Rickets: Difference between revisions
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**Fortified foods (mainstay), supplements, fatty fish, egg yolks, fish liver oil, and some mushrooms | **Fortified foods (mainstay), supplements, fatty fish, egg yolks, fish liver oil, and some mushrooms | ||
**Synthesis of vitamin D occurs in the skin through exposure to ultraviolet B radiation from sunlight | **Synthesis of vitamin D occurs in the skin through exposure to ultraviolet B radiation from sunlight | ||
*Hydroxylated in | *Hydroxylated in liver→ 25-hydroxyvitamin D, which is further hydroxylated in kidney or extrarenally→ 1,25-dihydroxyvitamin D (active form) | ||
**Second hydroxylation regulated by PTH, serum calcium, and phosphorus levels | **Second hydroxylation regulated by PTH, serum calcium, and phosphorus levels | ||
*Vitamin D acts to: | *Vitamin D acts to: | ||
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*Generalized muscle [[weakness]] | *Generalized muscle [[weakness]] | ||
*[[Hypocalcemia]] | *[[Hypocalcemia]] | ||
*Growth disturbance | *[[failure to thrive (peds)|Growth disturbance]] | ||
*Enlarged and soft skull (craniotabes), long bones, joints of rib cage ("rickety rosary") | *Enlarged and soft skull (craniotabes), long bones, joints of rib cage ("rickety rosary") | ||
*Metaphyseal hyperplasia (double malleoli sign, widening of wrist) | *Metaphyseal hyperplasia (double malleoli sign, widening of wrist) | ||
*Bowed legs in toddlers (genu varum), knock-knees in older children (genu valgum) | *Bowed legs in toddlers (genu varum), knock-knees in older children (genu valgum) | ||
*Dental problems | *[[Dental problems]] | ||
==Differential Diagnosis== | ==Differential Diagnosis== | ||
*[[Hypocalcemia]] | *[[Hypocalcemia]] | ||
*Hyperparathyroidism | *[[Hyperparathyroidism]] | ||
*[[Hypophosphatemia]] | *[[Hypophosphatemia]] | ||
*Malignancy | *Malignancy | ||
Line 54: | Line 54: | ||
*Assess for fractures, if indicated | *Assess for fractures, if indicated | ||
*BMP, Mg/Phos, serum calcium | *BMP, Mg/Phos, serum calcium | ||
===Serum 25-hydroxyvitamin D=== | |||
''Vitamin D assessed by measuring this precursor to hormonally active 1,25-dihydroxyvitamin D'' | |||
*Normal range: 75-250 nmol/L | |||
*Insufficiency: 25-75 nmol/L | |||
*Deficiency: <25 nmol/L | |||
==Management== | ==Management== | ||
*Treat complications (e.g. [[hypocalcemia]], fractures, bone pain) | *Treat complications (e.g. [[hypocalcemia]], [[fractures]], [[analgesia|bone pain]]) | ||
*Supplemental vitamin D | *Supplemental vitamin D | ||
**Initial high-dosage treatment phase: 1,000 IU cholecalciferol per 10 nmol/L required serum increase given daily for 2-3 months | **Initial high-dosage treatment phase: 1,000 IU cholecalciferol per 10 nmol/L required serum increase given daily for 2-3 months |
Revision as of 16:45, 29 September 2019
Background
- Bone disorder characterized by soft, weak, and deformed bones
- Predominantly caused by Vitamin D deficiency or impaired vitamin D metabolism, but can also be due to hypocalcemia
- More common in areas with high rates of early childhood malnutrition/starvation
- The predominant cause is a Vitamin D deficiency, but also inadequate calcium and impaired metabolism of vitamin D may also lead to rickets
Metabolism and Physiology of Vitamin D
- Gained from diet, supplements, or sunlight exposure
- Fortified foods (mainstay), supplements, fatty fish, egg yolks, fish liver oil, and some mushrooms
- Synthesis of vitamin D occurs in the skin through exposure to ultraviolet B radiation from sunlight
- Hydroxylated in liver→ 25-hydroxyvitamin D, which is further hydroxylated in kidney or extrarenally→ 1,25-dihydroxyvitamin D (active form)
- Second hydroxylation regulated by PTH, serum calcium, and phosphorus levels
- Vitamin D acts to:
- Stimulate intestinal calcium absorption
- Maintain adequate phosphate levels for bone development
- Regulate cell growth proliferation and apoptosis
- Modulate immune function and inflammation reduction
Etiology of Vitamin D Deficiency
- Inadequate intake
- Maternal vitamin D deficiency: in utero, 25-hydroxyvitamin D passes through the placenta to the infant
- Exclusive breastfed infants without vitamin D supplementation
- Inadequate sunlight exposure, dark skin pigmentation
- Impaired vitamin D absorption
- Impairment in conversion of vitamin D into active metabolites
Types of Rickets
- Hereditary rickets
- Kidneys unable to retain phosphate
- Nutritional rickets
- Vitamin D Resistant Rickets
- Vitamin D Dependant Rickets
- Congenital Rickets
Clinical Features
- Peak incidence between 3 and 18 months of age
- Bony pain
- Generalized muscle weakness
- Hypocalcemia
- Growth disturbance
- Enlarged and soft skull (craniotabes), long bones, joints of rib cage ("rickety rosary")
- Metaphyseal hyperplasia (double malleoli sign, widening of wrist)
- Bowed legs in toddlers (genu varum), knock-knees in older children (genu valgum)
- Dental problems
Differential Diagnosis
- Hypocalcemia
- Hyperparathyroidism
- Hypophosphatemia
- Malignancy
- Nonaccidental trauma (if evidence of multiple acute or healing fractures)
Evaluation
- Assess for fractures, if indicated
- BMP, Mg/Phos, serum calcium
Serum 25-hydroxyvitamin D
Vitamin D assessed by measuring this precursor to hormonally active 1,25-dihydroxyvitamin D
- Normal range: 75-250 nmol/L
- Insufficiency: 25-75 nmol/L
- Deficiency: <25 nmol/L
Management
- Treat complications (e.g. hypocalcemia, fractures, bone pain)
- Supplemental vitamin D
- Initial high-dosage treatment phase: 1,000 IU cholecalciferol per 10 nmol/L required serum increase given daily for 2-3 months
- Maintenance: 400 IU daily
- Double dosage for premature infants, infants/children with dark pigmentation, children with limited sun exposure, and obese patients
- Some populations may require higher dosing (i.e. parathyroid disease, chronic liver disease, renal failure, and malabsorption disorders)