By L. Emet. Colby-Sawyer College. 2019.
The adoption of (national and international) protocols intended to protect the welfare of donors may be only a first step in ensuring that proper ethical appraisal takes place in any particular case discount atorlip-5 5mg free shipping. This is not just because implementation may be an issue; it is also because formal safeguards can only ever be part of the picture purchase atorlip-5 line. Difficulties in ensuring appropriate ethical appraisal on the ground may particularly arise where health and after-care provision in general is uncertain purchase generic atorlip-5 on-line. However discount atorlip-5 5mg without a prescription, it is just as important (though sometimes politically more delicate) to acknowledge the possibility of addressing scarcity through managing demand. It is striking that public attitudes to markets in health care appear to differ significantly, depending on the care under consideration. Fertility treatment appears to be regarded by many in a light that allows it to leave the nationally- funded health service without too much public complaint. Indeed it is interesting that to some extent the growth of cross-border reproductive care has proved less controversial than attempts by specialists in the field of fertility treatment to drive down demand by educating women 513 regarding their fertility, and encouraging attempts to become pregnant earlier. And there are harder elements of policy, which might conceivably deny material to those who are thought to be particularly reckless with their health. Here the Council pointed out that public health schemes, if they are to be effective, cannot be based on individual consent, because by definition they affect large sections of society. Moreover, in its report, the Council took seriously the view that it is the role of states to limit health inequalities. A stewardship model, then, will aim to provide environments conducive to health, in ways that reflect collectively-endorsed commitments to reasonably healthy lifestyles. It will also seek to reduce the bases of socially inequitable need for bodily material, by reducing the socio-economic contributors to health inequality. In order to ensure that all groups and individuals have a fair opportunity to lead a healthy life, the report further requires that governments work to remove inequalities that affect disadvantaged groups or individuals. The public health report clearly states that public health programmes should not be coercive in their approach, and that measures should largely be implemented after consultation. It also advises that the goal of improving the publics health should be balanced against a commitment to secure and protect important aspects of private or personal life such as privacy. However, it would be consistent with the principles set out in the public health report to give states a responsibility to advise and assist citizens in avoiding practices injurious to their health and encourage and facilitate practices which will benefit them particularly where the means of addressing resultant health problems are in short supply. In the current context it would be particularly relevant to consider the approach the report takes to the issue of obesity which is pertinent to both the causes of disease resulting in organ failure, and the success of subsequent transplants. There is also the possibility of genetic components to disease, where some populations may simply be more susceptible to particular conditions than others, thereby limiting the effectiveness of demand-focused interventions. Therefore, to ensure that no population is disadvantaged by a solution to scarcity that seeks to manage demand, as opposed to increase supply, any solutions adopted must be evidence-based and culturally sensitive. Others felt that recognising any rights of ownership in the body involved an unjustifiable form of objectification or even commodification of the body, arguing that it is persons who exist as embodied beings, and persons should not be treated as commodities. There is also the long-standing legal principle that others may acquire property rights in body parts once separate from the body, if, as a result of the application of skill they have changed the attributes of the material. Our concern here is to highlight the pitfalls that arise when attempting to characterise the relationship between persons and their own bodily material by means of a blanket conception of property. On the contrary, the concept of ownership often rather seems to serve as a metaphor for autonomy and bodily self-determination, principles which can as well imply a rejection of commercialization. Conceptions of the human body and their implications for public attitudes towards organ donation and organ sale Philosophy, Ethics, and Humanities in Medicine 4: 4. Distinct ethical justifications may underpin each of these different alleged entitlements. We then move on to examine these assumptions critically, and to construct our own ethical framework. The rationale offered (often by regulators) is that donation must be founded on altruistic decisions. On property from personhood, symbolic existence and motivation to donate organs Transplantation 193: 200. A useful distinction for our purposes is between behavioural and motivational definitions of the term. Motivational conceptions of altruism define altruistic action in terms of the internal psychological states that produce behaviours. An altruistic action, on this view, is something done because the person concerned wishes to contribute to the welfare of another. Behavioural definitions of altruism, by contrast, focus solely on the costs and benefits of action to the person concerned, without reference to the internal motivational state that may have produced the action in question. A hypothetical example may help to illustrate the difference between the two definitions. Suppose someone gives all their money to charity in the false hope that it will bring fame and increased social status. This action is not motivationally altruistic, but the fact that it may benefit others at great cost to the individual concerned means that it will be regarded as behaviourally altruistic. Many advocates of altruistic donation see altruism as an important virtue, hence as resting on an underlying set of moral and psychological dispositions. We return later in this chapter to a discussion of the potential social value of the promotion of altruism as a virtue (see paragraph 5. It is important to stress that if altruistic donation appears insufficient to meet demand in some areas, we face a choice of whether or not to move to an incentivised system: it is not a necessary step, and we have not assumed in our deliberations that the choice made must be the same across all domains of donation. First, someone may donate biological materials because it also makes them feel good to help others. But cases such as these remain altruistic for our purposes, on the grounds that concern for the welfare of others is a genuine motivator, and on the grounds that a disposition to help others can be reckoned as virtuous whether or not founded on the pleasure such action brings to the donor. Second, someone may wish to help others, but they may also be concerned about how much of their own time they can afford to sacrifice. In these sorts of situations, reimbursement for loss of time, or loss of earnings, can facilitate altruism rather than eliminate it. Third, many real-life cases will feature mixed motivations: someone who is paid well for charitable work may undertake this work for a combination of reasons, including a genuine desire to assist others and a desire to improve their own quality of life. Their altruism remains genuine here, for it might explain why they choose charity work as a career rather than some other (potentially better paid) job. So, we can imagine a person whose desire to donate a kidney is genuinely motivated by concern for the welfare of a stranger. The same is the case for a range of initiatives that reduce barriers to donate for those already inclined to help others, such as workplace blood donation schemes. First, initiatives that reduce barriers to donate can change the decision someone is likely to make, because they change the balance of costs and benefits associated with donation. But the mere fact that these initiatives alter peoples decisions does not mean that they are manipulative. We suggest that initiatives of this sort are unobjectionable, in that they simply remove barriers to an action the individual is already inclined to take. Second, it is useful to distinguish two types of intervention, both of which aim at increasing donation by changing its costs and benefits. Altruist-focused interventions may also offer some form of token reward or thank you, that might prompt the person into action but would not on its own provide a reason for acting if altruistic motivation were lacking. Inevitably, in some cases, the line between these two forms of intervention will be blurred, and in such cases particular care is required. This is true whether the reward involved in egg sharing is viewed either in terms of reduced-price fertility treatment, or as an opportunity to access fertility treatment that would otherwise not be available. Many egg sharers undoubtedly care for the welfare of couples to whom they have donated, and may regard pregnancies enabled by their donation very 523 positively. We accept that non-altruist-focused interventions will sometimes make altruists even keener to act on their altruistic motivation. But such interventions also give individuals who are not concerned with the welfare of others a motivation to donate. We emphasise here, that in our view, donation unaccompanied by altruistic intent is not necessarily unethical in itself: this will depend on all the circumstances surrounding the donation (a point we discuss in greater detail later: see paragraph 6. However, we believe that the distinction between those donating with altruistic intent and those donating primarily for other reasons is a valuable one, both in analysing the current regulatory approaches, and in developing our own ethical framework. This commitment is expressed in a number of international codes and resolutions on donation, by the regulators with whom we met, and by many of the respondents to our consultation. Understood in this light, an incentive could be classed either as an altruist-focused intervention (if the reward is sufficiently small that it would not act on its own to change a persons behaviour) or as a non-altruist-focused intervention (where the reward is calibrated with the aim of providing a reason for action on its own).
Food allergy prevalence in the general population order 5mg atorlip-5 with mastercard, as reported by Buckley buy atorlip-5 now, is estimated to be 0 atorlip-5 5 mg generic. Prevalence purchase atorlip-5 without a prescription, however, appears to be much higher in children with moderate-severe, refractory atopic dermatitis. One study reported that one third of the 63 such patients recruited had immunoglobulin E (IgE)-mediated food allergy ( 7). Studies like those mentioned above have not been systematically conducted in adults, but some surveys suggest the prevalence of food allergy in adults to be 1% to 2%. They are notable for their immediate onset most within 1 hour but frequently within minutes. As with other IgE-mediated reactions they can have a late-phase response 4 to 6 hours later. Protracted anaphylaxis, relatively resistant to epinephrine, has been noted and also has been described with venom anaphylaxis (9). Recent studies have reported foods to be the number one cause of anaphylaxis ( 10,11). Historically, the incidence of fatal and near-fatal food-induced anaphylaxis has been difficult to ascertain, primarily due to a lack of coding in the International Classification of Disease. The four factors that appeared to contribute to a fatal outcome were a concomitant diagnosis of asthma, a delay in the administration of epinephrine, previous allergic reactions to the responsible food, and not recognizing food allergen in the meal. Its function is to digest food into forms more easily absorbed and available for energy and cell growth. In this process it must provide a defensive barrier against any pathogens entering by this route and simultaneously tolerate the many foreign proteins in foods to which it is exposed. Nonimmunologic or mechanical barriers include gastric acid secretions and proteolytic enzymes. These digest proteins into molecules that are less antigenic, either by reducing the size (14) or by altering the structure ( 4,14), as described below in the section on tolerance. Other physical barriers include peristalsis, mucus production, and mucus secretion. The gut epithelium itself provides a barrier against significant macromolecular absorption (15). Physical factors that increase the rate of absorption are alcohol ingestion and decreased gastric acid secretion. Increased acid production and food ingestion both decrease the rate of absorption ( 16). Dimeric secretory IgA accounts for most of the increase in IgA production and serves to bind proteins, forming complexes and thereby decreasing the rate of absorption ( 21). For the macromolecules that do get absorbed as intact antigens approximately 2% ( 19) there is the development of oral tolerance. Tolerance is an immunologic unresponsiveness to a specific antigen, in this case food proteins ( 23). Both the local and systemic immune system appear to play a significant role in the development of oral tolerance ( 22), although the exact mechanisms are not well understood. The processing of antigens by the gut into a nonallergenic or tolerogenic form is important ( 24). This has been reported in studies of mice fed ovalbumin, which is immunogenic when administered parenterally. Within 1 hour after ingestion, a form similar in molecular weight to native ovalbumin was recovered from the serum. This tolerogenic form of ovalbumin induced suppression of cell-mediated responses but not antibody responses to native ovalbumin in recipient mice ( 24). This intestinally processed ovalbumin is distinct from systemic antigen processing ( 24). Mice that were first irradiated were unable to process the ovalbumin into a tolerogenic form. Food hypersensitivity is the result of a loss of or lack of tolerance, the cause of which is likely multifactorial. Until recently some of this immaturity was thought to lead to increased absorption of macromolecules from the gut of infants, but studies now indicate that this is not likely ( 30,31). The importance of local IgA is further supported by the finding of an increase in incidence of food allergy associated with IgA deficiency ( 36). Mast cells that play a significant role in the food allergy reaction also appear to play a role in the maturation of the gut associated with weaning (40), a process affected by the mucosal immune system. This is evidenced by inhibition of small intestinal maturation and decreased numbers of intraepithelial lymphocytes with the addition of cyclosporine A ( 41). It has been noted that there is an increase in systemic antibody production, generally food-specific IgM, and IgG in patients with inflammatory bowel disease and celiac disease ( 36). However, the significance of these antibodies is not known because the patients often tolerate these foods well ( 42,43). Food-specific antibodies are also found in normal individuals, although usually of lower level ( 42). Any disruption of the immunologic or nonimmunologic barriers could alter the handling of antigen and lead to an increased production of systemic antibodies. In individuals with genetic predisposition to atopy, this could lead to IgE production and resultant food hypersensitivity reactions on reexposure ( 45). Many more human studies need to be performed in order to elucidate the mechanisms. The glycoprotein in food is the component that is most implicated in food allergies. Glycoproteins that are allergenic have molecular weights of 10,000 to 67,000 daltons. They are water soluble, predominantly heat stable, and resistant to acid and proteolytic digestion ( 46). Although many foods are potentially antigenic, the vast majority of food allergies involve only a few foods ( 47). The combined results of double-blind placebo-controlled food challenges performed in the United States (primarily in children) showed that eight foods were responsible for 93% of reactions (39). The prevalence of specific allergens may vary for different countries, depending on exposure patterns. Allergens found commonly in children but not in adults (eggs, soy, milk and wheat) are usually outgrown with strict elimination for 1 or more years (48), although evidence of IgE antibodies may persist ( 49). Those with histories of severe reactions may take longer to develop clinical tolerance, up to several years (48,50). The others [peanuts ( 51), tree nuts, crustacea (52), and fish (53)] tend to be lifelong and thus are common to both populations. Some whey proteins found in milk are denatured by heating and routine processing, whereas others are rendered more allergenic (54). Fish allergens may be changed with the canning process, and a patient who cannot tolerate fresh fish may tolerate canned tuna and other processed fish (55). Beef has been reported to have heat-labile allergens; therefore, cooking may abrogate sensitivity ( 56). Peanut allergen is remarkably resistant to any kind of processing, retaining its allergenicity ( 57). Peanut oil has been tolerated by 10 peanut-allergic individuals ( 58), but there have not been adequate studies ensuring its safety. Crustacea also show considerable cross-reactivity ( 65) but the clinical significance remains unknown due to a lack of controlled food challenges. These result in smooth muscle contraction, vasodilation, microvascular leakage, and mucus secretion. Cytokines are also generated over several hours and thought to play a significant role in the late-phase response. Eosinophils, monocytes, and lymphocytes are recruited to the area affected in the late-phase response and release a variety of cytokines and inflammatory mediators. Clinical manifestations of IgE-mediated food allergy depend on the organ systems involved. Reactions can be isolated, in combination, or as part of a generalized anaphylactic reaction. Cutaneous Manifestations Cutaneous manifestations are the most common reaction, but the absence of skin symptoms does not exclude food-induced anaphylaxis ( 12). These cutaneous reactions range from acute urticaria or angioedema to a morbilliform pruritic dermatitis.
Prospective study of extractable latex allergen contents of disposable medical gloves purchase atorlip-5 5mg online. Natural rubber latex allergy in children who had not undergone surgery and children who had undergone multiple operations cheap atorlip-5 5 mg otc. Diagnosis of natural rubber latex allergy: multicenter latex skin testing efficacy study order atorlip-5 5 mg fast delivery. Natural rubber latex skin testing reagents: safety and diagnostic accuracy of nonammoniated latex purchase atorlip-5 paypal, ammoniated latex, and latex rubber glove extracts. A blinded, multi-center evaluation of two commercial in vitro tests for latex-specific IgE antibodies. Routine testing for latex allergy in patients with spina bifida is not recommended. Isolation and characterization of major banana allergens: identification as fruit class I chitinases. A two-dimensional electrophoretic analysis of latex particles reacting with IgE and IgG antibodies from patients with latex allergy. Characterization and identification of latex allergens by two-dimensional electrophoresis and protein microsequencing. Latex allergy: frequent occurrence of IgE antibodies to a cluster of 11 latex proteins in patients with spina bifida and histories of anaphylaxis. Characterization of latex antigens and allergens in surgical gloves and natural rubber by immunoelectrophoretic methods. Comparison of latex antigens from surgical gloves, ammoniated and nonammoniated latex: effect of ammonia treatment on natural rubber latex proteins. Characterization of a major latex allergen associated with hypersensitivity in spina bifida patients. Surgical glove latex glove allergy: characterization of rubber protein allergens by immunoblotting. Rubber elongation factor from Hevea brasiliensis: identification, characterization, and role in rubber biosynthesis. Amino acid sequence of rubber elongation factor protein associated with rubber particles in Hevea latex. Hevein, a lectin-like protein from Hevea brasiliensis (rubber tree) is involved in the coagulation of latex. Purification and characterization of an inhibitor of rubber biosynthesis from C-serum of Hevea brasiliensis latex. Demonstration of beta-1,3-glucanase activities in lutoids of Hevea brasiliensis latex. Class I endochitinase containing a hevein domain is the causative allergen in latex-associated avocado allergy. Crystal structures of hevamine, a plant defense protein with chitinase and lysozyme activity, and its complex with an inhibitor. Hevamine, a chitinase from the rubber tree Hevea brasiliensis, cleaves peptidoglycan between the C-1 of N-acetylglucosamine and C-4 of N-acetylmuramic acid and therefore is not a lysozyme. Identification, cloning, and sequence of a major allergen (Hev b 5) from natural rubber latex ( Hevea brasiliensis). A novel acidic allergen, Hev b 5, in latex: purification, cloning and characterization. Identification of profilin as an IgE-binding component in latex from Hevea brasiliensis: clinical implications. The rubber elongation factor of rubber trees ( Hevea brasiliensis) is the major allergen in latex. Molecular cloning and nucleotide sequencing of the rubber elongation factor gene from Hevea brasiliensis. On the allergenicity of Hev b 1 among health care workers and patients with spina bifida allergic to natural rubber latex. Detection of immunoglobulin antibodies in the sera of patients using purified latex allergens. Latex B-serum beta-1,3-glucanase (Hev b 2) and a component of the microhelix (Hev b 4) are major latex allergens. Purification and partial amino acid sequencing of a 27-kD natural rubber allergen recognized by latex-allergic children with spina bifida. IgE reactivity to 14-kD and 27-kD natural rubber proteins in latex-allergic children with spina bifida and other congential anomalies. Cloning, expression, and characterization of recombinant Hev b 3, a Hevea brasiliensis protein associated with latex allergy in patients with spina bifida. Purified and recombinant latex proteins stimulate peripheral blood lymphocytes of latex allergic patients. The main IgE binding epitopes of a major latex allergens, prohevein is present in its 43 amino acid fragment hevein. IgE from latex-allergic patients binds to cloned and expressed b cell epitopes of prohevein. Allergy to latex avocado, pear, and banana: evidence for a 30 kd antigen in immunoblotting. Crossreactivity between allergens in natural rubber latex and banana studied by immunoblot inhibition. Identification and characterization of avocado chitinase with cross-reactivity to a latex protein. Mutual boosting effects of sensitization with timothy grass pollen and latex glove extract on IgE antibody responses in a mouse model. Basophil histamine release and lymphocyte proliferation tests in latex contact urticaria. Lymphocyte proliferation response to extracts from different latex materials and to the purified latex allergen Hev b 1 (rubber elongation factor). Characterization of T cell responses to Hev b 3, an allergen associated with latex allergy in spina bifida patients. Allergenic and antigenic determinants of latex allergen Hev b 1: peptide mapping of epitopes recognized by human, murine and rabbit antibodies. Murine B-cell and T-cell epitopes of the allergen Hev b 5 from natural rubber latex. Immunological and structural similarities among allergens: prerequisite for a specific and component-based therapy of allergy. A medical-center-wide multi disciplinary approach to the problem of natural rubber latex allergy. Latex gloves with a lower protein content reduce bronchial reactions in subjects with occupational asthma caused by latex. Impact of personal avoidance practices on health care workers sensitized to natural rubber latex. Dyspnea may not be recognized by some patients with asthma, and these poor perceivers may experience acute severe asthma episodes that may be fatal (1). More commonly, patients tolerate or acclimate to decreases in expiratory flow rates. Obtaining spirometry on the initial assessment of a patient with asthma or possible asthma was recommended by the Expert Panel Report 2 of the National Asthma Education and Prevention Program of the National Institutes of Health ( 2). Subsequent measurements are obtained after treatment to demonstrate expected improvement and then at least every 1 to 2 years ( 2). It is often necessary to obtain spirometric values more frequently, depending on the clinical response and severity of asthma. Spirometric results should be considered in terms of accepted parameters and test performance. In addition, a poor seal around the mouthpiece will result in decreased results from air leakage into the environment. Cigarette smokers lose about 45 mL/year, with some more susceptible patients losing as much as 60 mL/year ( 6). Also, a person may be disabled from asthma if there are episodes of severe attacks in spite of prescribed treatment, occurring at least once every 2 months or on an average of at least 6 times a year, and prolonged expiration with wheezing or rhonchi on physical examination between attacks (11). The difference was associated with eosinophil presence in bronchial biopsy specimens but was not explained by differences in neutrophils ( 12). Pulmonary function tests in a 19-year-old man with acute severe asthma The patterns of the expiratory curve and inspiratory loop should be examined. Obstruction on expiration produces a scooping-out pattern or one that is concave upward in appearance (Fig.
Osmotic laxatives or large vol- tion but caused decreased motility and thus a drainage umes of electrolyte solutions are then taken to clear the procedure is required: bowel 12 hours before the procedure (essentially causing r Pyloroplasty in which a longitudinal cut is made in watery atorlip-5 5mg low cost, frequent diarrhoea) buy discount atorlip-5. In 20% of cases buy atorlip-5 5 mg cheap, due is linked to the stomach (the normal pyloric passage to insufcient preparation or patient intolerance purchase atorlip-5 with amex, it is remains intact). Iron and folate are absorbed from the upper small Partial gastrectomy is usual (total gastrectomy is un- bowel. Complications following surgery: r Large bowel surgery Duodeno-gastric reux, may lead to chronic gastritis. Resection of the large bowel often requires temporary or r Recurrenceoftheoriginaldisease(gastriculcer,gastric permanent stoma to allow healing of the relatively frag- carcinoma). Patients require counselling wherever possible r Nutritionalconsequencesincludeweightloss,ironde- prior to surgery. These are subdivided into two categories: r The dumping syndrome is due to the uncontrolled 1 Colostomy (exteriorisation of the colon), which is rapid emptying of hyperosmolar solution into the ush to the skin. Both ends may be exteriorised as small bowel characterised by a feeling of epigastric acolostomy and a mucous stula or the rectal stump fullness after food associated with ushing, sweating can be closed off and left within the pelvis (Hartman s 15 30 minutes after eating. Surgical re- 2 Ileostomy, which requires the creation of a cuff of vision may be indicated. Prior to emergency surgery ag- gastrectomy after a latent period of 20 years possibly gressive resuscitation is required. Resection of tumours, due to bacterial overgrowth with the generation of when of curative intent, involves removal of an adequate carcinogenic nitrosamines from nitrates in food. Complications of intestinal surgery include wound Small bowel surgery infection (see page 16) and anastomotic failure, the Smallbowelresectionisnormallyfollowedbyimmediate treatment for which is surgical drainage and exteriori- end-to-end anastomosis as the small bowel has a plen- sation. Small to medium resections have little functional consequence as there is a relative func- Gastrointestinal infections tional reserve; however, massive resections may result in malabsorption. Denition r Nutritional consequences are severe when more than Bacterial food poisoning is common and can be caused 75% of the bowel is resected. Ingested Investigations spores (which are resistant to boiling) may cause diar- Microscopy and culture of stool is used to identify cause. Recovery All forms of bacterial food poisoning are notiable to occurs within a few hours. The onset oftheclinicaldiseaseoccurs2 6hoursafterconsump- Management tion of the toxins. Canned food, processed meats, milk In most cases the important factor is uid rehydration and cheese are the main source. Antibioticsare istic feature is persistent vomiting, sometimes with a not used in simple food poisoning unless there is ev- mild fever. There is a large animal reservoir (cattle, sheep, Bacilliary dysentery rodents, poultry and wild birds). Patients present with fever, headache and malaise, followed by diarrhoea, Denition sometimes with blood and abdominal pain. Recovery Bacilliary dysentery is a diarrhoeal illness caused by occurs within 3 5 days. It has an in- There are four species of Shigella known to cause diar- cubation period of 12 24 hours and recovery occurs rhoeal illness: within 2 3 days. There are more than 2000 species on the basis of r Shigella exneri and Shigella boydii (travellers) cause antigens, which can help in tracing an outbreak. Salmonella enteritidis (one common serotype is called r Shigella dysenteriae is the most serious. The main reservoir of infection is poul- try, though person to person infection may occur. Di- Pathophysiology arrhoea results from invasion by the bacteria result- Shigella is a human pathogen without an animal reser- ing in inammation. Acutewaterydiarrhoeawithsystemicsymptomsoffever, malaise and abdominal pain develops into bloody di- Clinical features arrhoea. Other features include nausea, vomiting and As outlined above the cardinal features of food poison- headaches. Complications include colonic perforation, ing are diarrhoea, vomiting and abdominal pain. Severe cases may be treated mon in the developing world but also found in with trimethoprim or ciprooxacin. Outbreaks may oc- the United Kingdom, especially in immunocom- cur and require notication and source isolation. It has been suggested from retrospective studies Aetiology/pathophysiology that treatment of E. The tox- Pseudomembranous colitis ins are coded for on plasmids and can therefore be Denition transferred between bacteria. The heat labile toxin Pseudomembranous colitis is a form of acute bowel in- resembles cholera toxin and acts in a similar way. Infections are associated with contaminated food, particularly hamburgers, Investigations only a small bacterial load is required to cause dis- r At sigmoidoscopy the mucosa is erythematous, ulcer- ease. Management The broad-spectrum antibiotics should be stopped and acombination of adequate uid replacement and oral Prevalence metronidazole is used. Geography Giardiasis Occurs worldwide but most common in the tropics and subtropics. Denition Infection of the gastrointestinal tract by Giardia lamblia a agellate protozoa. Aetiology The condition is caused by Entamoeba histolytica,trans- Aetiology mission occurs through food and drink contamination Giardia is found worldwide especially in the tropics and or by anal sexual activity. Pathophysiology The amoeba can exist as two forms; a cyst and a tropho- Pathophysiology zoite, only the cysts survive outside the body. Following The organism is excreted in the faeces of infected pa- ingestion the trophozoites emerge in the small intestine tients as cysts. These are ingested, usually in contami- and then pass to the colon where they may invade the nated drinking water. Clinical features r Patients may have a gradual onset of mild intermittent Patients may be asymptomatic carriers or may present diarrhoea and abdominal discomfort. Subsequently 1 2 weeks after ingestion of cysts with diarrhoea, nausea, bloody diarrhoea with mucus and systemic upset may anorexia, abdominal discomfort and distension. A may be steatorrhoea, and if the condition is prolonged fulminating colitis with a low-grade fever and dehy- there may be weight loss. Complications r Aspirates from the duodenum or jejunal biopsy can r Severe haemorrhage may result from erosion into a be used for identication. A 3-day course of metronidazole or a single oral dose of r Progression of fulminant colitis to toxic dilatation tinidazole are highly effective treatments for giardiasis. Prevention is by improved sanitation and precautions r Chronic infection causes brosis and stricture forma- with drinking water. Management Management Metronidazole is the drug of choice, large liver abscesses r Ciprooxacin, chloramphenicol and amoxycillin have require ultrasound guided percutaneous drainage. Enteric fever (typhoid and r Avaccine is available which gives some protection for paratyphoid) up to 3 years. Denition Typhoid (Salmonella typhi) and paratyphoid (Salmon- Botulism ella paratyphi A, B or C)produce a clinically identical disease. Denition Botulism is a serious food poisoning caused by the Gram Aetiology/pathophysiology positive bacillus Clostridium botulinum. Organisms pass The bacteria are soil borne, spores are heat resistant to via the ileum and the lymphatic system to the systemic 100C. Some secrete salmonella for over a 1 Food borne botulism in which toxin in the food is year and measurement of Vi agglutinin is used to detect ingested. Clinical features 3 Wound botulism in which the organism is implanted 1 The condition typically runs a course of around 1 into a wound. There is gradual onset of a viral like illness with headache Pathophysiology and fever worsening over 3 4 days. There is initially Toxins are transported via the blood stream to the pe- constipation. Botulinum toxin acts to block 2 Week 2 the patient appears toxic with dehydration, neurotransmission. Patients develop an erythematous maculopapular-blanching Clinical features rash with splenomegaly. The illness starts with nausea and vomiting 12 72 hours 3 During week 3 complications include pneumonia, afteringestingtheorganism.