Rickets
Overview
 
Rickets is a softening of bones in children due to deficiency or impaired metabolism of vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....

, magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

 , phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

 or calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

, potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries. The predominant cause is a vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....

 deficiency, but lack of adequate calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

 in the diet may also lead to rickets (cases of severe diarrhea and vomiting may be the cause of the deficiency).
Encyclopedia
Rickets is a softening of bones in children due to deficiency or impaired metabolism of vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....

, magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...

 , phosphorus
Phosphorus
Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

 or calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

, potentially leading to fractures and deformity. Rickets is among the most frequent childhood diseases in many developing countries. The predominant cause is a vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....

 deficiency, but lack of adequate calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

 in the diet may also lead to rickets (cases of severe diarrhea and vomiting may be the cause of the deficiency). Although it can occur in adults, the majority of cases occur in children suffering from severe malnutrition
Malnutrition
Malnutrition is the condition that results from taking an unbalanced diet in which certain nutrients are lacking, in excess , or in the wrong proportions....

, usually resulting from famine
Famine
A famine is a widespread scarcity of food, caused by several factors including crop failure, overpopulation, or government policies. This phenomenon is usually accompanied or followed by regional malnutrition, starvation, epidemic, and increased mortality. Every continent in the world has...

 or starvation
Starvation
Starvation is a severe deficiency in caloric energy, nutrient and vitamin intake. It is the most extreme form of malnutrition. In humans, prolonged starvation can cause permanent organ damage and eventually, death...

 during the early stages of childhood.
Osteomalacia
Osteomalacia
Osteomalacia is the softening of the bones caused by defective bone mineralization secondary to inadequate amounts of available phosphorus and calcium, or because of overactive resorption of calcium from the bone as a result of hyperparathyroidism...

 is the term used to describe a similar condition occurring in adults, generally due to a deficiency of vitamin D
Vitamin D
Vitamin D is a group of fat-soluble secosteroids. In humans, vitamin D is unique both because it functions as a prohormone and because the body can synthesize it when sun exposure is adequate ....

. The origin of the word "rickets" is probably from the Old English dialect word 'wrickken', to twist. The Greek derived word "rachitis" (ραχίτις, meaning "inflammation of the spine") was later adopted as the scientific term for rickets, due chiefly to the words' similarity in sound.
Signs and symptoms
Signs and symptoms of rickets include:
  • Bone pain or tenderness
  • dental
    Tooth
    Teeth are small, calcified, whitish structures found in the jaws of many vertebrates that are used to break down food. Some animals, particularly carnivores, also use teeth for hunting or for defensive purposes. The roots of teeth are embedded in the Mandible bone or the Maxillary bone and are...

     problems
  • muscle
    Muscle
    Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...

     weakness (rickety myopathy or "floppy baby syndrome" or "slinky baby" (such that the baby is floppy or slinky-like)
  • increased tendency for fracture
    Fracture
    A fracture is the separation of an object or material into two, or more, pieces under the action of stress.The word fracture is often applied to bones of living creatures , or to crystals or crystalline materials, such as gemstones or metal...

    s (easily broken bones), especially greenstick fracture
    Greenstick fracture
    A greenstick, buckle or torus fracture is a fracture in a young, soft bone in which the bone bends and partially breaks. A person's bones become harder and more brittle with age. Greenstick fractures usually occur most often during infancy and childhood when bones are soft...

    s
  • Skeletal deformity
    • Toddlers: Bowed legs (genu varum)
    • Older children: Knock-knees (genu valgum
      Genu valgum
      Genu valgum, commonly called "knock-knee", is a condition where the knees angle in and touch one another when the legs are straightened. Women have a wider pelvis than men and a relatively shorter length of the thigh bone, and as a result, have a greater static genu valgum than men...

      ) or "windswept knees"
    • Cranial, pelvic, and spinal deformities (such as lumbar lordosis
      Lordosis
      Lordosis is a medical term used to describe an inward curvature of a portion of the lumbar and cervical vertebral column. Two segments of the vertebral column, namely cervical and lumbar, are normally lordotic, that is, they are set in a curve that has its convexity anteriorly and concavity...

      )
  • Growth disturbance


  • Hypocalcemia (low level of calcium in the blood)
  • Tetany
    Tetany (medical sign)
    Tetany is a medical sign consisting of the involuntary contraction of muscles, which may be caused by disease or other conditions that increase the action potential frequency...

     (uncontrolled muscle spasms all over the body)
  • Craniotabes
    Craniotabes
    Craniotabes is an abnormal softening or thinning of the skull, although normally present in newborns. Seen mostly in occipital bone and posterior part of parietal bone. Bone is soft and has a ping pong ball like feeling on pressing. The term is derived from the Latin words cranium for skull and...

     (soft skull)
  • Costochondral
    Costochondral joint
    The costochondral joints are the articulations between the ribs and costal cartilage. They are hyaline cartilagenous joints. Each rib has a depression shaped like a cup that the costal cartilage articulates with. There is normally no movement at these joints. Joints between costal cartilages of...

     swelling (aka "rickety rosary" or "rachitic rosary
    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 beads of a rosary.- Pathophysiology :Rachitic rosary...

    ")
  • Harrison's groove
    Harrison's groove
    Harrison's groove, also known as Harrison's sulcus, is a horizontal line at the lower margin of the thorax where the diaphragm attaches to the ribs.It is usually caused by chronic asthma or obstructive respiratory disease...

  • Double malleoli sign due to metaphyseal hyperplasia
  • Widening of wrist raises early suspicion, it is due to metaphysial cartilage hyperplasia.

An X-ray
X-ray
X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

 or radiograph
Radiography
Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition....

 of an advanced sufferer from rickets tends to present in a classic way: bow 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. These deformities persist into adult life if not treated. Long-term consequences include permanent bends or disfiguration of the long bones, and a curved back
Scoliosis
Scoliosis is a medical condition in which a person's spine is curved from side to side. Although it is a complex three-dimensional deformity, on an X-ray, viewed from the rear, the spine of an individual with scoliosis may look more like an "S" or a "C" than a straight line...

.

Types

  • Nutritional Rickets
  • Vitamin D Resistant Rickets
  • Vitamin D Dependent Rickets
    • Type I
    • Type II
  • Congenital Rickets

Cause

The primary cause of rickets is a vitamin D deficiency. Vitamin D is required for proper calcium absorption from the gut. 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
Hypocalcaemia
In medicine, hypocalcaemia is the presence of low serum calcium levels in the blood, usually taken as less than 2.1 mmol/L or 9 mg/dl or an ionized calcium level of less than 1.1 mmol/L or 4.5 mg/dL. It is a type of electrolyte disturbance...

, leading to skeletal and dental deformities and neuromuscular symptoms, e.g. hyperexcitability. Foods that contain vitamin D include butter, eggs, fish liver oils, margarine, fortified milk and juice, and oily fish
Oily fish
Oily fish have oil in their tissues and in the belly cavity around the gut. Their fillets contain up to 30 percent oil, although this figure varies both within and between species...

es such as tuna, herring, and salmon. A rare X-linked dominant
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
X-linked hypophosphatemia
X-linked hypophosphatemia , also called X-linked dominant hypophosphatemic rickets, X-linked vitamin d-resistant rickets or hypophosphatemic vitamin d-resistant rickets , is an X-linked dominant form of rickets that differs from most cases of rickets in that ingestion of vitamin D is relatively...

.

Cases have been reported in Britain in recent years of rickets in children of many social backgrounds caused by inability to make vitamin D because the sun's ultraviolet light was not reaching the skin because of persistent use of strong sunblock, or too much "covering up" in sunlight, or spending too much time indoors. 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. The British Medical Journal
British Medical Journal
BMJ is a partially open-access peer-reviewed medical journal. Originally called the British Medical Journal, the title was officially shortened to BMJ in 1988. The journal is published by the BMJ Group, a wholly owned subsidiary of the British Medical Association...

reported in 2010 that doctors in Newcastle on Tyne saw 20 cases of rickets per year.

Diagnosis

Rickets may be diagnosed with the help of:
  • Blood tests:
    • Serum calcium
      Calcium
      Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...

       may show low levels of calcium, serum phosphorus
      Phosphorus
      Phosphorus is the chemical element that has the symbol P and atomic number 15. A multivalent nonmetal of the nitrogen group, phosphorus as a mineral is almost always present in its maximally oxidized state, as inorganic phosphate rocks...

       may be low, and serum alkaline phosphatase
      Alkaline phosphatase
      Alkaline phosphatase is a hydrolase enzyme responsible for removing phosphate groups from many types of molecules, including nucleotides, proteins, and alkaloids. The process of removing the phosphate group is called dephosphorylation...

       may be high.
  • Arterial blood gas
    Arterial blood gas
    An arterial blood gas is a blood test that is performed using blood from an artery. It involves puncturing an artery with a thin needle and syringe and drawing a small volume of blood. The most common puncture site is the radial artery at the wrist, but sometimes the femoral artery in the groin or...

    es may reveal metabolic acidosis
    Metabolic acidosis
    In medicine, metabolic acidosis is a condition that occurs when the body produces too much acid or when the kidneys are not removing enough acid from the body. If unchecked, metabolic acidosis leads to acidemia, i.e., blood pH is low due to increased production of hydrogen by the body or the...

  • X-ray
    X-ray
    X-radiation is a form of electromagnetic radiation. X-rays have a wavelength in the range of 0.01 to 10 nanometers, corresponding to frequencies in the range 30 petahertz to 30 exahertz and energies in the range 120 eV to 120 keV. They are shorter in wavelength than UV rays and longer than gamma...

    s of affected bones may show loss of calcium from bones or changes in the shape or structure of the bones.
  • Bone biopsy is rarely performed but will confirm rickets.

Diet and sunlight

Treatment involves increasing dietary intake of calcium, phosphates and vitamin D. Exposure to ultraviolet B light (sunshine when the sun is highest in the sky), cod liver oil
Cod liver oil
Cod liver oil is a nutritional supplement derived from liver of cod fish. It has high levels of the omega-3 fatty acids, EPA and DHA, and very high levels of vitamin A and vitamin D. It is widely taken to ease the symptoms of arthritis and for other health benefits...

, halibut-liver oil, and viosterol
Ergosterol
Ergosterol is a sterol found in fungi, and named for ergot, a common name for the members of the fungal genus Claviceps from which ergosterol was first isolated. Ergosterol does not occur in plant or animal cells...

 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 babies need to be exposed longer to the ultraviolet rays
Ultraviolet
Ultraviolet light is electromagnetic radiation with a wavelength shorter than that of visible light, but longer than X-rays, in the range 10 nm to 400 nm, and energies from 3 eV to 124 eV...

. 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
International unit
In pharmacology, the International Unit is a unit of measurement for the amount of a substance, based on biological activity or effect. It is abbreviated as IU, as UI , or as IE...

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
Cholecalciferol is a form of vitamin D, also called vitamin D3 or calciol.It is structurally similar to steroids such as testosterone, cholesterol, and cortisol .-Forms:Vitamin D3 has several forms:...

) is the preferred form since it is more readily absorbed than vitamin D2. Most dermatologists
Dermatology
Dermatology is the branch of medicine dealing with the skin and its diseases, a unique specialty with both medical and surgical aspects. A dermatologist takes care of diseases, in the widest sense, and some cosmetic problems of the skin, scalp, hair, and nails....

 recommend vitamin D supplementation as an alternative to unprotected ultraviolet exposure due to the increased risk of skin cancer 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
American Academy of Pediatrics
The American Academy of Pediatrics is the major professional association of pediatricians in the United States. The AAP was founded in 1930 by 35 pediatricians to address pediatric healthcare standards. It currently has 60,000 members in primary care and sub-specialist areas...

 (AAP), all infants, including those who are exclusively are breast-fed, may need Vitamin D supplementation until they start drinking at least 17 USfloz of vitamin D-fortified milk or formula a day.

Epidemiology

In developed countries, rickets is a rare disease
Rare disease
A rare disease, also referred to as an orphan disease, is any disease that affects a small percentage of the population.Most rare diseases are genetic, and thus are present throughout the person's entire life, even if symptoms do not immediately appear...

 (incidence of less than 1 in 200,000).

Those at higher risk for developing rickets include:
  • Breast-fed
    Breastfeeding
    Breastfeeding is the feeding of an infant or young child with breast milk directly from female human breasts rather than from a baby bottle or other container. Babies have a sucking reflex that enables them to suck and swallow milk. It is recommended that mothers breastfeed for six months or...

     infants whose mothers are not exposed to sunlight
  • Breast-fed infants who are not exposed to sunlight
  • Babies with dark complexions (e.g. brown skin, African), particularly when breastfed and exposed to little sunlight
  • Individuals not consuming milk, such as those who are lactose intolerant
    Lactose intolerance
    Lactose intolerance, also called lactase deficiency or hypolactasia, is the inability to digest and metabolize lactose, a sugar found in milk...



Individuals with red hair
Red hair
Red hair occurs on approximately 1–2% of the human population. It occurs more frequently in people of northern or western European ancestry, and less frequently in other populations...

have been speculated to have a decreased risk for rickets due to their greater production of vitamin D in sunlight.

Children ages 6 months to 24 months are at highest risk, because their bones are rapidly growing. Long-term consequences include permanent bends or disfiguration of the long bones, and a curved back.
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