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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, p. 417] 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. 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] Erythema multiforme is fairly common, especially in children with Mycoplasma pneumonia. [UpToDate Online 12.2] The organism is not usually visible in sputum Gram stains. 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. About 3/4 of patients develop bronchitis while only about 1/3 of patients develop pneumonia. [Lexi-ID, p. 226-9] 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. 2271-8] EPIDEMIOLOGY: Outbreaks occur in institutions and military populations especially in the late summer and fall. [CCDM, p. 417-9] Incidence does not vary much with season, but relative to other respiratory infections, it is more common in the late summer and fall. [5MCC] |