Legionnaires' disease is a type of pneumonia that is in its most severe form. The disease occurs due to a bacterial infection caused by a bacteria called legionella and mainly results in the inflammation of the lungs. The bacteria are known to thrive commonly in areas such as plumbing, shower heads, and water tanks. Sometimes, legionella pneumonia can also result due to the bacteria living in air conditioner condensers and coolers. The bacteria often gets built up and travels through the mist that is sprayed through air conditioner ducts and settles in places like the walls of buildings. Long distance travelers are susceptible to acquiring an infection from the bacteria due to traveling long hours in the enclosed space of a plane.
Legionella bacteria thrive and multiply at very high temperatures close to 90 and 105 degrees. Hot water pipes, both industrial and residential, can also be a breeding ground for these bacteria. One can contract the bacterial infection by inhaling water droplets, such as during a shower in which there is bacteria growing in the shower head.
Legionnaires' disease is also known as Pontiac fever. It is one of the most critical forms of pneumonia that could require the patient to be treated in an intensive care unit. Each year, there are approximately 10 thousand to 18 thousand people suffering from this form of infection.
People with impaired or weak immune systems are more prone to the risk of complications. Also, smokers and senior citizens are more at risk of acquiring the infection.
What happens in Legionnaires' disease?
Legionnaires' is not an infection that one acquires due to direct contact with an infected person. It is rather a disease that one gets due to direct contact with the bacteria. Most people do not feel the symptoms of Legionnaires' at the start. The symptoms may appear really mild, so much so that a person may not even feel the need to visit a doctor. The disease, however, when left untreated, can develop into severe complications, including:
- Respiratory system failure: Excessive fluid built up in the lungs may result in a failure of the respiratory system. The infection in the lungs increases to such an extent that external help is needed and oxygen cannot be supplied to the entire body without help. Since breathing in these cases can get affected, patients are often moved into the ICU where breathing support is provided to help them breathe better. Doctors may also administer anesthesia to put the patients to sleep during this time.
- Impairment of the kidney: When the infection spreads beyond control, it can affect the functioning of the kidneys and the damage can be so severe that the kidneys may cease to work. The primary function of the kidneys is to clear and remove the toxins from the body by filtering the blood. A renal failure may result if the kidneys do not work properly.
- Severe sepsis or septic shock: A patient can go into a state of septic shock that causes a severe blood infection, which can result in low blood pressure and even multiple organ failure, leading to death.
Symptoms associated with Legionnaires' disease
The bacteria have an incubation period that ranges from two to 10 days. This is the period that starts from the bacterial infection being acquired to the bacteria developing in the system and showing its symptoms. In some cases, the time frame for the symptoms to show up can extend up to two weeks.
The first signs of the disease are the following:
- Persistent cough
- High fever
- Loss of appetite
- A general feeling of sickness as is seen in most cases of influenza
Along with the abovementioned symptoms, aches and pains including body pain and headaches are commonly seen in patients. Mucus or phlegm discharge may be discolored, often dark yellow or green, and in some cases having traces of blood.
Symptoms can worsen very quickly after the first signs of the disease are seen. The worsening becomes more drastic as the infection starts spreading from the lung tissue. Breathlessness, rapid breathing, and chest congestion are commonly seen. One experiences a slight pain on either side of the chest as he breathes, especially when taking deep breaths. This condition is known as pleuritic chest pain and normally occurs as the lung surfaces get inflamed due to the bacterial infection.
All these symptoms are very commonly seen in pneumonia arising from a lung infection. These are typical symptoms of pneumonia. Some of the other symptoms associated with the disease include a confused state of mind, nausea, vomiting, and diarrhea. In a fairly large number of people, the disease shows symptoms associated with the gut, or gastrointestinal tract. Severe complications could give rise to problems related to the heart, brain, kidney, and blood.
When you experience the first signs of the disease, you must visit your doctor for an early diagnosis and quick start of treatment before the condition worsens.
What is the diagnostic procedure for Legionnaires' disease?
- X-ray: An X-ray of the chest is usually used for confirming a diagnosis of lung infection or pneumonia. However, what one must know is that pneumonia is a medical condition arising from an infection. An X-ray indicates the pneumonia condition in the lungs, but does not an answer what type of bacteria or virus is causing the infection.
- Lab tests: Once the doctor confirms the pneumonia in the chest through an X-ray, a series of sample tests may be recommended. These tests include blood tests, phlegm tests, and so on to identify which bacteria is responsible for the pneumonia condition. The blood tests may also include various blood cultures wherein the researchers make the legionella bacteria survive and multiply so that they can be observed under a microscope. The next tests include testing antibodies that the legionella bacteria are sensitive to. Antibodies are made by our own immune system, and antibiotic medications can also increase antibodies to fight the infection.
- Urine examination: A urine examination is sometimes recommended to confirm the legionella infection, although it may not be recommended in all the cases. There is a specific test known as the legionella urinary antigen test, which is used to detect a specific protein that is a component of the legionella bacteria. These proteins can be traced in the urine samples even months after having been treated for the disease.
- Spinal tap fluid testing: In severe cases, medical practitioners may recommend testing of the spinal fluid that is done by performing a lumbar puncture in the spine. The fluid tested is known as cerebrospinal fluid or CSF, and it surrounds the spine. It is removed from the lower region of the back through a needle. A local anesthesia is administered to make the area numb before the fluid is removed. This fluid testing helps to diagnose if the legionella bacteria has affected the brain. The bacteria could infect the brain causing a condition known as legionella meningitis. This test is not recommended for all patients, but only in cases in which the doctor suspects symptoms of meningitis.
The best way to prevent Legionnaires' disease from creating complications is timely medical intervention before the infection spreads to the other parts of the body. Recovery from the disease depends upon the severity of the infection and varies from person to person. In some cases, patients may require hospitalization to recover from the infection.