Rickets

Rickets, also known as rachitis, is a condition resulting in weak or soft bones in children due to dietary deficiency or genetic causes. Common symptoms include bowed legs, stunted growth, bone pain, a large forehead, and trouble sleeping.

Complications can include bone fractures, muscle spasms, abnormally curved spine, and intellectual disability.

The onset typically occurs in childhood, between 3 and 18 months old.

Cause

The primary cause of rickets is a vitamin D deficiency, which might stem from insufficient dietary intake, inadequate sun exposure, or exclusive breastfeeding without vitamin D supplementation. Other contributing factors include celiac disease, certain genetic conditions, and maternal deficiencies during pregnancy. Vitamin D is very important for calcium and phosphorus absorption, and its deficiency results in improper bone mineralisation.

Signs and Symptoms

Signs and symptoms can include bone tenderness, susceptibility to fractures, and early skeletal deformities such as craniotabes (soft, thinned skull bones). Young children may exhibit bowed legs and thickened ankles and wrists, while older children might develop knock knees. Spinal curvatures like kyphoscoliosis or lumbar lordosis, and pelvic bone deformities, may also be present. The condition known as rachitic rosary, characterised by thickening at the costochondral joints, may occur. Hypocalcaemia can lead to tetany, and dental problems are also common. Radiographs typically show bowed legs and a deformed chest, with long-term consequences including permanent bone deformities.

Diagnosis

Diagnosis involves blood tests showing low calcium, low phosphorus, and high alkaline phosphatase levels, alongside radiographic imaging. Radiographs typically reveal changes such as cupping, fraying, and splaying of metaphyses, particularly at sites of rapid growth like the knees, wrists, and ankles.

Treatment

Diet and Sunlight

Treatment involves increasing dietary intake of calcium, phosphates, and vitamin D. Exposure to ultraviolet B light, cod liver oil, and fortified foods are all effective sources of vitamin D. Recommendations suggest 400 IU of vitamin D daily for infants and children. Vitamin D3 (cholecalciferol) is preferred over D2 (ergocalciferol) due to better absorption. Supplementation can be essential, especially for those with limited sun exposure.

Supplementation

Sufficient vitamin D levels can also be achieved through dietary supplementation. The American Academy of Paediatrics (AAP) recommends vitamin D supplementation for all infants, particularly those exclusively breastfed, until they consume sufficient vitamin D-fortified milk or formula. However, evidence from recent reviews indicates limited benefits of vitamin D plus calcium, or calcium alone, in improving rickets.

Surgery

In severe cases, surgery may be required to correct persistent deformities, particularly around the knees. Surgical options include osteotomies or guided growth surgery. Guided growth surgery, which involves gradual correction, has largely replaced corrective osteotomies.

Epidemiology

Rickets is relatively rare in developed countries, with an incidence of less than 1 in 200,000. However, it remains prevalent in the Middle East, Africa, and Asia. Recent reports indicate a resurgence of rickets in England, with hospitalizations at their highest in 50 years.

History

The condition was first noted by Greek physician Soranus of Ephesus in the 1st and 2nd centuries AD. It was formally described by English physician Daniel Whistler in 1645 and further detailed by Francis Glisson in 1650. The use of ultraviolet lamps to treat rickets was demonstrated by Kurt Huldschinsky in 1918-1919, and the role of diet was clarified by Edward Mellanby between 1918 and 1920. Harry Steenbock's work in 1923 on ultraviolet irradiation of foodstuffs significantly contributed to the prevention of rickets.

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Self-assessment MCQs (single best answer)

What is the primary cause of rickets?

Which of the following is not a common symptom of rickets?

At what age does rickets typically onset in children?

Which diagnostic finding is commonly associated with rickets?

What is the role of vitamin D in the body that affects rickets?

Which of the following treatments is not typically used for rickets?

Which form of vitamin D is preferred due to better absorption?

What skeletal deformity is characterised by thickening at the costochondral joints in rickets?

Which population is most at risk of developing rickets?

In which regions is rickets still prevalent today?