Neonatology 4 Flashcards
What is rhesus haemolytic disease. affect on baby
condition where antibodies in a pregnant woman’s blood destroy her baby’s blood cells
also known as haemolytic disease of the foetus and newborn (HDFN)
Baby may become anaemic and jaundiced.
Hydrops, hepatosplenomegaly and rapid jaundice are rare nowadays due to antenatal care
When can ABO incompability occur
Most ABO antibodies are IgM and do not cross the placenta.
Some group O women have an IgG anti-A haemolysin in the blood - it can cross placenta and haemolyse group A infant RBCs
(occasionally there is a group B infant affected by anti-B haemolysis)
Effects of ABO incompability (haemolysis)
Severe jaundice
Peak 12-72 hrs
Hb level usually normal
NO hepatosplenomegaly (in contrast to Rhesus)
Diagnosis of Rhesus/ABO haemolysis
Bloods:
biochemistry for jaundice
antibody screen
Treatment of ABO/Rhesus incompability
Before birth: intrauterine transfusion (RBCs) or early induction of labour once there is pulmonary maturity
Mother can undergo plasma exchange to lower circulatory antibodies by 75% .
Anti-D prophylaxis after first Rhesus +ve child in a Rhesus -ve mother
Treatment of baby may be treatment of jaundice with phototherapy.
Transfusion with RBC may be needed
Bicarbonate for acidosis
Most complications arise from high bilirubin
Important RF for congenital abnormalities
Large number are due to genetic conditions.
There are a huge number.
Maternal and paternal age.
Infections (TORCH - toxoplasmosis, others, rubella, CMV and HSV)
Toxins (alcohol, smoking, mercury, prescription drugs)
Dietary deficiencies eg. folic
What is CHARGE?
Acronym that describes a set of unusual congenital features seen in many newborn children.
Coloboma (hole in one of the eye structures - retina, choroid, iris, optic disc) Heart defects Atresia of the nasal choanase Retarded growth and development Genitourinary abnormalities Ear abnormalities and hearing loss
Leading cause of congenital deafness. Very few people will have all features
Genetics of CHARGE
Autosomal dominant
Chromosome affeced is 8q12 and gene CHD7
What is VACTERAL
Acronym that describes a syndrome/associated of birth defects
Vertebral (hypoplastic vertebrae(scoliosis)
Anal atresia
Cardiac defects (ASD, VSD, tetralogy of Fallot)
Tracheo-oesophagel fistula
Esophageal atresia
Renal abnormalities (eg 1 umbilival vein causing outflow obstruction)
Limb defects (hypoplastic thumbs, extra digits, fusion)
What is VACTERAL associated with
trisomy 18
Diabetic mothers
Most babies have normal development and intelligence, but can be quite small
What is Patau syndrome
trisomy 13
Most are detected on 2nd trimester scan
Structural defect of brain Scalp defects Small eyes (microphthalmia) Cleft lip and palate Polydactyly Cardiac and renal malformations
What is Edward syndrome
Trisomy 18
Most detected on antenatal scan
Low birthweight Prominent occiput Small mouth+chin Short sternum Flexed overlapping fingers Rocker-bottom feet Cardiac and renal malformation
Pathology of cleft lip/palate
Unilateral or bilateral
Failure of fusion of the frontonasal and maxillary processes
Some associated with maternal anticonvulsant therapy
Clinical features of fetal alcohol syndrome
Growth restriction
Characteristic facies
Developmental delay
70% have cardiac defects
What is neural tube defects
result from failure of normal fusion of the neural plate to form the neural tube during the first 28 days following conception
Folic acid supplementation reduces risk
Different types of neural tube defect
Anencephaly Encephalocoele Spina bifida occulta Meningocoele Myelomeningoceles
What is anencephaly
Failure of development of most of the cranium and brain
Affected infants stillborn or die shortly after birth
Detected on antenatal screening with TOP
What is encephalocele
Extrusion of brain and meninges through a midline skull defect which can be corrected surgically
However, often there are associated cerebral malformations
What is spina bifida occulta
Failure of fusion of vertebral arch.
There may be an associated skin lesion in the lumbar region - tuft of hair, lipoma, birthmark
May be underlying tethering of the cords: cause neurological deficits of bladder function and lower limbs
What are myelomeningoceles associated with
variable paralysis of the legs
Muscle imbalance which can cause dislocation of hips
Sensory loss
Bladder denervation (neuropathic bladder)
Bowel denervation (neuropathic bowel)
Scoliosis
Hydrocephalus
Features of gastroschisis
Defect in anterior abdominal wall through which the abdominal contents freely protrude
No overlying sac or peritoneum
Size of defect usually <4cm
Features of exomphalos
Weakness of abdominal wall where the umbilical cord joins it
Allows abdominal contents (mainly bowel and liver) to protrude outside the abdominal cavity where they are contained in a loose sac
What is bowel atresia
Narrowing or absence of a portion of the intestine
Can occur in either small or large intestine
Recognize biliary tree atresia from history and investigations
Normal birthweight but FTT as disease progresses
Mild jaundice with pale stools and dark urine
Hepatosplenomegaly often present
LFTs are of little value
Fasting USS may show contracted/absent gallbladder
Radioisotope scan with TIBIDA shows good uptake in the lvier, but no excretion into bowel
Liver biopsy may show features of extrahepatic biliary obstruction
Treatment - surgical bypass of fibrotic ducts (hepatoportoenterostomy aka Kasa procedure)
Main causes of haemolytic disease of the newborn
Immune - haemolytic disease of the newborn
Red cell membrane disorders - hereditary spherocytosis
Red cell enzyme disorders - G6PD deficiency
Haemoglobinopathies - alpha thalassaemia major
Which events can potentially sensitise a Rhesus -ve mothers to a rhesus +ve child?
When mother is sensitised to fetal RBCs:
Fetal-maternal haemorrhage:
- Abortion
- Childbirth
- rupture in placenta during pregnancy
- medical procedures in pregnancy that breach the uterine wall
When mother receives blood transfusion.. although ABO and Rh typing is routine
Mothers with type O blood are more prone to make IgG anti-A and anti-B antibodies which can cross the placenta
FBC results in haemolytic anaemia. Other tests?
Increased reticulocyte count to compensate for anaemia
Increased unconjugated bilirubin
other diagnostic clue is positive direct anti-globulin test (Coombs test): only positive in antibody-mediated anaemias (can differentiate from other causes of haemolytic anaemia)
What is perinatal asphyxia
Gas exchange (pulmonary or placental) is compromised or ceases altogether. Results in cardiorespiratory depression. Causes hypoxia, hypercapnia and metabolic acidosis
Compromised cardiac output diminishes tissue perfusion causing hypoxic-ischaemic injury
Aetiology of HIE (hypoxic ischaemic encephalopathy)
Most follow a significant hypoxic event immediately before or during labour or delivery:
Reduced umbilical blood flow - cord compression including cord prolapse and shoulder dystocia
Reduced placental gas exchange - placental abruption, excessive/prolonged uterine contractions, ruptured uterus
Reduced maternal placental perfusion - IUGR
Maternal hypoxia
Compromised fetus (IUGR or anaemia)
Inadequate postnatal cardiopulmonary circulation - failure to breath
Presentation of hypoxic ischaemic encephalopathy
Varies depending on severity of cerebral hypoxia
Level of consciousness Muscle tone Posture Tendon reflexes Suck Heart rate CNS homeostasis
Start <48hrs after asphyxia.
Mild: infant is irritable, responds excessively to stimulation, may have staring of eyes and hyperventilation and has impaired feeding
Moderate - infant shows marked abnormalities of tone and movement, cannot feed and may have seizures
Severe - there are no normal spontaneous movements or response to pain, tone in limbs may fluctuate between hypo & hypertonia, seizures are prolonged and often refractory to treatment and multi-organ failure is present
Management of Hypoxic Ischaemic Encephalopathy
Respiratory support
Record amplitude-integrated EEG to detect abnormal background activity to confirm early encephalopathy or identify seizures
Treat clinical seizures with anti-convulsants
Treat hypotension by volume and inotrope support
Monitor and treat hypoglycaemia and electrolyte imbalance, especially hypocalcaemia
THERAPEUTIC HYPOTHERMIA
Explain therapeutic hypothermia
If A and B are met, then assess for C.
A. >36/40. >1800g. <6hr old with:
- Apgar<5 or continued need for resuscitation at 10 min
- acidosis - cord pH<7/BE
Long-term neurodevelopmental risks of HIE
mild - complete recovery
Moderate - if feeding by 2 weeks, prognosis is excellent. If clinical abnormalities persist, full recovery unlikely
Severe - mortality of 30-40%. 80% survivors have neurodevelopmental disabilities, particularly CP.
If MRI at 4-14 days shows significant brain abnormalities, the risk of CP is very high
Effects of multi-orgn dysfunction in HIE
Encephalopathy:
seizures, abnormal signs
Resp:
Persistent pulmonary HTN of the newborn (PPHN)
Myocardial:
Hypotension
Metabolic:
hypoglycaemia
hypocalcaemia
hyponatraemia
Other:
renal failure
DIC
