CXR: bilateral patchy opacities, small-moderate left pleural effusion
CT chest: RLL mass and cavitary nodules
Answer B
Fungi: Aspergillus spp, Coccidioides spp, Histoplasma spp, Blastomyces dermatitidis, Cryptococcus spp, agents of mucormycosis, Pneumocystis jirovecii (formerly P. carinii)
Parasites: Entamoeba histolytica Paragonimus westermani
Non-infectious diseases Pulmonary embolism with infarction, Vasculitis (eg, granulomatosis with polyangiitis), Neoplasm, Pulmonary sequestration, Bullae or cysts with air fluid level, Bronchiectasis, Cryptogenic organizing pneumonia, Sarcoidosis, Rheumatoid nodules, Pulmonary Langerhans histiocytosis, Foreign body aspiration
postinfluenza, prior antimicrobial treatment, or pulmonary comorbidities
UpToDate: Several studies suggested that the tendency to necrotizing pneumonia may be mediated by PVL, which is typically present in CA-MRSA strains [75-77,81-83,85-87]. However, subsequent reports have disproven the role of PVL as a virulence factor in MRSA pneumonia [88-92]. PVL is a cytotoxin that causes leukocyte destruction and tissue necrosis.
Procalcitonin use in lower respiratory tract infections
Other common features are gastrointestinal symptoms (nausea, vomiting, diarrhea) and mental status changes. Chest pain occurs in 30 percent of cases, chills in 40 to 50 percent, and rigors in 15 percent.
CLINICAL EVALUATION — Common clinical features of CAP include cough, fever, pleuritic chest pain, dyspnea, and sputum production. Mucopurulent sputum production is most frequently found in association with bacterial pneumonia, while scant or watery sputum production is more suggestive of an atypical pathogen. Although there are classic descriptions of certain types of sputum production and particular pathogens (eg, pneumococcal pneumonia and rust-colored sputum), these clinical descriptions do not help in clinical decision-making regarding treatment because they are rarely seen.
Other common features are gastrointestinal symptoms (nausea, vomiting, diarrhea) and mental status changes. Chest pain occurs in 30 percent of cases, chills in 40 to 50 percent, and rigors in 15 percent. Because of the rapid onset of symptoms, most individuals seek medical care within the first few days [4].
On physical examination, approximately 80 percent are febrile, although this finding is frequently absent in older patients, and temperature may be deceptively low in the morning due to normal diurnal variation. A respiratory rate above 24 breaths/minute is noted in 45 to 70 percent of patients and may be the most sensitive sign in older adult patients; tachycardia is also common. Chest examination reveals audible crackles in most patients. Signs of consolidation, such as decreased or bronchial breath sounds, dullness to percussion, tactile fremitus, and egophony are present in approximately one-third.
The major blood test abnormality is leukocytosis (typically between 15,000 and 30,000 per mm3) with a leftward shift. Leukopenia can occur and generally connotes a poor prognosis.
While the clinical features outlined above support the diagnosis of pneumonia, no clear constellation of symptoms and signs has been found to accurately predict whether or not the patient has pneumonia [5,6]. As an example, the sensitivity of the combination of fever, cough, tachycardia, and crackles was less than 50 percent when chest radiograph was used as a reference standard [5].
Not very specific for PNA.
Answer D.
Many signs are very specific for pneumonia but none are sensitive.
Crackles: caused by delayed opening of alveoli in deflated regions of pathologically inflamed lung
Classic physical findings are accurate signs of pneumonia when present absence does not affect the probability of disease
Help triage patients No clear constellation of symptoms and signs has been found to accurately predict whether or not the patient has pneumonia
appear in only the minority of patients with proven pneumonia;
Curb65 triage of patients
AFB cx: negative
Pneumocystis stain: negative
Fungal cx: 2+ yeast
Legionella urine Ag: negative
Strep pneumo urine Ag: negative
The presence of an infiltrate on plain chest radiograph is considered the gold standard for diagnosing pneumonia when clinical and microbiologic features are supportive. A chest radiograph should be obtained in patients with suspected pneumonia when possible; a demonstrable infiltrate by chest radiograph or other imaging technique is required for the diagnosis of pneumonia, according to the 2007 consensus guidelines from the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) [1].
The radiographic appearance of CAP may include lobar consolidation (image 1 and image 2), interstitial infiltrates (image 3 and image 4 and image 5), and/or cavitation (image 6).
Microbiologic testing is reserved for hospitalized patients (table 1) and for selected outpatients in whom test results would change management.
Methicillin-susceptible Staphylococcus aureus — If a sputum culture reveals MSSA, empiric therapy for MRSA should be replaced with nafcillin (2 g IV every four hours), oxacillin (2 g IV every four hours), or cefazolin (2 g IV every eight hours) [1].
Early discontinuation
7 days
10-21 days
S. pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, group A streptococci, mouth anaerobes, Legionella spp, Mycoplasma pneumoniae, Chlamydophila pneumoniae…
The presence of an infiltrate on plain chest radiograph is considered the gold standard for diagnosing pneumonia when clinical and microbiologic features are supportive. A chest radiograph should be obtained in patients with suspected pneumonia when possible; a demonstrable infiltrate by chest radiograph or other imaging technique is required for the diagnosis of pneumonia, according to the 2007 consensus guidelines from the Infectious Diseases Society of America (IDSA) and the American Thoracic Society (ATS) [1].
The radiographic appearance of CAP may include lobar consolidation (image 1 and image 2), interstitial infiltrates (image 3 and image 4 and image 5), and/or cavitation (image 6).
Microbiologic testing is reserved for hospitalized patients (table 1) and for selected outpatients in whom test results would change management.
Methicillin-susceptible Staphylococcus aureus — If a sputum culture reveals MSSA, empiric therapy for MRSA should be replaced with nafcillin (2 g IV every four hours), oxacillin (2 g IV every four hours), or cefazolin (2 g IV every eight hours) [1].
