Chlamydia pneumonia is an infectious lung disease caused by any of the Chlamydia group of bacteria. There are three different types of Chlamydia bacteria: C pneumoniae, C psittaci and C trachomatis. While C trachomatis is a common cause of sexually transmitted disease, babies can catch the infection from their mothers and this sometimes develops into pneumonia. C psittaci causes an infection in birds which may be passed on to humans, leading to a Chlamydia pneumonia which can range from symptomless to severe. Chlamydial pneumonia caused by C pneumoniae tends to be milder in younger adults, but may occasionally be more serious in elderly people.
There are many different types of pneumonia and it can be caused by viruses, parasites and fungi as well as by bacteria like Chlamydia. Of the three types of Chlamydia, C pneumoniae is the one most commonly found to cause infections. As well as causing Chlamydia pneumonia, it can cause milder diseases such as bronchitis or inflammation of the airways.
The symptoms of Chlamydia pneumonia can differ depending on which one of the Chlamydia bacteria is causing the infection. In the case of C pneumoniae there may be no symptoms in mild cases, or the disease may at first appear similar to the common cold, with a runny nose, sore throat and hoarse voice. Pneumonia symptoms of cough, weakness and chest pain may follow, sometimes accompanied by headaches.
C psittaci pneumonia symptoms may develop up to two weeks after contact with infected birds. There is often a cough, without any phlegm, together with pain in the chest. In more severe cases, the person may have a high fever, and the infection may go on to affect the brain and the rest of the body, sometimes causing seizures.
At first, a stuffy or runny nose, breathlessness and a cough may be seen in babies infected with C trachomatis. Chlamydia pneumonia may develop later, and around half of babies will have associated eye or ear infections. In most cases the illness is only mild but, if it is left untreated, there is a small risk of complications resulting in serious breathing difficulties.
Treating Chlamydia pneumonia generally involves giving antibiotics, with different drugs used for each strain of Chlamydia bacteria. Depending on the severity of the pneumonia, it may be necessary for the person to be admitted to the hospital, and pain relief, fluids and oxygen may be required. For older, more frail people and those with other medical conditions, hospital treatment is more likely.