(See also Overview of Pneumonia Overview of Pneumonia Pneumonia is acute inflammation of the lungs caused by infection. Initial diagnosis is usually based on chest x-ray and clinical findings. Causes, symptoms, treatment, preventive measures, and... read more in adults and Overview of Neonatal Infections Overview of Neonatal Infections Neonatal infection can be acquired In utero transplacentally or through ruptured membranes In the birth canal during delivery (intrapartum) From external sources after birth (postpartum) Common... read more .)
Pneumonia is the most common invasive bacterial infection after primary sepsis. Early-onset pneumonia is part of generalized sepsis that first manifests at or within hours of birth (see Neonatal Sepsis Neonatal Sepsis Neonatal sepsis is invasive infection, usually bacterial, occurring during the neonatal period. Signs are multiple, nonspecific, and include diminished spontaneous activity, less vigorous sucking... read more ). Late-onset pneumonia usually occurs after 7 days of age, most commonly in neonatal intensive care units among infants who require prolonged endotracheal intubation because of lung disease (called ventilator-associated pneumonia).
Etiology of Neonatal Pneumonia
Organisms are acquired from the maternal genital tract or the nursery. These organisms include gram-positive cocci (eg, groups A and B streptococci Streptococcal Infections Streptococci are gram-positive aerobic organisms that cause many disorders, including pharyngitis, pneumonia, wound and skin infections, sepsis, and endocarditis. Symptoms vary with the organ... read more , both methicillin-sensitive and methicillin-resistant Staphylococcus aureus Staphylococcal Infections Staphylococci are gram-positive aerobic organisms. Staphylococcus aureus is the most pathogenic; it typically causes skin infections and sometimes pneumonia, endocarditis, and osteomyelitis... read more ) and gram-negative bacilli (eg, Escherichia coli Escherichia coli Infections The gram-negative bacterium Escherichia coli is the most numerous aerobic commensal inhabitant of the large intestine. Certain strains cause diarrhea, and all can cause infection when they invade... read more , Klebsiella Klebsiella, Enterobacter, and Serratia Infections The gram-negative bacteria Klebsiella, Enterobacter, and Serratia are closely related normal intestinal flora that rarely cause disease in normal hosts. Diagnosis is by culture. Treatment is... read more species, Proteus Proteeae Infections The Proteeae are normal fecal flora that often cause infection in patients whose normal flora have been disturbed by antibiotic therapy. The Proteeae constitute at least 3 genera of gram-negative... read more species). In infants who have received broad-spectrum antibiotics, many other pathogens may be found, including Pseudomonas Pseudomonas and Related Infections Pseudomonas aeruginosa and other members of this group of gram-negative bacilli are opportunistic pathogens that frequently cause hospital-acquired infections, particularly in ventilator patients... read more , Citrobacter, Bacillus, and Serratia Klebsiella, Enterobacter, and Serratia Infections The gram-negative bacteria Klebsiella, Enterobacter, and Serratia are closely related normal intestinal flora that rarely cause disease in normal hosts. Diagnosis is by culture. Treatment is... read more . Viruses or fungi cause some cases.
Symptoms and Signs of Neonatal Pneumonia
Late-onset hospital-acquired pneumonia manifests with unexplained worsening of the patient's respiratory status and increased quantities and a change in the quality of the respiratory secretions (eg, thick and brown). Infants may be acutely ill, with temperature instability and neutropenia.
Diagnosis of Neonatal Pneumonia
Evaluation includes chest x-ray, pulse oximetry, blood cultures, and Gram stain and culture of tracheal aspirate.
New, persistent infiltrates should be visible on chest x-ray but may be difficult to recognize if the infant has severe bronchopulmonary dysplasia Bronchopulmonary Dysplasia (BPD) Bronchopulmonary dysplasia is chronic lung disease of the neonate that typically is caused by prolonged ventilation and is further defined by age of prematurity and extent of supplemental oxygen... read more .
If Gram stain of tracheal aspirate shows a significant number of polymorphonuclear leukocytes and a single organism that is consistent with the one that grows from culture of the tracheal aspirate, the likelihood increases that this organism is the cause of the pneumonia. Because bacterial pneumonia in neonates may disseminate, a full evaluation for sepsis Diagnosis Neonatal sepsis is invasive infection, usually bacterial, occurring during the neonatal period. Signs are multiple, nonspecific, and include diminished spontaneous activity, less vigorous sucking... read more , including a lumbar puncture, should also be done. However, blood cultures are positive in only 2 to 5% of cases of hospital-acquired pneumonia.
Treatment of Neonatal Pneumonia
Usually vancomycin and a broad-spectrum beta-lactam drug
Antimicrobial therapy in early-onset disease is similar to that for neonatal sepsis. Vancomycin (see table Vancomycin Dosage for Neonates ) and a broad-spectrum beta-lactam drug such as meropenem, piperacillin/tazobactam, or cefepime (see Table: Recommended Dosages of Selected Parenteral Antibiotics for Neonates Recommended Dosages of Selected Parenteral Antibiotics for Neonates In neonates, the extracellular fluid (ECF) constitutes up to 45% of total body weight, requiring relatively larger doses of certain antibiotics (eg, aminoglycosides) compared with adults. Lower... read more ) are the initial treatment of choice for most late-onset hospital-acquired pneumonia. This regimen treats sepsis as well as pneumonia with typical hospital-acquired pathogens including P. aeruginosa. Local patterns of infection and bacterial resistance should always be used to help guide empiric choices of antimicrobials. More specific antibiotics are substituted after sensitivity results are available. General treatment is the same as that for neonatal sepsis Treatment Neonatal sepsis is invasive infection, usually bacterial, occurring during the neonatal period. Signs are multiple, nonspecific, and include diminished spontaneous activity, less vigorous sucking... read more .
Exposure to chlamydial organisms during delivery may result in development of chlamydial pneumonia at 2 to 18 weeks. Infants are tachypneic but usually not critically ill and may also have a history of conjunctivitis Neonatal Conjunctivitis Neonatal conjunctivitis is watery or purulent ocular drainage due to a chemical irritant or a pathogenic organism. Prevention with antigonococcal topical treatment at birth is routine. Diagnosis... read more caused by the same organism. Eosinophilia may be present, and x-rays show bilateral interstitial infiltrates with hyperinflation.
Treatment of Chlamydial Pneumonia
Erythromycin or azithromycin
Treatment with erythromycin 12.5 mg/kg orally every 6 hours for 14 days or azithromycin 20 mg/kg orally/IV once a day for 3 days typically resolves the pneumonia. Occasionally, however, a second course may be necessary (see Table: Recommended Dosages of Selected Oral Antibiotics for Neonates* Recommended Dosages of Selected Oral Antibiotics for Neonates* In neonates, the extracellular fluid (ECF) constitutes up to 45% of total body weight, requiring relatively larger doses of certain antibiotics (eg, aminoglycosides) compared with adults. Lower... read more ). Because erythromycins in neonates may cause hypertrophic pyloric stenosis Hypertrophic Pyloric Stenosis Hypertrophic pyloric stenosis is obstruction of the pyloric lumen due to pyloric muscular hypertrophy. Diagnosis is by abdominal ultrasonography. Treatment is surgical. Hypertrophic pyloric... read more (HPS), all neonates treated with erythromycin or azithromycin should be monitored for symptoms and signs of HPS and their parents should be counseled regarding potential risks.
The diagnosis of pneumonia secondary to Chlamydia trachomatis should prompt an evaluation of the mother and her partner because untreated maternal chlamydial infection may have complications such as pelvic inflammatory disease and sterility.