Case 1: An 83-year old female was admitted to the hospital with fever and pyuria and a PMH of pneumonia and multiple pressure sores. She had recently had a foley catheter placed and was suspected of having a UTI based on clinical signs. A urine culture was performed and there was polymicrobial growth (too many types of organisms), so it did not help to narrow her diagnosis. Her sputum culture was positive for XDRAB (Extensively Drug Resistant Acinetobacter baumannii), an organism that we have not extensively studied in school yet. It is a gram-negative, oxidase-negative, cocobacillus that is an opportunistic organism and typically presents as a nosocomial infection along with other ESKAPE pathogens (E. faecium, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and other Enterobacter spp). These organisms have a high rate of drug resistance, but of them all, A.baumanii is most likely to be pan-drug resistant. Besides the commonality of gram-negative virulence factors, there are some other special qualities that allows it to persist in the human body. AbaR resistance islands give this bacteria the ability to resist multiple antibiotic classes (aminoglycosides, teracycline, and chloraminophenol to name a few). Because these islands are able to be conferred through horizontal transfer, resistance strains can be easily made. Carbapenems, which are often used as a last resort antibiotic, is uneffective in treating for this type of infection. However, some genius found out that an old drug is still effective against this bacteria, colistin. It is a polymxin, a type of antibiotic, that disrupts the bacterial cell membrane by interacting with the specific liposaccharide molecule that most gram-negative bacteria share in their outer membrane. However, there was a reason why they became less popular decades ago - it has extensive neurotoxicity and nephrotoxicity. For these reasons, it is used only as an antibiotic of last resort. Another drug that potentially can treat XDRAB infections is tigecycline, which is a tetracycline that we have already studied. However, Dr. Yu proposed that prior to initiating this treatment, they would wean off her antibiotic dosage therapy in hopes of other "good" bacteria colonizing the respiratory tract and outcompeting the XDRAB bacteria.
Case 2: An 86-year old male came into presenting with fever and dyspnea and a PMH of prior CVA, CHF, and ARF. Based on clinical lab data and chest x-rays, it was determined that he had a LUL bacterial pneumonia leading to sepsis, which gave him a P. aeruginosa UTI. Hebesser (Diltaziem HCl), a Ca channel blocker, was used to manage his hypertension and ARF while Cefulin (Ceftazidime), a third gen cephalosporin, was initiated to treat his sepsis and pneumonia. One of the interesting parts of the case was not the presentation and treatment itself, but the laboratory test that was used to determine the bacterial infection. Dr. Yu ordered a serum procalcitonin test. It is a biomarker that identifies patients with sepsis. Although broth culture method is the current gold standard, it takes at least 24 hours or more before a conclusive diagnosis. Elevated levels of procalcitonin can indicate systemic bacterial infections and due to its short half life (25-30 hours in plasma) coupled with its absence in health gives it a clear advantage over other biomarker tests. Although its physicological role still remains a mystery, there is a growing trend to use this test.
During the afternoon, we discussed various resolved cases that Dr. Yu thought were interesting and notable. Among those, the one that stood out for me:
Case 3: An (oldish) male came in with left sided chest pain (I thought he had unstable angina since he has pain all the time). On his chest x-ray, there was a large LUL consolidation consistent with a lesion or infiltrate suggesting that it could be either a pneumonia, neoplasm, pleural effusion, among other differentials. However, he did not have any fever or any typical presentation to suggest any of the current differentials, so Dr. Yu ordered a CT scan. Looking through it, what he had found was something even he did not take account for - it was an aortic dissection that grew and started pushing into the left lung field. As a result, he consulted with a cardiac surgeon and an intravascular stent was placed in the aortic arch region to stabilize the dissection. This was fascinating because something that might have suggested something wrong in the pulmonary region was in fact the cardiac region!
There were also many cases of COPD that he was involved with. As he explained his treatment strategy for each of his patients, the GOLD criteria and treatment differed a bit from what we had learned in school. He explained that what we had learned was true years ago, but was not the most current algorithm right now. Summarized below is the 2014 GOLD criteria and treatment options (http://www.goldcopd.org/uploads/users/files/GOLD_Pocket_2014_Jun11.pdf):
What a difference a couple of years makes! At the end of the day, both Christine and I were extremely grateful for the thoughtful and creative process that Dr. Yu showed us. I never really considered Pulmonology as a specific speciality that I would specialize in the future, but the quick pace and caring nature of the medical staff in this department left a positive impression on me.
Personal note: Dr. Yu took much more time and educated his patients and their families than what I would consider to be the average allotted time (2-3 minutes). It was refreshing to see this and it seemed that he was happy about this as well even though it might have slowed his progress during rounds. This is exactly the kind of philosophy that I want to advocate in the future!
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