Vitamin K

Question 1

What is the timing of late onset hemorrhagic disease of newborn

Answer 1

3-8 weeks of life (as early as 1 week)

Question 2

Is oral vitamin K equally effective as IM vitamin k?

Answer 2

AAP and CPS both say no

Relative risk of HDNB IM versus 1 PO dose - 13.8 (8.5 if you eliminate kids with liver disease)

In Germany they give the IV formulation orally in three doses every four weeks until three months.
Concerns re practicalities of this.

Question 3

What population is at increased risk of HDNB?

Answer 3

Breast fed babies (poor source of vitamin k in beast milk)

Other risk factors: malabsorption, CF, antibiotics, liver disease

Consider vitamin k deficiency in a bleeding baby during the first six months of life.

Question 4

Who would you consider a repeat dose of IM vitamin K?

Answer 4

Failure to thrive
Liver disease
Long term diarrhoea

Question 5

Would you ever give oral vitamin K?

And what is the dose?

Answer 5

If parents refuse IM vitamin k proving oral x 3 doses

2mg po with first feed at 0 4 and 6 weeks

Question 6

What is the risk of Intracranial hemorrhagic in HDNB

Answer 6

50% in late onset HDNB

Question 7

What is the dose of IM vitamin K

Answer 7

BW > 1500g 1 mg IM

BW

Question 8

Any complications of vitamin K IM?

Answer 8

No serious

Parental anxiety and pain

Question 9

What should you think of if baby is presenting with HDNB in the first 24 hours.

Answer 9

Mom on phenytoin and phenobarbital. These kids present in the first 24 hours. (Ie early HDNB)

Question 10

Why do babies need vitamin K given to them?

IE what is the pathophysiology of HDNB

Answer 10

Do not receive free vitamin K from mom.
Absence of bacterial intestinal flora responsible for synthesising vitamin K
So you get a moderate decrease in factors II VII IX X by 48 - 72 hours

Vitamin K facilitates post-transcriptional carboxylation of factors. Without K the factors for PIVKA which you can measure.

In late onset HDNB, you maybe have vitamin K malabsorption from hepatitis and biliary atresia for example.

Question 11

What investigations would you do in a newborn bleeding from suspected Vitamin K

Answer 11

Long PT and PTT
Decreased prothrombin. And factors (X IX VII) 
CBC
Apt test  in gi blood
PIVKA 
HUS

Question 12

What does early hemorrhagic disease of newborn look like?

Answer 12

Classically within the first week of life

Prodrome of mild bleeding –> bleeding with circumcision, mucosa bleeds, subgaleal, IVH

Question 13

When is early onset hemorrhagic disease? And what are the risk factors?

Answer 13

Within 24 hours

RF - mom on antibiotics, anti epileptics

Treat: treat mom prior to delivery

Question 14

What is the timing of classic HDN?

Answer 14

1-7 days