Osteosclerosis describes a hardening of the bones due to various causes. In this process, there is an excessive increase in bone substance. However, the stability of the bones is impaired.
What is osteosclerosis?
Osteosclerosis is not a single disease. The term describes only the changes in bone toward hardening and increase in bone mass. Despite considerable bone density, the bone architecture is not stable. Frequent bone fractures occur and, depending on the underlying disease, further ossification may occur. There are both genetic causes of osteosclerosis and secondary bone hardening due to an underlying disease. In most cases, osteosclerosis is generalized. That is, the entire skeleton is affected by the disease process. However, there are also cases with localized osteosclerosis. Especially in the primary form of bone hardening, a genetic defect can almost always be assumed as the cause. This form of the disease is very rare. Secondary osteosclerosis is more common and occurs especially in renal insufficiency. However, there is also a form with increased intake of fluorides through food. This form also belongs to secondary osteosclerosis. Localized forms of osteosclerosis may result from malignant or benign bone tumors or in Paget’s disease.
Causes
There are several causes for the development of osteosclerosis. Bone hardening is part of the outward appearance of the symptom, with a steady increase in bone mass but a decrease in bone stability. Hardening of the bone can take place on the basis of the increase of the inorganic material, the organic component or both components. In some cases, complicated and uneven remodeling processes occur. In other cases, only bone formation takes place without remodeling processes. For example, in hereditary osteopetrosis (marble bone disease), bone is only built up without any remodeling processes. As a rule, the precursors of the bone cells consist of osteoblasts and osteoclasts. The osteoblasts are responsible for building bone, while the osteoclasts are to break down excess bone material. A constant remodeling process must take place within the bones in order to constantly remodel the bones. However, this is not the case in osteopetrosis. Another hereditary osteosclerosis is Engelmann syndrome. Here, irregular bone growth occurs with increasing bone hardening and loss of stability of the bones. In melorheostosis, although bone metabolism is unimpaired, irregular growth causes thickening of the bones in some areas, especially the extremities. In this case, it looks as if the bones are flowing. This disease is also caused by a genetic defect. More often, secondary osteosclerosis develops in the context of renal insufficiency. The condition, known as renal osteodystrophy, is a very complex disorder of bone growth. Renal insufficiency causes vitamin D hormone metabolism to be impaired. Calcium and phosphate are no longer retained and are increasingly excreted. The resulting hypocalcemia causes a higher concentration of parathyroid hormone, which in turn leads to demineralization of the bone. To compensate for the demineralization, more connective tissue-like bone material is formed. The bone mass increases. At the same time, however, there is a loss of stability.
Symptoms, complaints, and signs
The courses of the individual diseases vary. However, a common symptom is considered to be a constant increase in bone mass and, at the same time, a decrease in bone stability. The accompanying symptoms depend on the underlying disease. For example, osteopetrosis is characterized by increased bone fragility, liver and spleen enlargement, immune deficiency, convulsions, and cranial nerve damage. There are also diseases characterized by multiple dysplasias in addition to osteosclerosis, such as the genetic Lenz-Majewski syndrome. Secondary renal osteodystrophy is notable for bone and joint pain and swelling. Bone fragility is increased. Simultaneously, muscle atrophy also occurs. External calcifications are found on the joints in the elbow, shoulder joints, knees, toes or finger joints.These are redeposited at the edge of the bones due to increased calcium dissolution processes within the bones. This causes pain that severely restricts mobility. Calcium deposits can also occur in the arteries, causing arterial occlusive disease with all its consequences.
Diagnosis and course of the disease
The diagnosis of osteosclerosis is strongly based on the underlying disease or disorder. When severe renal disease is evident, the character of the disease is examined diagnostically in the overall context. If hereditary disease is suspected, human genetic testing can be performed. However, this requires an intensive anamnesis of the family medical history beforehand. If local osteosclerosis is present, investigations should also be performed in the direction of tumor.
Complications
Due to osteosclerosis, patients suffer from decreased stability of the bones. Thus, it is not uncommon for even minor injuries to result in fractures or other injuries to the bones. For this reason, patients with osteosclerosis must avoid accidents and impacts at all costs, as the healing of the bones is also impaired. Furthermore, it is not uncommon for those affected to have a significantly weakened immune system and also cramps in the muscles. The liver and spleen are significantly enlarged, so pain can occur in these regions. Furthermore, the weakened immune system leads to more frequent infections and inflammations. Without treatment, this can also lead to damage to the brain, which is usually irreversible and should be avoided at all costs. Furthermore, there are symptoms in the joints and arterial occlusion can occur. As a rule, a causal treatment of osteosclerosis takes place. No particular complications occur, but a tumor may have to be removed. Furthermore, patients require chemotherapy in this process, which usually takes place with side effects.
When should one go to the doctor?
If there is pain in the bones or problems moving the hands and feet, a doctor should be consulted. The symptoms indicate osteosclerosis, which must be clarified quickly to avoid an increase in symptoms and long-term consequences. Affected persons should consult a physician if the above-mentioned signs of the disease do not recede on their own or increase in intensity within a short period of time. Medical advice is required at the latest when the typical joint noises occur. The physician can quickly determine osteosclerosis on the basis of imaging procedures and a medical history and, if necessary, initiate treatment directly or refer the patient to a specialist. People who have already had a bone infection or an inflammation of the bone belong to the risk groups. They should confer with the physician in charge if the symptoms described occur and do not subside on their own. Close medical supervision is also necessary after bone injuries, contact with toxic substances and bone cancer. In addition to the family doctor, the orthopedist or a specialist in internal medicine can be consulted. In cooperation with nutritional physicians and genetic counseling centers, the cause of osteosclerosis can be determined. During therapy, physiotherapists, sports physicians and other specialists are involved in the treatment.
Treatment and therapy
The therapy of an existing osteosclerosis depends on the cause. The hereditary diseases cannot be treated causally. Only symptomatic treatments are possible here. This includes constant monitoring and also treatment of any fracture that may have occurred. If a tumor is diagnosed, surgical measures are of course necessary. If the tumor is malignant, chemotherapy and radiotherapy follow. Renal osteodystrophy can only be treated as part of the overall therapy of the kidney disease. If fluorosis is found to be present, discontinuation of heavy fluoride intake is sufficient.
Outlook and prognosis
The prognosis of osteosclerosis is based on the stage at which the disease is detected and treated and the type of osteosclerosis involved. If the condition is left untreated, the ossification may increase and cause various health problems over the course of a lifetime.Initially, the load-bearing capacity of the bones is reduced, causing the patient to accept various limitations. There is no prospect of complete recovery. Existing hardening of the bone tissue can only be reduced by complex procedures. The prognosis is determined by the orthopedic specialist. Depending on the form and severity of the disease, he or she will involve other physicians if necessary. Since osteosclerosis develops in episodes and usually cannot be treated causally, the prognosis must be regularly adjusted to the patient’s current state of health. Thanks to modern medicine, the prospect of a symptom-free life is relatively high. Life expectancy is usually not limited by osteosclerosis. However, there is an increased risk of obesity, cardiovascular problems and falls. In the secondary form of osteosclerosis, there are also serious underlying diseases such as cancer or kidney disease, which can reduce quality of life and life expectancy.
Prevention
A general recommendation for prevention from osteosclerosis cannot be given. The causes are very diverse and rarely depend on lifestyle. Only to prevent fluorosis should attention be paid to normal fluoride intake.
Follow-up
In most cases of osteosclerosis, affected individuals have very few and usually limited measures of direct aftercare available. For this reason, affected individuals should seek medical attention for this disease at a very early stage to prevent the occurrence of further complications and symptoms. It is not possible for the disease to heal on its own, so those affected should always consult a doctor. Most of those affected are usually dependent on a surgical procedure to remove the tumor. The earlier this operation takes place, the better the further course of the disease. After such an operation, the affected person should in any case rest and take it easy, refraining from exertion or from stressful and physical activities. Most patients are also dependent on the support and help of their own family during the treatment. Loving and intensive conversations also have a positive effect on the further course of osteosclerosis and thus also prevent psychological upsets or depression. In some cases, osteosclerosis also reduces the life expectancy of the affected person.
Here’s what you can do yourself
Individuals diagnosed with osteosclerosis can take some steps to promote recovery and make daily living with the disease easier. First, however, it is important to follow the physician’s guidelines regarding diet and physical activity. Patients should work with a nutritionist to establish a diet and follow it consistently. Although this will not cure the bone disease, an individually adapted diet will reduce pain and increase the well-being of those affected. The same applies to exercise and a regular daily routine with sufficient sleep and little stress. Any movement restrictions must be compensated for by aids such as walking aids or prostheses. Patients should consult a specialist at an early stage and take the necessary steps. Accompanying this, constant monitoring and treatment of any fractures is necessary in any case. If osteosclerosis is due to a malignant tumor, chemotherapy or radiotherapy is indicated. This can be supported by sparing and physiotherapy. If fluorosis is causative, it is sufficient to discontinue the triggering foods or medications and to take it easy on the body for a few weeks.
