Legionnaires’ Disease – Diagnosis and Treatment

The bacterium that causes Legionnaires’ disease has been isolated and identified by epidemiologists as Legionella pneumophila. Oddly enough, this particular strain of bacteria can induce two forms of illness that both produce flulike symptoms early on, and medical practitioners still do not know why some victims develop the less severe ailment, Pontiac fever, which only generates a mild bodily response, while others succumb to the much more serious affliction of Legionnaires’ disease.

Current research suggests that certain people may simply have a built-in immunity to the more serious consequences of the invading bacterium, while others cannot fight off the deleterious effects of the infection. In addition, where Pontiac fever ends and Legionnaires’ disease begins is not well defined, so in some cases people suspected of having the former ailment might actually have a mild case of the latter and vise versa.

Pontiac Fever vs. Legionnaires’ Disease

Pontiac fever is a self-limited illness that does not affect the lungs. Its incubation period is two to four days after exposure and complete recovery usually occurs within one week after the onset of symptoms. It is not treatable with antibiotics and its victims usually only require over-the-counter pain relievers for fever and muscle aches. Hospitalization is uncommon and the fatality rate is near zero.

In contrast, Legionnaires’ disease is a grave pneumonia-type infection. Hospitalization is common and the fatality rate can be as high as fifteen to thirty percent. Age of patient and relative strength of an individual’s immune system are critical factors. So it is necessary to determine if the Legionella pneumophila is, indeed, present in anyone who has any of the following symptoms which tend to worsen during the first four to six days after their initial onset:

• Chest pain
• Cough that does not produce much sputum or mucus (dry cough)
• Loss of appetite
• Coughing up blood
• Diarrhea, nausea, vomiting, and abdominal pain
• Fever
• General discomfort, uneasiness, or ill feeling (malaise)
• Headache
• Joint pain
• Loss of energy
• Muscle aches and stiffness
• Problems with balance
• Shaking chills
• Shortness of breath

Diagnosing Legionnaires ’ Disease

Whenever Legionnaires’ disease is suspected, a physical exam, including a bronchoscopy and/or an X-ray of the chest, can determine that a lung infection (pneumonia) is present. However, pneumonia is common and there are many different bacteria and other types of infectious agents that can cause the illness. In order to diagnose Legionnaires’ disease, further tests are necessary.

The most useful laboratory test is the Legionella urinary antigen test. This technique uses a patient’s urine sample to detect identifiable proteins – Legionella antigens – created by the bacterium. It can identify the L. pneumophila serogroup 1, which accounts for 80 – 90 percent of all Legionnaires’ disease cases.

During the course of treatment, you are likely to receive respiratory testing. However, follow up tests are also important. The Pulmonary Function Test (PFT), which measures the ability to breathe in and out of the lungs, using a spirometer. The test is used to measure and determine if there has been any permanent respiratory damage.

Another important diagnostic test gathers respiratory secretions such as phlegm or sputum, lung tissue, blood cultures, and/or pleural fluid in order to identify the bacteria causing the pneumonia by growing it and isolating in the laboratory. In addition, other blood tests can look for a patient’s specific antibodies, which are proteins that a person’s immune system makes in order to battle infection. Finding the exact antibody in the blood known to fight the Legionella pneumophila proves that it is present.

In certain cases, where it is suspected that the Legionella bacterium might have infected the surface of the brain, causing Legionella meningitis, a spinal tap may be administered to withdraw and test the patient’s cerebrospinal fluid for presence of the bacterium.

Because all these tests complement one another, whenever Legionnaires’ disease is suspected, a positive result from each test will increase the probability of a confirmed diagnosis.

Treating Legionnaires’ Disease

If Legionnaires’ disease is suspected, and even before the results of any lab tests are returned, antimicrobial therapy to fight the infection should begin, as prompt antibiotic treatment can markedly reduce the fatality of the disease. The chances of a person’s survival depend on the strength of the patient’s lungs and immune system, and the extent of the bacteria within the lung tissue. Usually, antibiotics are given intravenously in a hospital setting.

There are three major classes of antibiotics that are effective in treating Legionnaires’ disease. These include the fluoroquinolones such as levofloxacin (Levaquin), and moxifloxacin (Avelox); the macrolides such as erythromycin, azithromyocin (Zithromax), and clarithromycin (Biaxin); and the tetracyclines including doxycycline (Vibramycin).

A new class of antibiotics (glycylcyclines) is also effective. The choice of antibiotic is often dependent on the patient’s clinical state, his or her tolerance to the medication, and the physician’s degree of certainty as to the diagnosis. In severe cases of Legionnaires’ disease that seem more resistant to a single antibiotic, a second drug called rifampin (Rifadin) may be added.

Antibiotic treatment should last from one to three weeks, depending on a person’s physical condition and general state of health. Because pneumonia inflames the lungs and makes them work less well, oxygen therapy is commonly recommended, as well, as it makes it easier for the lungs to do their job. IV fluids are often given to keep the patient hydrated.

If you or a family member is suffering from the symptoms of Legionnaires’ disease and want to speak to an attorney, contact us for a free consultation and case evaluation. You may be entitled to compensation.