Dr. Schiffman received his B.S. degree with High Honors in biology from Hobart College in 1976. He then moved to Chicago where he studied biochemistry at the University of Illinois, Chicago Circle. He attended Rush Medical College where he received his M.D. degree in 1982 and was elected to the Alpha Omega Alpha Medical Honor Society. He completed his Internal Medicine internship and residency at the University of California, Irvine.
Melissa Conrad Stöppler, MD, is a U.S. board-certified Anatomic Pathologist with subspecialty training in the fields of Experimental and Molecular Pathology. Dr. Stöppler's educational background includes a BA with Highest Distinction from the University of Virginia and an MD from the University of North Carolina. She completed residency training in Anatomic Pathology at Georgetown University followed by subspecialty fellowship training in molecular diagnostics and experimental pathology.
Pneumonia is an infection of the lungs. People with pneumonia usually complain
of coughing, mucus production, fever, shortness of breath, and/or chest pain.
The body's immune system usually keeps bacteria from infecting the lungs. In bacterial pneumonia, bacteria reproduce in
the lungs, while the body tries to fight off the infection. This response to bacterial invaders is called inflammation.
When the inflammation occurs in the alveoli (microscopic air sacs in the lungs) they fill with fluid.
The lungs become less elastic and cannot take oxygen into the blood or remove carbon dioxide from
the blood as efficiently as usual.
When the alveoli don't work efficiently, the lungs are less able to extract oxygen from the air. This causes the feeling of being short of breath (dyspnea), which is one of the most common symptoms of pneumonia. Inflammation
is the body's attempt to destroy infection, and causes many of the other symptoms
of bacterial pneumonia, including fever and chest pain.
Pneumonia can be very serious, because it directly
interferes with the body's ability to exchange carbon dioxide and oxygen.
Pneumonia is different from acute bronchitis
(another disease that can cause fever, cough, chest pain,
and shortness of breath) because acute bronchitis is caused by inflammation in the air
passages (called bronchi) leading to the alveoli, not the alveoli themselves. Sometimes it is very difficult, even for a doctor, to tell pneumonia and bronchitis apart. The symptoms and physical examination can be identical. Sometimes a
X-ray is the only way to distinguish
pneumonia from bronchitis. There is also an entity in which both the airways and air sacs are involved with infection, and this is referred to as bronchopneumonia.
Bacterial Pneumonia Causes
Most pneumonia is caused by bacteria or a virus. Pneumonia from
any cause can occur at any age, but people in certain age groups are at higher
risk for certain types of pneumonia.
The most common cause of bacterial pneumonia is a type of bacteria known as Streptococcus pneumoniae. Haemophilus influenzae, Chlamydia pneumoniae, Mycoplasma pneumoniae, and Legionella pneumophila are some other major bacteria that cause pneumonia.
People who inhale toxic materials can injure the lungs and cause chemical pneumonia. This is more accurately referred to as chemical pneumonitis, since the process is mainly due to inflammation not from an infectious source.
Fungi can also cause pneumonia. In certain areas of the United States, specific fungi are well known. Coccidioidomycosis, usually seen in the Southwest,
is a type of fungal infection that causes a pneumonia called "San Joaquin fever" or "Valley fever." Histoplasmosis (seen primarily in the Midwest) and blastomycosis (seen primarily in the Southeast) are
other fungal diseases that cause pneumonias.
The most common way you catch pneumonia is to aspirate bacteria from the upper airway, usually
the oral cavity. Other ways to catch pneumonia can be by breathing in infected air droplets from someone who has pneumonia. In some cases, the bacteria can be generated by an improperly cleaned air conditioner or
Jacuzzi. Yet another source of infection in the lungs is spread of an infection from somewhere else in
the body, such as the kidney. Bacteria can enter the bloodstream from any source and be deposited in the lungs, resulting in pneumonia.
The risk of catching pneumonia is determined by the specific bacteria, virus, or fungus, the number of
organisms the person inhales, and the body's ability to fight infections.
A person cannot "catch pneumonia" by not dressing properly for cold weather or by being caught in the rain.
Walking pneumonia: A lay term used to refer to atypical pneumonia. Pneumonia is an infection of the lung; atypical pneumonia refers to pneumonia caused by certain bacteria, including
Legionella pneumophila, Mycoplasma pneumoniae, and Chlamydophila pneumoniae. Typically, the pneumonia produced by
Mycoplasma and Chlamydophila is characterized by mild symptoms. The most common symptoms of pneumonia are chills and fever, shortness of breath, and cough. Muscle aches and loss of appetite are also common. Treatment involves antibiotics and fever-reducing medications.