An 8-hour-old term infant develops increased respiratory distress, hypothermia, and hypotension. A complete blood count (CBC) demonstrates a white blood cell (WBC) count of 2500/mL with 80% bands. The chest radiograph is shown below. Which of the following is the most likely diagnosis?
**Core Concept**
Group B streptococcal (GBS) pneumonia is a serious bacterial infection caused by Streptococcus agalactiae, commonly affecting newborns, especially within the first 72 hours of life. GBS colonization in the mother's vagina and/or rectum can lead to vertical transmission during delivery, resulting in neonatal infection.
**Why the Correct Answer is Right**
The clinical presentation of increased respiratory distress, hypothermia, and hypotension in an 8-hour-old term infant is consistent with GBS pneumonia. The CBC results, showing a WBC count of 2500/mL with 80% bands, indicate a severe bacterial infection. The chest radiograph findings are not provided, but in GBS pneumonia, radiographic features such as diffuse interstitial infiltrates, patchy consolidation, or pleural effusions may be observed.
Option C is the correct answer because GBS pneumonia is a well-established cause of severe neonatal infection, characterized by respiratory distress, hypothermia, and hypotension. The presence of bandemia (increased number of band neutrophils) in the CBC supports a bacterial infection, which is consistent with GBS pneumonia.
**Why Each Wrong Option is Incorrect**
**Option A:** Congenital syphilis typically presents with skin rashes, hepatosplenomegaly, and rhinitis in the first few weeks of life, not with respiratory distress and hypotension as seen in this infant.
**Option B:** Diaphragmatic hernia would typically present with severe respiratory distress, often within the first hour of life, and would be accompanied by abdominal contents in the chest on a chest radiograph.
**Option D:** Transient tachypnea of the newborn (TTN) usually presents with mild respiratory distress, not severe respiratory distress as seen in this infant. TTN is often associated with a normal or slightly elevated WBC count, not bandemia.
**Clinical Pearl / High-Yield Fact**
In neonates, it's essential to consider GBS pneumonia in the differential diagnosis of respiratory distress, especially if the infant is less than 72 hours old and has a CBC showing bandemia.
**✓ Correct Answer: C. Group B streptococcal pneumonia**