Introduction

Sepsis is a critical response to an infection, where the immune system, in its attempt to fight off the infection, ends up harming the body's tissues and organs. This condition, which is not contagious and cannot be transmitted from one person or animal to another, is a severe complication that arises when the body's response to an infection spirals out of control. Often referred to as septicaemia or blood poisoning, sepsis is a medical emergency that requires prompt attention.¹ Neonatal sepsis is a severe medical condition impacting newborns less than 28 days old. It occurs when a newborn's body mounts an excessive immune response to an infection, leading to widespread inflammation. This inflammation, coupled with blood clotting, can decrease blood flow to the infant's limbs and vital organs, potentially resulting in organ failure or even death.¹⁴ Neonatal sepsis is classified into two types:³

• Early-onset neonatal sepsis: This term is typically used to describe sepsis that manifests within the first 72 hours of the newborn's life
• Late-onset neonatal sepsis: This refers to sepsis occurring after the newborn's first three days of life

Epidemiology 

In 2010, globally, 7.6 million children under the age of 5 died, with a significant number of these deaths due to infectious causes, including sepsis. Notably, neonatal deaths, which occur in the first 28 days of life, made up 40% of these fatalities.⁵ Neonates born prematurely face the highest risk of sepsis, experiencing the greatest incidence and mortality rates compared to other age groups.⁶ Furthermore, preterm infants are at an up to 1000-fold greater risk of developing sepsis compared to full-term infants. This heightened vulnerability is also linked with increased mortality rates and a higher likelihood of enduring neurodevelopmental challenges throughout their lives.⁷

Risk factors 

Neonatal sepsis remains a significant cause of illness and death among infants, particularly in middle and lower-income countries.² While it can affect any newborn, premature babies are more susceptible to sepsis than those born at term. This increased risk is due to their underdeveloped immune systems.¹⁴ 

Premature babies lack the antibodies needed to fight off certain bacteria because they are born before they can acquire these antibodies from their birthing parent. Additionally, neonatal sepsis is more prevalent in infants with:¹⁴

• Low birth weight or 
• Those whose birthing mother has infections during pregnancy. 
• The need for invasive medical devices, like vascular access, endotracheal tubes, feeding tubes, and urinary catheters, which are often necessary for treating severe illnesses, also contributes to the higher incidence of sepsis in these babies

Aetiology and pathophysiology 

Early-onset sepsis 

It is typically caused by the transmission of infection from the birthing parent's genitourinary system to the newborn or fetus.⁴ These pathogens can travel up the vagina, cervix, and uterus, infecting the amniotic fluid. Neonates can contract these infections in the womb or as they pass through the vaginal canal during birth.⁴

Common bacteria responsible for Early-onset sepsis in infants include:⁴

• Group B streptococcus (GBS)
• Escherichia coli
• Staphylococcus
• Haemophilus influenzae

Factors in the birthing parent that heighten the risk of neonatal sepsis are conditions like:

• Chorioamnionitis
• Colonisation with GBS
• Preterm delivery before 37 weeks
• Prolonged rupture of membranes lasting more than 18 hours

Late-onset sepsis 

It is primarily acquired from the environment post-delivery, through contact with healthcare workers or caregivers. Some cases of late-onset sepsis might also stem from a delayed presentation of an infection transmitted vertically. Infants who undergo⁴

• Procedures like intravascular catheter insertion
• Breach of the mucosal barriers and face a higher risk of LOS

In developed countries, the Staphylococcus epidermidis, are implicated in over half of late-onset sepsis incidents. Yet, a variety of bacterial and viral pathogens can also cause late-onset sepsis.⁴

Viral infections, such as those caused by herpes simplex virus (HSV), and enteroviruses, can lead to early-onset neonatal sepsis, presenting a need for differentiation from bacterial sepsis.⁸ While fungal infections are rare in EOS, Candida species, especially in very low birth weight (VLBW) infants, are the most common fungal culprits when they do occur.⁹

Signs and symptoms 

The signs and symptoms of sepsis in newborns can vary depending on their gestational age and the infection's severity. 

It's rare for infants to present with a fever unless they've inherited it from a febrile mother immediately post-delivery. More commonly, a septic newborn may show signs of:⁴

• Lethargy
• Poor feeding 
• Hypothermia
• Anuria 
• Acidosis 
• Pneumonia
• Apnea
• Tachypnea, grunting
• Nasal flaring
• Intercostal retractions 
• Cyanosis
• Desaturation
• Bradycardia
• Poor perfusion
• Hypotension 
• Temperature instability
• Feeding difficulties

Diagnosis 

Neonates with sepsis might not show symptoms and could appear normal upon physical examination.¹⁰ Hence, laboratory tests are crucial for diagnosis. 

• Blood cultures are essential for neonates suspected of having sepsis¹⁰
• Urine cultures are typically not recommended for early-onset sepsis evaluation, they should also be considered for late-onset sepsis assessment¹¹
• Lumbar puncture for cerebrospinal fluid (CSF) analysis and culture is crucial for any infant with a positive blood culture or signs suggesting central nervous system involvement¹²
• Polymerase chain reaction (PCR), is being explored to identify sepsis and its causative organisms more rapidly than traditional blood cultures¹²
• Complete blood count (CBC) with differential and C-reactive protein (CRP) levels are routinely performed, though they're more effective at excluding neonatal sepsis than confirming it¹²
• Imaging tests like chest X-rays or ultrasounds may also be utilised¹⁴

Management and treatments 

Immediate action is crucial when treating neonatal sepsis. The baby may need to be admitted to an intensive care unit (ICU).⁷ Treatments for sepsis in newborns typically include:⁵

• Intravenous fluids
• IV antibiotics to combat bacterial infections
• Antiviral medications
• Cardiac support medications
• Additional respiratory support such as oxygen
• Blood transfusions

Prevention 

Obstetricians might recommend preventive antibiotics to avoid transmitting infections to the baby. Other helpful lifestyle modifications could be:¹⁴

• Adhering to good hygiene practices before, during, and after pregnancy
• Attending regular healthcare appointments
• Getting the important and prescribed vaccinations
• Learning about neonatal sepsis symptoms
• Seeking prompt medical help if sepsis is suspected can also be a preventive measure

Prognosis 

Neonatal sepsis is treatable, and many newborns who develop it recover fully without long-term issues.¹¹ However, it remains one of the leading causes of infant mortality. The sooner the treatment begins, the better the chances for a positive outcome.¹² The mortality risk from sepsis increases by approximately 7.6% with each hour of delayed treatment.¹⁴

FAQs

What complications can arise from neonatal sepsis?

• Infant mortality: The death rate from neonatal sepsis in term and late preterm infants is estimated to be between two to four per cent
• Meningitis: An inflammation of the protective membranes covering the brain and spinal cord, which can result from neonatal sepsis
• Developmental delays: These can occur in various areas, such as physical, social, or cognitive development
• Cerebral palsy: A group of permanent movement disorders that appear in early childhood, sometimes resulting from sepsis
• Seizure disorders: Conditions where brain activity becomes abnormal, potentially causing seizures.
• Hearing loss: This can be a consequence of neonatal sepsis and affect a child's ability to communicate and develop language skills¹⁵

Is it possible for a newborn to survive sepsis?

Yes, a newborn can survive sepsis. Medical professionals administer antibiotics through a cannula or line directly into a vein to treat any infections. Sepsis can progress rapidly, so prompt treatment is crucial. The sooner a baby receives treatment, the higher the likelihood of a complete recovery.¹⁶

Summary

Neonatal sepsis is a serious concern for newborns, particularly hard due to their not fully developed immune systems. This condition comes in two varieties: early-onset, typically passed from mother to baby during childbirth, and late-onset, which often arises from environmental sources post-birth. The range of symptoms is broad, emphasizing the need for swift diagnosis and treatment. The go-to treatment is usually antibiotics, crucial for tackling this potentially deadly issue. Preventive steps, such as giving antibiotics to mothers and ensuring strict hygiene, are vital in mitigating risks. While neonatal sepsis is a grave threat, quick and effective medical intervention can greatly boost the chances of recovery, stressing the importance of prompt and proper medical care.