The following factors may have contributed to making the patient seriously ill. First, the patient is elderly and there have to be concerns about his immune response capability as if it is diminished he will be more predisposed to infections. Second, he is already debilitated by his current infection as evidenced by his lethargy and poor appetite and this increases concern about his ability to defend himself against infection. Last, there are concerns about the hospital environment and the presence of antibiotic resistant strains of pathogens found there, and as the infection is a respiratory one it is easy to speculate on how he got it. You should explain to his family how this diverse set of conditions may have conspired to make the patient seriously ill. It is also incumbent upon you to watch the progress of this patient carefully for signs that his condition is not improving.
Question A: The explanation of her condition could be as simple as the development of resistance to antibiotics by the Salmonella organisms that infect her. As she has been treated over and over again, but still comes down with the same infection, it is also necessary to talk to her about how Salmonella has a way of infecting the gallbladder, resulting in the continuous release of pathogens over time, and causing the recurring infections.
Question B: Salmonella has a way of infecting the gallbladder causing the continuous release of pathogens over time. If this is the case, removal of the gallbladder will alleviate this problem.
Question C: The antibiotics were able to rid the body of the accessible Salmonella but those that were harboured in the gallbladder were able to escape this therapy. Therefore they could continue to be the source of subsequent infection.
Question A: The most likely reason is that only four of the students were susceptible and that the 22 children that were not infected had either received the MMR vaccine that prevents measles infection or had previously had the measles and were therefore immune to reinfection.
Question B: It may be that she had not been vaccinated against measles. This may be because migrant workers and their families move around a great deal and therefore their children may not have received the recommended vaccinations.
Question C: These children may not have been vaccinated and there are several possible explanations for this lack of vaccination, including parental wishes. It is also possible that these children were vaccinated but the procedure failed to confer immunity to the children, possibly due to problems with the vaccine used or with the immune system of the children.