{"id":4422523,"date":"2025-01-11T22:39:35","date_gmt":"2025-01-12T04:39:35","guid":{"rendered":"https:\/\/myendoconsult.com\/learn\/topics\/renal-osteodystrophy\/"},"modified":"2025-01-13T06:35:21","modified_gmt":"2025-01-13T12:35:21","slug":"renal-osteodystrophy","status":"publish","type":"oen_topic","link":"https:\/\/myendoconsult.com\/learn\/topics\/renal-osteodystrophy\/","title":{"rendered":"Renal Osteodystrophy"},"content":{"rendered":"\n<h2 class=\"wp-block-heading\">OVERVIEW OF RENAL OSTEODYSTROPHY<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Definition<\/strong>: Refers to bone morphology alterations found in patients with <strong>chronic kidney disease (CKD)<\/strong>.<\/li>\n\n\n\n<li><strong>Common Forms<\/strong>:\n<ol class=\"wp-block-list\">\n<li><strong>High <a href=\"https:\/\/myendoconsult.com\/learn\/bone-turnover-markers-in-osteoporosis\/\" data-wpil-monitor-id=\"262\">bone turnover<\/a><\/strong> due to secondary or tertiary hyperparathyroidism (HPT), including osteitis fibrosa cystica<\/li>\n\n\n\n<li><strong>Low bone turnover<\/strong> with adynamic bone disease<\/li>\n\n\n\n<li><strong>Low bone turnover<\/strong> combined with <strong>increased unmineralized bone<\/strong> (osteomalacia)<\/li>\n\n\n\n<li><strong>\u03b2\u2082-microglobulin\u2013associated<\/strong> amyloid deposits forming bone cysts<\/li>\n\n\n\n<li><strong>Mixed osteodystrophy<\/strong> with both high- and low-turnover elements<\/li>\n<\/ol>\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\">TWO KEY PATHOLOGIC FACTORS IN CKD<\/h3>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Decreased Renal Conversion<\/strong> of 25(OH)D \u2192 1,25(OH)\u2082D (calcitriol)<\/li>\n\n\n\n<li><strong>Decreased Ability to Excrete<\/strong> Inorganic Phosphate (Pi)<\/li>\n<\/ol>\n\n\n\n<hr class=\"wp-block-separator has-alpha-channel-opacity\"\/>\n\n\n\n<h2 class=\"wp-block-heading\">SECONDARY HYPERPARATHYROIDISM (HPT)<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li>As <strong>GFR decreases<\/strong>, the filtered load of phosphate falls \u2192 serum phosphate rises \u2192 serum calcium (Ca\u00b2\u207a) drops \u2192 <strong>PTH increases<\/strong> (secondary HPT).<\/li>\n\n\n\n<li>Also, <strong>reduced 1,25(OH)\u2082D<\/strong> production (due to decreased renal mass) \u2192 less calcium absorbed from gut \u2192 further PTH rise.<\/li>\n\n\n\n<li>Although initially PTH partially corrects these abnormalities (by lowering phosphate reabsorption, raising bone resorption of calcium, and boosting calcitriol), over time it becomes <strong>maladaptive<\/strong> as kidney function worsens.<\/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\">TERTIARY HYPERPARATHYROIDISM<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Definition<\/strong>: Refractory hypersecretion of <a href=\"https:\/\/myendoconsult.com\/learn\/parathyroid-hormone-pth-lab-assessment\/\" data-wpil-monitor-id=\"260\">PTH with severe parathyroid<\/a> hyperplasia or neoplastic transformation (monoclonal adenomas).<\/li>\n\n\n\n<li><strong>Pathophysiology<\/strong>:\n<ul class=\"wp-block-list\">\n<li>Failing kidneys can\u2019t excrete phosphate despite high PTH \u2192 continued bone resorption elevates both calcium + phosphate \u2192 <a href=\"https:\/\/myendoconsult.com\/learn\/topics\/hypercalcemia\/\" data-wpil-monitor-id=\"261\">hypercalcemia<\/a> \u2192 metastatic calcification (soft tissues, joints, arteries) \u2192 can cause ischemia, gangrene.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Bone Findings<\/strong>: Subperiosteal resorption, cysts, osteitis fibrosa cystica (brown tumors), fractures, \u201csalt-and-pepper\u201d skull, \u201cband\u201d vertebral sclerosis.<\/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\">ADYNAMIC BONE DISEASE<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Most common<\/strong> in dialysis patients (peritoneal or hemodialysis).<\/li>\n\n\n\n<li><strong>Low bone turnover<\/strong>, absence of bone cell activity \u2192 no osteoid formation increase (unlike osteomalacia).<\/li>\n\n\n\n<li>Associated with <strong>excess PTH suppression<\/strong> (e.g., due to calcium-based phosphate binders and vitamin D analogues).<\/li>\n\n\n\n<li><strong>Clinical<\/strong>: Raises fracture risk (e.g., hip fractures).<\/li>\n\n\n\n<li><strong>Biochemical Clue<\/strong>: Often serum PTH &lt;100 pg\/mL.<\/li>\n\n\n\n<li><strong>Key Management<\/strong>: Allow PTH to rise by reducing or discontinuing calcium-based binders \/ vitamin D analogues.<\/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 (WITH RENAL FAILURE)<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Pathophysiology<\/strong>: Decreased bone turnover + excess unmineralized bone, from <strong>vitamin D deficiency<\/strong> or <strong>aluminum intoxication<\/strong>.<\/li>\n\n\n\n<li><strong>Radiographic Findings<\/strong>:\n<ul class=\"wp-block-list\">\n<li><strong>Looser zones (pseudofractures)<\/strong> = narrow radiolucent lines, perpendicular to cortex, with sclerotic borders; bilateral and symmetric.<\/li>\n\n\n\n<li>Bone resorption at lateral clavicle ends.<\/li>\n\n\n\n<li><strong>Milkman syndrome<\/strong> = bilateral symmetric pseudofractures in osteomalacia.<\/li>\n<\/ul>\n<\/li>\n\n\n\n<li><strong>Fractures<\/strong>: Minimal or no trauma, commonly in long bones (e.g., hip), ribs, vertebrae.<\/li>\n\n\n\n<li><strong>Diagnostic<\/strong>: Bone biopsy after tetracycline labeling can confirm decreased mineralization.<\/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\">OTHER FACTORS CONTRIBUTING TO BONE DISEASE IN CKD<\/h2>\n\n\n\n<ul class=\"wp-block-list\">\n<li><strong>Vitamin K deficiency<\/strong> (needed for bone matrix protein carboxylation).<\/li>\n\n\n\n<li><strong>Bone morphogenetic protein-7<\/strong> deficiency (kidney normally produces BMP-7 to aid osteoblast differentiation).<\/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\">TREATMENT APPROACHES<\/h2>\n\n\n\n<ol class=\"wp-block-list\">\n<li><strong>Normalize serum Ca\u00b2\u207a and phosphate<\/strong> levels while minimizing aluminum.<\/li>\n\n\n\n<li><strong>Dietary phosphate restriction<\/strong> plus phosphate binders if GFR &lt;25% normal.<\/li>\n\n\n\n<li><strong>Vitamin D supplementation<\/strong> to maintain normal 1,25(OH)\u2082D levels.<\/li>\n\n\n\n<li><strong>Parathyroidectomy<\/strong> for tertiary HPT or intractable secondary HPT with severe hypercalcemia \/ bone disease.<\/li>\n<\/ol>\n","protected":false},"excerpt":{"rendered":"<p>OVERVIEW OF RENAL OSTEODYSTROPHY TWO KEY PATHOLOGIC FACTORS IN CKD SECONDARY HYPERPARATHYROIDISM (HPT) TERTIARY HYPERPARATHYROIDISM ADYNAMIC BONE DISEASE OSTEOMALACIA (WITH RENAL FAILURE) OTHER FACTORS&hellip;<\/p>\n","protected":false},"featured_media":0,"template":"","oen_topic_chapter":[687],"class_list":["post-4422523","oen_topic","type-oen_topic","status-publish","hentry","oen_topic_chapter-parathyroid-gland"],"_links":{"self":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422523","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\/4422523\/revisions"}],"predecessor-version":[{"id":4422869,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic\/4422523\/revisions\/4422869"}],"wp:attachment":[{"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/media?parent=4422523"}],"wp:term":[{"taxonomy":"oen_topic_chapter","embeddable":true,"href":"https:\/\/myendoconsult.com\/learn\/wp-json\/wp\/v2\/oen_topic_chapter?post=4422523"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}