Neonatal Pathophysiology Flashcards
Respiratory Dysfunction
conditions that interfere with normal O2 and lung airation/expansion
Neonatal asphyxia (chemical)
Dec O2 and inc CO2 = accumulation of H+ = respiratory acidosis
Respiratory Acidosis
Accumulation of H+ caused by dec O2 and inc CO2
Neonatal asphyxia (anatomical)
Pulmonary blood vessels don’t open maintaining high PVR > persistant foetal circulation
Metabolic Acidosis
Body cells do not receive O2 > anaerobic metabolism occurs > increased lactic acid production > metabolic acidosis
Neonatal asphyxia steps (8)
- Respiratory Acidosis
- Persistant foetal circulation
- Metabolic acidosis
- Stress Response
- Hypoglycaemia
- Dec CO and Sufactant (Acidosis)
- Shock
- Cardiac Failure
neonatal asphyxia causes (5)
- Intrauterine asphyxia
- Respiratory distress syndrom/prematurity
- Maternal medicines that inhibit respiration
- Cardiorespiratory malformations/dysfunctions
- Airway obstruction
Respiratory distress syndrome process
- Small alveolar = reduced surface area + harder to inflate
- Lack of surfactant = inc surface tension = harder to breath
- Poor ventilation > ventilation/perfusion mismatch = body responds by maintaining high PVR
Transient Tachypnoea
- Retained fluid in lungs > insufficient clearance
Transient tachypnoea aetology (5)
- Sufactant immaturity
- Cesarean section
- Breech Delivery
- Birth Asphyxia
- Heavy maternal analgesia
Pneumothorax
Injury to pleural membranes allowing air to leak in to pleural space
Affected lung collapes: displaces position (and therefore functioning) of heart
Meconium Aspiration
- Passed before birth and inhaled in first gasping breaths
- Obstructed airway > no lung airation > pneumothorax or pneumonia possible
- Increased in 40+ neonates, breech, foetal stress
Pneumonia
Infection of respiratory system at before/during birth
Pneumonia risk factors
PROM
Chorioamnionitis
Low birth weight
Respiratory distress manifestations
Tachypnoea Dyspnoea ( Recession of chest wall, nasal flaring) Grunting Cyanosis Bradycardia
Congenital heart defects
- Anatomical anomaly > abnormal blood flow
Patent ductus areteriosos physiology
- May remain open for days/weeks
- Allows L>R shunting > inc pulmonary blood flow > pulmonary hypertension > cardiac failure
- in some cases bacterial endocarditis
Patent ductus arteriosis manifestations
- Tachypnoea
- Dysapnoea
- lethargy
- failure-to-thrive
- murmurs
Ventricular septal defects definition
Defect within interventricular septum causing incomplete separation (smaller defects asymptomatic and likely to close)
Ventricular septal defects effects
L > R shunting > inc pulmonary blood flow > pulmonary hypertension
Hypertrophy of ventricles
Ventricular septal defects manifestations
- Tachypnoea
- Dyspnoea
- FTT tachycardia
Atrial septal defects definition
incomplete septum of atria, may extend to ventricular septum and/or cuspoid valves
atrial septal effects physiology
L>R shunt that may:
inc pulmonary blood flow > inc pulmonarly hypertension > hypertophy/dilation of R ventricle
Cardiac failure
Atrial septal defect manifestations
Tachypnoea
Murmors
Mild cyanosis
Transposition of great arteries definition
Aorta arises from R ventricle and pulmonary trunk from L ventricle = 2 closed system that dont feed in to each other. initial survival dependant on foetal circulation
Transposition of great arteries manifestations
Cyanosis that is not relived by O2 therapy
Total anomalous pulmonary veins definition
pulmonary veins not connected to LA
O2 blood returned to RA
initial survival dependant on foetal cirulations
total anomalous pulmonary veins manifestations
cyanosis
dyspnoea
tachypnoea
Teratology of fallot (4)
- Large ventricular septal defect
- Overriding aorta (opens at ventricular defect and overrides RV)
- pulmonary stenosis
- RV hypertrophy
tetralogy of fallot implications
decreased O2 sats
- dec blood flow to pulmonary trunk (R>L shunt)
- dec return to LA
tetralogy of fallot manifestations
cyanosis
polycythaemia (inc haematocrit)
dyspnoea
hypoxic spells
Vitamin K deficiency definition
Normal in healthy neonate. decreased bacteria in gut that synthesise VitK. Intensifies in days following birth
Haemorrhagic disease of newborn
- Early: within 24h. association with maternal medicines
- Classic: 2-6d when VitK at lowest levels. decreased prothrombin activity and prolonged clotting times
- Late 2-12w. associated with hepatobiliary and GI disorders
Polycynthaemia definition
- Haematocrit >65%
- Inc erythropoises stimulated by:
- Intrauterine hypoxia
- Maternal hypertension/diabetes
- Genetic abnormalities
- Increased BV = Twin-twin transfusion
Polycynthaemia manifestations
- Asymptomatic
- Hypoglycaemia
- Hyperbilirubinaemia
- Lethargy
- Respiratory Distress
Anaemia definition
“Physiological Anaemia” normal after birht Hbf destruction.
“anaemia of prematurity”
lower levels of Hbf at birth
Pathological anaemia
- not associated with physiological/prem anaemia
- Rhesus or ABO incompatibility (“haematolotic anaemia”)
- Blood loss
- needs iron supplementation
Body fliud imbalances
Immaturity of renal system = neonate is suseptable to over-hydration and dehydration and hyponatraemia
Overhydration
- Low GFR > inc risk of overhydration
- risk highest in first 5 days
Dehydration
- limited ability to concentrate urine
- vomiting
- diarrhoea
- oedema
Hyponatremia definition
- Sodium deficiency (dilutional hyponatremia = water gain diluting Na+)
- Extracellular fluid becomes hypotonic > water movement (ECF >ICF) > increase in cell size
- brain cells effected most
Talipes definition
Congenital deformity in foot: developed at unusual angle
Talipes causes
- Chromosomal
- Positional
Developmental dysplasia of the hip
hip joint is dislocated or dislocatable or subluxed
developmental dysplasia of the hip causes
- Chromosomal
- hormonal
- positional
Neural tube defect clasifications
- Aencephaly
- Encephalocele
- Spina bifida
Anencephaly definition
no development of cranium and brain. failure of cranial and end of NT to close
Encephalocele definition
Extrusion of brain and meninges through scull, canual or facial bones fail to form
Spina Bifida definition
possible extrusion of meninges and spinal cord through vertebral column. Failure of vertebral arch to form/fuse usually in lumbar
Spina bifida occulta
failure of vertebral arch to form but no protusion of neurological structures.
Spina bifida Meningocele
protrusion of meninges only through vertebral column
Spina bifida myelomeningocele
protrusion of menenges and spinal cord through vertebral column
Hydrocephalus physiology
- blockage of CSF flow or defect in reabsorption of CSF in cranial cavity > Excess cranial volume of cerebrospinal fluid > expansion of the head > decreas in blood volume
hydrocephalus manifestation
expansion of head
increased crandial pressure implications
- Obstruct cerebra blood flow
- destroy brain cells
- displace brain cells
- damage brain structures
Dysfunctio of metabolism
Abnormal metabolism of any substance absorbed from the diet and/or excreted
Jaundice
Yellow discouloration of skin, sclera and mucous membranes due to deposition of bilurubin
Physiological jaundice causes
immaturity of neonatal liver and GI system (inc breastmilk and premature jaundice)
Pathological jaundice
- RBC incompatibility
- Bruising and Haematomas
- Polycynthaemia
- Infections
- Congenital hypothyroidism
- G6PD deficiency
Metabolism of bilirubin
heme pigment of haemoglobin > biliverdin > unconjugated bilirubin (lipid soluble) > conjugated in liver > gut > excretion
Hyperbilirubinaemia
Excess of bilirubin in blood > deposited in fatty tissue Unconjigated bilirubin bassess BBB
Hyperbilirubinaemia causes (3)
- Saturation of molecules that transport bilirubin
- Decreased excretion/inc reabsorption
- Increased production
physiological jaundice
- day 2-5
- sufficient feeding and bowel movements and hydration it will pass (liver catches up)
Breastmilk jaundice
factors in breastmilk that increase reabsorption of bilirubin
Pathological jaundice causes
- Haemolytic jaundice: ABO incompatibility and Rhesus immunisation
- Devoping in first 24h
- Potentially dangerous > inc risk of neurotoxicity
Hypoglycaemia
BGL <2.6mmol/L
Common problem in transition to neonate
Stored as glycogen and lipids, used readily for energy following removal of maternal supply
Hypoglycaemic manifestations
- Jittery
- irratibility
- high pitched cry
- lethargy
- Apnoea
- Seizures
Hypoglycaemia risk factors
- Poor feeding
- SGA/IUGR
- Maternal obesity
- Maternal diabetes
- Hypothermia
- Asphyxia
Hypoglycaemia treatment
FEEDING ASAP & REGULARLY
BGL measurements
Consultation
Phenylketonuria (PKU)
PKU present from incomplete breakdown of phenylalanine - RARE METABOLIC DISORDER
phenylalanine accumulates and is deposited in tissues by blood and can lead to mental retardation , microcephaly and delayed neural development
Hypospadias
Proximal opening of urethra on penis
undecended testes
usually occurs in 3rd trimester.
willeventually affect sperm production
surgery req’d
Hyperthyroidism
thyroid gland enlarged > may make NVB difficult. usually transient
hyperthyroidism manifestations
increased BMR =
- tachycardia
- irritability
- low birth weight
- hunger
- advanced bone age
Hypothyroidism
most commonly caused by dysgenesis of thyroid gland
maternal production will compensate to a degree in utero, symptoms presenting later
Congenital adrenal hyperplasia
Defect in cortisol synthesis > inc levels of ACTH > adrenal hyperplasia > overproducion of cortisoid precursers
Cleft lip/palete
occur due to failure of fusion during early embryological development due to
nasomedial processes withmaxillary process
palatal shelves
chromosomal and teratogenic link
Oesophageal atresia
proximal and distal of oesophagus are not connected (piece missing)
Exomphalos
protrusion of abdominal contents within sac of amniotic membrane/pentoneum through umbilicus.
Associated with heart and kidney problems
Gastroschisis
protrusion of abdominal contents without any sac thruogh abdominal wall
Caput
oedema and bruising of soft tissue of presenting part resolves in a few days
Chignon
oedema, bruising and skin damage following vacuum extraction resolves in a few days
Cephalohaematoma
bleeding below periosteum confined within margins of sutures. worse at day 2, resolves over several weeks. may exacerbate jaundice
Forcep marks
heal rapidly
Skull fracture
usually perietal bone. may req surgery
fractured clavical
SD and breech. surgery may be req’d
Facial palsy
damage to nerves of brachial plexus due to traction on neck or arm. Erbs palsy (arm) and Klumpke’s palsy (wrist)
