Endocrine/Metabolic Disorders and Crystal-induced Diseases

A. Scheurecker and J. Kramer


6    Endocrine/Metabolic Disorders and Crystal-induced Diseases


Osteomalacia and Rickets



Definition


Osteomalacia and rickets both are characterized by inadequate calcification of newly formed bone matrix with accumulation of osteoid. In rickets, there is additional involvement of the growth plate.


Pathology


Image  causes:



–   deficiency in active form of vitamin


–   impaired vitamin D metabolism


–   calcium deficiency


–   impaired phosphate metabolism


–   gastrointestinal malabsorption


Image  inadequate or delayed osteoid mineralization in compact and cancellous bone


Image  rickets: disorganization in the growth plate and adjacent metaphysis


Clinical Signs


Image  bone pain


Image  muscular weakness and adynamia


Image  skeletal deformity (bellshaped thorax, fish vertebrae, rachitic rosary, varus or valgus deformity of knee)


Diagnostic Evaluation


Image (→ primary method of choice)


Recommended Radiography Projections


Image  standard projections of the knee joint in two planes


Findings


Image  rickets:



–   widening of the growth plate


–   diminished density on the metaphyseal side of the growth plate


–   widening and “cupping” of the metaphysis


–   disorganization and fraying of metaphyseal cancellous bone


–   deossification and indistinct margin of epiphyseal ossification centers


–   abnormal curvatures (saber tibia)


Image  osteomalacia:



–   diminished bone density and indistinct fine bone structure (ground-glass appearance), thinning of compact bone


–   thickening of long tubular bones from sub periosteal osteoid deposition


–   Looser zones of transformation


Image (→ complementary method for osteomalacia)


Image  99mTc whole body scan is positive at typical (osteomalacia) Looser zones


Role of Imaging



Image  identification of abnormal bone density and structure


Image  identification of Looser zones


Image  demonstrate typical changes in rickets involving the growth plate, metaphysis, and ossification centers


Basic Treatment Strategies



Image  vitamin D replacement


Image  UV irradiation


Image  normalization of serum phosphate and serum calcium levels


Osteoporosis


Definition


Osteoporosis involves a decrease in bone mass, structural changes to bone tissue and deteriorating osseous functions that lead to an increased risk of fracture.


Pathology


Image  bone atrophy, predominantly caused by pathologically increasing bone loss with normal new bone formation (exception: senile osteoporosis)


Image  thinning and rarification of trabeculae


Image  thinning of cortical bone


Generalized Osteoporosis


Role of Imaging



Image  identification of abnormal bone density and structure


Image  identification of pathologic fractures


Pathology


Image  primary osteoporosis:



–   type I osteoporosis:


postmenopausal osteoporosis


–   type II osteoporosis:


senile osteoporosis


–   idiopathic osteoporosis:


juvenile, presenile


Image  secondary osteoporosis:



–   endocrine


–   calcium deficiency related to malabsorption


–   inactivity induced atrophy


–   hereditary disorders (e.g., osteogenesis imperfecta)


–   rheumatic diseases


–   drug-induced (cortisone, antacids)


Clinical Signs


Image  pain only with fracture (trauma usually inadequate)


Diagnostic Evaluation


Image


Recommended Radiography Projections


Image  standard projections


Findings


Image  more prominent trabecular pattern due to loss of cancellous bone


Image  thinning of cortical bone


Image  muscle and ligament insertions clearly standing out


Image  important: impossible to quantify osteoporosis


Image


Image  only as supplementary diagnostic procedure for complicated or occult fractures


Basic Treatment Strategies



Image  drug therapy depending on cause of osteoporosis


Image  avoid trauma


Image  minimization of risk factors (poor diet, nicotine, lack of activity)


Regional Osteoporosis


Inactivity-induced Osteoporosis


Pathology


Image  venous stasis due to failure of muscle pump


Image  active hyperemia from nerve damage



Diagnostic Evaluation (Figs. 6.1, 6.2)


Image (→ method of choice)


Findings


Image  homogenous or bandlike decreases in bone density affecting the metaphysis or appearing in patches



Image


Fig. 6.1a,b Image Inactivity-induced osteoporosis.


Conventional radiograph, AP, and lateral: mixed homogeneous and patchy decreases in bone density with clear trabecular pattern and cortical thinning as a result of inactivity following trauma.



Image


Fig. 6.2 a–c Image Inactivity-induced osteoporosis.


Coarse, strandlike subchondral bone structure and patchy areas of high signal.


a  MRI sagittal section, T1.


b  MRI coronal section, T1.


c  MRI sagittal section, STIR.


Regional Migratory (Transient) Osteoporosis


Pathology


Image  very rapidly developing osteoporosis of the joint


Image  self-limiting and reversible


Image  migratory character: after abatement, attack of further joints, generally next closest


Image  no history of trauma or immobilization


Clinical Signs


Image  localized pain and swelling


Diagnostic Evaluation


Image


Findings


Image  moderate osteopenia


Image  certain segments may be more heavily involved (e.g., medial femoral condyle)


Image


Recommended Sequences


Image  short tau inversion recovery (STIR)


Findings


Image  high-signal bone marrow edema (Fig. 6.3)



Image


Fig. 6.3a,b Image Transient regional osteoporosis.


a  MRI coronal section, T1 SE: diffuse hypointensity in the medial femoral condyle.


b  MRI coronal section, STIR sequence: diffuse high signal bone marrow edema in the medial femoral condyle.


Aggressive Regional Osteoporosis


Pathology


Image  rapidly progressing patchy osteoporosis


Image  osteoclastic bone resorption caused by active or passive hyperemia


Clinical Signs


Image  nonspecific pain


Image  posttraumatic or with trophic disorders (e.g., lymphedema)


Diagnostic Evaluation


Image (→ method of choice)


Recommended Radiography Projections


Image  knee joint in two planes with adjacent parts of lower and upper leg


Findings


Image  frayed cortical bone with subperiosteal and endosteal osteolytic lesions (appearance comparable to metastasis)


Image


Image  only as a supplemental procedure to exclude presence of blastoma


Sudeck Atrophy (Reflex Sympathetic Dystrophy Syndrome)


Role of Imaging



Image  identification of abnormal density and structure of cortical and cancellous bone


Image  exclusion of arthritis if intra-articular erosions absent


Image  in Sudeck atrophy, evaluation of soft tissue changes according to stage


Pathology


Image  microcirculation disorder resulting from dysfunctional sympathetic vasoconstrictor neurons


Image  trophic disorder involving bone and periarticular soft tissue structures


Image  stages in disease course:



–   stage I-early stage: soft tissue edema


–   stage II-acute stage: decrease in bone density, bone resorption in cortical and cancellous bone, marked inflammatory dystrophic soft tissue swelling


–   stage III-healing stage: resolution of soft tissue swelling and decrease in bone density with coarse strandlike cancellous bone structure


–   stage IV-defect stage: soft tissue atrophy and moderate loss of bone density with coarsening of cancellous architecture


Clinical Signs


Image  painful swelling and hypersensitivity


Image  livid skin coloration


Image  functional limitation


Diagnostic Evaluation


Image (→ method of choice)


Recommended Radiography Projections


Image  standard projections

Jan 17, 2016 | Posted by in MUSCULOSKELETAL IMAGING | Comments Off on Endocrine/Metabolic Disorders and Crystal-induced Diseases
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