Infection Flashcards
Why are newborn infants more vulnerable to infections compared to older children?
Newborn infants are more vulnerable to infections due to their immature immune systems, which are not yet fully developed to effectively fight off pathogens.
How can newborn infants acquire infections?
Newborn infants can acquire infections from various sources, including the mother during pregnancy, labor, delivery, or breastfeeding. Infections can also be acquired from the nursery or home environment after birth, through exposure to pathogens.
Why are preterm infants more prone to serious complications from infections?
Preterm infants are more vulnerable to serious complications from infections due to their immature immune systems and underdeveloped organs, which may not be able to cope with the effects of the infection as effectively as those of full-term infants.
Defense Mechanism: specific antibodies
- humoral antibodies
- cell mediated immunity
- inflammatory reaction
Defense Mechanism: General factors
- antenatal
- postnatal
- nursery care
Which type of antibody is transferred across the placenta, especially in the last trimester, to protect the infant against specific infections?
IgG antibodies are transferred across the placenta, especially in the last trimester of pregnancy. This passive immunity protects the infant, particularly the term infant, against specific infections to which the mother has been immunized.
How long does passive immunity provided by IgG antibodies transferred across the placenta typically last in infants?
Passive immunity provided by IgG antibodies transferred across the placenta typically wanes after four to six months of age. However, in some cases, it may persist up to 9 months, as seen with infections like measles.
Do IgM and IgA antibodies cross the placenta?
No, neither IgM nor IgA antibodies cross the placenta. These antibodies are normally only produced by the infant after birth.
Under what circumstances can a fetus produce IgM antibodies?
The fetus can produce IgM antibodies in response to an intrauterine infection, such as congenital syphilis.
Why is cell-mediated immunity compromised in newborn infants?
Cell-mediated immunity is compromised in newborn infants because their lymphocytes have not yet been exposed to antigens, and thus do not function effectively.
How does the inflammatory response differ in newborns compared to older individuals?
In newborns, the inflammatory response is poor. Phagocytosis of bacteria by leukocytes is inefficient due to reduced opsonins (such as complement) and delayed chemotaxis.
Why are newborn infants, especially preterm infants, at high risk of infections?
Newborn infants, especially preterm infants, are at high risk of infections due to their immature and inexperienced immune system. The compromised inflammatory response and inefficient phagocytosis increase susceptibility to infections.
Which organisms can pass through the placenta during pregnancy, despite its filtering function?
While the placenta filters out most organisms, some can still pass through, including the Rubella virus, HIV, Toxoplasma, CMV (Cytomegalovirus), and Treponema pallidum (syphilis).
What substances are present in amniotic fluid to reduce the risk of bacterial infection?
Amniotic fluid contains lysozymes and other antibacterial agents. These substances help to reduce the risk of bacterial infection in the prenatal environment.
What components in breast milk help protect infants against infections?
Breast milk contains various components such as IgG, IgM, IgA, lymphocytes, macrophages, and lysozymes. Lactoferrin and transferrin present in breast milk specifically protect against Gram-negative organisms.
How does breastfeeding influence the microbiota in infants?
Breastfeeding promotes the growth of beneficial bacteria like Lactobacilli while inhibiting the growth of harmful bacteria like E. coli, contributing to a healthier gut microbiota in infants.
What measures can be taken in nursery care to prevent infections?
In nursery care, infection prevention can be achieved through practices such as hand-washing, good skin, cord, and eye care. Kangaroo mother care (KMC) also helps by colonizing the infant with maternal flora, while hand-washing, breast milk feeding, and KMC combined can effectively prevent many cases of nosocomial infection in the nursery.
What are the sources of infections during the antenatal period?
Infections during the antenatal period can occur via transplacental spread, involving organisms such as syphilis, HIV, Rubella, CMV, and Varicella. Additionally, ascending spread from the cervix can cause bacterial chorioamnionitis.
Which infections can be transmitted during the intrapartum period?
During labor and delivery, infections such as HIV, Herpes, Group B Streptococci, Gonococci, Candida, Chlamydia, and Hepatitis B pose a risk, with increased risk associated with prolonged labor.
What are the sources of infections in the postnatal period?
In the postnatal period, infections can occur through cross-infection via contaminated hands, feeds, or inhalation. Additionally, unsterile procedures, intubation, and the presence of long lines can contribute to the spread of infections. Breast milk can transmit HIV and CMV.
What infection can be acquired through contact at home?
What infection can be acquired through contact at home?
What is the definition of congenital infection?
Congenital infection refers to the infection of the fetus at any time during pregnancy, excluding the last 5 days before birth, which is considered perinatal infection.
What does the acronym TORCHES stand for in the context of congenital infections?
The acronym TORCHES stands for Toxoplasmosis, Other (including TB, malaria, listeriosis, etc.), Rubella, Cytomegalovirus, Herpes simplex virus, and Syphilis. It serves as a mnemonic to remind healthcare providers of potential causes of congenital infections. However, it’s worth noting that some of these organisms, like herpes, rarely cause true congenital infections, while others may be geographically concentrated, such as toxoplasmosis.
What are some clinical features commonly observed in infants with congenital infection
Infants with congenital infection often present with widespread disease as the organisms typically enter the bloodstream via the umbilical vessels. Clinically obvious features may include growth restriction, hepatosplenomegaly (HSM), pneumonitis, petechiae, jaundice (conjugated), or microcephaly.
How can the placenta assist in diagnosing congenital infection?
The placenta is usually infected in cases of congenital infection and can serve as a valuable organ for determining the diagnosis. Examination of the placenta can provide important clues and help confirm the presence of infection, aiding in the diagnosis and management of the condition.
How should syphilis screening be conducted in pregnant women?
All pregnant women should be screened for syphilis at their booking visit using a TPHA (Treponema Pallidum Haemagglutination Assay). If the TPHA is positive, a VDRL (Venereal Disease Research Laboratory) or RPR (Rapid Plasma Reagin) test should be performed to distinguish present from past infection.
What diagnostic criteria suggest a high likelihood of syphilis infection during pregnancy?
A VDRL or RPR titre of 1:16 or above is highly suggestive of syphilis infection during pregnancy.
What are the potential effects of syphilis on pregnancy
Syphilis can affect the placenta and fetus, leading to adverse outcomes such as first-trimester abortion, stillbirth, clinically infected infant at birth, or delayed onset of syphilis signs in apparently normal infants.
Treatment of syphilis
Infected mothers should receive treatment with 2.4 million units of benzathine penicillin intramuscularly every week for three weeks to prevent transmission to the fetus and improve maternal health.
Clinical signs of syphilis
- Heavy, pale placenta.
- Rash including on palms and soles. May be peeling.
- Hepatosplenomegaly (90%).
- Jaundice (conjugated), pallor or purpura.
- Oedema.
- Respiratory distress due to syphilitic pneumonia.
- X-ray examination of the long bones may show metaphysitis, especially around
the knee. - The infant’s TPHA and VDRL/RPR is positive, whether infected or not, as the
maternal antibodies cross the placenta. If the infant titre is higher than the
maternal titre this suggests infection.
What is the recommended treatment for infants presenting with clinical signs of syphilis?
Infants with clinical signs of syphilis should be treated with penicillin G, administered intravenously at a dose of 100,000 units every 12 hours for a duration of 10 days.