By L. Bozep. University of the Incarnate Word. 2018.
It is only when the involved gene is that may injure the marrow include x-rays cheap 1mg cardura fast delivery blood pressure chart lower number, atomic radia- transmitted from both parents that the clinical disease tion order cardura 1mg amex blood pressure for 6 year old, radium, and radioactive phosphorus. One drug or white cells, so that the anemia is accompanied by has been found to reduce the frequency of painful crisis leukopenia (lu-ko-PE-ne-ah), a drop in the number of in certain adults. Removal of the toxic agent, followed by blood some hemoglobin of an alternate form (fetal hemoglo- transfusions until the marrow is able to resume its activ- bin) so that the red cells are not as susceptible to sick- ity, may result in recovery. Some Impaired Production of Red Cells or Hemoglo- medications are now available to stimulate bone marrow bin Many factors can interfere with normal red cell pro- production of specific types of blood cells. The average diet usually provides It is characterized by an enormous increase in the num- enough iron to meet the needs of the adult male, but this ber of white cells. Although the cells are high in number, diet often is inadequate to meet the needs of growing they are incompetent and cannot perform their normal children and women of childbearing age. If this wild proliferation of white cells stems ficiency anemia occurs in people with alcoholism, in eld- from cancer of the bone marrow, the condition is called erly people on poor diets, and in infants or others suffer- myelogenous (mi-eh-LOJ-en-us) leukemia. When the ing from intestinal disorders that interfere with the cancer arises in the lymphoid tissue, so that most of the absorption of this water-soluble vitamin. Both inborn fac- ficiency of intrinsic factor, a gastric juice secretion that tors and various environmental agents have been impli- is responsible for vitamin B12 absorption from the in- cated. Treatment consists of x-ray therapy and chemother- apy (drug treatment), but the disease is malignant and Bone Marrow Suppression Bone marrow suppression thus may be fatal. Physical agents THE BLOOD ✦ 275 Box 13-2 Hot Topics Bone Marrow Transplants: Getting the Gift of LifeBone Marrow Transplants: Getting the Gift of Life arge doses of chemotherapy or radiation are sometimes organs. Unfortunately, these of bone marrow transplant is called an autologous transplant therapies also destroy normal stem cells in the marrow, ham- and is not associated with tissue rejection or GVHD. A bone marrow When bone marrow is to be harvested, the donor is given transplant replaces the hematopoietic cells after aggressive general or local anesthesia, a large needle is inserted into the treatment for leukemia. Hemophilia (he-mo-FIL-e-ah) is a rare hereditary This disease occurs in cases of tissue damage due to mas- bleeding disorder, a disease that influenced history by its sive burns, trauma, certain acute infections, cancer, and occurrence in some Russian and Western European royal some disorders of childbirth. All forms of hemophilia are characterized by a platelets and various clotting factors are used up faster deficiency of a specific clotting factor, most commonly than they can be produced, and serious hemorrhaging factor VIII. Many kinds of studies can be done on blood, and some of Von Willebrand disease is another hereditary clotting these have become a standard part of a routine physical disorder. Machines that are able to perform several a plasma component that helps platelets to adhere (stick) tests at the same time have largely replaced manual pro- to damaged tissue and also carries clotting factor VIII. The con- of red cells in whole blood, is determined by spinning a dition, called thrombocytopenia (throm-bo-si-to-PE-ne- blood sample in a high-speed centrifuge for 3 to 5 min- ah), results in hemorrhage in the skin or mucous mem- utes to separate the cellular elements from the plasma branes. For example, 276 ✦ CHAPTER THIRTEEN done using a hemocytometer (he-mo-si-TOM-eh-ter), a ruled slide used to count the cells in a given volume of blood under the microscope. People who live at high altitudes develop polycythemia, as do patients with the disease poly- cythemia (pol-e-si-THE-me-ah) vera, a disorder of the Red cells bone marrow. These counts are normal ranges, like all normal ranges for humans, may necessary for the evaluation of platelet loss (thrombocy- vary depending on the method used and the interpreta- topenia) such as occurs after radiation therapy or cancer tion of the results by an individual laboratory. The normal platelet count ranges from values much below or much above these figures point to 150,000 to 450,000 per L of blood, but counts may fall an abnormality requiring further study. To measure its level, the hemoglobin is released from the red cells, In addition to the above tests, the complete blood count and the color of the blood is compared with a known (CBC) includes the examination of a stained blood slide color scale. Visual counts are sometimes THE BLOOD ✦ 277 Box 13-3 Clinical Perspectives Counting Reticulocytes to Diagnose DiseaseCounting Reticulocytes to Diagnose Disease s erythrocytes mature in the red bone marrow, they go Mature erythrocyte Athrough a series of stages in which they lose their nucleus and most other organelles, maximizing the space available to hold hemoglobin. In one of the last stages of development, small numbers of ribosomes and some rough endoplasmic reticulum remain in the cell and appear as a network, or reticulum, when stained. When erythrocytes are lost or destroyed, as from chronic bleeding or some form of hemolytic anemia, red blood cell pro- duction is “stepped up” to compensate for the loss. Tests for elec- trolytes, such as sodium, potassium, chloride, and bicar- Coagulation Studies bonate, may be performed at the same time along with tests for blood glucose, and nitrogenous waste products, Before surgery and during treatment of certain diseases, such as blood urea nitrogen (BUN), and creatinine (kre- hemophilia for example, it is important to know that co- AT-in-in). Increased levels of cause clotting is a complex process involving many reac- CPK (creatine phosphokinase), LDH (lactic dehydroge- tants, a delay may result from a number of different causes, nase), and other enzymes indicate tissue damage, such as including lack of certain hormonelike substances, calcium damage that may occur in heart disease. The amounts of the various clotting fac- kaline phosphatase (FOS-fah-tase) could indicate a liver tors are evaluated by percentage to aid in the diagnosis and disorder or metastatic cancer involving bone (see Table 3 treatment of bleeding disorders. Additional tests for coagulation include tests for Blood can be tested for amounts of lipids, such as cho- bleeding time, clotting time, capillary strength, and lesterol, triglycerides (fats), and lipoproteins, or for platelet function. For example, the presence of more than the normal amount of glucose (sugar) dissolved in the blood, a con- A special needle is used to obtain a small sample of red dition called hyperglycemia (hi-per-gli-SE-me-ah), is marrow from the sternum, sacrum, or iliac crest in a pro- found most frequently in patients with unregulated dia- cedure called a bone marrow biopsy. Examination of the cells gives valuable procedure is called the glucose tolerance test and is usu- information that can aid in the diagnosis of bone marrow ally given along with another test that determines the disorders, including leukemia and certain kinds of ane- amount of sugar in the urine.
Occasionally purchase cardura 1 mg visa heart attack untreated, per- the activity of the KATP channel generic cardura 2 mg with visa arrhythmia when to see a doctor, depending on the avail- sons who display drug sensitivities to sulfa-containing ability of glucose. The activity of the KATP channels is modulated by In this situation, a nonsulfonylurea insulin secretagogue the direct binding of sulfonylureas to a speciﬁc subunit can be used (if desired), such as repaglinide or nateglin- of the KATP channel called SUR1. Four SUR1 subunits form a complex with Since diabetic patients with renal or hepatic disease four subunits from the Kir 6. A decrease in alcohol tolerance also has been closure of these KATP channels, lowering the threshold observed in some patients taking sulfonylurea com- for glucose-dependent insulin release. Since sulfonylureas are highly bound to plasma rect vasodilator discussed in Chapter 20) also binds to proteins and are extensively metabolized by microso- SUR1 but keeps the KATP channels open, raising the mal enzymes, coadministration of drugs capable of dis- threshold for glucose-stimulated insulin secretion and placing them from their protein binding sites or inhibit- sometimes causing hyperglycemia in patients. Sulfonylureas are readily absorbed from the gastroin- testinal tract following oral administration but undergo varying degrees and rates of metabolism in the liver First-Generation Sulfonylureas and/or kidney; some metabolites possess intrinsic hy- The ﬁrst-generation sulfonylureas are not frequently poglycemic activity. Thus, the biological half-lives of the used in the modern management of diabetes mellitus sulfonylureas vary greatly, and a comparison of the because of their relatively low speciﬁcity of action, de- drug half-life with the observed duration of action does lay in time of onset, occasional long duration of action, not always show a good correlation. They also tend to have their metabolites are excreted either renally or in the more adverse drug interactions than the second-gener- feces. They are occasionally used in pa- tients who have achieved previous adequate control Clinical Uses with these agents. Sulfonylureas are generally effective in individuals with Acetohexamide (Dymelor) is the only sulfonylurea with uricosuric activity, an action that may be of beneﬁt mild to moderate type II diabetes. Similarly, several drugs, a low to intermediate dose is given initially and weeks may be required to eliminate the drug after dis- then gradually increased until the dosage results in nor- continuation of therapy. Once the maximum recommended dosage particularly when taken with alcohol, and can also cause for a particular sulfonylurea is reached, further increas- hyponatremia. The most common adverse effect associated with sul- Tolazamide (Tolinase) is an orally effective hypo- fonylurea administration is hypoglycemia, which may glycemic drug that causes less water retention than do be provoked by inadequate calorie intake (e. Collectively, sulfonylureas also tend to compound that may be useful in patients who are prone cause weight gain, which is undesirable in individuals to hypoglycemia. Like repaglinide, it is approved for both monotherapy and The second-generation sulfonylureas display a higher in combination with metformin. Nateglinide is taken speciﬁcity and afﬁnity for the sulfonylurea receptor three times a day before meals and achieves peak and more predictable pharmacokinetics in terms of plasma levels within an hour. Nateglinide administra- time of onset and duration of action, and they have tion results in plasma insulin levels that peak within 2 fewer side effects. Nateglinide is also exert mild diuretic effects on the kidney and are metabolized by the liver and excreted by the kidney. Glyburide (DiaBeta, Micronase, Glynase), also known as glibenclamide, is approximately 150 times as potent as tolbutamide on a molar basis and twice as potent as Biguanides glipizide (discussed later). Glyburide is completely me- Biguanides are a group of oral hypoglycemic agents tabolized in the liver to two weakly active metabolites that are chemically and pharmacologically distinct from before excretion in the urine. Metformin is the only approved biguanide for the trointestinal tract within an hour of oral administration treatment of patients with NIDDM that are refractory and excreted in the urine and feces. Metformin does not af- from 5 to 9 hours depending on the frequency of multi- fect insulin secretion but requires the presence of in- ple dosing. When used as monotherapy, metformin rarely Though structurally unrelated to sulfonylureas, the causes hypoglycemia. The incapable of stimulating insulin secretion in nutrient- United Kingdom Prospective Diabetes Study demon- starved -cells, but in the presence of glucose, they strated a marked reduction in cardiovascular comor- demonstrate hypoglycemic effects by augmenting the bidities and diabetic complications in metformin- release of insulin. Insulin ing, anorexia, metallic taste, abdominal discomfort, and levels transiently rise postprandially after repaglinide diarrhea) occur in up to 20% of individuals taking met- administration but generally return to baseline by the formin; this can be minimized by starting at a low dose next meal. Like fer any advantage over the sulfonylureas, it may be phenformin, metformin can cause lactic acidosis, but its helpful in patients with a known allergy to sulfa drugs. Metformin is also class, is a phenylalanine derivative that also works by contraindicated in persons with hepatic dysfunction, but binding to a speciﬁc site on the K –ATP–sensitive chan- it appears to be safe for use in the hepatic steatosis that nel on the surface of -cells. Nateglinide binds with a often occurs with fatty inﬁltration of the liver in poorly higher afﬁnity than does repaglinide and has a faster controlled type II diabetics. Glucovance is a combination of metformin and in conjunction with metformin, sulfonylureas, and and glyburide that may be helpful for diabetics who re- insulin. Met- whether this has any clinical signiﬁcance or persists in formin is usually given two to three times a day at meal- the long term. Thiazolidinediones (sometimes termed glitazones) are Consequently, frequent monitoring of liver transami- a novel class of drugs that were initially identiﬁed for nases is recommended for rosiglitazone and pioglita- their insulin-sensitizing properties. They all act to de- zone, and these drugs should be stopped if transami- crease insulin resistance and enhance insulin action in nases rise to more than two to three times the upper target tissues.
In patients who have BWS generic cardura 1 mg without prescription blood pressure 68 over 48, tumor Hemihyperplasia—A condition in which overde- development is not common after age eight 1 mg cardura mastercard heart attack zing mp3. If hemihyperplasia Neonatal—Neonatal refers to the first 28 days after is present, it may be recognized at birth and may become birth. The risk of tumor development increases significantly when hemihyperpla- Nevus flammeus—A flat blood vessel tumor pres- sia is present. While only 13% of affected individuals ent at birth, also known as a “port wine stain. Most patients with BWS remain at or above the 95th percentile for length through adolescence. Uniparental disomy Advanced bone age can be identified on x ray examina- occurs when an individual receives two copies of a chro- tion. Growth rate usually slows down at around age seven mosome, part of a chromosome, or a gene from one par- or eight. After nine years of age, the average weight ent, as opposed to receiving one copy from each parent. Although In this situation, the amount of gene expression can be height, weight, skeletal, and dental maturity may be changed and cause a disease or disorder. Approximately above average for years, growth rate gradually slows 5-10% of patients who have no family history and a nor- down and eventually children reach average height and mal karyotype have a gene change identified near 11p15, normal proportions. This gene region, p57(KIP2), is a Another feature includes unusual linear grooves tumor supressor region, meaning that its presence sup- within the ear lobes and/or a groove or pit on the top of presses tumor development, but that the loss of a nor- the outer ear. Facial characteristics may include promi- mally functioning region could lead to tumor nent eyes (exophthalmos), “stork bite” birth marks development and potentially lead to BWS. The IGF-2 (telangiectatic nevi) of the upper half of the face, and (insulin-like growth factor-2) gene is also in this region. When a gene change in the p57(KIP2) Genetic profile region is found in either of the parents of the affected The genetics of BWS is complex. Approximately child, the chance for a future child to have BWS could be 85% of individuals who have BWS have no family his- as high as 50% with each future pregnancy. Of these ing 70% of individuals who have BWS, no family his- patients, approximately 20% have paternal uniparental tory, and a normal karyotype have no identifiable cause GALE ENCYCLOPEDIA OF GENETIC DISORDERS 147 for BWS. The chance for other family members to be When considering the diagnosis of BWS, several affected in this case is expected to be low. These include, but are not limited to, infant of BWS have a positive family history and a normal kary- a diabetic mother, Simpson-Golabi-Behmel syndrome, otype. Of these families, up to 50% may have an identi- Perlman syndrome, Sotos syndrome, and Costello fiable gene change in the p57 region. If a male carries identifiable gene change in the p57 region has been iden- the gene change, the chance for having an affected child tified, or if a chromosome abnormality is detected by is increased, but specific risks are not yet available. Up to chromosome analysis, then prenatal testing through 50% of individuals with a positive family history and a chorionic villus sampling or amniocentesis is possible. In this situation, the chance for sound examination could help to reassure parents that the the parents to have another affected child is as high as signs and symptoms of BWS are not present (such as 50%. If any of Approximately 1-2% of patients with BWS have a these signs or symptoms are present, and the couple has detectable chromosome abnormality. In patients who had a previously affected child, then it would be very have a translocation or a duplication of 11p15 detected likely that the present pregnancy is affected as well. If chromosome results are normal, BWS is still a possible cause for the ultrasound findings. The reported incidence for BWS is approximately one in 14,000, although this is likely to be an underesti- mate because of undiagnosed cases. BWS is not found Treatment and management more commonly in any particular sex or geographic Early treatment of hypoglycemia is important to region and has been reported in a wide variety of ethnic reduce the risk of central nervous system damage. Treatment for hypoglycemia may include Major signs or symptoms include: macrosomia, steroid therapy, which is usually required for only one to macroglossia, abdominal wall defect, visceromegaly, four months. For very large omphaloceles, a nios, prematurity, neonatal hypoglycemia, advanced multi-stage operation is performed. The treatment and bone age, heart defects, hemangioma, facial nevus flam- management of the omphalocele depends upon the pres- meus, and the characteristic facial features, which ence of other problems and is very specific to each indi- include underdeveloped midface and possible soft-tissue vidual. A cardiac evaluation is recommended prior to sur- gery or if a heart defect is suspected by clinical evalua- Diagnosis tion. Although there is no official Non-malignant kidney abnormalities, including diagnostic criteria for BWS, most would agree that a renal cysts and hydronephrosis, occur in approximately diagnosis requires the presence of three major findings, 25% of patients.
The eggs secrete enzymes that enable them to pass through the wall of the intestine (Schistosoma Oxamniquine mansoni and Schistosoma japonicum) or bladder (Schistosoma haematobium) purchase 2 mg cardura with visa hypertension quality improvement. In addition trusted 1mg cardura hypertension nih, some eggs Oxamniquine (Vansil) is a tetrahydroquinoline that stimulates parasite muscular activity at low concentra- may be carried to the liver or the lung by the circula- tions but causes paralysis at higher concentrations. Penetration of the skin is associated with petechial hemorrhage, some edema, and pruritus that disappears drug may act by esteriﬁcation and binding of DNA, leading to the death of the schistosome by interruption after about 4 days. With the laying of eggs, esterify oxamniquine to produce a reactive metabolite that alkylates parasite DNA. Resistance results from acute symptoms of general malaise, fever, urticaria, ab- dominal pain, and liver tenderness are reported. Diarrhea or dysentery is associated with infestations by Oxamniquine has a restricted range of efﬁcacy, being S. In Oxamniquine is given orally and is readily absorbed the chronic form of the disease, ﬁbrosis and hyperplasia from the intestinal tract. Side effects include CNS toxicity with unsteadiness Praziquantel and occasionally seizures, especially in patients with a The neuromuscular effects of praziquantel (Biltricide) history of seizures. The drug increases calcium permeability Bithionol through parasite-speciﬁc ion channels, so that the Bithionol (Actamer) is a phenolic derivative whose tegmental and muscle cells of the parasite accumulate mode of action is related to uncoupling of parasite- calcium. This action is followed by vacuolization and the speciﬁc fumarate reductase–mediated oxidative phospho- exposure of hitherto masked tegmental antigens, lipid- rylation. It is highly active after oral administration, with serum concentrations be- against the adult worm but exerts no action against the ing maximal in 1 to 3 hours; the drug has a half-life of migratory stages. Side effects are generally mild and transient; they Dexamethasone decreases plasma praziquantel levels include nausea, vomiting, diarrhea, headache, dizziness, by 50%. It is the most effec- Metrifonate tive of the drugs used in the treatment of schistosomia- sis, possessing activity against male and female adults Metrifonate is an organophosphorous compound that and immature stages. In addition, it has activity cholinesterase and potentiates inhibitory cholinergic ef- against other ﬂukes, such as C. It is contraindicated in preg- of clonorchiasis and paragonimiasis and is an effective nancy, previous insecticide exposure, or with depolariz- alternative agent to niclosamide in the treatment of ing neuromuscular blockers. Initially he (B) Praziquantel thought he was recovering from stomach ﬂu; his ex- (C) Albendazole amination is signiﬁcant for conjunctival hemor- (D) Surgery rhage, bilateral periorbital edema, and severe ten- (E) Thiabendazole derness of neck muscles and jaws. Which of the following as- the West Coast is admitted with abdominal pain, pects of trichinosis are particularly important? Diphyllobothriasis is diagnosed after stool studies are (C) Suramin is used in its treatment with consider- done. While serving with Doctors Without Borders in (E) Piperazine Malaysia, you are seeing a patient who has intermit- tent cough, shortness of breath, and wheezing. Trichinosis should be suspected in a patient who ﬁlaria in the blood, and a chest radiograph showing has any of the cardinal features of periorbital scattered reticulonodular inﬁltrates. Infection is following points is the most important if your diag- acquired after consumption of inadequately cooked nosis is tropical pulmonary eosinophilia (TPE)? Muscle biopsy from (B) Absence of microﬁlariae in blood makes the a tender, swollen muscle (preferably deltoid or gas- diagnosis unlikely. TPE is caused by microﬁlariae in the lungs and examination produced normal ﬁndings except for hyperimmune responsiveness to bancroftian or nonspeciﬁc abdominal discomfort with a complete malayan ﬁlariasis. Paroxysmal respiratory symptoms blood count showing anemia and 22% eosinophils may ﬂuctuate in severity. A stool specimen revealed the character- ways present, is usually very high, and the absence istic eggs of A. No prior history of fever, chills, trauma, or Piperazine or pyrantel pamoate may be used for the headaches was reported on admission. Mebendazole is an effective tomography reveals three ring-enhancing cystic le- drug to be taken for 3 days. Thiabendazole is not sions in the brain parenchyma, and a diagnosis of used in this condition but is used commonly in neurocysticercosis is made. Albendazole at a single dose of management of this condition should include 400 mg is the preferred mode of therapy. It is a 628 VI CHEMOTHERAPY convenient agent for mass treatment programs that with vitamin injections in addition to speciﬁc drug target school children in endemic areas.
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