Chempath - paediatric chemistry Flashcards
list common problems in LBW babies
RDS ROP IVH PDA NEC
features of NEC
inflammation of bowel wall progressing to necrosis and perforation
bloody stools
abdominal distension
intramural air (pneumatosis intestinalis)
how do neonatal kidneys differ to adult ones
low GFR to surface area - slow excretion of solute load, limited Na+ available for H+ exchange
short proximal tubule - lower resorptive capacity, lower threshold for glycosuria, worse reabsorption of bicarb - acidosis
short LOH/ DCD - reduced concentration ability
distal tubule relatively unresponsive to aldosterone - persistent loss of sodium and reduced potassium excretion (6 normal)
when do neonatal kidneys function
nephrons develop week 6
produce urine week 10
fully competent nephrons from 36 w
functional maturity of GFR - 2 years
why do all babies lose weight 1st week of life
redistribution of fluid
up to 10% of birth weight
why is there a high insensible water loss in neonates
high surface area
increased skin blood flow
high metabolic and RR
increased transdermal fluid loss
what drugs in neonates may cause electrolyte disturbance
bicarb for acidosis - contains high Na+
antibiotics - usually sodium salts
caffeine/ theophylline - increases renal sodium loss
indomethacin (for PDA) - oliguria (reduced urine output)
causes of hypernatraemia in neonates
uncommon after 2w
associated with dehydration/ overly concentrated milk formula
causes of hyponatraemia in neonates
1st 4-5 days:
- excessive intake
- SIADH secondary to infection or IVH (rare)
after 4-5 days:
- immature tubular function in patients on diuresis
CAH - addisonian presentation
- 21-hydroxylase deficiency
- reduced cortisol and aldosterone
- high androgens
clinical features of CAH
hyponatraemia hyperkalaemia volume depletion hypoglycaemia ambiguous genitalia growth acceleration
causes of prolonged jaundice
> 14 days term
days preterm
perinatal infection/sepsis
hypothyroidism
breast milk jaundice
calcium and phosphate in neonates
laid down in 3rd trimester
phosphate higher in babies
osteopenia of prematurity (fraying, splaying, cupping of long bones) - calcium normal, phosphate low, high ALP, treat with phosphate/calcium supplements
presentation of rickets
frontal bossing bowlegs/ knock knees muscular hypotonia tetany/ hypocalcaemic seizures hypocalcaemic cardiomyopathy
list genetic causes of rickets
pseudo- vit D deficiency
familial hypophosphateamias
