What is Mycoplasma Pneumonia?
Mycoplasma pneumonia is a type of bacteria that can cause infections in people. Commonly, it leads to infections in the upper respiratory tract or the passages and organs involved in breathing. However, it can also cause pneumonia, a type of lung infection. In fact, it’s one of the top causes of a less common form of pneumonia, known as “atypical pneumonia,” in the United States. Some people also believe that Mycoplasma pneumonia can cause infections in parts of the body outside the lungs. However, more evidence is needed to confirm this. This bacterial infection was first identified by a researcher named Reimann, who studied seven patients with severe overall symptoms. He called the disease “primary atypical pneumonia.”
What Causes Mycoplasma Pneumonia?
Mycoplasma are the smallest organisms that can live independently in the natural world. More than 120 different types of Mycoplasma exist, but only 13 have been found in humans, and only four are known to cause disease in humans. Among those four, Mycoplasma pneumoniae is the one most likely to cause disease.
Mycoplasma pneumoniae is a tiny, rod-shaped organism. It lacks a cell wall, which means it can’t be seen using a common lab test called a Gram stain. Growing it in a lab requires special conditions and a serum-supplemented medium (a substance to support its growth). But because it’s very demanding in its needs and takes a long time to grow, it’s not usually cultured, or grown in a lab.
People with an infection can continue to release Mycoplasma pneumoniae from their respiratory tract for weeks after the initial infection has occurred. However, finding the organism doesn’t necessarily mean that the infection is still ongoing, since it can be detected even after the acute phase of the infection is over.
Risk Factors and Frequency for Mycoplasma Pneumonia
Mycoplasma pneumoniae is often the cause of pneumonia that people catch in their everyday life. It spreads via tiny droplets when people are close to each other. It typically takes about 2 to 3 weeks for symptoms to appear after you’ve been exposed to the bacteria. This type of infection is most common during the winter, but it can happen anytime during the year.
About 1% of the US population gets infected with M pneumoniae every year. However, the actual number may be higher, as some infections are symptom-free or cause only mild illness that doesn’t require a hospital stay. Outbreaks of this infection are common in places where people live close together like military bases, hospitals, nursing homes, and other care facilities.
Not everyone who catches M pneumoniae gets sick with pneumonia, in fact, only 5 to 10% do. It can cause infections in the upper and lower respiratory tracts in people of all ages.
Signs and Symptoms of Mycoplasma Pneumonia
Mycoplasma pneumoniae infections, also known as walking pneumonia, often have no symptoms. Symptoms that do occur are usually worse than what doctors can see during a physical examination. The infection typically develops slowly and can start with headaches, general discomfort, and a low fever. A persistent cough is usually the main symptom related to the lungs, and chest pain from all the coughing is common. Wheezing, throat pain, runny nose, and ear pain may also occur. About 15% to 20% of people who get pneumonia may also have fluid build-up around their lungs, which can lead to more health concerns. Most cases of walking pneumonia are mild and will get better on their own. However, sometimes they can become severe. Other signs that could indicate this kind of infection include breaking down of red blood cells, skin rashes, joint pain, gastrointestinal issues, and heart problems, although these are quite rare.
A physical examination usually doesn’t show many signs of the infection. During a listening check of the chest with a stethoscope, everything might sound normal even if pneumonia is present. Crackling and wheezing sounds may become noticeable later. Tenderness of the sinuses and slight redness at the back of the throat may also occur. There may also be a mild red and bumpy or blistery rash. In some cases, blisters might appear on the eardrum.
- Headaches
- General discomfort
- Low fever
- Persistent cough
- Chest pain from coughing
- Wheezing
- Throat pain
- Runny nose
- Ear pain
- Fluid around the lungs (in some cases)
- Breakdown of red blood cells, skin rashes, joint pain, gastrointestinal issues, and heart problems (rare)
Testing for Mycoplasma Pneumonia
Mycoplasma pneumonia, a type of lung infection, can be challenging to tell apart from other types of atypical pneumonia based on clinical symptoms or imaging scans alone. The disease usually begins slowly, affecting multiple systems in the body, but does not typically cause an increase in white blood cells count.
Most people with this condition seek care as outpatients. Doctors often treat community-acquired pneumonia without conducting detailed microbial tests because typical treatments usually work well. If available, a test called PCR is the top choice because it can be done quickly.
Sometimes, testing for something called cold agglutinins can support a diagnosis when a fast result is needed. Since mycoplasma pneumonia doesn’t have a cell wall and is sensitive to its environment, traditional methods of staining and culturing it for testing aren’t helpful.
Instead, this bacteria needs a special environment to grow, and it can take between 7 to 21 days for that to happen. Blood tests called serologic tests like complement fixation, enzyme-linked immunoassay, immunochromatography, and hemagglutination can be used. These tests are considered reliable if they show a significant increase or decrease in certain substances or a single level of more than 1:32, indicating the presence of mycoplasma pneumonia.
Most patients with pneumonia will have a process called hemolysis, that causes red blood cells to break down, and this typically results in a positive Coomb test and increased numbers of young red blood cells, known as reticulocytes. More than half of the patients with mycoplasma disease have higher cold agglutinin levels, but this isn’t exclusive to mycoplasma infections; people with viral pneumonia or infectious mononucleosis from the Epstein-Barr virus or cytomegalovirus may also have this.
Despite the infection, 75% to 90% of patients have normal white blood cell counts. The most common findings on a chest x-ray are patchy areas of lung tissue damage or a pattern of small nodules, which can be in one or both lungs, often more towards the bottom.
Patients with mycoplasma infection and asthma usually have higher levels of eosinophil cationic protein, a protein believed to damage the lining of the airways and cause an overreaction of the muscles that control the airways. However, more research is needed before it is accepted universally as a marker for diagnosing mycoplasma infection.
Treatment Options for Mycoplasma Pneumonia
When symptoms of pneumonia come on gradually, affect parts of the body outside the lungs, and are not associated with an increase in white blood cells, it could be a sign of atypical pneumonia. Often, people with this type of pneumonia, caused by the bacterium M. pneumoniae, will visit their local doctor or clinic for treatment. They might have been feeling ill for a while before they decide to seek medical help or before they start taking antibiotics.
Doctors often treat M. pneumoniae with a few different antibiotics, including those in the macrolide, doxycycline, or fluoroquinolone groups. Of these, azithromycin is used most frequently. While most forms of bacteria are responsive to these antibiotics, some are becoming resistant to the macrolide group. If a patient doesn’t respond to macrolide antibiotics, doctors can switch to a different type.
If you’ve been exposed to M. pneumoniae but haven’t developed pneumonia, your doctor usually doesn’t need to give you preventative antibiotics. However, preventative treatment might be recommended for those at risk of developing severe infections, like people with sickle cell disease or immune deficiencies. In these situations, the antibiotics doxycycline or macrolides are often used.
What else can Mycoplasma Pneumonia be?
Mycoplasma pneumoniae is a common cause of pneumonia, particularly in healthy individuals under the age of 40. It’s more frequently found during late summer and early autumn. It’s also more likely to affect people who live closely together, such as in prisons or military settings. The time between exposure to the bacteria and onset of illness, known as the incubation period, typically lasts between 14 to 21 days. Unlike other kinds of pneumonia, a noticeable symptom of mycoplasma pneumonia is the absence of a wet cough.
It’s important to note that there are other conditions which can show similar symptoms to mycoplasma pneumonia, and these should be ruled out during diagnosis. Here are some of them:
- Aspiration pneumonitis and pneumonia
- Bacterial pneumonia
- Chlamydia pneumoniae
- Coxiella burnetii infection
- Empyema
- Legionella pneumophila
- Lung abscess
- Pediatric pneumonia
- Q fever
- Viral pneumonia
What to expect with Mycoplasma Pneumonia
With timely treatment, most people with pneumonia fully recover and the prognosis is typically excellent. Symptoms of pneumonia like cough, fever, and difficulty breathing usually disappear within a few days. However, young children may experience more severe pneumonia, and people with sickle cell anemia, a blood disorder, could develop acute chest syndrome, a serious lung-related complication. Unfortunately, immunity to the bacteria that causes this type of pneumonia doesn’t last long, meaning you can get infected again.
Possible Complications When Diagnosed with Mycoplasma Pneumonia
Mycoplasma pneumonia is usually a harmless infection for most people, but it can cause complications, especially in children and elderly individuals. The possible complications can include:
- ARDS (A serious lung condition)
- Bronchiolitis obliterans (a lung disease that can obstruct small airways)
- Lobar consolidation (occurs when all or a substantial part of a lung lobe fills with fluids)
- Lung abscess (a pus-filled cavity in the lung)
- Necrotizing pneumonitis (a severe inflammatory condition of the lung)
- Pleural effusion (fluid buildup between the tissues that line the lungs and the chest) or empyema (puss in the pleural cavity)
- Respiratory failure
Complications can also occur outside of the lungs (extrapulmonary). These might be due to the bacteria itself or the immune response to it. The following non-lung related complications could include:
- Heart issues like abnormalities in heart rhythm, blocks in heart conduction, pericarditis (inflammation of the outer lining of the heart), or congestive heart failure, particularly in young people
- CNS issues (nervous system), including encephalitis (brain inflammation), transverse myelitis (spinal cord inflammation), aseptic meningitis (inflammation of the protective membranes covering the brain and spinal cord), and cerebellar ataxia (uncoordinated movements) are rare but more common in children
- Blood issues such as mild hemolytic anemia due to the immune response to M Pneumoniae which might affect red blood cells
- Skin conditions like urticaria (hives), erythema nodosum (red, painful lumps), or Steven Johnson syndrome can occur in around a third of patients with M Pneumoniae infection who also experience myalgia (muscle pain), arthralgia(joint pain), and in very rare cases, septic arthritis (infected joints)
- Gastrointestinal issues like pancreatitis (inflammation of the pancreas) or hepatitis might be related to the body’s immune response
- Eye issues like conjunctivitis (pink eye), optic papillitis (inflammation of the optic nerve at the point of entry into the eye), anterior uveitis (inflammation of the middle layer of the eye), and cranial neuropathies (damage or dysfunction of one or more cranial nerves)
- Kidney problems like glomerulonephritis (a type of kidney disease) due to immune responses are rare but can occur
Preventing Mycoplasma Pneumonia
It’s important for patients to understand how to prevent infections. This includes knowledge about important vaccinations, like the pneumococcal vaccine, which protects against some types of pneumonia, and the influenza vaccine, which not only helps to prevent the flu but can also help to prevent possible flu-related complications such as pneumonia.
If a patient smokes, they should be strongly encouraged and given support to quit as smoking can increase the risk of pneumonia and cause other health problems.
Addressing any underlying health conditions, such as asthma (a condition that affects the lungs), diabetes (a disorder that affects how your body uses blood sugar), or congestive heart failure (a condition where the heart doesn’t pump blood as well as it should), can also help prevent pneumonia. It’s vital to manage these conditions properly since they can weaken the immune system, making a person more susceptible to infections like pneumonia.
