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Osagie K. Obasogie

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The most effective management of paraneoplastic syndromes in the setting of hematologic malignancies remains the treatment of the underlying malignancy spasms spasticity muscle cheap 500 mg mefenamic visa. The following are paraneoplastic syndromes commonly associated with hematologic disorders muscle relaxant soma buy generic mefenamic 250 mg on line, grouped by organ system in which the manifestations occur back spasms 9 months pregnant buy generic mefenamic 500 mg on line. These resemble comparable tumors elsewhere spasms from alcohol buy 500 mg mefenamic mastercard, clinically and pathologically muscle relaxant list order 500 mg mefenamic amex, and include carcinoids (typical and atypical) and carcinomas (small and large cell). They tend to invade locally and metastasize widely, although they may be cured by local excision if they are well circumscribed. While 1/3 of these patients show Cushing syndrome, carcinoid syndrome is exceedingly rare. Most thymic carcinoids are atypical (intermediate category) with frequent mitoses and/or necrosis. The antibody specificity is against red blood cell antigens, owing to immune dysregulation resulting in the loss of tolerance to self-antigens (in this case, red cell antigens) in the setting of malignancy. If drugs, infections or connective tissue diseases are ruled out, evaluation for a lymphoproliferative disorder needs to be done. Paraneoplastic leukocytosis has been reported in different malignancies of lung, gastrointestinal and genitourinary tract, multiple myeloma, Hodgkin lymphoma and anaplastic large cell lymphoma. Although some studies claimed that the presence of paraneoplastic leukocytosis with malignancies portends a poor prognosis, it is not clear if the association of paraneoplastic leukocytosis and lymphomas has the same impact on prognosis. Eosinophilia without leukocytosis has been described in Hodgkin lymphoma and T-cell lymphoma. Histopathologic evaluation reveals intraepidermal acantholysis, necrotic keratinocytes and vacuolar interface changes. Direct immunofluorescence shows intercellular and basement membrane staining for IgG and complement. Indirect immunofluorescence detects serum antibodies that bind to cell surfaces of stratified squamous epithelia. Sweet syndrome is an acute febrile neutrophilic dermatosis characterized by abrupt onset of papular skin lesions, accompanied by systemic symptoms: fever, arthralgia, malaise, headache and myalgia. Laboratory abnormalities, if present, consist of elevated erythrocyte sedimentation rate and peripheral leukocytosis with neutrophilia. As a paraneoplastic syndrome preceding or accompanying hematologic malignancies, Sweet syndrome is seen mostly in acute myeloid leukemia and myelodysplastic syndromes. It occurs as well, albeit less commonly, in patients with lymphoid malignancies (hairy cell leukemia, Hodgkin and non-Hodgkin lymphomas). Pyoderma gangrenosum is an ulcerative skin disease, most frequently associated with inflammatory bowel disease and rheumatoid arthritis. When associated with myelodysplastic syndrome, myeloma or leukemia, the presentation can be atypical, with vesiculobullous lesions and atypical distribution. Vasculitides, which manifest as acute-onset rashes, can be paraneoplastic manifestations of malignancies including myeloid leukemias, lymphomas and hairy cell leukemia. In addition, ocular (conjunctivitis), lung (in the form of bronchiolitis obliterans) and nervous system involvement can occur. The disease, immunologic in nature, is initiated by an occult or overt neoplasm, which elicits an immune response in the form of autoantibody production. The autoantibodies are directed against cell surface adhesion molecules (mainly plakin family proteins and desmogleins). Skin biopsy in a patient with Sweet syndrome, which developed clinically 4 months before myelodysplastic syndrome became evident. There is a dense neutrophilic infiltrate in the upper and middermis, sparing the epidermis and without evidence of vasculitis. If antibodies are not found, the differential diagnosis is extensive, since each of the following disorders can be caused by nonneoplastic conditions such as toxins, infections, vitamin deficiencies and metabolic or autoimmune disorders. Paraneoplastic cerebellar degeneration starts with dizziness, vertigo, ataxia and dysarthria. Limbic encephalitis presents with short-term memory loss, seizures, confusion, sleeping problems, psychiatric symptoms, irritability or depression. Although this condition is more common in nonhematopoietic tumors (non­ small cell lung cancer), it may also be seen in lymphomas, both Hodgkin (associated with anti-Tr antibodies) and nonHodgkin (serum anti-Ma2 antibodies). Paraneoplastic encephalomyelitis is an immune-mediated inflammatory disorder that presents as a subacute sensory neuronopathy. Paraneoplastic involvement of the peripheral nervous system, although rare, can occur in lymphomas. Careful differential diagnosis is important since neuropathies due to direct root infiltration by tumor, amyloid deposition or chemotherapy-induced neuropathy are not infrequent. Examples of these include cutaneous leukocytoclastic vasculitis, which is the most common vasculitis associated with hematologic malignancies. Others (polyarteritis nodosa, Churg-Strauss syndrome, microscopic polyangiitis, granulomatous polyangiitis and Henoch-Schönlein purpura) are described in detail in Chapter 17. The mechanisms are either secretion of parathormone-related peptide by tumor cells or excess calcitriol produced by reactive macrophages infiltrating neoplastic lymph nodes. At the ultrastructural level (electron microscopy), glomerular epithelial cells show alterations of their foot processes, which normally regulate protein permeability. The pathophysiology is incompletely understood but involves dysfunctional podocytes due to cytokine production by infiltrated lymphocytes and macrophages. Glomerular lesions are focal (only some glomeruli are affected) and segmental (portions of the glomeruli are affected), and commonly, tubular atrophy and interstitial fibrosis also occur. As with other paraneoplastic disorders, a direct anatomic relationship between the malignant tumor and the sites of manifestation needs to be excluded. Paraneoplastic polyarthritis, presenting as acute or chronic forms affecting both large and small joints, was described in several cases of B-cell lymphoma and acute leukemias of both lymphoid and myeloid lineage. In most cases, treatment of the underlying malignancy is followed by remission of the rheumatologic disorder. They manifest with severe muscle weakness, skin manifestation, respiratory muscle weakness and dysphagia, and their clinical course parallels the course of malignancy. Sjögren syndrome, which clinically presents with keratoconjunctivitis sicca and xerostomia (dryness of eyes and mouth), can be a paraneoplastic manifestation of non-Hodgkin lymphoma or chronic lymphocytic leukemia. According to some studies, generalized pruritus is caused by malignancy in less than 10% of cases. Although the nervous and endocrine systems use some of the same soluble mediators and sometimes overlap functionally, the endocrine system is unique in its ability to communicate at a distance using soluble mediators, hormones. The term hormone (from the Greek, horman, "set in motion") applies to chemicals secreted by "ductless". Many hormones, such as thyroid hormone, corticosteroids and pituitary hormones, fit this definition. Diseases of the endocrine system may entail too little or too much hormone secretion. Target tissue insensitivity may simulate the clinical picture of hormone underproduction. It sits at the base of the brain in a bony cavity called the sella turcica, within the sphenoid bone. The anterior lobe, or adenohypophysis, arises from the ectoderm, makes up 80% of the gland and is populated by epithelial cells. Along its migration tract, this craniopharyngeal duct may leave intrasphenoidal squamous epithelial rests that may later give rise to tumors known as craniopharyngiomas. The neurohypophysis (posterior lobe) begins as a downward projection of the brain and remains connected to the Hormone-producing cell Responding cell Synaptic. Biological messages may be transmitted by mechanisms other than the classic endocrine pathway via the circulation. Hypothalamohypophysial tract catecholamines, are produced in multiple sites and may act either locally or through the circulation. Other mediators function only in restricted circulation compartments: hypothalamic hormones only act on the pituitary and reach it via portal tributaries without entering the systemic circulation. Finally, many hormones exert their effects in the very tissues that make them, such as müllerian-inhibiting substance. Flanked on either side by the anterior and posterior lobes is a vestigial intermediate lobe, containing a few cystic cavities lined by cuboidal or columnar epithelium and considered as part of the anterior pituitary in humans. It has a complex portal system that originates in the hypothalamus, and a separate arterial and venous blood supply. The hypophysial portal system transports stimulatory and inhibitory hypothalamic-releasing hormones to the anterior pituitary. Venous drainage from the pituitary follows the cavernous sinus to both inferior petrosal sinuses. Axons and unmyelinated nerve fibers from the hypothalamus proceed along the pituitary stalk to the neurohypophysis and are the nerve supply of the posterior lobe. The cells of the anterior pituitary are arranged in cords or nests in a highly vascular stroma. These cells were classically divided into two groups of equal number: stainable and unstainable cells, based on their hematoxylin and eosin (H&E) staining properties. The cytoplasmic granules of stainable cells appeared acidophilic (eosinophilic) (40%), which contain polypeptide hormones, and basophilic (10%), which contain glycoprotein hormones. Basophilic corticotrophs of the pars intermedia may cluster and spread deep into the posterior lobe, a phenomenon called "basophil invasion. Somatotrophs: these acidophilic cells produce and secrete growth hormone and constitute half of the hormone-producing cells of the adenohypophysis. Both of these hormones are formed in neurons in the hypothalamus and transported along axons to the neurohypophysis. A rich network of capillaries surrounds the axon terminals and facilitates hormone release into the vasculature. The effects of hypopituitarism vary with the extent of the loss, specific hormones involved and age of the patient. In general, symptoms relate to deficient function of the thyroid and adrenal glands and the reproductive system. The tumor itself may be functional, but symptoms of hypopituitarism often result because the tumor compresses adjacent tissue. It is often caused by severe hypotension from postpartum hemorrhage or, rarely, without massive bleeding or after normal delivery. The pituitary is particularly vulnerable during pregnancy, because of reduced blood flow associated with its enlargement at this time. The result of the damage to the gland is permanent underproduction of essential pituitary hormones (hypopituitarism). An immunohistochemical stain (inset) demonstrates cells that synthesize growth hormone (somatotropes). The process can be primary if only the gland is involved or secondary if it is associated with an underlying systemic condition such as fungal or tuberculous infection. Involvement of the hypothalamic­pituitary axis in Langerhans cell histiocytosis (see Chapter 26) causes endocrine abnormalities including diabetes insipidus in 5%­50% of patients and panhypopituitarism in 5%­20%. Panhypopituitarism may occur in hemochromatosis (see Chapter 20), owing to iron deposition in the pituitary. This mutation is also associated with Pickardt syndrome, an uncommon form of tertiary hypothyroidism caused by abnormalities in the portal veins connecting the pituitary with the hypothalamus. Mutations are associated with Rieger syndrome, an autosomal dominant condition with variable phenotypic expression including pituitary abnormalities. Laron syndrome occurs mainly in people of Mediterranean origin, such as Sephardic Jews. Clinical presentations are heterogeneous, and most cases are unique to particular families or geographic areas. Kallmann syndrome is usually diagnosed at puberty because of a delay in the appearance of secondary sex characteristics. Most cases are sporadic, but there are familial forms, some of which are X-linked, while others are autosomal dominant or recessive. It is due to a congenitally defective or absent diaphragma sella, which permits transmission of cerebrospinal fluid pressure into the sella. Empty sella syndrome can cause various degrees of pituitary dysfunction and endocrine abnormalities. It has been linked to both pituitary and nonpituitary causes and can result from pituitary gland regression after an injury, surgery or radiation therapy. Endocrine disturbances include hyperprolactinemia, oligomenorrhea or amenorrhea, frank hypopituitarism, acromegaly, diabetes insipidus and Cushing syndrome. They often cause excess secretion of one or more pituitary hormones and corresponding endocrine hyperfunction (Table 27-1). Small, apparently nonfunctioning pituitary adenomas are found incidentally in as many as 27% of adult autopsies. Acquired activating mutations in the stimulatory subunit of the Gs protein that activates adenylyl cyclase have been reported in 40% of growth hormone­secreting pituitary adenomas. Other syndromes associated with pituitary tumors include McCune-Albright and familial acromegaly. This difference in sex distribution is related to the more frequent occurrence of endocrine symptoms in women. Endocrine amyloid (see Chapter 15) and psammoma bodies (calcospherites) occur but are not pathognomonic. A magnetic resonance sagittal view of the brain shows a distinct pituitary tumor (arrow). Since H&E staining properties of the tumor cells do not correlate with the type of hormone secreted, pituitary adenomas are now classified by the hormone(s) they produce.

Medullary cystic disease is autosomal dominant with onset in adolescence and renal failure in adulthood spasms of pain from stones in the kidney mefenamic 250 mg purchase with mastercard. Atrophic tubules with markedly thickened and laminated basement membranes and loss of tubules out of proportion to glomerular loss are early histologic features of the disease spasms left shoulder blade mefenamic 250 mg order with mastercard. Eventually spasms from colonoscopy cheap 250 mg mefenamic with mastercard, corticomedullary cysts may develop spasms leg buy mefenamic 250 mg low cost, and the rest of the parenchyma becomes increasingly atrophic spasms all over body cheap mefenamic 250 mg buy line. Secondary glomerular sclerosis, interstitial fibrosis and nonspecific inflammatory infiltrates dominate the late histologic picture. The gene product, fibrocystin, is found in the primary cilia of the collecting ducts of the kidney, biliary ducts of the liver and exocrine ducts of the pancreas, and it appears to be involved in regulation of cell differentiation, proliferation and adhesion. Interstitial fibrosis and tubular atrophy are common, particularly in children in whom disease presents later. The liver is usually affected by congenital hepatic fibrosis, with fibrous expansion of portal tracts with bile duct proliferation (see Chapter 20). Nephronophthisis is seen in three clinical variants: infantile, juvenile and adolescent. The dilated cortical and medullary collecting ducts are arranged radially, and the external surface is smooth. Symptomatic cases are usually discovered between the ages of 30 and 60 years, presenting with flank pain, dysuria, hematuria or "gravel" in the urine caused by stone formation in the cysts. Although the disease itself does not pose a threat to health, the cysts may predispose to secondary pyelonephritis. Increased glomerular capillary permeability allows loss of protein from plasma into the urine (proteinuria). Proteinuria is caused by many different glomerular diseases and by a variety of mechanisms. Nephrotic syndrome results from primary glomerular diseases unrelated to a systemic disease, or they may be secondary to a systemic disease that affects other organs as well as the kidneys. Diabetic glomerulosclerosis is the most common cause of secondary nephrotic syndrome in adults. Table 22-1 lists the major causes and approximate frequency of the primary nephrotic syndrome in adults and children. Table 22-2 details selected pathologic features of some of these diseases (discussed below). There are important differences in the rates of specific glomerular diseases that cause nephrotic syndrome in adults versus those in children. For example, minimal-change disease is responsible for most (70%) cases of primary nephrotic syndrome in children, but only 15% in adults. They may be solitary or multiple and are usually found in the outer cortex, where they bulge the capsule. After 5 years of dialysis, more than 75% of patients show bilateral cystic kidneys. The cysts are initially lined by flat-to-cuboidal epithelium, but hyperplastic and neoplastic epithelial proliferation may develop within 10 years of initiating dialysis. Nephritic (Glomerulonephritis) Syndrome Is an Inflammatory Disease with Hematuria, Proteinuria and Decreased Glomerular Filtration Rate Hematuria may be microscopic or grossly visible, and proteinuria varies. Glomerular diseases associated with the nephritic syndrome are caused by inflammatory changes in glomeruli. Injury to glomerular capillaries results in spillage of protein and blood cells into the urine (proteinuria and hematuria). The inflammatory damage may also impair glomerular flow and filtration, resulting in renal insufficiency, fluid retention and hypertension. Nephritic manifestations may (1) develop rapidly and result in reversible renal insufficiency (acute glomerulonephritis); (2) progress rapidly, with renal failure that resolves only with aggressive treatment (rapidly progressive glomerulonephritis); or (3) persist for years continuously or intermittently and proceed slowly to renal failure (chronic glomerulonephritis). Some glomerular diseases tend to cause the nephrotic syndrome, but others lead to the nephritic syndrome (Table 22-3). However, except for minimal-change disease (which almost always causes nephrotic syndrome), all glomerular diseases may occasionally cause mixed nephritic and nephrotic manifestations that confound clinical diagnosis. Renal biopsy evaluation is the only means of definitive diagnosis for most glomerular diseases, although clinical and laboratory data may provide presumptive evidence for a specific disease. Immune complexes that deposit from the circulation also activate complement and recruit inflammatory cells. Accurate pathologic diagnosis of glomerular diseases requires examination of renal tissue by light, immunofluorescence and electron microscopy, and integration of these findings with clinical information. Resultant immune complexes in glomerular capillary walls attract leukocytes and activate complement and other humoral inflammatory mediators, resulting in inflammatory injury. Circulating immune complexes may deposit in glomeruli and incite inflammation like that produced when immune complexes form in situ. For example, circulating antibodies can bind to antigens released into the blood by bacterial or viral infection to produce immune complexes. If these complexes escape phagocytosis, they can deposit in glomeruli and incite inflammation. Antineutrophil cytoplasmic autoantibodies cause severe glomerulonephritis with little or no glomerular immunoglobulin deposition. Such patients often have circulating autoantibodies specific for antigens in the cytoplasm of neutrophils, which activate them and so mediate glomerular inflammation. This interaction activates neutrophils and causes them to adhere to microvascular endothelial cells, especially glomerular capillaries. There, they release products that promote vascular inflammation, including glomerulonephritis, arteritis and venulitis. A fourth immunopathology category of glomerulonephritis (C3 glomerulopathy) is mediated by dysregulation of the alternative complement pathway caused either by the genetic absence or dysfunction of complement regulatory proteins. Algorithm demonstrating the integration of pathologic findings with clinical data to diagnose specific forms of primary or secondary glomerulonephritis. Once this determination is made, more specific diagnoses depend on additional clinical or pathologic observations. In general, pathologic features of acute inflammation, such as endocapillary and extracapillary hypercellularity, leukocyte infiltration and necrosis, are more common in disorders characterized mainly as nephritic than in those that are more typically nephrotic. Glomerular crescent formation (extracapillary proliferation) correlates with a more rapidly progressive course. They are, rather, markers of severe injury causing extensive rupture of capillary walls, which allows inflammatory mediators to enter the Bowman space, where they stimulate macrophage infiltration and epithelial proliferation. T-cell lymphomas has led to speculation that minimalchange disease may reflect a disorder of T lymphocytes, possibly involving production of a cytokine that increases glomerular permeability via effects on podocytes. This allows anionic proteins, especially albumin, to pass more easily across capillary walls. Proteinuria leads to hypoalbuminemia, and a compensatory increase in lipoprotein secretion by the liver results in hyperlipidemia. Loss of lipoproteins through glomeruli causes lipids to accumulate in proximal tubular cells, reflected histologically as glassy (hyaline) droplets in tubular epithelial cytoplasm. Such droplets are not specific for minimal-change disease but are seen in any glomerular disease causing nephrotic syndrome. This occurs in almost all cases of nephrotic range proteinuria; it is not specific for minimal-change disease. Immunofluorescence studies for immunoglobulin and complement deposition are most often negative, but there is occasional weak mesangial staining for IgM and the complement component C3. Minimal-Change Disease Causes Nephrotic Syndrome Pathologically, this disease entails effacement of podocyte foot processes. The immune system may be involved: the disease may remit with corticosteroid treatment, and it may occur in association with an allergic disease or a lymphoid neoplasm. Proteinuria is generally more selective (albumin > globulins) than in the nephrotic syndrome caused by other diseases, but there is too much overlap for this to be used as a diagnostic criterion. In this electron micrograph, the podocyte (P) displays extensive effacement of foot processes and numerous microvilli projecting into the urinary space (U). Loss of epithelial foot processes children and in fewer adults with minimal-change disease, proteinuria remits completely within 8 weeks of initiating corticosteroid therapy. If corticosteroids are withdrawn, most patients have intermittent relapses for up to 10 years. A small subgroup of patients has only partial remission with corticosteroid therapy and continues to lose protein in the urine. In the absence of complications, the long-term outlook for patients with minimal-change disease is no different from that of the general population. This condition is characterized predominantly by epithelial cell changes, particularly effacement of foot processes. In all of these settings, glomerular enlargement reflects functional overwork, placing undue stress on podocytes because of their limited proliferative capacity. Apparently, these variants provide protection against African sleeping sickness (trypanosomiasis), which may explain their prevalence in blacks. As in sickle cell disease, this is an example of how a genetic variant can cause a common disease while providing protection against a major infectious disease. Insudation of plasma proteins and lipid gives lesions a glassy appearance, called hyalinosis. Uninvolved glomeruli may look entirely normal, although mild mesangial hypercellularity is occasionally present. This collapsing variant has a poor prognosis, and 1/2 of patients reach end-stage disease within 2 years. Sclerotic segments show increased matrix material, wrinkling and thickening of basement membranes and capillary collapse. Accumulation of electron-dense material in sclerotic segments represents insudative trapping of plasma proteins and corresponds to hyalinosis seen by light microscopy. Immunofluorescence microscopy shows irregular trapping of IgM and C3 in the segmental areas of sclerosis and hyalinosis. Nonsclerotic segments do not stain or do so weakly, usually for IgM and C3 in the mesangium. A different hypothesis proposes that the nephropathy is caused by another virus that has infected the kidney of an immunocompromised person. Capillaries in sclerotic segments collapse, often with adjacent swollen podocytes that have numerous protein droplets. Tubular epithelial atrophy and degeneration are conspicuous; cystically dilated tubules contain proteinaceous casts. By electron microscopy, many tubuloreticular inclusions are seen in endothelial cells, similar to those in lupus nephritis. Membranous Glomerulonephritis Is a Disease of Immune Complex Deposition Membranous glomerulonephritis is a common cause of nephrotic syndrome in adults. It is more common in blacks than in whites and is the leading cause of primary nephrotic syndrome in blacks. Most often, asymptomatic proteinuria begins insidiously and progresses to the nephrotic syndrome. Formation in situ occurs in the animal model of membranous glomerulonephritis called Heymann nephritis, in which rats are immunized with a renal epithelial antigen and develop autoantibodies. Resultant immune complexes are shed into the adjacent subepithelial zone to cause membranous glomerulonephritis. A rare form of neonatal membranous glomerulonephritis is caused by transplacental passage of antibodies that react with an alloantigen on neonatal podocytes (neutral endopeptidase) that is not shared by the mother. Repeated experimental exposure to foreign proteins elicits antibodies, which form circulating immune complexes. These spikes are projections of basement membrane material around subepithelial immune complexes (which do not stain with silver). As disease progresses, capillary lumens narrow, and glomerular sclerosis eventually ensues. Advanced membranous glomerulonephritis cannot be distinguished from other forms of chronic glomerular disease. Atrophy of tubules and interstitial fibrosis parallel the degree of glomerular sclerosis. Silver staining reveals multiple "spikes" diffusely distributed in the glomerular capillary basement membranes. The appearance is produced by the deposition of silver-positive basement membrane material around silver-negative immune complex deposits. This difference may reflect the fact that primary disease is caused by antigens normally present in the subepithelial zone. There is intense staining for terminal complement components, including the membrane attack complex, which participate in inducing glomerular injury, especially to podocytes. Spontaneous remission occurs in 1/4 of patients within 20 years, and 10-year renal survival rate is greater than 65%. Lower survival correlates with male gender, age above 50, proteinuria of more than 6 g/day, extensive glomerular sclerosis and chronic tubulointerstitial disease. Patients with progressive renal failure receive corticosteroids and/ or immunosuppressive drugs. The prognosis is better in children because of a higher rate of permanent spontaneous remission. The glomerulus is slightly enlarged and shows diffuse thickening of the capillary walls. The abnormal metabolic state leads to a general increase in synthesis of basement membrane material in the microvasculature. One hypothesis proposes that increased oxidative injury and abnormal nonenzymatic glycosylation of plasma proteins. Mild mesangial hypercellularity may be present along with the increase in mesangial matrix. Insudated proteins form rounded nodules between the Bowman capsule and the parietal epithelium ("capsular drops") or subendothelial accumulations along capillary loops ("hyaline caps").

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Many liver abnormalities muscle relaxant little yellow house purchase genuine mefenamic on-line, manifested by increased serum liver enzymes spasms chest discount 250 mg mefenamic, hepatomegaly and altered liver histology zoloft spasms buy mefenamic in india, may also complicate obesity spasms piriformis cheap 500 mg mefenamic otc. Specifically muscle relaxant in pregnancy buy discount mefenamic 250 mg, risks for esophageal, gallbladder, pancreatic, breast, renal, uterine, cervical and prostate cancers are all increased. Obesity has also been associated with overexpression of aromatase in adipose tissue within the breast, local production of estrogen and increased breast cancer risk. Obesity increases the risk of osteoarthritis, particularly of weight-bearing joints such as the knees. However, non­weight-bearing joints can also be affected, suggesting mechanisms other than increased mechanical load. Acanthosis nigricans is a velvety, hypertrophic, hyperpigmented lesion, especially at skinfold areas (axillae, nape of the neck). It may be a response to high circulating insulin levels in patients with insulin resistance. Excessive hair growth (hirsutism) can result from increases in circulating androgens in susceptible women. Psychological and social: Obesity has also been associated with impaired quality of life, increased sick leave absences and disability claims and depression. Diabetes Mellitus Almost a century ago, Sir William Osler defined diabetes mellitus as "a syndrome due to a disturbance in carbohydrate metabolism from various causes, in which sugar appears in the urine, associated with thirst, polyuria, wasting and imperfect oxidation of fats. Hence, diabetes mellitus in the modern setting is redefined as "a state of premature cardiovascular death that is associated with chronic hyperglycemia and may also be associated with blindness and renal failure. Adults with diabetes are two to four times more likely to have heart disease or stroke than those without diabetes. Diabetes is a major health problem that affects increasing numbers of people throughout the world. Two major forms are recognized, distinguished by different underlying pathophysiologies. It results from a complex interrelationship between insulin resistance of target tissues and an oversecretion of insulin by the pancreas (see above). This balance may, or may not, be sufficient to control plasma glucose concentrations. Gestational diabetes develops in some pregnant women owing to resistance to the glucose-lowering actions of insulin in pregnancy, combined with a beta cell defect in the pancreas. Diabetes can also occur in other endocrine conditions or drug therapy, especially in Cushing syndrome or during treatment with glucocorticoids. Other rare clinical syndromes entail abnormal glucose metabolism or overt hyperglycemia. As these conditions are uncommon and have well-defined genetic etiologies that differ from the more common forms of diabetes, they will not be considered in detail. Current criteria for the diagnosis of diabetes mellitus are based on abnormal threshold levels for glucose or hemoglobin A1c that are closely associated with the chronic complications of this disorder. In particular, hyperglycemia causes the microvascular changes of diabetic retinopathy and renal glomerular damage. One of the four criteria has to be present for the diagnosis, but some criteria require repeat testing for confirmation. Some of those are commonly referred to as "prediabetes," but the term should be used with caution, because only half of those patients will ultimately develop diabetes. Recently, it has been appearing increasingly in younger adults and adolescents, as severe obesity and lack of exercise become more severe and common in this age group. In a patient with classic symptoms of hyperglycemia or hyperglycemic crisis, a random plasma glucose 200 mg/dL (11. Over 25% of people over 60 have diabetes, and 35% of adults are felt to have prediabetes. Diabetes is also increasing worldwide: in China, for example, it affects about 10% of adults. Diabetes is the leading cause of kidney failure, nontraumatic lower limb amputations and new cases of blindness among American adults. It is also a major factor in heart disease and stroke, and is the 7th leading cause of death. The first "hit" is resistance to the glucose-lowering actions of insulin in its target tissues (liver, skeletal muscle, adipose tissue). This defect alone provokes increased total pancreatic output of insulin and may later be followed by moderate defects in glucose handling, indicative of prediabetes. The second "hit" occurs when increased pancreatic insulin output can no longer compensate for the highly increased demand for insulin to control blood sugar levels. The most important ones are obesity, overnutrition and low levels of physical activity. The expanded visceral fat mass in upper body obesity elaborates several factors that may contribute to insulin resistance for glucose. These changes result in impairments to insulin action in liver and skeletal muscle at the level of the insulin receptor and at postreceptor signaling sites, resulting in a failure of insulin to suppress hepatic glucose production and to promote glucose uptake into muscle. The resulting hyperglycemia is normally countered by increased insulin secretion by pancreatic beta cells. Several mutations in genes that control beta cell development and function have been described. Insulin Resistance for Glucose After a carbohydrate-rich meal, the gut absorbs glucose. This increases blood glucose, which stimulates insulin secretion by pancreatic beta cells. At the same time, insulin suppresses hepatic glucose production by (1) inhibiting glycogenolysis and gluconeogenesis, (2) enhancing glycogen synthesis, (3) blocking the effects of glucagon on the liver and (4) antagonizing glucagon release from the pancreas. As the condition progresses, fasting glucose rises or impaired glucose tolerance develops. In many obese and prediabetic patients, subclinical beta cell dysfunction exists before overt diabetes. Later in the second phase of the disease, release of newly synthesized insulin is faulty. This effect can be reversed, at least in some patients, by restoring good control of glycemia. Incretins are peptides secreted by the gut in response to meals that increase insulin secretion and decrease glucagon secretion. Effects of incretins include (1) enhanced glucose-dependent stimulation of insulin secretion by beta cells, (2) inhibition of glucagon secretion by alpha cells, (3) inhibition of appetite and (4) slowed gastric emptying. Both can improve dramatically with even modest weight loss and exercise, and lifestyle interventions are at the center of clinical management. Metformin is considered an "insulin sensitizer," because it improves glucose uptake by muscle and inhibits hepatic glucose production, although its mechanism of action at a molecular level remains in dispute. Some of their side effects, such as water retention, increased appetite and others, have limited their use. Glucose regulation and metabolic activity during the development of type 2 diabetes mellitus. In some islets, fibrous tissue accumulates, sometimes so much that islets are obliterated. This type of amyloid is composed of a polypeptide molecule known as amylin, which is secreted with insulin by the beta cell. Importantly, as many as 20% of aged nondiabetics also have amyloid in their pancreatic islets, a finding that has been attributed to the aging process itself. Typical patterns of insulin production in response to glucose challenge in normal (blue) and type 2 diabetic (red) patients. Involvement of incretins in regulating the responses of the body to a caloric load. Without insulin, the body switches energy use to a pattern that resembles starvation, regardless of the availability of food. Thus, adipose stores, rather than exogenous glucose, are preferentially metabolized for energy. Oxidation of fat overproduces ketone bodies (acetoacetic acid and -hydroxybutyric acid), which are released into the blood from the liver and lead to metabolic ketoacidosis. Hyperglycemia results from unsuppressed hepatic glucose output and reduced glucose uptake into skeletal muscle and adipose tissue. This, in turn, causes osmotic diuresis, which can lead to dehydration from accompanying loss of body water. Most develop this disease within the first two decades of life, but more and more cases are being recognized in older people. In some older patients, autoimmune beta cell destruction may develop slowly over many years. In many geographical areas, an increased incidence in late fall and early winter suggests seasonal infections as autoimmune triggers (see below). Most newly diagnosed children with this disease have circulating antibodies against components of the beta cells. However, these antibodies are now regarded as responses to beta cell antigens released during destruction of beta cells by cell-mediated immune mechanisms, rather than the cause of beta cell depletion. Patients transplanted with a donor pancreas or a preparation of purified islets must be treated with immunosuppressive drugs. Amyloid deposition (hyalinization) of an islet in the pancreas of a patient with type 2 diabetes mellitus (lower left). Blood vessels adjacent to the islet show the advanced hyaline arteriolosclerosis (arrows) characteristic of diabetes. A lymphocytic inflammatory infiltrate (arrows) is seen in and around the islet (left of bracket). This suggests genetic imprinting involving paternal susceptibility genes or protective intrauterine or other maternal influences. There are differences in risk among different ethnic groups who live in similar environments. Certain proteins may share antigenic determinants with human cell surface proteins and trigger autoreactivity by molecular mimicry. As the disease becomes chronic, islet beta cells become progressively depleted; eventually insulin-producing cells are no longer discernible. Loss of beta cells results in variably sized islets, many of which appear as ribbon-like cords that may be difficult to distinguish from surrounding acinar tissue. The disease develops from an initial genetic susceptibility to defective recognition of beta cell epitopes and ends with essentially complete beta cell destruction in most patients. Patients with islet cell antibodies and normal blood glucose levels are considered to have a state of "pre­type 1 diabetes. Depending on the degree of absolute insulin deficiency, severe ketoacidosis may be preceded by weeks to months of increased urine output (polyuria) and increased thirst (polydipsia). Weight loss in spite of increased appetite (polyphagia) results from unregulated catabolism of body stores of fat, protein and carbohydrate. Thus, control of blood glucose remains the major means by which the development of microvascular diabetic complications can be minimized. It has been more difficult to demonstrate that glucose control can prevent "macrovascular" (large-vessel) complications, meaning atherosclerosis and its sequelae (coronary artery disease, peripheral vascular disease and cerebrovascular disease). Proposed mediators of glucose-induced oxidative damage include nitric oxide, superoxide anions and aldose reductase (see Chapter 1). Nevertheless, antioxidant supplementation does not affect the course of diabetes and atherosclerosis in people. Numerous cellular proteins are modified in this manner, including hemoglobin, components of the crystalline lens and cellular basement membrane proteins. A specific fraction of glycated hemoglobin in circulating red blood cells, hemoglobin A1c, is used routinely to monitor the overall degree of hyperglycemia during the preceding 6­8 weeks. Because glycation of hemoglobin is irreversible, hemoglobin A1c levels serve as a marker for glycemic control. The initial glycation products (known chemically as Schiff bases) are labile and can dissociate rapidly. For example, albumin and immunoglobulin G (IgG) do not normally bind to collagen, but they adhere to glycated collagen. Aldose reductase has a low affinity for glucose, but it generates considerable amounts of sorbitol in tissues when blood glucose is elevated. In the ocular lens, excess sorbitol may simply create an osmotic gradient that causes influx of fluid and consequent swelling. Increased intracellular sorbitol has been linked to decreased myoinositol (a precursor of phosphoinositides), lower protein kinase C activity and inhibition of the plasma membrane sodium pump. However, inhibition of aldose reductase shows no benefit in human clinical trials, so the roles of aldose reductase and sorbitol in the complications of diabetes is unclear. Atherosclerosis Is a Deadly Complication of Diabetes Atherosclerotic heart disease and ischemic strokes account for over half of all deaths among adults with diabetes. The extent and severity of atherosclerotic lesions in mediumsized and large arteries are increased in patients with longstanding diabetes. Diabetes eliminates the usual protective effect of being female, and coronary artery disease develops at a younger age than in nondiabetic people. Moreover, mortality from myocardial infarction is higher in diabetics than in nondiabetics. Atherosclerotic peripheral vascular disease, particularly of the lower extremities, commonly complicates diabetes. Vascular insufficiency may cause ulcers and gangrene of the toes and feet, ultimately necessitating amputation. Diabetes accounts for more than 60% of nontraumatic limb amputations in the United States.

Xanthogranulomatous pyelonephritis is an uncommon form of chronic pyelonephritis that is often caused by diverse pathogens muscle relaxant 500 mg mefenamic 500 mg with visa, such as Proteus spasms lower back mefenamic 250 mg purchase with amex, E muscle relaxant wiki discount mefenamic 500 mg visa. Urinalysis shows leukocytes muscle relaxant 1 generic 500 mg mefenamic overnight delivery, and imaging studies reveal caliectasis and cortical scarring muscle relaxant bodybuilding buy generic mefenamic from india. Analgesic Nephropathy Results from Chronic Overconsumption of Phenacetin Patients with analgesic nephropathy typically have taken more than 2 kg of analgesics, often in combinations, such as aspirin and phenacetin, or aspirin and acetaminophen. Phenacetin most often leads to nephropathy and is banned in many countries, including the United States. Possibilities include direct nephrotoxicity, ischemic damage due to druginduced vascular changes or both. Many tubules contain eosinophilic hyaline casts resembling the colloid of thyroid follicles (so-called thyroidization). The earliest histologic abnormality is a distinctive homogeneous thickening of capillary walls just beneath the transitional epithelium of the urinary tract. The lesion is characterized by a granulomatous reaction, full of foamy histiocytes. Early parenchymal changes are confined to papillae and the inner medulla, and they consist of focal basement membrane thickening of tubules and capillaries, interstitial fibrosis and focal coagulative necrosis. Necrotic areas eventually become confluent, first affecting the corticomedullary junction and then the collecting ducts. Eventually, the entire papilla becomes necrotic (papillary necrosis), often remaining in place as an amorphous mass. Papillae may remain partly attached at the demarcation zone or be completely sloughed. There is secondary tubular atrophy, interstitial fibrosis and chronic inflammation in the overlying cortex. Neutrophils are rare; their presence should raise suspicion of pyelonephritis or hematogenous bacterial infection. Sloughing of necrotic papillary tips into the renal pelvis may result in colic as they pass through the ureters. The immunogen could be the drug itself, the drug bound to certain tissue components, a drug metabolite or a tissue component altered by the drug. There is interstitial edema and infiltration by mononuclear leukocytes, with admixed eosinophils. Proximal and distal tubules are focally invaded by white blood cells ("tubulitis"). Urinalysis shows 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 offending drug is discontinued. Light-Chain Cast Nephropathy May Complicate Multiple Myeloma Light-chain cast nephropathy is renal injury caused by monoclonal immunoglobulin light chains in the urine. However, at the acidic pH typical of urine, these light chains form casts by binding to Tamm-Horsfall glycoproteins that are secreted by distal tubular epithelial cells. Renal dysfunction results from both the toxicity of free light chains for tubular epithelium and obstruction by the casts. They may elicit foreign body reactions, with macrophages and multinucleated giant cells. Interstitial chronic inflammation and edema typically accompany the tubular lesions. Focal calcium deposits (nephrocalcinosis) often occur in the fibrotic tubular interstitium. Urate Crystals Deposit in the Tubules and Interstitium in Urate Nephropathy Any condition with elevated blood levels of uric acid may cause urate nephropathy. Proteinuria, predominantly of immunoglobulin light chains, is usually present, although not necessarily in the nephrotic range. In tumor lysis syndrome, blood uric acid suddenly increases as massive numbers of tumor cells die. Uric acid crystals precipitate in the acidic pH of collecting ducts, obstruction them and causing acute renal failure. Chronic lead intoxication interferes with uric acid secretion by proximal tubules and leads to saturnine gout. The pathogenesis of chronic urate nephropathy is similar to that of the acute form, but because the course is prolonged, more urate deposits in the interstitium, causing interstitial fibrosis and cortical atrophy. It is a focal accumulation of urate crystals surrounded by inflammatory cells, which may appear granulomatous and include multinucleated giant cells. Uric acid stones account for 10% of urolithiasis and occur in 20% of patients with chronic gout and 40% of those with acute hyperuricemia. Although histologic renal lesions occur in most patients with chronic gout, less than 1/2 have significant renal functional impairment. Nephrocalcinosis may impair renal function, especially tubular defects such as poor concentrating ability, salt wasting and renal tubular acidosis. If nephrocalcinosis is caused by hypercalcemia, it is metastatic calcification, whereas calcification at sites of renal parenchymal injury. Acute phosphate nephropathy is a form of nephrocalcinosis that is an uncommon complication of phosphate bowel-cleansing preparations used in patients about to undergo colonoscopy. Pathologically, calcium phosphate deposits in injured distal tubules and collecting ducts, usually accompanied by interstitial fibrosis and chronic inflammation. In patients with nephrocalcinosis caused by hypercalcemia, calcification varies from tiny deposits to grossly and radiologically visible calcium aggregates. These scars reflect parenchymal atrophy and interstitial fibrosis caused by the calcification. Renal tubular basement membrane calcification may be striking, particularly in proximal convoluted tubules. Such deposits also accumulate in the cytoplasm of tubular epithelial cells, which eventually degenerate and are sloughed into the lumens to aggregate as calcified casts. By electron microscopy, the mitochondria of renal tubular epithelial cells contain abundant calcium deposits. Stones vary in composition, depending on geography, metabolic alterations and the presence of infection. They vary in size from gravel (<1 mm) to large stones that dilate the entire renal pelvis. Although they may be well tolerated, in some cases they lead to severe hydronephrosis and pyelonephritis. Larger kidney stones required surgical removal in the past, but ultrasonic disintegration (lithotripsy) and endoscopic removal are now effective. A urinary stone is usually associated with increased blood levels and urinary excretion of its principal component. However, many patients with calcium stones have hypercalciuria without hypercalcemia. Mixed urate and calcium stones are common with hyperuricemia, as urate crystals act as a nidus for calcium salts to precipitate. Bilateral urinary tract obstruction has led to conspicuous dilation of the ureters, pelves and calyces. Calcium oxalate is more common in the United States, whereas in England, calcium phosphate predominates. Calcium oxalate stones are hard and occasionally dark, because they are covered by hemorrhage from the mucosa of the renal pelvis injured by the sharp calcium oxalate crystals. Infection stones: Infection, often with urea-splitting bacteria like Proteus or Providencia spp. Resulting alkaline urine favors magnesium ammonium phosphate (struvite) and calcium phosphate (apatite) precipitation. Infection stones cause frequent complications, such as intractable urinary tract infection, pain, bleeding, perinephric abscess and urosepsis. Uric acid stones: these stones occur in 25% of patients with hyperuricemia and gout, but most patients with uric acid stones have neither (idiopathic urate lithiasis). Cystine stones: these account for only 1% of renal stones overall but are a significant fraction of childhood calculi. Although composed only of cystine, they may be enveloped by a layer of calcium phosphate. Hydronephrotic kidneys are more susceptible to pyelonephritis, adding injury to insult. Many causes of acute obstruction are reversible; thus, prompt recognition is important. However, the transplanted organ is also susceptible to recurrence of the disease that destroyed the native kidneys and to nephrotoxicity from immunosuppressive drugs. Table 22-14 lists distinct, but often coexisting, patterns of antibody-mediated and cellular renal allograft rejection. Renal allograft rejection can be classified on the basis of its clinical course, pathologic features and presumed pathogenesis (Table 22-14). However, an allograft may undergo more than one type of rejection at the same time. Antibody binds endothelial cell antigens, activates complement and thus attracts neutrophils. The cytotoxic effects of complement and neutrophils cause endothelial cells to swell, become vacuolated and lyse. Accumulation of neutrophils in glomerular capillaries portends impending rejection. Neutrophils or mononuclear leukocytes are increased in peritubular and glomerular capillaries, and in tubules. Preformed antibody against recipient antigens causes an immediate in situ reaction, with hemorrhage developing due to vascular necrosis. Staining of peritubular and glomerular capillaries with an anti-C4d antibody showing evidence of complement activation by antibodies directed against donor antigens on endothelial cells. Acute antibodymediated necrotizing acute vasculitis in an interlobular artery with extensive fibrinoid necrosis of the muscularis. The vascular and interstitial infiltrates of mononuclear leukocytes indicate concurrent acute cellular rejection. If necrotizing arteritis develops, fewer than 30% of grafts survive 1 year, even with aggressive immunosuppression. It is characterized by infiltration of the interstitium, tubules, arteries, arterioles or glomeruli by T lymphocytes and macrophages. Nuclei of infiltrating lymphocytes vary in size and shape because the cells are at various stages of activation and include immunoblasts (see Chapter 26). Glomerular infiltration by mononuclear leukocytes with obliteration of capillary lumens causes acute transplant glomerulitis). Renal transplants with tubulitis but not endarteritis have an 80% chance of 1-year graft survival, compared with 60% for allografts with endarteritis. Chronic transplant arteriopathy affects arteries of all sizes, including the main renal artery. Foam cells may be conspicuous, and the internal elastic lamina may be interrupted. Ischemia due to arterial and capillary narrowing may lead to tubular atrophy and interstitial fibrosis. Acute tubulointerstitial cellular rejection with tubulitis indicated by lymphocytes on the epithelial side of the basement membrane (periodic acid­Schiff stain). Acute cellular vascular rejection with endarteritis indicated by mononuclear leukocytes infiltrating the intima of an arcuate artery. The lumen of this mediumsized artery is occluded by a thickened intima, which contains a few inflammatory cells. The frequency and significance of recurrence vary among different types of glomerular disease (Table 22-15). Unfortunately, both drugs are nephrotoxic and can injure both kidney allografts and native kidneys of patients given these drugs for other reasons. The most characteristic renal lesion is an arteriolopathy that begins with smooth muscle cell degeneration and necrosis. In fulminant cases, vascular lesions resemble full-blown thrombotic microangiopathy, with circumferential fibrinoid arteriolar necrosis. In chronic toxicity, there are zones of interstitial fibrosis and tubular atrophy ("striped fibrosis"). Intranuclear viral inclusions in tubular cells may suggest this possibility, and immunochemical staining can confirm the diagnosis. Tumor size, which has been used to separate adenomas from carcinomas, is problematic because all carcinomas start out as small lesions. Renal epithelial neoplasms smaller than 3 cm rarely metastasize, but "rarely" is not "never. Neoplasms smaller than 5 mm with papillary or tubulopapillary growth patterns can be considered adenomas. Papillary renal adenomas occur more often with advancing age and are incidental autopsy findings in 40% of patients older than 70. They are plump, with abundant, finely granular, acidophilic cytoplasm and round nuclei that lack atypia. The distinctive appearance of the tumor is due to abundant mitochondria in the cytoplasm. Oncocytomas are typically mahogany-brown due to mitochondrial lipochrome pigments. Of patients with tuberous sclerosis, 80% have angiomyolipomas, but most patients with angiomyolipomas do not have tuberous sclerosis. These lesions are mixtures of well-differentiated adipose tissue, smooth muscle and thick-walled vessels.

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