Neonatology Flashcards
Need to do congenital heart disease LOs
Congenital heart disease
What are the clinical features of neonatal sepsis?
Fever or temperature instability or hypothermia Poor feeding Vomiting Apnoea and bradycardia Respiratory distress Abdominal distention Jaundice Neutropenia Hypoglycaemia/hyperglycaemia Shock Irritability Seizures Lethargy, drowsiness
How are early and late onset sepsis defined?
Early onset (<48 hours )Late onset (>48 hours)
What are the risk factors for neonatal sepsis?
In colonised mothers the risk factors are:
- preterm
- prolonged rupture of the membranes
- maternal fever during labour
- maternal chromioamnionitis
- previously infected infant
How common is group B strep?
10-30% of pregnant women have faecal or vaginal carriage of group B strep
Organism causes early and late onset sepsis
- Early - it can causes pneumonia, may also cause septicaemia, and meningitis
- Late - presents with meningitis or occasionally focal infection
How is group B strep managed antenatally?
prophylactic intrapartum antibiotics given intravenously to the mother can prevent group B strep infection in the newborn baby
Given if screening has taken place or if there are lots of risk factors
How does early onset sepsis present?
pneumonia, respiratory distress, may causes septicaemia and meningitis
How does late onset sepsis present?
meningitis, usually by 3/12 may see septic arthritis, osteomyelitis
List common viral and bacterial pathogens causing disease in the newborn
group B streptococcal infection
gram-negative infection
herpes simplex virus
hepatitis B
What are the most common viral infections affecting the fetus and newborn
CMV Rubella Toxoplasmosis Parovirus Varicella Zooster Syphilis
What determines the risk and extent of fetal damage in rubella infection
mainly determined by gestational age at the onset of maternal infection
What are the consequences of maternal infection with rubella at 8, 13 and 18 weeks?
infection <8/40 = deafness, CHD, cataracts
13-16/40 deafness in 30%
After 18 weeks minimal risk
What is the most common congenital infection?
CMV
What are the consequences of CMV infection?
90% normal
5% heptosplenomegalty and petechiae at birth, usually neurodevelopmental issues e.g. hearing loss 5% develop propblems later e.g. sensorineural hearing loss
What are the consequences of Toxoplasmosis infection?
10% clinically affected - retinopathy, cerebral calcification, hydrocephalus
Likely to have long term neurodisabilities
What are the consequences of VZV infection?
infection <20/40 small risk of severe scarring, ocular or neurodamage, digital dysplasia infection within 5 days pre/2 days post delivery ~25% have vesicular rash
When does the infant need protection from chickenpox infection?
if mother develops chickenpox shortly before or after delivery
What are the clinical features of congenital syphilis?
specific to congenital syphilis:
characteristic rash on the soles of the feet and hands and bone lesions
What are the consequences of herpes infection in mothers?
localised herpetic lesions on skin or eye or with encephalitis or disseminated disease
How is HIV transmission from mother to baby prevented and managed?
- use of maternal antenatal, perinatal and postnatal antiretroviral drugs to achieve and undetectable maternal viral load at the time of delivery
- avoidance of breast feeding
- active management during labour and delivery –> avoid prolonged rupture of membranes
- pre labour C-section if mothers viral load is detectable close to tie of delivery
What are the differentials for bile stained vomit?
intestinal obstruction until proven otherwise
What are the causes of intestinal obstruction?
small bowel obstruction:
- atresia or stenosis of the duodenum/ileum/jejunum
- malrotation with volvulus
- meconium ileus
- meconium plug
How is early onset sepsis treated?
antibiotics are started immediately without waiting for culture results - stopped after 36/28 hours if negative culture
broad spectrum abx are given that cover gram positive and negative organisms
How is late onset sepsis treated?
most likely acquired flucloxacillin and gentamycin are given as cover most staphylococci and gram-negative organisms if organism resistant that specific abx are given –> vancomycin or broad spectrum abx indicated
What are the risks of prolonged or broad spectrum antibiotics in neonates?
predisposes to invasive fungal infections in premature infants
What are the common investigations used in newborns?
chest xray lumbar puncture CRP FBC Blood cultures
What is IUGR (Intrauterine Growth Restriction)?
Baby fails to reach genetically determined growth potential
What are small for gestational age infants?
Babies following IUGR with birthweight below the 10th centile for their gestational age
What are the causes of growth restriction in babies?
asymmetrical growth restriction:
placental dysfunction secondary to maternal pre-eclampsia, multiple pregnancy, maternal smoking
symmetrical growth restriction: fetal chromosomal disorder or syndrome, a congenital infection, maternal drug or alcohol abuse, chronic medical condition or malnutrition
What is a fetus with IUGR at risk from?
intrauterine hypoxia and ‘unexplained’ intrauterine death asphyxia during labour and delivery
What are potential problems at birth in a growth restricted infant?
hypothermia - because of their relatively large SA
hypoglycaemia from poor fat and glycogen stores
hypocalcaemia polycythaemia in addition: RDS, NEC, ROP
What are the long term complications of IUGR?
increased risk of T2DM, obesity, HTN, dyslipidaemia, insulin resistance (metabolic syndrome) - leads to premature development of CVD
What is respiratory distress syndrome?
deficiency of surfactant which lowers surface tension
What are the consequences of surfactant deficiency?
widespread alveolar collapse and inadequate gas exchange
How common is RDS?
very common in infants before 28 weeks rare at term but may occur in infants with diabetic mothers and very rarely from genetic mutations
How do babies with RDS present at delivery?
tachypnoea over 60 breaths/min
laboured breathing with chest wall recession and nasal flaring
expiatory grunting in order to try to create positive airway pressure during expiration and maintains functional residual capacity cyanosis if severe
How are babies with RDS treated?
raised ambient oxygen is required
surfactant therapy may be given by instilling surfactant directly into the lungs via the tracheal tube or catheter
additional respiratory support with CPAP or high flow nasal cannula oxygen
mechanical ventilation may also be used if needed
What are the problems preterm infants face?
- need for rescusitation and stabilisation
- respiratory - RDS, pneumothorax, apnoea, bradycardia
- hypotension
- patent ductus arteriousus
- temperature control
- metabolic
- hypoglycaemia, hypocalcaemia, electrolyte imbalance, osteopenia of prematurity
- nutrition
- infection
- jaundice
- IVH
- necrotizing enterocoloitis
- retinopathy of prematurity (ROP)
- anaemia of prematurity
- Iatrogenic
- bronchopulmonary dysplasia
- inguinal hernias
How common are pneumothorax is preterm infants?
10% of patients who are ventilated presents with increased work of breathing and chest movement on affected side is reduced
tension pneumothorax are treated with chest drain insertion
What is NEC?
necrotising enterocolitis
bowel of preterm infant is vulnerable ischaemic injury and bacterial invasion are both risk factors less likely to occur if babies are fed breast milk
What are the signs of NEC?
feed intolerance and vomiting (may be bile stained)
distended abdomen
pain
stool stained with fresh blood
infant may become shocked and require mechanical ventilation because of ado distension and pain
What are the characteristic signs of NEC on an X-ray?
distended loops of bowel
thickening of the bowel wall with intramural gas may be gas in portal venous tract
What are the consequences of NEC?
bowel may perforate
20% mortality
What is the treatment for NEC?
stop oral feeding
give oral antibiotics to cover both aerobic and anaerobic organisms
parenteral nutrition is required
mechanical ventical
surgery is performed for bowel perforation
Why are preterms at increased risk of infection?
IgG is transferred across the placenta in the last trimester and no IgA or IgM is transferred
Infection at cervix is often a reason for preterm labour and may cause infection shortly after birth
What are the consequences of hypothermia in a preterm baby?
- increased energy consumption and may result in hypoxia and hypoglycaemia
- failure to gain weight
- increased mortality
Why are preterm infants particularly vulnerable to hypothermia?
- large SA relative to their mass, so there is greater heat loss than heat generation
- skin is thin and heat permeable, so transepidermal water loss is important in the first week of life
- little subcutaneous fat for insulation in the first week of life
- they are often nursed naked and cannot conserve heat by curling up or generate heat by shivering
How are is the temperature managed in preterm babies?
incubators which proved overhead radiant heaters and allow ambient humidity to be maintained which reduces transepidermal heat loss
Why are episodes of apnoea/bradycardia and desturation common in very low birth weight infants?
- Common until 32 weeks gestation as immature central respiratory control
- May occur when infant stops breathing for over 20-30 secs or when when breathing continues against a closed glottis
- Must exclude an underlying cause (hypoxia, infection, anaemia etc)