IS Case 382: Rickets
2009 URMC Imaging Sciences
Publication Date: 2010-03-02
Patient is a 9-month-old female with poor feeding and failure to thrive. Outpatient physical exam is consistent with rickets, and patient is found to have elevated alkaline phosphatase and low calcium and Vitamin D.
PA and oblique views of the left wrist demonstrate irregularity of the distal metaphysis of the radius and ulna. These areas are frayed and splayed in a manner consistent with rickets. Similar findings are noted in the metaphysis of the distal femur and proximal tibia on left knee radiographs. A chest radiograph shows cupping and splaying of the anterior ribs, in the "rachitic rosary" (beading of the ribs) pattern. These studies also demonstrate diffuse osteomalacia.
Rickets is the skeletal manifestation of a group of disorders caused by the absolute or relative deficiency of Vitamin D. Vitamin D deficiency can be secondary to dietary deficiency, malabsorption, renal disease, or lack of end organ response. It can also be secondary to calcium deficiency, which in turn leads to vomiting and diarrhea which causes Vitamin D deficiency. Although not common in Western countries, rickets affects many of the malnourished children of developing nations.
Vitamin D deficiency results in insufficient ossification, or mineralization, of growing cartilage. This leads to the build up of nonossified osteoid, and can best be seen radiographically in the rapidly growing bones of the knees and wrists. Radiographs of these areas will demonstrate fraying and cupping of the metaphyses with irregularity along the physeal margin. There may also be generalized osteomalacia, and patients with rickets are prone to insufficiency fractures and slipped capital femoral epiphysis.
Symptoms can include bone pain, muscle weakness, skeletal deformity (bow legs, knock knees, scoliosis), and frequent fractures to name a few. Radiographs in conjunction with levels of calcium, vitamin D, and alkaline phosphatase are used for diagnosis.
Treatment includes dietary modification, supplementation and sunlight.
- Donnelly LF. Pediatric Imaging: The Fundamentals. Saunders, 2009:195-6.