In addition, patients with atypical CAP may present with more subtle pulmonary findings, nonlobar infiltrates on radiography, and various extrapulmonary manifestations (eg, diarrhea, otalgia).Atypical CAP pathogens include the following: While historical clues and physical examination findings may suggest a causative pathogen, the clinical signs and symptoms of CAP are not sufficiently specific to reliably differentiate the exact etiologic agent.
Immunocompromised hosts who present with CAP are treated in the same manner as otherwise healthy hosts but may require a longer duration of therapy.
Investigations into pathogens associated with compromised hosts may need to be pursued. Numerous other organisms can cause CAP in the appropriate clinical setting.
However, with the advent of novel diagnostic technologies, viral respiratory tract infections are being identified as common etiologies of CAP.
The most common viral pathogens recovered from hospitalized patients admitted with CAP include human rhinovirus and influenza.
Serial chest radiography can be used to observe the progression of CAP; however, radiographic improvement may lag behind clinical improvement.
Critical Thinking Framework - Community Acquired Pneumonia Case Study Introduction
Multiple scoring systems are available to assess the severity of CAP and to assist in deciding whether a patient should be hospitalized or admitted to the intensive care unit (ICU).Furthermore, the so-called “atypical CAP” pathogens are actually common causes of CAP and were originally classified as atypical because they are not readily detectable on Gram stain or cultivatable on standard bacteriologic media.Severe CAP frequently develops in individuals with comorbid factors such as underlying cardiopulmonary disease, diminished splenic function, and/or heightened pathogenic virulence.In certain patients admitted to the ICU, the microbial etiology of pneumonia may be complex.In a study by Cilloniz et al, 11% of cases were polymicrobial.Patients should be afebrile for 48-72 hours and have no signs of instability before antibiotic therapy is stopped.The duration of therapy may need to be increased if the initial empiric therapy has no activity against the specific pathogen.Patients with typical CAP classically present with fever, a productive cough with purulent sputum, dyspnea, and pleuritic chest pain.Characteristic pulmonary findings on physical examination include the following: The clinical presentation of so-called “atypical” CAP is often subacute and frequently indolent.ICU admission should also be considered in patients with 3 or more minor risk factors, including respiratory rate of 30 or more, Pa O Proposed scoring systems may also be helpful in certain populations to predict the severity of CAP.The SMART-COP score emphasizes the ability to predict the need for ventilator or vasopressor support and includes systolic blood pressure, multilobar infiltrates, serum albumin levels, respiratory rate, tachycardia, confusion, oxygenation, and p H level.