WASHINGTON — Consider the diagnosis of legionnaires' disease in any child with pneumonia who doesn't respond to β-lactam antibiotic therapy, Dr. David Greenberg and his associates advised in a poster presented at the annual Interscience Conference on Antimicrobial Agents and Chemotherapy.
Legionnaires' disease is considered a rare cause of community-acquired pneumonia in children. Most of the published literature on the subject is in the form of case reports, and nearly all have used serologic tests, for which sensitivity and specificity are uncertain. Awareness of Legionella as a potential cause of pediatric pneumonia is important because the disease doesn't respond to standard empiric therapy and may be quite severe and life-threatening, said Dr. Greenberg of Soroka University Medical Center, Beer-Sheva, Israel.
A Medline search identified 76 reported cases of legionnaires' disease in children. Of those, 33 (43%) came from the United States, possibly because of a higher index of suspicion for the disease among U.S. physicians and the availability of specific diagnostic tests for Legionella. Spain was second, with 10 cases, followed by Italy with 7. Another 13 countries reported five or fewer cases each. None were reported from developing countries, probably because diagnostic tests are not available there, the investigators noted at the meeting, sponsored by the American Society for Microbiology.
Patients ranged in age from 5 days to 19 years, with a mean of 24 months.
Symptoms and signs were nonspecific, including fever in nearly all the patients. Cough, tachypnea, and hypoxia also were common.
Results of laboratory tests also were nonspecific and not helpful in making the diagnosis.
Of 63 patients with chest radiographs, pulmonary infiltrates were seen in 97% and pleural effusion in 30%.
Forty-one (54%) of the 76 cases were classified as hospital-acquired. These patients were more likely to be newborns and to have underlying diseases. The 35 patients with community-acquired legionnaires' disease were less likely to be immunosuppressed (37% vs. 90%).
Mortality was 41% in the hospital-acquired cases and 23% in the community-acquired cases. Compared with the 51 who survived, the 25 who died were younger and were more likely to have underlying diseases. Children who received inappropriate antibiotics were three times more likely to die than were those appropriately treated (76% vs. 24%), Dr. Greenberg and his associates said.
Environmental links to Legionella were identified in 23 (88%) of the hospital-acquired cases, compared with just 3 (33%) of those acquired in the community. Tap water, hot water tanks, showerheads, respiratory therapy equipment, and humidifiers were the most common sites of colonization. These findings suggest that all hospitals—including children's hospitals—should routinely culture their water supply for Legionella, they advised.