Neonates

Question 1

Effects of warfarin on the foetus during pregnancy

Answer 1

• Hypoplastic nasal bridge - Chondrodysplasia - CNS malformations - Increased risk of bleeding

Question 2

Effects of sodium valproate on the foetus during pregnancy

Answer 2

Neural tube defects

Question 3

Types of open neural tube defects (spina bifida aperta)

Answer 3

SPINAL - Meningocele; vertebrae fail to fuse and a fluid filled sac is pushed through the defect. Sac contains fluid NO nerves - Myelomeningocele (most common); sac contains fluid + spinal cord CRANIAL - Anencephaly - Encephalocele

Question 4

Types of closed neural tube defects (spina bifida occulta)

Answer 4

• Lipomyelomeingocele - Lipomeningocele

Question 5

Klumpke palsy

Answer 5

• Brachial plexus injury at the level of C8/T1 - Weakness of the intrinsic muscles of the hand, forearm flexors and forearm pronators. - “Claw hand” and supination of the forearm.

Question 6

Erb’s palsy

Answer 6

• Brachial plexus injury at the level of the C5/C6 nerve (upper trunk) but can be more extensive. - “Waiter’s tip” due to loss of elbow flexion and supination (and also wrist extension).

Question 7

Congenital zika features

Answer 7

• Can affect the developing brain - May present with abnormal neurology including seizures + spasticity - Feeding difficulties - Developmental delay - Contractures of the limbs - Microcephaly + intracranial calcifications - Visual abnormalities DOES NOT cause hepatomegaly

Question 8

Benign familial neonatal epilepsy

Answer 8

• Seizures usually present within the first few days of life (fifth day fits) and are brief but can be fairly frequent. - There may be a family history in of seizures in the neonatal/infantile period which self-resolved. - KCNQ2 is a gene that encodes for a potassium channel. Mutations in KCNQ2 are the most common known cause of BFNE. - Children with mutations in KCNQ2, however may also present with an epileptic encephalopathy, i.e. it is not only associated with benign focal seizures but can cause a spectrum of presentations.

Question 9

SCN1A mutation

Answer 9

• SCN1A is a gene that provides instructions to make sodium channels. - Associated with Dravet syndrome (myoclonic epilepsy of infancy) which present with long, often hemiclonic, fever-related seizures during the first year of life later evolving to afebrile seizures with developmental difficulties in the toddler years.

Question 10

DEPDC5 mutation

Answer 10

• DEPDC5 is a gene which is responsible for modulating the mTOR pathway. - Results in a familial focal epilepsy, often associated with focal cortical dysplasia.

Question 11

MECP2 mutation

Answer 11

• Mutations in MECP2 are associated with Rett syndrome (girls presents with developmental delays, repetitive movements of the hands and seizures). - There is also an MECP2 duplication syndrome which presents with severe intellectual disability and hypotonia.

Question 12

Clinical features of congenital CMV

Answer 12

90% asymptomatic 10% will have symptoms; - SGA - Hepatosplenomegaly - Petechiae and purpura of the skin - Jaundice at birth - Least 2/3 have neurological involvement - microcephaly, seizures, feeding difficulties chorioretinitis, retinal scars, optic atrophy, central vision loss - Rhromobocytopaenia, haemolytic anaemia, elevated transaminases, elevated direct and indirect bilirubin - Sensorineural hearing loss >2/3 of newborns with symptomatic congenital CMV infections, almost always progressive to severe or profound hearing loss

Question 13

Clinical features of hypermagnesaemia in neonates

Answer 13

Hypermagnesaemia is not uncommon in neonates where magnesium sulphate has been used in labour. - CNS depression featuring lethargy, hypotonia, hyporeflexia, poor feeding - Respiratory depression. - Delayed passage of meconium Management is generally supportive, such as ventilatory support, however in extreme cases IV calcium and diuresis can be used to reduce serum magnesium levels.

Question 14

Alagille Syndrome

Answer 14

Alagille Syndrome (arteriohepatic dysplasia) is the most common syndrome with intrahepatic bile duct paucity. Facial characteristics: broad forehead, deep set /widely spaced eyes, long straight nose, underdeveloped mandible. Ocular abnormalities: posterior embryotoxon. Cardiac Abnormalities: Usually peripheral PS, sometimes Tetralogy of Fallot. Vertebral arch defects: butterfly vertebrae. Tubulointerstitial nephropathy. Prolonged survival but can suffer significant morbidity from Neuro effects of Vit E deficiency.

Question 15

Rhesus negative mother, risk of Rh sensitisation after delivery of 1st child

Answer 15

16% if Rh+ fetus and mother are ABO compatible 2% if Rh+ fetus and mother are ABO incompatible 2-5% after an abortion

Question 16

Isoimmune haemolytic disease: is rhesus of ABO disease more common?

Answer 16

Haemolytic disease of newborn: rhesus disease is more common than ABO disease 15% of pregnancies are ABO incompatible but only 3% result in ABO disease However, if mother and fetus are rhesus incompatible: additional ABO incompitability decreases the risk of maternal sensitisation to Rh and therefore decreases risk of haemolytic disease of newborn in subsequent pregnancies. this is because maternal anti-A or anti-B antibodies cause destruction of foetal RBC in maternal circulation before maternal immune system can produce Rh antibodies to Rh antigen on foetal RBCs. Rh- mother can be sensitised to Rh antigens by an Rh+ foetus during previous pregnancy. Antibodies cross the placenta and cause immune destruction of Rh+ red blood cells in foetus.

Question 17

Is beta thalassaemia associated with fetal hydrops?

Answer 17

NOT associated with fetal hydrops as fetal haemoglobin (α2γ2) compensates

Question 18

Five phases of lung development

Answer 18

Embryonic (26 days to 6 weeks gestation) Pseudoglandular (6 to 16 weeks gestation) Canalicular (16-28 weeks gestation) Saccular (28-36 weeks gestation) Alveolar (36 weeks through to infancy)

Question 19

Bronchogenic cysts

Answer 19

Bronchogenic cysts can occur at any point throughout the tracheobronchial tree, but are most commonly located in the mediastinum, especially at the level of the carina. In the proper clinical setting, a CT scan finding of a sharply marginated, non-enhancing, water-density mass is diagnostic of a bronchogenic cyst. (i.e. not air-filled).

Question 20

Congenital lobar emphysema

Answer 20

Characterised by hyperinflation of one or more of the pulmonary lobes. This leads to compression of the remaining lung tissue and herniation of the affected lobe across the anterior mediastinum into the opposite chest, causing displacement of the mediastinum. Therefore any collapse would be in the contralateral lung. - Most frequently identified cause of CLE = obstruction of the developing airway. - The left upper lobe is affected most often. The RLL is only affected in <10% of cases. Affected infants usually are symptomatic in the neonatal period.

Question 21

Congenital pulmonary airway malformation (CPAM)

Answer 21

Result from abnormalities of branching morphogenesis of the lung. They are hamartomatous lesions that are comprised of cystic and adenomatous elements arising from tracheal, bronchial, bronchiolar, or alveolar tissue. Large lesions can compromise alveolar growth and development by compressing adjacent normal tissue. CPAMs have connections with the tracheobronchial tree, although the connecting bronchi are usually not normal. The arterial supply and venous drainage from the lesion are from the pulmonary circulation, though vascular connections to the systemic circulation have been reported.

Question 22

In the fetus with a structurally normal heart. The percentage of pulmonary arterial blood flow that is directed through the ductus arteriosus is

Answer 22

90%

Question 23

Phenylketonuria

Answer 23

Phenylalanine is an essential amino acid. It is catalysed by phenylalanine hydroxylase (PAH), a hepatic enzyme, to tyrosine. Tetrahydrobiopterin (BH4) is a cofactor which aids PAH. Newborn screening detects high levels of phenylalanine before clinical effects can be seen. Early intervention with a strictly reduced phenylalanine diet can prevent sequelae. A: Babies can still breastfeed but it is recommended that 75% of feeds should be phenylalanine-free formula. If mothers wish to breastfeed, they should be supported by an experienced metabolic dietician. B: Phenylalanine reduced diet is a lifelong intervention. A previous RCT showed improved outcomes in children who continued the diet after the age of six years. C: Only 2% of cases of PKU are caused by BH4 deficiency. Most cases of PKU are caused by PAH deficiency. D: PKU is an autosomal recessive disorder caused by multiple different mutations in the gene which codes for PAH.

Question 24

HIV + pregnant women: risk of transmission+ ways to reduce transmission

Answer 24

Pregnant women with HIV infection have a transmission risk (untreated) of approximately 15-30%. Measures to reduce transmission rates to <5% include: Antiretroviral therapy during pregnancy and delivery Antiretroviral therapy during delivery only if unable to administer during pregnancy Elective C-section Avoid invasive fetal procedures Avoid breast-feeding Oral AZT to infant for the first 4-6 weeks The biggest benefit is through antiretrovial therapy during pregnancy.

Question 25

Listeria monocytogenes

Answer 25

During pregnancy women may be completely asymptomatic or have a mild ‘flu like’ illness May result in miscarriage, premature labour, neonatal sepsis or stillbirth. In severe cases, the baby may develop granulomatosis infantiseptica which is characteristic of severe in utero infection. Neonates have multiple abscesses or granulomas in multiple organs and are stillborn or die shortly after birth. Some may develop ulcerative skin lesions. Listeria is easily easily identified with gram stain.

Question 26

Congenital hypothyroidism

Answer 26

Most cases from thyroid dysgenesis – 85% Some cases familial, inborn error of thyroid hormone synthesis – 10% Transplacental maternal thyrotropin receptor blocking antibody – 5% Most infants asymptomatic at birth (some maternal T4 crosses placenta) Clinical features: lethargy, slow movement, hoarse cry, feeding problems, constipation, macroglossia, umbilical hernia, large fontanels, hypotonia, dry skin, hypothermia, prolonged jaundice Associated congenital malformations: affecting heart, kidneys, urinary tract, GI, skeletal In dyshormonogensis – goitre is present Thyroid dysgenesis: 50% aplasia 50% hypoplasia or ectopic gland Unknown cause in most cases

Question 27

Features of stools of breastfeeding babies

Answer 27

yellow watery stools are characteristic of breastfed babies, and overfeeding can lead to occasional explosive stools due to sugars in excess of GI absorptive capacity.

Question 28

MEC aspiration effects

Answer 28

• Alters the amniotic fluid reducing antibacterial activity and therefore increasing perinatal bacterial infection - Irritating to the fetal skin = increased erythema toxicum - Most severe complication of meconium passage in utero is aspiration of stained amniotic fluid before, during, and after birth Aspiration induces hypoxia via four major pulmonary effects: airway obstruction, surfactant dysfunction, chemical pneumonitis, and pulmonary hypertension.

Question 29

Insensible losses in premature babies

Answer 29

Very immature preterm infants (<1kg) may lose as much as 2-3 mL/kg/hr, partly because of immature skin, lack of subcutaneous tissue, and a large exposed surface area. Larger premature infants (2-2.5kg) nursed in an incubator may have an insensible water loss of approximately 0.6-0.7 mL/kg/hr.

Question 30

Premature infant with UTI causative organisms

Answer 30

Candida- most common pathogen (should be investigated for systemic infection) Klebsiella Coagulase negative staphylococcus **E.coli is the most common pathogen in term infants who present with a community acquired UTI but is much less likely to be seen in in preterm, ELBW infants. Extremely Low Birth Weight infants are babies born <1000g.

Question 31

Late haemorrhagic disease of the newborn causes

Answer 31

Lack of oral vitamin K (breast milk is low in vitamin K) Alterations in the gut flora due to long-term use of broad spectrum antibiotics Malabsorption of vitamin K Malabsorption of fat: in cystic fibrosis, biliary atresia results in vit K deficiency; reduced synthesis of Vit K dependent clotting factors sa FII,VII, IX,X, protein C and protein S. Advanced liver disease: Cirrhosis: synthesis of clotting factors damaged and vitamin K is ineffective.

Question 32

Physiologic jaundice mechanism

Answer 32

Increased bilirubin production because of increased breakdown of fetal erythrocytes. This is the result of the shortened lifespan of fetal erythrocytes and the higher erythrocyte mass in neonates. Hepatic excretory capacity is low both because of low concentrations of the binding protein ligandin in the hepatocytes and because of low activity of glucuronyl transferase, the enzyme responsible for binding bilirubin to glucuronic acid, thus making bilirubin water soluble (conjugation).

Question 33

What does antenatal corticosteroids reduce the risk of?

Answer 33

• RDS - Early onset sepsis - NEC - IVH - Neonatal death

Question 34

What does antenatal corticosteroids have NO effect on?

Answer 34

• CLD - Chorioamnionitis - Maternal death

Question 35

Answer 35

1. Optic disc
2. Central retinal vein
3. Central retinal artery
4. Retinal venules
5. Retinal arterioles
6. Macula
7. Fovea

Question 36

What is the pathogenesis of ROP

Answer 36

Question 37

What stage of ROP is demonstrated in the following images:

Answer 37

Stage 1

Stage 2

Stage 3

Question 38

What is the definition of a stillbirth + stillbirth rate?

Answer 38

• Stillbirth: Infant expelled from the birth canal at or after 20 weeks and/or weighing >400g which show NO life + no heart rate
• Stillbirth rate: number of stillbirths per 1000 live births + stillbirths

Question 39

When do you start screening for ROP + what is the reasoning behind this?

Answer 39

31 weeks OR 4 weeks postnatal age

• IGF in utero is suppled by the placental. When the baby is born IGF levels drop then slowly increase until it meats the “threshold” signal to start vascularization. This “threshold” is never met before 31 weeks, and therefore, there’s no point on checking eyes before 31 weeks corrected gestational age on any baby.

Question 40

What is the definition of perinatal mortality?

Answer 40

• Number of STILLBIRTHS + NEONATAL deaths / 100 stillbirths + livebirths

Question 41

What is considered NORMAL weight gain for:

Answer 41

• Term neonates may lose 10% in first few days. Typically regain birth weight by 10-14 days.
• Newborns gain ~30g/day (0-3 months)
• Infants 20g/day (3-6 months) 10g/day (6-12 months)
• Children 2yrs - puberty: 2kg/yr