Metabolic Bone Disease Prevention Protocol

 

Metabolic bone disease of prematurity is a common problem in preterm infants. The aim of this protocol is to assure that our NICU babies receive the recommended daily requirement of calcium, phosphorus and vit D necessary to prevent metabolic bone disease and promote good bone mineralization and growth.

It is important to recognize the biochemical signs of osteopenia in an early stage in order to be able to quickly implement the dietary intake and reduce the risk of bones fractures.

  Metabolic Bone Disease can remain silent until a severe demineralization occurs. The most evident clinical findings of rickets (severe osteopenia) are deformity of the skull (diastasis of the suture, enlargement of the sagittal fontanelle, frontal bossing and craniotabes), thickening of the chondrocostal junctions and of the wrists, rib and long bones fractures. Softening and/or fractures of the ribs can cause pulmonary changes and even respiratory distress.

 If MBD is diagnosed additional nutritional supplementation should be started and periodic assessment of laboratory data is necessary to evaluate the response to treatment.

 

Recommended  Guidelines:

 

Daily requirements:

    • Calcium (mg/kg/day):  100-160 mg/kg/day
    • Phosphorus: 60-90mg/kg /day
    • Vitamin D (IU/day): 400-600 IU/Day.  If infant is at high risk for vit D

      deficiency (see list below) daily requirement may increase up to 800-1000

      IU/day

    • When infants reach 80-100 ml/kg/day of enteral feeds Vit D supplements should be started at 400 IU/day

 

Weekly nutrition note will provide information regarding total amount of protein, fat, Ca, PO4 and vit D given to the baby. Residents and NNP will read these values when available on Tuesdays along with growth parameters.

 

Infants at risk of Vitamin D deficiency (daily requirement of Vit D is 800IU//day):

 

1.     Short Gut Syndrome (decreased absorption of vit D)

2.     Liver Disease/Cholestasis (decreased hydroxylation)

3.     Renal Disease (decrease conversion in kidney)

4.     Suspicion of rickets (bone fracture,  high alk phos level/low PO4)

5.     Infants on anticonvulsants

6.     Infants on chronic use of diuretics

7.     Dark skinned infants

8.     Parenteral nutrition for more than 4weeks

 

 

Indicators of Vit D deficiency:

Alkaline phosphatase (APA) level ≥ 800U/l

High APA and low serum PO4

Low Vit D level

Fractures

 

 Labs:

APA as well as serum Ca and Phos levels should be obtained at 1 month of age for the first time and then Q2weeks along with calcium and phosphorus if the infant is at risk of vit D deficiency (bundle with other labs to avoid repeated sticks for blood sampling).  If full feeds have been reached levels should be checked Q3-4 weeks.

 If there is a high suspicion of vit D deficiency a wrist and or knee X-ray should be considered to screen for signs of rickets.

Once levels of APA, calcium and phosphorus normalize, serum analysis can be performed bi-monthly up to 6 months of age and then every 3 months.

The key clinical goal is to maintain normocalcemia and normophosphatemia and to avoid an excessive calciuria.

Serum levels of 25-OH vit D might be checked if possible (no need to check 1-25 vit D –usually normal in vit D deficiency). The current blood test available at VCH requires 1ml of blood in red top tube (discuss with attending before ordering this test). If Vit D levels are obtained the following values should be interpreted:

 

Severe deficiency ≤ 12.5 nmol/L (≤5 ng/ml)

Deficiency: 12.5 - 37.5 nmol/L (5-15 ng/ml)

Insufficiency: 37.5 – 50 nmol/L (15- 20ng/ml)

Sufficiency: 50-200 nmol/L (20-80 ng/ml)

Excess: 250 - 375 nmol/L (100-150 ng/ml)

Intoxication: > 375 nmol/L (> 150ng/ml)

 

 

Treatment of Vit D deficiency:

  1. Optimize Vit D supplementation.
  2. Consider modifying therapies that can cause calcium losses (diuretics-may change to calcium sparing diuretic)
  3. When treating Vit D deficiency supplement phosphorus as needed to maintain serum   levels of 5.5-7.5 mg/dl.

 

Vit D supplements (preferred Vit D3) in our nicu include:

1. D-Vi-Sol which is 400 IU/1mL

Physical therapy: start at 32 weeks corrected GA

Infant needs to be at least 7 days old, clinically stable, and on full enteral feedings in order to be eligible for physical therapy.

 

At discharge:

 

 

BW ≤ 1500g

 

DW ≤2000g

DW >2000g

 

MBM

Preterm formula

BF exclusively

Not BF exclusively

Exclusively formula

Fortifier (NS powder) recommended

Yes

N/A

N/A

Yes

N/A

Vit D supplementation

400UI/day

200-400 UI/day

400UI/day

400 UI/day

200-400UI/day

APA

-

-

At 4 weeks postdischarge

-

-

 

 

BW ≤ 1500g

 

DW ≤2000g

DW >2000g

 

MBM

Preterm formula

BF exclusively

Not BF exclusively

Exclusively formula

Fortifier (NS powder) recommended

Yes

N/A

N/A

Yes

N/A

Vit D supplementation

400UI/day

200-400 UI/day

400UI/day

400 UI/day

200-400UI/day

APA

-

-

At 4 weeks postdischarge

-

-

 

References

Sarah N. Taylor, MD, Bruce W. Hollis, PhD. Vitamin D Needs of Preterm Infants. NeoReviews Vol.10 No.12 2009 e590

Valentina Bozzetti and Paolo Tagliabue. Metabolic Bone Disease in preterm newborn: an update on nutritional issues Valentina Bozzetti† and Paolo Tagliabue Italian Journal of Pediatrics 2009, 35:20

Fatih M. Kislal and Ugur Dilmen. Pediatrics International (2008) 50, 204–207 Effect of different doses of vitamin D on osteocalcin and vdeoxypyridinoline in preterm infants

Shannon M Mitchell1, Stefanie P Rogers. High frequencies of elevated alkaline phosphatase activity and rickets exist in extremely low birth weight infants despite current nutritional support. BMC Pediatrics 2009, 9:47

Holick, MF. Vit D deficiency. New England Journal of Medicine, 2007 357(3), 266-281 

Misra, M, Pacaud, D. Vitamin D deficiency in children and its management. Pediatrics 2008 122(2) 398-417

Steven A. Abrams and the COMMITTEE ON NUTRITION. Calcium and Vitamin D Requirements of Enterally Fed Preterm Infants. Pediatrics; 2013;