Mycoplasma disease and acute chest syndrome in sickle cell disease.
BACKGROUND
Acute chest syndrome (ACS) is the leading cause of hospitalization, morbidity, and mortality in patients with sickle cell disease. Radiographic and clinical findings in ACS resemble pneumonia; however, etiologies other than infectious pathogens have been implicated, including pulmonary fat embolism (PFE) and infarction of segments of the pulmonary vasculature. The National Acute Chest Syndrome Study Group was designed to identify the etiologic agents and clinical outcomes associated with this syndrome.


METHODS
Data were analyzed from the prospective study of 671 episodes of ACS in 538 patients with sickle cell anemia. ACS was defined as a new pulmonary infiltrate involving at least 1 complete segment of the lung, excluding atelectasis. In addition, the patients had to have chest pain, fever >38.5C, tachypnea, wheezing, or cough. Samples of blood and deep sputum were analyzed for evidence of bacteria, viruses, and PFE. Mycoplasma pneumoniae infection was determined by analysis of paired serologies. Detailed information on patient characteristics, presenting signs and symptoms, treatment, and clinical outcome were collected.


RESULTS
Fifty-one (9%) of 598 episodes of ACS had serologic evidence of M pneumoniae infection. Twelve percent of the 112 episodes of ACS occurring in patients younger than 5 years were associated with M pneumoniae infection. At the time of diagnosis, 98% of all patients with M pneumoniae infection had fever, 78% had a cough, and 51% were tachypneic. More than 50% developed multilobar infiltrates and effusions, 82% were transfused, and 6% required assisted ventilation. The average hospital stay was 10 days. Evidence of PFE with M pneumoniae infection was seen in 5 (20%) of 25 patients with adequate deep respiratory samples for the PFE assay. M pneumoniae and Chlamydia pneumoniae was found in 16% of patients with diagnostic studies for C pneumoniae. Mycoplasma hominis was cultured in 10 (2%) of 555 episodes of ACS and occurred more frequently in older patients, but the presenting symptoms and clinical course was similar to those with M pneumoniae.


CONCLUSIONS
M pneumoniae is commonly associated with the ACS in patients with sickle cell anemia and occurs in very young children. M hominis should be considered in the differential diagnosis of ACS. Aggressive treatment with broad-spectrum antibiotics, including 1 from the macrolide class, is recommended for all patients as well as bronchodilator therapy, early transfusion, and respiratory support when clinically indicated.
Neumayr
Lynne
L
Hematology/Oncology Department, Children's Hospital Oakland, Oakland, California 94609, USA. lneumayr@mail.cho.org
Lennette
Evelyne
E
Kelly
Dana
D
Earles
Ann
A
Embury
Stephen
S
Groncy
Paula
P
Grossi
Mauro
M
Grover
Ranjeet
R
McMahon
Lillian
L
Swerdlow
Paul
P
Waldron
Peter
P
Vichinsky
Elliott
E
D000208:Acute Disease; D000293:Adolescent; D000328:Adult; D000755:Anemia, Sickle Cell / Q000150:complications*; D016470:Bacteremia / Q000150:complications / Q000382:microbiology; D002637:Chest Pain / Q000453:epidemiology / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D023521:Chlamydophila Infections / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology; D016993:Chlamydophila pneumoniae / Q000302:isolation & purification; D005260:Female; D005334:Fever / Q000209:etiology; D006801:Humans; D007223:Infant; D008297:Male; D008875:Middle Aged; D009175:Mycoplasma Infections / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology; D019535:Mycoplasma hominis / Q000302:isolation & purification; D009177:Mycoplasma pneumoniae / Q000302:isolation & purification; D018410:Pneumonia, Bacterial / Q000150:complications / Q000175:diagnosis / Q000453:epidemiology / Q000382:microbiology; D011019:Pneumonia, Mycoplasma / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology; D011446:Prospective Studies; D012120:Respiration Disorders / Q000453:epidemiology / Q000209:etiology*; D016036:Seroepidemiologic Studies; D013577:Syndrome; D016896:Treatment Outcome