{"id":4422541,"date":"2025-01-11T23:10:53","date_gmt":"2025-01-12T05:10:53","guid":{"rendered":"https:\/\/myendoconsult.com\/learn\/topics\/rickets-and-vitamin-d-disorders\/"},"modified":"2025-01-13T06:24:56","modified_gmt":"2025-01-13T12:24:56","slug":"rickets-and-vitamin-d-disorders","status":"publish","type":"oen_topic","link":"https:\/\/myendoconsult.com\/learn\/topics\/rickets-and-vitamin-d-disorders\/","title":{"rendered":"Rickets and Vitamin D Disorders"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">NUTRITIONAL-DEFICIENCY RICKETS AND OSTEOMALACIA<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Definition &amp; Distinction<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Rickets<\/strong>: Occurs in children with deficient mineralization at the growth plate.\n<ul class=\"wp-block-list\">\n<li>Leads to widened, irregular epiphyseal plates.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Osteomalacia<\/strong>: Deficient mineralization of bone matrix in adults.\n<ul class=\"wp-block-list\">\n<li>Leads to uncalcified osteoid seams, soft bones with bowing, pseudofractures.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Key Nutrient Shortfalls<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Calcium and\/or phosphate<\/strong> deficiency.<\/li>\n\n\n\n<li>Most commonly related to <strong>low calcium<\/strong> absorption or intake and\/or <strong>low phosphate<\/strong>.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">CALCIPENIC (CALCIUM-DEFICIENT) RICKETS\/OSTEOMALACIA<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Pathophysiology<\/strong>\n<ul class=\"wp-block-list\">\n<li>Decreased <strong>intestinal absorption<\/strong> of calcium.\n<ul class=\"wp-block-list\">\n<li>Low dietary calcium OR decreased absorption (e.g., <a href=\"https:\/\/myendoconsult.com\/learn\/topics\/celiac-disease\/\"  data-wpil-monitor-id=\"345\">celiac disease<\/a>).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Vitamin D\u2013related<\/strong> deficits in calcium absorption.\n<ul class=\"wp-block-list\">\n<li>Ranges from vitamin D deficiency, 1\u03b1-hydroxylation defect, or receptor abnormalities.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Chronic hypocalcemia<\/strong> \u2192 <strong>secondary hyperparathyroidism<\/strong> \u2192 partial <a href=\"https:\/\/myendoconsult.com\/learn\/calcium-correction-for-albumin\/\"  data-wpil-monitor-id=\"346\">correction of calcium<\/a> but excretes phosphate \u2192 <strong>hypophosphatemia<\/strong>.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Net Effect<\/strong>\n<ul class=\"wp-block-list\">\n<li>Low\/low-normal serum calcium, <strong>low serum phosphate<\/strong>.<\/li>\n\n\n\n<li><strong>Increased PTH<\/strong> \u2192 high <a href=\"https:\/\/myendoconsult.com\/learn\/bone-turnover-markers-in-osteoporosis\/\"  data-wpil-monitor-id=\"267\">bone turnover<\/a> (osteoclast activity).<\/li>\n\n\n\n<li>Bone matrix laid down but <strong>not mineralized<\/strong> (rickets in children, osteomalacia in adults).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h3 class=\"wp-block-heading\">VITAMIN D SYNTHESIS &amp; DEFICIENCY<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Vitamin D Sources<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Skin synthesis<\/strong> (vitamin D3) from 7-dehydrocholesterol via sunlight UV.<\/li>\n\n\n\n<li><strong>Diet<\/strong> (ergocalciferol vitamin D2) from plants\/fish\/fortified products.<\/li>\n\n\n\n<li>Both forms hydroxylated in <strong>liver<\/strong> \u2192 25-hydroxyvitamin D (25[OH]D).<\/li>\n\n\n\n<li>25(OH)D further <strong>1\u03b1-hydroxylated<\/strong> in <strong>kidney<\/strong> \u2192 1,25-dihydroxyvitamin D (1,25[OH]2D).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Causes of Deficiency<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Low sunlight<\/strong> exposure.<\/li>\n\n\n\n<li><strong>Low dietary intake<\/strong>.<\/li>\n\n\n\n<li><strong>Malabsorption<\/strong> (e.g., gastric surgery, celiac).<\/li>\n\n\n\n<li><strong>Less 25(OH)D production<\/strong> in liver disease or <strong>less 1\u03b1-hydroxylation<\/strong> in kidney disease.<\/li>\n\n\n\n<li><strong>P450-inducing drugs<\/strong> (e.g., anticonvulsants) accelerating vitamin D metabolism.<\/li>\n\n\n\n<li><strong>Nephrotic syndrome<\/strong> \u2192 urinary loss of vitamin D\u2013binding protein.<\/li>\n\n\n\n<li><strong>End-organ resistance<\/strong> at vitamin D receptor.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Epidemiology &amp; Risk<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Vitamin D\u2013deficient rickets<\/strong> typically appears in children &lt;3 years.<\/li>\n\n\n\n<li><strong>Breastfed infants<\/strong> require extra vitamin D (400 IU\/day).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Treatment<\/strong>\n<ul class=\"wp-block-list\">\n<li>Vitamin D2 (ergocalciferol) often sufficient.<\/li>\n\n\n\n<li>Calcium intake \u22651000 mg\/day.<\/li>\n\n\n\n<li>Monitor serum levels (Ca, phosphate, 25[OH]D, alkaline phosphatase) + urine calcium.<\/li>\n\n\n\n<li>Bone healing confirmed by radiography.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">PSEUDOVITAMIN D\u2013DEFICIENCY RICKETS\/OSTEOMALACIA<\/h2>\n\n\n\n<h3 class=\"wp-block-heading\">TYPE 1: Renal 1\u03b1-Hydroxylase Deficiency<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Pathophysiology<\/strong>\n<ul class=\"wp-block-list\">\n<li>Autosomal recessive.<\/li>\n\n\n\n<li><strong>No\/minimal 1\u03b1-hydroxylation<\/strong> of 25(OH)D \u2192 low 1,25(OH)2D.<\/li>\n\n\n\n<li>Presents in infancy (~1st year) with:\n<ul class=\"wp-block-list\">\n<li><strong>Hypocalcemia<\/strong>, <strong>hypophosphatemia<\/strong>, elevated PTH (secondary), low 1,25(OH)2D, high alkaline phosphatase.<\/li>\n\n\n\n<li>Rickets\/osteomalacia features (bone deformities, muscle weakness, growth failure).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Treatment<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>Calcitriol<\/strong> lifelong (1 \u03bcg\/day typical).<\/li>\n\n\n\n<li>Adequate calcium supplementation.<\/li>\n\n\n\n<li>Avoid hypercalcemia\/hypercalciuria (overtreatment) to prevent nephrocalcinosis.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">TYPE 2: Hereditary Vitamin D\u2013Resistant Rickets<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Pathophysiology<\/strong>\n<ul class=\"wp-block-list\">\n<li>Autosomal recessive <strong>vitamin D\u2013receptor mutations<\/strong>.<\/li>\n\n\n\n<li>Tissues unresponsive to 1,25(OH)2D.<\/li>\n\n\n\n<li>Presents similarly in infancy\/childhood:\n<ul class=\"wp-block-list\">\n<li><strong>Hypocalcemia<\/strong>, <strong>hypophosphatemia<\/strong>, <strong>\u21911,25(OH)2D<\/strong> (3\u20135\u00d7 normal), high PTH, osteomalacic changes.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li>Some kindreds also have <strong>alopecia totalis<\/strong> (hair loss).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Treatment<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>High-dose calcitriol<\/strong> (5\u201360 \u03bcg\/day) to overcome receptor resistance if possible.<\/li>\n\n\n\n<li>Otherwise, prolonged IV calcium infusions.<\/li>\n\n\n\n<li>Monitor bone healing, lab parameters (Ca, phosphate, PTH, alkaline phosphatase).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">HYPOPHOSPHATEMIC RICKETS\/OSTEOMALACIA<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Core Mechanism<\/strong>\n<ul class=\"wp-block-list\">\n<li>Renal phosphate wasting (isolated or part of Fanconi syndrome).<\/li>\n\n\n\n<li><strong>Biochemical<\/strong>: Hypophosphatemia, normal Ca, normal\/high PTH, <strong>\u2191 FGF23<\/strong>.<\/li>\n\n\n\n<li>4 main groups:\n<ol class=\"wp-block-list\">\n<li><strong>X-linked<\/strong> (most common; PHEX gene mutation).<\/li>\n\n\n\n<li><strong>Autosomal dominant<\/strong> (activating mutations in FGF23).<\/li>\n\n\n\n<li><strong>Autosomal recessive<\/strong> (DMP1 mutations \u2192 \u2191 FGF23).<\/li>\n\n\n\n<li><strong>Hypercalciuric forms<\/strong> (Dent disease).<\/li>\n<\/ol>\n<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">X-Linked Hypophosphatemic Rickets<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Presentation<\/strong>\n<ul class=\"wp-block-list\">\n<li>Rickets signs\/symptoms + growth retardation.<\/li>\n\n\n\n<li><strong>Enthesopathy<\/strong> (tendon\/ligament calcifications), <strong>dental issues<\/strong> (early decay, abscess).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Typical Labs<\/strong>\n<ul class=\"wp-block-list\">\n<li>Low phosphate, low 1,25(OH)2D, normal Ca, normal\/\u2191 PTH, \u2191 FGF23, \u2191 urinary phosphate excretion, \u2191 alkaline phosphatase.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Therapy<\/strong>\n<ul class=\"wp-block-list\">\n<li>Oral <strong>phosphate<\/strong> + <strong>calcitriol<\/strong> (to limit secondary hyperparathyroidism).<\/li>\n\n\n\n<li>Monitor labs, bone radiographs. Over-suppression \u2192 risk <a href=\"https:\/\/myendoconsult.com\/learn\/topics\/hypercalcemia\/\"  data-wpil-monitor-id=\"266\">hypercalcemia<\/a>, hypercalciuria, nephrocalcinosis.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<h3 class=\"wp-block-heading\">Tumor-Induced Osteomalacia (Acquired)<\/h3>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Pathophysiology<\/strong>\n<ul class=\"wp-block-list\">\n<li>Small, benign <strong>mesenchymal tumors<\/strong> hypersecrete FGF23.<\/li>\n\n\n\n<li><strong>Identical labs<\/strong> to X-linked form but no personal\/family history.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Diagnosis &amp; Treatment<\/strong>\n<ul class=\"wp-block-list\">\n<li>Imaging (somatostatin receptor scintigraphy, full-body MRI) to find tumor.<\/li>\n\n\n\n<li><strong>Tumor removal<\/strong> cures the condition.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">RICKETS IN CHILDHOOD: CLINICAL MANIFESTATIONS<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>General<\/strong>\n<ul class=\"wp-block-list\">\n<li>Abnormal epiphyseal mineralization in growing bones \u2192 epiphyseal plate widening, irregular shape.<\/li>\n\n\n\n<li>Common in knees, costochondral junctions, distal forearm.<\/li>\n\n\n\n<li>Signs:\n<ul class=\"wp-block-list\">\n<li>\u201cRachitic rosary\u201d (costochondral thickening).<\/li>\n\n\n\n<li><strong>Wrist enlargement<\/strong>, <strong>bowed radius\/ulna<\/strong>.<\/li>\n\n\n\n<li>Genu varum (bowlegs) if child is ambulatory; genu valgum (knock-knee) in some.<\/li>\n\n\n\n<li>Delayed fontanelle closure, frontal bossing, craniotabes.<\/li>\n\n\n\n<li><strong>Harrison groove<\/strong> (diaphragmatic pull on softened ribs).<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Symptoms<\/strong>\n<ul class=\"wp-block-list\">\n<li>Skeletal pain, fractures, bone deformities, <a href=\"https:\/\/myendoconsult.com\/learn\/evaluation-of-short-stature\/\"  data-wpil-monitor-id=\"268\">short stature<\/a>, muscle weakness, hypotonia, delayed motor milestones.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Laboratory Profile<\/strong>\n<ul class=\"wp-block-list\">\n<li><strong>High alkaline phosphatase<\/strong> always.<\/li>\n\n\n\n<li>Hypocalcemia in <strong>calcipenic<\/strong> rickets; normal\/low in <strong>phosphopenic<\/strong> rickets.<\/li>\n\n\n\n<li>Hypophosphatemia in both.<\/li>\n\n\n\n<li><strong>Elevated PTH<\/strong> in calcipenic rickets; normal in hypophosphatemic rickets.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Radiographic Findings<\/strong>\n<ul class=\"wp-block-list\">\n<li>Widened growth plates, irregular metaphyses.<\/li>\n\n\n\n<li>Thinned cortices, poor trabeculation, subperiosteal erosions if hyperparathyroid.<\/li>\n\n\n\n<li><strong>Looser zones\/pseudofractures<\/strong> in advanced cases.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Diagnosis &amp; Management<\/strong>\n<ul class=\"wp-block-list\">\n<li>Detailed dietary, medication history.<\/li>\n\n\n\n<li>Labs: Ca, phosphate, PTH, 25(OH)D, + possible additional tests.<\/li>\n\n\n\n<li>Specific therapy based on cause (nutritional deficiency, pseudovitamin D deficiency, hypophosphatemia).<\/li>\n\n\n\n<li>Corrective therapy can allow natural remodeling &lt;4 yrs old; older children \u2192 permanent deformities.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">OSTEOMALACIA IN ADULTS: CLINICAL MANIFESTATIONS<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Definition<\/strong>\n<ul class=\"wp-block-list\">\n<li>Impaired mineralization of osteoid (adult equivalent to rickets).<\/li>\n\n\n\n<li>Often from <strong>hypophosphatemia<\/strong>, less commonly from <strong>hypocalcemia<\/strong> or low alkaline phosphatase activity (hypophosphatasia).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Presentation<\/strong>\n<ul class=\"wp-block-list\">\n<li>Range: Incidental osteopenia on X-ray \u2192 severe bone pain, proximal muscle weakness, fractures.<\/li>\n\n\n\n<li>Fractures typically at <strong>vertebrae<\/strong> (leading to compression), <strong>ribs<\/strong>, or long bones.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Imaging<\/strong>\n<ul class=\"wp-block-list\">\n<li>Diffuse osteopenia, cortical thinning.<\/li>\n\n\n\n<li>\u201cCodfish\u201d vertebrae from end-plate concavity.<\/li>\n\n\n\n<li><strong>Looser zones (pseudofractures)<\/strong>: radiolucent lines with sclerotic margins, perpendicular to cortex.<\/li>\n\n\n\n<li>Subperiosteal erosions if secondary hyperparathyroidism.<\/li>\n\n\n\n<li>Bowing deformities in severe longstanding disease (tibia, radius, ulna).<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Laboratory<\/strong>\n<ul class=\"wp-block-list\">\n<li>Dependent on underlying cause (e.g., low 25(OH)D, or abnormal phosphate, etc.).<\/li>\n\n\n\n<li>Elevated PTH if secondary hyperparathyroidism from low Ca.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Bone Biopsy<\/strong>\n<ul class=\"wp-block-list\">\n<li>Tetracycline labeling can confirm unmineralized osteoid seams, slow bone formation rate.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Treatment<\/strong>\n<ul class=\"wp-block-list\">\n<li>Correct underlying cause: e.g., <strong>vitamin D<\/strong> \u00b1 calcium in nutritional deficiency.<\/li>\n\n\n\n<li>Monitor with labs (Ca, phosphate, PTH, alkaline phosphatase) \u00b1 imaging.<\/li>\n<\/ul>\n<\/li>\n<\/ul>\n","protected":false},"excerpt":{"rendered":"<p>NUTRITIONAL-DEFICIENCY RICKETS AND OSTEOMALACIA CALCIPENIC (CALCIUM-DEFICIENT) RICKETS\/OSTEOMALACIA VITAMIN D SYNTHESIS &amp; DEFICIENCY PSEUDOVITAMIN D\u2013DEFICIENCY RICKETS\/OSTEOMALACIA TYPE 1: Renal 1\u03b1-Hydroxylase Deficiency TYPE 2: Hereditary Vitamin D\u2013Resistant Rickets HYPOPHOSPHATEMIC RICKETS\/OSTEOMALACIA X-Linked Hypophosphatemic Rickets Tumor-Induced Osteomalacia (Acquired) RICKETS IN CHILDHOOD: CLINICAL MANIFESTATIONS OSTEOMALACIA IN ADULTS: CLINICAL MANIFESTATIONS<\/p>\n","protected":false},"featured_media":0,"template":"","oen_topic_chapter":[687],"class_list":["post-4422541","oen_topic","type-oen_topic","status-publish","hentry","oen_topic_chapter-parathyroid-gland","post-wrapper","thrv_wrapper"],"_links":{"self":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422541","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic"}],"about":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/types\/oen_topic"}],"version-history":[{"count":4,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422541\/revisions"}],"predecessor-version":[{"id":4422865,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422541\/revisions\/4422865"}],"wp:attachment":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/media?parent=4422541"}],"wp:term":[{"taxonomy":"oen_topic_chapter","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic_chapter?post=4422541"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}