Definition
A.An infection of the lungs that can have varying degrees of severity.
B.Caused by bacteria, viruses, or fungi.
C.Can be further divided into four types: Community, hospital, ventilator acquired, and aspiration.
Incidence
A.Pneumonia (combined with influenza) is the eighth leading cause of mortality in the United States, accounting for approximately 50,000 deaths annually.
B.Thirty-day mortality is higher in elderly patients treated for hospital-acquired pneumonia (HAP) compared to community-acquired pneumonia (CAP).
C.Pneumonia is the third leading cause of ED visits that led to a hospitalization, with the highest prevalence in patients 65 to 84 years.
D.It is the most common cause of readmissions for the elderly population.
E.It accounts for the top 10 most costly hospitalizations in the United States, with approximately $10.6 billion spent for 1.1 million hospital stays.
F.Most common cause of sepsis and septic shock.
Pathogenesis
A.A pathogenic microorganism invades the lung parenchyma. Neutrophils aggregate to the site of invasion and begin to phagocytize the microorganisms and release an extracellular trap.
B.The immune response is activated. Inflammatory mediators are released, causing the capillaries to become permeable and an exudative fluid to be formed. The protein rich fluid containing neutrophils, bacteria, fibrin, and so forth, fills the alveoli, leading to a lung consolidation.
Predisposing Factors
A.An impaired immune response and/or dysfunction of the body’s defense mechanism, HIV.
B.Advanced age.
C.Smoking.
D.Chronic lung disease (e.g., chronic obstructive pulmonary disease [COPD] and asthma).
E.Other chronic comorbid conditions (e.g., heart failure, diabetes).
F.Recent respiratory viral infection.
G.Excessive alcohol consumption.
Subjective Data
A.Common complaints/symptoms.
1.Cough with sputum production (see Figure 2.3).
2.Fever.
3.Chills.
4.Altered mental status or confusion, especially in the elderly.
5.Pleuritic chest pain.
B.Common/typical scenario.
1.Patients typically present with sudden onset of symptoms such as shortness of breath, productive cough, and fever. They may also complain of chills and malaise.
C.Family and social history.
May be more prevalent in smokers, among the elderly, and in the chronically ill.
D.Review of symptoms.
1.Symptoms may vary depending on the age, activity level, and underlying comorbid conditions. Elderly people typically present differently than younger adults.
2.The provider should inquire about onset, severity, and associated symptoms.
3.Assessment of recent respiratory viral illnesses is important, especially given the correlation of pneumonia following influenza.
4.It may help to enquire about recent sick contacts.
Physical Examination
A.General: Vital signs.
1.Fever, which may occur. Note that approximately 30% of patients are afebrile on presentation.
2.Tachycardia, which may or may not be present.
3.Possibly high respiratory rate; this may be normal or increased.
B.Neurological.
1.More likely to see changes in the elderly. Patients can be described as having confusion, decreased interactions, and/or acting differently.
C.Respiratory.
1.Rales/crackles on auscultation in the affected area. Patients may also have rhonchi.
2.Dullness on percussion in the affected area.
3.Increased tactile fremitus in the affected area.
4.Possible pleural friction rub.
5.Decreased breath sounds.
D.Possible other findings.
1.Cyanosis, respiratory failure, and septic shock in patients with a more virulent type of pneumonia, multilobar pneumonia, age, and/or comorbid conditions.
Diagnostic Tests
A.Chest x-ray.
1.Evidence of an infiltrate, which can be patchy or a dense consolidation of a lobe(s) or segment.
B.Sputum culture and gram stain.
1.Used to identify the microorganism responsible for the pneumonia.
2.Most sensitive if the patient can provide an adequate specimen and has not recently been treated or is not currently receiving treatment with antibiotics.
3.Intubated patient: Obtain an endotracheal aspirate.
C.Blood cultures.
1.Usually indicated for patients with more severe forms of pneumonia, specifically CAP.
2.Most common pathogen isolated in patients with CAP: Streptococcus pneumoniae. However, in more severe infections, other microorganisms may be present.
D.Urinary antigen testing.
1.Used to assess for pneumococcal pneumonia, mycoplasma pneumonia, and Legionnaire’s disease.
2.Rapid and simple; however, do not provide information for narrowing of antibiotics.
E.Serum procalcitonin.
1.Can assist the provider with antibiotic duration in conjunction with the patient’s clinical presentation.
2.No recommended use of procalcitonin in patients with hospital or ventilator-acquired pneumonia according to Infectious Diseases Society of America and the American Thoracic Society guidelines.
F.Comprehensive metabolic panel.
1.Can assist with risk stratification and sequela of pneumonia.
G.Complete blood count.
1.Assessment of a leukocytosis or leukopenia.
H.Arterial blood gas (ABG).
1.May be indicated in more severe presentations such as cyanosis or respiratory failure to evaluate for hypoxemia and/or hypercapnia.
I.Chest CT scan.
1.Not typically indicated, especially if one is able to obtain a good-quality chest x-ray.
Differential Diagnosis
A.COPD.
B.Asthma.
C.Pulmonary edema.
D.Bronchiectasis.
E.Lung cancer.
F.Pulmonary embolism.
G.Bronchitis.
H.Viral or bacterial pneumonia.
I.Pneumocystis pneumonia (PCP).
Evaluation and Management Plan
A.General plan.
1.Management of pneumonia: Dependent on the severity of the disease, classification or type of pneumonia (e.g., community vs. hospital acquired), and pathogens involved.
2.Supportive care, such as oxygen therapy or other methods of respiratory support (e.g., noninvasive ventilation, invasive mechanical ventilation); this should be considered in those patients with hypoxemia and/or respiratory failure.
3.Patients presenting with sepsis due to pneumonia. These patients should receive care in accordance with the sepsis guidelines.
4.Guidelines suggest that antimicrobial therapy be de-escalated rather than fixed therapy.
5.Transitioning to oral therapy. Oral therapy is appropriate once patients’ clinical status has improved, and they are hemodynamically stable.
6.Patients with coexisting Influenza A. Early treatment with oseltamivir or zanamivir is appropriate.
7.Systematic corticosteroids: May be appropriate in certain patient populations who present with severe CAP.
B.CAP.
1.Evaluation of patients for hospital admission. Use the CURB-65 criteria, which evaluates/looks at confusion, uremia, respiratory rate, low blood pressure, and age 65 years or greater, or pneumonia severity index (PSI) to identify patients who can be treated as outpatient versus inpatient.
2.Duration of treatment. Patients should receive a minimum of 5 days of treatment and literature suggests that more than 7 days is typically not needed.