Infections

It is always important to consider sepsis in the evaluation of a neonate with cyanosis. Sepsis results in cyanosis secondary to increased oxygen utilization. Patients at highest risk for sepsis are those born to group B streptococcus (GBS)–positive mothers, those with a history of maternal infection/chorioamniotitis, prolonged rupture of membranes for more than 18 hours, and those born prematurely. The most common pathogens in neonatal sepsis include E. coli, GBS, and Listeria monocytogenes.

History

A cyanotic infant presenting to the emergency department can have a life-threatening condition. The history should focus on the risk factors for congenital heart disease, respiratory disorders, hemoglobinopathies, and infectious diseases. Address prenatal risk factors, such as family history, maternal medications (e.g., lithium), maternal GBS status, maternal medical conditions (e.g., systemic lupus erythematosis), and ultrasound findings of congenital anomalies. Perinatal risk factors, such as maternal infection, should also be considered. Address postnatal issues, such as feeding intolerance, poor weight gain/excess weight gain, sweating/tiring with feeds, respiratory distress, NICU stay, prematurity, hypothermia, and hyperthermia. If the physician suspects methemoglobinemia, explore risk factors by asking about potential exposures to oxidizing substances.

Evaluation

Based on the initial visual assessment of appearance, work of breathing, and circulation (often referred to as the Pediatric Assessment Triangle), one can often quickly categorize the severity of illness. Infants with cyanotic CHD may appear to have decreased tone and alertness, increased irritability, and/or a weak cry. They may exhibit an increased work of breathing, abnormal airway sounds, retractions, and/or head bobbing.

Evaluating the infant’s work of breathing can be extremely helpful, as infants with respiratory disorders typically present with cyanosis in respiratory distress (associated with retractions), whereas infants with cardiac disorders and methemoglobinimia may present with cyanosis without significant distress. On skin exam, the infant may exhibit pallor, mottling, and/or cyanosis.

Although every workup should be tailored to the specific differential diagnosis being considered, it is a good idea to start any neonatal cyanosis workup by obtaining the following:

• Vital signs, including a rectal temperature and four-limb blood pressures.
• Baseline pulse oximetry reading (pre- and postductal) on room air (and on 100% oxygen, if low on room air).
• EKG.
• Bedside glucose reading.
• Intravenous access.
• CBC.
• Complete metabolic panel.
• Arterial blood gas.
• Chest radiograph.

The physician should note the heart rate, heart sounds, and breath sounds; palpate the precordium for thrills; palpate the peripheral pulses; note the skin quality and capillary refill; evaluate for surgical scars; auscultate the head, chest, and abdomen for bruits, murmurs, and gallops; and assess for hepatomegaly. Of note, murmurs are not present in all clinically significant cardiac lesions. For example, transposition of the great arteries will often not present with a murmur.