Neonatal_sepsis_flashcards
What is neonatal sepsis?
Neonatal sepsis occurs when a serious bacterial or viral infection in the blood affects babies within the first 28 days of life.
How is neonatal sepsis categorized?
Neonatal sepsis is categorized into early-onset (EOS, within 72 hours of birth) and late-onset (LOS, between 7-28 days of life).
What percentage of neonatal mortality is accounted for by neonatal sepsis?
Neonatal sepsis accounts for 10% of all neonatal mortality.
What is the incidence of neonatal sepsis in live births?
The incidence of neonatal sepsis is 1-5 per 1000 live births.
What is the incidence of neonatal sepsis in term neonates?
The incidence of neonatal sepsis in term neonates is 1-2 per 1000 live births.
What is the incidence of neonatal sepsis in late pre-term infants?
The incidence of neonatal sepsis in late pre-term infants is 5 per 1000 live births.
What is the incidence of neonatal sepsis in neonates with birth weight <2.5kg?
The incidence of neonatal sepsis in neonates with birth weight <2.5kg is 0.5 per 1000 live births.
What is an independent risk factor for group B streptococcus-related sepsis?
Black race is an independent risk factor for group B streptococcus-related sepsis.
What is the most common cause of neonatal sepsis?
The most common causes of neonatal sepsis are group B streptococcus (GBS) and Escherichia coli.
What percentage of early-onset sepsis in the UK is caused by GBS infection?
75% of early-onset sepsis in the UK is caused by GBS infection.
How does early-onset sepsis usually occur?
Early-onset sepsis usually occurs due to transmission of pathogens from the mother to the neonate during delivery.
How does late-onset sepsis usually occur?
Late-onset sepsis usually occurs via the transmission of pathogens from the environment post-delivery, normally from contacts such as parents or healthcare workers.
What are common infective causes of late-onset sepsis?
Common infective causes of late-onset sepsis are coagulase-negative staphylococcal species such as Staphylococcus epidermidis, Gram-negative bacteria such as Pseudomonas aeruginosa, Klebsiella, and Enterobacter, and fungal species.
What are less common causes of neonatal sepsis?
Less common causes of neonatal sepsis include Staphylococcus aureus, Enterococcus, Listeria monocytogenes, and viruses including herpes simplex and enterovirus.
What maternal factors increase the risk of neonatal sepsis?
Maternal risk factors include previous baby with GBS infection, current GBS colonization, bacteriuria, intrapartum temperature ≥38ºC, membrane rupture ≥18 hours, and infection during pregnancy.
What percentage of neonatal sepsis cases occur in premature neonates?
Approximately 85% of neonatal sepsis cases occur in premature neonates.
What percentage of neonatal sepsis cases occur in low birth weight neonates?
Approximately 80% of neonatal sepsis cases occur in low birth weight neonates.
What are common presentations of neonatal sepsis?
Common presentations include respiratory distress, grunting, nasal flaring, use of accessory respiratory muscles, tachypnea, tachycardia, apnea, lethargy, jaundice, seizures, poor feeding, abdominal distention, vomiting, and variable temperature.
What investigations are used to diagnose neonatal sepsis?
Investigations include blood culture, full blood examination, C-reactive protein, blood gases, urine microscopy, culture and sensitivity, and lumbar puncture.
What is the first-line antibiotic regimen recommended by NICE for suspected or confirmed neonatal sepsis?
NICE recommends intravenous benzylpenicillin with gentamicin as a first-line regimen.
When should CRP be re-measured in neonates given antibiotics?
CRP should be re-measured 18-24 hours after presentation.
When can antibiotics be ceased in neonates with neonatal sepsis?
Antibiotics can be ceased at 48 hours in neonates with CRP <10 mg/L and a negative blood culture at presentation and at 48 hours.
What other management factors should be considered in neonatal sepsis?
Other management factors include maintaining adequate oxygenation status, normal fluid and electrolyte status, preventing/managing hypoglycemia and metabolic acidosis.
summarise neonatal sepsis
Neonatal sepsis
Neonatal sepsis occurs when a serious bacterial or viral infection in the blood affects babies within the first 28 days of life. Neonatal sepsis is categorised into early-onset (EOS, within 72 hours of birth) and late-onset (LOS, between 7-28 days of life) sepsis, with each category tending to have a distinct group of causes and common presentations. Neonatal sepsis account for 10% of all neonatal mortality and therefore must be promptly identified and managed to prevent significant consequences, as untreated, the mortality can be very high.
Epidemiology
Male:female incidence 1:1
Incidence of neonatal sepsis: 1-5 per 1000 live births
Term neonates: 1-2 per 1000 live births
Late pre-term infants: 5 per 1000 live births
Birth weight <2.5kg: 0.5 per 1000 live births
Black race is an independent risk factor for group B streptococcus-related sepsis
Causes
Neonatal infection is present in 8 per 1000 live births (note: this is the incidence of neonatal infection, not yet necessarily progressed to neonatal sepsis), and is the key factor which leads to subsequent life-threatening neonatal sepsis
The overall most common causes of neonatal sepsis are group B streptococcus (GBS) and Escherichia coli, accounting for approximately two thirds of neonatal sepsis cases
Early-onset sepsis in the UK is primarily caused by GBS infection (75%)
Infective causes in early-onset sepsis are usually due to transmission of pathogens from the mother to the neonate during delivery
Late-onset sepsis usually occurs via the transmission of pathogens from the environment post-delivery, this is normally from contacts such as the parents or healthcare workers
Infective causes are more commonly coagulase-negative staphylococcal species such as Staphylococcus epidermidis, Gram-negative bacteria such as Pseudomonas aeruginosa, Klebsiella and Enterobacter, and fungal species
Other less common causes include:
Staphylococcus aureus
Enterococcus
Listeria monocytogenes
Viruses including herpes simplex and enterovirus
Risk factors
Mother who has had a previous baby with GBS infection, who has current GBS colonisation from prenatal screening, current bacteruria, intrapartum temperature ≥38ºC, membrane rupture ≥18 hours, or current infection throughout pregnancy
Premature (<37 weeks): approximately 85% of neonatal sepsis cases are in premature neonates
Low birth weight (<2.5kg): approximately 80% are low birth weight
Evidence of maternal chorioamnionitis
Patients typically present with a subacute onset of:
Respiratory distress (85%)
Grunting
Nasal flaring
Use of accessory respiratory muscles
Tachypnoea
Tachycardia: common, but non-specific
Apnoea (40%)
Apparent change in mental status/lethargy
Jaundice (35%)
Seizures (35%): if cause of sepsis is meningitis
Poor/reduced feeding (30%)
Abdominal distention (20%)
Vomiting (25%)
Temperature: not usually a reliable sign as the temperature can vary from being raised, lowered or normal
Term infants are more likely to be febrile
Pre-term infants are more likely to be hypothermic
The clinical presentation can vary from very subtle signs of illness to clear septic shock
Frequently, the symptoms will be related to the source of infection (e.g. pneumonia + respiratory symptoms, meningitis + neurological symptoms)
Investigations:
Blood culture: this will usually establish the diagnosis, as the sensitivity for septicaemia is around 90%. Should usually obtain two blood cultures if possible to distinguish from contamination, however one culture is still sufficient depending on hospital protocol
Full blood examination: neonatal sepsis is often associated with abnormal neutrophil counts (both neutrophilia and neutropenia), however in neonates, parameters on full blood examination are usually not always useful for diagnosis, rather may help to exclude healthy neonates
C-reactive protein: not useful for diagnosis, but sequential assessment will help to guide management and patient progress with treatment. CRP will usually be raised, and a persistently normal level is likely to exclude neonatal sepsis
Blood gases: metabolic acidosis is particularly concerning for neonatal sepsis, particularly a base deficit of ≥10 mmol/L
Urine microscopy, culture and sensitivity: rarely positive in EOS, more useful in LOS. Will show signs of infection (e.g. raised leukocytes, positive culture, haematuria, proteinuria) if urinary tract infection is the source of sepsis
Lumbar puncture: particularly if there is concern of meningitis as the source of sepsis based on clinical features, however many hospitals will require lumbar puncture as part of a septic screen in any baby below the age of 28 days
Management
In neonatal sepsis, the most important part of management to improve outcomes is early identification and treatment
The NICE guidelines recommend use of intravenous benzylpenicillin with gentamicin as a first-line regimen for suspected or confirmed neonatal sepsis
The exception to this is if microbiological surveillance data reveal local bacterial resistance patterns, in which case an alternative antibiotic should be considered
CRP should be re-measured 18-24 hours after presentation in babies given antibiotics to monitor ongoing progress and guide duration of therapy
The evidence suggests that antibiotics can be ceased at 48 hours in neonates who have CRP of <10 mg/L and a negative blood culture at presentation and at 48 hours
In all other neonates, the duration of antibiotic treatment will depend on the ongoing investigations and clinical picture, this will involve specialist decision making. Normally, in neonates with culture-proven sepsis, duration will be approximately 10 days
Other important management factors to consider include:
Maintaining adequate oxygenation status
Maintaining normal fluid and electrolyte status: severely ill neonates may require volume and/or vasopressor support. Body weight needs to be measured daily for accurate assessment of fluid status
Prevention and/or management of hypoglycaemia
Prevention and/or management of metabolic acidosis
A 6-day-old baby is admitted to the neonatal intensive care unit after having difficulty breathing in the last 24 hours. She was born at 39 weeks gestation weighing 2.0 kg with no complications during pregnancy. Her mother had an episode of tonsillitis that resolved spontaneously. The baby and her parents are of Bengali ethnicity but have lived in the UK their whole lives.
On examination, there is nasal flaring and the baby is using accessory muscles to breathe. She is tachycardic and tachypnoeic and looks fatigued.
Given the likely diagnosis, what factor has most likely contributed to its development?
Her birth weight
Her ethnicity
Her sex
Presence of Streptococcus pyogenes in the mother
The number of weeks gestation she was delivered at
Low birth weight is a risk factor for neonatal sepsis
Features such as difficulty breathing, poor feeding, lethargy, apnoea, and vomiting in a neonate that is aged up to 28 days old should raise suspicion of neonatal sepsis. This is because early symptoms are vague, and the features of sepsis usually seen in adults (such as haemodynamic instability and hypotension) are not seen until very late stages. The most common features seen in neonatal sepsis include respiratory distress (such as grunting, nasal flaring, using accessory muscles, and tachypnoea), followed by tachycardia, apnoea, appetite and behavioural changes, poor feeding, and vomiting.
Her birth weight is correct as a low birth weight (<2.5 kg) is a significant risk factor for neonatal sepsis, and around 80% of neonates affected have a low birth weight.
Her ethnicity is incorrect. Although coming from a developing country may increase one’s risk of neonatal sepsis, the neonate and her family have lived in the UK their entire lives. Furthermore, there is not much evidence suggesting those of Bangladeshi ethnicity are inherently at increased risk. People of Black ethnicity are at an increased risk of group B Streptococcus-related sepsis.
Her sex is incorrect as the male-to-female incidence ratio is 1:1, therefore not making her sex a significant risk factor.
Presence of Streptococcus pyogenes in the mother is incorrect. The organism associated with neonatal sepsis is group B Streptococcus (Streptococcus agalactiae), rather than Streptococcus pyogenes, which belongs to group A Streptococcus species. Streptococcus pyogenes is not as strongly associated with neonatal sepsis compared to group B Streptococcus. This is because group B Streptococcus can be part of the normal vaginal microbiota in many women, increasing the risk of transmission.
The number of weeks gestation she was delivered at is incorrect. Although prematurity is a risk factor for neonatal sepsis, this is considered as birth at <37 weeks gestation. This neonate was born at 39 weeks gestation, therefore, she is not premature.
A 3-week-old boy is brought into the emergency department by his parents. They are really worried about the baby’s health as he appears to have deteriorated over the past day. He started eating less than half his bottle this morning, and by this evening, he has becoming inconsolable, feverish and has difficulty breathing.
He was born prematurely at 35 weeks, and stayed in the neonatal intensive care unit for 2 weeks on ventilation. The pregnancy was normal, until the mother went into labour prematurely.
You do an examination and find that as well being very unsettled, you hear grunting and see intercostal recession. He is tachycardic and has a temperature of 38.9ºC, despite looking mottled. You notice he has decreased skin turgor and a sunken fontanelle, but no rash.
What is the most likely diagnosis?
Bronchopulmonary dysplasia
Meningitis
Necrotising enterocolitis
Neonatal sepsis
Respiratory distress syndrome
Neonatal sepsis
Grunting and other signs of respiratory distress are the most common presentation of neonatal sepsis
The most likely diagnosis here is neonatal sepsis given the high fever, inconsolable crying dehydration and respiratory distress. This baby has many of the red (high risk) features of the traffic light system for identifying serious illness, and must be admitted and treated as an emergency.
The classic signs of meningitis (headache, neck stiffness and photophobia) are difficult to identify in young children and babies who cannot express their symptoms. Therefore, you must have a low suspicion for meningitis. Signs include a bulging fontanelle, inconsolable crying, rash and high fever.
Prematurity is a major risk factor for necrotising enterocolitis, however, it presents with abdominal distension, pain, bloody stools and feeding intolerance.
Respiratory distress syndrome in neonates occurs when lungs are underdeveloped, thus prematurity is a significant risk factor. However, this is less likely to present with fever, mottled skin and dehydration.
Finally, bronchopulmonary dysplasia is another term for chronic lung disease. Prematurity and being on ventilation are risk factors as these can damage the lung. This presents with respiratory distress and cyanosis.
A 3-day-old baby is brought to the ED by his parents due to concerns about his breathing. Over the past 12 hours, the baby has shown signs of grunting and intercostal recession. He also appears lethargic and jaundiced. Neonatal sepsis is confirmed with blood cultures.
The baby was delivered at home via spontaneous vaginal delivery at 41 weeks. He weighed 3.6 kg at birth and was in breech presentation at 36 weeks gestation. Maternal screening was positive for Streptococcus agalactiae.
What is the most important risk factor for the development of his condition?
Being born at 41 weeks
Breech presentation at 36 weeks
Maternal Streptococcus agalactiae positivity
Vaginal delivery
Weight of 3.6 kilograms at birth
Maternal Group B Streptoccocus is a risk factor for neonatal sepsis
The correct answer is maternal Streptococcus agalactiae positivity. The neonate in question displays symptoms such as grunting, intercostal recession, jaundice, and lethargy. These clinical signs are indicative of neonatal sepsis, a grave condition characterised by bacterial or viral infection within the bloodstream that predominantly affects infants within their first 28 days of life. Neonatal sepsis can manifest through a spectrum of clinical presentations, ranging from subtle signs to overt septic shock.
In this scenario, the infant was delivered at home through vaginal birth at term with a normal birth weight. However, it is noted that the mother tested positive for Streptococcus agalactiae, commonly referred to as group B streptococcus, which constitutes a significant risk factor for neonatal sepsis. Ideally, intravenous antibiotics should have been administered during labour to reduce the risk of transmission; unfortunately, this precaution was not taken due to the circumstances surrounding the home delivery. Consequently, maternal group B streptococcus carriage stands out as the predominant risk factor in this case.
Being born at 41 weeks is not associated with an increased risk of neonatal sepsis; rather, it falls within the definition of a term delivery. Prematurity—defined as birth before 37 weeks gestation—is more closely linked with neonatal sepsis, accounting for approximately 85% of cases. This higher susceptibility in premature infants can be attributed primarily to their underdeveloped immune systems and consequent heightened vulnerability to infections.
Breech presentation at 36 weeks does not correlate with an elevated risk for neonatal sepsis. While breech presentation is considered a risk factor for developmental dysplasia of the hip—which necessitates an ultrasound examination six weeks postpartum—it bears no association with sepsis in newborns.
Vaginal delivery, similarly, has not been shown to increase the likelihood of developing neonatal sepsis when compared with other modes of delivery.
A birth weight of 3.6 kilograms does not imply an increased risk for neonatal sepsis; this figure represents a normal birth weight. On the contrary, low birth weight—defined as less than 2.5 kilograms—is associated with a higher incidence rate of neonatal sepsis; about 80% of affected infants are those who fall below this threshold.
