RICKETS Generalized metabolic disorder, characterized by a failure of calcification of the cartilaginous growth plate in growing organisms, whose epiphyses have not yet fused.

Rickets – Historical Perspective 19th CENTURY - Rickets rampant among the poor children living in the industrialised & polluted northern cities “Disappearance of Rickets” in early 20th Century: Cod-liver oil supplements in 1930s Improvement in nutrition Pollution control measures Recent resurgence of Rickets Francis Glisson - "De Rachitide” 1650

Basic Vitamin D Chemistry Vitamin D2 or Vitamin D3 are incorporated in chylomicrons and absorbed into the lymphatic system Then become bound by vitamin D binding proteins (DBP) and lipoproteins. Taken to liver and hydroxylation occurs and forms 25-hydroxyvitamin D (the major from of ‘D’ measured to determine a person’s vitamin D status).

Basic Vitamin D Chemistry 25(OH)D is bound by DBP, the complex is transported via circulation to renal tubule cell surface, then is transported into the cell. Moves to mitochondria where it is converted to 1,25-dihydroxvitamin D…the form responsible for calcium and phosphorus homeostasis.

Vitamin D Activity

Importance of Vitamin D

Functions of chemicals involved in bone formation Alkaline phosphatase (isoenzyme is elevated in conditions such as rickets that are associated with high bone turnover) Calcitonin (bone; intestine; kidney) Calcitriol (bone: indirectly; intestine; autoregulation of calcitriol production by the kidney; parathyroid gland) Parathyroid hormone (bone: intestine: indirectly; kidney - calcitriol, calcium and phosphorus )

Types of Rickets Vitamin D Deficient Rickets(nutritional) Vitamin D Dependent rickets Vitamin D Resistant Rickets Renal Rickets Hepatic Rickets Congenital Rickets

Rickets Definition: Vitamin: an organic chemical that cannot be synthesized by humans but need to be ingested in the diet to prevent disorders of metabolism. Vitamin D Deficiency: commonly referred to as ‘Rickets’ when it occurs in children…and osteomalacia in adults. Decreased intestinal absorption of calcium and phosphorus….persistent hypocalcemiasecondary hyperparathyroidism phosphaturia, demineralization of bones  disease.

Risk factors Exclusively breast feeding Incorrect diet Sun protection Malabsorption syndromes Liver diseases. Kidney diseases Prematurity. Medications Antacids Anticonvulsants Corticosteroids Loop diuretics Malignancy

CLINICAL FEATURES peak incidence 6 months – 2 years irritability profuse sweating while asleep hypotonia frequent respiratory infections. failure to thrive delay in walking, delayed dentition fits, tetany, seizures constipation slowed growth and development progressive loss of muscle tone and strength, muscle cramps

ACUTE SIGNS Have acute and subacute clinical signs Craniotabes – acute sign of rickets, osteolyses detected by pressing firmly over the occipital or posterior parietal bones, ping-pong ball sensation will be felt. Large anterior fontanella, with hyperflexible borders, cranial deformation with asymmetric occipital flattening.

SUBACUTE SIGNS Subacute signs are all the following: frontal and temporal bossing False closure of sutures (increase protein matrix), in the X-ray craniostenosis is absent. Maxilla in the form of trapezium, abnormal dentition. Late dental evolution, enamel defects in the temporary and permanent dentition. Enlargement of costo-chondral junctions-“rickets rosary” Thorax, sternum deformation, softened lower rib cage at the site of attachment of the diaphragm- Harrison groove

Subacute signs Spinal column- scoliosis, lordosis, kyphosis. Pelvis deformity, entrance is narrowed (add to cesarean section in females) Extremities- palpated wrist expansion from rickets, tibia anterior convexity, bowlegs or knock kness legs. Deformities of the spine, pelvis and legs result in reduced stature, rachitic dwarfism. Delayed psychomotor development (heat holding, sitting, standing due to hypotonia).

SIGNS HEAD Larger than normal. Frontal bossing (due to excess osteoid) Craniotabes (ping pong ball sensation) due to thinning of outer table of skull. Delayed closure of anterior fontanel Caput quadratum (square like head)

THOREX Rachitic Rosery (prominent costochondral junctions) Harrison’s sulcus (depression above the subcostal margin at the site of diaphragm) Pulling of softened ribs by the diaphragm during inspiration. Pigeon chest deformity. (The weakened ribs bend inwards due to the pull of respiratory muscles and causing anterior protrusion of sternum).

Extremities 1. Widening of wrists and ankles 2. Bending of long bones results in bow legs, knock knees (genu valgum, tibiae vara) 3. Green stick fractures

Widening of wrist joints

Widening of ankle joints

X-ray of a 20 month old boy with rickets Notice the bow shape of the legs.

Radiological findings Only in difficult diagnostic cases. X-ray of the distal ulna and radius: concave (cupping) ends; normally sharply, Fraying rachitic metaphyses and a widened epiphyseal plate. Osteoporosis of clavicle, costal bones, humerus. Greenstick fractures. Thinning of the cortex, diaphysis and the cranial bones.

Radiological Changes Rx Vitamin D3 + Calcium

LAB DATA 1.Serum Calcium low (normal 9-11mg/dl) 2.Serum phosphorus low (normal-5-7mg/dl) 3.Alkaline phosphatase is raised. This is the most striking feature, shows increased but ineffective activity of osteoblasts. 4. 25-(OH) D levels less than 20 ng/dl confirms of Vitamin D deficiency

Why are we seeing this comeback? The easiest way for our bodies to get vitamin D is from exposure to sunlight. Fear of cancer Increased use of sun-blockers Use of sun protective clothing Fear of aging effects caused by the sun

Why are we seeing the comeback? Increased rates of breastfeeding One of the few things breast milk is deficient in…vitamin D (?!?) Infant formula is supplemented with vitamin D Mothers are themselves short on supply and vitamin D….therefore so is their milk. Poor compliance of prenatal vitamins Avoidance of dairy products/fortified cereals by mother for whatever reason Neither feeding partner is getting ‘normal’ amounts of sun exposure (fear of aging/cancer) Failure to supplement or lack of adherence to recommendations

Why are we seeing this comeback? Increased rate of near-term (late-preterm) infants Lack of or poor prenatal care Infants do not receive the boost normally given to the infant in the last few weeks of pregnancy….if there their mother has ample stores. Increased rates of exclusively breastfeeding. Little if any sun exposure

Treatment 1000 Int. Units daily for infants less than 1 month of age. 1000 to 5000 Int. Units daily for infants 1-12 months of age. 5000 Int. Units daily for infants greater than one year of age Continue this initial therapy until radiologic evidence of healing…~3 months Then reduce dose to 400 Int. Units daily.

PREVENTION To prevent rickets, health experts recommend a child should be breast-fed weaned and put on to cow's milk and other foods rich in vitamin D and calcium, like eggs and dairy products such as butter and leafy vegetables. fish

PREVENTION 1.Exposure to sunlight (ultraviolet light) Early morning and evening 30 minutes per week or 2 hours per week maintains adequate sun exposure. 2.Food fortified with Vit A and Vit D specially butter and milk. Children under 5 should 500ml of milk daily or youghart or cheese daily.

PREVENTION Daily intake of 400 i.u.vitamin D by supplemention. Lactating mothers should receive supplemention with milk or vitamin D to ensure prevention of rickets in their babies. Sun exposure to mothers.

Vitamin D- dependent rickets Type I - pseudovitamin D-deficiency rickets (Deficinecy of renal 25(OH)D3-1-alpha-hdroxylase Type II -hereditary 1-alpha, 25-dihydroxyvitamin D-resistant rickets (Defective interaction between calcitriol and receptor)

Vitamin D-resistant rickets Familial hypophosphatemic rickets or X-linked hypophosphatemic rickets (impaired proximal renal tubular reabsorption of phosphorus and inappropriately normal calcitriol levels ) Hereditary hypophosphatemic rickets with hypercalciuria (Impaired proximal renal tubular reabsorption of phosphorus and increased calcitriol )