6. Rickets
O It is a disease of growing bone, unmineralized matrix at the growth plates
and occurs in children only before fusion of the
epiphyses.
O An increase in the circumference of the growth plate and the metaphysis,
increasing bone width at the location of the growth plates.
7. Causes
O VITAMIN D DISORDERS
Nutritional vitamin D deficiency
Congenital vitamin D deficiency
Secondary vitamin D deficiency
Malabsorption
Increased degradation
Decreased liver 25-hydroxylase
Vitamin D–dependent rickets type 1 A and B
Vitamin D–dependent rickets type 2 A and B
Chronic kidney disease
8. O CALCIUM DEFICIENCY
Low intake
Diet
Premature infants (rickets of prematurity)
Malabsorption
Primary disease
Dietary inhibitors of calcium absorption
O PHOSPHORUS DEFICIENCY
Inadequate intake
Premature infants (rickets of prematurity)
Aluminum-containing antacids
10. Clinical features
O GENERAL – Failure to thrive, Listlessness, Protruding
abdomen, Muscle weakness (especially proximal) &
Fractures
O BACK – Scoliosis, Kyphosis & Lordosis
O HYPOCALCEMIC SYMPTOMS – Tetany, Seizures &
Stridor due to laryngeal spasm
12. CHEST – Rachitic rosary, Harrison groove &
Respiratory infections and atelectasis
13. EXTREMITIES – Enlargement of wrists and ankles, Valgus or varus deformities, Windswept
deformity, Anterior bowing of the tibia and femur, Coxa vara & Leg pain
14.
15. Vitamin D Deficiency
Nutritional
O 1st two months of life no deficiency
O Sun – melanin
O These children have increased risk of
pneumonia and muscle weakness leading to
delayed motor development
17. Treatment
O 300,000 – 600,000 IU orally or intramuscularly 2-4 doses over 1 day OR
O 2000 – 5000 IU/day over 4 – 6 weeks
O Followed by daily 400 IU/day for < 1 year and 600 IU / day > 1 year
O Symptomatic hypocalcemia 20mg/kg of calcium chloride
O Calcitriol – 0.05 mcg/kg/day in case of symptomatic hypocalcemia
O Prevention – breast fed (400IU/day) & child (600IU/day)
18. Congenital Vitamin D Deficiency
O Maternal vitamin D deficiency
O Risk factors – poor dietary, inadequate exposure
to sun and closely placed pregnancies
O Predisposes to hypocalcemic tetany
O Treated with Vit D supplement, calcium and
phosphorus
19. Secondary Vit D Deficiency
O Liver (>90% dysfunction) and GI disorders (pancreatic
dysfunction)
O Drugs like - phenobarbital, phenytoin, isoniazid and rifampin by
activating cytochrome P450
O High dose of 25 D helps in better absorption 25-50mcg/day or
5-7 mcg/kg/day
O In case of increased degradation of Vit D long term
administration = 1000-4000IU/day
20. Vitamin D-dependent rickets type 1
O AR – 1α-hydroxylase defect
O These patients respond to long-term treatment
with 1,25-D (calcitriol). Initial doses are 0.25-2
µg/day, and lower doses are used once the rickets
has healed.
21. O Targeting a low-normal calcium concentration
and a high-normal PTH level avoids excessive
dosing of calcitriol, which can cause
hypercalciuria and nephrocalcinosis.
O Periodic assessment of urinary calcium
excretion, with a target of <4 mg/kg/day.
22. Vitamin D-dependent rickets type 2
O AR mutation in Vit D receptor
O 1,25-D increased
O Less likely to have rickets due to partially functional D
receptors
O 50-70% have alopecia
O Managed initially with high does of 1,25-D 2mcg/day ---- 50-
60mcg/day and calcium 1000 to 3000mg/day
23.
24. Chronic Kidney Disease
Therapy requires Calcitriol
Dietary phosphorus restriction and the use of
oral phosphate binders is as important as the
use of activated vitamin D
25. Calcium Deficiency
O Excellent sources of calcium – breast milk and formula
feed
O Intravenous nutrition without adequate calcium or
malabsorption in celiac disease, intestinal
abetalipoproteinemia, and after small bowel resection.
There may be concurrent malabsorption of vitamin D.
27. Treatment
O Elemental calcium 700mg/day – 1 to 3 years of
age
O 1000mg/day – 4 to 8 years of age
O 1300mg/day – 9 to 18 years
28. Phosphorus Deficiency
O Malabsorption (celiac disease, cystic fibrosis,
cholestatic liver disease), but if rickets develops,
the primary problem is usually malabsorption of
vitamin D and/or calcium.
O Isolated malabsorption of phosphorus long-
term use of aluminum-containing antacids.
31. Fibroblast Growth Factor-23
O Fibroblast growth factor-23 (FGF-23) is a
humoral mediator that decreases renal tubular
reabsorption of phosphate and therefore
decreases serum phosphorus.
O It is synthesized by osteocytes, also decreases the
activity of renal 1α-hydroxylase, resulting in a
decrease in the production of 1,25-D.
32. X-Linked Hypophosphatemic Rickets
O AD – Defective gene is on the X chromosome
O PHEX – PHosphate-regulating gene with homology to
Endopeptidases on the X chromosome
O Indirect role in inactivating FGF-23, defect in this gene
causes over production of FGF-23
O Rickets with involving lower extremities and poor growth
are the dominant features
33. Treatment
O Phosphorus supplementation is 1-3 g of elemental
phosphorus divided into 4-5 doses
O Calcitriol is administered 30-70 ng/kg/day divided into 2
doses
O Laboratory monitoring of serum calcium, phosphorus,
alkaline phosphatase, PTH, and urinary calcium, as well as
periodic renal ultrasounds for nephrocalcinosis
35. Autosomal Recessive Hypophosphatemic
Rickets
O Type 1 is an extremely rare disorder caused by mutations in the
gene encoding dentin matrix protein 1 (DMP1).
O Type 2 – mutations in the ENPP1 gene. Mutations in ENPP1
also cause generalized arterial calcification of infancy
O Treatment is similar to the approach used in XLH, although
monitoring for arterial calcification is prudent in patients with
ENPP1 mutations
36. Hereditary Hypophosphatemic Rickets
with Hypercalciuria
O AR – Sodium-phosphate cotransporter in the
proximal tubule (SLC34A3).
O Hypophosphatemia 1,25-D(stimulation)
intestinal absorption of calcium, suppressing PTH.
O Hypercalciuria ensues as a result of the high
absorption of calcium and the low level of PTH,
which normally decreases renal excretion of calcium.
37. O Hypophosphatemia, renal phosphate wasting, elevated serum
alkaline phosphatase levels, and elevated 1,25-D levels. PTH levels
are low
O Oral phosphorus replacement (1-2.5 g/day of elemental
phosphorus in 5 divided oral doses)
O Treatment of the hypophosphatemia decreases serum levels of
1,25-D and corrects the
hypercalciuria
38. Tumor-induced osteomalacia
O Overproduction of FGF-23 is more common in
adults than in children, where it can produce
classic rachitic findings.
O Most tumors are mesenchymal in origin and are
usually benign, small, and located in bone.
O Treatment is removal of the tumor
40. Fanconi Syndrome
O It is secondary to generalized dysfunction of the
renal proximal tubule.
O Hypophosphatemia caused by phosphate losses
and proximal renal tubular acidosis caused by
bicarbonate losses. Failure to thrive is a
consequence of both rickets and renal tubular
acidosis.
42. Rickets Of Prematurity
O 80% Calcium and Phosphorus transfer 3rd trimester
O Infants with a birth weight <1,000 g
O Rickets of prematurity occurs 1-4 month after birth.
O Infants can have nontraumatic fractures, especially of the legs,
arms, and ribs. Most fractures are not suspected clinically
43. O Rachitic respiratory distress >5 week after birth
O Early supplementation of Calcium, phosphorus, and vitamin D Prevention
O Parenteral nutrition is often necessary initially in very premature infants
O Increased mineral feedings should continue until the infant weighs 3-3.5 kg. These
infants should also receive approximately 400 IU/day of vitamin D via formula and
vitamin supplements.
44. Disorder Calcium Inorganic
Phosphor
us(pi)
PTH 25-(OH)D 1,25-
(OH)2D
Alk phos Urine Ca Urine
phosphoru
s
Vitamin D
deficiency
N,
DECREASE
D
DECREASE
D
INCREASE
D
DECREASE
D
DECREASE
D, N,
INCREASE
D
INCREASE
D
DECREASE
D
INCREASE
D
Chronic
kidney
disease
N,
DECREASE
D
INCREASE
D
INCREASE
D
N DECREASE
D
INCREASE
D
N,
DECREASE
D
DECREASE
D
Dietary pi
deficiency
N DECREASE
D
N,
DECREASE
D
N INCREASE
D
INCREASE
D
INCREASE
D
DECREASE
D
Tumor-
induced
rickets
N DECREASE
D
N N RELATIVEL
Y
DECREASE
D
INCREASE
D
DECREASE
D
INCREASE
D
Fanconi
syndrome
N DECREASE
D
N N RELATIVEL
Y
DECREASE
D
/
INCREASE
D
INCREASE
D
DECREASE
D/INCREA
SED
INCREASE
D
Dietary Ca
deficiency
N,
DECREASE
D
DECREASE
D
INCREASE
D
N INCREASE
D
INCREASE
D
DECREASE
D
INCREASE
D
46. O A Randomized controlled trial on safety and efficacy of
single intramuscular versus staggered oral dose
of 600000IU Vitamin D in treatment of nutritional rickets.
J Trop Pediatr. 2014 Jun;60(3):203-10. doi:
10.1093/tropej/fmt105. Epub 2014 Jan 8.
O Comparing the Effects of Two Feeding Methods on
Metabolic Bone Disease in Newborns with Very Low Birth
Weights. Glob J Health Sci. 2015 May 29;8(1):249-54. doi:
10.5539/gjhs.v8n1p249.