Osteosclerosis is a disorder that is characterized by abnormal hardening of bone and an elevation in bone density. It may predominantly affect the medullary portion and/or cortex of bone. Plain radiographs are a valuable tool for detecting and classifying osteosclerotic disorders. It can manifest in localized or generalized osteosclerosis. Localized osteosclerosis can be caused by Legg–Calvé–Perthes disease, sickle-cell disease and osteoarthritis among others. Osteosclerosis can be classified in accordance with the causative factor into acquired and hereditary.
|Sclerosis of the bones of the pelvis due to prostate cancer metastases|
Osteosclerosis can be detected with a simple radiography. There are white portions of the bone which appear due to the increased number of bone trabeculae.
In the animal kingdom there also exists a non-pathological form of osteosclerosis, resulting in unusually solid bone structure with little to no marrow. It is often seen in aquatic vertebrates, especially those living in shallow waters, providing ballast as an adaptation for an aquatic lifestyle. It makes bones heavier, but also more fragile. In those animal groups osteosclerosis often occurs together with bone thickening (pachyostosis). This joint occurrence is called pachyosteosclerosis.
Achondroplasia is a genetic disorder that results in dwarfism. In those with the condition, the arms and legs are short, while the torso is typically of normal length. Those affected have an average adult height of 131 centimetres (4 ft 4 in) for males and 123 centimetres (4 ft) for females. Other features include an enlarged head and prominent forehead. Intelligence is generally normal.Achondroplasia is due to a mutation in the fibroblast growth factor receptor 3 (FGFR3) gene. In about 80% of cases this occurs as a new mutation during early development. In the other cases it is inherited from one's parents in an autosomal dominant manner. Those with two affected genes do not typically survive. Diagnosis is generally based on symptoms, but may be supported by genetic testing if uncertain.Treatments may include support groups and growth hormone therapy. Efforts to treat or prevent complications such as obesity, hydrocephalus, obstructive sleep apnea, middle ear infections, or spinal stenosis may be required. Life expectancy of those affected is about 10 years less than average. The condition affects about 1 in 27,500 people. Rates are higher in Denmark and Latin America. The shortest known adult with the condition is Jyoti Amge at 62.8 centimetres (2 ft 0.7 in).Bednar's aphthae
Bednar's aphthae is a type of oral ulceration (mouth ulcers) which occurs in infants. The lesions are located on the palate and are caused by trauma. No treatment is required since the lesions heal within a few days.The condition was first described in 1850, by the Austrian physician Alois Bednar (1816-1888).Condensing osteitis
Condensing osteitis is a periapical inflammatory disease that results from a reaction to a dental related infection. This causes more bone production rather than bone destruction in the area (most common site is near the root apices of premolars and molars). The lesion appears as a radiopacity in the periapical area hence the sclerotic reaction. The sclerotic reaction results from good patient immunity and a low degree of virulence of the offending bacteria. The associated tooth may be carious or contains a large restoration, and is usually associated with a non-vital tooth. It was described by Dr. Carl Garré in 1893.Crescent sign
In radiology, the crescent sign is a finding on conventional radiographs that is associated with avascular necrosis. It usually occurs later in the disease, in stage III of the four-stage Ficat classification system. It appears as a curved subchondral radiolucent line that is often found on the proximal femoral or humeral head. Usually, this sign indicates a high likelihood of collapse of the affected bone. The crescent sign may be best seen in an abducted (frog-legged) position.The crescent sign is caused by the necrotic and repair processes that occur during avascular necrosis. Osteosclerosis occurs at a margin where new bone is placed over dead trabeculae. When the trabeculae experience stress leading to microfractures and collapse, the crescent sign appears.The crescent sign may be seen with other bone diseases, such as shear fractures.Foix–Alajouanine syndrome
Foix–Alajouanine syndrome is a disorder caused by an arteriovenous malformation of the spinal cord. The patients present with symptoms indicating spinal cord involvement (paralysis of arms and legs, numbness and loss of sensation and sphincter dysfunction), and pathological examination reveals disseminated nerve cell death in the spinal cord and abnormally dilated and tortuous vessels situated on the surface of the spinal cord. Surgical treatment can be tried in some cases. If surgical intervention is contraindicated, corticosteroids may be used.
The condition is named after Charles Foix and Théophile Alajouanine.Idiopathic osteosclerosis
Idiopathic osteosclerosis is a condition which may be found around the roots of a tooth. It is usually painless and found during routine radiographs. It appears as a radiopaque (light area) around a tooth, usually a premolar or molar. There is no sign of inflammation of the tooth.Lipodystrophy
Lipodystrophy syndromes are a group of genetic or acquired disorders in which the body is unable to produce and maintain healthy fat tissue. The medical condition is characterized by abnormal or degenerative conditions of the body's adipose tissue. ("Lipo" is Greek for "fat", and "dystrophy" is Greek for "abnormal or degenerative condition".) A more specific term, lipoatrophy, is used when describing the loss of fat from one area (usually the face). This condition is also characterized by a lack of circulating leptin which may lead to osteosclerosis. The absence of fat tissue is associated with insulin resistance, hypertriglyceridemia, non-alcoholic fatty liver disease (NAFLD) and metabolic syndrome.List of diseases (O)
This is a list of diseases starting with the letter "O".Melanocytic oral lesion
Melanocytic oral lesions are an extremely uncommon condition characterized by pigmented lesions of the mucous membranes.Osteochondrodysplasia
Osteochondrodysplasia or skeletal dysplasia is a general term for a disorder of the development (dysplasia) of bone ("osteo") and cartilage ("chondro").Osteochondrodysplasias are rare diseases. About 1 in 5,000 babies are born with some type of skeletal dysplasia. Nonetheless, if taken collectively genetic skeletal dysplasias or osteochondrodysplasias comprise a recognizable group of genetically determined disorders with generalized skeletal affection. Osteochondrodysplasias can result in marked functional limitation and even mortality. Osteochondrodysplasias subtypes can overlap in clinical aspects. Therefore, plain radiography is absolutely necessary to establish an accurate diagnosis. Magnetic resonance imaging can provide further diagnostic insights and guide treatment strategies especially in cases of spinal involvement. Early diagnosis, and timely management of skeletal dysplasia are important to combat functional deterioration.Osteoma
An osteoma (plural: "osteomata") is a new piece of bone usually growing on another piece of bone, typically the skull. It is a benign tumor.
When the bone tumor grows on other bone it is known as "homoplastic osteoma"; when it grows on other tissue it is called "heteroplastic osteoma".
Osteoma represents the most common benign neoplasm of the nose and paranasal sinuses. The cause of osteomata is uncertain, but commonly accepted theories propose embryologic, traumatic, or infectious causes. Osteomata are also found in Gardner's syndrome. Larger craniofacial osteomata may cause facial pain, headache, and infection due to obstructed nasofrontal ducts. Often, craniofacial osteoma presents itself through ocular signs and symptoms (such as proptosis).Osteopetrosis
Osteopetrosis, literally "stone bone", also known as marble bone disease, or Albers-Schönberg disease is an extremely rare inherited disorder whereby the bones harden, becoming denser, in contrast to more prevalent conditions like osteoporosis, in which the bones become less dense and more brittle, or osteomalacia, in which the bones soften. Osteopetrosis can cause bones to dissolve and break.It is one of the hereditary causes of osteosclerosis. It is considered to be prototype of osteosclerosing dysplasias. The cause of the disease is understood to be malfunctioning osteoclasts, and its inability to resorb bone. Although human osteopetrosis is a heterogeneous disorder encompassing different molecular lesions and a range of clinical features, all forms share a single pathogenic nexus in the osteoclast. The exact molecular defects or location of the mutations taking place are unknown. Osteopetrosis was first described in 1903, by a German radiologist Albers-Schönberg.Pachyosteosclerosis
Pachyosteosclerosis is a combination of thickening (pachyostosis) and densification (osteosclerosis) of bones. It makes bones more heavy, but also more fragile. The condition often occurs in aquatic vertebrates, especially those living in shallow waters, creating ballast as an adaptation for maintaining neutral buoyancy and horizontal trim. It is in no way pathological. To resist bend, it frequently is found especially in ventral bones, whereas concentration near the lungs helps in maintaining trim.
Examples of animals showing pachyosteosclerosis are seacows (dugongs and manatees), the extinct Plesiosauria and Mesosauria and extinct aquatic sloths.Pachyostosis
Pachyostosis is a non-pathological condition in vertebrate animals in which the bones experience a thickening, generally caused by extra layers of lamellar bone. It often occurs together with bone densification (osteosclerosis), reducing inner cavities. This joint occurrence is called pachyosteosclerosis. However, especially in the older literature, "pachyostosis" is often used loosely, referring to all osseous specializations characterized by an increase in bone compactness and/or volume. It occurs in both terrestrial and, especially, aquatic or semi-aquatic vertebrates.In aquatic animals, such as seacows (manatees and dugongs), Thalassocnus, and plesiosaurs, it provides (or provided) ballast as an adaptation for an aquatic existence.
Most giant deer showed pronounced pachyostosis of the mandible and skull. It has been suggested that this served to store minerals for antler growth. Many Pachycephalosauria and most members of the Dinocephalia clade of therapsids had thickened skull bones, probably used in head-butting contests.Raine syndrome
Raine syndrome (RNS), also called osteosclerotic bone dysplasia, is a rare autosomal recessive congenital disorder characterized by craniofacial anomalies including microcephaly, noticeably low set ears, osteosclerosis, a cleft palate, gum hyperplasia, a hypoplastic nose, and eye proptosis. It is considered to be a lethal disease, and usually leads to death within a few hours of birth. However, a recent report describes two studies in which children with Raine Syndrome have lived to 8 and 11 years old, so it is currently proposed that there is a milder expression that the phenotype can take (Simpson 2009).
It was first characterized in 1989 in a report that was published on an infant that had been born with an unknown syndrome, that later came to be called Raine Syndrome.The current research describes Raine Syndrome as a neonatal osteosclerotic bone dysplasia, indicated by its osteosclerotic symptoms that are seen in those suffering from the disease. It has been found that a mutation in the gene FAM20C is the cause of the Raine Syndrome phenotype. This microdeletion mutation leads to an unusual chromosome 7 arrangement. The milder phenotypes of Raine Syndrome, such as those described in Simpson’s 2007 report, suggest that Raine Syndrome resulting from missense mutations may not be as lethal as the other described mutations (OMIM). This is supported by findings from Fradin et al. (2011), who reported on children with missense mutations to FAM20C and lived to ages 1 and 4 years, relatively much longer than the life spans of the previously reported children. Simpson et al.’s (2007) report states that to date, effected individuals have had chromosome 7 uniparental isodisomy and a 7p telomeric microdeletion. They had abnormal chromosome 7 arrangements, with microdeletions of their D7S2477 and D7S1484 markers (Simpson 2007).
Raine Syndrome appears to be an autosomal recessive disease. There are reports of recurrence in children born of the same parents, and an increased occurrence in children of closely related, genetically similar parents. Individuals with Raine Syndrome were either homozygous or compound heterozygous for the mutation of FAM20C. Also observed have been nonsynonomous mutation and splice-site changes (Simpson et al. 2007).
FAM20C, located on chromosome 7p22.3, is an important molecule in bone development. Studies in mice have demonstrated its importance in the mineralization of bones in teeth in early development (OMIM, Simpson et al. 2007, Wang et al. 2010). FAM20C stands for “family with sequence similarity 20, member C.” It is also commonly referred to as DMP-4. It is a Golgi-enriched fraction casein kinase and an extracellular serine/threonine protein kinase. It is 107,743 bases long, with 10 exons and 584 amino acids (Weizmann Institute of Science).Sclerosis (medicine)
Sclerosis is the stiffening of a structure, usually caused by a replacement of the normal organ-specific tissue with connective tissue. The structure may be said to have undergone sclerotic changes or display sclerotic lesions, which refers to the process of sclerosis. The term is from Greek σκληρός "hard".
Common medical conditions whose pathology involves sclerosis include:
Amyotrophic lateral sclerosis, sometimes known as Lou Gehrig's disease, a progressive, incurable, usually fatal disease of motor neurons.
Atherosclerosis, a deposit of fatty materials, such as cholesterol, in the arteries which causes hardening.
Focal segmental glomerulosclerosis is a disease that attacks the kidney's filtering system (glomeruli) causing serious scarring and thus a cause of nephrotic syndrome in children and adolescents, as well as an important cause of kidney failure in adults.
Hippocampal sclerosis, a brain damage often seen in individuals with temporal lobe epilepsy.
Lichen sclerosus, an autoimmune disease that hardens the connective tissues of the vagina and the penis.
Multiple sclerosis, or focal sclerosis, is a central nervous system disease which affects coordination.
Osteosclerosis, a condition where the bone density is significantly increased, resulting in decreased lucency on radiographs.
Otosclerosis, a disease of the ears.
Systemic sclerosis (progressive systemic scleroderma), a rare, chronic disease which affects the skin, and in some cases also blood vessels and internal organs.
Tuberous sclerosis, a rare genetic disease which affects multiple systems.
Primary sclerosing cholangitis, a hardening of the bile duct by scarring and repeated inflammation.
Primary lateral sclerosis, progressive muscle weakness in the voluntary muscles.Skeletal fluorosis
Skeletal fluorosis is a bone disease caused by excessive accumulation of fluoride in the bones. In advanced cases, skeletal fluorosis causes painful damage to bones and joints.Trumpeter's wart
A trumpeter's wart is a cutaneous condition characterized by a firm, fibrous, hyperkeratotic nodule on the upper lip of a trumpet player.Worth syndrome
Worth syndrome, also known as benign form of Worth hyperostosis corticalis generalisata with torus platinus, autosomal dominant osteosclerosis, autosomal dominant endosteal hyperostosis or Worth disease, is a rare autosomal dominant congenital disorder that is caused by a mutation in the LRP5 gene. It is characterized by increased bone density and benign bony structures on the palate.
Bone and joint disease (M80–M94, 730–733)
Osteochondrodysplasia (Q77–Q78, 756.4–756.5)