''Mycoplasma'' pneumonia (also known as "walking pneumonia") is a form of

bacterial pneumonia Bacterial pneumonia is a type of pneumonia caused by bacterial infection. Types Gram-positive ''Streptococcus pneumoniae'' () is the most common bacterial cause of pneumonia in all age groups except newborn infants. ''Streptococcus pneumoniae'' ...

caused by the bacterial species ''

Mycoplasma pneumoniae ''Mycoplasma pneumoniae'' is a very small bacterium in the class Mollicutes. It is a human pathogen that causes the disease mycoplasma pneumonia, a form of atypical bacterial pneumonia related to cold agglutinin disease. ''M. pneumoniae'' is char ...

''. It is also known as PPLO, which is an acronym for Pleuro Pneumonia Like Organism.

Pathophysiology

''Mycoplasma pneumoniae'' is spread through

respiratory droplet transmission A respiratory droplet is a small aqueous droplet produced by exhalation, consisting of saliva or mucus and other matter derived from respiratory tract surfaces. Respiratory droplets are produced naturally as a result of breathing, speaking, sn ...

. Once attached to the mucosa of a host organism, ''M. pneumoniae'' extracts nutrients, grows, and reproduces by

binary fission Binary may refer to: Science and technology Mathematics * Binary number, a representation of numbers using only two digits (0 and 1) * Binary function, a function that takes two arguments * Binary operation, a mathematical operation that t ...

. Attachment sites include the upper and lower respiratory tract, causing

pharyngitis Pharyngitis is inflammation of the back of the throat, known as the pharynx. It typically results in a sore throat and fever. Other symptoms may include a runny nose, cough, headache, difficulty swallowing, swollen lymph nodes, and a hoarse voice ...

bronchitis Bronchitis is inflammation of the bronchi (large and medium-sized airways) in the lungs that causes coughing. Bronchitis usually begins as an infection in the nose, ears, throat, or sinuses. The infection then makes its way down to the bronchi. ...

, and

pneumonia Pneumonia is an inflammatory condition of the lung primarily affecting the small air sacs known as alveoli. Symptoms typically include some combination of productive or dry cough, chest pain, fever, and difficulty breathing. The severity ...

. The infection caused by this bacterium is called

atypical pneumonia Atypical pneumonia, also known as walking pneumonia, is any type of pneumonia not caused by one of the pathogens most commonly associated with the disease. Its clinical presentation contrasts to that of "typical" pneumonia. A variety of microorgan ...

because of its protracted course and lack of sputum production and wealth of extrapulmonary symptoms. Chronic ''Mycoplasma'' infections have been implicated in the pathogenesis of

rheumatoid arthritis Rheumatoid arthritis (RA) is a long-term autoimmune disorder that primarily affects joints. It typically results in warm, swollen, and painful joints. Pain and stiffness often worsen following rest. Most commonly, the wrist and hands are involv ...

and other rheumatological diseases. ''Mycoplasma'' atypical pneumonia can be complicated by

Stevens–Johnson syndrome Stevens–Johnson syndrome (SJS) is a type of severe skin reaction. Together with toxic epidermal necrolysis (TEN) and Stevens–Johnson/toxic epidermal necrolysis (SJS/TEN), it forms a spectrum of disease, with SJS being less severe. Erythema ...

autoimmune hemolytic anemia Autoimmune hemolytic anemia (AIHA) occurs when antibodies directed against the person's own red blood cells (RBCs) cause them to burst (lyse), leading to an insufficient number of oxygen-carrying red blood cells in the circulation. The lifetime of ...

, cardiovascular diseases,

encephalitis Encephalitis is inflammation of the brain. The severity can be variable with symptoms including reduction or alteration in consciousness, headache, fever, confusion, a stiff neck, and vomiting. Complications may include seizures, hallucinations, ...

, or

Guillain–Barré syndrome Guillain–Barré syndrome (GBS) is a rapid-onset muscle weakness caused by the immune system damaging the peripheral nervous system. Typically, both sides of the body are involved, and the initial symptoms are changes in sensation or pain often ...

Diagnosis

''M. pneumoniae'' infections can be differentiated from other types of pneumonia by the relatively slow progression of symptoms. A positive blood test for cold-hemagglutinins in 50–70% of patients after 10 days of infection (

cold-hemagglutinin-test Cold agglutinin disease (CAD) is a rare autoimmune disease characterized by the presence of high concentrations of circulating cold sensitive antibodies, usually IgM and autoantibodies that are also active at temperatures below , directed again ...

should be used with caution or not at all, since 50% of the tests are false-positive), lack of bacteria in a Gram-stained sputum sample, and a lack of growth on blood agar. PCR has also been used.

Treatment

While antibiotics with activity specifically against ''M. pneumoniae'' are often used (e.g.,

erythromycin Erythromycin is an antibiotic used for the treatment of a number of bacterial infections. This includes respiratory tract infections, skin infections, chlamydia infections, pelvic inflammatory disease, and syphilis. It may also be used duri ...

doxycycline Doxycycline is a broad-spectrum tetracycline class antibiotic used in the treatment of infections caused by bacteria and certain parasites. It is used to treat bacterial pneumonia, acne, chlamydia infections, Lyme disease, cholera, typhus, an ...

), it is unclear if these result in greater benefit than using antibiotics without specific activity against this organism in those with an infection acquired in the community.

References

External links

{{Respiratory pathology Pneumonia Bacterial diseases

Pathophysiology

Diagnosis

Treatment

See also

References

External links