Expert Q&A: Neonatal Pneumonia

Respiratory distress affects up to 7% of term neonates and represents one of the most common reasons for admission to the neonatal intensive care unit (NICU).¹ Among the term and late preterm infants admitted to the NICU, 15% and 29%, respectively, develop respiratory morbidity, with higher rates noted among those born <34 weeks gestation.¹ Given the associated risks, including respiratory failure and cardiopulmonary arrest, it is “imperative that any health care practitioner caring for newborn infants can readily recognize the signs and symptoms of respiratory distress, differentiate various causes, and initiate management strategies to prevent significant complications or death,” according to an article published in 2014 in Pediatrics in Review.¹

Pneumonia is one of the leading causes of neonatal respiratory distress and is most commonly acquired at birth. Risk factors include maternal infection, preterm birth, and rupture of membranes >18 hours before delivery.^1,2 “On the basis of strong evidence, prevention of neonatal pneumonia and its complications focuses on maternal [group B streptococcus (GBS)] screening, intrapartum antibiotic prophylaxis, and appropriate follow-up of newborns at high risk after delivery,” wrote the review authors.¹

As such, neonatal pneumonia demonstrates an important, high-stakes clinical scenario that highlights the necessity of cross-speciality cohesion. Group B streptococcal infection screening and management, in conjunction with ease in assessing appropriate antibiotic therapy of neonates and infants in the case of pneumonia, is as pivotal as identification of such an infection and comfort with management protocols. Care of infants with pneumonia by definition requires comfort in both infectious diseases and pulmonology.

For additional discussion and clinical guidance on the topic, Infectious Disease Advisor checked in with Lia Gravari, MD, neonatologist at Children’s Minnesota, St Paul, and Billie Lou Short, MD, professor of pediatrics at George Washington University School of Medicine and chief of the Division of Neonatology at Children’s National Hospital, Washington, DC.

Infectious Disease Advisor: How is pneumonia diagnosed in neonates, and what are some of the key diagnostic challenges in these cases?

Dr Gravari: The diagnosis of neonatal pneumonia is based on a combination of clinical, radiographic, and microbiologic findings. From a clinical standpoint, neonates with sudden onset of respiratory distress or other signs of illness, such as apnea, lethargy, poor feeding, tachycardia, or abdominal distention, should be evaluated for pneumonia, including a complete sepsis workup. However, the challenge is that these findings are not unique to pneumonia.

From a radiographic standpoint, you can expect to observe bilateral alveolar densities with air bronchograms, irregular patchy infiltrates, pleural effusions, or occasionally a normal pattern. Pneumonia caused by certain bacteria can be difficult to distinguish from respiratory distress syndrome (RDS) in preterm infants. The challenge is that this is a 1-view image, and not very specific.

From a microbiologic standpoint, blood cultures are the gold standard test to identify an organism. In infants who are intubated, Gram stain and culture of tracheal aspirates may help to identify the causative pathogen. If a viral (RSV, adenovirus) or other (ureaplasma) cause is suspected, specific studies should be obtained, including polymerase chain reaction and viral cultures. The challenge is that cultures of 1 mL blood may not be sensitive, or the trach culture might identify a colonization vs a true infection.

Dr Short: The first thing to know is the mother’s history during pregnancy and delivery. If there was concern for infections in the mother, especially predelivery, this will put the baby at risk for infections. The mother’s obstetrician can answer many questions regarding this risk. The mother is usually tested for GBS, and if positive, will need to receive antibiotics before delivery. This should be discussed with the obstetrician.

Babies born to mothers who are positive for GBS, but not treated, are at risk for infection/sepsis and will need to be followed after birth by a pediatrician and treated if signs of sepsis occur. Later, infants who show signs such as being lethargic, for example, not acting like they usually do and not taking feeds like they usually do, need to be worked up for possible sepsis and subsequent development of acute respiratory distress syndrome.

Infectious Disease Advisor: What is the recommended treatment approach in these cases, and what are some of the main treatment challenges?

Dr Gravari: Antibiotics for the specific isolated organism should be initiated for 5 to 10 days. The challenges here include antibiotic resistance and the antibiotic effects on the gut flora of an immunocompromised host. Alternatively, in cases of viral etiology, the challenges of supportive treatment via lengthy intravenous access are significant, as well as the comorbidities associated with such treatment.

Many of these infections are preventable, or can at least be reduced in number with good hand hygiene, line bundles, proactive maintenance of the respiratory equipment, and the palivizumab vaccine. Adopting a “closed” neonatal unit model during the months when respiratory infections in the community are high, educating parents and visitors as well as clinicians about the importance of “self-reporting” an illness, and staying away from our vulnerable patients, help as well.

Infections in infants can be devastating, potentially leading to developmental delays, pulmonary hypertension, longer hospital stays, the need for treatment with extracorporeal membrane oxygenation, loss of extremities, and death. As we are going into the respiratory illness season, it’s important to do our part to prevent any infections that we can.

Dr Short: Most infections are caused by bacteria and treated with antibiotics. Considering the possibility of antibiotic resistance, testing should be performed to ensure the correct antibiotic is provided for the infection. Many infants will develop breathing issues and need oxygen therapy, and some may need a breathing machine until the infection is under control. Some infants experience a spread of the infection into their spinal fluid and may develop meningitis, which requires a much longer course of antibiotics.

Infectious Disease Advisor: What are remaining research and educational needs pertaining to neonatal pneumonia?

Dr Gravari: I think empowering nurses, respiratory technicians, physicians, and all of our support staff to educate patients about ways to prevent infection is really important. We all have the power and responsibility to make a difference.

Some of the research focusing on preventing preterm birth and treating maternal infections that could lead to neonatal pneumonia (ureaplasma, chorioamnionitis) is at the forefront right now. Learning more aspects in the pathogenesis of the inflammatory response in the development of chronic lung disease is another big front to be breached.

Working diligently to decrease intubation and/or minimize the amount of time a neonate stays intubated by supporting noninvasive modes of ventilation should be a priority, as should educating parents about the importance of RSV vaccination.

Dr Short: There has been a lot of research in this area, which is why mothers are tested and treated for GBS bacteria before delivery. This has markedly reduced the risk for this infection.^2,3 Other infections are difficult because they usually come from skin contamination, and we all have that. But in some it gets into the blood or lungs and causes sepsis; this phenomenon is not fully understood.

The biggest area of research needs to be in the development of better antibiotics. There is basically no treatment for some sepsis causes because the bacteria have become resistant to all antibiotics: we are going back to the era before penicillin was developed. It’s a very scary time, and more money for research in this area needs to be put forward.

References

1. Reuter S, Moser C, Baack M. Respiratory distress in the newborn. Pediatr Rev. 2014;35(10):417–429.

2. Hermansen CL, Mahajan A. Newborn respiratory distress. Am Fam Physician. 2015;92(11):994-1002.

3. Centers for Disease Control and Prevention. About Group B strep. Fast facts. https://www.cdc.gov/groupbstrep/about/fast-facts.html. Reviewed June 25, 2019. Accessed October 4, 2019.