Wanda was doing the laundry thinking about Thanksgiving and the past year. She w
ID: 258112 • Letter: W
Question
Wanda was doing the laundry thinking about Thanksgiving and the past year. She was not looking forward to the holidays. The year had begun with such promise. Getting married on New Year’s Day seemed like a paradisiacal way to start her life with Jack. While the wedding couldn’t have been more perfect, she now realized that the reception really provided an insight into Jack’s family. A scene at the reception convinced her that Jack’s uncle Earl was an alcoholic. Her new father-in-law continually grumbled about the new laws that banned smoking indoors. “This family is so different from mine,” she thought. She was glad that she and Jack had decided to mix business with pleasure when they scheduled their wedding and honeymoon trip to coincide with his business trip to China the first week of January. Since his job frequently took him to all corners of the globe, she could only imagine that this trip would be the first of many. That idea quickly changed when she read the word 'pregnant' on the Clearblue Easy Digital home pregnancy test, just one week after returning from her honeymoon. While her pregnancy seemed to be progressing normally, by her seventh month, she began to experience a variety of health complications. It didn’t come as a surprise when she gave birth prematurely at 8 months to a healthy baby girl on August 15th. What was a surprise was the rapidity at which her newborn went from being healthy to being seriously ill. She was extremely thankful for the care that Fredrica received in the intensive care. It seemed that Fredrica had acquired a group B streptococcal infection during childbirth. Prompt intravenous treatment with amoxicillin and a week in neonatal ICU had saved her life. Thankfully, her doctor told her that Fredrica would most likely suffer no permanent damage from this infection. After Fredrica was discharged from the ICU, Wanda was extremely protective of Fredrica. However, it seemed that every other week, Fredrica required a visit to Dr. Lecter, her pediatrician. She seemed to be one of those infants prone to recurrent ear infections. Jack was due home from work at 4:00. They were going to do some final holiday shopping. Four o'clock seemed so far away. Fredrica seemed to be unusually irritable today. Wanda wished she had taken a Microbiology class in college. Then at least, she would know what was causing Fredrica's ear infections and what she could do about it. Well, at least she had the internet. She decided to Google “Ear infections.” That should provide the answer. “4,710,000 hits,” she muttered. “How can I make sense of it all?” She scrolled through a few pages, and one caught her eye, “Complications associated with chronic ear infections.” She clicked on this site and read that children with recurrent ear infections are susceptible to increased risk of meningitis and brain abscesses. They can also develop facial nerve paralysis and hearing loss with or without speech delays. Some children suffer permanent hearing loss. Treatment for chronic ear infections included surgery. In a panic, she called Dr. Lecter. “What is wrong with Fredrica?” “If she has a fever, you should bring her in for an exam today,” said Dr. Lecter. After an exam Dr. Lecter explained: “Fredrica is suffering from acute otitis media (a middle ear infection).” This is a common childhood ailment. Here are the signs supporting this diagnosis ? a fever of 101 o F ? the presence of fluid and pus in the middle ear ? redness of the eardrum. “What causes otitis media, Dr. Lecter?” asked Wanda. Dr. Lecter responded: “Some bacteria and some viruses can cause otitis media. Bacteria such as Streptococcus pneumoniae and Haemophilus influenzae account for most of the bacterial cases. The infection itself and the response of Fredrica’s immune system to the infection are causing her eustachian tube to become inflamed and painful. Often this condition doesn’t require treatment, but when there is a fever involved, it is a good idea to give me a call. Some forms of otitis media require medical attention because the disease may be painful, and complications can arise such as meningitis, but that is quite rare. Some research indicates that recurrent ear infections can lead to hearing loss and in turn, delay in speech development, but again that is not common. Fortunately prompt treatment with amoxicillin usually clears up the infection within a few days. So here’s what we will do: give her a course of amoxicillin and monitor her progress. Her symptoms should disappear within a couple of days. We like to be very careful in prescribing antibiotics, but with Frederica’s history of infections, her age and her symptoms, antibiotics are the first course of treatment. What flavor do you think Fredrica would prefer?” “Bubble gum is her current favorite,” replied Wanda. “Will she need surgery?” “Are ear infections contagious? I mean, can I get sick from the bacteria causing this disease,” fretted Wanda. “Ear infections are usually not contagious. A cold may spread among children and predispose them to getting an ear infections,” reassured Dr. Lecter. “Will Fredrica loose her hearing?” “Only a very small number of children suffer any form of hearing loss.” “Will Fredrica need surgery?” “Although the infections are relatively easy to treat, if a child has had multiple ear infections that do not get better easily or has evidence of hearing loss or speech delay, I may suggest ear tube surgery (also called bilateral myringotomy and tubes, or BMT). During this surgery, small tubes called tympanostomy tubes are placed in the eardrums to ventilate the area behind the ear drum, the middle ear. Approximately 2 million tympanostomy tubes are placed in children in the United States each year to help chronic middle ear infections. Although ear tube surgery is a relatively common procedure, surgery is not the first choice of treatment for otitis media. Antibiotics are the first course of treatment for bacterial ear infections.”
PLEASE ANSWER THE QUESTIONS BELOW FROM THE ABOVE READING
Read Part 1 of the Case Study, then answer the PAK 3.1 questions and submit your answers as a word document.
3.1A Fredrica has an ear infection caused by Streptococcus pneumoniae. Why doesn’t she have pneumonia?
3.1B Is it likely that some of the students in BSCI283 have Streptococcus pneumoniae in their nasal cavities. Do you? How could you tell? If Streptococcus pneumoniae is in their (your) nasal cavities, why aren't they (you) sick?
3.1C What are some possible components of the pus found in Fredrica's middle ear? How would these components make her eardrum red? How would they cause her to have a fever?
3.1D Wanda believes that amoxicillin will always be able to cure Fredrica of her ear infections. What are two scenarios where this drug will not be useful for treating her otitis media?
Explanation / Answer
3.1A: Streptococcus pneumoniae is a Gram positive facultative anerobic non motile diplococcal bacterial which can cause Pneumonia, meningitits, bronchitis, rhinitis, sinusitis, otitis media, conjunctivitis, sepsis, osteomyelitis, septic arthritis, endocarditism peritonitis, pericarditis, cellulitis, brain abscess etc
In the given case, baby is already infected with Group B streptococcal infection during pregnancy and prone to ear infections. These may be attributed to the inflammation and edema that is developed during the infection. The inflammation to the eustachian tube reduces the normal function and reduces the ventilation to middle ear. As a compensatory mechanism air is absorbed into the middle ear causing negative pressure. It is because of this negative pressure, Bacteria are pulled into the Middle ear causing infection only to the ear but not the lungs.
Eventhough S pneumonia can develop Pneumonia, since the bacteria are lodged in the middle ear due to negative pressure, they became invasive at the place of their localisation, developing the ear infection in this give case
3.1 B:
Yes, it very likely that Streptococcus pneumoniae can reside in the nasal cavities, because the microorganism is colonized in respiratory tract, sinuses and nasal cavities healthy carriers without presenting any symptoms. Most of them are not sick, because of the immunity. In a healthy adult, the immune system is capable enough to combat S.pneumonia. But it becomes invasive in those individuals who are susceptible or lack immunity as seen in infants, children, elderly or immunocomprised patients like HIV infected.
This can be verified by the fact that Streptococcal infections are 30-100 fold higher in HIV infected individuals and the case which is presented here, where the baby girl whose immune system is not fully developed resulted in the infection
3.1 C:
Pus accumulated in the middle ear mainly consists of neutrophils, leucocytes, dead microorganisms, cytokines, autocoids etc. These trigger the immunological responses causing inflammation in the tympanic membrane. The polysaccharide capsule, pneumolysin of the S pneumonia prevent the phagocytosis by macrophages and lymphocyte proliferation respectively. These antigenic stimulus will alert the body's immune system further to reset the thermostat in Hypothalamus to rise the body temperature. Fever is a defensive mechanism deployed by the body to make the environment unfavorable for the growth of the microorganism(as the optimum temperature for their growth is 37 0C)
3.1 D:
Amoxicillin is always the primary Drug of choice for S. pneumonia induced Otitis media infection. Amoxicillin will eradicate the non penicillin resistant S.pneumonia and ineffective against resistant strains
So, the first scenario where it is not helpful is Penicillin resistant S. pneumonia
Second scenario is the condition where prolonged use of Ampicillin develops resistance (by pumping antibiotic out of the cell, altering the shape of the Penicillin binding protein with which the drug interacts, degradation of ampicillin, producing beta lactamase) among the existing susceptible S.pneumonia
In either case, Tympanocentesis is done and the antimicrobial suceptibilty of the microorganism is tested.
Emperically Ceftriaxone, Clindamycin or addition of Beta lactamase inhibitor(Clavulanic acid) to ampicillin can be used in the resistant cases
Other possible scenarios: As the baby's immune system is not fully developed, ear infections may reoccur with other bacteria like Hemophilus influenza, Moraxella catarrhalis or viruses like Respiratory Syncytial virus, Influenza virus, enterovirus, rhinovirus or rarely by mycoplasma, chlamydia for which Amoxicillin may not be effective. Specific identification of the causative organism and its susceptibility testing help us to select effective antibiotic
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