Neonatal medicine Flashcards
What drug can be given to reverse neonatal respiratory depression caused by maternal opiate analgesia?
Naloxone
How do you decrease the risk of hypothermia is preterm neonates?
Infants, with the exception of the face, should be placed into a plastic bag or wrapped in plastic sheeting.
What is asymmetrical FGR and what does it mean?
The weight or abdominal circumference lies on a lower centile than that of the head. Usually caused by placental dysfunction, these infants rapidly put on weight after birth
What is symmetrical FGR?
The head circumference is equally reduced compared to the abdomen. It is usually a normal, small baby but may be due to a fetal chromosomal disorder or syndrome, they are likely to stay small after birth
What is a IUGR fetus at risk of?
Intrauterine hypoxia and ‘unexplained’ intrauterine death
Asphyxia during labour and delivery
Hypothermia due to their relatively large surface area
Hypoglycaemia from poor fat and glycogen stores
Hypocalcaemia
Polycythaemia
What are the problems associated with large for gestational age babies?
Birth asphyxia from a difficult delivery
Birth trauma, especially should dystocia
Hypoglycaemia due to hyperinsulinism
Polycythaemia
What do you look at on the routine examination of a newborn infant?
Birthweight (weight and centile) and gestational age General observation: appearance, posture and movements Head circumference Fontanelle The face If plethoric or pale Jaundice The eyes The palate Breathing and chest wall movement Auscultate the heart Palpate the abdomen, femoral pulses Genitalia and anus Muscle tone The whole of the back and spine The hips
Why do you look at the fontanelle in a newborn examination?
A tense fontanelle when the baby is not crying may be due to raised intracranial pressure (cranial US needed). A tense fontanelle is also a late sign for meningitis
Why do you take the femoral pulses in a newborn examination?
The pulse pressure reduced in coarctation of the aorta. This can be confirmed be measuring the BP in the arms and legs. The pulse pressure is increased if there is a patent ductus arteriosus
What are some lesions in newborns that resolve spontaneously?
Peripheral cyanosis of the hands and feet
Traumatic cyanosis
Swollen eyelids and distortion of the head
Subconjunctival haemorrhage
Cysts of the gum
Breast enlargement
White vaginal discharge or small withdrawal bleed
Umbilical hernia
What are some significant abnormalities detected on the newborn screening examination?
Port-wine stain
Strawberry naevus
Natal teeth consisting of the front lower incisors (should be removed)
Extra digits
Heart murmur
Midline abnormality over the spine or skull
Palpable or large bladder
What are the risk factors of DDH?
Female sex (six fold)
Positive family history (20% of affected)
Breech presentation (30% of affected)
Neuromuscular disorder
What can Vitamin K deficiency result in?
Haemorrhagic disease of the newborn. In most, the haemorrhage is mild, such as bruising, haematemesis and melaena, or prolonged bleeding of the umbilical stump or after a circumcision. However, it can cause intracranial haemorrhage, half of whom are permanently disabled or die.
When does vitamin K deficiency present?
During the first week of life or late, from 1 to 8 weeks of age
Is breast milk or formula milk better for vitamin K deficiency.
Formula milk, breast milk is a poor source of vitamin K.
Are there any medications that the mother is taking whilst breast feeding that may worsen vitamin K deficiency?
Anti-convulsants, they impair the synthesis of vitamin K
How is vitamin K deficiency prevented?
All newborn infants are given an IM injection of vitamin K.
What is the routine biochemical screening of the newborn called?
Guthrie test
What is screened for in the Guthrie test?
Phenylketonuria Hypothyroidism Haemoglobinopathies (sickle cell, thalassaemia) Cystic fibrosis MCAD deficiency (mitochondrial disease)
What is neonatal hypoxic-ischaemic encephalopathy?
In perinatal asphyxia, gas exchange, either placental or pulmonary, is compromised, resulting in respiratory depression. Hypoxia, hypercarbia and metabolic acidosis follow. Compromised cardiac output diminishes tissue perfusion, causing hypoxic-ischaemic injury to the brain and other organs
What are some significant hypoxic events immediately before or during labour or delivery that can cause hypoxic-ischaemia encephalopathy?
Before labour: maternal hypo- or hypertension, fetal anaemia or IUGR
During labour: excessive or prolonged uterine contractions, placental abruption, ruptured uterus, cord compression (prolapse or shoulder dystocia)
After delivery: failure to breathe
What are the clinical manifestations of hypoxic-ischaemic encephalopathy?
Mild - irritable, responds excessively to stimulus, hyperventilation, impaired feeding
Moderate - marked abnormalities of tone and movement, cannot feed, seizures
Severe - no normal movements or response to pain, fluctuating tone (hypo/hyper), prolonged seizures, multi-organ failure
How would you manage hypoxic-ischaemic encephalopathy?
Respiratory support aEEG (a - amplitude integrated) Treatment of seizures Fluid restriction (transient renal impairment) Treat hypotension Monitor and treat electrolyte imbalances
What is the prognosis of hypoxic-ischaemic encephalopathy?
Mild - expect complete recovery
Moderate - may be better by 2 weeks but if not full recovery is unlikely
Severe - mortality is 30-40%, over 80% of survivors have neurodevelopment disabilities
What are some soft tissue injuries that can occur during delivery?
Oedema and bruising (caput succedaneum [extending beyond the margins of the skull bones], chignon [from ventouse delivery])
Haematoma (cephalhaematoma [below the periosteum, confined within the margins of the skull sutures])
Abrasions
Forceps marks on face
What causes brachial nerve palsy and in what conditions is it more common?
It results from traction to the brachial plexus nerve roots. It may occur at breech deliveries or with shoulder dystocia
What would an upper nerve root (C5/6) injury result in?
Erb palsy
Do nerve palsies recover?
Most resolve completely by 2 years but they should be referred to an orthopaedic or plastic surgeon if not resolved by 2-3 months
What fractures can occur during delivery?
Clavicle (shoulder dystocia, good prognosis, no specific treatment)
Humerus/femur (usually mid-shaft, occurring at breech deliveries, or fracture of the humerus at shoulder dystocia, heal rapidly with immobilisation)
What are some medical problems of preterm infants?
Resuscitation at birth Respiratory (respiratory distress, pneumothorax, apnoea and bradycardia) Hypotension Patent ductus arteriosus Temperature control Metabolic (hypo- glycaomia and calcaemia, electrolyte imbalance) Nutrition Infection Jaundice
What is the pathophysiology of respiratory distress syndrome?
Deficiency of surfactant, which lowers surface tension, leading to widespread alveolar collapse and inadequate gas exchange.
Is respiratory distress syndrome more severe in boys or girls?
Boys
In which neonates is respiratory distress syndrome more common?
It is common in infants born before 28 weeks gestation. It is rare at term but may occur in mothers with DM.
What are the clinical features of RDS?
At delivery or within 4 hours of birth: Tachypnoea > 60 breaths/min Laboured breathing with chest wall recession (sternal and subcostal indrawing) and nasal flaring Expiratory grunting Cyanosis
Why does expiratory grunting take place in RDS?
In order to try to create positive airway pressure during expiration and maintain functional residual capacity
What does a characteristic X-ray of RDS show?
Diffuse granular or ‘ground glass’ appearance of the lungs and an air bronchogram, where the larger airways are outlined. The heart border becomes indistinct or obscured completely with severe disease
How do you treat RDS?
Raised ambient oxygen, supplemented with continuous positive airway pressure (delivered via nasal cannulae) or artificial ventilation via a tracheal tube
How is RDS prevented?
Steroids in high risk pregnancies
How does RDS lead to pulmonary interstitial emphysema?
Air from the over distended alveoli may track into the interstitial, resulting in PIE
How does PIE lead to pneumothorax?
Air leaks into the pleural cavity and causes a pneumothorax
How is a neonatal pneumothorax detected?
Breath sounds and chest movement on the affected side are decreased but it is difficult to detect clinically. Transillumination with a bright fiberoptic light source applied to the chest wall may show a pneumothorax
How do you prevent a pneumothorax?
Infants are ventilated with the lowest pressures that provide adequate chest movement and satisfactory blood gases.
When are episodes of apnoea, bradycardia and desaturation common?
In very low birthweight infants until they reach about 32 weeks gestational age.
Acutely, when does bradycardia occur?
It may occur when an infant stops breathing for over 20-30 secs or when breathing continues against a closed glottis.
What may be the causes of neonatal bradycardia?
In many cases immaturity of central respiratory control. Must rule out hypoxia, infection, anaemia, electrolyte disturbances, hypoglycaemia, seizures, heart failure or aspiration due to reflux
How would you treat neonatal bradycardia?
Breathing will often start again after gentle physical stimulation. Caffeine often helps. Continuous positive airway pressure (CPAP) may be needed if episodes are frequent
What are the consequences of hypothermia in a neonate?
Increased energy consumption, resulting in hypoxia and hypoglycaemia, failure to gain weight and increased mortality.
Why are neonates particularly susceptible to hypothermia?
Large SA:volume ratio
Thin skin that is very heat permeable
Little subcutaneous fat for insulation
How can you prevent the heat loss in newborn infants?
Convection: raise temperature of ambient air in incubator, clothe (including head), avoid draughts.
Radiation: cover baby, double wall for incubators
Evaporation: dry and wrap at birth, humidify incubator
Conduction: nurse on heated mattress
In which neonates in patent ductus arteriosus most common?
In infants with RDS
What are the clinical features on a PDA?
May be asymptomatic but may cause apnoea and bradycardia, increased oxygen requirement and difficulty in weaning the infant from artificial ventilation. With increasing circulatory overload, signs of heart failure may develop
What would you find on examination of PDA?
‘Bounding’ pulses from an increased pulse pressure, the precordial impulse becomes prominent and a systolic murmur may be audible
How would you treat PDA?
If symptomatic, prostaglandin synthesise inhibitor, indomethacin or ibuprofen is used. If this fail, surgical libation will be required
How do you feed ‘healthy’ neonates?
Infants of 35/36 weeks are mature enough to suck and swallow milk. Less mature infants will need to be fed via an oro- or nasogastric tube.
How would feed very immature or sick neonates?
Parenteral nutrition through a central venous catheter, inserted peripherally (PICC lines, peripherally inserted central catheters).
What are the risk factors of PICC lines?
Significant risk of septicaemia (use aseptic technique). Other risks include thrombosis of a major vein
What condition does cow’s milk formula increase the risk of in neonates?
NEC
Why are preterm infants at increased risk of infection?
IgG is mostly transferred across the placenta in the last trimester and no IgA or IgM is transferred.
Are brain haemorrhages common in neonates and how are the screened for?
They occur in 25% of very low birthweight infants and are easily recognised on cranial US scans. Most occur in the first 72hours of life.
What are some risk factors for neonatal brain haemorrhage?
Perinatal asphyxia, severe RDS, pneumothorax
What is necrotising enterocolitis?
Bacterial invasion of ischaemia bowel wall