Overview/Definition

Definition:
-Rickets is a metabolic bone disease caused by vitamin D deficiency, inadequate calcium or phosphate intake, affecting growing bones in children
-Vitamin D deficiency rickets is the most common form, caused by insufficient vitamin D synthesis or intake.
Epidemiology:
-Rickets affects 60-70% of Indian children with subclinical vitamin D deficiency
-Higher prevalence in Northern India (80%) compared to Southern states (40-50%)
-Peak incidence between 6 months to 2 years of age.
Age Distribution:
-Most common in infants 6-24 months during rapid growth phase
-Adolescent rickets (10-16 years) during pubertal growth spurt
-Congenital rickets in severe maternal vitamin D deficiency cases.
Clinical Significance:
-Leading cause of preventable bone deformities in Indian children
-Associated with increased respiratory infections, delayed tooth eruption, and growth retardation
-High morbidity if untreated during critical growth periods.

Age-Specific Considerations

Newborn:
-Congenital rickets manifests as craniotabes, delayed fontanelle closure, hypocalcemic seizures in first weeks of life
-Maternal vitamin D deficiency is primary risk factor
-Requires immediate high-dose vitamin D supplementation.
Infant:
-Classic presentation with delayed closure of fontanelles, craniotabes, delayed tooth eruption, increased susceptibility to respiratory tract infections
-Growth velocity may be normal initially but slows progressively.
Child:
-Bone deformities become prominent - bowing of legs (genu varum/valgum), pectus carinatum, kyphoscoliosis
-Dental problems, muscle weakness, bone pain
-Height velocity significantly affected.
Adolescent:
-Pubertal rickets presents with bone pain, muscle weakness, delayed puberty, increased fracture risk
-Coxa vara, slipped capital femoral epiphysis complications
-Psychological impact of deformities significant.

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Clinical Presentation

Symptoms:
-Bone pain especially in legs and spine, muscle weakness, delayed motor milestones (sitting, walking), increased irritability, restlessness
-Dental problems including delayed eruption, enamel defects, increased dental caries.
Physical Signs:
-Craniotabes, delayed fontanelle closure, rachitic rosary (enlarged costochondral junctions), Harrison groove, pectus carinatum, widened wrists and ankles
-Bowing deformities of legs (genu varum early, genu valgum later).
Severity Assessment:
-Mild: Normal growth, subtle bone changes on X-ray, biochemical abnormalities only
-Moderate: Growth retardation, clinical deformities, significant biochemical changes
-Severe: Multiple deformities, fractures, tetany, seizures.
Differential Diagnosis:
-Hypophosphatemic rickets (X-linked, autosomal), vitamin D-dependent rickets type 1 and 2, renal osteodystrophy, metaphyseal chondrodysplasia
-Differentiate based on biochemistry, family history, response to vitamin D.

Diagnostic Approach

History Taking:
-Dietary assessment for vitamin D and calcium intake, sunlight exposure history, exclusive breastfeeding without vitamin D supplementation
-Family history of rickets, consanguinity
-Maternal vitamin D status during pregnancy.
Investigations:
-25-hydroxyvitamin D level (gold standard), serum calcium, phosphate, alkaline phosphatase, PTH levels
-X-rays of wrists and knees for metaphyseal changes
-Chest X-ray for rachitic rosary
-Complete blood count, renal function tests.
Normal Values:
-25(OH)D levels: Sufficient >30 ng/mL (75 nmol/L), Insufficient 20-29 ng/mL (50-74 nmol/L), Deficient <20 ng/mL (<50 nmol/L)
-Severe deficiency <10 ng/mL (<25 nmol/L)
-Alkaline phosphatase elevated 2-10 times normal.
Interpretation:
-Low 25(OH)D with elevated PTH and alkaline phosphatase confirms vitamin D deficiency rickets
-Low calcium and phosphate in active disease
-X-ray shows delayed ossification, metaphyseal widening, cupping, fraying, pseudofractures.

Management/Treatment

Acute Management:
-High-dose vitamin D3 supplementation: 60,000 IU weekly for 6 weeks for children >1 year
-For infants: 2000-4000 IU daily for 6 weeks
-Calcium supplementation 500-1000 mg daily
-Monitor serum calcium weekly initially.
Chronic Management:
-Maintenance vitamin D3: 400-1000 IU daily based on age and risk factors
-Adequate calcium intake through diet or supplements
-Regular monitoring of 25(OH)D levels every 3 months initially, then every 6 months.
Lifestyle Modifications:
-Adequate sunlight exposure 15-30 minutes daily between 10 AM-3 PM
-Dietary counseling for vitamin D rich foods (egg yolk, fish, fortified foods)
-Breastfeeding mothers should receive vitamin D supplementation.
Follow Up:
-Clinical assessment every 2 weeks initially for symptom improvement and complications
-X-rays at 3 and 6 months to monitor healing
-Growth monitoring monthly
-Biochemical monitoring at 6 weeks, 3 months, then 6-monthly.

Age-Specific Dosing

Medications:
-Vitamin D3 (cholecalciferol) preferred over D2
-Treatment doses: Infants <1 year: 2000-4000 IU daily
-Children 1-18 years: 60,000 IU weekly for 6 weeks OR 4000-6000 IU daily
-Severe deficiency may require higher doses.
Formulations:
-Oral drops for infants (400 IU/drop), sachets (60,000 IU), tablets (1000 IU, 2000 IU)
-Injectable forms available for severe malabsorption
-Calcium carbonate 500-1000 mg daily in divided doses with meals.
Safety Considerations:
-Monitor for vitamin D toxicity - hypercalcemia, hypercalciuria, nephrocalcinosis
-Avoid doses >10,000 IU daily unless severe deficiency
-Check calcium levels weekly during high-dose treatment
-Contraindicated in hypercalcemia.
Monitoring:
-Serum 25(OH)D target levels 30-60 ng/mL (75-150 nmol/L)
-Monitor calcium, phosphate, PTH, alkaline phosphatase
-Urinalysis for proteinuria, hematuria
-Renal ultrasound if nephrocalcinosis suspected.

Prevention & Follow-up

Prevention Strategies:
-Universal vitamin D supplementation for all infants 400 IU daily from birth
-High-risk groups (dark skin, limited sun exposure, exclusive breastfeeding) need higher doses
-Pregnant women should receive 2000 IU daily.
Vaccination Considerations:
-No specific vaccine interactions
-Ensure age-appropriate immunizations are up to date
-Vitamin D deficiency may impair immune response, making vaccination more important for preventing infections.
Follow Up Schedule:
-Initial follow-up at 2, 4, 6 weeks for symptom improvement and biochemical normalization
-Then 3, 6, 12 months for bone healing assessment
-Annual screening for high-risk children
-Growth monitoring every 3 months.
Monitoring Parameters:
-Clinical: Growth velocity, bone deformity progression, dental health, muscle strength
-Laboratory: 25(OH)D levels every 6 months, annual assessment of calcium, phosphate, PTH, alkaline phosphatase
-Radiological: Annual X-rays until healing complete.

Complications

Acute Complications:
-Hypocalcemic seizures, tetany, laryngospasm in severe deficiency
-Increased susceptibility to respiratory tract infections
-Dilated cardiomyopathy in severe cases
-Delayed wound healing and increased bleeding tendency.
Chronic Complications:
-Permanent bone deformities (genu varum/valgum, pectus carinatum, kyphoscoliosis), short stature, dental problems (delayed eruption, caries, enamel defects)
-Pelvic deformities affecting future childbirth in girls.
Warning Signs:
-Worsening bone pain, new onset seizures, muscle cramps, increased frequency of infections, failure to improve with treatment, progressive deformities despite adequate treatment
-Symptoms of vitamin D toxicity during treatment.
Emergency Referral:
-Hypocalcemic seizures requiring IV calcium gluconate, respiratory distress, signs of heart failure, severe deformities requiring orthopedic intervention
-Non-response to standard treatment suggesting vitamin D-dependent rickets.

Parent Education Points

Counseling Points:
-Rickets is completely preventable and treatable with vitamin D supplementation
-Early treatment prevents permanent deformities
-Compliance with treatment is crucial for bone healing
-Dietary sources alone are often insufficient in Indian context.
Home Care:
-Ensure daily vitamin D supplementation as prescribed
-Encourage safe sun exposure during recommended hours
-Provide calcium-rich foods (milk, yogurt, cheese, green leafy vegetables)
-Monitor child for improvement in symptoms and activity levels.
Medication Administration:
-Give vitamin D supplements with meals for better absorption
-Weekly high-dose can be given on fixed day to ensure compliance
-Mix liquid preparations with food if child refuses direct administration
-Store supplements in cool, dry place.
When To Seek Help:
-Immediate medical attention for seizures, muscle cramps, difficulty breathing, or signs of severe illness
-Routine follow-up if no improvement in bone pain or activity level after 4-6 weeks of treatment
-New onset bone deformities during treatment.