Neonatal and Newborn Flashcards
What % of babies are visibly jaundiced in the first week of life?
50%
What is jaundice?
Jaundice = state of hyperbilirubinaemia
Serum bilirubin exceeds 85μmol/L
Describe the stages of bilirubin metabolism
1) Haemoglobin (from RBCs) is broken down into haem and iron in the spleen
2) Bilirubin is the main breakdown product of haem
3) Unconjugated bilirubin = lipid soluble. It is transported round the blood bound to albumin
4) In the liver, it is actively transported into hepatocytes where it is conjugated with glucoronic acid by the enzyme UDPGT
5) Conjucated bilirubin = water soluble. It is stored in the gallbladder and excreted as a component of bile
6) Bile is broken down by gut bacteria into stercobilinogen and urobilinogen
7) A small amount of urobilinogen is reabsorbed and then excreted by the kidneys
What are the 3 types of jaundice?
1) Pre-hepatic
2) Hepatocellular / intrahepatic
3) Post-hepatic
Outline what pre-hapatic jaundice is
What levels would be raised?
Excessive RBC breakdown overwhelms the livers ability to conjugate bilirubin
= Unconjugated hyperbilirubinaemia
Any bilirubin that managed to become conjugated will be excreted normally, it is unconjugated bilirubin that remains in the blood stream to cause jaundice
Outline what hepatocellular / intrahepatic jaundice is
What levels would be raised?
Results from dysfunction of the liver itself. Damaged hepatocytes lose the ability to metabolise and excrete bilirubin
= Unconjugated hyperbilirubinaemia
The small bile ducts may also become damaged or obstructed, meaning conjugated bilirubin leaks into the blood
= Conjugated hyperbilirubinaemia
Thus hepatic jaundice = MIXED PICTURE
Outline what post-hepatic jaundice is
What levels would be raised?
Obstruction of biliary drainage
= Conjugated hyperbilirubinaemia
What is physiological jaundice in a neonate?
= Slow change to conjugation
In foetus, bilirubin stays unconjugated to allow placental excretion
After birth, conjugation and hepatic excretion takes over
If this happens slowly = physiological (hepatocellular) jaundice
THIS IS NOT PATHOLOGICAL
Is jaundice within the first 24 hours of life concerning?
YES
JAUNDICE WITHIN THE FIRST 24HRS OF LIFE IS ALWAYS PATHOLOGICAL
What are some causes of neonatal jaundice <24hrs? (Unconjugated and conjugated)
Unconjugated:
- Haemolytic disease
- Neonatal Sepsis
Conjugated:
- Neonatal hepatitis
- Congenital infections (rubella, CMV, syphilis)
What are some causes of neonatal jaundice 24hrs - 2 weeks? (Unconjugated and conjugated)
Unconjugated:
- Physiological (exacerbated by bruising, polycythaemia, dehydration)
- Hypothyroidism
- Haemolysis / sepsis
Conjugated:
- Neonatal hepatitis
- Congenital infections (rubella, CMV, syphilis)
What are some causes of neonatal jaundice >2 weeks? (Unconjugated and conjugated)
Unconjugated:
- Breast milk jaundice
- Haemolysis / sepsis
- Hypothyroidism
Conjugated: - Biliary atresia - Choledochal cyst - Neonatal hepatitis (alpha-1 antitrypsin, TORCH, galactosaemia, CF)
What is breast feeding jaundice and what is breast milk jaundice?
Breast feeding jaundice = failure to establish breast feeding and so child dehydrated (thus less bilirubin excreted in urine so builds up)
Breast milk jaundice = substance passes through breast milk into baby which increases activity of glucouronidase, leading to build up of bilirubin NB not a reason to stop breast feeding
Jaundice within first 24 hrs is usually due to haemolysis. List 3 causes of haemolysis leading to neonatal jaundice
1) ABO incompatibility
- mOther has antibodies against bAby
2) Rhesus
- Rh-ve mother exposed to Rh+ve red cells during first pregnancy. In following pregnancy, she produces anti-D which breaks down child’s red cells = alloimmunisation
3) G6PD deficiency
- Lack of G6PD leads to rapid haemolysis during oxidative stress eg infection, medication, lava beans (X- linked recessive)
List some risk factors for neonatal jaundice (5)
1) Premature / low birth weight
2) Breast-fed babies
3) Diabetic mother
4) Male
5) East Asian ethnicity
How may physiological jaundice present?
Not apparent in first 24 hours, usually presents at 2-3 days
- Child remains well
- Serum bilirubin remains below treatment level
- Jaundice fades by 14 days
What investigations are done for neonatal jaundice?
1) Bilirubin level - transcutaneous bilirubinometer or serum bilirubin
2) LFTS - hepatitis or cholestatic disease
3) Infection screen - TORCH congenital infection screen, surface swabs, urine culture, blood culture, LP, CXR
4) Haemolysis = blood type, RH (mother and infant), reticulocyte count, direct Coomb’s test, Hb and haemaotcrit count, peripheral blood film for erythrocyte, red cell enzyme assays eg G6PD activity
5) Reducing substance in urine = screening test for galactosaemia (if infant has received sufficient quantities of milk)
6) TFTs
What is Coombs test?
Coombs test = tests for autoimmune haemolytic anaemia
Direct antiglobulin test (DAT): tests for antibodies directly bound to RBC. A blood sample is taken and RBC are washed (to remove patients own plasma and unbound antibodies). A anti-human globulin (antibody to antibodies) is then added, if the red cells then agglutinate = positive result (shows there are antibodies bound to the surface of RBC)
NB Indirect antiglobulin test (IAT): tests for antibodies circulating in the patients blood (this is a prenatal test)
What treatment can be done for neonatal jaundice?
Depends on cause. Give fluids and refer urgently if <24hr or unwell
1) Phototherapy
2) Exchange transfusion
How does phototherapy help neonatal jaundice? How effective is it?
Blue light converts unconjugated bilirubin to harmless water soluble products done via a combination of overhead lights and fibre-optic blanket
Very effective - after 4hrs, 20% of total bilirubin is in harmless form
What are some risks associated with phototherapy for neonatal jaundice?
Risk of hyper/hypothermia, worse attachment, loose stools
When is exchange transfusion required for neonatal jaundice? What are some risks?
Rarely required but indicated in severe hyperbilirubinaemia. Up to 2x blood volume replaced
Risk of thrombosis, embolism, infection, metabolic and coagulation abnormalities
What is Kernicterus?
= Bilirubin toxicity encephalopathy
Yellow staining of basal ganglia
How may Kernicterus present?
Hypotonia + lethargy
Followed by seizures, coma, and death
How should Kernicterus be treated?
Phototherapy
Birth asphyxia been renamed?
Hypoxic ischaemic encephalopathy (HIE)
What is HIE?
Supply of oxygen to the brain is compromised by both failure of gas exchange (hypoxia) and failure of cerebral blood supply (ischaemia)
What is the pathophysiology of HIE?
Foetal ischaemia leads to hypoxia, hypercapnia, metabolic acidosis and cardiorespiratory depression
Acute severe asphyxia can cause brain damage within 10-12 mins (HIE) and death within 20-30 mins
What are some antepartum causes of HIE? (3)
1) Inadequate maternal placental perfusion caused by hypotension or HTN
2) Foetal anaemia
3) IUGR
What are some intrapartum causes of HIE? (2)
1) Prolonged uterine contractions
2) Cord compression
How may HIE present?
Increased respiratory effort Apnoea Irregular gasping Bradycardia Hypotension
How is HIE graded? What features are included?
1 - 3
Alterness Muscle Tone Seizures Pupils (autonomic) Respiration (function) Duration
What is grade 1 HIE?
Alterness = hyperalert Muscle Tone = normal / increased Seizures = none Pupils (autonomic) = dilated and reactive Respiration (function) = regular Duration = <24hrs
What is grade 2 HIE?
Alterness = lethargy Muscle Tone = hypotonia Seizures = frequent Pupils (autonomic) = small and reactive Respiration (function) = periodic Duration = 2-14 days
What is grade 3 HIE?
Alterness = coma Muscle Tone = flaccid Seizures = uncommon Pupils (autonomic) = variable / fixed Respiration (function) = apnoea Duration = weeks
What often accompanies HIE?
Multiorgan dysfunction
What cardiac dysfunction may accompany HIE?
Hypotension
Arrhythmias
Shock
What renal dysfunction may accompany HIE?
Tubular or cortical necrosis
Oliguria
Haematuria
What GI dysfunction may accompany HIE?
GI bleeding
Gut ischaemia
NEC
Ileus
What metabolic dysfunction may accompany HIE?
Hypo / hyperglycaemia
Lactic acidosis
Hyponatraemia
What haemolytic dysfunction may accompany HIE?
DIC
What investigations should be performed for HIE?
Bloods - FBC, clotting screen, ABG (pH <7), LFTS, calcium, magnesium, creatinine, lactate, glucose
EEG (12-72hrs)
MRI
Apgar: 0-3 for >5mins
What is the apgar score?
Test given to newborns soon after birth
Activity (muscle tone) Pulse Grimace (reflex irritability) Appearance (skin colour) Respiration
How is the apgar score calculated?
0-2 points
What scores 0 points on the apgar score?
Activity (muscle tone) - absent Pulse - absent Grimace (reflex irritability) - floppy Appearance (skin colour) - blue / pale Respiration - absent
What scores 1 point on the apgar score?
Activity (muscle tone) - flexed arms and legs
Pulse - below 100 bpm
Grimace (reflex irritability) - minimal response to stimulation
Appearance (skin colour) - pink body, blue extremities
Respiration - slow and irregular
What scores 2 points on the apgar score?
Activity (muscle tone) - active Pulse - over 100 bpm Grimace (reflex irritability) - prompt response to stimulation Appearance (skin colour) - pink Respiration - vigorous cry
How are total apgar scores classified?
0-3 = need immediate resuscitation 4-6 = moderately depressed 7-10 = normal
What is the treatment for HIE?
Most recover quickly with prompt resuscitation
Cooling (to 33.5 degrees) to reduce brain damage
ET intubation - to give intermittent positive pressure ventilation (IPPV)
Circulatory support - IV arterial lines (compressions if severe bradycardia despite ventilation)
Medication:
- Adrenaline IV
- Sodium bicarb IV (combat acidosis)
- 10% dextrose if hypoglycaemic
- Volume expansion (saline or blood if hypovolaemia)
- If seizures: phenobarbital / phenytoin / clonazepam)
NB room air rather than 100% oxygen
What is the prognosis of HIE?
Mild = good outcome
Severe = 75% mortality
- 80% of survivors have neurological complications
Name three types of vascular birthmarks
1) Capillary haemangioma (straberry naevus)
2) Capillary malformation
3) Mongolian blue spot
4) Salmon patch
What is a bright red, lumpy, compressible, sharply demarcated lesion, which tends to enlarge until age 2-4 years then regresses spontaneously without treatment?
Strawberry naevus (superficial haemangioma)
How common is a strawberry naevus?
Very common esp in preterm infants
5% babies
When may treatment be required for a superficial haemangioma and what is this?
If it is near important structures eg airway / eyes
Propanolol injections can speed regression
Which vascular birthmark may be associated with a syndrome?
Portwine stain (capillary malformation) if localised to trigeminal region may be a sign of Sturge-Weber syndrome
What is present with Sturge-Weber syndrome?
An underlying meningeal haemangioma, intracranial calcification and fits
Describe the appearance of a portwine stain (capillary malformation)
Sharply circumscribed, macular, pink to purple lesions
= abnormal dilatation of normal dermal capillaries
What is the management of capillary malformations?
Do not resolve but some lesions can be improved with laser therapy
What is a blue/grey lesion in the sacral area?
Mongolian blue spot
Why is it important to document Mongolian blue spots in baby checks?
They can be confused with bruises
In which group are Mongolian blue spots more common?
Racial groups with pigmented skin (>80% of black and asian babies are born with them)
What is the course of a Mongolian blue spot?
Fade during early years
Name three pigmentation disorders
1) Pigmented naevus
2) Café au lait
3) Depigmentation
What is associated with neurofibromatosis?
Café au lait
Describe the appearance of café au lait spots
Uniformly pigmented, sharply demarcated, macular lesions
Can vary greatly in size
6 or more or >0.5cm indicates neuobifromatosis
Describe the course of café au lait spots
Can develop in increasing number and size throughout childhood
What is neurofibromatosis?
Genetic disorder that causes tumours to form anywhere in the nervous system
What syndrome is café au lait spots associated with?
McCune-Albright
What is McCune-Albright syndrome?
At least 2 of:
1) Polyostotic fibrous dysplasia (fibrous tissue in bones)
2) Café au lait spots
3) Autonomous endocrine hyperfunction eg gonadotropin-independent precocious puberty
What other systems may be implicated in those with café au lait spots?
Neurological and skeletal problems
What is a pigmented naevus called that develops:
1) From birth
2) During childhood
1) From birth = congenital naevus
2) During childhood = moles
What is a risk of a large pigmented naevus?
Risk of malignant change - may require surgical excision
What skin abnormality is seen genetic disorder tuberous sclerosis?
Depigmentation and pigmentation
What other abnormalities may be seen in skin depigmentation?
Brain abnormalities
Epilepsy
Learning difficulties
What is a salmon patch?
Naevus flemmeus
Small pink flat lesions occurring most commonly on eyelids, neck and forehead
Ones on face usually disappear completely
= Stork marks
What is the course of a salmon patch?
Most fade completely within a few months
But those on forehead can take up to 4 years to disappear
Often become more noticeable when the baby cries (fills with blood)
How common are salmon patches?
Most common type of vascular birth mark
Occurs in 50% babies
Describe the course of a portwine stain
Sensitive to hormones, may become more noticeable around puberty, pregnancy, menopause
Most are permanent and may deepen in colour over time
