toxic efects on skeleton system
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Toxic effects ofHypervitaminosis A Lead poisoningBismuth intoxicationVinyl chloride poisoningFluorosisOchronosis
too much vitamin A in the body.
Causes• Acute -- caused by taking too much vitamin A over a short
period of time• Chronic -- occurs when too much of the vitamin is present
over a longer period
• One recognized cause is administration from 13-cis retenoic acid for treatment of cancers such as neuroblastoma
1.Hypervitaminosis A
Imaging findings• diffuse symmetric periostitis• may cause premature fusion of ossification centres• separation of cranial sutures• Tendenous/ligmentous calcification
• Main source of lead intoxication is from lead containing paint and lead containing pipes
• Absorption is greater in children than adults
Pathology• Lead concentrates in metaphyses of growing
bonesDistal femurBoth ends of tibiaDistal radius
2.Lead poisoning
Clinical findingsMusculoskeletal• Muscle and joint painSoft tissue• Blue-black line in gum margins• Laboratory findings • Serum Lead Level >1.2 umol/L• Urine lead level elevated
IMAGING FINDINGSBands of increased density at metaphyses of
tubular bones (growing bone) Bone in bone appearanceAbnormalities in bone modelling
Erlenmeyer flask appearance to distal femur
Frontal radiograph of both knees of a child with lead poisoning show dense metaphyseal bandsinvolving not only distal femurs and proximal tibias but proximal fibulas as well
Differential Diagnosisanaemia - chronic (eg, sickle cell
disease; thalassemia)
chemotherapy - e.g. Methotrexate
growth acceleration lines
treated leukemia
3.BISMUTH INTOXICATIONFollowing treatment for syphilis in the past
A similar appearance to that of lead poisoning
4.Vinyl chloride poisoningFound in workers in PVC manufactureCauses Raynaud’s phenomenon and a
characteristic acro-osteolysisSacroiliitisHeamangiosarcoma of liver
5.FLUOROSIS Chronic metabolic bone disease
Caused by ingestion of large amounts of fluoride through either water or food in geographic areas where high levels offluoride occur naturally.
Radiographic features Involvement of the axial skeleton is
characteristic, and changes are most marked in the
• Spine,Pelvis,Ribs Plan filmincreased bone density - osteosclerosisosteopaenia / osteoporosis trabecular blurring or hazinesscompact bone thickening
periosteal bone formationossification of the attachments of tendons,
ligaments, and musclesinterosseous membrane calcification ossification of the posterior longitudinal ligament
Early fluorosis bone deposition and thickening at the junctions
of trabeculae. sandlike, granular, or particle like bone structure
on radiographs.
Advanced fluorosis trabeculae are more generally thickened because
of new bone formation on the trabecular surface. If the trabeculae are fused, focal round densities
are seen in the medullary bone.Osteopenia (less common) also may occur in
fluorosis - especially in younger patients at an earlier stage
Calcification of the sacrotuberous ligament is considered a characteristic feature.
Differential DiagnosisHaematological causesmyelofibrosissickle cell diseaseMetabolic bone disordershyperthyroidismhypoparathyroidism
6.OchronosisAutosomal recessive metabolic disorder.Caused by lack of homogentisic acid
oxalate,which accumulates in the connective tissue.
Radiographic FeaturesPlain filmVertebral:• multi level disc space narrowing• intervertebral disc calcification• Kyphoscoliosis
Gross joint space narrowing of sacroiliac joint and intervertebral disc space narrowing and calcification