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Year : 2006  |  Volume : 16  |  Issue : 4  |  Page : 627-632
Pictorial essay: Radiographic skeletal changes in Sickle cell anemia

IGMC and Mayo Hospital Nagpur. Consultant Radiologist, Amarjyoti x-ray and Sonography clinic, Wardha road, Dhantoli Nagpur 12. Maharashtra State, India

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Date of Submission22-Aug-2005
Date of Acceptance10-Aug-2006

Keywords: Sickle cell Anemia

How to cite this article:
Phatak S V, Kolwadkar P K, Phatak M S. Pictorial essay: Radiographic skeletal changes in Sickle cell anemia. Indian J Radiol Imaging 2006;16:627-32

How to cite this URL:
Phatak S V, Kolwadkar P K, Phatak M S. Pictorial essay: Radiographic skeletal changes in Sickle cell anemia. Indian J Radiol Imaging [serial online] 2006 [cited 2020 Dec 5];16:627-32. Available from:
Introduction: - Sickle cell anemia is caused by production of abnormal hemoglobin which binds with other abnormal hemoglobin molecules within red blood cells and causes rigid deformation of the cell. Due to this deformity of shape there is impairment of passage of cell through small vessels, sludging and congestion of vascular bed to be followed by ischemia and infarction. Infarction is common throughout the body in patients with sickle cell anemia and involves bones, brain, lungs, kidneys, spleen and liver. Finally as red blood cells are abnormal they are removed from the circulation resulting into hemolytic anemia. The normal human hemoglobin molecule consists of 4 globin chains 2alpha and 2 beta chains. Abnormal hemoglobin is usually result of abnormality in beta chains and not in alpha chains. The beta globin chain is coded to chromosome 11 on the short arm. Sickle cell hemoglobin is formed (HbS) when the aminoacid valine is substituted for glutamic acid at the sixth position of beta chain which has far reaching effects on hemoglobin reactions, RBC morphology and hemodynamics. The Hb S beta chain has unusual propensity to bind with other Hb S chains when deoxygenated resulting into twisted ropelike structure composed primarily of two complete hemoglobin molecule strands with binding between beta chains process called polymerization. Polymerization is responsible for sickled or banana shape and dehydration of RBC 's in sickle cell anemia also appear to have increased binding affinity for vascular endothelium. [1]

Discussion: -The skeletal system of patients with sickle cell Anemia is remarkable for its lifelong preservation and frequent expansion of red (cellular marrow)[1] The main skeletal radiographic changes are seen in Sickle cell anemia are caused by bone marrow hyperplasia, infarcts and superadded infection. [2],[3],[4],[5],[6] Chronic anemia is responsible for hyperplasia of bone marrow seen in long bones as expansion in red bone marrow containing regions caused by remodelling. This is best shown in 1st metacarpal known as squaring of metacarpals, which is seen around 6 months of age as genetically determined HbS replaces fetal hemoglobin. Bone enlargement can also be seen in distal femur causing Erlenmeyer flask deformity. Changes induced by marrow hyperplasia are nonspecific as these can also be seen in chronic iron deficiency anemia, Hemoglobin E disease and Thalassemia, where changes are severe that includes extramedullary hematopoesis. [2] Marrow hyperplasia leads to thinning and crowding of trabeculae causing osteoporosis. In the diaphysis trabeculae becomes sparse while remaining trabeculae are thickend. Metaphyseal bone remains relatively dense. In cases of children changes are most evident in long bones and small tubular bones of hand and feet. In adolescence osteoporosis disappears due to conversion of red marrow to yellow marrow in extremities. Various patterns which are seen in skull are diploic thickening, granular texture, lamination of diploe and hair on end pattern. [7] Coarse granular or stippled pattern is best seen in upper parietal region. It may be first sign of developing bone marrow hyperplasia. [8] Cranial vault thickens with most contribution from diploic component and with resultant thinning of outer table. In a normal person with thick skull all component layers contribute to overall thickness. Presence of diploic layer more than 2.5 times the combined thickness of inner and outer table s suggests diseased state. Diploic thickening is significant in frontal and parietal region and does not involve squamous portion of temporal or occipital bone. [7] Diploic thickening is nonspecific as it is also found in other anemias like thalassemia, hereditary sperocytosis and severe iron deficiency anemia [9]. It is also seen in cases of Dilatin toxicity [10], after surgical treatment of hydrocephalus [11], cyanotic congenital heart disease [12] and pseudohypoparathyroidism [13] Sometimes in-patients with thick diploe curvilinear dense bone within lucent marrow parallal to inner table gives appearance of onion skin. Hair on end appearance is also observed as fine linear densities like spicules of bone perpendicular to inner table. This is frequently seen in thalassemia. [7] In spine marrow hyperplasia is reflected as coarse striated or lacy appearance of vertebra in children and adults both and may involve the whole length of spine [14] Compression deformity can also be a result of hyperplasia of bone marrow. In simple flattening rectilinear shape is preserved, only height to width ratio is altered. For objective assessment of simple flattening Diggs et al [15] determined normal adult height to width ratio in first four lumbar vertebrae and found it to be 1.0:1.4 in AP view and 1.0:1.2 in lateral view. With true flattening measurements clearly exceed this ratio [16] Simple flattening is seen in lower dorsal and lumbar region. Occasionally non-compressible disc smoothly depress end plate to create a concave deformity or a wedge shaped deformity which is seen in dorsal spine. [7] Sometimes persistent anterior vertebral notching is seen on lateral projection. Riggs and Rockett described that this notch is large in young children with sickle cell disease. [17] The first appearance of ischemic insult usually comes in sickle cell anemia in form of dactylitis called as hand foot syndrome seen after 3 months of age usually between 6-18 months and uncommon after 6 yrs.with disappearance of red marrow from tubular bones. Soft tissue swelling and periosteal reaction results if infarction is involving medullary cavity. If there is compromise of periosteal circulation diaphyseal cortical bone infarct seen with areas of bone destruction and patchy areas of new bone formation. Epiphysis and metaphysis is usually spared by virtue of multivessel supply. It may involve one or multiple bones. Feet are involved less than hand [2] When the long bone involvement is not severe no radiological findings are seen. In acute long bone infarct there is only medullary infarction seen well on Radionuclide bone scan, CT and MR can demonstrate medullary abnormalities. [18] With severe involvement and compromised periosteal circulation full thickness cortical destruction with periosteal reaction can be visualized. The periosteal reaction may actually become new cortex. Infarct can heal completely or with fibrosis. Calcification may or may not take place. Both full thickness or endocortical long bony infarcts tend to spare metaphysis due to collateral circulation. The classical site of long bone infarct is metadiaphyseal segment of shaft [19] Carpals and tarsal have blood supply by number vessels rather than a single nutrient artery. Tarsals are involved more than carpals. Radiologically destruction and osteopenia is visualized. [20] Necrotic bone marrow is a fertile site for secondary infection. Patients with sickle cell anemia have immunologic deficiencies making them susceptible to certain infections than other people. [21] Staphylococcus aureus Scientific Name Search  is a common offender [22] but  Salmonella More Details organisms also frequently involved. [23] Growth disturbances are seen after acute diaphyseal infarcts or osteomyelitis are due to deficiency in nutrient artery circulation. To the central region of metaphyseal side of growth plate. [24] Triangular or coned epiphysis is probably due to metaphyseal deformity. Benign cyst or malignant neoplasm may develop at the site of medullary scarring from old infarcts. Fibrosarcoma, osteosarcoma and fibrous histiocytoma are the most common of the neoplasms [2]. Epiphyseal avascular necrosis is less common before growth plate fusion when it occurs at the hip before fusion capital femoral epiphysis and later femoral head have a diffusely flattened or mushroom appearance associated with widened femoral neck. [25] After growth plate closure segmental involvement typically in weight bearing anterosuperior portion of femoral head is seen. Radiographic findings include a curvilinear lucency beneath the subarticular cortex, the crescent sign later on dense homogenous dome of appearance also known as snowcap appearance and flattening and step like depressions of subarticular cortex are seen eventually secondary osteoarthritis develops. Shoulder is involved less as compared to hip but radiological findings are similar. In adult patients diaphyseal sclerosis is visualized due to endo cortical sclerosis, cortical thickening and medullary calcification. [2] Spine show evidence of ischemic changes in form of vertebral sclerosis, massive collapse of centra and central cupping of end plate. Like other bones in body infarcts also occur in spine with clinical presentation of recurrent attacks of back pain present radiographically as small areas of increased density, coalesce and produce diffuse vertebral density [15] It is seen in old patients with differentials including chronic renal failure, carcinoma prostate, myelofibrosis and fluoride intoxication. [7] Massive collapse of centra is visualized in lower dorsal and lumbar region .It can involve two or three contiguous vertebrae with narrow disc space. Some of these lesions are produced in part by osteomyelitis. [26] A very typical change is seen in vertebral end plates of a vertebrae in many patients of sickle cell anemia, causing a central cupping [27] A concave depression is seen in both upper and lower surfaces of centrum show a concave depression confined to middle 50-60% of the endplate, located at or slightly behind the midcoronal plane. The floor of the cup is flat and cortical bone at its base has a more rectilinear and angular contour as compared to curved or arcuate shape of simple collapse. It represents bulky capital" H"[7] This distinctive feature is seen on lateral view. Upper and lower end plates are symmetrically involved but occasionally confined to only one surface. [28] Exact mechanism of this deformity is not known but said to be effect of chronic local ischemia [26],[29] Occasionally different pathological conditions may show morphologically similar changes like thalassemia major [30], gauchers disease [31], homocystinuria [32], chronic renal disease [33] paroxysmal nocturnal hemoglobinuria, alcoholism, histiocytosis x with healing vertebra plana and young woman on birth control pills. [7]

   References Top

1.Gael Lonergan et al Sickle Cell Anemia Radiographics 2001;21:971-994  Back to cited text no. 1    
2.Stanley P.Bohrer Bone changes in extremities in sickle cell anemia Seminars in Roentgenology vol XXII No.3 (July) 1987:176-185.  Back to cited text no. 2    
3.J.George Teplik, Marvin E Haskin Sickle cell disease In Roentgenologic diagnosis, Volume II, 3rd edition WBSaunders and company Philadelphia 1976:1148-1154  Back to cited text no. 3    
4.David Sutton Text book of Radiology Sickle cell anemia, Reprint, E and S Livingstone Edinburgh and London 1971:127-129.  Back to cited text no. 4    
5.Grainger and Allisons Diagnostic Radiology a textbook of medical imaging Sickle cell disease Churchill Livingstone New York, Third edition Volume two 1997:1693-6.  Back to cited text no. 5    
6.Jack Edeikin, Philip J.Hodes The Anemias In Roentgen diagnosis of diseases of bone Volume one, Asian edition, Williams and Wilkins company Baltimore 1973:360-374.  Back to cited text no. 6    
7.Jack Reynolds: The skull and spine Seminars in RoentgenologyVolXXII, no.3 (July) 1987:168-175.  Back to cited text no. 7    
8.Reynolds J: An evaluation of some roentgenographic signs in sickle cell anemia and its variants South Med J 1962; 55:1123-1128.  Back to cited text no. 8    
9.Burko H, Mellins HZ, and Waston J: Skull changes of iron deficiency anemia simulating congenital hemolytic anemia AJR 1961; 86:447-452.  Back to cited text no. 9    
10.Kattan KR: Calvarial thickening after Dilantin medication AJR 1970; 110:102-105.  Back to cited text no. 10    
11.MoseleyJE, RobinowitzJG, DziadiwR: Hyperostosis cranii ex vacuo Radiology; 1966:1105-1107.  Back to cited text no. 11    
12.Fellows KE, Rosenthal A: Extracardiac roentgenographic abnormalities in cyanotic congenital heart disease AJR 1972; 114:371-379.  Back to cited text no. 12    
13.Cusmano JP, BakerDH, Finby N: Pseudohypoparathyroidism Radiology 1956; 67:845-853.  Back to cited text no. 13    
14.Carrol DS, EvansJW Roentgen findings in sickle cell anemia Radiology 1949; 53:834-845.  Back to cited text no. 14    
15.Diggs LW, Pulliam HM, and KingJC the bone changes in sickle cell anemia South Med J 1937; 30:249-259.  Back to cited text no. 15    
16.Golding JSR The bone changes in sickle cell anemia Ann R coll Surg Engl 1956; 19:296-315.  Back to cited text no. 16    
17.RiggsW, RockettJF: Roentgen chest findings in childhood sickle cell anemia AJR 1968; 104:838-845.  Back to cited text no. 17    
18.RaoVM, FishmanM, MitchellDG et al Painful sickle cell crisis: Bone marrow patterns observed with MR imaging Radiology 1986; 161:211-215.  Back to cited text no. 18    
19.BohrerSP: Acute long bone diaphyseal infarcts in sickle cell disease Br J Radiol 1970; 43:685-697.  Back to cited text no. 19    
20.Bohrer SP: Fractures complicating bone infarcts and /or osteomyelitis in sickle cell disease Clin Radiol1971; 22:83-88.  Back to cited text no. 20    
21.Barrett Connor E: Bacterial infections and sickle cell anemia An analysis of 250 infections in 166 patients and a review of literature Medicine1971; 50:97-112.  Back to cited text no. 21    
22.Sadat Ali, Sankaran kutty, KuttyK: Recent observations on osteomyelitis in sickle cell disease Int orthop1985; 9:97-99.  Back to cited text no. 22    
23.AdeyokunnuAA, HendrickseRG: Salmonella osteomyelitis in childhood A report of 63 cases seen in Nigerian children of whom 57 had sickle cell anemia Arch Dis Child 1980; 55:175-184.  Back to cited text no. 23    
24.Cockshott WP: Dactylitis and growth disorders Br.J Radiol 1965; 36:19-26.  Back to cited text no. 24    
25.Lee REJ, Golding JSR, Serjent GR The radiological features of avascular necrosis of femoral head in homozygous sickle cell disease Clin Radiol 1981; 32:205-214.  Back to cited text no. 25    
26.Borton CJ, Cockshott WP: Bone changes in Hemoglobin Sickle cell disease AJR 1962; 88:523-32.  Back to cited text no. 26    
27.Reynolds J: The radiological feature of sickle cell disease and related hemoglobinopathies Springfield: CC Thomas 1965.  Back to cited text no. 27    
28.Martel W: A reevaluation of "Fishvertebra"sign in sickle cell hemoglobinopathy. (Reviewers comment) Invest Radiol 1968; 3:128-129.  Back to cited text no. 28    
29.Reynolds J: A reevaluation of the fish vertebra sign in sickle cell anemia AJR 1966; 97:693-707.  Back to cited text no. 29    
30.Cassady JR, BerdonWE, and BakerDH: The typical spine changes of sickle cell anemia in a patient of thalassemia major (Cooleys anemia) Radiology 1967; 89:1065-68.  Back to cited text no. 30    
31.Hansen GC, GoldRH: Central depression of multiple vertebral end plates: A "pathognomonic"sign of sickle hemoglobinopathy in gauchers disease AJR 1977; 129:343-344.  Back to cited text no. 31    
32.WestrmanWP, GreenfieldGB, WongPWK:"Fish vertebrae"homocystinuria and sickle cell disease JAMA1974; 230:261-262.  Back to cited text no. 32    
33.Zitter FMH: central vertebral endplate depression in chronic renal disease: Report of two cases AJR 1979; 132:809-811.  Back to cited text no. 33    

Correspondence Address:
S V Phatak
Honorary Asst.Prof Radio-diagnosis, IGMC and Mayo Hospital Nagpur. Consultant Radiologist, Amarjyoti x-ray and Sonography clinic, Wardha road, Dhantoli Nagpur 12. Maharashtra State
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Source of Support: None, Conflict of Interest: None

DOI: 10.4103/0971-3026.32285

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  [Figure - 1], [Figure - 2], [Figure - 3], [Figure - 4], [Figure - 5], [Figure - 6], [Figure - 7], [Figure - 8], [Figure - 9], [Figure - 10], [Figure - 11], [Figure - 12], [Figure - 13], [Figure - 14], [Figure - 15], [Figure - 16]

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