Melorheostosis is a progressive condition characterized by the thickening of the cortical bone. This rare disorder also affects the bone and the soft tissue growth and their development. This condition causes the severe functional limitation among the affected cases and presents deformity, soft tissue contractures and chronic pain. Melorheostosis is considered to occur during fetal development but the symptoms may not become evident until later childhood or early adulthood. The prevalence of melorheostosis is estimated at 1 in 1,000,000 individuals with around 400 cases reported in medical literature.
Causes
The exact cause of melorheostosis is not known. A small number of individuals belonging to the family who had osteopoikilosis or Buschke-Ollendorff syndrome have this condition. The genetic mutation in the gene LEMD3 has been identified to be the cause of the syndromes osteopoikilosis or the Buschke-Ollendorff syndrome. This gene is responsible for the coding of the protein that is part of the nuclear membrane which plays the essential inhibitory role in bone development. Melorheostosis is considered to be a sporadic condition that is not inherited but believed to be the result of a randomly occurring genetic mutation affecting the subset of body tissues.
Symptoms
The symptoms of melorheostosis vary among the affected case. The onset of symptoms occurs in late childhood or early adulthood. Commonly, this condition affects the lower limbs although the arms and the hands can also be involved. On rare cases, the spinal column, ribs and the skull are also affected. Most of the cases experience pain that is rarely constant or severe. The hardening of the skin and the tissues of the affected bone can result in stiffness and when this condition involves the joints, it can cause joint contracture presenting limited joint movement. In some cases, it can also affect the normal growth presenting short stature.
Diagnosis
Among the children, the diagnosis is possible with the limb length discrepancies, angular bone deformities, thickening of the skin and joint contractures. The x-rays in children indicate the streaking on the inside of the bone. The diagnosis of melorheostosis among adults is based on the x-rays findings that present the characteristic features such as the thickened bone (sclerotic bone lesions) linked to the flowing, melted candle.
Treatment
The treatment for melorheostosis is limited but is focused on providing relief from the symptoms. No form of a single treatment option is completely effective for all the cases. The treatment can consist of physical therapy, hydrotherapy and medications to alter the bone remodeling process. The surgery for the bone deformity, joint contractures, hardened surroundings soft tissues has been performed with variable results. Surgery may also be necessary as the treatment option for the limb length discrepancy. The chronic pain management can be challenging and can include medications such as non-steroidal anti-inflammatory drugs and rarely narcotics. The limited movement of the joints (contracture) can be hard to treat which can be permanent.
References
https://rarediseases.info.nih.gov/diseases/9474/melorheostosis
https://rarediseases.org/rare-diseases/melorheostosis/
http://www.paleyinstitute.org/orthopedic-conditions/melorheostosis/melorheostosis
http://boneandspine.com/what-is-melorheostosis/
