Paed:Neonates Flashcards
How does the heart adapt to ex-utero life?
- closure of foetal shunts
- perfusion of lungs
- decrease in pulmonary artery pressure
- increase in systemic BP
- increase in CO
- foetal lung fluid removed
How does the resp system adapt to ex-utero life?
- lungs filled with air
- surfactant released
- gas exchange
What is the implantation phase?
Weeks 1-2 following missed period
What is the embryo stage?
up to 8-9 weeks (by end of this stage you are fully formed)
What is the foetus stage?
from 12-16 weeks movements felt by mother, all systems present + functioning to varying degrees, lasts 4-6 weeks and is mainly all growth (mostly fat.)
What are the low birth weight categories?
Very low: <1500g
Extremely low: <1000g
Incredibly low: <750g
What are the infant benefits of breast feeding?
less infection, decreased gastroreflux, less immune drives/alergic disease, decreased risk of : NEC, SIDS, inguinal hernia, higher IQ
What are the maternal benefits of breast feeding?
Reduces cancer: breast, uterine, ovarian, endometrial
Improved health: less PPH, depression, osteoporosis
Promotes postpartum weight loss
Delays fertility
Less medical + food expense
How do premature babies feed and why?
IV fluids/parental nutrition because they cannot yet suckle
What is necrotising enterocolitis (NEC)?
A bacteria invasion of ischaemic bowel wall, usually preterm infants who are fed cow’s milk formula.
What are the clinical signs of NEC?
Stops tolerating feeds, bile-stained vomiting, distended abdomen + pain, stools with fresh blood, shock
What would you see on X-ray for NEC?
Distended loops of bowel + thickening of bowel wall with intramural gas + may be gas in portal tract.
What is the treatment of NEC?
Stop oral feeding Broad spec Abs Parenteral nutrition Artificial ventilation + circulatory support Surgery if perforated bowel
Complications of NEC
Bowel perforation
Strictures
Malabsorption
What is retinopathy of prematurity?
What causes it?
What to do if there are high risk changes?
Arrest of normal vascular growth of the developing blood vessels at the junction of the vascular + non-vascularised retina. Vascular proliferation > retinal detachment, fibrosis + blindness.
Caused by hyperopic insult.
Laser therapy for high risk changes.
Why do >50% of all newborn infants become jaundiced?
- marked physiological release of Hb from RBC breakdown because of high Hb conc at birth
- red cell life Spain of newborn infants is 70 days compared to 120 in adults
- hepatic bilirubin metabolism is less efficient in first few days of life
Why is neonatal jaundice important?
May be a sign of another disorder (e.g. infection, liver disease or haemolytic anaemia.)
Unconjugated bilirubin can deposit in basal ganglia and cause kernicterus.
Causes of unconjugated bilirubin?
Haemolysis, prematurity, sepsis, dehydration, hypothyroid, metabolic disease
What can high levels of unconjugated bilirubin cause? Explain it
Kernicterus
- encephalopathy due to deposition of unconjugated bilirubin in basal ganglia + brainstem nuclei .
- there is excess albumin-binding capacity so it passes by itself through BBB
Where does unconjugaed bilirubin deposit?
Basal ganglia + brainstem nuclei
How does kernicterus present?
Lethargy, poor feeding, irritability, increased muscle tone (opsithotonos), seizures and coma
What may develop after kernicterus?
LD sensorineural deafness, cerebral palsy
How do you treat kernicterus?
- Phototherapy (blue light, 450nm) which converts unconjugated bilirubin into harmless, was-soluble pigment that is excreted in the urine.
- Exchange transfusion (remove blood + replace with donor)
What causes high levels of conjugated bilirubin?
Prolonged parenteral nutrition, NEC, sepsis
high levels not a worry
What bilirubin measurement is classified as clinically jaundiced?
80umol/L
What is respiratory distress syndrome? (RDS)
Deficiency of surfactant which lowers surface tension. This leads to widespread alveolar collapse and inadequate gas exchange.
Where is surfactant retained?
In type 2 pneumocytes of alveolar epithelium
When do alveoli start increasing in number?
From 24 weeks (therefore RDS common in premature babies born before 28 weeks)
What are clinical signs of RDS?
Tachypnoea >60b/m
Laboured breathing with chest wall recession + nasal flaring
Expiratory grunting
Cyanosis
Why is there expiratory grunting in rds?
to create positive airway pressure + maintain functional residual capacity
What is seen on CXR in RDS?
- diffuse granular or ‘ground glass’ appearance of lungs + air on bronchogram
- indistinct heart border
- tracheal tube + umbilical artery catheter present
What is the treatment for RDS?
Surfactant therapy
Raised ambient O2 (CPAP via nasal cannula) or artificial ventilation via tracheal tube
What are the complications of RDS?
Pulmonary interstitial emphysema (PIE)
> if air from over distended alveoli track into the interstitium
Pneumothorax
What is chronic lung disease of prematurity?
Officially needing O2 at 36 weeks corrected age
- reduced lung volume
- reduced alveolar surface are
- diffusion defect
Increase mortatiliy and recurrent admissions
What is apnoea of prematurity?
Baby ‘forgets’ to breathe because the brainstem is not fully myelinated until 32-34 weeks.
Often accompanied by bradycardia if they stop breathing for 20-30secs or if breathing continues against a closed glottis.
How do you treat apnoea of prematurity?
Gentle physical stimulation
NCPAP
Caffeine
Where does a haemorrhage usually occur?
Germinal matrix above the caudate nucleus
What are the risk factors for a haemorrhage?
Perinatal asphyxia, RDS, pneumothorax
What is oesophageal atresia usually assoc with?
Polyhramnios during pregnancy
Tracheo-oesphageal fistula
What is the clinical presentation of oesophageal atresia?
Persistent salivation Drooling from mouth after birth Cough + choke on feeds Cyanotic episodes Aspiration of saliva/milk into lungs
How is oesophageal atresia diagnosed (if not at birth)?
Pass a wide-calibre feeding tube to see if it reaches stomach (checked on X-ray)
What other congenital malformations do babies with oseophgeal atresia often have?
Vertebral Anorectal Cardiac Tracheo-o Eoesophageal Renal + radial Limb (radial limb)
What causes small bowel obstruction?
- Atresia or stenosis of duodenum (1/3rd have Down’s: ‘double bubble’)
- atresia or stenosis of jejunum or ileum
- malrotatino with volvulus
- meconium ileum
- meconium plug
What is the complication of malrotation with volvulus?
Infarction of entire midgut
What are the symptoms of small bowel obstruction?
Persistent, bile-stained vomiting
Abdominal distension
How do you investigate and treat SBO?
Abdo x-ray
Surgical
Dislodge meconium ileum with gastrografin contrast medium (laparotomy needed)
What can cause large bowel obstruction?
Hirschprung disease
What is gastroschsis?
When the bowel protrudes through a defect in the anterior abdominal wall, adjacent to umbilicus
- bowel exposed with no sac
- less congenital anomalies
- reduce surgically or silo (wrap sling film to reduce risk of dehydration and protein loss and heat loss)
What is exomphalos?
Abdo content protrude through umbilical ring, covered with a transparent sac formed by amniotic membrane and peritoneum.
More congenital anomalies. (e.g. Beckwith Wide Mann)
Can be so big they are inoperable
What can cause meconium aspiration?
Hypoxia can result in meconium passage in utero and associated gasping leads to aspiration.
What are the consequences of meconium aspiration?
inhibits surfactant, obstructs resp tract and induced pneumonitis
How does meconium aspiration present?
Respiratory distress soon after birth
What is seen on CXR for meconium aspiration?
Generalised overinflation with patchy collapse/consolidation +/- air leaks
How can meconium aspiration be prevented?
If liquor is meconium-stained: delivery should be expedited to prevent further hypoxia and gasping
Apnoeic baby at birth: suck out meconium from larynx/trachea using bore suction tube
How do you treat meconium aspiration?
O2, surfactant, Abx
What is hypoxic-ischaemic encephalopathy?
Results from perinatal cerebral hypoxia
What causes hypoxic-ischaemic encephalopathy?
- Decreased umbilical blood flow (eg. cord prolapse)
- Decreased placental gas exchange (e.g. placental abruption)
- Decreased maternal placental perfusion
- Maternal hypoxia
- Inadequate postnatal cardiopulmonary circulation
How does hypoxic-ischaemic encephalopathy present?
Depends on grade but affects:
- LOC, muscle tone, posture, reflexes, suck, moro, autonomic dysfunction, heart rate and seizures
How is hypoxic-ischaemic encephalopathy managed?
Resuscitate at birth, exclude other causes
What complications can hypoxic-ischaemic encephalopathy cause in the future?
Spastic quadriplegia Dyskinetic cerebral palsy Severely reduced IQ Cortical blindess Hearing loss Epilepsy
What is bronchopulmonary dysplasia? (BPD)
Persistent respiratory distress usually after prolonged intubation with high o2 conc.
What are the clinical features of BPD?
Hypoxamiea, hypercapnia, apnea, bradycardia, congestive heart failure
How do you treat BPD?
Gradual warning from ventilator, feed and grow, dexamethasone to decrease inflammation and help weaning
When should intrapartum IV penicllin or clindamycin be offered to women?
- previous baby with neonatal GBS disease
- GBS bacteria in current pregnancy
GBS sx
What could indicate group b strep infection?
- intrapartum fever >38
- preterm
- PROM >18hr
- GBS maternal carriage detected on vaginal swab culture
What are the TORCH infections?
Toxoplasmosis Other: syphilis, varicella-zoster, parvovirus Rubella CMV Herpes simplex
What are the clinical features of torch infections?
- SGA, jaundice, hepatitis, hepatosplenomegaly, pupura, hydrocephalus
Rubella + CMV: deafness, cataracts, congenital heart disease
Parvo: rubella-like rash, haemolytic anaemia +/- hydrops
What is bowel atresia?
A birth defect affecting a part of the small intestine (the tube that connects stomach to intestine to digest food)
What can cause bowel atresia?
Inadequate blood supply to baby’s intestine during fetal development.
What is assoc with small bowel atresia?
Polyhydramnios - may be suggested during pregnancy from USS
How can small bowel atresia be diagnosed?
Clinically identified from sx such as vomiting, green bile and swollen abdo indicating need for Xray or contrast scan. Always requires surgical treatment.
What is the most common cause of viral encephalitis in children?
Herpes simplex encephalitis
How is HSV transmitted?
During delivery through an infected maternal genital tract
Symptoms of HSV
Skin or mucosal vesicles
CNS disease
Neonates with disseminated disease and visceral organ involvement have hepatitis, pneumonitis, disseminated intravascular coagulation, or a combination, with or without encephalitis or skin disease.
Other signs, which can occur singly or in combination, include temperature instability, lethargy, hypotonia, respiratory distress, apnea, and seizures.
How is HSV diagnosed?
HSV culture or PCR
Treatment of HSV?
Parenteral acyclovir + supportive therapy
How do orofacial clefts happen?
failure of fusion of maxillary and premaxillary processes.
Causes of orofacial clefts?
Genetic, associated syndromes eg Pierre-Robin syndrome
maternal medications: phenytoin
Treatment of orofacial clefts?
Surgical repair lip at 3 months
Repair palate at 6-12 months
Dental plate used if cleft palate too large to allow adewuate suck/feeding
Complications of cleft?
Secretory otitis media Speech defect Hindered parentaral bonding Aspiration pneumonia Psychological morbidity
