Rickets
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Rickets is a condition that results in weak or soft
bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
s in children, and is caused by either dietary deficiency or genetic causes. Symptoms include
bowed legs Genu varum (also called bow-leggedness, bandiness, bandy-leg, and tibia vara) is a varus deformity marked by (outward) bowing at the knee, which means that the lower leg is angled inward ( medially) in relation to the thigh's axis, giving the ...
,
stunted growth Stunted growth is a reduced growth rate in human development. It is a primary manifestation of malnutrition (or more precisely undernutrition) and recurrent infections, such as diarrhea and helminthiasis, in early childhood and even before birth ...
, bone pain, large forehead, and trouble sleeping. Complications may include bone deformities, bone pseudofractures and fractures,
muscle spasms A spasm is a sudden involuntary contraction of a muscle, a group of muscles, or a hollow organ such as the bladder. A spasmodic muscle contraction may be caused by many medical conditions, including dystonia. Most commonly, it is a muscle c ...
, or an abnormally curved spine. The most common cause of rickets is a
vitamin D deficiency Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D defic ...
, although hereditary genetic forms also exist. This can result from eating a diet without enough
vitamin D Vitamin D is a group of fat-soluble secosteroids responsible for increasing intestinal absorption of calcium, magnesium, and phosphate, and many other biological effects. In humans, the most important compounds in this group are vitamin D3 (c ...
, dark skin, too little sun exposure, exclusive
breastfeeding Breastfeeding, or nursing, is the process by which human breast milk is fed to a child. Breast milk may be from the breast, or may be expressed by hand or pumped and fed to the infant. The World Health Organization (WHO) recommends that br ...
without vitamin D supplementation,
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...
, and certain genetic conditions. Other factors may include not enough
calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
or
phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
. The underlying mechanism involves insufficient
calcification Calcification is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue,Miller, J. D. Cardiovascular calcification: Orbicular origins. ''Nature Mat ...
of the
growth plate The epiphyseal plate (or epiphysial plate, physis, or growth plate) is a hyaline cartilage plate in the metaphysis at each end of a long bone. It is the part of a long bone where new bone growth takes place; that is, the whole bone is alive, wi ...
. Diagnosis is generally based on blood tests finding a
low calcium Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mmo ...
, low phosphorus, and a high alkaline phosphatase together with
X-rays An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10 Picometre, picometers to 10 Nanometre, nanometers, corresponding to frequency, ...
. Prevention for exclusively breastfed babies is vitamin D supplements. Otherwise, treatment depends on the underlying cause. If due to a lack of vitamin D, treatment is usually with vitamin D and calcium. This generally results in improvements within a few weeks. Bone deformities may also improve over time. Occasionally surgery may be performed to correct bone deformities. Genetic forms of the disease typically require specialized treatment. Rickets occurs relatively commonly in the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
,
Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...
, and
Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...
. It is generally uncommon in the United States and Europe, except among certain
minority group The term 'minority group' has different usages depending on the context. According to its common usage, a minority group can simply be understood in terms of demographic sizes within a population: i.e. a group in society with the least number o ...
s. It begins in childhood, typically between the ages of 3 and 18 months old. Rates of disease are equal in males and females. Cases of what is believed to have been rickets have been described since the 1st century, and the condition was widespread in the
Roman Empire The Roman Empire ( la, Imperium Romanum ; grc-gre, Βασιλεία τῶν Ῥωμαίων, Basileía tôn Rhōmaíōn) was the post-Republican period of ancient Rome. As a polity, it included large territorial holdings around the Mediterr ...
. The disease was common into the 20th century. Early treatments included the use of
cod liver oil Cod liver oil is a dietary supplement derived from liver of cod fish (Gadidae). As with most fish oils, it contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and also vitamin A and vitamin D. Histori ...
.


Signs and symptoms

Signs and symptoms of dietary deficiency rickets can include
bone A bone is a Stiffness, rigid Organ (biology), organ that constitutes part of the skeleton in most vertebrate animals. Bones protect the various other organs of the body, produce red blood cell, red and white blood cells, store minerals, provid ...
tenderness, and a susceptibility for bone
fracture Fracture is the separation of an object or material into two or more pieces under the action of stress. The fracture of a solid usually occurs due to the development of certain displacement discontinuity surfaces within the solid. If a displa ...
s, particularly
greenstick fracture A greenstick fracture is a fracture in a young, soft bone in which the bone bends and breaks. Greenstick fractures occur most often during infancy and childhood when bones are soft. The name is by analogy with green (i.e., fresh) wood which simil ...
s. Early skeletal deformities can arise in infants such as soft, thinned skull bones – a condition known as craniotabes, which is the first sign of rickets;
skull bossing Skull bossing is a descriptive term in medical physical examination indicating a protuberance of the skull, most often in the frontal bones of the forehead ("frontal bossing"). Although prominence of the skull bones may be normal, skull bossing m ...
may be present and a delayed closure of the fontanelles. Young children may have
bowed legs Genu varum (also called bow-leggedness, bandiness, bandy-leg, and tibia vara) is a varus deformity marked by (outward) bowing at the knee, which means that the lower leg is angled inward ( medially) in relation to the thigh's axis, giving the ...
and thickened ankles and wrists; older children may have
knock knees Knock may refer to: Places Northern Ireland * Knock, Belfast, County Down * Knock, County Armagh, a townland in County Armagh Republic of Ireland * Knock, County Clare, village in County Clare * Knock, County Mayo, village in County Mayo * ...
. Spinal curvatures of
kyphoscoliosis Kyphoscoliosis describes an abnormal curvature of the spine in both a coronal and sagittal plane. It is a combination of kyphosis and scoliosis. This musculoskeletal disorder often leads to other issues in patients, such as under-ventilation of ...
or lumbar
lordosis Lordosis is historically defined as an ''abnormal'' inward curvature of the lumbar spine. However, the terms ''lordosis'' and ''lordotic'' are also used to refer to the normal inward curvature of the lumbar and cervical regions of the human spi ...
may be present. The
pelvic bone The hip bone (os coxae, innominate bone, pelvic bone or coxal bone) is a large flat bone, constricted in the center and expanded above and below. In some vertebrates (including humans before puberty) it is composed of three parts: the ilium, isch ...
s may be deformed. A condition known as
rachitic rosary The prominent knobs of bone at the costochondral joints of rickets patients are known as a rachitic rosary or beading of the ribs. The knobs create the appearance of large beads under the skin of the rib cage, hence the name by analogy with the bea ...
can result as the thickening caused by nodules forming on the
costochondral joint The costochondral joints are the joints between the ribs and costal cartilage in the front of the rib cage. They are hyaline cartilaginous joints (i.e. synchondrosis or primary cartilagenous joint). Each rib has a depression shaped like a cup t ...
s. This appears as a visible bump in the middle of each rib in a line on each side of the body. This somewhat resembles a rosary, giving rise to its name. The deformity of a pigeon chest may result in the presence of
Harrison's groove Harrison's groove, also known as Harrison's sulcus, is a horizontal groove along the lower border of the thorax corresponding to the costal insertion of the diaphragm; it is usually caused by chronic asthma or obstructive respiratory disease. It m ...
.
Hypocalcemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6  mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mm ...
, a low level of calcium in the blood can result in
tetany Tetany or tetanic seizure is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disorders that increase the action potential frequency of muscle cells or the nerves that innervate them. Muscle cramps caus ...
– uncontrolled muscle spasms. Dental problems can also arise. An
X-ray An X-ray, or, much less commonly, X-radiation, is a penetrating form of high-energy electromagnetic radiation. Most X-rays have a wavelength ranging from 10  picometers to 10  nanometers, corresponding to frequencies in the range 30&nb ...
or
radiograph Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeut ...
of an advanced patient with rickets tends to present in a classic way: the bowed legs (outward curve of long bone of the legs) and a deformed chest. Changes in the skull also occur causing a distinctive "square headed" appearance known as "caput quadratum". These deformities persist into adult life if not treated. Long-term consequences include permanent curvatures or disfiguration of the long bones, and a curved back.


Cause

Maternal deficiencies may be the cause of overt bone disease from before birth and impairment of bone quality after birth. The primary cause of congenital rickets is
vitamin D deficiency Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D defic ...
in the mother's blood, which the baby shares. Vitamin D ensures that serum phosphate and calcium levels are sufficient to facilitate the mineralization of bone. Congenital rickets may also be caused by other maternal diseases, including severe
osteomalacia Osteomalacia is a disease characterized by the softening of the bones caused by impaired bone metabolism primarily due to inadequate levels of available phosphate, calcium, and vitamin D, or because of resorption of calcium. The impairment of bon ...
, untreated
celiac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...
,
malabsorption Malabsorption is a state arising from abnormality in absorption of food nutrients across the gastrointestinal (GI) tract. Impairment can be of single or multiple nutrients depending on the abnormality. This may lead to malnutrition and a variety ...
,
pre-eclampsia Pre-eclampsia is a disorder of pregnancy characterized by the onset of high blood pressure and often a significant amount of protein in the urine. When it arises, the condition begins after 20 weeks of pregnancy. In severe cases of the disease ...
, and
premature birth Preterm birth, also known as premature birth, is the birth of a baby at fewer than 37 weeks gestational age, as opposed to full-term delivery at approximately 40 weeks. Extreme preterm is less than 28 weeks, very early preterm birth is between 2 ...
. Rickets in children is similar to osteoporosis in the elderly, with brittle bones. Pre-natal care includes checking vitamin levels and ensuring that any deficiencies are supplemented. Exclusively breast-fed infants may require rickets prevention by vitamin D supplementation or an increased exposure to sunlight. In sunny countries such as Nigeria, South Africa, and Bangladesh, there is sufficient endogenous vitamin D due to exposure to the sun. However, the disease occurs among older toddlers and children in these countries, which in these circumstances is attributed to low dietary calcium intakes due to a mainly cereal-based diet. Those at higher risk for developing rickets include: * Breast-fed infants whose mothers are not exposed to sunlight * Breast-fed infants who are not exposed to sunlight * Breast-fed babies who are exposed to little sunlight * Adolescents, in particular when undergoing the pubertal growth spurt * Any child whose diet does not contain enough vitamin D or calcium Diseases causing soft bones in infants, like
hypophosphatasia Hypophosphatasia (; also called deficiency of alkaline phosphatase, phosphoethanolaminuria, or Rathbun's syndrome; sometimes abbreviated HPP) is a rare, and sometimes fatal, inherited metabolic bone disease. Clinical symptoms are heterogeneous, ...
or
hypophosphatemia Hypophosphatemia is an electrolyte disorder in which there is a low level of phosphate in the blood. Symptoms may include weakness, trouble breathing, and loss of appetite. Complications may include seizures, coma, rhabdomyolysis, or softening ...
, can also lead to rickets.
Strontium Strontium is the chemical element with the symbol Sr and atomic number 38. An alkaline earth metal, strontium is a soft silver-white yellowish metallic element that is highly chemically reactive. The metal forms a dark oxide layer when it is ex ...
is allied with calcium uptake into bones; at excessive dietary levels strontium has a rachitogenic (rickets-producing) action.


Sunlight

Sunlight, especially ultraviolet light, lets human skin cells convert vitamin D from an inactive to active state. In the absence of vitamin D, dietary calcium is not properly absorbed, resulting in
hypocalcaemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6 mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mmol ...
, leading to skeletal and dental deformities and
neuromuscular A neuromuscular junction (or myoneural junction) is a chemical synapse between a motor neuron and a muscle fiber. It allows the motor neuron to transmit a signal to the muscle fiber, causing muscle contraction. Muscles require innervation ...
symptoms, e.g. hyperexcitability. Foods that contain vitamin D include butter, eggs, fish liver oils, margarine, fortified milk and juice, portabella and
shiitake The shiitake (alternate form shitake) (; ''Lentinula edodes'') is an edible mushroom native to East Asia, which is now cultivated and consumed around the globe. It is considered a Medicinal fungi, medicinal mushroom in some forms of tradition ...
mushrooms, and
oily fish Oily fish are fish species with oil (fats) in soft tissues and in the coelomic cavity around the gut. Their fillets may contain up to 30% oil, although this figure varies both within and between species. Examples of oily fish include smal ...
es such as
tuna A tuna is a saltwater fish that belongs to the tribe Thunnini, a subgrouping of the Scombridae (mackerel) family. The Thunnini comprise 15 species across five genera, the sizes of which vary greatly, ranging from the bullet tuna (max length: ...
,
herring Herring are forage fish, mostly belonging to the family of Clupeidae. Herring often move in large schools around fishing banks and near the coast, found particularly in shallow, temperate waters of the North Pacific and North Atlantic Oceans, i ...
, and
salmon Salmon () is the common name for several list of commercially important fish species, commercially important species of euryhaline ray-finned fish from the family (biology), family Salmonidae, which are native to tributary, tributaries of the ...
. A rare
X-linked dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome. As an inheritance pattern, it is less common than the X-linked recessive type ...
form exists called vitamin D-resistant rickets or X-linked hypophosphatemia. Cases have been reported in Britain in recent years of rickets in children of many social backgrounds caused by insufficient production in the body of vitamin D because the sun's ultraviolet light was not reaching the skin due to use of strong
sunblock Sunscreen, also known as sunblock or sun cream, is a photoprotective topical product for the skin that mainly absorbs, or to a much lesser extent reflects, some of the sun's ultraviolet (UV) radiation and thus helps protect against sunburn and ...
, too much "covering up" in sunlight, or not getting out into the sun. Other cases have been reported among the children of some ethnic groups in which mothers avoid exposure to the sun for religious or cultural reasons, leading to a maternal shortage of vitamin D, and people with darker skin need more sunlight to maintain vitamin D levels. Rickets had historically been a problem in
London London is the capital and largest city of England and the United Kingdom, with a population of just under 9 million. It stands on the River Thames in south-east England at the head of a estuary down to the North Sea, and has been a majo ...
, especially during the
Industrial Revolution The Industrial Revolution was the transition to new manufacturing processes in Great Britain, continental Europe, and the United States, that occurred during the period from around 1760 to about 1820–1840. This transition included going f ...
. Persistent thick fog and heavy industrial smog permeating the city blocked out significant amounts of sunlight to such an extent that up to 80 percent of children at one time had varying degrees of rickets in one form or the other. It is sometimes known "the English Disease" in some foreign languages (e.g. German: , Dutch: , Hungarian: ).


Skin color theory

Rickets is often a result of vitamin D3 deficiency. The correlation between human skin color and latitude is thought to be the result of positive selection to varying levels of solar ultraviolet radiation. Northern latitudes have selection for lighter skin that allows UV rays to produce vitamin D from 7-dehydrocholesterol. Conversely, latitudes near the equator have selection for darker skin that can block the majority of UV radiation to protect from toxic levels of vitamin D, as well as skin cancer. An anecdote often cited to support this hypothesis is that Arctic populations whose skin is relatively darker for their latitude, such as the Inuit, have a diet that is historically rich in vitamin D. Since these people acquire vitamin D through their diet, there is not a positive selective force to synthesize vitamin D from sunlight. Environment mismatch: vitamin D deficiency arises from a mismatch between an individual's previous and current environment. This risk of mismatch increases with advances in transportation methods and increases in urban population size at high latitudes. Similar to the environmental mismatch when dark-skinned people live at high latitudes, Rickets can also occur in religious communities that require long garments with hoods and veils. These hoods and veils act as sunlight barriers that prevent individuals from synthesizing vitamin D naturally from the sun. In a study by Mithal et al., vitamin D insufficiency of various countries was measured by lower 25-hydroxyvitamin D. 25(OH) D is an indicator of vitamin D insufficiency that can be easily measured. These percentages should be regarded as relative vitamin D levels, and not as predicting evidence for development of rickets. Asian immigrants living in Europe have an increased risk for vitamin D deficiency. Vitamin D insufficiency was found in 40% of non-Western immigrants in the Netherlands, and in more than 80% of Turkish and Moroccan immigrants. The Middle East, despite high rates of sun-exposure, has the highest rates of rickets worldwide. This can be explained by limited sun exposure due to cultural practices and lack of vitamin D supplementation for breast-feeding women. Up to 70% and 80% of adolescent girls in Iran and Saudi Arabia, respectively, have vitamin D insufficiency. Socioeconomic factors that limit a vitamin D rich diet also plays a role. In the United States, vitamin D insufficiency varies dramatically by ethnicity. Among females aged 70 years and older, the prevalence of low serum 25(OH) D levels was 28.5% for non-Hispanic whites, 55% for Mexican Americans, and 68% for non-Hispanic blacks. Among males, the prevalence was 23%, 45%, and 58%, respectively. A systematic review published in the
Cochrane Library The Cochrane Library (named after Archie Cochrane) is a collection of databases in medicine and other healthcare specialties provided by Cochrane and other organizations. At its core is the collection of Cochrane Reviews, a database of system ...
looked at children up to three years old in Turkey and China and found there was a beneficial association between vitamin D and rickets. In Turkey children getting vitamin D had only a 4% chance of developing rickets compared to children who received no medical intervention. In China, a combination of vitamin D, calcium and nutritional counseling was linked to a decreased risk of rickets. Parents can supplement their nutritional intake with vitamin D enhanced beverages if they feel their child is at risk for vitamin D deficiency. A recent review links rickets disease to exclusive consumption of Neocate baby formula.


Diagnosis

Rickets may be diagnosed with the help of: * Blood tests: ** Serum
calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
may show low levels of calcium, serum
phosphorus Phosphorus is a chemical element with the symbol P and atomic number 15. Elemental phosphorus exists in two major forms, white phosphorus and red phosphorus, but because it is highly reactive, phosphorus is never found as a free element on Ear ...
may be low, and serum alkaline phosphatase may be high from bones or changes in the shape or structure of the bones. This can show enlarged limbs and joints. * A
bone density Bone density, or bone mineral density, is the amount of bone mineral in bone tissue. The concept is of mass of mineral per volume of bone (relating to density in the physics sense), although clinically it is measured by proxy according to optica ...
scan Scan may refer to: Acronyms * Schedules for Clinical Assessment in Neuropsychiatry (SCAN), a psychiatric diagnostic tool developed by WHO * Shared Check Authorization Network (SCAN), a database of bad check writers and collection agency for bad ...
may be undertaken. *
Radiography Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeu ...
typically show widening of the zones of provisional calcification of the
metaphyses The metaphysis is the neck portion of a long bone between the epiphysis and the diaphysis. It contains the growth plate, the part of the bone that grows during childhood, and as it grows it ossifies near the diaphysis and the epiphyses. The metaph ...
secondary to unmineralized osteoid. Cupping, fraying, and splaying of metaphyses typically appears with growth and continued weight bearing. These changes are seen predominantly at sites of rapid growth, including the proximal humerus, distal radius, distal femur and both the proximal and the distal tibia. Therefore, a skeletal survey for rickets can be accomplished with anteroposterior radiographs of the knees, wrists, and ankles.


Types

* Vitamin D-related rickets **
Vitamin D deficiency Vitamin D deficiency or hypovitaminosis D is a vitamin D level that is below normal. It most commonly occurs in people when they have inadequate exposure to sunlight, particularly sunlight with adequate ultraviolet B rays (UVB). Vitamin D defic ...
** Vitamin D-dependent rickets (VDDR) *** Type 1: insufficiency in activation **** VDDR1A:
25-Hydroxyvitamin D3 1-alpha-hydroxylase 25-Hydroxyvitamin D 1-alpha-hydroxylase (VD 1A hydroxylase) also known as calcidiol 1-monooxygenase or cytochrome p450 27B1 (CYP27B1) or simply 1-alpha-hydroxylase is a cytochrome P450 enzyme that in humans is encoded by the ''CYP27B1'' gene. ...
deficiency **** VDDR1B:
CYP2R1 CYP2R1 is cytochrome P450 2R1, an enzyme which is the principal vitamin D 25-hydroxylase. In humans it is encoded by the ''CYP2R1'' gene located on chromosome 11p15.2. It is expressed in the endoplasmic reticulum in liver, where it performs the fi ...
deficiency *** Type 2: resistance to calcitriol **** VDDR2A:
calcitriol receptor The vitamin D receptor (VDR also known as the calcitriol receptor) is a member of the nuclear receptor family of transcription factors. Calcitriol (the active form of vitamin D, 1,25-(OH)2vitamin D3) binds to VDR, which then forms a heterodim ...
mutation **** VDDR2B: unknown nuclear ribonucleoprotein interfering with signal transduction *** Type 3: excessive inactivation (
CYP3A4 Cytochrome P450 3A4 (abbreviated CYP3A4) () is an important enzyme in the body, mainly found in the liver and in the intestine. It oxidizes small foreign organic molecules (xenobiotics), such as toxins or drugs, so that they can be removed from t ...
mutation, dominant) * Hypocalcemia-related rickets **
Hypocalcemia Hypocalcemia is a medical condition characterized by low calcium levels in the blood serum. The normal range of blood calcium is typically between 2.1–2.6  mmol/L (8.8–10.7 mg/dL, 4.3–5.2 mEq/L) while levels less than 2.1 mm ...
**
Chronic kidney failure Chronic kidney disease (CKD) is a type of kidney disease in which a gradual loss of kidney function occurs over a period of months to years. Initially generally no symptoms are seen, but later symptoms may include leg swelling, feeling tired, vom ...
(CKD-BMD) * Hypophosphatemia-related rickets ** Congenital *** Vitamin D-resistant rickets ***
Autosomal dominant hypophosphatemic rickets Autosomal dominant hypophosphatemic rickets (ADHR) is a rare hereditary disease in which excessive loss of phosphate in the urine leads to poorly formed bones (rickets), bone pain, and tooth abscesses. ADHR is caused by a mutation in the fibroblas ...
(ADHR) *** Autosomal recessive hypophosphatemic rickets (ARHR) **
Hypophosphatemia Hypophosphatemia is an electrolyte disorder in which there is a low level of phosphate in the blood. Symptoms may include weakness, trouble breathing, and loss of appetite. Complications may include seizures, coma, rhabdomyolysis, or softening ...
(typically secondary to malabsorption) **
Fanconi's syndrome Fanconi syndrome or Fanconi's syndrome (, ) is a syndrome of inadequate reabsorption in the proximal renal tubules of the kidney. The syndrome can be caused by various underlying congenital or acquired diseases, by toxicity (for example, from toxi ...
* Secondary to other diseases ** Tumor-induced osteomalacia ** McCune-Albright syndrome **
Epidermal nevus syndrome Epidermal nevus syndrome (also known as "Feuerstein and Mims syndrome", and "Solomon's syndrome"Freedberg, et al. (2003). ''Fitzpatrick's Dermatology in General Medicine''. (6th ed.). McGraw-Hill. .) is a rare disease that was first described in 19 ...
**
Dent's disease Dent's disease (or Dent disease) is a rare X-linked recessive inherited condition that affects the proximal renal tubules of the kidney. It is one cause of Fanconi syndrome, and is characterized by tubular proteinuria, excess calcium in the urin ...


Differential diagnosis

Osteochondrodysplasias Osteochondrodysplasia 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. Non ...
, also known as genetic bone diseases, may mimic the clinical picture of rickets in regard to the features of bone deformities. The radiologic picture and the laboratory findings of serum calcium, phosphate and alkaline phosphatase are important differentiating factors.
Blount's disease Blount's disease (or Blount disease) is a growth disorder of the tibia (shin bone) which causes the lower leg to angle inward, resembling a bowleg. It is also known as "tibia vara". Description and risk factors Blount disease is a growth disorde ...
is an important differential diagnosis because it causes knee deformities in a similar fashion to rickets namely bow legs or
genu varum Genu varum (also called bow-leggedness, bandiness, bandy-leg, and tibia vara) is a varus deformity marked by (outward) bowing at the knee, which means that the lower leg is angled inward ( medially) in relation to the thigh's axis, giving th ...
. Infants with rickets can have bone fractures. This sometimes leads to child abuse allegations. This issue appears to be more common for solely nursing infants of black mothers, in winter in temperate climates, suffering poor nutrition and no vitamin D supplementation. People with darker skin produce less vitamin D than those with lighter skin, for the same amount of sunlight.


Treatment


Diet and sunlight

Treatment involves increasing dietary intake of calcium, phosphates and vitamin D. Exposure to ultraviolet B light (most easily obtained when the sun is highest in the sky),
cod liver oil Cod liver oil is a dietary supplement derived from liver of cod fish (Gadidae). As with most fish oils, it contains the omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and also vitamin A and vitamin D. Histori ...
, halibut-liver oil, and
viosterol Ergocalciferol, also known as vitamin D2 and nonspecifically calciferol, is a type of vitamin D found in food and used as a dietary supplement. As a supplement it is used to prevent and treat vitamin D deficiency. This includes vitamin D defic ...
are all sources of vitamin D. A sufficient amount of ultraviolet B light in sunlight each day and adequate supplies of calcium and phosphorus in the diet can prevent rickets. Darker-skinned people need to be exposed longer to the
ultraviolet rays Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nm (with a corresponding frequency around 30  PHz) to 400 nm (750  THz), shorter than that of visible light, but longer than X-rays. UV radiation i ...
. The replacement of vitamin D has been proven to correct rickets using these methods of ultraviolet light therapy and medicine. Recommendations are for 400
international unit In pharmacology, the international unit (IU) is a unit of measurement for the effect, not mass of a substance; the variance is based on the biological activity or effect, for the purpose of easier comparison across similar ''forms'' of substan ...
s (IU) of vitamin D a day for infants and children. Children who do not get adequate amounts of vitamin D are at increased risk of rickets. Vitamin D is essential for allowing the body to uptake calcium for use in proper bone calcification and maintenance.


Supplementation

Sufficient vitamin D levels can also be achieved through dietary supplementation and/or exposure to sunlight. Vitamin D3 (
cholecalciferol Cholecalciferol, also known as vitamin D3 and colecalciferol, is a type of vitamin D that is made by the skin when exposed to sunlight; it is found in some foods and can be taken as a dietary supplement. Cholecalciferol is made in the skin f ...
) is the preferred form since it is more readily absorbed than vitamin D2. Most
dermatologists Dermatology is the branch of medicine dealing with the skin.''Random House Webster's Unabridged Dictionary.'' Random House, Inc. 2001. Page 537. . It is a speciality with both medical and surgical aspects. A dermatologist is a specialist medical ...
recommend vitamin D supplementation as an alternative to unprotected ultraviolet exposure due to the increased risk of
skin cancer Skin cancers are cancers that arise from the skin. They are due to the development of abnormal cells that have the ability to invade or spread to other parts of the body. There are three main types of skin cancers: basal-cell skin cancer (BCC) ...
associated with sun exposure. Endogenous production with full body exposure to sunlight is approximately 250 µg (10,000 IU) per day. According to the
American Academy of Pediatrics The American Academy of Pediatrics (AAP) is an American professional association of pediatricians, headquartered in Itasca, Illinois. It maintains its Department of Federal Affairs office in Washington, D.C. Background The Academy was founded ...
(AAP), all infants, including those who are exclusively breast-fed, may need vitamin D supplementation until they start drinking at least of vitamin D-fortified milk or formula a day. Despite this recommendation, a recent Cochrane
systematic review A systematic review is a Literature review, scholarly synthesis of the evidence on a clearly presented topic using critical methods to identify, define and assess research on the topic. A systematic review extracts and interprets data from publ ...
has found limited evidence that vitamin D plus calcium, or
calcium Calcium is a chemical element with the symbol Ca and atomic number 20. As an alkaline earth metal, calcium is a reactive metal that forms a dark oxide-nitride layer when exposed to air. Its physical and chemical properties are most similar to ...
alone compared to vitamin D improves healing in children with nutritional rickets.


Surgery

Occasionally surgery is needed to correct severe and persistent deformities of the lower limbs, especially around the knees namely
genu varum Genu varum (also called bow-leggedness, bandiness, bandy-leg, and tibia vara) is a varus deformity marked by (outward) bowing at the knee, which means that the lower leg is angled inward ( medially) in relation to the thigh's axis, giving th ...
and
genu valgum Genu, a Latin word for "knee," may refer to: * Genu of internal capsule * Genu of the corpus callosum * Genu recurvatum * Genu valgum * Genu varum Genu varum (also called bow-leggedness, bandiness, bandy-leg, and tibia vara) is a varus def ...
. Surgical correction of rachitic deformities can be achieved through osteotomies or guided growth surgery. Guided growth surgery has almost replaced the use of corrective osteotomies. The functional results of guided growth surgery in children with rickets are satisfactory. While bone osteotomies work through acute/immediate correction of the limb deformity, guided growth works through gradual correction.


Epidemiology

In developed countries, rickets is a
rare disease A rare disease is any disease that affects a small percentage of the population. In some parts of the world, an orphan disease is a rare disease whose rarity means there is a lack of a market large enough to gain support and resources for discov ...
(incidence of less than 1 in 200,000). Recently, cases of rickets have been reported among children who are not fed enough vitamin D. In 2013/2014 there were fewer than 700 cases in England. In 2019 the number of cases hospitalised was said to be the highest in 50 years. Rickets occurs relatively commonly in the
Middle East The Middle East ( ar, الشرق الأوسط, ISO 233: ) is a geopolitical region commonly encompassing Arabian Peninsula, Arabia (including the Arabian Peninsula and Bahrain), Anatolia, Asia Minor (Asian part of Turkey except Hatay Pro ...
, Africa, and Asia.


History

Greek physician
Soranus of Ephesus Soranus of Ephesus ( grc-gre, Σωρανός ὁ Ἑφέσιος; 1st/2nd century AD) was a Greek physician. He was born in Ephesus but practiced in Alexandria and subsequently in Rome, and was one of the chief representatives of the Methodic ...
, one of the chief representatives of the
Methodic school The Methodic school of medicine (''Methodics'', ''Methodists'', or ''Methodici'', el, Μεθοδικοί) was a school of medicine in ancient Greece and Rome. The Methodic school arose in reaction to both the Empiric school and the Dogmatic sch ...
of medicine who practiced in
Alexandria Alexandria ( or ; ar, ٱلْإِسْكَنْدَرِيَّةُ ; grc-gre, Αλεξάνδρεια, Alexándria) is the second largest city in Egypt, and the largest city on the Mediterranean coast. Founded in by Alexander the Great, Alexandria ...
and subsequently in
Rome , established_title = Founded , established_date = 753 BC , founder = King Romulus (legendary) , image_map = Map of comune of Rome (metropolitan city of Capital Rome, region Lazio, Italy).svg , map_caption ...
, reported deformation of the bones in infants as early as the first and second centuries AD. Rickets was not defined as a specific medical condition until 1645, when an English physician Daniel Whistler gave the earliest known description of the disease. In 1650 a treatise on rickets was published by
Francis Glisson Francis Glisson (1597 – 14 October 1677Guido Giglioni'Glisson, Francis (1599?–1677)' ''Oxford Dictionary of National Biography'', Oxford University Press, Sept 2004; online edn, May 2006, accessed 31 December 2008) was a British physicia ...
, a physician at
Caius College, Cambridge Gonville and Caius College, often referred to simply as Caius ( ), is a constituent college of the University of Cambridge in Cambridge, England. Founded in 1348, it is the fourth-oldest of the University of Cambridge's 31 colleges and one of th ...
, who said it had first appeared about 30 years previously in the counties of
Dorset Dorset ( ; archaically: Dorsetshire , ) is a county in South West England on the English Channel coast. The ceremonial county comprises the unitary authority areas of Bournemouth, Christchurch and Poole and Dorset (unitary authority), Dors ...
and
Somerset ( en, All The People of Somerset) , locator_map = , coordinates = , region = South West England , established_date = Ancient , established_by = , preceded_by = , origin = , lord_lieutenant_office =Lord Lieutenant of Somerset , lord_ ...
. In 1857, John Snow suggested rickets, then widespread in Britain, was being caused by the adulteration of bakers' bread with
alum An alum () is a type of chemical compound, usually a hydrated double salt, double sulfate salt (chemistry), salt of aluminium with the general chemical formula, formula , where is a valence (chemistry), monovalent cation such as potassium or a ...
. German pediatrician
Kurt Huldschinsky Kurt Huldschinsky (1883 in Berlin – 31 October 1940, in Alexandria) was a German pediatrician of Prussian heritage. He completed his medical studies prior to serving in the Deutsches Heer as a field medic in World War I and later, after the Grea ...
successfully demonstrated in the winter of 1918–1919 how rickets could be treated with
ultraviolet Ultraviolet (UV) is a form of electromagnetic radiation with wavelength from 10 nanometer, nm (with a corresponding frequency around 30 Hertz, PHz) to 400 nm (750 Hertz, THz), shorter than that of visible light, but longer than ...
lamps. The role of diet in the development of rickets was determined by
Edward Mellanby Sir Edward Mellanby (8 April 1884 – 30 January 1955) was a British biochemist and nutritionist who discovered vitamin D and its role in preventing rickets in 1919. Education Mellanby was born in West Hartlepool, the son of a shipyard owner, ...
between 1918 and 1920. In 1923, American physician
Harry Steenbock Harry Steenbock (August 16, 1886, Charlestown, Wisconsin – December 25, 1967, Madison, Wisconsin) was a Professor of Biochemistry at the University of Wisconsin–Madison. Steenbock graduated from Wisconsin in 1916, where he was a member o ...
demonstrated that irradiation by ultraviolet light increased the vitamin D content of foods and other organic materials. Steenbock's irradiation technique was used for foodstuffs, but most memorably for milk. By 1945, rickets had all but been eliminated in the United States.


Etymology

The word ''rickets'' may be from the
Old English Old English (, ), or Anglo-Saxon, is the earliest recorded form of the English language, spoken in England and southern and eastern Scotland in the early Middle Ages. It was brought to Great Britain by Anglo-Saxon settlement of Britain, Anglo ...
word ('to twist'), although because this is conjectured, several major dictionaries simply say "origin unknown". The name ''rickets'' is plural in form but usually singular in construction. The Greek word (, meaning 'in or of the spine') was later adopted as the scientific term for rickets, due chiefly to the words' similarity in sound. ''Vide'': Aubrey's Brief Lives: the word has no connection whatever with the Greek ''rachitis''. I quote: " about 1620 one Ricketts of Newberye a Practictioner of Physick was excellent at the Curing Children with swoln heads, and small legges: and the Disease being new, and without a name, He being so famous for the cure of it, they called the Disease the Ricketts: as the King's Evill from the King's cureing of it with his Touch; and now 'tis good sport to see how they vex their Lexicons, and fetch it from the Greek PaXis, the back bone."


See also

*
Hypervitaminosis D Vitamin D toxicity, or hypervitaminosis D is the toxic state of an excess of vitamin D. The normal range for blood concentration is 20 to 50 nanograms per milliliter (ng/mL). However, the toxic state is known to be a value of 100 ng/ml or more in ...


References


External links

* {{Authority control Skeletal disorders Vitamin D Vitamin deficiencies Wikipedia medicine articles ready to translate