Community Acquired Pneumonia

hello on today's episode of intern crash course I'm discussing community-acquired pneumonia let's run through the common presenting features of community-acquired pneumonia historical features to argue in favor of cap include dyspnea cough particularly if it's productive fever and chills while features argue against cap include a sore throat and rhinorrhea both of which are associated with upper rather than lower respiratory tract infections exam findings typically include 2 Kip Nia tachycardia hypoxemia and fever focal lung findings include dullness to percussion decreased breath sounds bronchial breath sounds crackles and egophony and on labs the white blood cell count is usually elevated but can rarely be abnormally low when the pneumonia is severe enough to be accompanied by septic shock also a protein called procalcitonin has been found to be a nonspecific biomarker of bacterial infections importantly a diagnosis of pneumonia requires both a combination of clinical features and consistent imaging findings you should never make a diagnosis of pneumonia in the absence of lung imaging of some kind unless you are seeing patients at a location where imaging is just not available to understand the treatment you need to be aware of the common microbial ideologies of CAP the most common is streptococcus pneumonia more commonly known as pneumococcus other causes include homophily influenza a mycoplasma chlamydia pneumonia Legionella staph aureus with MSSA being more common than Mrs a and a variety of respiratory viruses most notably influenza their frequency of specific organisms is dependent upon the season geography patient population and the severity of illness I'll take a moment to discuss a few confusing points of terminology atypical pneumonia refers to a pneumonia in which systemic symptoms such as fever malaise and headache predominates over respiratory symptoms such as dyspnea the chest x-ray shows interstitial or patchy opacities rather than lobar ones and the illness is often but not always relatively mild in severity atypical bacteria are bacteria that grow poorly in routine culture media including mycoplasma chlamydia and Legionella unlike other bacterial causes of CAP atypical bacteria are also intrinsically resistant to beta-lactam antibiotics although it's more likely saying that a patient has atypical pneumonia does not necessarily imply the pneumonia is caused by an atypical bacteria and atypical whether referring to pneumonia or to bacteria does not imply uncommon in fact atypical bacteria are actually very common ideologies of community-acquired pneumonia one sort of related term that you will hear from time to time is walking pneumonia because of ambiguity with what it means it's not a useful medical term and should be avoided altogether finally healthcare-associated pneumonia or hCAP is an outdated term that should be avoided this new category of pneumonia was originally introduced by guidelines in 2005 and led to an increase in inappropriately broad antibiotic coverage exposing patients to avoidable side effects and promoting antibiotic resistance so as of 2016 the category of hCAP is no more so now what should be included in the evaluation of a patient with pneumonia as already mentioned pneumonia cannot be reliably diagnosed in the absence of a chest x-ray although there is a very small number of patients with clinical pneumonia and an initially unremarkable chest x-ray who will subsequently develop radiographic pneumonia over the next several days following illness onset all patients warrant a CBC and basic metabolic panel has an elevated white-blood-cell count supports the diagnosis while a low hematocrit and high B UN are negative prognostic markers that should be incorporated into triage decisions during flu season obtain a nasopharyngeal swab to test for influenza A nucleic acid amplification test including reverse transcriptase PCR is felt to be superior to antigen based tests if severe pneumonia is suspected in ABG is appropriate a low pao2 and low pH are also both negative prognostic markers that might impact the subsequent location of care and most patients with pneumonia severe enough to warrant inpatient admission also warrant an ECG as a number of cardiac ideologies can present with acute disney a' and even cough and because the ammonia can trigger several arrhythmias now for some tests that are sometimes appropriate but generally over-ordered first procalcitonin because it is believed to increase in response to bacterial infections and not viral ones it's frequently ordered to determine if antibiotics can be safely withheld however the 2019 joint IDSA ATS guidelines on community acquired pneumonia specifically recommend against this practice this is due to the observation that there is not a specific procalcitonin threshold which can reliably distinguish between bacterial and viral ideologies those same guidelines recommend testing for pneumococcal and Legionella urine antigens only in patients with severe pneumonia or in the case of Legionella if there is association to a possible outbreak blood cultures sputum Gram stain and sputum culture are recommended only for patients with severe pneumonia a history of prior M RSA or Pseudomonas infection and those who have received intravenous antibiotics within the last 90 days and those patients who are being empirically treated for either M RSA or Pseudomonas for some other reason last clinicians occasionally order multiplex respiratory viral panels on specimens obtained via nasopharyngeal swab in order to distinguish between viruses and bacteria however the literature on this practice is sparse and pneumonia guidelines they don't mention it at all so I just mentioned this term severe pneumonia which might have seemed like a vague term to mean a minim pneumonia that's really bad but in fact there are specific criteria used to define it which will be relevant when I discuss treatment the two major criteria for severe cap are septic shock and respiratory failure requiring mechanical ventilation the nine minor criteria respiratory rate of 30 or more a p2f ratio under 250 multi lowbar infiltrates confusion AB un of twenty or more an abnormally low white count a platelet count under 100,000 hypothermia and hypotension responsive to IV fluids severe cap is said to be present when at least one major criterion or at least three minor criteria are met in addition to the severe cap criteria there are two clinical prediction rules that are frequently used for prognostication and triage the simpler one is called curb 65 which is an acronym C for confusion you for uranium R for respiratory rates B for blood pressure meaning hypotension and patient age of 65 or more in its common use a patient with zero to one of these points is treated as an outpatient with two points they are either admitted to an inpatient unit or to an observation unit and anyone with three or more points is admitted to inpatient the other clinical prediction role is called the pneumonia severity index or psi you may still hear some older physicians refer to this as the port score for patient outcomes research team I'm not going to read through it because it's obviously more detailed but in comparison to the curb 65 it places greater weight on the age of the patients makes a distinction and risk between the two sexes and it places significant weight on elements of the past medical history but like the curb 65 the higher the patient's score the more acute the recommended location of treatment despite its complexity the IDSA and 80s recommend using the PSI over curb 65 for determining which patients can be safely treated as outpatients while the previous severe pneumonia criteria are best used to determine the appropriateness of an ICU admission now let's discuss antibiotic treatments these are also based on the reasons IDSA and ats guidelines treatment is divided into four categories outpatient without significant comorbidities outpatient with comorbidities inpatient non severe and inpatient severe and/or ICU for each category I'll mention the preferred options and then some additional considerations for outpatient without comorbidities preferred options include doxycycline and amoxicillin at first the amoxicillin might seem to be a strange choice here since it doesn't cover atypical bacteria at all the guidelines acknowledge this and reference outcome data demonstrating the effectiveness of amoxicillin nonetheless which to the best of my knowledge has no great explanation an additional consideration is that a macrolide such as a zero Meissen can be used but only if the local rate of pneumococcal resistance is under 25 percent which is essentially nowhere within the United States the next category outpatient with comorbidities these comorbidities include heart failure chronic lung disease cirrhosis CKD alcohol dependence active malignancy a spleen 'ya and diabetes preferred treatment options here are the combination of either amoxicillin clavulanic acid own as augmentin or cephalosporin such as cefotaxime with either a macrolide or doxycycline an acceptable alternative to this is mono therapy with a so-called respiratory fluoroquinolone which includes levofloxacin and moxifloxacin but not ciprofloxacin for in patients who don't meet severe criteria a moderately broad intravenous beta lactam is preferred such as ampicillin sawback them known as unison or ceftriaxone plus a macrolide or a respiratory fluoroquinolone as mono therapy the clinician should at mr saye coverage and or pseudomonas coverage if the patient has significant risk factors for those pathogens for those with severe pneumonia most of whom should be admitted to the ICU recommended regimens include a beta lactam plus macrolide as above or a beta lactam plus C respiratory fluoroquinolone no mono therapy here and once again and Mrs a and/or Pseudomonas coverage in the presence of risk factors the duration of antibiotic treatment should generally be 5 days or until clinical resolution whichever is longer exception to this include M RSA and Pseudomonas ammonia which experts recommend to be treated for at least 7 days and sometimes longer what are some of the reasons that a patient might fail to improve insufficient time has elapsed they've been prescribed and inadequate antibiotic dose they are infected with a resistant organism such as Mrs a they are infected with an unusual organism such as a gram-negative rod tuberculosis or pcp among others they have inadequate source control for example in untrained empyema or lung abscess or maybe the diagnosis of pneumonia is incorrect the most common diagnosis to mistake for pneumonia are pneumonitis heart failure pulmonary embolism and a COPD exacerbation some final considerations in cavitary pneumonia that is a pneumonia characterized by one or more cavities on chest x-ray considered tuberculosis fungal infections and nocardia as possible ideologies in immunocompromised patients also considered TB fungal infections again the cardia and PCP empiric and aerobic coverage in cases of suspected aspiration pneumonia is no longer recommended although there has been some research into the use of steroids in pneumococcal pneumonia guidelines at the present time recommend that steroids should only be used in the presence of refractory septic shock and last follow-up chest x-rays to confirm radiographic resolution of pneumonia is generally not necessary for most cases but you should consider a chest CT in smokers who meet guidelines for lung cancer screening [Music] you

Channel: Strong Medicine

Views: 68,751

Keywords: pneumonia, community acquired pneumonia, clinical reasoning, med ed, medical education, medical school, nursing school, antibiotics, infection, infectious diseases, pneumococcus, streptococcus, idsa guidelines, lung infection, lung

Id: Yxbju-UTeAY

Length: 13min 35sec (815 seconds)

Published: Wed Oct 30 2019