May 30, 2024

Rickets is the disease of infancy and childhood due to insufficiency of calcium and is clinically characterized by softened and deformed bone

Rickets

Synthesis of Vitamin D

Synthesis of Vitamin D

Etiology

  1. Vitamin D disorders
  2. Calcium deficiency
  3. Phosphorus deficiency
  4. Renal loss
  5. Distal Renal tubular acidosis

Vitamin D disorders

  • Nutritional Vitamin D deficiency
  • Congenital Vitamin D deficiency
  • Secondary Vitamin D deficiency
    • Malabsorption
    • Increase degradation
    • Decrease liver 25-hydroxylase
  • Vitamin D-dependent rickets Type I
  • Vitamin D-dependent rickets type II
  • Chronic Renal failure

Calcium deficiency

  • Low intake (Diet, Premature infants)
  • Malabsorption

Phosphorus deficiency

  • Intake of aluminum-containing antacids

Renal Loss

  • X linked Hypophosphatemia rickets
  • Autosomal dominant Hypophosphatemia rickets
  • Hereditary hypophosphatemia rickets with hypercalcemia

Overproduction of phosphatonin

  • Tumor-induced rickets
  • McCune Albright Syndrome
  • Epidermal nevus syndrome
  • Neurofibromatosis

Fanconi Syndrome

Dent disease

Pathology of rickets

Histologically, features are seen in osteoid (protein base with/without calcification)

2 Stages:

Active Stage

  • The orderly progression of endochondral ossification: Interrupted
  • The proliferation of cartilage cells, palisade arrangement, and formation of matrix proceed normally but matrix calcification is the deficit
  • Cartilage (noncalcified) column proliferate meanwhile 10-20 times the normal depth of cells ( haphazardly)
  • This leads to an enormous accumulation of proliferated cartilage and osteoid tissue resulting in widened, irregular line (epiphyseal), of radiolucency extending deeply into the metaphysis
  • Osteoids laid down in both meta-diaphysis, often develops subperiosteally as exuberant growth near the epiphyseal plane ( Rachitic rosary, enlargement of costochondral junction)
  • Marrow display: Moderate degree of vascularity and fibrosis

Healing Stages

  • Calcium salt deposits in the zone of preparative calcification
  • Capillary penetrate the column of proliferative chondrocytes and lay calcified cartilage osteoid
  • Osteoid: calcified and transfer to bone
  • Osteoid trabeculae atend normal shape
  • Fibrotic marrow replaced by fat

Clinical Pictures

Clinical features of rickets
Clinical features of rickets

Growth restriction

Poor muscle tone

Incomplete fractures

Radiological findings in Rickets

Fraying: Edge of metaphysics loses its sharp border

Cupping: The edge of metaphysis changes from convex to flat or concave shape

Widening distal end of metaphysis

Thickened growth plate

Diaphysis: coarse trabeculae

Generalized rarefaction

Long weight-bearing bone: Bends and thickening on the concave side

In healed phase

A dense line appears at the epiphyseometaphyseal junction: newly calcified cartilages

Epiphyseal lines become narrow and well developed

Frankel line: Sign of healing

The epiphyseal ossified nucleus becomes more dense, large, and well defined

Bending deformity disappears

Lab features of rickets

Lab in Rickets
Copied from Apurv Mehra’s Orthopedics quick Review

Treatment Options

Prophylaxis

Administration of Vitamin D

Exposure to sunlight

Especially for premature infants and those an artificial milk feeding

Recommended dietary allowance (RDA)

Calcium

700 mg for children

1000-1200 mg for 50-70 years old females/ all above 70 years

Vitamin D

800 IU for children and elderly

600 IU for all others

Treatment of nutritional rickets

  1. Stoss therapy: 300000-600000 IU given over 1-5 days
  2. Alternatively, 2000-6000 IU/ day for 8-12 weeks

Either strategy is followed by a maintenance dose of 400-1000 IU in infants, 600-1000 IU in older children

Given with multivitamins

Supplementary, calcium to all children with 50-70 mg/ day for 6 -12 weeks

Monitoring treatment

  • Serum ALP starts normalizing after 3-6 months
  • Radiological healing (visible as calcification) 2-4 weeks after
  • If an overdose of Vitamin D results in hypercalcemia with urinary calcium deposits

Deformities in the lower leg spontaneously regress, but it fails to regress then osteotomy

Vitamin D Resistance Rickets

  1. Familial hypophosphatemia rickets
  2. Renal tubular acidosis
  3. Vitamin D-dependent rickets
Vitamin D Resistant RicketsVitamin D deficient rickets
EtiologyInheritedAcquired
Muscular weaknessAbsentPresent
Hypocalcemic tetanyAbsentPresent
Serum PhosphorusAlways low but after treatment never returns to normal but risesLow/ Normal, if low after treatment returns to normal
Growth rateSeldom becomes normal, the patient remains DwarfNormal growth rate resumes

Vitamin D-dependent Rickets

Vitamin D-dependent Rickets

Renal Osteodystrophy

Renal osteodystrophy is defined as alternation in bone morphology associated with CKD based upon bone biopsy

It is not a single pathology entity

Reflects the disorder pathophysiological status associated with advanced renal disorder

Causes of Renal Osteodystrophy

Renal Osteodystrophy

Failure to synthesize 1,25 dihydroxy Vit D3

25-OH Vit D2–> 1 α hydroxylase/ PCT –>1,25-(OH)2 Vit D3 (Calcitriol)

Vitamin D synthesis

Decrease of Vit D3 => Failure of Intestinal Ca++ absorption=> No bone mineralization =>Osteomalacia

Osteomalacia

Pathology: the thickened layer of an unmineralized matrix (osteoid)

Leaches Calcium from bone

  • Subperiosteal bone resorption
  • Bowing of digits

Failure to excrete PO4

Hyperphosphatemia

Binds to serum Ca++

Decrease availability to ionized free Ca ++ level

Parathyroid gland

Decrease serum Ca++ in blood

Calcium sensing receptor in PTH

↑ in PTH

Absorbs and leaches calcium from the bone

Osteitis fibrosa cystica

  • Holes come from activated osteoclast
  • it causes microfracture, bleeding, and granulation of tissue
  • Looks brown so-called BROWN TUMOR

Management of Renal Osteodystrophy

Treatment of Renal Osteodystrophy

Radiological Features of Scurvy

Radiological features of scurvy

Trummerfield zone: Lucent metaphyseal band
Frankel’s line: Dense zone of provisional calcification
Pelkin’s spur: Metaphyseal spur that results in a cupping of metaphysis
Pelkin’s fracture: Metaphyseal corner fracture
Cortical thinning: Pencil point cortex
Periosteal reaction: Due to subperiosteal hemorrhages
Wimberger’s ring sign: circular opaque radiological shadow surrounding the epiphyseal center of ossification due to bleeding

See also: Osteogenesis Imperfecta

See also: Osteopetrosis