Causes

The most common cause of vitamin D deficiency is insufficient intake of vitamin D from food, or insufficient formation of vitamin D by sunlight. This occurs particularly in the dark autumn and winter months. Dark skinned people living in Germany are also particularly often affected by a vitamin D deficiency, as their dark skin (a lot of melatonin) reduces the formation of vitamin D. For this reason dark-skinned humans need the 10-50-fache quantity more at UV-B-RADIATION than light-skinned humans, in order to form the same quantity of Vitamin D. Also affected by a vitamin D deficiency are people who only rarely expose themselves to sunlight (e.g.

bedridden patients), or people whose skin only receives little sunlight due to veiled clothing (e.g. burqas). Other causes of vitamin D deficiency are digestive and intestinal absorption disorders (maldigestion, malabsorption) in the context of various diseases such as celiac disease and celiac sprue, Crohn’s disease or alcoholism. It is not uncommon for medication to be the cause of a vitamin D deficiency.

Typical examples are loop diuretics (which cause increased excretion of calcium), glucocorticoids or calcitonin. But also kidney or liver diseases with kidney and liver failure can cause a vitamin D deficiency due to insufficient vitamin D formation. Also during the pregnancy an additional need at Vitamin D is necessary, why lack symptoms are frequent. However, it is essential to compensate for these deficiencies in order to avoid later developmental damage to the unborn child.

Symptoms

Symptoms of vitamin D deficiency can be numerous. They most frequently affect bones, hair and teeth. But the nervous system is also frequently affected by its deficiency symptoms.

In adults, the main symptom of vitamin D deficiency can be osteomalacia, a softening of the bones with subsequent skeletal deformation, or osteoporosis (bone loss), in which the bones are slowly broken down and thus become brittle. The leading symptom of vitamin D deficiency in children is the world-renowned rickets, a bone mineralization disorder in which brittle, inferior bones are formed that begin to bend as the children grow. The comparable clinical picture in adults is called osteomalacia.Typical symptoms of rickets are, apart from general symptoms such as fatigue, restlessness, headaches and increased irritability, above all skeletal changes, which can occur as early as the 3rd month of life.

These include a spinal curvature, the classic knock-knees or bow legs (genova valga or vara), a depression of the lateral skull bone when light finger pressure is applied (craniotabes), flabby abdominal muscles that generate the classic image of a “frog’s belly”, as well as muscle weakness, cramps and a tendency to tetany (involuntary strong muscle tension). Other typical symptoms of a vitamin D deficiency are a reduced immune defence, which leads to increased infections, delayed tooth eruption with enamel defects and caries, since healthy teeth, like bones, are dependent on vitamin D. The diagnosis of rickets in children is usually made by a good anamnesis and a clinical examination, which is followed by an X-ray and a blood test. X-rays show changes typical of rickets, such as the “Rickets’ Rosary”, which stands for cartilage bulges at the rib borders.

A blood test reveals an increase in parathyroid hormone, a decrease in 25-hydroxyl-calcitriol (active form of vitamin D) and an increase in alkaline phosphatase, which is significant for disorders of bone metabolism or for liver and bile duct diseases. Therapy for rickets in children would be the high-dose administration of vitamin D3 in the form of tablets for several weeks. Parallel to the prophylaxis of a sudden calcium deficiency, calcium should also be given.

The skeletal changes are usually reduced after vitamin D administration after a few weeks. Subsequently, however, care should be taken to ensure an adequate supply of sunlight or a further dose of vitamin D3. Rickets have become rare in Germany today, but despite this there are still children who suffer from a severe vitamin D deficiency. This often affects dark-skinned children of immigrants who have not received adequate vitamin D prophylaxis in their home country and who are unable to produce sufficient vitamin D in Germany due to their dark skin color.

Diagnosis
Therapy