Rare systemic bone diseases
Diseases other than osteoporosis/Miller’s disease
Osteogenesis imperfecta (brittle bone disease) is caused by gene defects in the collagen gene. It not only occurs during childhood; occasionally, it only manifests itself during adulthood.
Osteoscleroses are bone diseases involving increased bone density but fragile bones. These include osteopetrosis, a genetic disease involving defective osteoclasts.
Osteopoikilosis is randomly diagnosed on X-ray images and is clinically inconspicuous. Fluoridosis is endemic due to increased fluoride concentrations in drinking water or iatrogenic due to incorrect treatment. Typical characteristics include pain in the lower extremities; the bone density is increased but so is the fracture rate.
Paget’s disease is characterised by honeycombed bones; one (frequently e.g. the tibia) or several bones (pelvis, skull, etc.) are affected. Its genesis is unclear; its incidence is decreasing worldwide. Patients complain of pain and the skin over the affected bone is excessively warm. Bisphosphonates or denosumab are used in therapy.
Fibrous dysplasia is caused by a gene defect in the GNAS gene; the polyostotic form is also called Jaffé-Lichtenstein syndrome. McCune-Albright syndrome occurs in combination with endocrinopathies. The bones have a washed-out appearance that resembles frosted glass.
Melorheostosis is an impressive random finding from X-ray images. It is also referred to as Leri’s disease. Therapy is not usually necessary.