Rickets

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    • Rickets and osteomalacia
      • Both occur due to Vitamin D deficiency
      • organic matrix of the bone fails to calcify properly, leaving large osteoid seams.(MCQ)
      • Rickets occurs in the growing bones of children
      • osteomalacia in the bones of adults
    • Rickets
      • characterised by failure of normal mineralisation
      • seen prominently at the growth plates
      • resultingin softening of the bones and development ofdeformities. (MCQ)
      • Causes
        • Two types of rickets i.e., Type I and Type II
        • Type I(MCQ)
          • a deficiency of vitamin D
          • a defect in its vitamin D  metabolism.
        • Type II (MCQ)
          • deficiency of phosphates in the extra-cellular fluid because of
          • defectivetubular resorption
          • diminished phosphate intake.
        • Nutritional deficiencycommonestcause of rickets(MCQ)
      • Clinical features
        • Nutritional rickets occurs in children about 1 year old(MCQ)
        • It may occur in older children with malabsorption syndrome
        • Craniotabes(MCQ)
          • manifestation of ricketsseen in young infants.
          • Pressure over the softmembranous bones of the skull gives the feeling
          • of a ping pong ball being compressed andreleased.
        • Bossing of the skull: (MCQ)
          • Bossing of the frontal andparietal bones becomes evident after the ageof 6 months. (MCQ)
        • Broadening of the ends of long bones(MCQ)
          • Seen nostprominently around wrists and knees
          • Seenaround 6-9 months of age. (MCQ)
        • Delayed teeth eruption is noticed in infants. (MCQ)
        • Harrison’s sulcus: (MCQ)
          • A horizontal depression,along the  lower   part ofthe chest,corresponding to the insertion of diaphragm.
        • Pigeon chest: The sternum is prominent. (MCQ)
        • Rachitic rosary: (MCQ)
          • The costo-chondral junctionson the anterior chest wall become prominent,
          • giving rise to appearance of a rosary.
        • Muscular hypotonia: (MCQ)
          • The child’s abdomenbecomes protruberant (pot belly) because ofmarked muscular hypotonia.
          • Visceroptosis andlumbar lordosis occurs.
        • Deformities:
        • knock knees or bow legs is acommon presentation of rickets, once the childstarts walking.
      • Radiological features
        • Early radiological changes are observed in thelower ends of the radius and ulna. (MCQ)
        • X-rays of bothwrists and kneesantero-posterior views are usedfor screening a patient suspected of rickets.
        • Following radiological signs may be seen (MCQ)
          • Delayed appearance of epiphyses. (MCQ)
          • Widening of the epiphyseal plates: (MCQ)
            • Normal widthof the epiphyseal plate is 2-4 mm.(MCQ)
            • In rickets itis increased because of excessive accumulationof uncalcified osteoid at the growth plate.
          • Cupping of the metaphysis:
            • Zone of provisional calcification(MCQ)
              • Normally, themetaphysis meets the epiphyseal plate as asmooth line of sclerosis
              • In rachitic bones, this line isabsent and the metaphyseal end appearsirregular.
            • The cartilage cells accumulating at the growth plate create a depression in the soft metaphyseal end, giving rise to a cup shaped appearance(MCQ)
          • Splaying of the metaphysis: (MCQ)
            • The end of themetaphysis is splayed because of the pressureby the cartilage cells accumulating at thegrowth plate.
          • Rarefaction of the diaphysial cortex occurs late. (MCQ)
          • Bone deformities: (MCQ)
            • Knock knees, bow legs andcoxavara are common deformities in olderchildren.
      • Biochemical investigations in Rickets(MCQ)
        • Serum calcium is usually normal or low
        • serum phosphate is low
        • serumalkaline phosphatase is high.
      • Treatment
        • Medical treatment:
          • Administration of vitamin D 6,00,000 units as a single oral dose induces rapid healing. (MCQ)
          • If the line of healing (a line of sclerosis on the metaphyseal side of the growth plate) is not seen on X-rays within 3-4 weeks of therapy, same dose may be repeated. (MCQ)
          • In cases where the child responds to vitamin D therapy, a maintenance dose of 4001.U. of vitamin D is given per day. (MCQ)
          • If there is no response even after the second dose, a diagnosis of refractory ricketsis made. (MCQ)
        • Orthopaedic treatment;
          • Conservative methods:
            • Mermaid splints – specially designed splints(MCQ)
            • Orthopaedic shoes for correction of knee deformities.
          • Operative methods:
            • Moderate or severe deformities often require surgery.
            • This can be performed any time after 6 months of starting the medical treatment.
            • Corrective osteotomies, depending upon the nature of deformities, are performed.
    • Osteomalacia
      • Osteomalacia meanssoftening of bones
      • Causes
        • common in women who live in ‘purdah,’ and lack exposure to sunlight
        • dietarydeficiencyof vitamin D
        • under-nutrition during pregnancy(MCQ)
        • mal-absorption syndrome, after partial gastrectomy(MCQ)
      • Clinical features
        • Bone pains
        • Muscular weakness
          • have difficulty in climbing upand down the stairs.
        • A waddling gait is notunusual.
        • Tetany may manifest as carpopedalspasmand facial twitching.
        • Spontaneous fractures occur usually in spine,and may result in kyphosis.
      • Investigations
        • Radiological  examination:
          • Plain  X-raysappear to be of ‘poor quality’ i.e., not sharpand well-defined. Following findings may be present
          • Diffuse rarefaction of bones.
          • Looser’s zone (pseudo-fractures): (MCQ)
            • These areradiolucent zones occurring at sites of stress.
            • Common sitesare the (MCQ)
              • pubicrami, axillary border of scapula, ribs
              • medial cortexof the neck of the femur.
            • These are causedby rapid resorptionand slow mineralisationand may be surrounded by a collar of callus.
          • Triradiatepelvis in females.(MCQ)
          • Protrusio-acetabulii.e., the acetabulumprotruding into the pelvis.(MCQ)
        • Bone biopsy:
          • A bone biopsy from the iliaccrest usually confirms the diagnosis.
          • Thecharacteristic histological finding is excessiveuncalcified osteoid.(MCQ)
        • Serum: (MCQ)
          • The serum calcium level is low
          • phosphates    are    low
          • alkalinephosphatase high.
      • Treatment
        • Vitamin D in daily maintenance doses of 400 I.U.is sufficient.
        • In patients with renal disease,alfa-calcidol (an activated form of vitamin D) may be used.
        • Calcium supplementation should also be given.
    • Hyperparathyroidism
      • Clinical bone diseaseoccurs in less than half of the patients with hyperparathyroidism.
      • For reasons unknown, hyperparathyroidism tends to present either withbone disease or with renal stones, but not both.
      • Parathyroid hormone and bone:
        • PTH acts directly on the bone to release calcium   into   the   extra-cellular   fluid
        • It stimulatesosteoclasticresorption.(MCQ)
        • It activates the adenylcyclase so that the formation of cyclic AMP is increased, which in turn increases the synthesis of specific lysosomal enzymes.
        • These enzymes break down the organic matrix of bone and release calcium.
      • Clinical features
        • more common in women.
        • third to fifth decades of life
        • Bone pains: (MCQ)
          • most common initialfeature.
          • There is tenderness on palpating thebones, especially in the lower limbs and back.
          • Pain  is  usually  associated  with   generalweakness, pallor and hypotonia.
        • Pathological fracture:(MCQ)
          • Common sites of fractures are dorso-lumbarspine, neck of the femur and pubic rami.
        • Brown’s tumour:(MCQ)
          • This is an expansile bonelesion, a collection of osteoclasts.
          • It commonlyaffects the maxilla or mandible, though anybone may be affected.
          • Anorexia, nausea, vomiting and abdominal crampsare common presenting complaints.
          • Occasionally, renal colicswith haematuria,because of renal calculus, may occur.
      • Radiological investigations
          • X-ray examination consists of the
            • lateral view of the skull
            • dorso-lumbar spine (AP/lateral views)
            • both hands (AP view),
            • pelvis(AP view)
            • X-ray of the region with symptoms
          • Radiologic signs
            • Irregular, diffuse rarefaction of the bones.
            • Salt pepper appearance: (MCQ)
              • The skull bones show awell-marked stippling, but the opaque areasare small pin head size.
            • Loss of lamina dura: (MCQ)
              • What is  laminadura.
                • A tooth socket is made upof thin cortical bone seen as a white linesurrounding the teeth.
              • laminadura.gets absorbed in hyper-parathyroidism.
            • Sub-periosteal resorptionof the phalanges (MCQ)
              • A diagnostic feature of hyperparathyroidism(generalised variety).
              • Resorption may alsooccur at lateral end of the clavicle.
            • Spine shows central collapse of the vertebralbody and biconvex discs.(MCQ)
            • Pelvis and other bones show coarse striationswith clear cyst-like spaces.
            • Brown’s tumour(MCQ)
              • anexpansile lytic lesion,which appears like a bone tumour
              • generally affect the maxilla/mandible.
              • Extra-osseous radiological features such asrenal calculi etc. may be present.
          • Lab
            • Serum (MCQ)
              • calcium is high
              • phosphateslow
              • alkaline phosphatase high.
            • Urinary excretion(as found on 24 hour urine analysis.) of (MCQ)
            • calcium is low
            • phosphates high