Difference between revisions of "Rickets"

(Background)
 
(5 intermediate revisions by 4 users not shown)
Line 1: Line 1:
 
==Background==
 
==Background==
*Rickets is a bone disorder characterized by soft, weak, and deformed bones
+
*Bone disorder characterized by soft, weak, and deformed bones
*Origin of the word 'rickets' is from the word 'wrickken', to twist
+
*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
 
*The predominant cause is a [[Vitamin D deficiency]], but also inadequate calcium and impaired metabolism of vitamin D may also lead to rickets
*Rickets is one of the most frequent childhood disease in many developing countries
+
===Metabolism and Physiology of Vitamin D===
**Severe malnutrition from famine or starvation in early childhood
+
*Gained from diet, supplements, or sunlight exposure
*Vitamin D is important because it helps in the absorption of calcium and phosphate, minerals responsible for the strength and hardness of bones
+
**Fortified foods (mainstay), supplements, fatty fish, egg yolks, fish liver oil, and some mushrooms
*This disease occurs in children (term used for adults is [[Osteomalacia]]
+
**Synthesis of vitamin D occurs in the skin through exposure to ultraviolet B radiation from sunlight
*Risk factors for [[Vitamin D deficiency]] in infants include:
+
*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  
 
**Exclusive breastfed infants without vitamin D supplementation  
**Dark skin pigmentation  
+
*Inadequate sunlight exposure, dark skin pigmentation
**Maternal [[Vitamin D deficiency]]
+
*Impaired vitamin D absorption
***In utero, 25-hydroxyvitamin D passes through the placenta to the infant
+
**[[Crohn's disease]], [[cystic fibrosis]]
 +
*Impairment in conversion of vitamin D into active metabolites
 +
**[[Renal Failure]], [[Liver failure]]
  
==Types of [[Rickets]]==
+
===Types of [[Rickets]]===
*Hereditary rickets is an inherited form of the disease
+
*Hereditary rickets
**Kidneys are unable to retain phosphate
+
**Kidneys unable to retain phosphate
 
*Nutritional rickets
 
*Nutritional rickets
 
*Vitamin D Resistant Rickets
 
*Vitamin D Resistant Rickets
Line 23: Line 35:
 
==Clinical Features==
 
==Clinical Features==
 
*Peak incidence between 3 and 18 months of age
 
*Peak incidence between 3 and 18 months of age
*Enlarged and soft skull (Craniotabes)
+
*Bony pain
*Enlarged joints of long bones
+
*Generalized muscle [[weakness]]
*Enlarged joints of the rib cage (aka "rickety rosary"
+
*[[Hypocalcemia]]
*Double malleoli sign due to metaphyseal hyperplasia
+
*[[failure to thrive (peds)|Growth disturbance]]
*Widening of wrist due to metaphyseal cartilage hyperplasia
+
*Enlarged and soft skull (craniotabes), long bones, joints of rib cage ("rickety rosary")
*Curvature of the spine and femurs
+
*Metaphyseal hyperplasia (double malleoli sign, widening of wrist)
**Bowed legs in toddlers (Genu varum)
+
*Bowed legs in toddlers (genu varum), knock-knees in older children (genu valgum)
**Knock-knees in older children (Genu valgum)
+
*[[Dental problems]]
*Generalized muscle weakness
 
*Bony pain or tenderness
 
*Dental problems
 
*Growth disturbance
 
*Hypocalcemia
 
**Tetany
 
  
 
==Differential Diagnosis==
 
==Differential Diagnosis==
 +
*[[Hypocalcemia]]
 +
*[[Hyperparathyroidism]]
 +
*[[Hypophosphatemia]]
 +
*Malignancy
 +
*[[Nonaccidental trauma]] (if evidence of multiple acute or healing fractures)
  
 
==Evaluation==
 
==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==
 
==Management==
*Prevention key:
+
*Treat complications (e.g. [[hypocalcemia]], [[fractures]], [[analgesia|bone pain]])
**For healthy infants, children, and adolescents recommend a vitamin D intake of at least 400 IU/day
+
*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)
  
 
==Disposition==
 
==Disposition==
  
 
==See Also==
 
==See Also==
 +
*[[Vitamin D deficiency]]
  
 
==External Links==
 
==External Links==
Line 54: Line 78:
 
==References==
 
==References==
 
<references/>
 
<references/>
 +
 +
[[Category:Orthopedics]] [[Category:Pediatrics]] [[Category:FEN]]

Latest 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

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)

Disposition

See Also

External Links

References