Pathological osteolysis: When the bone dissolves
Osteolysis refers to the physiological bone metabolism the process of bone removal that is normally in equilibrium with the bone formation (Osteogenesis), or with the natural aging process gradually increases. A pathological importance is attached to the osteolysis is a disease-related bone dissolution, or bone decomposition varying degrees and due to various causes. It often occurs in connection with osteoporosis, or bone marrow cancer osteolytic processes. In addition to the treatment of the underlying disease is of great importance to the administration of drugs from the group of bisphosphonates, the bone removal to counteract.
Table of contents
A brief Overview
The following Overview of the most important facts provides a brief summary of the following comprehensive article
- Definition: As osteolysis is the physiological process of Bone breakdown known, the so-called osteoclasts (phagocytic cells) and a part of the natural bone remodeling process. A pathological importance of the concept of osteolysis gets only when a pathologically increased bone resorption.
- Causes and underlying conditions: An active bone resorption is due to various disorders or diseases, such as osteoporosis or bone(marrow)cancer. But there are also forms, without any discernible trigger. The diverse causes as the conditions for the Occurrence of different forms and manifestations of bone decomposition.
- Symptoms: The symptoms of the various manifestations and diseases is highly variable. In the advanced stage of various bone or joint pain may occur. Unstable made the bones easier to break and discomfort of a calcium surplus (due to the release of calcium in the bone removal process) can be the result.
- Diagnosis: in addition to the classical x-ray examination can nuclear medical procedures, such as a skeleton or bone marrow scintigraphy imaging, a possible osteolysis and its sequelae provide information.
- Treatment: The treatment depends primarily on the underlying disease and its symptoms. In addition, bisphosphonates are often used to protect the bone substance and to inhibit their degradation.
First of all, the osteolysis refers to the natural physiological process of bone removal that is normally in equilibrium with the bone formation (Osteogenesis). This so-called bone remodelling is a process in a healthy person the important functions to the maintenance and constant renewal and adjustment of our bones and skeletal system.
For the bone removal, the osteoclasts are on a cellular level. These are controlled by hormones of bone metabolism and act as a bone-destructive “eating cells”. This decomposition process, the activity of bone building in the same extent osteoblasts. It comes as a result of various causes to disorders of this process, it can get a pathological significance. In such cases, one speaks of an active bone resorption, or abnormal bone resolution.
Causes and underlying diseases
The body builds more bone tissue, this need not lead to a General bone loss in the sense of a pathogenic osteolysis. The natural aging process, due for example to a shift of the equilibrium in bone metabolism. From the age of about 50 years, more bone removal processes take place, therefore, even in healthy people, as a whole, in turn, new bone substance is built up.
The causes of a pathogenic osteolysis are very diverse and can diseases caused by various disorders in the body, other reason, or without an identifiable trigger to occur.
Disorders of bone remodelling
In the sense of an abnormal increase in Bone resorption relative to bone formation, this can occur in very different disturbance processes, and diseases. A relatively widespread disease, which is associated with a loss of bone tissue, osteoporosis (bone loss). In this osteopathy (bone disease), premature or accelerated bone loss that leads to a reduction in the organic and mineral bone substance, and thus to brittle bones. Often hormonal causes are rash, especially in women after the Menopause.
In addition, it also comes in the appearance of a Osteomalcia in reduced bone mass. In contrast to osteoporosis, the reduction of the bone substance is concentrated in the mineral fraction. Usually a calcium deficiency, in combination with a Vitamin D deficiency, or a disorder of Phosphate metabolism, in this context, the triggering factor.
These bone diseases can be systemic, that is, it is all bones can be affected.
The other reason can be diseases, a local loss of bone substance. Local osteoclasts überakti activities have the effect of a spatially limited degradation processes. This is commonly referred to as a circumscribed osteolysis. This disease usually caused holes in the bone, which can act dancing.
As a trigger for such processes, many diseases are considered. Including bone tumors or bone cysts, chronic inflammatory diseases (chronic Polyarthritis, Osteomyelitis), or even hormonal disorders, for example.
It is cancer as a trigger, can come in both benign as well as malignant bone tumors in question. But also cancer of other organs or a malignant hematological tumours, such as various leukemias (white blood cancer), can lead to a circumscribed osteolysis.
Another disease that can be associated with a local bone removal, the isolated Form of Multiple myeloma is called plasmacytoma. This is a lymphoma disease, a malignant Tumor of the lymphocytes (bone marrow cancer). The typical image of the punched holes is formed at the locations where the tumor cells in the bone grow. Often this is in the area of the skull, and speaks in this context of a “Schrotschussschädel“.
Rare metabolic diseases or hormonal disorders are the cause. Triggers for about an Overactive parathyroid gland (hyperparathyroidism) osteolytic changes, this can, among other things, in the jaw and facial area occur.
In addition, the bone loss in the area of endoprostheses or implants occur (periprosthetic osteolysis). A permanent foreign body contact between the bone and the Material used can lead to abrasion and thus to the loss of their own bone substance. This can lead to a loosening of the prosthesis or of a dental implant. In addition, inflammatory processes and immune system reactions to infection can lead to bone degradation processes – not only in the areas of the prostheses.
Also, such processes can be observed in the area of bone trauma and fractures, and this is due to interference in the healing process. Harmful traumas can, for example, in the case of excessive weight lifting in the shoulder area (
Very rarely, the so-called idiopathic Osteolysis can occur. In these forms, the causes are unknown. One of these rare diseases, the phantom bone disease (Gorham-Stout syndrome), where it comes to the full resolution of a single bone.
According to different classifications, other rare hereditary (inheritable) idiopathic Osteolysis are described. Including the multicentric osteolysis with or without nephropathy (kidney disease). This syndrome occurs, as a rule, already as a child, when it comes to a progressive loss of bone with increasing age. Master Hand and the tarsal bones are affected. As a result, it is due to bone deformation to physical restriction of movement. Sometimes mental deficits and abnormalities in the face.
Possible symptoms depend on the cause or underlying disease and its localization. Often, symptoms occur only in advanced stages of the disease, and it will show up not infrequently rather uncharacteristic Symptoms, not attributable to easily and clearly.
A bone resolution is already at an advanced stage, the affected bones to become unstable and as a result easier to break bones (fractures). In addition, the process releases increased calcium, which can lead to a calcium excess (hypercalcemia). An example of this is the osteolytic hypercalcemia in a plasmacytoma. The complaints in the case of increased calcium levels in the blood are of a different nature. In addition to calcium deposits in various organs (For example, the kidney) can occur, among other things, the following symptoms:
- Nausea and vomiting,
- Muscle weakness,
- Heart rhythm disorders,
- an inflammation of the pancreas,
- frequent urination,
- mental impairment (lack of concentration, Depression).
May also different types of pain occur in the affected bones and areas of the body. These are often described as a strain pain, chronic pain or rheumatism-type joint pain.
The diagnosis is based mainly on the causes and triggering disease and the age and the personal information of the Concerned about possible complaints.
Mostly classic x-ray examinations are over, this Osteolysis is instructive. Fracture risk areas, and existing fractures can be localized by means of x-ray images. Bone cancer is the cause of the decomposition processes in a specific radio can be given a logical character notes, whether it is a benign or malignant Tumor.
Also, methods of investigation of the nuclear medicine can help, and even disintegration of the bones to prove it. However, a high sensitivity of the examination for the various osteolyt is not given in every case, processes. Appropriate opportunities for the Skelettszintigrafe (bone scintigraphy) or bone marrow scintigraphy. A scintigraphy of the skeleton represents the local bone metabolism that may be increased in some diseases at an early stage. In the case of the bone marrow scintigraphy, the blood is imaged bone marrow, which may also have very small cases of Osteolysis, which can arise for example due to tumor spread.
The concept of therapy depends on the underlying disease, to the extent that this could be diagnosed, and varies accordingly.
Often drug therapy with bisphosphonates is used as a Supplement to other treatment approaches. These drugs (for example, Pamidronate, or Zolendronat) to inhibit osteoclast activity by forming a kind of protective layer around the bone. As a result, the progression can be delayed to the end of bone loss and fracture risk can be reduced.
In addition, the active ingredients interfere with the Calcium metabolism, so that a hypercalcemia with harmful deposition processes of calcium is countered in other organs. The desired result occurs, be indirectly alleviated pain. In principle, the parties Concerned may choose between intravenous infusions or taking it in tablet form. Is sometimes applied instead of the corresponding Bisphosponate also Calcetonin (for example, synthetic salmon Calcitonin).
Also in the field of Naturopathy, various measures can be used to Supplement. Here are the recommendations, as well, in the first line according to the clinical picture of the causative disease. (tf, cs; updated on 27.11.2018)