Neonatology Flashcards
(318 cards)
1
Q
Which enzyme is most essential for bilirubin transformation from its unconjugated to conjugated form?
A
Uridine-diphosphoglucuronic glucuronosyltransferase (UDPGT)
2
Q
What is the most likely diagnosis in the context of cleft palate, dysmorphic face and a cardiac outflow tract defect?
A
DiGeorge syndrome
3
Q
Which gene locus is involved in DiGeorge syndrome?
A
Deletion of 22q11
4
Q
Which embryonic cell lineage is most likely to be involved in the defects associated with DiGeorge syndrome?
A
Neural crest cells
5
Q
What are the typical abnormalities associated with DiGeorge syndrome?
A
Pneumonic CATCH22
C - cleft palate
A - abnormal facies
T - thymic aplasia
C - cardiac outflow tract defects
H - hypocalcaemia (secondary to parathyroid aplasia)
22 - deletion of 22q11
6
Q
The failure of which structure to obliterate can lead to Meckel’s diverticulum in childhood?
A
Vitelline duct
7
Q
How can Meckel’s diverticulum present?
A
Intussusception
Bleeding - usually painless PR
Meckel’s diverticulitis
Intestinal obstruction
Incidental finding - asymptomatic
8
Q
What investigation can be used in Meckel’s diverticulum to identify ectopic gastric mucosa uptake?
A
Meckel scan using Technetium-99m
9
Q
What is the standard treatment for symptomatic Meckel’s diverticulum?
A
Surgical excision
10
Q
What are the potential clinical features of IUGR in the newborn?
A
Hypothermia and temperature instability
Polycythaemia
Hypoglycaemia
Neutropenia
Thrombocytopenia
Increased risk NEC
11
Q
What is the mechanism of action of phenobarbital?
A
Activation of the GABA-A receptor
12
Q
What is the first line anticonvulsant in both term and preterm neonates?
A
Phenobarbital
13
Q
What is the second line drug used in neonatal seizures?
A
Phenytoin
14
Q
At what gestational age does epidermal maturation complete?
A
34 weeks
15
Q
In general what are the differences in causes between symmetrical and asymmetrical IUGR?
A
Symmetrical tends to be caused by intrauterine infection
Asymmetrical tends to be caused by poor placental function
16
Q
What are the potential findings on upper GI contrast study where there is a malrotation with volvulus?
A
Failure of duodenojejunal junction to cross midline and lie left of the spine
‘Corkscrew’ sign if small bowel volvulus
Dilated proximal duodenum with failure of contrast to pass to 2nd part of duodenum
17
Q
What radiological test should be done in the neonate with bilious vomiting?
A
Upper GI contrast
18
Q
Which immunoglobulin are the antibodies to Rhesus antigens?
A
IgG
19
Q
Which immunoglobulin are the antibodies to A and B blood groups?
A
IgM
20
Q
Which clotting factors is vitamin K responsible for production of?
A
II, VII, IX and X
21
Q
What are the typical clotting results in vitamin K deficiency?
A
High INR and APTT
22
Q
What are the usual symptoms of vitamin K deficiency?
A
Bleeding:
- intracranial
- intraabdominal
- umbilical stump
- cephalohaematoma
- ecchymoses
- intrathoracic
- nose and gums
23
Q
What radiological test is done to confirm meconium ileus?
A
Contrast enema
24
Q
What findings are typically seen on contrast enema in meconium ileus?
A
Small-calibre colon
Dilated proximal bowel loops
Pellets of meconium in ileus
25
What are the characteristic facial features in FASD?
Thin vermilion border
Smooth philtrum
Short palpebral fissures
26
Which cell membrane channel is most responsible for lung fluid reabsorption after birth?
Sodium channels
27
What facilitates the switch from active chloride secretion to active sodium absorption within the lungs at birth?
Catecholamines and Glucocorticoids
28
What effects can cocaine use during pregnancy have on the child?
IUGR
Microcephaly
Subependymal haemorrhage and cyst formation
Behavioural issues
29
Why should a CrUSS be done in all babies born to mothers who used cocaine during pregnancy?
Increased risk of subependymal haemorrhage and cyst formation
30
What is the classical (albeit rare) triad of symptoms/signs in congenital toxoplasmosis?
Chorioretinitis
Intracranial calcifications
Hydrocephalus
31
Above what haematocrit percentage is considered polycythaemia within venous blood?
>65%
32
What is the treatment in cholestatic liver disease?
Ursodeoxycholic acid
Vitamins A, D, E and K
33
At what gestation does surfactant production begin?
24 weeks
34
What type of cell produces surfactant?
Type 2 pneumocytes
35
What type of organism is GBS (streptococcus agalactiae)?
Gram +ve anaerobic cocci
36
In the newborn is the activity of UGT (uridine diphosphate glucuronosyltransferase) less or more than in adults?
Less ~1% compared to adult activity
37
What immediate management should be done on the birth of an infant with CDH?
Intubation at birth
38
What structure has the most oxygenated blood in the fetal circulation?
Umbilical vein
39
What disorder typically presents as a cyanotic infant (particularly when feeding) that turns pink when crying?
Choanal atresia
40
What is the most common cause of hydrops fetalis?
Fetomaternal haemorrhage
41
At what gestational age does the major development of the eye occur?
Weeks 3-10
42
From what embryological layer does the majority of the globe of the eye form from?
Neural tube ectoderm
43
When should VZV IVIG only be given to a baby whose mother has varicella infection around pregnancy?
If the rash develops in the mother 7 days before to 7 days after delivery
44
When should VZV IVIG and Iv aciclovir be given to a baby whose mother has varicella infection around pregnancy?
If rash develops in the mother 4 days before - 2 days after delivery
Also any symptomatic infants
45
What is the classical triad of presenting symptoms in neonatal HSV infection?
Lesions of skin, mouth and eye
CNS involvement
Multi-organ dissemination
46
At what stage post-birth do the IgG levels in a baby drop to trough level?
3-4weeks
47
What is the most abundant lipid present in surfactant?
Phosphatidylcholine
48
What 2 factors create the minute volume?
Tidal volume and respiratory rate
49
Which factor of breathing is responsible for CO2 clearance?
Minute volume
50
What changes can be made to a ventilator to lower the PCO2 in a baby?
Increase tidal volume
Increase rate
Decrease PEEP
Reduce inspiratory time
Increase expiratory time
51
At what stage of embryological development does the distal airway epithelium thin out?
Canalicular stage (17-24weeks)
52
What is the only type of antigen which is able to cross the placenta?
IgG
53
What is the most likely primary cause of IVH in a preterm neonate?
Germinal matrix fragility due to prematurity
53
The presence of meconium passage in preterm labour strongly indicates which infection?
Listeria
54
What is the usual cause of neonatal alloimmune thrombocytopenia?
Paternal platelet antigen to which the mother has antibodies against which have crossed the placenta
55
What is the difference in maternal bloods between autoimmune neonatal thrombocytopenia and alloimmune neonatal thrombocytopenia?
Autoimmune - mother has antibodies to her own platelets so also has low platelets
Alloimmune - mother has antibodies to inherited paternal platelets so her platelets are normal
56
What is the most common defect in CDH?
Left sided Bochdalek hernia - posterolateral defect in the diaphragm
57
Which vessel follows on directly from the umbilical vein?
Ductus venosus
58
What are the typical signs/symptoms of the donor twin in TTTS?
Growth restriction
Reduced placental supply
Oligohydramnios
Pulmonary hypoplasia
59
What are the typical signs/symptoms of the recipient twin in TTTS?
Polyhydramnios
High output cardiac failure
Fetal hydrops
59
At what gestational age is the sucking reflex usually established?
34weeks
60
What is the usual treatment for umbilical granuloma?
Reassurance and review
61
Hirschsprung's disease is the congenital absence of which part of the intestinal wall?
Submucosal (Meissner's) plexus in the submucosal layer and the Myenteric (Auerbach's) plexus - between circular and longitudinal muscular layers
62
What is the subunit structure of HbF?
2-alpha and 2-gamma chains
63
Which is the main regulatory hormone for terminal maturation of the fetus and neonatal adaptation at birth?
Cortisol
64
What does cortisol release aid with in the neonate?
Lung maturation
Clearance of lung fluids
Increase of beta-receptor density
Catecholamine release
Maturation of the thyroid axis
65
Which immunoglobulin is present in breastmilk and is protective against NEC?
IgA
66
Which structure has the lowest oxygen saturations within the fetal circulation?
SVC
67
For preterm infants at what stage should PCO2 parameters be changed?
Day 4
68
What are the normal parameters for PCO2 for preterm infants on invasive ventilation 1-3days old?
4.5-8.5kPa
69
Of which diagnosis is the 'double-bubble' sign indicative of on AXR?
Duodenal atresia
69
What are the normal parameters for PCO2 for preterm infants on invasive ventilation >3days old?
4.5-10kPa
69
What is the underlying embryological issue in duodenal atresia?
Failure of recanalisation of the intestine
69
What are the A criteria for consideration of cooling in the neonate?
APGAR <5 at 10minutes
Need for resus >10mins life
pH <7 within 60min life
BE >16 within 60min life
70
What are the B criteria for consideration of cooling in the neonate?
Hypotonia
Altered state of consciousness
Abnormal primitive reflexes
71
When does a child's retinal blood vessel growth usually finish?
2-4weeks after birth
72
What blood results would be expected in autonomous insulin secretion? (glucose, insulin, c-peptide)
Hypoglycaemia
High insulin
High C-Peptide
73
What is the embryological origin of the intestinal plexi?
Ectoderm
74
Failure of what is the most likely cause of CDH?
Pleuroperitoneal canals to close
75
At what age do the fetal endocrine glands start to produce thyroid hormone, corticosteroids and insulin?
12 weeks
76
At what age does the fetus start to produce large volumes of dilute fetal urine?
10-11 weeks
77
What are the typical causes of asymmetrical IUGR?
Uteroplacental dysfunction
- maternal pre-eclampsia
- multiple pregnancy
- maternal smoking
- idiopathic
78
What are the major causes of symmetrical IUGR?
Prolonged period of poor growth starting in early pregnancy
- most commonly a small but normal baby
- fetal chromosomal disorder
- congenital infection
- maternal drug or alcohol abuse
- maternal chronic medical condition or malnutrition
79
What does reversed flow on doppler of the ductus venosus indicate?
Cardiac decompensation
79
What is a worrying sign in a MCA doppler in a fetus with IUGR and why?
Increased end-diastolic velocity
- evidence of cerebral dredistribution
79
Which organs/structures originate from the ectoderm?
CNS
PNS
Sensory epithelium (eye/ear)
Skin/Hair/nails
Pituitary, mammary and sweat glands
79
What does the ductus venosus doppler represent?
Physiological state of the right heart
79
What are the postnatal complications of an IUGR baby?
Hypothermia
Hypoglycaemia
Hypocalcaemia
Polycythaemia
79
In reduced, absent or reversed end diastolic flow in the umbilical artery doppler, what further measurements should be taken?
MCA and ductus venosus dopplers
79
What organs/structures originate from the mesoderm?
Skeleton
Dermis
Muscle
Urogenital system
GI/Cardiac muscle
Body wall
80
What organs/structures originate from the endoderm?
GI tract
Respiratory
Endocardium
80
By what fetal age is neural tube fusion completed?
End of week 4
80
What condition results from failure of the neural tube to close cranially?
Anencephaly
80
What condition results from failure of the neural tube to close caudally?
Spina bifida
81
What condition results from failure of skull ossification?
Meningoencephalocele
81
At what fetal age does neuronal proliferation begin and end?
Starts Day 42
Ends by 20 weeks
81
At what fetal age do primary sulci appear in an ordered manner?
8th-26th week
81
At what fetal age do secondary sulci develop?
Weeks 30-35
82
What is lissencephaly?
Disorder of neuronal migration, disputing the normal pattern of sulci and gyri
82
Which embryological layer does the neural plate develop and at what fetal age?
Ectoderm in the 3rd week
82
At the 4th week of fetal life what does the foregut develop?
Respiratory, hepatic and pancreatic buds
83
Failure of the respiratory bud to separate from the foregut leads to which condition?
Tracheoesophageal fistula
83
At what fetal age does the midgut herniate into the extraembryonic coelom?
6th week
84
By what age should the midgut rotate and return to the abdominal cavity?
10 weeks
84
What condition is caused by failure of the midgut to return to the abdominal cavity?
Exomphalos
85
What condition is caused by failure of rotation of the intestines before re-entering the abdominal cavity?
Malrotation +/- volvulus
85
What does the hindgut combine with to form the urogenital sinus?
Distal end of the surface ectoderm
86
At what fetal age does the urogenital sinus separate into urogenital system and rectum?
7 weeks
87
At what fetal age does the anal membrane rupture?
Week 9
88
What condition is caused by failure of separation of the urogenital sinus?
Rectal fistula
89
What condition is caused by failure of anal membrane rupture?
Rectal atresia or imperforate anus
90
What structures do the head and neck develop from?
Frontonasal prominence with six pharyngeal arches separated by five pharyngeal clefts
91
What structures form from the first pharyngeal arch?
Mandible
Upper lip
Palate
Nose
92
Cleft lip is due to the failure of fusion of which structures?
Maxillary and medial nasal processes
93
What structural abnormality occurs in cleft palate?
2 plates of the skull which form the hard palate do not completely join
94
Which teratogenic drug causes enamel hypoplasia and discolouring of the teeth?
Tetracycline
95
Which teratogenic drug causes birth defects of short or missing limbs?
Thalidomide
96
Which maternal medication causes vaginal or clear cell carcinoma in the baby?
Diethylstilbesterol
96
Which maternal anticonvulsants cause syndromes typically with craniofacial anomalies, cardiac defects, limb defects and developments delay?
Sodium valproate
Phenytoin
Carbamazepine
97
Which teratogenic drug most typically causes Ebstein anomaly?
Lithium
97
Which maternal drug can cause VACTERL?
Progesterone
98
What are the features of fetal warfarin syndrome?
Nasal hypoplasia
Microcephaly
Optic atrophy
Hydrocephalus
Congenital heart defects
Stippled epiphyses
Purpuric rash
98
Which maternal antimicrobial agent is associated with sensorineural deafness?
Streptomycin
99
What abnormalities can maternal isotretinoin cause to the fetus?
Craniofacial anomalies
Conotruncal cardiac defects
99
What effect can maternal methotrexate have on the fetus?
Microcephaly
Neural tube defects
Short limbs
100
What are the cardiac features of fetal alcohol syndrome?
VSD
100
How does alcohol affect the developing fetus?
Disrupts cellular differentiation and growth, inhibits cell migration and disrupts DNA synthesis
100
What are the neurological features of fetal alcohol syndrome?
Microcephaly
Anomalies of corpus callosum, cerebellar vermis, dentate gyrus
Cognitive impairment and DD
101
What are the craniofacial features of fetal alcohol syndrome?
Short palpebral fissures
Smooth philtrum
Maxilla hypoplasia
Cleft palate
Micrognathia
102
What are the limb features of fetal alcohol syndrome?
Joint abnormalities
103
What are the neurological features of opiate withdrawal in the neonate?
Irritability
High pitched cry
Hyperactivity
Reduced sleep
Tremors
Increased tone
Seizures (rare)
104
What are the GI features of opiate withdrawal in the neonate?
Poor feeding
Vomiting
Diarrhoea
105
What are the Autonomic features of opiate withdrawal in the neonate?
Sweating
Fever
Yawning
Sneezing
106
How is mild opiate withdrawal managed in the neonate?
Conservatively with swaddling, feeds and reduced sensory stimulation
107
How is moderate to severe opiate withdrawal managed in the neonate?
Oral morphine
108
What are the fetal issues in maternal diabetes mellitus?
Congenital malformations (cardiac and caudal regression syndrome)
Sudden IUD
Macrosomia
IUGR
Preterm labour
109
What are the neonatal issues in maternal diabetes mellitus?
Hypoglycaemia
Hyperbilirubinemia
RDS
Hypertrophic cardiomyopathy
Polycythaemia
110
In the UK which antibodies are the most common cause of haemolytic disease in a newborn?
Anti Kell and Anti-C
111
What are the features of neonatal thyrotoxicosis?
Tachycardia
Irritability
Poor feeding/weight gain
Diarrhoea
112
How should a baby with suspected maternal autoimmune thrombocytopenia be managed?
Unless severe nil treatment usually required
If required (petechiae, v. low platelet counts or bleeding) the IVIG and platelet transfusion
113
Which antibodies in a mother with SLE can cause congenital heart block in the fetus?
Anti-Ro and Anti-La
114
What causes transient neonatal myaesthenia?
Maternal AChR IgG antibodies transferred across the placenta
115
What are the symptoms of transient neonatal myaesthenia?
Transient hypotonia
Feeding difficulties
Respiration difficulties
116
How is transient neonatal myaesthenia diagnosed?
Administration of anticholinesterase leads to rapid recovery and is diagnostic
117
What causes perinatal alloimmune thrombocytopenia?
Maternal antibodies which cross the placenta and bind to fetal platelets
118
How is perinatal alloimmune thrombocytopenia managed?
IVIG and platelet transfusion if severe
119
What are the ophthalmic features of Rubella?
Glaucoma
Cataracts
Chorioretinitis
Microphthalmia
120
What are the ophthalmic features of CMV?
Chorioretinitis
121
What are the ophthalmic features of Toxoplasma?
Chorioretinitis
Microphthalmia
Cataracts
122
What are the CNS features of rubella?
Microcephaly
123
What are the CNS features of CMV?
Periventricular calcification
Microcephaly
124
What are the CNS features of toxoplasma?
LDs
Microcephaly
Peripheral calcification
Hydrocephalus
Hypotonia
Seizures
125
What are the cardiac features of rubella?
PDA
PAS
126
What are the hearing features of rubella?
SN deafness
126
What are the bony features of rubella?
Viral osteodystrophy
127
What are the hearing features of CMV?
SN deafness
128
What are the bony features of CMV?
Viral osteodystrophy
129
What are the bony features of toxoplasma?
Epiphyseal plate anomaly
130
What is the treatment of choice for CMV?
Oral valganciclovir
130
How long should antibiotics be given before delivery to prevent congenital syphilis?
4 weeks
130
What specific features are associated with congenital syphilis?
Rash and desquamation of soles of feet and palms of hands
Metaphyseal bone lesions
130
What condition can parvovirus B19 rarely cause in the fetus?
Severe fetal anaemia and hydrops
131
What part of the fetal circulation has the lowest vascular resistance?
Placenta
132
What part of the fetal circulation has the highest vascular resistance?
Umbilical arteries
132
What part of the fetal circulation has the highest oxygenation?
Umbilical vein
133
Which of the fetal ventricles is most dominant?
Right ventricle - 66% of combined ventricular output
134
What is the usual fetal PaO2?
2-4kPa
134
Does HbF have a lower or higher affinity for 2,3 diphosphoglycerate?
Lower
134
What is the role of 2,3 diphosphoglycerate?
Binds to deoxyhemoglobin and facilitate oxygen transport
134
In which direction is the oxygen saturation curve shifted in the fetus compared to an adult?
Left
135
What does the ductus venosus become after it ceases to function following delivery?
Ligamentum venosum
136
Which medication is used to maintain ductus arteriosus patency?
Prostaglandin E
137
When does functional closure of the foramen ovale occur typically?
In the first few breaths after birth
137
When does anatomical closure of the foramen ovale occur typically?
By 3 months of age
137
When does functional closure of the ductus arteriosus occur typically?
50% by 24hours
75% by 48hours
~100% by 96hours
137
Which conditions may lead to PPHN?
Perinatal asphyxia
Neonatal hypothermia
Sepsis
Meconium aspiration
137
When does anatomical closure of the ductus arteriosus occur typically?
By 3 months of age
137
What is the purpose of antenatal steroids?
Reduces rate of:
- RDS
- IVH
- Neonatal death
137
Why is magnesium sulphate given antenatally for mothers of preterm infants?
Reduces risk of CP in <32week gestation infants
138
What is the cause of RDS?
Surfactant deficiency
138
What does surfactant deficiency in RDS cause within the lungs?
High surface tension on alveolar surface
Difficulty in achieving adequate FRC
Interferes with gas exchange
139
What is Laplace's Law?
P = 2T/r
P- pressure
T - surface tension
r - radius
140
How does Laplace's Law apply for the preterm infant and their alveoli?
In the absence of surfactant the surface alveoli pressure is greater and so small alveoli collapse and larger ones expand
140
What is pulmonary surfactant made up of?
Phospholipids (85%)
Proteins (10%)
141
What type of cells produce pulmonary surfactant?
Type II epithelial cells
141
How does DPPC aid in alveolar expansion?
Forms a stable monolayer which generates a lower surface tension
141
What are the most common type component of phospholipid within pulmonary surfactant?
Phosphatidylcholine (PC) - particularly DPPC
141
How do the surfactant specific proteins SP-B and SP-C contribute to surfactant and alveolar opening?
Promote rapid absorption of phospholipids therefore creating sustained low surface tension after dynamic compression
142
How does SP-C deficiency present?
Usually later as chronic interstitial lung disease
142
How is SP-B deficiency inherited?
AR
142
What do animal-derived surfactants typically contain?
Phospholipids
SP-B
SP-C
142
Does surfactant administration reduce rates of BPD?
No
142
What is the main component of synthetic surfactant?
DPPC
142
What is the main role of SP-A and SP-D?
Form the defence barrier against pathogenic organisms
Recycling of surfactant
142
What does SP-B deficiency cause?
It is lethal, causing fulminant respiratory failure
142
What is DPPC?
Dipalmitoyl phosphatidylcholine
142
What does left-to-right shunting of blood in a PDA cause within the heart?
Increased pulmonary blood flow
Higher venous return to the left heart
142
What is the first response usually seen following surfactant administration
Improvement in oxygenation
Usually within 10 minutes
142
What is the second stage of improvement following surfactant delivery?
Recycling of components of surfactant leading to sustained improvements in oxygenation
142
What is the pharmacological treatment used in PDA?
Indomethacin or ibuprofen
142
What longer term effects may arise in the heart with PDA?
Pulmonary oedema
CCF
Pulmonary haemorrhage
Increased risk of BPD
142
If a PDA is haemodynamically significant what additional complications may arise from this?
Hypotension (esp. diastolic)
Reduced gut and renal perfusion
Increased risk of NEC
Increased risk of IVH
142
What clinical signs can be seen in a baby with PDA?
Tachypnoea
Increased FiO2
Increased ventilatory support/struggling to wean
Apnoea
Hepatomegaly
Impaired weight gain
Murmur - pansystolic or systolic
142
What is the mechanism of action of medical management for PDA?
Decreased production of PGE2 (which is keeping duct open)
142
Out of the medical management options for PDA, which is first line?
Ibuprofen
143
What is the clinical presentation of NEC?
Abdominal distension and tenderness
Bilious aspirates
Bloody stools
Intramural air on x-ray
143
Do term babies typically have higher or lower levels of IgG than their mothers?
Higher
143
What immunoglobulins is breast milk rich in?
IgA
144
What are the histological features of NEC?
Necrosis of mucosa
Microthrombus formation
Patchy mucosal ulceration
Oedema
Haemorrhage
145
What is the greatest risk factor for IVH?
Prematurity
145
What is the most common part of the bowel involved in NEC?
Terminal ileum or sigmoid colon
145
How can feeding increase the risk of NEC?
Rapid increase in enteral feeds
Formula milk
Hypertonic formula
145
What are the prenatal risk factors for developing IVH?
Prematurity
IUGR
HIE
Chorioamnionitis
T-T transfusion
145
What is the main risk factor for NEC?
Prematurity
145
What is the surgical management for NEC?
Resection of non-viable bowel +/- ileostomy/colostomy
145
What are the perinatal risk factors for NEC?
IUGR
Perinatal asphyxia
146
What are the postnatal risk factors for NEC?
PDA
Asphyxia
146
What is the medical management for NEC?
Stop feeds
Place a large-bore NGT/OGT for intestinal decompression
Broad spectrum antibiotics
146
What are the findings in grade II IVH?
IVH <50% of ventricular area on parasagittal view
146
What are the findings in grade I IVH?
Isolated GMH
146
What is the greatest risk factor seen on CrUSS for developing CP?
Occipital cystic PVL
146
What are the postnatal risk factors for developing IVH?
RDS
CVS instability
Pneumothorax
Rapid volume expansion
146
What are the findings in grade III IVH?
IVH >50% of ventricular area on parasagittal view - usually distends the lateral ventricle
146
What are the findings in grade IV IVH?
Haemorrhagic parenchymal infarct - may develop into porencephalic cyst
147
What is thought to be the pathogenesis for IVH?
Immature germinal matrix capillary network
Systemic BP fluctuations with impaired cerebral autoregulation
Coagulopathy
147
What is thought to be the pathogenesis for PVL?
Hypoperfusion of periventricular white matter and inflammatory cytokine response
- oligodendroglial injury
- myelin loss
147
What are the postnatal risk factors for developing PVL?
Hypocarbia and alkalosis
CVS instability
NEC
Postnatal corticosteroids
147
What is seen within the brain tissue within cystic PVL?
Focal macroscopic areas of necrosis in periventricular white matter leading to small cysts
147
What percentage of babies with Grade IV IVH will develop CP by 2 years of age?
50%
147
What percentage of babies with Grade III IVH will develop CP by 2 years of age?
25%
147
What percentage of babies with Grade I and II IVH will develop CP by 2 years of age?
9%
147
What can cystic PVL present with in the child?
Diplegic CP
Poor visual spatial skills
Low IQ
147
What causes the poor bone mineralisation in preterm infants?
Phosphate deficiency
147
What are the typical bloods seen in osteopenia of prematurity?
Low phosphate
High/normal calcium
High ALP
148
What are the underlying lung mechanics of BPD in preterm infants?
Reduction in lung compliance and increased airway resistance leading to increased work of breathing
148
What are the signs seen in poor bone mineralisation in preterm infants?
Widening and cupping or wrists, knees and ribs on x-ray
Failure in linear growth
Increased rate of fractures
148
What is the treatment of osteopenia of prematurity?
Oral phosphate
Oral vitamin D supplements
148
What is thought to be the cause of TTN in babies?
Lower concentration of circulating catecholamines (especially following CS)
Absence of thoracic squeezing to clear fluid following CS
148
What are the longer term risks for infants with BPD?
Higher risk of death in first year of life
Reactive airway disease
Increased susceptibility to viral infection (esp. RSV)
Growth failure
Neurodevelopmental abnormalities
149
What is the most important factor for clearance of lung fluid in the neonate other than breathing?
Reabsorption of alveolar fluid through sodium channels in the lung epithelium - influences by catecholamines
150
What is the likely pathophysiology in meconium aspiration syndrome?
Proximal and distal airway obstruction
Pulmonary parenchymal injury which can lead to surfactant inactivation
PPHN due to hypoxaemia in utero
151
How is PPHN in meconium aspiration syndrome managed?
Nitric oxide
ECMO
152
What does PPHN cause with regards to the blood flow through the heart?
Right to left shunting through FO and DA
153
What factors can lead to vasoconstriction and elevated pulmonary artery pressure, therefore leading to failure of adaptation from fetal to neonatal circulation?
Hypoxia
Hypercarbia
Acidosis
154
What are some conditions which lead to increased PVR where pulmonary vascular morphology is normal?
Asphyxia
Meconium aspiration
Severe parenchymal lung disease
Sepsis/pneumonia
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What are some conditions which lead to increased PVR where pulmonary vascular morphology is abnormal?
Pulmonary hypoplasia
CDH
CPAM
LVO tract obstruction
APVD
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What treatment can be given antenatally for CDH in severe cases - although is mainly used in clinical trials?
FETO
- fetal endoscopic tracheal occlusion
157
At what stage is FETO performed and reversed?
Performed at 26-28 weeks and reversed at 34weeks
158
How should an infant with known CDH be managed at birth?
Intubation and continuous ventilation initiated as soon as possible
Bag and mask ventilation avoided
Continuous drainage of gas from the abdomen
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What is the treatment for CDH?
Surgical repair of the diaphragm and reduction of the bowel into the abdominal cavity
160
What is the most common type of tracheo-oesophageal fistula?
Oesophageal atresia with distal tracheo-oesophageal fistula (91% cases)
161
How common are cases of TOF with both proximal and distal fistulas?
1% TOF cases
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How common is H-type TOF?
4% cases of TOF
161
How common is oesophageal atresia with proximal TOF and distal oesophagus as a blind pouch?
4% TOF cases
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What is tracheomalacia?
Reduction in the cartilage to soft tissue ratio in the cartilaginous rings of the trachea resulting in collapse on expiration
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What is bronchopulmonary sequestration?
A mass of non-functioning lung tissues not connected to the tracheo- bronchial tree
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What is congenital pulmonary lymphangiectasis (CPL)?
Marked distension of pulmonary lymphatics which presents as pleural effusion (chylous)
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Where do the masses on non-functioning lung tissue in bronchopulmonary sequestration get their blood supply from?
One or more anomalous arteries arising from the aorta
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How does bronchopulmonary sequestration appear on a CXR?
Triangular or oval-shaped lung tissue on one side of the chest, usually the left
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How do cysts appear in microcystic CPAM?
Cysts <5mm and appear as a solid mass
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How do cysts appear in macrocystic CPAM?
Cysts >5mm in diameter and visible of fetal USS
164
What are the 2 types of CPAM?
Macrocystic and Microcystic
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What are congenital pulmonary airway malformations (CPAM)?
Pulmonary maldevelopment with cystic replacement of smaller airways and distal lung parenchyma
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What conditions may lead to pulmonary hypoplasia?
Renal agenesis
Oligohydramnios
CDH
Large pleural effusions
Congenital anomalies of the neuromuscular system
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Does macrocystic or microcystic CPAM have a better prognosis?
Macrocystic
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If CPL is noted antenatally what can be done?
Catheter shunt between chest and amniotic cavity inserted
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What oxygen tension in neonates is needed to maintain arterial saturation >90%?
5.3-8kPa
166
What conditions in the neonate cause hypoxaemia through extrapulmonary shunts?
PHTN
Cyanotic CHD
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What syndromes is CPL associated with?
Noonan's syndrome
Down's syndrome
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What fetal complications can co-exist with CPAM?
Mediastinal shift
Polyhydramnios
Pulmonary hypoplasia
Hydrops fetalis
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What conditions in the neonate cause hypoxaemia through V/Q mismatch?
RDS
Pneumonia
MAS
BPD
167
What must happen when oxygen transport is reduced below metabolic demand in the neonate?
Metabolism must be maintained anaerobically or the tissue metabolic rate must be reduced
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Does fetal or adult Hb have higher oxygen affinity?
Fetal
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Does fetal or adult Hb have higher p50?
Adult
170
By what age does p50 reach adult levels in the neonate?
4-6months
171
How is the oxygenation index calculated?
OI = MAP x FiO2 x 100/PaO2
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How is lung compliance calculated?
Volume / Pressure
172
How is resistance calculated with regards to ventilation?
Pressure / Flow
172
What is the usual lung compliance in infants with normal lungs?
3 - 5ml/cmH2O/kg
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What is the usual lung compliance in infants with RDS?
0.1 - 1ml/cmH2O/kg
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What is a normal lung resistance in infants with normal lungs?
25 - 50 cmH2O/L/second
174
How is resistance affected in infants with small ETTs in situ?
Increased up to 100cmH2O/L/second
175
What is resistance in the context of neonatal lung ventilation?
The ability of the gas-conducting parts of the respiratory system to resist air flow
176
What is compliance in the context of neonatal lung ventilation?
The elasticity or distensibility of the respiratory system
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What is the time constant in the context of neonatal ventilation?
The time (msec) necessary for the alveolar pressure (or volume) to reach 63% of a change in airway pressure (or volume)
176
How is time constant calculated?
Compliance x resistance
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What duration in time constants is required for complete inspiration or expiration in the neonate?
3 - 5 time constants
178
What features cause the time constant to be increased?
High compliance
High resistance
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Will the time constant typically be increased or decreased in RDS?
Decreased
179
What features cause the time constant to be decreased?
High resistance
Low compliance
179
Which medications can increase risk of bilirubin neurotoxicty?
Ceftriaxone
Salicylates
Ibuprofen
Aminophylline
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Which areas of the brain are typically involved in neurological bilirubin toxicity?
Basal ganglia - esp. globus pallidus and subthalamic nuclei
Nuclei of oculomotor, vestibulocochlear and facial nerves
Cerebellar nuclei
Anterior horn cells of the spinal cord
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Will the time constant typically be increased or decreased in BPD?
Increased
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What does a pressure controller ventilator do?
Controls airway pressure making it rise above body surface pressure (PPV) or making it fall below body surface pressure (NPV)
180
What does a flow controller ventilator do?
Controls TV directly but does not measure it directly. Gas delivery is limited by flow.
180
What does a volume controller ventilator do?
Controls and measures tidal volume despite change in loads
180
What does bilirubin bind with before being taken up in the liver?
Albumin
181
What does a time controller ventilator do?
Controls the timing of the ventilatory cycle but not pressure or volume
181
What is a normal base deficit in a healthy term infant?
3 - 5 mEq/L
181
What are the final stages of acute bilirubin encephalopathy if left untreated?
Coma
Fever
Apnoea
Seizures
Death
181
Which factors in the neonate increase risk of bilirubin neurotoxicity?
High levels of free bilirubin
Disruption of BBB integrity
Hypercapnia, hyperosmolality, acidosis
181
What happens to bilirubin which exceeds the albumin-binding capacity?
Released into the circulation
181
What happens to bilirubin once transported into the liver?
Dissociated from albumin
Transported into hepatocytes
181
What are the initial signs of acute bilirubin encephalopathy?
Lethargy
Hypotonia
Poor suck
181
What is the intermediate phase of acute bilirubin encephalopathy?
Stupor
Irritability
Hypertonia
High pitched cry
182
Which volatile gas is a useful marker of bilirubin production?
Carbon monoxide
182
What enzyme breaks down biliverdin into bilirubin?
Biliverdin reductase
182
What 4 things are RBCs broken down into within the reticuloendothelial system?
Iron
Globulin
Carbon monoxide
Biliverdin (precursor to bilirubin)
182
What is bilirubin produced by?
The breakdown of haem present in haemoglobin, myoglobin and cytochromes
182
What is the neonatal production rate of bilirubin?
100-120 micromol/kg/day
182
How is bilirubin conjugated?
Bound to cytosolic proteins (glutathione S-transferases or ligandins) within hepatocytes and UGT acts upon it to form mainly bilirubin diglucuronide and some bilirubin monoglucuronide
182
What types of bilirubin crosses the BBB?
Unconjugated
182
What happens to most conjugated bilirubin excreted in the bile?
Hydrolysed back into unconjugated bilirubin and transported back into the liver
182
How does bilirubin give faeces it's brown colour?
Converted to stercobilinogen and then oxidised to stercobilin
182
How does bilirubin give urine it's colour?
Urobilinogen is oxidised to urobilin which gives urine it's colour
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