Classification
Brittle bone disease can be divided into different subtypes, each of which has its own characteristics. They often differ in the stature of the affected persons, as well as in the expression of symptoms and the course of the disease. Type I (type Lobstein): Type I of the brittle bone disease is the mildest form of the disease.
It is often only diagnosed when the child is already older and is noticeably prone to fractures. However, the diagnosis may be made even later when accompanying symptoms become noticeable, such as hearing problems in adulthood. Those affected usually have few skeletal abnormalities.
Their joints are usually extremely mobile and their muscles are rather weak. The sclerae can be discolored bluish. Otherwise, type I is inconspicuous.
Type II: Type II brittle bone disease is the most severe form of the disease. Patients are extremely prone to fractures and suffer from an underdeveloped lung. In the past, this form of brittle bone disease was considered to be unviable, but nowadays it can be treated more effectively, which can extend survival time.
Nevertheless, many children suffer multiple fractures during birth, which is why they often die within the first 24 hours after birth. The insufficient maturity of the lungs is also a decisive factor in the premature death of the young patients. Type III (Type Vrolik): Patients with type III of vitreous bone disease also suffer from a severe form of the disease.
They are small in stature and have many skeletal deformations that occur both in the extremities and the spine. This can also affect breathing. Often these patients are dependent on a wheelchair.
Type IV: Type IV can be regarded as a lighter form of Type III. These patients are also small, but suffer less from skeletal deformities and do not need a wheelchair as often as type III patients.The sclerae of those affected can be normal, but also bluish discolored. Type V: Patients with type V vitreous bone disease experience the phenomenon of excessive callus formation.
After fractures, excessive new bone formation occurs, resulting in thickening of the bone. In these patients, calcium also accumulates in the ligament structures between ulna and radius, and between tibia and fibula. This leads to problems with the inward and outward rotation of these body parts.
This can already give an indication of the underlying disease during the examination. Type VI: Patients with type VI have normal to bluish sclera. They show typical symptoms of the brittle bone disease.
The special feature, however, is that no genetic cause for the symptoms can be found in these patients. They do not have the typical genetic mutations as the other patients with vitreous bone disease. Type VII: The special characteristic of patients with vitreous bone disease type VII is the so-called rhizomellia.
Here, the upper arm and thigh bones are relatively short compared to the lower arm and lower leg bones. The therapy of vitreous bone disease is based on three main pillars: Physiotherapy, intramedullary nailing and bisphosphonates. Since the brittle bone disease is genetically determined, it is not yet curable.
The therapy only serves to improve the symptoms. Physiotherapy: Physiotherapy is becoming increasingly important in the treatment of brittle bone disease. Immobility promotes further loss of bone mass, so targeted physiotherapeutic exercises are beneficial to stabilize bones at risk of fracture.
This also prevents particularly bad posture, as the muscles are built up. If possible, physiotherapy should be performed daily. It is also advisable to perform the exercises in water.
Patients can move easily and there is no danger of falling or fractures. Intramedullary nailing: Intramedullary nailing serves to directly stabilize the bones. For this purpose, the corresponding bone is divided into several pieces during an operation.
The pieces are then threaded onto a nail or wire like a string of pearls, so that the original, axially correct position of the bone is restored. In this way, bone deformities following fractures can be avoided. Telescopic nails that can be pulled apart and thus do not hinder growth can also be used for this purpose.
This means that the nails do not have to be changed so often due to insufficient length. However, intramedullary nailing must not be performed on patients in poor general condition. Nor can it be used if there is too little bone substance, because the nail then does not have enough hold in the bone.
Bisphosphonates: The treatment of vitreous bone disease with bisphosphonates is a drug therapy approach. Bisphosphonates are preparations that inhibit bone-destroying cells and thus lead to a secondary increase in bone substance. This can reduce the fracture rate in patients. Bone pain also occurs less frequently under bisphosphonate therapy.
