Abscess. An abscess in the lung is a thick-walled, pus-filled cavity that forms when infection has destroyed lung tissue. It is more commonly seen with aspiration pneumonia, when a mixture of organisms is carried into the lung. Untreated abscesses can cause hemorrhage (bleeding) in the lung, but targeted antibiotic therapy significantly reduces the danger. Drainage with a needle may also be needed. Abscesses are more common with Staphylococcus aureus, Pseudomonas aeruginosa, or Klebsiella pneumoniae, and are uncommon with Streptococcus pneumoniae.
Respiratory Failure. Respiratory failure is one of the top causes of death in patients with more severe pneumonia. Acute respiratory distress syndrome (ARDS) is the specific condition that occurs when the lungs are unable to function and oxygen is so severely reduced that the patient's life is at risk. Failure can occur if pneumonia leads to physical changes in the lungs that make it even harder for the lungs to exchange oxygen (ventilatory failure).
Bacteremia. Bacteremia -- bacteria in the blood -- is the most common complication of pneumococcus infection, although it rarely spreads to other sites. Bacteremia is a frequent complication of infection from Gram-negative organisms, including Haemophilus influenzae.
Pleural Effusions and Empyema. The pleura is a two-layered membrane that surrounds each lung.
In some cases of pneumonia the pleura become inflamed, which can result in breathlessness and chest pain when breathing.
In about 20% of pneumonia cases fluid builds up between the pleural membranes, a condition known as pleural effusion. Ordinarily, the narrow zone between the two membranes contains only a tiny amount of fluid, which lubricates the lungs.
In most cases, particularly in Streptococcus pneumoniae, the fluid remains sterile (no bacteria are present), but occasionally it can become infected and even filled with pus, a condition called empyema. Empyema is more likely to occur with specific organisms such as Staphylococcus aureus or Klebsiella pneumoniae infections. The condition can cause permanent scarring.
Collapsed Lung. In some cases, air may fill up the area between the pleural membranes, causing the lungs to collapse. This is called pneumothorax. It may be a complication of pneumonia (particularly Streptococcus pneumoniae) or of the invasive procedures used to treat pleural effusion. Pneumothorax occurs when air leaks from inside the lung to the space between the lung and the chest wall. The lung then collapses. The dark side of the chest (right side of the picture) fills with air from outside of the lung tissue. Pneumothorax - chest X-ray
Other Complications of Pneumonia. In rare cases, infection may spread from the lungs to the heart and possibly throughout the body. This can cause abscesses in the brain and other organs. At least one study has also linked bacterial pneumonia with an increased risk of acute heart problems, such as heart attack or abnormal heart rhythm (arrhythmia).
Kidney complications and electrolyte imbalances are common in patients admitted to the hospital with pneumonia. If not treated, these problems cause more severe illness and increase the risk of death. Hydration through a vein (intravenous) controls the problem. Long-Term Effects of Atypical Pneumonias
Pneumonias cased by the atypical organisms mycoplasma and chlamydia are usually mild. Atherosclerosis of internal carotid artery
Atherosclerosis of internal carotid artery Click the icon to see an image of atherosclerosis of the internal carotid artery.
Asthma. Chlamydia pneumoniae, Mycoplasma pneumoniae, and RSV are becoming suspects in many cases of severe adult asthma.