湘雅儿科精品课件-Rickets of VitD Deficiency

第五章第五节(2)

Rickets of VitD Deficiency

维生素D缺乏性佝偻病

中南大学儿科学教研室刘晓艳

PurposeBe familiar with etiology and pathogenesis of rickits and tetany of Vitamin D deficiency. To master their clinical manifestations, diagnosis ,treatment and prevention . To understand their differential diagnosis.

Definition Rickets

is a very common nutritional deficient disease in young children especially under two years old of age. VitD deficiency cause rickets, a metabolic disorder of calcium and phosphorus with a failure to mineralize osteoid tissue of growing bone resulting in bony deformities.

Originates of VitD食物中摄取麦角固醇(次要) 皮肤中7-脱氢胆固醇(主要) 7- dehydrocholesterol 紫外线照射 ultraviolet plant ergosterol

VitD2内源性VitD3

1,25(OH)2D3的作用促进肾小管对 钙磷的重吸收 促进小肠粘膜 对钙磷的吸收

促进旧骨脱钙，增加 细胞外液钙磷的浓度

Metabolism of VitD

Ingested from food

Human skin contains 7dehydrocholesterol(ultraviolet rairradiation)

Vit D3Liver(25-hydroxylase) 25-(OH) -D3( 25-dihydroxycholecalciferol) kidney (1-hydroxylase)

1,25-(OH) 2-D3 (1, 25-dihydroxycholecalciferol)

Regulation of metabolism of Vit D3

Vit D(-)

Liver25-(OH) D3 Hypo serum P(+) (-) (-)

Hyper serum P

Kidney(-)

PTH(+)

Hypo serum Ca

Hyper serum Ca

1,25- (OH)2 D3

(+)

(+)

(-)

Calcitonin

病因 Etiology 日光照射不足

Lack of sunshine 摄入不足 Underfeeding 生长过快 Rapid growth 疾病影响 Influence of diseases 药物影响 Influence of medicine

预防 Prevention 多晒太阳 补充VitD制剂，预防剂量为 400~800IU/d 提倡母乳喂养，及时添加辅食 积极治疗原发病 孕妇多户外活动，注意营养

Pathogenesis

Vit D deficiencyDisturbance of calcification of osteoid tissue + decalcification of skeleton Diminished absorption of Ca and P from intestine

A fall of serum Ca

Proliferation of osteoid tissue

Compensatory function of parathyroid

Increased

Insufficient

Excretion of urine P increased Rachitic metaphases and soften shaft A fall of serum P

increased decalcification of old bone Serum Ca remain normal or slightly lowered

Ca of old bone can’t be mobilized Serum Ca decreased

Ca P product decreased

Rachitic TetanyPathogenesis

Rickets

临床表现 Clinical manifestations

初期 The early stage 年龄 3 months 症状 神经精神症状 (neuro-psychic symptoms) 体征 枕秃 ( the loss of hair in the occipital position) 生化改变 Ca normal ,P normal or , Ca P , AKP X线 No obvious skeletal changes

枕秃

the loss of hair in the occipital position

Clinical manifestations 激期

The advanced stage 症状和体征 生化改变 Ca ↓, P ↓↓ Ca P <30, AKP ↑ X线

方颅 Square head

漏斗胸 Funnel breast

肋骨串珠 Rachitic ros

ary