Mycoplasma pneumonia tends to spread in families in a slow step-wise manner with a 2-3 week delay between family members. Most patients do not develop pneumonia, but have cough, wheezing, dyspnea, pharyngitis (6-59%), and rhinorrhea (2-40%).
CASES/YEAR
30,000,000 (US); 600,000,000 (Global)
OTHER NAMES
Primary atypical pneumonia; Mycoplasma pneumoniae infection;
INCUBATION
6-32 days; [CCDM, p. 470]
INITIAL SYMPTOMS
Common findings are gradual onset of pharyngitis, headache, paroxysmal cough, pleuritic chest pain, dry cough (and later productive cough), infiltrates, and leukocytosis. [CCDM, p. 469]
PRECAUTIONS
"Respiratory secretions may be infectious. Hand hygiene and cough etiquette." [CCDM, p. 471]
COMMENTS
FINDINGS:
Most patients do not develop pneumonia, but have cough, wheezing, dyspnea, pharyngitis (6-59%), and rhinorrhea (2-40%). [Cohen, 3rd Ed, p. 1803] 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. About 17% of patients had a rash (maculopapular, vesicular, petechial, or urticarial) in some case series. If anemia occurs, it is usually in the second or third week. [Harrison ID, p. 699-700]
COMPLICATIONS:
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 (maculopapular, vesicular, and urticarial). Rhinitis, pharyngitis, and otitis media may occur. Arthralgias are common. Neurological complications (meningoencephalitis, myelitis, and stroke) occur in up to 7% of hospitalized patients. [PPID, p. 2335-7]
LABORATORY:
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, 3rd Ed, p. 1803] The organism has no cell wall and is not visible by Gram stain. [Harrison ID, p. 700]
EPIDEMIOLOGY:
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. 1972] Outbreaks occur in institutions and military populations especially in the late summer and fall. [CCDM, p. 470]
DIAGNOSTIC
"Nucleic acid amplification (NAATs, GenProbe or PCR on sputum): ~89-95% sensitivity/specificity compared to traditional culture/serology." [ABX Guide] PCR & paired sera recommended; [Harrison ID, p. 701]
SIGNS & SYMPTOMS
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>arthralgia
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>fatigue, weakness
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>fever
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>fever, biphasic or relapsing
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>myalgia
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>relative bradycardia
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E pharyngitis
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E rhinitis
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H anemia
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H hemolysis
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H leukocytosis
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H lymphadenopathy
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N confusion, delirium
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N headache
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R chest pain
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R cough
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R dyspnea
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R hemoptysis
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R sputum production
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R wheezing
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S papules or plaques
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S petechiae and ecchymoses
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S rash (exanthem)
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S skin blister or vesicles
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S urticaria
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X lung infiltrates
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X pleural effusions
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*acute renal failure
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*ARDS
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*arthritis
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*bleeding tendency
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*cranial neuropathy
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*encephalitis
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*erythema nodosum
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*glomerulonephritis
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*hepatitis
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*meningitis
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*myelitis
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*myocarditis
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*pancreatitis
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*paralysis
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*pericarditis
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*peripheral neuropathy
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*pneumonia
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*rhabdomyolysis
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*stupor, coma
ENTRY
Inhalation, Skin or Mucous Membranes (Includes Conjunctiva)
RISK FACTORS
- Care for patients (droplet/airborne)
- Live together in close quarters
REFERENCES FOR CASES/YEAR
1. (US) More than 2 million cases of pneumonia per year; Respiratory infections may be 20 million to 40 million per year; [Cecil, p. 1972[ A study in 1995 found M. pneumoniae caused 23% of pneumonia cases in 6207 ambulatory and hospitalized adults; [Harrison ID, p. 700] Estimate 30 million cases per year;
2. (Global) A study in 1995 found M. pneumoniae caused 23% of pneumonia cases in 6207 ambulatory and hospitalized adults; [Harrison ID, p. 700] Estimate 20 X US rate = 600 million cases per year;