What is Neonatal Sepsis?
Neonatal sepsis is a blood infection that affects newborns who are less than 28 days old. It’s one of the primary factors contributing to sickness and death in newborns, particularly in countries with middle and lower incomes. This infection is broken down into two categories, based on when the baby starts showing symptoms after birth: early-onset sepsis (EOS) and late-onset sepsis (LOS).
EOS is when the baby gets an infection within the first 72 hours of their life (some experts extend this period to 7 days). On the other hand, LOS refers to infections that happen at or after 72 hours following the baby’s birth.
What Causes Neonatal Sepsis?
EOS, or early-onset sepsis, usually happens when harmful micro-organisms from the mother’s reproductive system are transmitted to the baby. These harmful organisms can travel from the vagina, the cervix, and the uterus, and can even infect the amniotic fluid which is the fluid that surrounds the baby in the womb. Babies can get infected either while they’re still in the womb or during delivery as they pass through the vaginal canal. Common bacteria that cause EOS include group B streptococcus (GBS), Escherichia coli, coagulase-negative Staphylococcus, Haemophilus influenza, and Listeria monocytogenes. Factors that can increase the newborn’s risk of getting sepsis include inflammation of the membranes around the fetus (chorioamnionitis), presence of GBS in the mother, early delivery before 37 weeks of pregnancy, and rupture of membranes for more than 18 hours.
LOS, or late-onset sepsis, typically occurs when harmful organisms from the environment after delivery, such as from healthcare workers or caregivers, are transmitted to the baby. A part of LOS also happens due to an infection the baby got while in the womb showing up late. Babies who need invasive procedures like insertion of tubes into their blood vessels, any other procedures that disturb the inner lining of their organs, are at a higher risk for getting LOS.
Premature babies are generally at a higher risk of getting infections compared to full-term babies. This heightened risk is mostly because their immune systems aren’t fully developed. They lack enough antibodies to fight off infections (decreased IgG antibodies), their bodies’ ability to kill foreign substances (incompetent opsonization and complement activation) is inefficient, and the inner lining of their organs isn’t fully developed. Also, they often require various tubes due to illnesses they can be prone to, like tubes for blood vessel access, tubes to assist with breathing, feeding tubes, and catheters for their urinary tract.
A type of bacteria known as coagulase-negative staphylococcal species, especially Staphylococcus epidermis, causes over 50% of LOS cases in developed countries. However, many different types of bacterial and viral organisms can cause LOS.
Risk Factors and Frequency for Neonatal Sepsis
Neonatal sepsis, a severe infection in newborn babies, has seen some changes in its trends over time. Since the 1990s, there has been a decline in early-onset sepsis (EOS) due to specific screening for Group B Streptococcus (GBS) in pregnant women and the use of antibiotics during childbirth. Unfortunately, the rates of late-onset sepsis (LOS) have not seen a similar improvement and have stayed somewhat the same. Nowadays, Escherichia coli, a type of bacteria, is a more common cause of EOS.
- The estimated incidence of EOS in the U.S. ranges between 0.77 to 1 per 1,000 live births.
- There’s a common practice of testing newborns for sepsis if they have certain risk factors or show certain symptoms.
- About 7% to 13% of all newborns are treated for sepsis, even though only 3% to 8% have positive cultures confirming the infection.
- The lower rate of positive cultures could be due to antibiotics given to the mother and the small amount of blood collected for testing in newborns.
- Premature babies and babies with very low birth weight (less than 1000 grams) have a higher chance of developing sepsis.
- African American infants are at a higher risk of getting GBS and LOS, likely due to higher carrier rates of GBS among African American females.
- Males tend to have a higher likelihood of getting sepsis and meningitis, especially from gram-negative enteric bacteria.
Signs and Symptoms of Neonatal Sepsis
Neonatal sepsis presents with various symptoms ranging from general signs like irritability, fatigue, and poor feeding, to serious conditions such as respiratory distress, fever, low body temperature, or low blood pressure. In some cases, infants who are seemingly well may be diagnosed with sepsis based on abnormal lab results, which could indicate conditions like high or low blood sugar, acidosis, or higher than normal bilirubin levels. As these symptoms can be vague, it is crucial for doctors to be vigilant and take into account risk factors when diagnosing sepsis in newborns. Risk factors include low birth weight, premature birth, or if the mother had certain conditions or infections during pregnancy such as GBS or chorioamnionitis. Risks can also be increased if the baby has medical equipment inside the body, like a central venous catheter or endotracheal tube, relies on parenteral nutrition, or is taking certain medications like proton-pump inhibitors or histamine-2 blocking therapy.
Testing for Neonatal Sepsis
Newborns with possible bloodstream infections may not show any noticeable signs. Therefore, special laboratory tests play a crucial role in detection. If your baby is suspected to have a serious condition known as sepsis, which is a severe infection that can spread throughout the body, your doctor would recommend a blood culture straight away. This test requires at least 1 ml of blood, as smaller amounts might not adequately detect the infection.
If a catheter (a small, thin tube) is being used on your baby, the doctor would also recommend taking samples from around the catheter site. While urine tests are normally not considered necessary for very early sepsis detection, they are often considered for late-onset sepsis. In some cases, the doctor might also suggest a lumbar puncture. This test retrieves fluid from around the spinal cord (cerebrospinal fluid or CSF) for testing, especially if there’s a possibility of infection in the central nervous system (brain or spinal cord area).
A CSF test can provide several useful pieces of information. It can show if there’s an increase in protein levels and white blood cells (WBC), both of which might indicate infection or inflammation. Moreover, it can show if there are any bacteria present or a decrease in glucose (a vital energy source) concentration.
Other tests that the doctor might order include a complete blood count with differential, often taken several times, and a C-reactive protein test. While these tests might not be the best at detecting neonatal sepsis, they can be effective at ruling it out. Lower than average (neutropenic) neutrophils, (a type of white blood cell that aids with infection prevention) is often a better sign of neonatal sepsis than an excessively high count (neutrophilia).
At times, newborns might have elevated immature to total neutrophil counts, but this doesn’t necessarily mean they have sepsis. These counts might naturally be higher immediately after birth, hence blood count tests might be delayed for 6 to 12 hours after delivery to ensure accurate results.
C-reactive protein is another helpful substance that increases 6 to 8 hours after an infection begins and reaches its peak around 24 hours. If the levels remain normal, it strongly suggests no bacterial sepsis. If your doctor suspects sepsis, they might also recommend tests for other inflammatory markers such as procalcitonin, haptoglobin, and cytokines. In addition, if your baby has any respiratory symptoms, a chest X-ray might be suggested to look for any lung-related issues.
Treatment Options for Neonatal Sepsis
When a newborn is suspected to have sepsis (a severe body-wide response to bacterial infection), it’s important to start treatment with antibiotics right away, even if there isn’t yet lab confirmation. Often, the likely cause of the infection dictates which antibiotic is initially chosen, with doctors considering common resistance patterns (how well bacteria might resist treatment) within the unit taking care of the baby.
In many cases, the initial treatment includes antibiotics like ampicillin and aminoglycosides, administered directly into the bloodstream. These are used to combat the type of bacteria most commonly involved in early-onset newborn sepsis (sepsis that occurs within the first week of life), like Group B Strep, E. coli, and Listeria.
If the infection is suspected to develop later, after the first week of life (known as late-onset sepsis), different bacteria are often involved. These infections can typically be acquired in the hospital and include bacteria like Staphylococcus and Pseudomonas. To treat these, a combination of the antibiotic vancomycin and aminoglycoside is usually recommended.
If the infection is suspected to have spread to the central nervous system (the brain and spinal cord), a third type of antibiotic, called cephalosporins, might be considered. However, one particular cephalosporin called ceftriaxone should be avoided as it can lead to increased bilirubin (a substance that can cause jaundice) and the formation of particular types of crystals.
It’s also important to note that with the rising issue of antibiotic resistance (where bacteria are able to survive and grow in the presence of antibiotics), there are teams in place in hospitals to ensure antibiotics are used rationally. They help to avoid giving the baby antibiotics for longer than necessary, as excessive and unjustified use can contribute to the problem of resistance.
What else can Neonatal Sepsis be?
Because the symptoms of neonatal sepsis (a bacterial infection in the blood) can be quite vague, doctors have to consider several other health problems that might be causing similar symptoms. These potential conditions include:
- Infections caused by viruses, fungi, or parasites
- Congenital heart disease (heart disease present at birth)
- Neonatal encephalopathy (problems with a newborn’s brain function)
- Metabolic disorders
- Premature birth and related problems such as respiratory distress syndrome, intraventricular hemorrhage (bleeding in the brain), apnea of prematurity (brief pauses in breathing), and others
- Underactive or overactive thyroid (hypo or hyperthyroidism)
- Transient tachypnea of the newborn (fast breathing due to extra fluid in the lungs)
- Meconium aspiration (breathing in stool during or near childbirth)
- Low blood sugar (hypoglycemia)
What to expect with Neonatal Sepsis
The chances of survival can vary depending on how early a baby is born, with babies born prematurely (before their due date) having a higher risk of passing away compared to those born at full term (after 37 weeks of pregnancy). Certain bacteria like E.coli have been found to increase this risk further.
However, there have been medical advancements like the introduction of antibiotics during labour (referred to as intrapartum antibiotic prophylaxis) which can protect against a common bacteria called Group B Streptococcus (GBS). This has resulted in fewer babies passing away from GBS infections. Similarly, treating babies who show signs of illness, even when their tests do not show any bacteria, has also reduced the number of deaths.
Babies born prematurely who develop an infection (sepsis) may end up having difficulties with their brain development or may have sight problems. If these babies are treated with a certain type of antibiotic called aminoglycosides, they could also potentially face hearing loss (ototoxicity) and kidney damage (nephrotoxicity).
Possible Complications When Diagnosed with Neonatal Sepsis
Neonatal sepsis, or a severe infection in newborns, is still a major cause of health issues and death among newborns. Premature birth and delayed treatment are common factors linked with negative outcomes. Newborns with very low birth weight (VLBW) are found to be at a higher risk of developing chronic lung diseases. Moreover, babies with extremely low weights at birth are more likely to face risks related to brain development, such as hearing and vision problems, cerebral palsy, and slower mental and motor development.
On the flip side, the inappropriate overuse of antibiotics could lead to the development of severe fungal infections, like candidiasis, and cause germs which are resistant to many drugs to emerge.
Common Challenges:
- Premature birth
- Delayed treatment
- Chronic lung disease in very low birth weight (VLBW) babies
- Neurodevelopmental problems in extremely low birth weight babies including:
- Hearing and visual deficits
- Cerebral palsy
- Impaired psychomotor and mental development
- Overuse of antibiotics leading to:
- Severe fungal infections, like candidiasis
- Emergence of multi-drug resistant organisms
Preventing Neonatal Sepsis
Explaining to a newborn’s family about the illness and keeping them up-to-date through the course of treatment is a crucial part of caring for the child. Neonatal sepsis, an infection in a newborn, can be alarming and unexpected for parents and those who care for the baby. It’s important for doctors to remember this and make sure that parents know about all the tests that need to be done, why those tests are necessary, and what the results mean. Any changes in the antibiotics or treatment plan need to be thoroughly explained to the parents.
When you bring your newborn home from the hospital, it’s vital for parents and other caregivers, whether your child is healthy or has been ill, to know the warning signs of sickness or sepsis. Look out for symptoms like fever, yellowing skin or eyes (jaundice), increased sleepiness, changes in their feeding patterns, difficulty breathing or faster breathing, and bluish color in the fingertips and toes. Parents should contact their doctor if the newborn shows any of these signs, as they could indicate late-onset sepsis.
