Neonates Flashcards
Revise neonates
Effects of warfarin on the foetus during pregnancy
- Hypoplastic nasal bridge - Chondrodysplasia - CNS malformations - Increased risk of bleeding
Effects of sodium valproate on the foetus during pregnancy
Neural tube defects
Types of open neural tube defects (spina bifida aperta)
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
Types of closed neural tube defects (spina bifida occulta)
- Lipomyelomeingocele - Lipomeningocele
Klumpke palsy
- 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.
Erb’s palsy
- 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).
Congenital zika features
- 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
Benign familial neonatal epilepsy
- 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.
SCN1A mutation
- 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.
DEPDC5 mutation
- DEPDC5 is a gene which is responsible for modulating the mTOR pathway. - Results in a familial focal epilepsy, often associated with focal cortical dysplasia.
MECP2 mutation
- 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.
Clinical features of congenital CMV
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
Clinical features of hypermagnesaemia in neonates
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.
Alagille Syndrome
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.
Rhesus negative mother, risk of Rh sensitisation after delivery of 1st child
16% if Rh+ fetus and mother are ABO compatible 2% if Rh+ fetus and mother are ABO incompatible 2-5% after an abortion
Isoimmune haemolytic disease: is rhesus of ABO disease more common?
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.
Is beta thalassaemia associated with fetal hydrops?
NOT associated with fetal hydrops as fetal haemoglobin (α2γ2) compensates
Five phases of lung development
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)
Bronchogenic cysts
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).
Congenital lobar emphysema
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.
Congenital pulmonary airway malformation (CPAM)
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.
In the fetus with a structurally normal heart. The percentage of pulmonary arterial blood flow that is directed through the ductus arteriosus is
90%
Phenylketonuria
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.
HIV + pregnant women: risk of transmission+ ways to reduce transmission
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.
