Further Outpatient Care
With appropriate treatment, uncomplicated episodes of M pneumoniae infection can be expected to resolve clinically within 7-10 days after onset.
Additional laboratory tests or radiographs usually are not necessary unless the illness fails to respond to therapy, which would raise questions about the accuracy of the microbiologic diagnosis or the possibility of chronic infection, which sometimes occurs.
The presence of extrapulmonary manifestations may warrant further workup and follow-up, depending on their nature and severity.
Improvement of pneumonia on chest radiographs may lag behind clinical improvement.
Deterrence/Prevention
Antimicrobial prophylaxis
As with other bacterial infections, researchers have studied the value of antimicrobial prophylaxis for those in contact with persons with M pneumoniae infection.
Klausner et al (1998) reported that the administration of oral azithromycin plus standard epidemic control measures significantly reduced secondary attack rates following an outbreak of M pneumoniae pneumonia in a long-term care facility for mentally and developmentally disabled persons. [28]
Previous studies using tetracyclines also demonstrated the efficacy of chemoprophylaxis in reducing transmission of M pneumoniae pneumonia.
Vaccines
Researchers have studied vaccines for many years, but they have not produced a vaccine for general use.
The fact that natural infection does not confer complete protective immunity against future infections makes this approach less promising.
Isolation
Because of the endemicity of infection with M pneumoniae in susceptible populations, isolating patients is seldom practical and generally is not recommended.
Complications
Extrapulmonary complications
Extrapulmonary complications may occur simultaneously with the onset of respiratory manifestations or as long as several days later. These complications may predominate to the extent that physicians may overlook a primary respiratory tract infection. Less than 10% of cases of M pneumoniae infections are associated with nonrespiratory illnesses, with the exception of various skin rashes, nausea, vomiting, and diarrhea, which may occur more often. [15]
When extrapulmonary manifestations occur, however, they clearly can complicate the diagnosis and the recovery; they also make hospitalization more likely. Thus, a careful history and physical examination are essential, and follow-up is indicated.
Researchers believe that an autoimmune response plays a role in some extrapulmonary complications, but, because M pneumoniae has been been detected by culture and/or PCR directly from cerebrospinal, pericardial, and synovial fluids and from other extrapulmonary sites, always consider direct invasion by this organism and order appropriate diagnostic testing for confirmation.
Extrapulmonary manifestations may include the following:
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Meningoencephalitis
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Ascending (ie, Guillain-Barré) paralysis
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Transverse myelitis
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Myopericarditis
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Cardiac arrhythmia
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Raynaud phenomenon
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Hemolytic anemia
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Disseminated intravascular coagulation
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Renal failure
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Arthritis
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Erythema multiforme (ie, Stevens-Johnson syndrome)
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Erythema nodosum
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Urticaria
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Ulcerative stomatitis
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Nausea
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Vomiting
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Diarrhea
Prognosis
Most persons who are free of underlying conditions that may adversely affect the outcome of a respiratory tract infection can expect an excellent prognosis and a full return of pulmonary function.
For the minority of patients who have severe disease, diminished lung function may persist for weeks to months.
For the few persons who experience disseminated extrapulmonary symptoms, particularly neurologic manifestations, recovery can require weeks to months. While most recover fully and uneventfully, some persons with neurologic manifestations may experience long-term paralysis, and reports describe cases of permanent neurologic deficits.
