- 1. RICKETSBY Dr.HAMDY ABO HAGARASSISTANT PROFESSOR
OFPEDIATRICS
2. Defective mineralization of growing bones,due to vitamine D
deficiency or abnormalmetabolism. 3. Sources: A: Diets such as fats
andoils. B: Vitamin D supplements. C: Ultraviolet sunrays effecton
a precursor in the skin (7-dehydrocholesterol).Types: Vitamin D2 of
plant origin Vitamin D3 of animal originand that naturally formed
inthe skin. 4. Metabolism: After absorption from the gut or
formation inthe skin, vitamin D passes through two stepsof
activation before it becomes ready to act:- In the liver: It is
hydroxylated to 25-hydroxyVit D.- In the kidney: It is furtherly
hydroxylated to1,25 dihydroxy Vit D (the active form). 5.
Actions:In the intestine: It increases absorption of Caand P.In the
kidney: It increases reabsorption of Caand P.In bones: It
stimulates mineralization ofbones. 6. Zone of restingcartilage
(onelayer of cells). Zone ofproliferatingcartilage: regularcolumns
of cellsoriginating fromresting layer). 7. Zone of degeneration
(cellsbecome swollen withglycogen, glycolytic enzymesand alkaline
phosphatase.Calcium is deposited in thematrix. It is
sharplydemarcated in X ray film). Zone of ossification
(bloodvessels invade thedeveloping bone withossification and
remodelingresulting in mature bone). 8. Zone of proliferation
increases andbecomes very vascular causingenlargement of
metaphyseal area andinvades the adjacent zone ofdegeneration. Zone
of degeneration fails to mineralizeand the newly formed tissue
calledosteoid is excessively deposited andbeing soft it gives way
with pressurecausing bulging and deformity ofmetaphyseal area of
long bones (this isresponsible for flaring of the ends of longbones
and rachitic rosary). 9. In the shaft: bone is resorbed and
newosteoid is formed around the shaftfrom the periosteum During
healing of rickets: a new line ofcalcified bone (line of
provisionalcalcification) appears at the end ofzone of degeneration
out standingfrom rarefied osteoid then the areabetween it and the
diaphysis graduallyfills with normal density bone. 10. Active
rickets: They occur early, are pathognomonicand diagnostic, and
help in follow up.Distal ends of long bones appearflared, frayed
and cupped. Distance between the distal end ofradius and metacarpal
bones appearswider than normal (by the area filledwith osteoid).
Diaphysis appears rarefied and mayshow double contour or deformity.
11. Healing rickets:Occurs 2-3 weeks aftersuccessful
treatment.Appearance of the line ofprovisional calcification atthe
end of metaphysis,then the osteoid inbetween this line anddiaphysis
graduallyossifies. 12. Healed rickets:Bone density returns to
normal with slightcupping remains as a stigma of previousrickets.
13. Serum alkaline phosphatase is elevated due toover activity of
osteoblasts during the formation ofexcessive osteoid (normal 5-15
Bodansky units/dl). Serum inorganic phosphorus is decreased
(normal4.5-6.5 mg/dl). Serum calcium is maintained within normal
values(9-11 mg/dl) due to compensatory hyperactivity ofparathyroid
gland. Vitamin D and its metabolites are decreased. 14. Vitamin D
deficiency rickets mostcommonly occurs at the end of the firstyear
and during the second year of life. 15. 1.Craniotabes:Occurs due to
thinning of the innertable of occipital bone under thepressure of
intracranial contents withfailure of mineralization.It can be
elicited by gentle pressure byboth thumbs of the occipital
bone,which produces a dent with cracklingsensation (ping pong ball
like).This can be elicited from 3 to 12months of life. 16. 2.
Rosary:Enlargement ofcostochondral junction ofribs giving
theappearance of beads dueto excessive osteoidformation.3.
Radiological finding ofactive rickets.4. Rise of serum
alkalinephosphatase enzyme. 17. Head: Bossing of skull:
excessiveproliferation of cartilage at occipitaland parietal
eminences makes theskull looks like a box. Enlargement of head
circumference. Delayed closure of anteriorfontanels, which remains
widelyopen. Delayed eruption of primary dentitionwith possible
enamel hypoplasia. 18. Thorax: Rosary beads. Longitudinal sulcus:
appears lateralto the rosaries due to compressionof rib cage by
atmospheric pressureat weakest point. Harrisons sulcus: A
transversesulcus along the lower border of thecostal margin due to
inward tractionof the ribs at sites of diaphragmaticinsertion. 19.
Thorax: Forward protrusion of sternumand adjacent costal cartilage.
Everted costal margin belowHarrisons sulcus. The overall shape of
the chestwall is called pigeon chest,which is nearly triangular
incross section. 20. Abdomen: Liver and spleen become palpabledue
to deformed chest and weakabdominal muscles. The abdomenappears
protruded. Pelvis: Pelvic inlet is narrowed by forwardprotrusion of
sacral promontory, whilepelvic outlet is narrowed by
forwardprojection of the coccyx. This might be very hazardous
infemales during labor in the future. 21. Spinal column:Correctable
kyphosis inthe dorsal region andlordosis in the lumbarregion due to
muscleweakness and laxity ofligaments.Scoliosis 22. Extremities:
Enlargement of metaphyseal regionespecially at wrists and ankles
Marfans sign: transverse groove above themedial and sometimes also
the lateralmaleolus. Deformities of long bones due to
weightbearing. Greenstick fracture. 23. Rachitic dwarfism: due
tospinal and lower limbdeformities.Weak muscles and laxligaments
causing delayedlocomotor milestones. 24. Respiratory: infections or
atelectasis due tochest deformities. GIT: diarrhea or constipation.
Bony deformities or fractures. Anemia: due to chronic infection
ordeficiencies. Tetany: due to hypocalcaemia in late casesafter
exhaustion of parathyroids. 25. Usually good with improvement
afterexposure to sun light in the morning orafternoon or after
administration of VitaminD.Deformities improve with normal
growthbut very slowly.Sometimes, severe skeletal deformitiesrequire
orthopedic correction. 26. Exposure to ultraviolet rays insunshine
(10 to 20 minutes/day). Daily requirements of vitamin D are400-800
i.u /day. For low birth weight infants, andpatients of malnutrition
orhypothyroidism during receivingtheir specific treatment,
1000-1500i.u /day are needed for theaccelerated rate of growth. 27.
Oral Vitamin D in a dose of 1500-5000i.u/day for 6-8 weeks.Shock
therapy: Vit D 600,000 i.u by I.M.injection or orally single
dose.After 2-4 weeks, if no radiologic orlaboratory evidence of
complete healingoccurs, the dose can be repeated. 28. Vitamin D
dependent type: due to defective 1-alpha-hydroxylase in the kidney
or failure ofend organ response to it. Familial hypophophatemic
resistant rickets:affects girls more, there is tubular defect
inphosphate retention resulting in excessiveurinary phosphate
losses. Tubular defects such as Fanconi syndromewith urinary loss
ofphosphate, glucose, amino acids andbicarbonates. 29. Chronic
renal failure.Acquired renal tubular damage, e.g.
drugs.Malabsorption syndromes: such as celiacdisease, cystic
fibrosis of the pancreas,cholestasis.Anticonvulsant therapy causing
increasedmetabolism of Vitamin D. 30. THANK YOU
