Introduction

Rickets is softening of bones in children and can be defined as a consequence of the vitamin D deficiency and may occur due to calcium and phosphorus metabolic disorders. Blood analysis shows hypocalcemia and hypophosphatemia. Histologically, there is Failure in mineralisation of the bone and cartilaginous tissues and clinically it manifests as skeletal growth disorder.

Risk factors

·       Living in northern latitudes (>30°);

·       Dark skinned children;

·       Decreased exposure to sunlight (polluated geographical areas, humid climate)

·       Maternal vita min, Ddeficiency;

·       Diets low in calcium, phosphorus and vitamin D, e.g. exclusive breast-feeding into late infancy, toddlers on unsupervised "dairy-free" diets;

·       Macrobiotic, strict vegan diets;

·       High phytic acid diet, e.g. chapattis;

·       Prolonged parenteral nutrition in infancy with an inadequate supply of intravenous calcium and phosphate;

·       Intestinal malabsorption: defective production of 25 (OH) D3 - liver disease. Increased metabolism of 25 (OH) D3 - enzyme induction by anticonvulsants;

Defective production of 1,25 (OH) 2133

·       Hereditary type I vitamin D-resistant (or dependent) rickets (mutation which abolishes activity of renal hydroxylase);

·       Familial (X-linked) hypophosphataemic rickets - renal tubular defect in phosphate transport;

·       Chronic renal disease;

·       Fanconi syndrome (renal loss of phosphate)

·       Target organ resistance to 1,25 (OH)2D3- hereditary vitamin D-dependent rickets type II (due to mutations in vitamin D receptor gene).

Calcium deficiency rickets can be classified in to 3 grades- I, II, Ill, Depending on the duration, evolution and the complication:

1.                Grade I, II, III; evolution acute, subacute, recidivant.

2.                Depending on vitamin D insufficiency:

•                          Diet

•                          Infections

•                          Food diversification

•                          Habitual

•                          No prophylaxis

•                          Prophylaxis with low dose

•                          Phenobarbital induced

Rickets may cause

·                    Rickets tetany

·                    Convulsions

·                    Respiratory disorders

·                    Cardiac disorders

·                    Skeletal deformation

·                    Frequent illness

Clinical manifestations:

Rickets may develop in any age of an infant, more frequent at 3-6mo, early in prematures.

·                 The first signs of hypocalcaemia are CNS changes- excitation, restlessness, excessive sweated during sleep and feeding, tremors of the chin and extremities.

·                 Skin and muscle changes- pallor, occipital alopecia, fragile nails and hair, muscular hypotony, motor retardation.

·                 Complications- apnoea, stridor, low calcium level with neuromuscular irritability (tetany).

·                 CNS changes are sometimes interpreted as CNS trauma and the administration of the Phenobarbital which activates the hepatic enzyme may deactivates Vit. D and within 1 - 2wk of the treatment with Phenobarbital the clinical stage worsens.

Acute Signs

Have acute and subacute clinical signs

Craniotabes - acute sign of rickets, osteolyses detected by pressing firmly over the occipital or poster 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.

•                          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, bowl 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)

Investigations

·       Serum calcium level (N=2.2-2.ómmol/l). At the level <2.0mmol/I convulsions sets in.

·       Phosphorus normal (1 .5-1 .8mmol/l). Normal ratio of Ca: P= 2:1; in rickets become 3:1; 4:1.

·       Serum 25 (OH) D3 (N=28+2.1 ng/ml) ; and 1,25 (OH) 2133 (N=0.035+0.003ng/ml)

·       Serum alkaline phosphatase is elevated >500mmol/l.

·       Thyrocalcitonin can be appreciated (N =23.6+3 .3pM/l)

·       Serum parathyroid hormone (N=598+5.OpM/l)

·       In urine: Aminoaciduria >1 .0mg/kg/day Urinary excretion of 35' cyclic AMP

Decreased calcium excretion (N =50-1 5Omg/24h)

X-   Rays

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.

Genu Varum deformity at knees.

·       Osteoporosis of clavicle, costal bones, humerus. Rickety Rosary at chest. Pigeon chest.

·       Green stick fractures.

·       Thinning of the cortex, diaphysis and the cranial bones.

Prophylaxis in Rickets

Specific antenatal prophylactic dose administration : 500-1 000IU/day of vitamin D3 solution at the 28-th week of pregnancy. The total dose administered is 135000-180000IU. In term infants prophylactic intake of vitamin D2 700IU/d started at 10 days of age during the first 2 years of life; in premature the dose may increase to 1 000IU/day.

WHO recommendation for rickets prophilaxis in a children coming from unfavorable conditions and who have difficult access to hospitals is 200000IU vitamin D2 intramuscular, On the 7day, 2, 4, 6 month- total dose 800000IU. In case of the necessary prolongation 700IU/day till 24mo are given.

Treatment of Rickets

The treatment is with vitamin D3 depending on the grade.

·       In grade I- 2000-4000IU/day for 4-óweeks, totally 120000-180000IU.

·       In grade II- 4000-6000IU/day for 4-óweeks, totally 1 80000-230000IU.

·       In grade III- 8000-1 2000IU/day for 6-8 weeks, totally 400000-700000IU.

·       Along with vitamin D, calcium is also administered (40 mg/kg/day for a term baby,

·       80 mg/kg/dayfora premature baby) ; also indicate vitamin B&C preparations.

·       From the 7-th day of the treatment massage can be started. Intramuscular administration of ATP solution in case of myotonia 1 ml/day is preferred.

Specific splints may be required to correct or to control the deformities in early stages. In We stages, when deformities have established, surgery may be required, especially for bow legs.

Patients must be encouraged for sun-bathing