Rickets and Vitamin D Deficiency
From Guide to YKHC Medical Practices
(adapted from PowerPoint Presentation by Drs. Lescher and Singleton)
Pathophysiology:
- Failure of mineralization of growing bone and cartilage
- A state of extreme vitamin D deficiency
- Peak incidence between 3 and 18 months of age
Risk Factors:
- insufficient dietary intake and sun exposure
- darker skin color and use of sunscreen
- breastfeeding exclusively without Vitamin D supplementation
- Northern Latitudes (above 37 deg Latitude)
- Anticonvulsants, Antifungals, glucocorticoids
- Limited intake of foods high in Vitamin D (very few exist naturally; however, the Native diet is high in Vitamin D, but the number of children on an exclusive Native diet is decreasing)
- Obesity
Signs/Symptoms:
- Irritability, pain, gross motor developmental delay, poor growth
- Widening of the wrists and ankles, Genu varum or valgum, Prominent costochondral junction (rachitic rosary), Delayed closure of fontanels, Craniotabes, Frontal bossing
- Delayed tooth eruption, increased risk of caries
- Increased susceptibility to infections
- Severe hypocalcemia—tetany, seizures (more often infancy or adolescence with increased growth velocity). usually asymptomatic until serum Ca<7.5mg/dl
Diagnosis:
- Radiologic studies: Wrist or Knee XRays
- Osteopenia, cortical thinning of long bones
- Stress fractures
- Metaphyseal widening and fraying, splaying, cupping
- Laboratory studies: Alk Phos is a good screen for rickets; 25OHD level is needed for assessment of Vitamin D status
- Hypophosphatemia, varying degrees of hypocalcemia
- Increased alkaline phosphatase
- Increased PTH
- Low 25OHD levels
Management:
- Replace vitamin D and calcium (Proposed treatment plans by AAP):
- Pharmacological doses of vitamin D: 1000-10,000 IU per day for 8-12 weeks depending on age of the child, then maintain at 400-1000 IU per day
- 1000-5000 IU/day up to age 1, >5000 IU/day after age 1
- Stoss therapy: 100,000 – 600,000 IU vitamin D orally, over 1-5 days, then maintain at 400-1000 IU vitmain D per day or 50,000 IU vitmain D2 weekly for 8 weeks (teens and adults only)
- Calcium: 30-75 mg/kg/day elemental Ca in 3 divided doses (start at higher dose, then wean down to lower end of the range over 2-4 weeks
- May also need Calcitriol (1,25D) if hypocalcemic
- Pharmacological doses of vitamin D: 1000-10,000 IU per day for 8-12 weeks depending on age of the child, then maintain at 400-1000 IU per day
- Monitoring of therapy (proposed, by AAP)
- At 1 month: measure Ca, Phos, Alk Phos
- At 3 months, measure Ca, Phos, Mg, Alk Phos, iPTH, 25OHD, urine Ca/Cr and recheck X-rays
- At 1 year and annually, measure 25OHD
- If symptomatic from severe hypocalcemia
- Slow (<1 ml/min) IV infusion 10% Ca gluconate 1 ml/kg
- 100 mg/ml Ca Gluconate = 9 mg/ml elemental Ca
- Cardiac monitoring (bradycardia, shortened QTc due to IV Ca); close attention to infusion site if not central IV (risk of tissue necrosis if peripheral IV infiltration)
- If Mg low, replace with 0.1-0.2 ml/kg 50% Mg Sulfate
- Slow (<1 ml/min) IV infusion 10% Ca gluconate 1 ml/kg
Critical Times for Affected Patients (When to refer to Endocrinology):
- If no healing after 3 months of Vit D and Ca replacement
- Concern for malabsorption, liver disease, adherence
- When considering other causes of rickets (not Vit D deficiency)
- Rickets <6 months old or between 3 and 10 years old
- Xrays that show periostal reaction and moth-eaten metaphysis rather than splaying, cupping, etc.
- Normal levels of AlkP, 25OHD, very low or very high levels of 1,25OHD, high BUN and Cr
- Severe hypocalcemia
Resources:
- Vitamin D Supplementation and Screening for the Prevention of Rickets and Osteomalacia in Alaska Recommendations from the Alaska Vitamin D Workgroup [1]
- Singleton, R. et al. Rickets and Vitamin D Deficiency in Alaska Native Children. J Pediatrc Endocrinol Metab. 2015 Jun: 28(0): 815-823. doi: 10.1515/jpem-2014-0446.
- Rickets and Vitamin D Deficiency in Children Powerpoint Presentation by Drs. Lescher and Singleton