Neonatal sepsis
Encyclopedia
In common clinical usage, neonatal sepsis specifically refers to the presence of a bacterial blood stream infection
(BSI) (such as meningitis
, pneumonia
, pyelonephritis
, or gastroenteritis
) in the setting of fever. Criteria with regards to hemodynamic compromise or respiratory failure are not useful clinically because these symptoms often do not arise in neonates until death is imminent and unpreventable.
It is difficult to clinically exclude sepsis in newborns less than 90 days old that have fever (defined as a temperature > 38°C (100.4°F). Except in the case of obvious acute viral bronchiolitis
, the current practice in newborns less than 30 days old is to perform a complete workup including complete blood count
with differential, blood culture, urinalysis
, urine culture, and cerebrospinal fluid
(CSF) studies and CSF culture, admit the newborn to the hospital, and treat empirically for serious bacterial infection for at least 48 hours until cultures are demonstrated to show no growth. Attempts have been made to see whether it is possible to risk stratify newborns in order to decide if a newborn can be safely monitored at home without treatment despite having a fever. One such attempt is the Rochester criteria.
, showed that infants ≤ 60 days old meeting the following criteria were at low-risk for having a serious bacterial illness:
Those meeting these criteria likely do not require a lumbar puncture, and are felt to be safe for discharge home without antibiotic treatment, or with a single dose of intramuscular antibiotics, but will still require close outpatient follow-up.
antibiotic (usually ampicillin
) in combination with an aminoglycoside
(usually gentamicin
) or a third-generation cephalosporin
(usually cefotaxime
—ceftriaxone
is generally avoided in neonates due to the theoretical risk of kernicterus
.) The organisms which are targeted are species that predominate in the female genitourinary tract and to which neonates are especially vulnerable to, specifically Group B Streptococcus
, Escherichia coli
, and Listeria monocytogenes (This is the main rationale for using ampicillin versus other beta-lactams.) Of course, neonates are also vulnerable to other common pathogens that can cause meningitis
and bacteremia
such as Streptococcus pneumoniae
and Neisseria meningitidis
. Although uncommon, if anaerobic species are suspected (such as in cases where necrotizing enterocolitis
or intestinal perforation is a concern, clindamycin
is often added.
Granulocyte-macrophage colony stimulating factor (GM-CSF) is often used in neonatal sepsis, however a recent study found that, while GM-CSF corrects neutropenia if present, it has no effect on reducing sepsis or improving survival.
Bacteremia
Bacteremia is the presence of bacteria in the blood. The blood is normally a sterile environment, so the detection of bacteria in the blood is always abnormal....
(BSI) (such as meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
, pneumonia
Pneumonia
Pneumonia is an inflammatory condition of the lung—especially affecting the microscopic air sacs —associated with fever, chest symptoms, and a lack of air space on a chest X-ray. Pneumonia is typically caused by an infection but there are a number of other causes...
, pyelonephritis
Pyelonephritis
Pyelonephritis is an ascending urinary tract infection that has reached the pyelum or pelvis of the kidney. It is a form of nephritis that is also referred to as pyelitis...
, or gastroenteritis
Gastroenteritis
Gastroenteritis is marked by severe inflammation of the gastrointestinal tract involving both the stomach and small intestine resulting in acute diarrhea and vomiting. It can be transferred by contact with contaminated food and water...
) in the setting of fever. Criteria with regards to hemodynamic compromise or respiratory failure are not useful clinically because these symptoms often do not arise in neonates until death is imminent and unpreventable.
It is difficult to clinically exclude sepsis in newborns less than 90 days old that have fever (defined as a temperature > 38°C (100.4°F). Except in the case of obvious acute viral bronchiolitis
Bronchiolitis
Bronchiolitis is inflammation of the bronchioles, the smallest air passages of the lungs. It usually occurs in children less than two years of age and presents with coughing, wheezing, and shortness of breath. This inflammation is usually caused by viruses...
, the current practice in newborns less than 30 days old is to perform a complete workup including complete blood count
Complete blood count
A complete blood count , also known as full blood count or full blood exam or blood panel, is a test panel requested by a doctor or other medical professional that gives information about the cells in a patient's blood...
with differential, blood culture, urinalysis
Urinalysis
A urinalysis , also known as Routine and Microscopy , is an array of tests performed on urine, and one of the most common methods of medical diagnosis...
, urine culture, and cerebrospinal fluid
Cerebrospinal fluid
Cerebrospinal fluid , Liquor cerebrospinalis, is a clear, colorless, bodily fluid, that occupies the subarachnoid space and the ventricular system around and inside the brain and spinal cord...
(CSF) studies and CSF culture, admit the newborn to the hospital, and treat empirically for serious bacterial infection for at least 48 hours until cultures are demonstrated to show no growth. Attempts have been made to see whether it is possible to risk stratify newborns in order to decide if a newborn can be safely monitored at home without treatment despite having a fever. One such attempt is the Rochester criteria.
Risk factors
A study performed at Strong Memorial Hospital in Rochester, New YorkRochester, New York
Rochester is a city in Monroe County, New York, south of Lake Ontario in the United States. Known as The World's Image Centre, it was also once known as The Flour City, and more recently as The Flower City...
, showed that infants ≤ 60 days old meeting the following criteria were at low-risk for having a serious bacterial illness:
- generally well-appearing
- previously healthy
- full term (at ≥37 weeks gestation)
- no antibiotics perinatally
- no unexplained hyperbilirubinemia that required treatment
- no antibiotics since discharge
- no hospitalizations
- no chronic illness
- discharged at the same time or before the mother
- no evidence of skin, soft tissue, bone, joint, or ear infection
- WBC count 5,000-15,000/mm3
- absolute band count ≤ 1,500/mm3
- urine WBC count ≤ 10 per high power field (hpf)
- stool WBC count ≤ 5 per high power field (hpf) only in infants with diarrhea
Those meeting these criteria likely do not require a lumbar puncture, and are felt to be safe for discharge home without antibiotic treatment, or with a single dose of intramuscular antibiotics, but will still require close outpatient follow-up.
Diagnosis
Neonatal sepsis screening:- DLC showing increased numbers of polymorphs.
- DLC: band cells > 20%.
- increased haptoglobins.
- micro ESR (Erythrocyte Sedimentation Rate) titer > 55mm.
- gastric aspirate showing > 5 polymorphs per high power field.
- newborn CSF (CerebroSpinal Fluid) screen: showing increased cells and proteins.
- suggestive history of chorioamnionitis, PROM (Premature Rupture Of Membranes), etc...
Treatment
Note that, in neonates, sepsis is difficult to diagnose clinically. They may be relatively asymptomatic until hemodynamic and respiratory collapse is imminent, so, if there is even a remote suspicion of sepsis, they are frequently treated with antibiotics empirically until cultures are sufficiently proven to be negative. In addition to fluid resuscitation and supportive care, a common antibiotic regimen in infants with suspected sepsis is a beta-lactamBeta-lactam
A β-lactam ring, is a four-membered lactam. It is named as such, because the nitrogen atom is attached to the β-carbon relative to the carbonyl...
antibiotic (usually ampicillin
Ampicillin
Ampicillin is a beta-lactam antibiotic that has been used extensively to treat bacterial infections since 1961. Until the introduction of ampicillin by the British company Beecham, penicillin therapies had only been effective against Gram-positive organisms such as staphylococci and streptococci...
) in combination with an aminoglycoside
Aminoglycoside
An aminoglycoside is a molecule or a portion of a molecule composed of amino-modifiedsugars.Several aminoglycosides function as antibiotics that are effective against certain types of bacteria...
(usually gentamicin
Gentamicin
Gentamicin is an aminoglycoside antibiotic, used to treat many types of bacterial infections, particularly those caused by Gram-negative organisms. However, gentamicin is not used for Neisseria gonorrhoeae, Neisseria meningitidis or Legionella pneumophila...
) or a third-generation cephalosporin
Cephalosporin
The cephalosporins are a class of β-lactam antibiotics originally derived from Acremonium, which was previously known as "Cephalosporium".Together with cephamycins they constitute a subgroup of β-lactam antibiotics called cephems.-Medical use:...
(usually cefotaxime
Cefotaxime
Cefotaxime is a third-generation cephalosporin antibiotic. Like other third-generation cephalosporins, it has broad spectrum activity against Gram positive and Gram negative bacteria...
—ceftriaxone
Ceftriaxone
Ceftriaxone is a third-generation cephalosporin antibiotic. Like other third-generation cephalosporins, it has broad spectrum activity against Gram-positive and Gram-negative bacteria. In most cases, it is considered to be equivalent to cefotaxime in terms of safety and efficacy...
is generally avoided in neonates due to the theoretical risk of kernicterus
Kernicterus
Kernicterus is damage to the brain centers of infants caused by increased levels of unconjugated bilirubin. This may be due to several underlying pathologic processes. Newborn babies are often polycythemic. When they break down the erythrocytes, one of the byproducts is bilirubin, which circulates...
.) The organisms which are targeted are species that predominate in the female genitourinary tract and to which neonates are especially vulnerable to, specifically Group B Streptococcus
Group B Streptococcus
Infection with Group B Streptococcus , also known as 'Streptococcus agalactiae' and more colloquially as Strep B and group B Strep, can cause serious illness and sometimes death, especially in newborn infants, the elderly, and patients with compromised immune systems...
, Escherichia coli
Escherichia coli
Escherichia coli is a Gram-negative, rod-shaped bacterium that is commonly found in the lower intestine of warm-blooded organisms . Most E. coli strains are harmless, but some serotypes can cause serious food poisoning in humans, and are occasionally responsible for product recalls...
, and Listeria monocytogenes (This is the main rationale for using ampicillin versus other beta-lactams.) Of course, neonates are also vulnerable to other common pathogens that can cause meningitis
Meningitis
Meningitis is inflammation of the protective membranes covering the brain and spinal cord, known collectively as the meninges. The inflammation may be caused by infection with viruses, bacteria, or other microorganisms, and less commonly by certain drugs...
and bacteremia
Bacteremia
Bacteremia is the presence of bacteria in the blood. The blood is normally a sterile environment, so the detection of bacteria in the blood is always abnormal....
such as Streptococcus pneumoniae
Streptococcus pneumoniae
Streptococcus pneumoniae, or pneumococcus, is Gram-positive, alpha-hemolytic, aerotolerant anaerobic member of the genus Streptococcus. A significant human pathogenic bacterium, S...
and Neisseria meningitidis
Neisseria meningitidis
Neisseria meningitidis, often referred to as meningococcus, is a bacterium that can cause meningitis and other forms of meningococcal disease such as meningococcemia, a life threatening sepsis. N. meningitidis is a major cause of morbidity and mortality during childhood in industrialized countries...
. Although uncommon, if anaerobic species are suspected (such as in cases where necrotizing enterocolitis
Necrotizing enterocolitis
Necrotizing enterocolitis is a medical condition primarily seen in premature infants, where portions of the bowel undergo necrosis .-Signs and symptoms:...
or intestinal perforation is a concern, clindamycin
Clindamycin
Clindamycin rINN is a lincosamide antibiotic. It is usually used to treat infections with anaerobic bacteria but can also be used to treat some protozoal diseases, such as malaria...
is often added.
Granulocyte-macrophage colony stimulating factor (GM-CSF) is often used in neonatal sepsis, however a recent study found that, while GM-CSF corrects neutropenia if present, it has no effect on reducing sepsis or improving survival.