12th January 2024

Complications

A number of complications can result from pneumonia. Type 1 respiratory failure, with a PₐO₂ < 8, is common due to the impedance of oxygen diffusion across pus/fluid in the alveolar spaces. Inflammation of the pleura due to the infection can cause an exudative pleural effusion to develop. Small pleural effusions may be of no consequence; however, drainage may be required if the effusion becomes large and leads to symptoms. Additionally, if the effusion becomes infected with pus in the pleural space (empyema), this must also be drained. An empyema should be suspected in patients with evidence of pleural effusion on a chest X-ray and recurrent fevers despite treatment of their pneumonia. Aspirated pleural fluid is classically yellow and turbid, with a pH < 7.2 being diagnostic of empyema. Additional complications of pneumonia include sepsis and the development of lung abscesses, which typically cause a swinging fever.

Image Source: Wikimedia Commons (2017). Left-sided Pleural Effusion, Licensed under a creative commons licence. Available for free at :https://upload.wikimedia.org/wikipedia/commons/5/57/Left-sided_Pleural_Effusion.jpg (Accessed: 22 February  2022).