rickets

Rickets

Description of Disease

Rickets is a disease that is characterized by a decrease in bone density. This reduction is due to a decrease in the rate of osteoid synthesis to a level that is insufficient to compensate normal bone lysis. There is diminished calcification in the cartilage of the growth plate of the bone. There are many different types of Rickets that affect the population but all types are based on a deficiency. The differentiating factor in diagnosing the type of Rickets lies within the acquisition or the type of patients in which the disease appears.

Vitamin D Deficiency

This type occurs in infants and children, which is a result of a lack of sun exposure and vitamin D in their diet. Vitamin D deficiency Rickets is not very common in the present day and is most commonly seen in breastfed babies that have a limited exposure to sunlight. Premature babies may form neonatal rickets, which results in spontaneous fractures, impaired growth, and respiratory distress. Neonatal rickets is usually seen within the first 8 to 10 weeks of life and is diagnosed with a chest x-ray. The radiographic appearance could show fractured ribs or just softened which would result in the ribs having an irregular and frayed appearance. Vitamin D deficiency rickets may appear in patients that have disorders of the small bowel, abnormalities of the hepatobiliary system, or gastrointestinal malabsorption problems. Intestinal surgery can also cause rickets by decreasing the mineralization of the bones. A related deficiency is the deficiency of 25(OH) Vitamin D that occurs in patients with neonatal hepatitis, biliary atresia, liver disease, anticonvulsant therapy, and vitamin-D-dependent rickets. A patient with renal osteodystrophy may develop rickets due to the deficiency of 1,25(OH2) vitamin D.

Etiology

Rickets is caused by a lack of Vitamin D and other factors contribute to the cause of the
disease. The main factors are the ratios and quantities of calcium and phosphorus available in the body, the speed and growth of the individual, and the ultraviolet ray filtering power of the
atmosphere (Evans, 1994). Vitamin D has three different forms: vitamin D, 25(OH) vitamin D, and 1,25(OH2) vitamin D. These vitamins come from sunlight therefore, if a person receives an
insufficient amount of sunlight, they could be at risk for developing Rickets.

Signs and Symptoms

Weakening and deformity of the bones

Fatigue

Infants may suffer respiratory distress

Few symptoms before the advanced stage

Diagnosis

The most effective way to diagnose Rickets is through the evaluation of x-rays. The
early stages of the disease will be noticeable in the distal ends of the radius and ulna. The ulna
will show significant changes will the radius appears to be normal. The main changes are the irregular fraying of the provisional zone of calcification. It is normally sharply defined, however, with Rickets it becomes fuzzy and fades into the soft tissue density of the adjacent cartilage (Evans, 1994). Radiographic findings will show abnormal increased axial height of the cartilaginous portion of the epiphyseal plate while cupping and widening of the ends of the long bones. Flat bones such as the skull or sternum may have an appearance of decreased density and become deformed and thin in children.

Treatment and Prognosis

The main treatment for Rickets is with vitamin D therapy. One type of treatment is a single day therapy, stosstherapy, which is one large dose of vitamin D. Stosstherapy is used for patients with nutritional vitamin D deficiency. The response of this treatment is usually within 5 to 7 days. Vitamin D and calcium doses are also a common treatment for Rickets. Almost all patients are cured after treatment but in some severe cases there may be residual deformities. The patient may still suffer from bowing of the bones, knock knees, pathological fractures, or saber shin. The majority of treated Rickets patients will go on to live normal and unaffected lives. The main aspect that must be considered is the cause for the vitamin defect and then the disease can be accurately and effectively treated. The prognosis for Rickets patients is remarkable if treated.

References

Eisenberg, Ronald L. and Cynthia A. Dennis, (1995) Comprehensive Radiographic Pathology: Second Edition. St. Louis, MS: Mosby Inc.

Finberg, L. & BR. Shah. Single-day therapy for nutritional vitamin D-deficiencies rickets. Journal of Pediatrics. 125, 487-490.

Kaplan, FS. Osteopetrorickets. Pathophysiology and Treatment. Clinical Orthopaedics & Related Research. 294, 64-78.

Rabinowitz, Jack. Skeletal Radiology, (1992) Kingsport; Mc-Graw Companies.