lack of vitamin D, calcium, orphosphate, which leads to softening and weakening of the bones. Defective mineralization of bone matrix –excessive unmineralised osteoid
Vitamin D helps the body properly controlcalcium and phosphate levels in the body.When the body is deficient in vitamin D, it isunable to properly control calcium andphosphate levels calcium and phosphorous are found in milk andgreen vegetables.
Defective Vitamin D metabolism – lowering of calcitriol - intestinal malabsorption of calcium - reduction of serum calcium – Parathyroid stimulation – normalised S.calcium at the expense ofreduced S.Phosphate
ultraviolet rays 7-DihydrocholesterolCholecalciferol (Vitamin D3)- in dermisVit D2 absorbed thru small intestineTransport in serum- binds with X-globulin25-Hydroxylation in Liver1,25- Dihyroxylation in Kidney – active form
Decrease in effect & amount of Sunlight Bread/Chapathi rich in Phytate bind dietarycalcium – reduced absorption Infants who are exclusively breastfed maydevelop vitamin D deficiency. Poor Dietary intake of Ca & Vit D Malabsorption disorders – Coeliac d/s, hepaticosteodystrophy, lactose intolerance
Renal – Renal osteodystrophy, Nephrectomy,renal failure, hypoparathyroidism,X-linked hypophosphatemia/Vit D resistantricketsVitamin dependant Type I (Inability to hydroxylate)Vitamin dependant Type II (Receptor insensitivity) Anticonvulsant therapy( 25OH in liver)
Failure of deposition of Ca along maturecartilage cell columns Disorderly invasion of cartilage by bloodvessels Lack of reabsorption at the zone ofprovisional calcification Increased thickness of epiphyseal plate
Abundant osteoid with Defective mineralization No resorption of uncalcified osteoid byosteoclasts Normal osteoblast – laid irregularly Abnormal arrangement of collagen bundles incompact bone
Long bones bent when child startscrawling/walking
Bone pain or tendernessArms Legs Spine Pelvis Skeletal deformitieso Bowlegso pigeon chesto rachitic rosaryo Frontal bossingo Spine deformities (spine curvesabnormally, including scoliosis orkyphosis )o Pelvic deformities
Increased tendency toward bonefractures Dental deformitieso Delayed formation of teetho Defects in the structure of teeth, holes inthe enamelo Increased incidence of cavities in theteeth ( dental caries )o Decreased muscle tone (loss of musclestrength) Muscle cramps Impaired growth Short stature
Dense shadow Dense line at the end of metaphysis-deposition of Ca Stage of repair
Increase in breadth of metaphysis Clearly defined bone Normal content of Ca salts Bone completely repaired
Serum Ca low or normal.o Tetany -prolonged muscle spasm.o Chvosteks sign may be positive (a spasm offacial muscles occurs when the facial nerveis tapped) S.Phosphorus may be low. S.ALP may be high. ABG may reveal metabolic acidosis Urinary Ca may be low .
24-hydroxylase assay – for vitamin Ddependency rickets Serum 25-OH vitamin levels A bone biopsy is rarely performed but willconfirm rickets.
Goals - relieve symptoms andcorrect the cause of the condition. Underlying cause must be treated to preventrecurrence.
Medical treatment Prevention of deformity Treatment of existing deformity
Dietary sources of vitamin D include fish, liver,milk and cheese. Exposure to moderate amounts of sunlight isencouraged. Reduce cereal containing phytates Supplemention of Calcium andVitamin D – 3000 i.u./day
Before treatment and 2 years after treatment with calcium
Control of movements – reduced pressure uponlimbs (soft bones easily bent by pressure / musclestrain) Positioning or bracing with ‘rickets’ splints may beused.
Correction by splinting In young children below 4 yrs Useful in lower limbs Continuous supervision needed to preventsores
Correction by osteotomy When deformity is near a joint At least stage 3 in radiograph
Chronic skeletal pain Skeletal deformities Skeletal fractures, may occur without cause
Rickets of prematurity Very premature infants at risk Risk factors- hepatobiliary d/s, TPN, Diuretic therapy, chest percussion therapy Pathologic # in NICU Readily heal with treatment
Antiepileptic medications Induce microsomal P-450 enz Decreased Vit D Should be suspected in neurologic patientshaving seizures Start having frequent #
Familial hypophosphatemic rickets X-linked dominant (MC)- Mutn in PEX gene Aut dominant 12p13 – phosphatonins – fgf23 – cause phosphaturia Aut recessive
Renal tubule unable to retain PO4 End organ insensitivity to vit D (AR) Kidney unable to perform 2nd hydroxylation Renal tubular acidosis (kidney excretes fixedbase and wastes bicarbonate) Ca ppt – renal calcinosis
Surgery not efficacious – multilevel osteotomyto correct mechanical axis Recurrent deformity common Surgery when - gait compromised/severepain
Oncogenic hypophosphatemicosteomalacia Asso with Neurofibromatosis, fibrousdysplasia Osteoblastoma, hemangiopericytoma ofbone, skin tumors (disrupts renal tubular abs of po4) Secrete phosphatonins Resolve with excision of tumor
C/C pyelonephritis Congenital Abnormalities Polycystic kidney d/s Secondary hyperparathyroidism Leads to actvn of osteoclast and resorption ofbone (high turn over d/s)
Glomerulus unable to excrete Phosphorus Vit D prodn reduced Ca abs from S.Intestine reduced PTH triggered Increased S.Ca – bone demineralization Precipitate in cornea, skin, blood vessels
C/F similar to Nutritional. Angular deformity, SCFE, AVN Radiography – cuppping of physis notpresent Subperiosteal resorption in phalanges, MCand ulna (feature of Hyperparathyroidism) Osteosclerosis of skull, rugger jersey spine Lytic areas in long bones (Brown tumors) Treat underlying d/s- Ca, Vit D, growthhormone, osteotomy, Ilizarov
Ca Normal or low in all Phosphate is reduced in all except RenalOsteodystrophy ALP and PTH high in all 25 OH Vit D N or high in all exceptnutritional (decreased) 1,25 (OH)2 N or low in all except Vit Ddependent typeII (receptor insensitivity)
Maintain an adequate intake of calcium,phosphorus, and vitamin D. This may require dietary supplements inpeople who have gastrointestinal or otherdisorders Renal causes of vitamin D should be treatedpromptly.
Levels of calcium and phosphorus should bemonitored regularly in people who have renaldisorders . Genetic counseling may help people with a familyhistory of inherited disorders that can causerickets.
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