In congenital disorders of vitamin D metabolism, developmental disorders of the bones already occur in utero and in the growing organism. Acquired disorders, on the other hand, lead to reduced mineralization in the already formed bone with a tendency to bending and spontaneous fractures. The classical picture of vitamin D deficiency is rickets in infants and adolescents on the one hand and osteomalacia in adults on the other. Rickets
Rickets is a vitamin D deficiency disease of the infant or adolescent. This metabolic disorder is caused by inadequate intestinal absorption and renal reabsorption of calcium and phosphate. The first signs of rickets are:
- Low calcium and phosphate concentrations.
- Increased serum alkaline phosphatase activity.
- Secondary hyperparathyroidism in response to low serum calcium levels (5-7 mg/100 ml).
Due to the insufficient absorption of calcium and phosphate in the bones, there is insufficient mineralization demineralization of the skeleton. As a result, the structure of the hard bone substance is disturbed. The bones become soft and easily deformable, resulting in the classic changes in the bones (bone bending, such as genoa vara). Clinical symptoms of rickets
- Rachitic rosary in the area of the sternum sternum (distension of the cartilage-bone junction of the ribs).
- Persistent bone curvature (especially spinal curvature) or deformations of the skeleton, mainly in the area of the sternum as well as rib cage, but also the skull, spine scoliosis, kyphosis and legs.
- Atypical heart-shaped pelvis
- Alopecia totalis inflammatory hair loss disease in the congenital forms of rickets.
- In the growing organism, there is an increase in thickness, especially in the joint area, which is due to a corresponding overload of the epiphyses
- Calcium deficiency leads in addition to secondary hyperparathyroidism to tetany cramps of the muscles of the extremities (paw position), hypersensitivity of the nervous system and cerebral seizures, such as epileptic and narcoleptic seizures, respectively
Finally, rickets causes disturbances in the length growth of bones, bone pain, dental problems, muscle atrophy and increased risk of fracture. Rickets is more common both in immigrant children of color from developing countries who do not receive vitamin D prophylaxis and in children who are fed a macrobiotic diet. Osteomalacia
Osteomalacia is the equivalent of rickets in adulthood, because this metabolic disorder does not develop until the skeleton is fully grown. Osteomalacia is also characterized by a mineralization disorder of bone, which leads to bone softening with corresponding skeletal changes osteoidosis of bone.Due to collagen formation, there is an abnormally high ratio of soft bone matrix to mineralized bone. Clinical symptoms of osteomalacia.
- Increased osteoporosis in genetic predisposition.
- Muscular weakness
- Diffuse bone pain affected mainly chest, shoulders, spine, pelvis and legs
- As the disease progresses, spontaneous fractures, especially of the pelvic ring, may occur
- Calcium deficiency leads to secondary hyperparathyroidism and tetany.
Other symptoms of vitamin D deficiency
Hypovitaminosis D
Hypovitaminosis D is a clinical syndrome, which occurs mainly in elderly and bedridden people. However, young individuals and people in countries beyond 40 years of latitude also frequently suffer from hypovitaminosis D.
- Changes in respiratory functions
- Decreased immune function
- Changes in muscle metabolism, such as decreased muscle strength and tone, impaired control of muscle activity, resulting in an increased tendency for older people to fall, with the risk of femoral neck fractures
- Increased body sway due to impaired neuromuscular coordination also increases the tendency to fall and thus the risk of fracture