This document provides an overview of pneumonia including its definition, classification, risk factors, signs and symptoms, diagnostic tests, management, nursing care, prevention, and complications. Pneumonia is an infection and inflammation of the lung tissues that impairs gas exchange and is a common cause of mortality in young children and the elderly. It can be caused by viruses, bacteria, fungi or other pathogens. Diagnosis involves physical exam, chest imaging, and laboratory tests. Treatment consists of antibiotics, oxygen therapy, respiratory support and addressing complications. Nursing care focuses on respiratory assessment, airway clearance techniques, rest, pain management, and patient education.