Pneumonia is defined as inflammation of the lung tissue, often caused by an infection.  Infectious pneumonia may be caused by respiratory viruses or less-commonly bacteria.  Other causes of pneumonia include aspiration of food or stomach contents, toxic inhalation, airway foreign body, or asthma.  Respiratory viruses are common causes of pneumonia, especially in young children.  They include RSV, influenza, parainfluenza, and adenovirus.  Bacterial causes include Streptococcus pneumoniae, Streptococcus pyogenes, and Staphylococcus aureus.  Mycoplasma pneumonia is a unique bacteria that is the most common cause of pneumonia in older children.  Symptoms of pneumonia include cough, fever and malaise.  Treatment of viral pneumonia is mostly supportive while the mainstay of treatment for bacterial pneumonia is antibiotics.  Full recovery is expected in the great majority of cases, however complications are possible.

What is pneumonia?

Pneumonia is inflammation of the lungs.  It may occur on one or both sides and is typically caused by an infection.  Aspiration of a noxious substance or blockage of the airway may also cause pneumonia. 

What causes pneumonia?

Viruses

• Respiratory synctial virus (RSV) - the most common viral cause in young children
• Influenza
• Parainfluenza
• Adenovirus

Bacteria

• Streptococcus pneumoniae
• Streptococcus pyogenes
• Staphylococcus aureus
• Mycoplasma pneumoniae

Other

• Foreign body aspiration
• Aspiration of food, drink, or stomach contents
• Inhalation of a toxic substance
• Asthma - airway inflammation and blockage
• Fungi
• Parasites

What are the symptoms of pneumonia?

Symptoms of an upper respiratory tract infection often develop first (i.e., cough, runny or stuffy nose, mild fever).

• Cough
• Fever
• Malaise (feeling sick)
• Rapid breathing
• Chills

Red Flags (seek medical care immediately)

• Severe or persistent symptoms
• Infants and young children
• Breathing difficulty or rapid breathing
• Inward movement of the chest with breathing (extreme effort required to breath)
• Blue or pale appearance
• Ill-appearing child
• Not drinking fluids or not keeping them down
• Decreased urine output
• Excessive sleepiness, confusion or unusual behavior

How is pneumonia diagnosed?

Chest exam with a stethoscope reveals decreased breath sounds on the affected side, crackles, or wheezing.  Tapping on the chest may reveal a dull sound when compared to a healthy lung.  Voice sounds heard through the stethoscope may sound different in an affected lung.  Findings of fever, cough, and changes in vital signs support the diagnosis.

A chest x-ray is the standard imaging study for confirming the diagnosis of pneumonia.  Fluid outside of the lung may also be seen on x-ray.

Computed tomography (CT scan) shows the extent of pneumonia well, however this study is reserved for complicated or severe cases.

Pulse oximetry may reveal decreased oxygenation of blood, especially in severe disease.

Blood tests may be performed in ill children.  Rarely blood cultures will identify the offending bacteria.  The white blood count is often elevated.  Inflammatory markers such as erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP), and the platelet count are often elevated.  In severe disease

How is pneumonia treated?

Supportive care includes:

• Supplemental oxygen and respiratory support if necessary
• Intravenous fluids
• Anti-fever medicines (i.e., ibuprophen or acetaminophen)
• Cough medicines and decongestants

Treatment of viral pneumonia is mostly supportive.  Influenza may be treated with antiviral medications if diagnosed early. 

Bacterial pneumonia is typically treated with an antibiotic such as penicillin, a cephalosporin, or a fluoroquinolone.  In severe cases, an intravenous antibiotic such as vancomycin or a combination of antibiotics may be used. 

Mycoplasma pneumonia is a bacteria that does not have a cell wall (the target of many antibiotics), therefore a special antibiotic such as azithromycin may be used.

What are the possible complications of pneumonia?

With appropriate treatment, complications are rare.  Complications include:

• Empyema - pus collection in the pleural space outside the lungs
• Bacteremia or sepsis
• Respiratory failure