Chem Path: Paeds clinical chem Flashcards

1
Q

What are some common problems in low birth weight

A
Respiratory distress syndrome (RDS)
Retinopathy of prematurity (ROP)
Intraventricular haemorrhage (IVH)
Patent ductus arteriosus (PDA)
Necrotising enterocolitis (NEC)
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2
Q

What is NEC

A

Inflammation of bowel wall leading to necrosis and perforation

bloody stool
Abdo distension 
Pneuomatosis intestinalis (intermural gas)
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3
Q

When do nephrons develop in fetus?

A

Nephrons develop from about week 6 gestation

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4
Q

When does the foetus start producing urine?

A

They start producing urine from week 10

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5
Q

When does the Full complement of nephrons start?

A

36 weeks

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6
Q

Is the GFR in babies high and low and why?

A

LOW as babies have a high surface area

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7
Q

Why are babies prone to acidosis?

A

Low GFR - Low amount of Na available for H+ exchange

Short proximal tubule - Low reabsorbive capacity - Absorption of HCO3 is low

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8
Q

Is the threshold for gylcosuria higher or lower than adults in bebes?

A

Lower

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9
Q

Is the maximum urine osmolality higher or lower than adults for kids and why?

A

Lower

Kids - 700mmol/Kg

Adults - 12500mmol/Kg

Loop of Henle is short

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10
Q

Distal tubule is unresponsive to aldosterone - what are the consequences?

A

Persistant Na loss

Reduced K+ excretion

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11
Q

What is the upper normal limit of K+ in adults and kids?

A

Adults - 5.5

Kids - 6

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12
Q

Why do babies lose weight in the first week of life?

A

They have a lot of ECF as foetuses. After pulmonary resistance goes down post birth, ANP is released and there is redistribution of ECF.

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13
Q

What should be measured daily in babies born < 30 weeks?

A

Na due to increased Na demand coupled with Na loss in kidneys

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14
Q

Can you measure Na loss via urine in pre term babies?

A

NO

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15
Q

When can you give K+ supplement to babies?

A

Only after a urine sample is achieved (>1mL/kg/hour)

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16
Q

Why is bicarb given to babies and how does it cause electrolyte disturbances?

A

For acidosis

There is Na in it and their kidneys cannot excrete it

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17
Q

Why is caffeine/theophylline given to babies and how does it cause electrolyte disturbances?

A

For apnoea

Increases renal Na loss

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18
Q

Why is indomethacin given to babies and how does it cause electrolyte disturbances?

A

For PDA

Causes oliguria

19
Q

When is hyperNa common in kids?

A

In the first 2 weeks of life

20
Q

What should you consider for hyperNa occurring in kids after 2 weeks of birth?

A

Salt poisoning

21
Q

What measurements should you do for salt poisoning?

A

Urea, creatinine and electrolytes on paired urine and plasma

22
Q

What happens in congenital adrenal hyperplasia (CAH)

A

Lack of aldosterone production leading to salt loss and hypoNa

23
Q

What else happens in CAH?

A

Hypoglycaemia due to lack of cortisol

24
Q

What happens to sex steroids in CAH and how does it present?

A

High levels of pregnenolone

Presents in females with ambiguous genitalia

Growth acceleration

25
Q

Why is there hyperbilirubinaemia in neonates?

A

Increased RBC breakdown as foetal Hb gets destroyed

Enhanced enterohepatic circulation - increased reabsorption of bile

26
Q

What can be a complication of hyperbilirubinaemia?

A

Kernicterus - Bilirubin that crosses the BBB and has neurological defects

27
Q

What are the bilirubin levels for exchange transfusion and phototherapy in term babies and pre term babies and why is it lower for pre term babies?

A

Exchange transfusion - 450 (term) and 230 (preterm)
Phototherapy - 350 (term) and 120 (preterm)

Lower for pre term babies as albumin levels are lower and the BBB is leakier

28
Q

What are the other causes of hyperbilirubinaemia?

A

Haemolytic diseases
G6PD deficiency
Crigler-Najjar syndrome - Deficiency of bilirubin conjugation

29
Q

What is prolonged jaundice?

A

> 14 days in term babies

>21 days in preterm babies

30
Q

Why can there be prolonged jaundice in babies?

A

Prenatal infection / sepsis
Hypothyroidism
Breast milk jaundice

31
Q

Why can you have conjugated hyperbilirubinaemia?

A
Biliary atresia 
Ascending cholangitis with TPN
Galactosaemia 
Alpha 1 anti trypsin
Tyrosinaemia 1
Peroxisomal disorders
32
Q

What happens to calcium levels in babies when they are born?

A

It falls

33
Q

Is calcium or phosphate higher in babies?

A

Phosphate

34
Q

What happens to babies with hypocalcaemia and low phosphate

A

Osteopaenia of prematurity

35
Q

What would see on the CXR of a child with Osteopaenia of prematurity?

A

Fraying
Splaying
Cupping of long bones

36
Q

If Osteopaenia of prematurity is left untreated, what can you see?

A

Flailed chest and respiratory difficulties

37
Q

What is the biochem of Osteopaenia of prematurity?

A

Calcium is the last to change
PO4 low
ALP > 1200

38
Q

How to treat Osteopaenia of prematurity?

A

PO4 and calcium given separately

OR

1 alpha calcidol

39
Q

How can rickets present?

A

Bowed legs, frontal bossing, muscular hypotonia
May get abdominal laxity
Tetany/ hypocalcaemic seizures
Hypocalcaemic cardiomyopathy

40
Q

How can transient hypophosphataemia be differentiated from rickets?

A

Very high ALP

electrophoresis

41
Q

What is pseudo vit D deficiency type 1?

A

defective renal hydroxylation

Treated with 1,25 OH Vit D

42
Q

What is pseudo vit D deficiency type 2?

A

Defective receptor

Treated with 1,25 OH Vit D

43
Q

What is familial hypoPO4 caused by?

A

Low tubular maximum reabsoprtion of PO4

Raised urine phosphoethanolamine