By I. Jack. Simpson College, Redding California. 2018.

Instead purchase 500 mg cefuroxime mastercard, the Manual focuses on principles and practices of disease management with specific information on only a sub-set of priority animal diseases of wetlands cefuroxime 250 mg lowest price. Prioritisation of important diseases is not as easy as it sounds as ‘importance’ may depend on personal generic cefuroxime 250mg, cultural or organisational perspectives. Taking an ecosystem approach to health helps ensure that diseases are seen, and dealt with, from a broader perspective with an understanding and appreciation of the interconnectivities. An experts workshop was held in 2010 to perform a disease prioritisation exercise and identify which diseases were of greatest importance, for which specific factsheets would be produced. The aim of the workshop was to identify approximately 30 of these priority animal diseases of wetlands which also impact humans, ensuring that this subset contained at least some diseases of each animal taxa, and for all regions of the world, to help maximise the utility of the Manual. The first task of the workshop drew up a long list of animal diseases associated with wetlands. Each disease’s relevance to wetlands was scored, priority being given to those diseases where either the host, pathogen/toxin or vector was entirely dependent on wetlands. Diseases were then scored according to their impact on: Wildlife health (data were often lacking so expert judgements were made); Livestock health; Human health; and Livelihoods. A number of diseases, such as tick-borne diseases were grouped together as many of the practical approaches to managing them were similar. The scoring was then summed, using a weighting towards relevance to wetlands and impacts on wildlife. This decision was made given the focus of the Manual and the available information already in existence regarding livestock diseases. Ultimately, the factsheets that were produced and presented within this chapter, cover a broad range of priority animal diseases in wetlands, and together cover at least some diseases of all taxa, in various geographical regions. Points for consideration The reader must appreciate that the factsheets presented within this chapter represent information on only a sub-set of diseases and thus must not constraint thinking with respect to trying to diagnose a disease. Animal health expertise should always be sought when making decisions on priority diseases of particular wetlands. It is also worth understanding that many disease problems are multifactorial and a single disease may not be responsible. The causes of lesser flamingo mortality events appear to be multifactorial and not due to one specific disease. The thinking of the wetland manager must not be constrained by the limited number of disease factsheets presented herein (Ruth Cromie). For a wetland manager faced with a disease problem in need of a rapid diagnosis, expert animal disease expertise should be sought from local or national authorities. This section merely provides some guidance to the key questions to help the wetland manager to begin to ‘eliminate’ some disease possibilities and to assist the dialogue with disease professionals conducting an epidemiological investigation. Further relevant concepts regarding epidemiological information are provided in ►Section 3. Many abiotic diseases, such as anthropogenic toxic diseases, may have a broad geographical range. Conversely, most biotic diseases have a defined geographical range determined by the range of the pathogen, host or vector. The nature of trade (legal and illegal) and other anthropogenic movements can allow the introduction of disease into new areas and so this should be borne in mind – novel disease is a possibility. The character of the wetland greatly affects the nature, prevalence and incidence of associated diseases. As an example, deep lakes or fast flowing rivers are much less likely to be sources of schistosomiais or Rift Valley fever as the vectors of these diseases (freshwater snails and mosquitoes, respectively) will be less abundant. A wetland manager should familiarise themselves with the diseases associated with the type of wetland for which they are responsible. The species affected by a particular disease are a key part of an epidemiological investigation and will help guide a wetland manager and animal health professional into considering possibilities of a cause. As an example, within a biodiverse wetland, an outbreak of avian botulism may kill many waterbirds and leave other taxa unaffected, whereas, a harmful algal bloom may affect almost all animal taxa present. A wetland manager should become familiar with how seasons trigger health events within a particular wetland. A wetland manager should be familiar with how diseases are transmitted, which then allows a better ability to assess risk and potential cause of disease. A strong likelihood of water-borne pathogens associated with faecal contamination having entered waterways provides a pointer for a wetland manager to start contemplating the range of associated diseases that might be at play, e. As another example, a relative absence of invertebrate vectors such as mosquitoes may make an outbreak of Rift Valley fever unlikely. A wetland manager should know what represents ‘normal’ behaviour and ecology in livestock and wildlife in the wetlands they manage. Deviations from this normal state, whether behavioural or otherwise, may then provide a good indication of the disease processes at play. Determining the potential impacts of a disease will be impossible without a diagnosis from animal health experts, however, the wetland manager will be able to contribute to the impact assessment given their knowledge of human, livestock and wildlife activities within a wetland site. Wetland characteristic and geographical range: a mesotrophic lake in Iceland and a eutrophic lake in Nepal, choked with invasive alien water cabbage Pistia spp.

Patients require resuscitation and Gastric ulcer: emergency surgery to locate and close the duodenal r H buy cefuroxime 500 mg free shipping. Acute bleeds re- Repeat endoscopy with biopsies is essential in all gastric quire resuscitation to stabilise the patient and may ulcers until completely healed cefuroxime 250mg without prescription, as there may be an un- require urgent endoscopic treatment (see page 147) discount cefuroxime 250mg on-line. If the ulcer does not heal within Early endoscopy can reduce the risk of rebleeding by 6months then surgery should be considered. In patients with rheumatoid arthritis or velopment of outflow obstruction (pyloric stenosis). Fi- broticstenosisrequiressurgicalinterventionfollowing Helicobacter pylori treatment of any electrolyte imbalances resulting from copious vomiting. Older patients Aetiology and those with suspicious features should undergo en- The transmission of H. It produces an enzyme that breaks ing this treatment a further endoscopy is not neces- down the glycoproteins within the mucus. If symptoms persist or recur (or in all patients changes in the secretory patterns within the stomach initially presenting with complications) a urea breath along with toxin-mediated tissue damage. Initial infec- test should be performed at 4 weeks and further erad- tion causes an acute gastritis which rapidly proceeds to ication therapy used if positive. Chapter 4: Disorders of the small bowel 163 Clinical features Aetiology/pathophysiology Most people become colonised by H. The excess acid causesinactivationofduodenal/jejunallipasesandhence Investigations steatorrhoea also occurs. Management Noninvasive tests can be performed if an endoscopy is Resection of the gastrinoma should be attempted but not indicated. High-dose proton pump belled urea, if the bacteria is present the urea is broken inhibitors are also used. Other treatment options in- down releasing labelled carbon dioxide which is de- clude octreotide, interferon α,chemotherapy and hep- tected in the breath. In inoperable tumours 60% of patients survive 5 years r Serological testing is simple, non-invasive and widely and 40% survive 10 years. Disorders of the small bowel Management and appendix First line eradication (triple) therapy consists of a pro- ton pump inhibitor, amoxycillin or metronidazole, and clarithromycin for 1 week. Second line (quadruple) ther- Acute appendicitis apy is with a proton pump inhibitor, bismuth subcitrate, Definition metronidazole and tetracycline. Compliance with treat- Inflammatory disease of the appendix, which may result mentisveryimportantforsuccessfultreatment. Incidence Commonest cause of emergency surgery of childhood Zollinger–Ellinson syndrome (3–4 per 1000). Definition Pathological secretion of gastrin resulting in hypersecre- Age tion of acid. Ultrasound is in- Aetiology/pathophysiology creasingly being used but does not exclude the diagnosis. Accumula- Conservative treatment has little place, except in patients tion of secretions result in distension, mucosal necrosis unfit for surgery. Fluid resuscitation may be required and invasion of the wall by commensal bacteria. Inflam- prior to surgery and intravenous antibiotics are com- mationandimpairmentofbloodsupplyleadtogangrene menced. Once perforation has occurred there is r Under general anaesthetic the abdomen is opened migration of the bacteria into the peritoneum (peritoni- by an incision along the skin crease passing through tis). Theoutcomedependsontheabilityoftheomentum McBurney’s point (one third of the distance from a and surrounding organs to contain the infection. The muscle fibres in each muscle layer Clinical features are then split in the line of their fibres (grid iron in- This is a classic cause of an acute abdomen. The mesoappendix is divided with ligation of tially periumbilical, then migrates to the right iliac fossa. The appendix is ligated at its There is mild to moderate fever, nausea and anorexia. The wound is then ment of the disease may be over hours to days partly closed in layers. In most cases, the appendix is tally particularly if the omentum is wrapped around the removed to avoid confusion if patients ever re-present appendix, or an abscess has formed. Macroscopy Prognosis The appendix appears swollen and the surface vascula- Uncomplicated appendicitis has an overall mortality of ture is yellow. Microscopy Meckel’s diverticulum Initially there is acute inflammation of the mucosa, which undergoes ulceration. As the condition progresses the inflammation An ileal diverticulum occurring as a result of persistence spreads through the wall until it reaches the serosal sur- of part of the vitellointestinal duct. Chapter 4: Disorders of the small bowel 165 Incidence due to ulceration of the adjacent ileum.

Risk factors include previous history of throm- aged to stop smoking at least 6 weeks prior to surgery discount cefuroxime 500mg with amex. Wherever possi- cated unless there are acute respiratory signs or severe ble buy cefuroxime 500 mg otc, risk factors should be identified and modified (in- chronic respiratory disease with no film in the last cluding stopping the combined oral contraceptive pill 12 months discount 250 mg cefuroxime with visa. Preop- coagulant or antiplatelet medication and chronic liver eratively all therapy should be optimised; pre- and disease may cause perioperative bleeding. Postopera- with known coagulation factor or vitamin K deficien- tive analgesia should allow pain free ventilation and cies may require perioperative replacement therapy. Diabetes mellitus Patients with diabetes are at increased risk periopera- Liver disease tively both from the diabetes itself (hypoglycaemia and Patients with chronic liver disease may have im- ketoacidosis) and from the complications of diabetes (is- paired coagulation (vitamin K and coagulation factor chaemic heart disease, vascular insufficiency, renal fail- deficiencies), altered metabolism of drugs, increased ure and increased risk of infection). Coagulation deficiencies should be corrected tervention, but should have perioperative blood glu- prior to surgery and careful fluid balance is essential. The patient’s alcohol intake should be elicited; symp- r Patients on oral hypoglycaemic agents should omit toms of withdrawal from alcohol may occur during a their drugs on the morning of surgery (unless under- hospital admission. In more major surgery, or Pre-existing renal impairment predisposes to the devel- when patients are to remain nil by mouth for a pro- opment of acute tubular necrosis. Hypotension should longed period, intravenous dextrose and variable dose be avoided and urinary output should be monitored so intravenousshortactinginsulinshouldbeconsidered. Close In patients requiring emergency surgery there may not monitoring of blood sugar and urine for ketones is be enough time to identify and correct all coexistent essential. It is however essential to identify any cardiac, should convert back to regular subcutaneous insulin respiratory, metabolic or endocrine disease, which may therapy. Any anaemia, fluid and nutrition may cause significant injury if extravasation electrolyte imbalance or cardiac failure should be cor- occurs. Other complications of parenteral nutrition rected prior to surgery wherever possible. Specific guidelines regarding the use of perioperative an- tibiotic prophylaxis vary between hospitals but these are Postoperative complications generally used if there is a significant risk of surgical site infection. They are indicated in most gastrointesti- Postoperative complications may occur at any time nal surgery, neurosurgery, surgery involving insertion of post-surgery and include general surgical complications aprosthesis (including joint replacement), transurethral (bleeding, infection, deep vein thrombosis), those spe- prostate resection, coronary artery bypass surgery and cific to the procedure (anastomotic leaks, fistulae, adhe- lower limb vascular surgery. Prophylaxis for immunod- sions, wound dehiscence) and complications secondary eficient patients requires expert microbiological advice. It requires aggressive management and may necessitate return Nutritional support in surgical patients to theatre. Reactive haemorrhage occurs from small Significantnutritionaldeficiencyimpairshealing,lowers vessels, which only begin to bleed as the blood pres- resistance to infection and prolongs the recovery period. Blood replacement may be Malnutrition may be present preoperatively particularly required and in severe cases the patient may need to in the elderly and patients with malignancy. Enteral nutrition is the treatment of choice in all pa- r Alow-grade pyrexia is normal in the immediate post- tients with a normal, functioning gastrointestinal tract. Liquid feeds either as a supplement or replacement pletion, renal failure, poor cardiac output or urinary may be taken orally, via a nasogastric tube or via a gas- obstruction. Liquid feeds may be whole protein, oligopep- isation (or flushing of the catheter if already in situ) tide or amino acid based. These also provide glucose, and a clinical assessment of cardiovascular status in- essential fats, electrolytes and minerals. Mixed Early postoperative complications occur in the subse- preparations of amino acid, glucose and lipid are used quent days. Parenteralnutritionishypertonic,irritantandthrom- High-risk patients should receive prophylaxis (see bogenic. Patients may 16 Chapter 1: Principles and practice of medicine and surgery present with painful swelling of the legs, low-grade Surgical site infection pyrexia or with signs and symptoms of a pulmonary embolism. Definition r Confusion due to hypoxia, metabolic disturbance, in- Surgical site infections include superficial site infections fection, drugs, or withdrawal syndromes. Intestinal fistulae may be managed con- including cannulae) and Streptococci or mixed organ- servatively with skin protection, replacement of fluid isms. The organisms responsible for organ or space and electrolytes and parenteral nutrition. If such con- infections are dependent on the site and the nature servative therapy fails the fistula may be closed surgi- of the surgical condition, e. The risk of surgical perioperative atelectasis unless a respiratory infection site infection is dependent on the procedure performed. Prophylaxis and treatment Contaminated wounds such as in emergency treatment involves adequate analgesia, physiotherapy and hu- for bowel perforation carry a very high risk of infection. Respiratoryfailure Patients at particular risk include the elderly, mal- may occur secondary to airway obstruction. Laryn- nourished, immunodeficient and those with diabetes geal spasm/oedema may occur in epiglottitis or fol- mellitus. In Clinical features the absence of obstruction hypoxia may result from Superficial infections appear as a cellulitis (redness, drugs causing respiratory depression, infection, pul- warmth, swelling and tenderness) around the wound monary embolism or exacerbation of pre-existing margin, there may be associated lymphadenopathy.

Expectation bias occurs when the person measuring the outcome knows the clinical features of the case or the results of a diagnostic test and alters their interpretation of the outcome event cefuroxime 500 mg visa. This is less likely when the interven- tion and outcome measures are clearly objective purchase cefuroxime 250mg without a prescription. Ideally blind diagnosis buy cefuroxime 500mg lowest price, treat- ment, and assessment of all the patients going through the study will prevent these biases. Another problem in the outcomes selected occurs when multiple outcomes are lumped together. Many more studies of therapy are comparing two groups for several outcomes at once and these so-called composite outcomes have been discussed in Chapter 11 in greater detail. Commonly used measures of heart therapies might include death, an important outcome, non-fatal myocar- dial infarction, important but less than death and need for revascularization pro- cedure much less important than death. The use of these measures can lead to over-optimistic conclusions regarding the therapy being tested. When combined, multiple or composite outcomes may then show statistical significance. The primary outcome measures were overall number of Survival analysis and studies of prognosis 363 deaths, and of deaths due to stroke, myocardial infarction, or vascular causes. The end result was that there were no decreases in death from stroke or myocardial infarction, but a 20% reduction in deaths in the patients with peripheral arterial disease. If these patient outcomes were considered as separate groups, the differences would not have been statistically significant. Another danger is that some patients may be counted several times because they have several of the outcomes. There are basically three types of data that are used to indicate risk of an out- come. Interval data such as blood pressure is usually considered to be normally distributed and measured on a continuous scale. Nominal data like tumor type or treatment options is categorical and often dichotomous like alive and dead or positive and negative test results. Ordinal data such as tumor stage is also cate- gorical but with some relation between the categories. There are three types of analyses applied to this type of problem: frequency tables, logistic analysis, and survival analysis. Decision theory uses probability distributions to estimate the probability of an outcome. Frequency tables Frequency tables use a chi-square analysis to compare the association of the out- come with risk factors that are nominal or ordinal. For the chi-square analysis, data are usually presented in a table where columns are outcomes, rows are risk factors, and the frequencies appear as table entries. The observed data are com- pared with the data that would be expected if there were no association. The analysis results in a P value which indicates the probability that the observed outcome could have been obtained by chance when it was really no different from the expected value. Logistic analysis This is a more general approach to measuring outcomes than using frequency tables. Logistic regression estimates the probability of an outcome based on one or more risk factors. Results of logistic regression analysis are often reported as the odds ratio, relative risk, or hazard ratio. For one independent variable of interval-type data and relative risk, this method calculates how much of an increase in the risk of the outcome occurs for each incremental increase in the exposure to the risk fac- tor. An example of this would answer the question “how much additional risk of 364 Essential Evidence-Based Medicine stroke will occur for each increase of 10 mm Hg in systolic blood pressure? For multiple variables, is there some combination of risk factors that will bet- ter predict an outcome than one risk factor alone? The identification of significant risk factors can be done using multiple regressions or stepwise regression analyses as we discussed in Chapter 29 on clinical prediction rules. Survival analysis In the real world the ultimate outcome is often not known and could be dead as opposed to “so far, so good” or not dead yet. It would be difficult to justify waiting until all patients in a study die so that survival in two treatment or risk groups can be compared. Besides, another common problem with comparing survival between groups occurs in trying to determine what to do with patients who are doing fine but die of an incident unrelated to their medical problem such as death in a motor-vehicle accident of a patent who had a bypass graft 15 years earlier. This will alter the information used in the analysis of time to occlusion with two different types of bypasses. Finally, how should the study handle the patient who simply moves away and is lost to follow-up? The data con- sist of a time interval and a dichotomous variable indicating status, either failure (dead, graft occluded, etc. In the latter case, the patient may still be alive, have died but not from the disease of interest, or been alive when last seen but could not be located again. Early diagnosis may automatically confer longer survival if the time of diagnosis is the start time.