotherapy. The risk of cystitis is increased in females because of a short urethra, especially during pregnancy. Bladder outlet obstruction secondary to prostatic hyperplasia predisposes men to cystitis. Virtually unknown in the Western world, schistosomiasis as a cause of cystitis is common in North Africa and the Middle East, where Schistosoma haematobium is endemic (see Chapter 9). Focal petechial mucosal hemorrhages (hemorrhagic cystitis) are often seen in acute bacterial cystitis.

It occurs most commonly in Mediterranean countries where it is a leading cause of sudden death in young people (35 years of age) arrhythmia types generic enalapril 10 mg mastercard. It typically affects the right ventricular free wall pulse pressure explained buy generic enalapril on line, although left dominant and biventricular forms are recognized blood pressure kiosk for sale buy enalapril american express. The characteristic pathologic features are variable degrees of degeneration of cardiac myocytes and replacement by fat and fibrous tissue blood pressure chart low 5 mg enalapril purchase with amex. This section of the right ventricular free wall shows that much of the myocardium has been replaced by mature adipose tissue and fibrosis such that only subendocardial muscle bundles remain blood pressure chart age buy enalapril 5 mg with mastercard. The heart has been opened to show striking asymmetric left ventricular hypertrophy. A section of the myocardium shows the characteristic myofiber disarray and hyperplasia of interstitial cells. Endomyocardial fibrosis leads to progressive myocardial failure and has a poor prognosis, although survival for as long as 12 years has been reported. It is usually encountered in men in the fifth decade and is often accompanied by a rash. Endomyocardial disease is suspected to result from myocardial injury produced by eosinophils, possibly mediated by cardiotoxic granule components. Many cases of restrictive cardiomyopathy are classified as idiopathic, with interstitial fibrosis as the only histologic abnormality. Amyloidosis the heart is affected in most forms of generalized amyloidosis (see Chapter 23). Microscopically, amyloid accumulation is most prominent in interstitial, perivascular and endocardial regions. Endocardial involvement is common in the atria, where nodular endocardial deposits often impart a granular appearance and gritty texture to the endocardial surface. Infiltration of the conduction system can result in arrhythmias, and sudden cardiac death is not unusual. The functional significance of senile cardiac amyloidosis is often minimal, and it is usually an incidental finding at autopsy. On cut section of the ventricle, endocardial fibrosis spreads into the inner one third to one half of the wall. When the right ventricle is involved, the entire cavity may exhibit endocardial thickening, which may penetrate as far as the epicardium. Storage Diseases the various lysosomal storage diseases are discussed in detail in Chapter 6. The functional changes are those of a restrictive type of cardiomyopathy, and the usual cause of death is cardiac failure. Cardiac disease results from lysosomal accumulation of mucopolysaccharides (glycosaminoglycans) in various cells. In general, pseudohypertrophy of the ventricles develops, and contractility gradually diminishes. The coronary arteries may Endomyocardial Disease Endomyocardial disease comprises two geographically separate disorders. The malady is also occasionally seen in other tropical and subtropical regions of the world. The degree of iron deposition in the heart varies and only roughly correlates with that in other organs. Cardiac involvement has features of both dilated and restrictive cardiomyopathy, with systolic and diastolic impairment. Congestive heart failure occurs in as many as one third of patients with hemochromatosis. The brown color seen on gross examination correlates with iron deposition in cardiac myocytes. Interstitial fibrosis is invariable, but its extent does not correlate well with the degree of iron accumulation. However, the severity of myocardial dysfunction seems to be proportional to the quantity of iron deposited. Almost all rhabdomyomas are multiple and involve both ventricles and, in one third of cases, the atria as well. In half of cases, the tumor projects into a cardiac chamber and obstructs the lumen or valve orifices. The tumor appears as a glistening, gelatinous, polypoid mass, usually 5 to 6 cm in diameter, with a short stalk. Microscopically, cardiac myxoma has a loose myxoid stroma containing abundant proteoglycans. Polygonal stellate cells are found within the matrix, occurring singly or in small clusters. One third of patients with myxomas of the left atrium or left ventricle die from tumor embolization to the brain. Microscopically, tumor cells show small central nuclei and abundant glycogenrich clear cytoplasm, in which fibrillar processes containing sarcomeres radiate to the margin of the cell ("spider cell"). Still, only a minority of patients with these tumors will show cardiac metastases. Of all tumors, the one most likely to metastasize to the heart is malignant melanoma. Pericarditis associated with myocardial infarction and rheumatic fever is discussed above. However, rapid accumulation of as little as 150 to 200 mL of pericardial fluid or blood may significantly increase intrapericardial pressure and restrict diastolic filling, especially of the right ventricle. Cardiac tamponade is the syndrome produced by the rapid accumulation of pericardial fluid, which restricts the filling of the heart. The most common form is fibrinous pericarditis, in which the normal smooth glistening appearance of the pericardial surfaces becomes replaced by a dull, granular fibrin-rich exudate. The rough texture of the inflamed pericardial surfaces produces the characteristic friction rub heard by auscultation. The effusion fluid in fibrinous pericarditis is usually rich in protein, and the pericardium contains primarily mononuclear inflammatory cells. Bacterial infection leads to a purulent pericarditis, in which the pericardial exudate resembles pus and contains many neutrophils. Idiopathic or viral pericarditis is a self-limited disorder, although it may infrequently lead to constrictive pericarditis. Serous pericardial effusion is often a complication of an increase in extracellular fluid volume, as occurs in congestive heart failure or the nephrotic syndrome. Chylous effusion (fluid containing chylomicrons) results from a communication of the thoracic duct with the pericardial space secondary to lymphatic obstruction by tumor or infection. The most common cause is ventricular free wall rupture at the site of a myocardial infarct. Less frequent causes are penetrating cardiac trauma, rupture of a dissecting aneurysm of the aorta, infiltration of a vessel by tumor or a bleeding diathesis. The hemodynamic consequences range from a minimally symptomatic condition to abrupt cardiovascular collapse and death. As the pericardial pressure increases, it reaches and then exceeds central venous pressure, thereby limiting return of blood to the heart. Acute cardiac tamponade is almost invariably fatal unless the pressure is relieved by removing pericardial fluid, by either needle pericardiocentesis or surgical procedures. In most cases, the cause of acute pericarditis is obscure and (as in myocarditis) is attributed to an undiagnosed viral infection. The heart of a patient who died in uremia displays a shaggy, fibrinous exudate covering the visceral pericardium. The condition is infrequent today and, in developed countries, is predominantly idiopathic. Prior radiation therapy to the mediastinum and cardiac surgery account for more than one third of cases. Constrictive pericarditis may follow tuberculous infection, which is still the major cause in underdeveloped regions. Cancer of the lung, mostly related to smoking, remains the most common cause of cancer-related death in the United States, killing more than 160,000 persons per year. Chronic obstructive pulmonary disease, also frequent in smokers, is responsible for at least 120,000 deaths per year in the United States. The lung is smaller than normal, owing to the presence of fewer acini or a decrease in their size. The lesion may be accompanied by hypoplasia of the bronchi and pulmonary vessels if the insult occurs early in gestation, as in congenital diaphragmatic hernia. The lesion usually affects one lobe of the lung and consists of multiple cyst-like spaces, which are lined by bronchiolar epithelium and separated by loose fibrous tissue. Some patients with congenital cystic adenomatoid malformation have other congenital anomalies. In the newborn, a bronchogenic cyst may compress a major airway and cause respiratory distress. Secondary infection of the cyst in older patients may lead to hemorrhage and perforation. Airway Infections are Caused by Diverse Organisms the agents causing pulmonary infections are discussed in detail in Chapter 9. Many infectious agents that involve the intrapulmonary airways tend to affect the more peripheral airways (bronchiolitis). All are more serious in malnourished children and populations not ordinarily exposed to these agents. Severe symptomatic illnesses with these agents are more commonly encountered in infants and children, and recovery is the rule. Bronchioles may become obliterated or occluded by loose fibrous tissue (obliterative bronchiolitis). It is three to four times as common in males as in females and is associated with other anomalies in two thirds of patients. In older children, it may come to medical attention because of recurrent bronchopulmonary infections. For many years, it was considered a congenital malformation, but it is now believed that at least some cases are acquired subsequent to chronic inflammation and recurrent infections. On gross examination, the sequestered pulmonary tissue shows the result of chronic recurrent pneumonia, with end-stage fibrosis and honeycomb cystic changes. Microscopically, the cystic spaces are mostly lined by cuboidal or columnar epithelium, and the lumen contains foamy macrophages and eosinophilic material. Interstitial chronic inflammation and hyperplasia of lymphoid follicles is often prominent. The wall of this bronchiole shows an intense chronic inflammatory infiltrate with local extension into the surrounding peribronchial tissue. Severe overdistention may be found without obvious bronchiolar obstruction, possibly due to displacement of surfactant from the bronchiolar surface. Similar to adenovirus, it may result in bronchiolar obliteration and bronchiectasis. With the advent of a pertussis vaccine, the disease has become rare in the United States, but the disease is still a problem in nonvaccinated populations. Recent increase in the frequency of disease in the United States has been linked to failure to vaccinate and to a newly introduced vaccine, which has a lower frequency of side effects, but produces more limited immunity. Bronchocentric granulomatosis can also be a manifestation of rheumatoid arthritis, ankylosing spondylitis and granulomatosis with polyangiitis (formerly Wegener granulomatosis). Patients with bronchocentric granulomatosis of either the allergic or nonallergic type generally respond well to corticosteroid therapy. Constrictive Bronchiolitis May Obliterate the Airway Constrictive (obliterative) bronchiolitis is an uncommon disorder in which an initial inflammatory bronchiolitis is followed by bronchiolar scarring and fibrosis, resulting in constrictive narrowing and eventually complete obliteration of the airway lumen. Oxidants derive from the action of sunlight on automobile exhaust fumes and are important in major urban areas that have temperature inversions. The effects of low concentrations of these agents on normal persons are uncertain, but in persons with chronic pulmonary disease, the situation is different. Air pollution may exacerbate symptoms in asthmatic persons and in those with established respiratory disease. In high concentrations such as encountered in industrial accidents, irritant gases produce serious morphologic and functional effects. Silo workers inhaling high concentrations of the gas develop a form of lung injury known as silo-filler disease. Most patients recover but some develop progressive bronchiolitis obliterans and may die of respiratory failure. Secondary inflammation may lead to extensive bronchiectasis, in part from bronchiolar obliteration and in part from direct damage to the bronchi. Bronchial Obstruction Leads to Atelectasis Bronchial obstruction in adults is most often the consequence of the endobronchial extension of primary lung tumors, although mucinous plugs, aspirated gastric contents or foreign bodies may be responsible, especially in children. Areas distal to the obstruction are also susceptible to pneumonia, pulmonary abscess and bronchiectasis (see below). If the air supply is obstructed, the loss of gas from the alveoli to the blood causes collapse of the affected region. Atelectasis is an important postoperative complication of abdominal surgery, occurring because of (1) mucus obstruction of a bronchus and (2) diminished respiratory movement resulting from postoperative pain. Although atelectasis is usually caused by bronchial obstruction, it may also result from direct compression of the lung Such pressure may seriously compromise Bronchocentric Granulomatosis Usually Reflects Allergic Responses to Infection Bronchocentric granulomatosis refers to nonspecific granulomatous inflammation centered on bronchi or bronchioles. The histologic pattern can be seen in a number of clinical settings and is not a distinct clinical entity. The principal inherited conditions associated with generalized bronchiectasis are cystic fibrosis, the dyskinetic ciliary syndromes, hypogammaglobulinemias and deficiencies of specific immunoglobulin (Ig)G subclasses. Kartagener syndrome is one of the immotile cilia (ciliary dyskinesia) syndromes and comprises the triad of dextrocardia (with or without situs inversus), bronchiectasis and sinusitis. Other dyskinetic ciliary syndromes include radial spoke deficiency("Sturgess syndrome") and absence of the central doublet of cilia. In these diseases, cilia are deficient throughout the body, with resultant male and female sterility.

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