Chest X-Ray PA (Posterior-Anterior) of a male patient who presented with cough and fever. The purple arrows indicate right middle lobe pneumonia. Also noticeable are air bronchograms; an air bronchogram occurs when surrounding alveoli are filled with fluid or inflammatory fluids (in this case due to the infection) and a tubular outline of an airway is made visible. The indistinct borders around the consolidated area can distinguish pneumonia, or an infection of the lung, from a mass or tumour because the latter are usually more well-defined. Pneumonia is a lung infection associated on x-ray with consolidation. Consolidation refers to all lung abnormalities which increase density and show as opacities. A pulmonary consolidation refers to the filling of the alveoli and small airways with any fluid or dense material. Also visible is silhouetting of the right heart border, the ‘silhouette sign’ refers to the loss of normal borders between thoracic structures.(1) Diagnosis: Right Middle Lobe Pneumonia.
Pneumonia is an inflammation of the lung, particularly the alveoli which are the tiny air sacs at the end of the smallest airways where gaseous exchange occurs. Pneumonia is usually caused by an infection with a virus, bacteria, or more rarely, fungi. Pneumonia is classified in different ways; by the organism responsible for the disease, by the location of the infection in the lung or according to where it was acquired.(2)
There are four main types of pneumonia that are classified according to the causative organism; these are bacterial, viral, aspiration and fungal. The most common cause is a bacterial infection which is called pneumococcal pneumonia and the bacteria responsible is Streptococcus pneumonia. Other common bacteria are haemophilus influenzae, mycoplasma pneumonia (most common in infants and young children and tends to occur in outbreaks) and Staphylococcus aureus. Less commonly occurring pneumonias are caused by Chlamydophila psittaci, Chlamydophila pneumonia and Legionella pneumonia (responsible for Legionnaire’s disease).
Frontal Chest X-Ray in a 49-year-old woman with pneumococcal pneumonia. This chest x-ray shows a left lower lobe consolidation or opacity with pleural effusion. A pleural effusion is a buildup of excess fluid between layers of the tissue lining the lung and the chest cavity, if pneumonia is the cause it is known as a parapneumonic pleural effusion. These pleural effusions are common in cases of pneuonia, over 40% of patients with bacterial pneumonia and 60% of pneumococcal cases develop parapneumonic pleural effusions.(3) Findings: Pneumococcal Lower Lobe Pneumonia.
Pneumonia remains a common illness and a major cause of death among all age groups worldwide. Pneumonia is especially dangerous in those whose immune systems are weakened, for example the elderly or very young. The immune system can be weakened by underlying or pre-existing illness, malnutrition and environmental factors. In 2013 pneumonia killed 935,000 children under the age of five and accounts for 15% of all deaths in the same age range.(4) Worldwide, pneumonia affects around 450 million people a year and results in 4 million deaths which is around 7 % o the world’s yearly total.(5,6) Pneumonia is the main cause of death in children in low income countries. In 2008, 151 million children in the developing world were affected by pneumonia compared to 5 million in the developed world.(7)
1. Silouette Sign, 2008, Family Practice Notebook, LLC. Retrieved 9 February 2010.
2. Dunn, L (2005 Jun 29-Jul 5). ‘Pneumonia: classification, diagnosis and nursing management’. Nursing standard (Royal College of Nursing (Great Britain) : 1987) 19 (42): 50–4. doi:10.7748/ns2005.06.19.42.50.c3901. PMID 16013205.
3. Sahn SA. ‘Diagnosis and management of parapneumonic effusions and empyema’. Clin Infect Dis. Dec 1 2007;45(11):1480-6.
4. World Health Organisation (WHO): Pneumonia Fact sheet N°331 Updated November 2014
5,6,7 .Ruuskanen, O; Lahti, E; Jennings, LC; Murdoch, DR (2011-04-09). “Viral pneumonia.”. Lancet 377 (9773): 1264–75.