An 8-hour-old infant develops increased respiratory distress, hypothermia, and hypotension. A complete blood count (CBC) demonstrates a white blood cell (WBC) count of 2500/μL with 80% bands. The chest radiograph is shown below. Which of the following is the most likely diagnosis?
- Congenital syphilis
- Diaphragmatic hernia
- Group B streptococcal pneumonia
- Transient tachypnea of the newborn
- Chlamydial pneumonia
The rapid onset of the symptoms, the low WBC count with left shift, and the depicted chest x-ray findings are typical of a patient with group B streptococcus (GBS) pneumonia. Appropriate management would include rapid recognition of symptoms, cardiorespiratory support, and rapid institution of appropriate antibiotics. Despite these measures, mortality from this infection is not uncommon. The other infectious causes listed do not present so early, and the noninfectious causes listed do not cause elevations in the band count. GBS disease in the infant is decreasing in incidence with better prevention strategies in the perinatal period, including early screening in pregnancy and treatment with antibiotics just prior to delivery to eliminate GBS colonization and, thus, markedly decrease the risk to the infant.
Congenital syphilis can cause pneumonia, but it is diagnosed at birth along with other features including hepatosplenomegaly, jaundice, rashes, hemolytic anemia, and others. Diaphragmatic hernia presents with early respiratory distress, but the diagnosis is confirmed clinically with bowel sounds heard in the chest and a radiograph that has loops of bowel located above the normal placement of the diaphragm. Transient tachypnea of the newborn (TTN) causes an increase in respiratory rate and occasionally a low oxygen requirement; the history is often positive for a cesarean delivery, and the radiograph shows retained fluid in the fissures. TTN does not cause temperature instability nor is the CBC abnormal. Chlamydial pneumonia is not a condition that occurs in an 8-hour-old infant; it is generally a mild pneumonia that can develop in an exposed infant at several weeks of life.