Respiratory Infection in an Infant

Case study: You walk into your family practice clinic and see a post-it note on your schedule that your first appointment has been bumped for an infant whose parents called in last night and spoke with the cross-covering physician at your practice. The note says that the infant had a low-grade fever, cough, and wheezing. When you walk into the examination room, you see the child’s father holding his five month-old infant who is not lethargic. The baby appears fussy and intermittently coughs loudly. You can hear a slight expiratory wheeze. What do you do next?

Your next step is to perform a physical exam. On exam, the baby appears ill. He is febrile to 100.6 F and slightly tachycardic. His breath sounds are crackly and he has some expiratory wheezes in his lower lung fields. However, he is oxygenating well with a pulse ox reading of 99% and does not appear cyanotic or in distress. His ears and throat do not have any erythema, and there is no fluid behind his tympanic membranes suggestive of an ear infection. What do you ask his father?

You ask the child’s father for a history of the child’s symptoms. He reports that he picked up his sick child from daycare the previous day when the child’s teachers called him to say that the baby had a fever. By late evening, the baby developed a cough and then began wheezing in the wee hours of the morning. At that point, the child’s mother called the on-call physician for your practice and was told to go to the Emergency Room if the child was in respiratory distress or to come into clinic in the morning if it appeared that the child was breathing well and not getting overly tired. No one else in the family is sick, including a school-aged sibling. What do you want to do next?

This infant may be ill from a number of possible causes, including viruses and bacterial infections that commonly appear during winter months. The differential diagnosis for a young child with a respiratory infection in February includes influenza, so you make sure to run a flu test. Although vaccinated children can be infected with various strains of influenza, children younger than six months old are particularly vulnerable because they cannot receive the flu vaccine before six months of age. You also send a swab for antigen testing because the child’s symptoms are consistent with bronchiolitis associated with respiratory syncytial virus (RSV) infection. The baby does not appear to have an ear infection, so the most likely culprits for his respiratory infection are viruses. When the test results come back after 20 minutes, the child has tested negative for flu and positive for RSV.

Professional guidelines recommend that people recently infected with influenza and infected people in high-risk populations receive antivirals such as oseltamivir (Tamiflu), zanamivir (Relenza), or peramivir (Rapivab). Of these three medications, oseltamivir is FDA approved for children older than 14 days old. However, most children with viral respiratory infections who do not have influenza should be managed with supportive care. In the case of RSV, support includes maintaining proper hydration by continuing regular feedings, running a properly cleaned humidifier, administering acetaminophen for fever, and possibly prescribing the use of nebulizers in children who respond to them.

The CDC encourages hand washing and covering coughs for prevention of RSV in most children and adults. The American Academy of Pediatrics recommends that providers consider administering palivizumab, a monoclonal antibody that can prevent RSV, to high-risk infants and young children with underlying medical conditions. Monthly intramuscular injections of palivizumab may prevent RSV infection in these children during the fall, winter, and spring when RSV is common in the United States.


Dr. V. Silverstein
Durham, NC

Published on 3/5/18