Presentation on theme: "Lecturer: prof. Pavlyshyn G.A. Rickets: Etiology, pathogenesis, clinical features, diagnostics, treatment and prevention."— Presentation transcript:
Lecturer: prof. Pavlyshyn G.A. Rickets: Etiology, pathogenesis, clinical features, diagnostics, treatment and prevention
Rickets is a childhood disorder involving softening and weakening of the bones. It is primarily caused by lack of vitamin D, calcium, or phosphate.
Vitamin D is a fat-soluble vitamin that may be absorbed from the intestines or may be produced by the skin when the skin is exposed to sunlight (ultraviolet light of sunlight helps the body to form vitamin D). The absorbed vitamin D is converted into its active form to act as a hormone to regulate calcium absorption from the intestine and to regulate levels of calcium and phosphate in the bones. If there is a deficiency of Vitamin D, the body is unable to properly regulate calcium and phosphate levels. When the blood levels of these minerals become too low, it results in destruction of the support matrix of the bones.
Sunlight as a source of vitamin D Lack of vitamin D production by the skin may occur if a person is confined indoors, or works indoors during the daylight hours, or lives in climates with little exposure to sunlight. Sunlight is important to skin production of vitamin D and environmental conditions where sunlight exposure is limited may reduce this source of vitamin D.
Sunlight as a source of vitamin D Adequate supplies of vitamin D 3 can be synthesized with sufficient exposure to solar ultraviolet B radiation Melanin, clothing or sunscreens that absorb UVB will reduce cutaneous production of vitamin D 3
Rickets In rickets, another mechanism in the body works to increase the blood calcium level. The parathyroid gland may increase its functioning rate to compensate for decreased levels of calcium in the bloodstream. To increase the level of calcium in the blood the hormone destroys the calcium present in the bones of the body and this results in further loss of calcium and phosphorous from the bones. In severe cases, cysts may develop in the bones. Vitamin D deficiency could be caused due to numerous reasons
What are the causes for deficiency of Vitamin D?
Reasons of vitamin D deficiency Environmental conditions where sunlight exposure is limited like indoor confinement or working indoors during daylight hours may reduce source of vitamin D; Inadequate daily consumption - a lack of vitamin D in the diet, a dietary lack of calcium and phosphorous may also play a part in nutritional causes of rickets, have trouble digesting milk products, people who are lactose intolerant; Liver Failure; Dark Pigmentation
Reasons of deficiency vitamin D Problem of malabsorption called steatorrhea, in which the body is unable to absorb fats, and they are passed directly out the body in the stool. The result of this problem is that Vitamin D, which is usually absorbed with fat, and calcium are poorly absorbed. This poor absorption can be a result of digestive disorders. Steatorrhea could also lead to other deficiencies. Kidney Failure (congenital or acquired kidney disorders) - due to tubular acidosis in which there is an increased amount of acid in the body;
Etiology 1. Lack of sunshine due to: 1) Lack of outdoor activities 2) Lack of ultraviolet light in fall and winter 3) Too much cloud, dust, vapour and smoke
Etiology 2. Improper feeding: 1) Inadequate intake of Vitamin D Breast milk 0-10IU/100ml Cow’s milk 0.3-4IU/100ml Egg yolk 25IU/average yolk Herring 1500IU/100g 2) Improper Ca and P ratio
Cholecalciferol (vitamin D-3) is formed in the skin from 7-dihydrotachysterol. This steroid undergoes hydroxylation in 2 steps. Pathophysiology - Metabolism of vitamin D The first hydroxylation occurs at position 25 in the liver, producing calcidiol (25-hydroxycholecalciferol), which circulates in the plasma as the most abundant of the vitamin D metabolites and is thought to be a good indicator of overall vitamin D status.
Cholecalciferol (vitamin D-3) is formed in the skin from 7-dihydrotachysterol. This steroid undergoes hydroxylation in 2 steps. Pathophysiology The second hydroxylation step occurs in the kidney at the 1 position, where it undergoes hydroxylation to the active metabolite calcitriol (1,25-dihydroxycholecalciferol - DHC). This cholecalciferol is not a vitamin, but a hormone.
Vitamin D: The Sunshine Vitamin Not always essential –Body can make it if exposed to enough sunlight –Made from cholesterol in the skin
Pathway of Vitamin D Production
Calcitriol acts on regulation of calcium metabolism : Calcitriol promotes absorption of calcium and phosphorus from the intestine, increases reabsorption of phosphate in the kidney, acts on bone to release calcium and phosphate; Calcitriol may also directly facilitate calcification. Calcitriol (1,25-DHC) – acts as a hormone rather than a vitamin, endocrine and paracrine properties
These actions increase the concentrations of calcium and phosphorus in extracellular fluid. The increase of Ca and P in extracellular fluid, in turn, leads to the calcification of osteoid, primarily at the metaphyseal growing ends of bones but also throughout all osteoid in the skeleton. Parathyroid hormone facilitates the 1-hydro- xylation step in vitamin D metabolism
Pathogenesis Vitamin D deficiency Absorption of Ca, P Serum Ca Function of Parathyroid
Pathogenesis PTH High secretion P in urine Decalcification of old bone P in blood Ca in blood normal or low slightly Ca, P product Rickets
Pathogenesis Low secretion of PTH Failure of decalcification of bone Low serum Ca level Rachitic tetany (Spasmophylia)
In the vitamin D deficiency state, hypocalciemia develops, which stimulates excess parathyroid hormone, which stimulates renal phosphorus loss, further reducing deposition of calcium in the bone. Excess parathyroid hormone also produces changes in the bone similar to those occurring in hyperparathyroidism.
Early in the course of rickets, the calcium concentration in the serum decreases. After the parathyroid response, the calcium concentration usually returns to the reference range, though phosphorus levels remain low. Alkaline phosphatase, which is produced by overactive osteoblast cells, leaks to the extracellular fluids so that its concentration rises to anywhere from moderate elevation to very high levels.
The history in patients with rickets may include the following: The infant's gestational age, diet and degree of sunlight exposure should be noted. A detailed dietary history should include specifics of vitamin D and calcium intake. A family history of short stature, orthopedic abnormalities, poor dentition, alopecia, parental consanguinity may signify inherited rickets. Evaluation
Clinical signs Rickets is a systematic disease with skeletons involved most, but the nervous system, muscular system and other system are also involved.
Generalized muscular hypotonia is observed in the most patients with clinical signs of rickets. Craniotabes manifests early in infants, although this feature may be normal in infants, especially for those born prematurely. Clinical signs If rickets occurs at a later age, thickening of the skull develops. This produces frontal bossing and delays the closure of the anterior fontanelle. Frontal bossing
Protruding forehead asymmetrical or odd-shaped skull
Skeletal deformities including Bow legs, Forward projection of the breastbone - pigeon chest or pectus carinatum), Funnel chest (pectus excavatum), "Bumps" in the rib cage (rachitic rosary) and asymmetrical or odd-shaped skull;
Clinical signs In the chest, knobby deformities results in the rachitic rosary along the costochondral junctions. The weakened ribs pulled by muscles also produce flaring over the diaphragm, which is known as Harrison groove. The sternum may be pulled into a pigeon- breast deformity. Rib beading (rachitic rosary )
A teenage male with rickets. Note deformities of legs (bow legs) and compromised height.
The ends of the long bones demonstrate that same knobby thickening. At the ankle, palpation of the tibial Clinical signs malleolus gives the impression of a double epiphysis (Marfan sign).
Clinical signs Increased tendency toward bone fractures. Because the softened long bones may bend, they may fracture one side of the cortex (greenstick fracture). In the long bones, laying down of uncalcified osteoid at the metaphases leads to spreading of those areas, producing knobby deformity (cupping and flaring of the metaphyses).
Spine deformities (spine curves abnormally, including scoliosis or kyphosis). In more severe instances in children older than 2 years, vertebral softening leads to kyphoscoliosis Clinical signs
Pain in the bones of Arms, Legs, Spine, Pelvis. Dental deformities Delayed formation of teeth Defects in the structure of teeth Holes in the enamel Increased incidence of cavities in the teeth (dental caries) Clinical signs
Progressive weakness Decreased muscle tone (loss of muscle strength) Muscle cramps Impaired growth Short stature (adults less than 5 feet tall) Fever or restlessness, especially at night Clinical signs
Bowlegs and knock-knees Short stature
In children with rickets, complete physical and dental examinations should be performed. The entire skeletal system must be palpated to search for tenderness and bony abnormalities. Rickets should be suspected in older bowlegged children and in cases associated with asymmetry, pain, or progression in severity. Physical examination
Gait disturbances and neurologic abnormalities (such as hyperreflexia) in all children should be sought. The review of systems should focus on growth and orthopedic concerns and signs and symptoms of hypocalcemia, such as muscle cramps, numbness, paresthesias, tetany and seizures.
Laboratory findings Laboratory investigation may include: serum levels of calcium (total and ionized with serum albumin), phosphorus, alkaline phosphatase ( ALP) parathyroid hormone, urea nitrogen, calcidiol urine studies include urinalysis and levels of urinary calcium and phosphorus.
Decreases in serum calcium, serum phosphorus, calcidiol, calcitriol, urinary calcium. The most common laboratory findings in nutritional rickets are: Parathyroid hormone, alkaline phosphatase, urinary phosphorus levels are elevated.
Early on in the course of rickets, the calcium (ionized fraction) is low; however it is often within the reference range at the time of diagnosis as parathyroid hormone levels increase. Calcidiol (25-hydroxy vitamin D) levels are low, and parathyroid hormone levels are elevated; however, determining calcidiol and parathyroid hormone levels is typically not necessary. Calcitriol levels may be normal or elevated because of increased parathyroid activity. The phosphorus level is invariably low for age. Alkaline phospohatase levels are elevated. A generalized aminoaciduria occurs from the parathyroid activity; aminoaciduria does not occur in familial hypophosphatemia rickets (FHR). Laboratory Studies
Classic radiographic findings include: widening of the distal epyphysis, fraying and widening of the metaphysis, and angular deformities of the arm and leg bones.
Classic radiographic findings include Anteroposterior and lateral radiographs of the wrist of an 8-year- old boy with rickets demonstrates cupping and fraying of the metaphyseal region
Classic radiographic findings include: Radiographs of the knee of a 3-year-old girl with hypophosphatemia depict severe fraying of the metaphysis.
Rickets in wrist - uncalcified lower ends of bones are porous, ragged, and saucer-shaped (A) Rickets in 3 month old infant (B) Healing after 28 days of treatment (C) After 41 days of treatment A BC
Radiographic image of wrist and forearm showing pathologic fractures of radius and ulna with rachitic changes of distal end of radius and ulna.
X-ray in rickets
Clinical manifestation Stages Early stage Usually begin at 3 months old Symptoms: mental psychiatric symptoms Irritability, sleepless, hidrosis Signs: occipital bald Laboratory findings: Serum Ca, P normal or decreased slightly, AKP normal or elevated slightly, 25(OH)D3 decreased Roentgen-graphic changes: normal or slightly changed
Clinical manifestation Advanced stage On the base of early rickets, osseous changes become marked and motor development becomes delayed. 1. Osseous changes: 1) Head: craniotabes, frontal bossing, boxlike appearance of skull, delayed closure of anterior fontanelle 2) Teeth: delayed dentition with abnormal order, defects 3) Chest: rachitic rosary, Harrison’s groove, pigeon chest, funnel-shaped chest, flaring of ribs
Clinical manifestation 4) Spinal column: scoliosis, kyphosis, lordosis 5) Extremities: bowlegs, knock knee, greenstick fracture 6) Rachitic dwarfism 2. Muscular system: potbelly, late in standing and walking 3. Motor development: delayed 4. Other nervous and mental symptoms
Clinical manifestation Laboratory findings: Serum Ca and P decreased Ca and P product decreased AKP elevated Roentgen-graphic changes: Wrist is the best site for watching the changes Widening of the epiphyseal cartilage Blurring of the cup-shape metaphyses of long bone
Clinical manifestation Healing stage: Symptoms and signs of Rickets alleviate or disappear by use of appropriate treatment. The blood chemistries become normal, except AKP, that may be slightly elevated. Sequelae stage: All the clinical symptoms and signs disappear. Blood Chemistries and X-ray changes are recovered, but osseous deformities may be left. Usually seen in Children after 3 years old.
I Mild form: small changes of nervous system, changes of one part of the skeleton; II Moderate form: changes of all organs and systems, changes of two parts of the skeleton; III Severe form: damaging function of all organs and systems, changes of three parts of the skeleton; Classification
Types of Rickets Nutritional Nutritional rickets results from inadequate sunlight exposure or inadequate intake of dietary vitamin D, calcium, or phosphorus.
Vitamin D dependent Vitamin D-dependent rickets, type I is secondary to a defect in the gene that codes for the production of renal 25(OH)D3-1-alpha-hydroxylase. Vitamin D-dependent rickets, type II is a rare autosomal disorder caused by mutations in the vitamin D receptor. Type II does not respond to vitamin D treatment; elevated levels of circulating calcitriol differentiate this type from type I.
Vitamin D resistant Rickets refractory to vitamin D treatment may be caused by the most common heritable form, known as vitamin D-resistant rickets or familial hypophosphatemic rickets. Because of mutations of the phosphate-regulating gene on the X chromosome, renal wasting of phosphorus at the proximal tubule level results in hypophosphatemia. Normal levels of calcitriol are found in this disorder.
Other Conditions That Can Cause Rickets Medications –Antacids –Anticonvulsants –Corticosteroids –Loop diuretics Malignancy Prematurity Diseases of organs associated with vitamin D and calcium metabolism –Kidney disease –Liver and biliary tract disease Malabsorption syndromes –Celiac disease –Cystic fibrosis (rare)
Diagnosis Assessed according to the followings: 1. History 2. Physical examination 3. Laboratory findings 4. Roentgen-graphic changes
What's the treatment for rickets? The replacement of Vitamin D may correct rickets using these methods of ultraviolet light and medicine. Rickets heals promptly with 4000 IU of oral vitamin D per day administered for approximately one month. Parents are instructed to take their infants outdoors for approximately 20 minutes per day with their faces exposed. Children should also be encouraged to play outside. Foods that are good sources of vitamin D include cod liver oil, egg yolks, butter and oily fish. Some foods, including milk and breakfast cereals, are also fortified with synthetic vitamin D.
Treatment 1.Special therapy: Vitamin D therapy A. General method: Vitamin D IU/day for 2-4 weeks, then change to preventive dosage – 400 IU. B. A single large dose: For severe case, or Rickets with complication, or those who can’t bear oral therapy. Vitamin D – IU, im, preventive dosage will be used after 2-3 months.
TREATMENT 1 STAGE VITAMINE D – “VIDEIN – 3” IU 1 TIME\DAY 30 DAYS 2 STAGE VITAMINE D – “VIDEIN – 3” IU 1 TIME\DAY 40 DAYS 3 STAGE VITAMINE D – “VIDEIN – 3” IU 1 TIME\DAY 45 DAYS Then profilactic dose – 500 iu till the end of the second – third year of life
Vitamin D Fat-soluble vitamin used to treat vitamin D deficiency or for prophylaxis of deficiency. Cholecalciferol (Delta-D) Vitamin D-3 1 mg provides IU vitamin D activity
Treatment 4. Calcium supplementation: Dosage: 1-3 g/day only used for special cases, such as baby fed mainly with cereal or infants under 3 months of age and those who have already developed tetany. 5. Plastic therapy: In children with bone deformities after 4 years old plastic surgery may be useful.
Prevention 1. Pay much attention to the health care of pregnant and lactating women, instruct them to take adequate amount of vitamin D. 2. Advocate sunbathing 3. Advocate breast feeding, give supplementary food on time
Prevention Vitamin D supplements Because of human milk contains only a small amount of vitamin D, the American Academy of Pediatrics (AAP) recommends that all breast-fed infants receive 400 IU of oral vitamin D daily beginning during the first two months of life and continuing until the daily consumption of vitamin D-fortified formula or milk is two to three glasses, or 500 mL. AAP also recommends that all children and adolescents should receive 400 IU a day of vitamin D.
Prevention Vitamin D supplementation: In prematures, twins and weak babies, give Vitamin D 800IU per day, For term babies and infants the demand of Vitamin D is 400IU per day, For those babies who can’t maintain a daily supplementation, inject muscularly Vitamin D IU.
Prevention Calcium supplementation: 0.5-1gm/day, for premature, weak babies and babies fed mainly with cereal Recommended daily intake of calcium is as follows: 1 to 3 years of age. 500 mg (two servings of dairy products a day) 4 to 8 years of age. 800 mg (two to three servings of dairy products a day) 9 to 18 years of age. 1,300 mg (four servings of dairy products a day) 19 to 50 years of age. 1,000 mg a day (three servings of dairy products a day)
Sources of Vitamin D Sunlight is the most important source Fish liver oil Fish & sea food (herring & salmon) Eggs Plants do not contain vitamin D3
Fast foods Cheeseburger20 Chicken nuggets (four to six pieces) 13 French fries (small order)10 Pizza (one slice)145 Greens Cabbage (collard) (1/2 cup, cooked) 150 Spinach (1 cup, cooked)150
Spasmophylia (children's tetany) disease, in the basis of which disturbances of mineral metabolism (decrease of concentration of ionized calcium in a blood) lies. It is characterized increased nervous-muscle exiting and predilection to tonic and clonic cramps of separate groups of muscles, in particular larynxes, legs and arms. Etiology: hypovitaminosis D, hypoparathyreoidis
Latent form By a sign Hvostek — simple tapping the cheek over the facial nerve causes involuntary contraction of the muscles about the eye or mouth (spasm of facial muscles occurs when the facial nerve is tapped) By Trousseau's Sign — is the carpal or pedal spasm, induced by compression of the arm or thigh during 3-5 minutes (by the cuff for measurement of arterial pressure) when hands assume the so- called “obstetrical position”, while the feet are held in a position of equinas; By a sign Maslow — stop of breathing at a mild skin pricks By a sign Еrba — increased reaction to electrical stimulation of the median or peroneal nerve (by a galvanic current smaller than 5 mа)
The manifestive form The three most characteristic symptoms are: 1. Laryngo-spasm or laryngismus stridulus; 2. Tetany or carpo-pedal spasm; 3. Eclampsia, or general convulsions.
Treatment I. First aid. At a laryngospasm - to clap on cheeks, to wash by cold water; At cramps - Seduxen (0,5 % solution, 0,1 mg/kg), simultaneously a calcium drug - 20 mg/kg elemental calcium IV over minutes Equal to: 2 mL/kg 10% calcium gluconate 0.7 mL/kg 10% calcium chloride ІІ. Correction of a feed (limitation of the cow milk, increase vegetables and fruits). Drugs of calcium (10 % solution of calcium of a gluconate at the rate of 50mg/kg/day). After normalization of a level of calcium in a blood - treatment by vitamin D3 ( МО days depending on a degree of gravity of a rickets).
What are the signs and symptoms associated with hypervitaminosis of Vit. D.
TOXICITY Hypervitaminosis DHypervitaminosis D causes hypercalcemia, which manifest as: Nausea & vomiting Excessive thirst & polyuria Severe itching Joint & muscle pains Disorientation & coma.
Vitamin D Toxicity Calcification of soft tissue –Lungs, heart, blood vessels –Hardening of arteries (calcification) Hypercalcemia –Normal is ~ 10 mg/dl –Excess blood calcium leads to stone formation in kidneys Lack of appetite