2. Vitamin D deficiency Rickets
(Nutritional Rickets)
Classically, Vita D deficiency predominantly causes
defect on bones, i.e. rickets in growing infants and
children before closure of epiphysis.
Osteomalacia is characterized by spongy trabecular
bones also resulting from demineralization as a
consequences of vitamin D deficiency, but after the
closure of epiphysis. i.e. in adults.
(Osteoporosis is due to proportionate loss of bone
volume & mineral, which is in children is often caused
by excessive administration of corticosteroids)
3. Vitamin D
Vitamin D, a secondary steroid, plays an important role in
calcium and phosphorus homeostasis,comprises a family of
fat soluble vitamins.
when deficient in diet,causes rickets from defective
mineralization of growing bone and osteomalacia in non
growing bone.
Vitamin D is absorbed in the small intestine, mainly in
duodenum by an active transport.
The ultraviolet rays of the sunlight are responsible for
converting the 7-dehydroxycholesterol( normally present
under the skin) in to Vit D3 or cholecalciferol.
4. Vit D3 or cholecalciferol, further converted in to 25
hydroxycholecalciferol in liver.
25 hydroxycholecalciferol is then converted to 1,25
dihydroxycholecalciferol in kidney
In the intestine vit D induces a calcium transport system
involving transport protiens and intracellular Ca binding
protein(CBP)
In the kidney vit D enhances Ca reabsorption in the tubule by a
mechanism similar to that in gut.
In bone, reabsorption of bone Ca to maintain Ca level in
blood.
5. Mechanism of Activation of VitaminD
Sunlight
(u. v. rays)
Skin(Inactive form of vit D/ 7-
dehydroxycholesterol)
7dehydroxycholesterol converted into Vit
D3 or cholecalciferol
Liver
(1st hydroxilation) 25
hydroxycholecalciferol
Kidney
(2nd hydroxilation)1,25
Dihydroxycholecalciferol
{Active form of vit D}
6. SOURCES OF VIT D
Most food contain only small amount of preformed
Vit D. Fish,liver and oils are good sources.
Human milk contains only 30-40 IU/L.
In addition to dietry sources,photoconversion by the
action of sunlight in ultraviolet band is an important
source of vitamin D for infants and children.
It is estimated that an infant needs to have about
20cm squ. Of skin exposed to sun light for 15-20 min
in order to synthesise enough vit D to prevent rickets.
7. Vitamin D Requirement
Produced endogenously in the skin.There is no
nutritional requirement of vit D when suffiicient
sunlight is available.
If not then, recommended daily dose in infants is 5
micro gm(200IU) per day and in children 10 micro
gm(400 IU) per day.
8. Deficiency Causes
Absense of sun light exposure.
Decreased synthesis by skin.
Liver failure
Kidney failure
Fat mal absorption syndrome
Biliary atresia
Cholestatic jaundice(obstructive jaundice).
Drug Induced- Antiepileptics,Rifampicin,INH.
9. SIGN & SYMPTOMS OF RICKTS
General symptom
Failure to gain wt. & hight.
Generalised muscle weakness.
Delayed dentition.
Delayed milestones.
Flat feet.
Pot belly.
Head
Open fontanale/Delayed closure.
Softening of skull bones known as craniotabes.
Frontal bossing(prominent frontal bone)
10. Thorax
Protuberance at costochondral junction called
rachitic rosary.
Depression at lower costal margin known
Harrison sulcus or groove.
Pigeon chest(pectus carinatum)
Recurrent chest infection.
Extremities
Widening of wrist joint.
Leg pain.
Lower limb deformity.
11. a) Genu valgum(knock-knees) in older children.
b) Genu varum(Bowed legs) in toddelers.
Double malleoli d/t metaphyseal hyperplasia.
15. Diagnosis
1.Biochemical:
Raised alkaline phosphatase(except in malnourished
children in whom this may be normal).
Usually normal or somewhat low serum calcium and
reduced phosphorus.
Today,reduction in the serum 25-hydroxyvitamin D3
level(<10 microgm/ml)is considerd a sensitive and
reliable index of rickets even in mal nourished
children,this is the only way to diagnose subclinical Vit
D deficiency.
16. 2. Radiological:
Radiological findings are best seen in at the
wrist,i.e. lower ends of radius and ulna.These
includes:
Cupping(saucer like concave depression)
The osteoid(matrix-mineralisation),being
radiotransluscent is not seen.In fact the space normally
occupied by mineralised matrix, is empty.
Flaring(widening):Everted(out-turned edges).
Fraying(rarefaction): Irregular tooth brush like
margins(bottom of the cup)
20. Treatment
Specific treament:
stoss therapy consists of administering a single
massive dose of vitamin D3(3,00,000 units up to 1 year
of age;6,00,000 units for later ages) orally or I.M.
together with supplimentry calcium & phosphorus.
Though serum alkaline phosphate and phosphorus tend
to return normal within just 5 days.
Initiation of radiological evidence in the form of
appearance of a linear shadow of provisional zone
of calcification in 10-14 days with further healing by 3-
4 weeks.
21. Prognosis
As a rule,response to pharmacotherapy is
gratifying,however in occasional child ,a poor response to
adequate doses of vitamin D3 encountered.
In such a case scenario, probability of refractory or
ressistent rickets should be considerd & the child
investigated for following conditions:
i. Malabsorption state,eg. Celiac disease, Tropical sprue
syndrome,cystic fibrosis.
ii. Renal rickets- chronic renal disease & renal tubular
acidosis (Fanconi syndrome)
iii. Prolonged anticonvulsent therapy.
iv. Cronic liver disease.
v. Hereditary vit D dependent rickets.
vi. Onchogenic rickets.
22. Prevention
Availability of at least 400 IU(not 200 as was earlier)of vitamin
D through sunshine,diet or suppliment must be ensured.
Now it is a standard practice to supplement all the
infants in the first year of life with 400 IU of vitamin D.
Health education to parents against over clothing the infants
and young children.
23. SOME OTHER TYPES OF RICKETS
1. VITAMIN D Dependent rickets(VDDR)
Rare autosomal recessively inherited rickets.
Seen in infants b/w age 3 to 6 months,who have been
receiving the usual amount of Vit D.
2 Forms are seen
VDDR TYPE 1 VDDR TYPE 2
24. VDDR TYPE 1 VDDR TYPE 2
•Deficiency of enzyme 25
hydroxyvitamin D-1-Alfa Hydroxylase.
•Blood level of 25(OH)D3 are normal but
those of 1,25 dihydroxy D3 are markedly
decreased.
•C/F are same as Vit D deficiency
rickets and include hypotonia growth
failure motor retardation (Poor head
control,Delayed Standing and Walking).
•The treatment of VDDR TYPE 1
Alfacalcicidol or calcicitrol ( 1 to 2
microgms daily) with Ca ,with or without
phosphorus.
•The features are similar to VDDR TYPE 1.
•There is end organ ressistance to 1,25
dihydroxy D3.
•This leads to virtual abolition of actions of
1,25 dihydroxy D3, despite its markedly
raised levels in circulation.(secondary to
hypocalemia and low 24-hydroxylase
activity).
•Early onset of rickets,high prevalance of
alopecia and ectodermal defect.
•The response to treatment in patients is not
satisfactory.
25. 2.Renal Tubular Acidosis
• Proximal as well as distal renal tubular acidosis (RTA)
are important causes of refractory rickets in children.
• Appropriate correction of acidosis with bicarbonate
suppliments and phosphate supplimentation results in
healing of rickets.
26. 3. Cronic Kidney Disease
• Refractory rickets may occasionaly be the presenting
manifestation of chronic kidney disease.
• c/f of osteodystrophy depend upon the patient age and
duration of disease.
• Elevated blood levels of creatinine and phosphate are
characterstic.
• Therapy consists of restricting of phosphate intake and
providing supplements of Ca and active Vit D analogs.
27. 4.Oncogenous Rickets
• Rarely benign mesenchymal tumors may secrete a
circulating sustance that results in
phosphaturia,hypophosphatemia,rickets and muscle
weakness.
• The tumour may be small and difficult to detect.
• But removal of tumour reverses the biochemical
abnormalities and heal the rickets.