{"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 CONTRIBUTING TO BONE DISEASE IN CKD TREATMENT APPROACHES<\/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","post-wrapper","thrv_wrapper"],"_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}]}}