Mark Corson

By P. Fedor. Claremont McKenna College.

Air in the bladder without a history of recent catheterization is diag- nostic of a communication with the gastrointestinal tract discount 60caps ashwagandha fast delivery. The goals of sur- gical therapy are to minimize morbidity and mortality ashwagandha 60 caps, remove the septic focus and diseased colon ashwagandha 60caps visa, avoid or at least minimize the risks of a second operation, and convert an emergent situation to an urgent or elective operation. Infectious Colitides Infections of the large bowel usually cause diarrhea and can produce fever or abdominal pain. It is critical to elicit a complete history from the patient, including recent travel, unusual ingestions suspect for food poisoning, similar illnesses among family members, recent hospitalizations, treatment with antibiotics, sexual history, immuno- suppression, and evidence of systemic disease. Diarrhea that develops during antibiotic administration may be related to a change in the bacterial flora of the colon. However, a minority of patients on antibiotics have a proliferation of the toxin-producing strains of Clostridium difficile, a gram-positive, anaerobic organism. Symp- toms can occur both during antibiotic administration and weeks to months after cessation of treatment. The diagnosis is made by rapid immunoassays that test for antigens or toxins in the stool. On endo- scopic exam, the mucosa can look inflamed or develop plaque-like membranes, which is why it has been called “pseudomembranous” colitis. Volvulus Intestinal volvulus is a closed-loop obstruction of the bowel resulting from an axial twist of the intestine upon its mesentery of at least 180 degrees; this results in luminal obstruction and progressive strangula- tion of the blood supply. The early diagnosis and treatment of volvu- lus are important in avoiding intestinal ischemia or gangrene that can lead to a high morbidity and mortality. The more common sigmoid volvulus usually presents with the triad of abdominal pain, distention, and obstipation. On exam, the abdomen is dis- tended dramatically, with high-pitched bowel sounds and tympany to percussion. When patients do not show signs of intestinal strangulation, the initial treatment of choice is endoscopic decompression; this allows the volvulus to reduce so that surgical treatment can be performed elec- tively, after a full mechanical bowel preparation, with lower morbidity and mortality. Rigid sigmoidoscopy can reduce and decompress the bowel, evaluate the rectal and colonic mucosa, and allow for the passage of a rectal tube to keep the bowel decompressed. The goals of treatment are to untwist and decompress the bowel before strangulation and to prevent recurrences. Those patients admitted with signs of sepsis indicative of gangrenous bowel must be resuscitated aggressively and taken emergently to the operating room. Cecal volvulus is the second most common type of volvulus, although it is the cause of only 1% of all intestinal obstructions. Most patients present with symptoms of a small-bowel obstruction: nausea, vomiting, cramping, abdominal pain, and distention. Two types of volvulus can occur: an ileocolic twisting, generally in a clockwise direc- tion; or a cecal bascule, which is an anterior and superior folding of the cecum over the ascending colon. These patients cannot be reduced endoscopically and require oper- ation for definitive treatment. If the bowel is gangrenous, right hemi- colectomy with ileostomy is the standard treatment. However, if no perforation is present and the patient is hemodynamically stable, then an ileocolec- tomy and primary anastomosis may be performed safely. Colon and Rectum 461 Malignant Diseases Incidence Colorectal cancer is the second leading cause of death by cancer in the United States (estimated at 15% of all malignancies). Approximately 30% are located in the rectum, 28% in the sigmoid, 9% in the descend- ing colon, 11% in the transverse colon, 9% in the ascending colon, and 13% in the cecum. Screening and Surveillance Cancer screening refers to the testing of a population of apparently asymptomatic individuals to determine the risk of developing colorec- tal cancer. Various screening and surveillance modalities are available to detect colorectal cancers and adenomatous polyps (Table 25. Sur- veillance refers to the ongoing monitoring of individuals who have an increased risk for the development of a disease. Signs and Symptoms The presentation of large-bowel malignancy generally falls into three categories: insidious onset of chronic symptoms, acute onset of intestinal obstruction, and acute perforation. The most common pre- sentation is that of an insidious onset of chronic symptoms (77–92%), followed by obstruction (6–16%), and perforation with local or diffuse peritonitis (2–7%). Unfortunately, patient and physician alike often attribute the bleeding to hemorrhoids. Change in bowel habits is the second most common complaint, with patients noting either diarrhea or constipation. Eisenstat eralized peritonitis, or, if walled off, it may present with obstruction or fistula to an adjacent structure, such as the bladder. Staging Staging systems are important for predicting outcomes, selecting patients for various therapies, and comparing therapies for like patients across institutions. For a tumor to be considered as an inva- sive cancer and staged, it must penetrate through the muscularis mucosa. Several classification systems are utilized, including the Dukes, which is based on the extent of direct extension, along with the presence or absence of regional lymphatic metastases for the staging of rectal cancer. Dukes’ A lesions are those in which the depth of pene- tration of the primary tumor is confined to the bowel wall. Dukes’ B lesions have primary tumor penetration through the full thickness of the bowel to include serosa or fat. Although not initially described, it became accepted by common practice to add a fourth category for distant spread (D) outside the resected specimen.

The cassette can be looked upon as a very efficient package for resistance genes in that the cassette structure mediates a genetic movability to single resistance genes discount 60caps ashwagandha overnight delivery, a powerful recombination machinery ashwagandha 60 caps without a prescription. The cas- sette has only two functional components; one is the structural resistance gene without a promoter order 60caps ashwagandha otc, the other is a recombination component called 59be (base element). Despite its name, the latter can vary in size between 57 and 141 base pairs and is located downstream of the structural gene. The cassette can exist in two forms: either as a circular nonreplicating molecule, or integrated in the attI site of the integron (Fig. Cassette integration or excision is effected by an integrase, expressed from a gene int also located on the integron. The integrase catalyzes a site-specific recombination, which includes recognition of the 59be of the cassette by the integrase, which by recombination integrates it at the specific attI site located at the upstream end of the int gene. The 59be end of the integrated cassette forms a new specific recombination site, attC, which is recognized by the integrase, particularly at the cutting out of cassettes. The integrase gene int is expressed from right to left, while the resistance genes (in this case, Tp for trimethoprim resistance via drug-resistant dihydrofolate reductase, and Oxa for oxacillin resistance via oxacillin-degrading betalactamase) are expressed from left to right and from the promoter P located in the upstream part of the int gene. Further cassettes can be inserted at the attI site, giving the integron the ability to form an assortment of integron-borne combinations of antibiotic resistance genes. A single integron has been observed to carry eight different antibiotic resistance cassettes. This promoter is responsible for the transcription of the structural genes in all the cassettes situated downstream of the attIsite. The integron is thus a very efficient vehicle for the spread of resis- tance genes. More than five different types of antibiotic resistance–carrying integrons have now been described. They differ among themselves by different amino acid sequences of their integrase enzymes. Hundreds of different integron-borne resistance gene cassettes have been identified. They differ by carrying different resistance genes against many different antibi- otics, and also by differences in the nucleotide sequence of the 59be. The different cassettes do not seem to have a specificity for a particular integrase. They carry a mobile genetic repertoire, the units of which efficiently move from inte- gron to integron and then contribute intensively to the spread of resistance genes. Antibacterial agents, antibiotics, have been distributed in the biosphere for about 70 years. From an evolutionary point of view, this is a very short period of time, and the degree of homology between the five integrases is roughly 40 to 60%, suggesting that their evolutionary divergence extends much longer. A similar structure must have been available in the microbial world for a long time, which later, under the selection pressure of antibiotics, developed into the resistance-spreading genetic vehicle we see today. These short sequences are very similar to 59be, described as a cassette component of the resistance-mediating integrons. One case is a resistance cassette carrying trimethoprim resistance (dfr6), and another is that of a betalactam resistance cassette carrying the gene carb4. It could be surmised to be an old structure evolutionarily, which by being able to exchange genes, has given its host a valuable adapt- ability upon the advent of drastic changes in the environment. In the case of the cholera bacillus, it is known that it survives bound to plankton in the sea, and then appears at times as a pathogen in epidemics. Most of the cassette-borne genes in the superintegrons studied are unknown and have no counterparts in available databases. In the case of the epidemiologically well-known Vibrio cholerae strain El Tor, the superintegron found carries an array of 179 cassettes, occupying about 3% of the total genome. In a similar fashion, the antibiotic resistance integron mediates adaptability and survival following the drastic environ- mental changes that the distribution of antibiotics has created. Speculatively, resistance integrons could have emerged from superintegrons by genetic recombinations under the selection pressure of antibiotics, by the entrapment of integrase genes and their corresponding attI sites by mobile genetic structures such as transposons. Thus by use of plasmid replicons, recombination mechanisms, and gene transfer mechanisms, bacteria can use the enormous pool of antibiotic resistance genes that are accessible when needed. No microbiologist can refrain from marveling at the ability of microbes to resist our best efforts to control or eliminate them. They have inhabited the world and adapted to many hostile environments for almost 4 billion years, so we cannot believe that we can conquer them within some seven decades of remedial effort. Pathogenic bacteria growing in human tis- sues have many different receptors for selective antibiotic action. Medicines that act pharmacologically, on the other hand, inter- fere with unchangeable physiological receptors in the tissue cells of humans and animals. For bacteria the presence of antibiotics involves a dramatic change in the environment, and the great ability of bacteria to adapt to changes in the environment (e. This rate of growth is reflected in very short generation times, which in the test tube can be measured in minutes and in human tissues in hours. Available antibi- otics are in many cases related to each other in terms of mechanisms of action on bacteria and then encounter similar mechanisms of resistance in bacteria. Antibiotics can be seen as appearing in families within which cross resistance is com- mon. In lists of antibacterial agents used for medical purposes in Western industrialized countries, there are ususally about 60 of these agents, antibiotics for systemic use. Roughly 50 of these can be included in five families, within which cross resistance occurs.

Perform a panel on the incompatible unit coating the red cells ashwagandha 60caps overnight delivery, or the patient may have an alloantibody to a low-frequency antigen purchase ashwagandha 60 caps on line. An Blood bank/Apply principles of special procedures/ alloantibody to a high-frequency antigen would Incompatible crossmatch/3 agglutinate all units and screening cells order 60caps ashwagandha mastercard. A The incompatible unit may have red cells coated autocontrol are positive in all phases. Cold and warm alloantibody mixture would cause antibody screen, crossmatch, and Blood bank/Evaluate laboratory data to make patient autocontrol to be positive. Alloantibodies identifications/Incompatible crossmatch/3 would not cause a positive patient autocontrol. What is the first step in a major confirms the antibody identification; antigen typing crossmatch? D The unit may be used in the general blood inventory, be crossmatched if it is properly labeled and only cellular elements C. An eluate Blood bank/Apply principles of special procedures/ would be helpful to remove the antibody, followed Incompatible crossmatch/2 by a cell panel in order to identify it. What corrective action should be taken when blood rouleaux causes positive test results? How long must a recipient sample be kept in the blood bank following compatibility testing? Perform a reverse grouping on donor plasma must be kept for 7 days following compatibility B. All of these options albeit in small amounts, in B-positive and O-positive Blood bank/Apply principles of basic laboratory units. B The abbreviated crossmatch usually consists of a type and screen and an immediate spin crossmatch. When a patient has not been transfused in the past 3 months Blood bank/Apply principles of basic laboratory procedures/Crossmatch/1 4. Check for a clerical error(s) biological characteristics/Transfusion reactions/1 C. B Over 90% of transfusion reactions are due to some Blood bank/Apply knowledge of standard operating type of clerical error. The most time-saving approach procedures/Transfusion reactions/2 would be to check all paperwork before performing any laboratory testing. What is the pathophysiological cause surrounding anaphylactic and anaphylactoid reactions? Antibody in patient serum is detected 3–7 days severe form of allergic transfusion reaction and are after transfusion, and is attached to donor red associated with deficient or absent IgA in the blood cells patients, allowing them the capability to form anti- B. These patients must be transfused with washed combine with allergens in patient plasma cellular products where the plasma has been C. B A transfusion reaction that occurs several days after a pregnancy transfusion of blood products is probably a delayed D. Patient is deficient in IgA and develops IgA immunologic reaction due to an antibody formed antibodies via sensitization from transfusion or against donor antigens. This is a classic example of a pregnancy reaction caused by an antibody such as anti-Jka. A patient has a hemolytic reaction to blood react with patient granulocytes and cause acute transfused 8 days ago. A 68-year-old female diagnosed with neutropenia 1% of all transfusions, results in a temperature and inflammation of the left hand was typed as A rise of 1°C or higher, is associated with blood positive, and received 1 packed red blood cell unit. Delayed hemolytic biological characteristics/Transfusion reactions/2 Blood bank/Correlation of laboratory and clinical 7. Two days later, he developed a Answers to Questions 5–9 fever and appeared jaundiced. Te donor cells were likely positive for the Jkb where the patient was most likely exposed to the antigen b Jk antigen at some point in his life, and upon D. Te recipient cells were likely positive for the Jkb re-exposure to the antigen, the antibody titer rose antigen to detectable levels. Panel on pre- and post-transfusion samples the urinalysis, microscopic red cells were also found. A febrile nonhemolytic reaction is highly consistent with both symptoms and post- transfusion test results. B negative and transfused 1 unit of packed red He had a 20-year history of head trauma and was blood cells, also B negative. During the transfusion, his temperature rose from His blood type was A positive with a previously 36. He was transfused with 205 mL before attributed the reaction to the Fya antigen being a reaction was called by the transfusionist. A prewarm crossmatch was Blood bank/Correlation of laboratory and clinical incompatible in both the pre- and postspecimen. She received 269 mL from the second unit before a reaction was Answers to Questions 10–12 called. Te transfused before a reaction was called are consistent patient expired approximately 12 hours from the with volume overload. What type of reaction not meet criteria for a febrile reaction, and evidence was most likely present? A This case represents an acute hemolytic reaction where the patient had previous sensitization to E and c antigens. This brings to light the importance of running a panel whenever the patient has a positive antibody screen regardless of previous results.