Rickets Flashcards
Definition
Metabolic bone disease due to failure of mineralization of osteoid tissue of the growing bones due to either:
y Defective intake or metabolism or function of vitamine D.
y Inappropriate calcium / phosphate ratio (usually due to hypophosphatemia, rarely due to calcium deficiency)
Calcium deficiency with 2 ry hyperparathyroidism→normal or low ca
- Nutritional vitamin D deficiency (Infantile rickets)
- Secondary vitamin D deficiency due to:
o Malabsorption syndromes (Celiac rickets).
o Decreased liver 25-hydroxylase activity in chronic
liver disease
o Increased degradation e.g. with anti epileptic drugs.
- Rickets with chronic renal failure (Renal osteodystrophy)
- Vitamin D dependent rickets type I
- Vitamin D dependent rickets type II
- Calcium deficiency : nutritional , malabsorption or in
premature infant
Phosphate deficiency without 2 ry hyperparathyroidism → normal ca level
- Decreased phosphate intake
y Premature infants (rickets of prematurity)
- Renal phosphate losses e.g.
y Familial hypophosphataemia.
y Fanconi syndromes
y Overproduction of phosphatonin e.g. Tumor-induced
rickets
Vitamin D Deficiency Rickets → Predisposing factors
. - Commoner in winter : - Commonest age p 6 months - 24 month.
: - More in rapidly growing infant e.g. twins & preterm.
- Less in infants with arrested growth e.g. PCM & cretinism.
Vitamin D Deficiency Rickets → etiology
A. Decreased vitamin D intake due to:
- Lack of rich sources of vitamin D e.g. egg yolk, meat, fortified milks, fish liver oil.
- Use of rachitogenic diet with:
- Poor sources of vitamin D as fresh animal milk ,cereals and carbohydrates.
- Poor sources of calcium as cereals ,and excess leafy vegetables
- Inappropriate calcium /phosphate ratio as in fresh animal milk
B. Lack of access of ultra violet rays to the skin due
Clinical picture → Early Rickets
1- Anorexia, irritability, & sweating of forehead
2- Craniotabes
- Skull bones yield under pressure p Ping - pong or egg shell crackling sensation.
- Due to thinning of inner table of the skull
- Disappear by the end of 1 st year.
- Detected by pressing over occipital or parietal bone
3- Rachitic rosaries: palpable enlargement of costochondral junctions (excess osteoid)
Clinical picture → advanced Skeletal Changes
- Head
Large head ,Large anterior fontanel (delayed closure). Asymmetric skull; may be box shaped
Frontal & parietal bones bossing due to excess osteoid
Depressed nasal bridge
Delayed teething, dental caries - Chest
🌺Rachitic rosaries
- Visible & Palpable.
- Rounded, Regular, Non tender
🌼Longitudinal sulcus p lateral to the rosaries
🌻Harrison sulcus p transverse groove along costal insertion of the diaphragm Chest
🌹deformities:
* Pigeon chest p sternum & adjacent cartilages
project forwards.
* Funnel chest p depression of the sternum &
flaring out of the lower ribs.
Other skeletal deformities
- Vertebral column : there may be
a. Kyphosis: in dorsolumbar region
- Smooth.
- Apparent on sitting, disappear by lifting.
- With compensatory lumbar lordosis
b. Scoliosis: lateral curvature of the spine - Extremities
a. Broadening of epiphysis of long bones especially at wrist & ankles.
b. Marfan sign: transverse groove over the medial maleolus due to unequal growth of the two ossific centers.
c. Deformities: Due to weight bearing on the soft bones; * Crawling infants:
- Bowing of forearm.
- Anterolateral curvature of femurs
- Anteroposterior curvat1ure of legs * Walking child:
- Bow legs(Genu varus)
- Knock knees (Genu valgum)
- Overextended knees(Genu recurvatum)
Non Skeletal Manifestations
Manifestations:
1- Delayed motor milestones.
2- Abdominal distension (pot belly abdomen) ; with or without umbilical hernia
3- Ptosis of the liver & the spleen (also due to chest deformities).
4- Constipation p due to intestinal hypotonia.
Complications of rickets
1- Respiratory infections & atelectasis due to:
a- Limited chest expansion.
b- Hypotonia of respiratory muscles → weak cough reflex.
2- Gastroenteritis due to intestinal hypotonia → stasis → 2 ry bacterial overgrowth.
3- Tetany : may occur in rickets with hypocalcaemia
4- Skeletal deformities: - Mild and early managed cases p reversible.
- Advanced and neglected cases p permanent.
5- Disproportionate short stature (Rachitic dwarfism)p due to deformities of spine, pelvis & limbs
6- Iron deficiency anemia is a common association ( Von-Jack anemia = anemia , rickets , lymphadenopathy and splenomegaly)
Investigations → lab
o Serum calcium is normal, but may be low (normal = 9 – 11 mg/dl).
o Serum inorganic phosphrus (Ph.) is low (normal value = 4.5 – 6.5 mg/dl).
o Serum Calcium × Phosphate product is low (less than 30).
o Serum alkaline phosphatase enzyme (Alk. Phos.):
- High
- The most sensitive indicator of rachitic activity; due to osteoblastic activity
- Return to normal after complete healing of rickets.
o Serum Parathyroid hormone (PTH) p high.
o Serum 25 (OH) D 3 p low
o Serum 1.25 (OH) 2 D 3 p low in severe vitamin D deficiency
Radiologic
Active rickets
The lower ends show
y Broadening ; widening of the distal end of the metaphysis
y Cupping or concavity ; metaphysis changes from a convex or flat surface to a more concave surface
y Metaphysis loses its sharp border ( Fraying ) y Wide joint space
The shaft shows y Rarefaction p q bone density y May be green stick fracture. y May be deformities
Prevention
a. Vitamin D supplement usually as daily multivitamin
Dose: - For less than 1 year → 400 IU/day mainly for Breast feeders
- For above 1 year p 600 IU/day
b. Advice for: - Exposure of pregnant mothers and infants to sunlight
- Diet with adequate calcium and phosphorus(formula, milk , dairy products)
- Vitamin D and calcium supplement for pregnant and lactating mothers
Curative treatment
a. Vitamin D3 :
* Oral : 2000 – 5000 IU/day for 4 - 6 weeks * Stoss (Shock) therapy :
- 300.000- 600.000 IU IM or oral for 2-4 doses over 1day
- Indicated if compliance is uncertain
Either strategy should be followed by daily vitamin D intake maintenance
b. Advice parents for:
- Advice about Diet and sunlight as before
- Avoid weight bearing in infants during active rickets.
c. Treat complications:
* Tetany * Deformities: osteotomy and reconstruction if severe and persistent.
After 4- 6 weeks of treatment: Look for criteria of improvement;
- Radiologic : Appearance of zone of provisional calcification is the earliest finding.
- Laboratory : Normalization of alkaline phosphatase indicates complete healing
- Clinical: Improved muscle tone but skeletal manifestations may take a longer time ( Some skeletal signs may persist as large head , severe deformities, pigeon chest) Decision: Reduce vitamin D dose to the normal daily requirement (to avoid toxicity)
Rickets with anti epileptic drugs
🌼Prolonged anti epileptic medicines ( phenytoin , phenobarbitone or carbamazepine ) → enzyme inducers → inactivation of 25 (OH) D3
🌼 Poor sun exposure or poor diet in neurologically disabled +
🌼 Clinical , lab and radiologic features of infantile rickets
Treatment: Oral calcium+ Sun exposure + 25 OH D3
Prevented by extra dose of vit D for all susceptible epileptics
