Pneumonia - Community-Acquired Disease Summary

Last updated: 31 March 2025

Content on this page:

Content on this page:

Overview

Pneumonia is an acute infection of the pulmonary parenchyma accompanied by symptoms of acute illness and abnormal chest findings. It is further described in the Introduction section.

Pneumonia is still the leading cause of death from an infectious disease in adults and children. A detailed discussion about the prevalence of pneumonia in the region is in the Epidemiology section.

The most frequently isolated organism in patients with community-acquired pneumonia is Streptococcus pneumoniae. Other commonly identified pathogens are enumerated in the Etiology section.  

The Pathophysiology section identifies the mechanisms involved when a patient is infected with pneumonia. The section also mentions the virulence factors of some of the causative agents of community-acquired pneumonia.

The Risk Factors section identifies the various circumstances predisposing an individual to acquiring community-acquired pneumonia.

Depending on the patient’s overall clinical status, vital signs, presence of co-morbidities, and chest X-ray findings, the patient may be classified to have low-, moderate- or high-risk community-acquired pneumonia.  The Classification section describes each of these types.

History and Physical Examination

The Clinical Presentation section describes the respiratory symptoms and other signs and symptoms of patients with community-acquired pneumonia. This section also discusses the typical presentation of each type of community-acquired pneumonia.

Diagnosis

In the Diagnosis and Diagnostic Criteria section, factors to consider in the definite diagnosis of community-acquired pneumonia are identified.

Several laboratory tests and imaging procedures serve as adjuncts in diagnosing pneumonia and they are enumerated in the Laboratory Tests and Ancillaries and Imaging sections.

Other diseases that can present with the same symptoms as pneumonia are listed in the Differential Diagnosis section.

Management

Patients with severe community-acquired pneumonia should be managed in a hospital setting. Indications for direct intensive care unit (ICU) admission are discussed in the Evaluation section. In this section also risk assessment and severity index tests are further elaborated.

Factors to consider in the treatment of patients with community-acquired pneumonia are in the Principles of Therapy section.

The Pharmacological Therapy section discusses in detail the recommended empiric antibiotic therapy and the duration of therapy based on etiology. Some of the supportive therapies are also mentioned.

The Nonpharmacological section includes things to educate the patient about the management of community-acquired pneumonia.  

Pneumococcal and influenza vaccines are employed in the prevention of community-acquired pneumonia. Details on these vaccines as well as smoking cessation are in the Prevention section.

The Monitoring section identifies the things to monitor for each type of pneumonia and discusses further treatment failure and criteria for discharge.