Mycoplasmal pneumonia


Infection, Occupational




Primary atypical pneumonia; Mycoplasma pneumoniae infection

Biomedical References

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Common findings are gradual onset of pharyngitis, headache, paroxysmal cough, pleuritic chest pain, dry cough (and later productive cough), infiltrates, and leukocytosis. [CCDM]

Most patients do not develop pneumonia, but have cough, wheezing, dyspnea, pharyngitis (6-59%), rhinorrhea (2-40%), and bullous myringitis (2-35%). [Cohen, p. 175] Fever is usually in the 101-103 range. 3/4 of patients have rales and rhonchi. Each of the following is present in about 1/4 to 1/2 of patients: runny nose, myalgias, chest pain, sore throat, and hoarseness. About 1/4 of patients have leukocytosis. About 1/4 of adults with pneumonia have pleural effusions. Blood-tinged sputum is rarely seen. [ID, p. 504-7, 1366] About 23% of community-acquired pneumonia is caused by Mycoplasma. Cases of upper respiratory tract infection are about 20 times more common than cases of pneumonia. [Harrison, p. 680]

CNS complications occur in about 1/1000 cases (meningoencephalitis, cranial nerve neuritis, neuropathy, and Guillain-Barre syndrome). Other rare complications are erythema nodosum, pericarditis, nephritis, Stevens-Johnson syndrome, and aplastic or hemolytic anemia. [ID, p. 504-7, 1366] A variety of skin eruptions are associated with mycoplasma pneumonia (macular, vesicular, and urticarial). Bullous myringitis and arthritis are rare. Pharyngitis may occur, but without the prominent cervical adenopathy seen in streptococcal sore throat. Arthralgias are common. Neurological complications have been reported, but not proven to be causally related. [PPID, p. 2481-9]

75% of patients may have cold agglutinin antibodies and a positive Coombs' test, but "clinically significant autoimmune hemolytic anemia is uncommon." [PPID, p. 287] Cold agglutinins develop in 50-75% of patients 1-2 weeks after infection; hemolysis may be severe, but it is not usually clinically significant. [Cohen, p. 1803]

The infection tends to spread in families in a slow step-wise manner with a 2-3 week delay between family members. The highest attack rates occur in children and young adults 5-20 years of age. [Cecil, p. 1912] Outbreaks occur in institutions and military populations especially in the late summer and fall. [CCDM, p. 476-8] Incidence does not vary much with season, but causes a greater percentage of pneumonia in summer and fall. [5MCC-2014]


6 days to 1 month; usually about 2 weeks;


Requires 7-14 days to grow in culture; Cold agglutinin titer > 1:32 supportive but not specific; About 89-95% sens/spec to detect DNA in sputum by GenProbe or PCR; IgM (-) for first 7-10 days; [ABX Guide]

ICD-9 Code


Effective Antimicrobics


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