Edition 43 - 2013, May / Images

Images in Pediatric Endocrinology: VITAMIN D DEFICIENT RICKETS – Ed. 43

Riu Carmen, Tau Cristina, y Di Palma M. Isabel

Servicio de Endocrinología Hospital de Pediatría “Prof. Dr. J.P.  Garrahan”, Buenos Aires, Argentina

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Image 1: X-rays before therapy (2.8-y-old): Moderate osteopenia, Distal femur and proximal tibia metaphysis widening, rickets in metaphysis (metaphysis effacement).

Clinical Case:

A 2.8-year-old boy, born in Tierra del Fuego, was referred to the Garrahan Hospital for multidisciplinary evaluation in order to rule out a presumptive genetic syndrome. Family history was unremarkable. The child had genu varum since 14 months of age and he had difficulty walking. He fell several times and fractured his clavicle in one occasion. Additionally, he complained from pain while walking.  On admission, physical examination showed: adecuateheight and weight, normal body proportions, normal bone maturation, enamel hypoplasia, rachitic rosary along the costochondral junctions, prominent belly, bilateral genu varum, wide wrists, and irritability. X-rays revealed moderate osteopenia, bilateral tibia bowing, widening of the distal femur and proximal tibia metaphyses with an associated increase in the thickness of the radius and ulna epiphyses. Laboratory tests showed:im43T1iThese findings are consistent with RICKETS SECONDARY TO VITAMIN D DEFICIENCY. Treatment was started with 300,000 IU of vitamin D3 during a month plus dairy food intake of around 750-1000 grs. After one month of treatment, PTH and alkaline phosphatase were normalized.

Subsequent maintenance treatment consisted of 400 IU/day vitamin D3. After 6 months of treatment the child had improved clinically as well as radiologically.  He had become less irritable and had much less pain.  The X-rays showed bone healing with extensive periostal new bone formation and ossification of the distal epiphyses.

At present, the boy is still on maintenance treatment with vitamin D3 and increased dairy food intake.im43T2i

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Image 2: Lower limb X-rays after 6 months of treatment (3.3 years old): Healing of active rickets. Signs of new periostial bone formation, increased ossification.

COMMENTS

RICKETS SECONDARY TO VITAMIN D DEFICIENCY:

Humans have two sources of vitamin D. The first and most important one is ENDOGENOUS, produced by the synthesis of vitamin D3 or cholecalciferol in the skin from solar UV rays. The second is the intake of vitamin D-rich food, containing vitamin D 2 or ergocholecalciferol. Both metabolites must become active in the liver and kidneys, transforming into 1,25 (OH)2 vitamin D. Thus, factors that diminish exposure to UV rays (like in this case, lack of sunlight as our patient comes from the southern region of Argentina), or extremely restricted diets, put humans at risk of vitamin D deficiency.

Pathophysiology:imT432biSigns and symptoms:

The most important sign of rickets is alteration of bone mineralization. Rickets mainly affects the long bones which grow actively throughout childhood.  The specific manifestations of disrupted endochondral ossification and mineralization at the physes become apparent with accumulation of excessive disorganized hypertrophic cartilage and widened metaphyses, clinically appearing as knobby knees. Similar expansion of the metaphyses at the costochondral junctions produces the so-called rachitic rosary. Bowing of long bones, particularly anterior and lateral bowing of femurs and tibias, might arise from the excessive cartilage in the metaphyses.  Other sings are: enamel hypoplasia, prominent belly, irritability, and pain when walking. Signs of hypocalcemia may be found as well.

X-rays:

Diagnostic radiographic features of rickets are those that reflect the disorder of mineralization and ossification affecting the growth plate. These findings are best seen in the metaphyses of the fastest growing bones including the distal radius (resulting in the so-called “champagne-cup” image), distal ulna and femur, proximal and distal tibia, and the anterior ends of the middle ribs. The presence of bone x-ray alterations are a sign of advanced disease. X-rays also reveal osteopenia, bilateral tibia bowing, widening of the distal radius, ulna, femur and proximal tibia metaphyses with an associated increase in the thickness of the epiphyses.im43T3iFrom the phospho-calcium metabolism data found in the Clinical Case herein presented, our patient should be classified as being at Stage II of Vitamin D deficient rickets.

Treatment:

Rickets treatment is with supplementation of high doses of vitamin D, which differ depending on the children age and must always be accompanied with increase dairy food intake. Sometimes calcium supplements are needed.  In case of hypocalcemia, this one should be treated first. After rickets acute treatment, maintenance treatment should follow, with a dose of vitamin D adequate for each child.

Follow-up:

During follow-up, serum calcium, phosphate, and urine calcium should be measured after one month treatment. Later on, every 3 months, calcium, phosphate and vitamin D measures are needed, as well as long-bone x-rays after 6 month treatment. Vitamin D measurements are needed annually.im43T4iProphylaxis:

It must be taken into account that the principal source of vitamin D for humans is endogenous (synthesis of vitamin D 3 in the skin) and, although currently food supplementation with vitamin D is required by law, it is still insufficient for human requirements.

Recommendations:

  1. In breastfeeding babies, supplementation with between 100 – 400 IU of vitamin D per day is required.
  2. In preterms, the Pediatric American Academy recommends 400 IU of vitamin D per day.
  3. Children as well as adults who live at latitudes below 42 degrees south of the equator should be supplemented with 100,000 IU of vitamin D throughout autumn in order to prevent vitamin D deficiency in winter.
  4. Children, as well as adults, who live in regions South of parallel 42 in the Southern hemisphere and North of the same parallel in the Northern hemisphere should receive vitamin D supplementation (100000 IU) in a single dose or fractionated daily during autumn to avoid vitamin D deficiency during winter.

im43T51References:

  1. Shore RM y Chesney RW.  RICKETS: part II Pediatric Radiology  2013,  43:152-172
  2. Pombo M y cols. Tratado de Endocrinologia Pediatrica, 4ta edición 2009.
  3.  Misra, M. Kappy, M. y col. Vitamin D deficiency in children and its management: Review of current knowledge and recommendations Pediatrics, 2008 122:398-417
  4. Wagner, C., Greer FR. Prevention of rickets and vitamin D: deficiency in infants, children and adolescents, Pediatrics, 2008 122:1142-52
  5. Holick, M. Resurrection of vitamin D deficiency and rickets”, The Journal of Clinical Investigation, 2006 116:2062-72

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