DIAGNOSTIC APPROACH TO MYELOPATHIES

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1 review rticles DIAGNOSTIC APPROACH TO MYELOPATHIES Enfoque dignóstico de ls mieloptís An Mrí Grndos Sánchez 1 Lin Mrí Grcí Posd 2 Césr Andrés Orteg Toscno 2 Alejndr López López 2 Key words (MeSH) Spinl cord Spinl cord diseses Mgnetic resonnce imging Plrs clve (DeCS) Médul espinl Enfermeddes de l médul espinl Imgen por resonnci mgnétic SUMMARY Myelopthy is rod term tht refers to spinl cord involvement of multiple etiologies. Spinl cord diseses often hve devstting consequences, rnging from qudriplegi nd prplegi to severe sensory deficits due to its confinement in very smll re. Mny of these diseses re potentilly reversile if they re recognized on time, hence the importnce of recognizing the significnce of mgnetic resonnce imging when pproching multifctoril disese considered s one of the most criticl neurologicl emergencies, where prognosis depends on n erly nd ccurte dignosis. RESUMEN Mieloptí es un término generl que hce referenci l fectción medulr por múltiples etiologís. Ls enfermeddes de l médul espinl tienen con frecuenci consecuencis devstdors: pueden producir cudriplejí, prplejí y déficits sensitivos grves deido que l médul espinl está contenid en un cnl de áre pequeñ. Muchs de ests enfermeddes de l médul espinl son reversiles si se reconocen con oportunidd, por ello los rdiólogos deen sensiilizrse sore l importnci de ls imágenes por resonnci mgnétic en el enfoque de un ptologí multifctoril en l cul el pronóstico depende del dignóstico precoz y preciso, y por ello constituyen un de ls urgencis neurológics más importntes. 1 Neurordiologist, Fundción Vlle de Lili, Cli, Colomi. 2 Rdiology resident physicin, Universidd CES, Medellín, Colomi. Introduction The term myelopthy descries pthologic conditions tht cuse spinl cord, meningel or perimeningel spce dmge or dysfunction. Trumtic injuries, vsculr diseses, infections nd inflmmtory or utoimmune processes my ffect the spinl cord (1) due to its confinement in very smll spce. Spinl cord injuries usully hve devstting consequences such s qudriplegi, prplegi nd severe sensory deficits. The history, n dequte neurologicl exmintion nd the study of the cererospinl fluid (CSF) guide the dignosis of spinl cord injuries. However, imging is of gret importnce in order to home in on the dignosis nd clssify the etiology ppropritely (2-3). Mny of the processes ffecting the spinl cord my e reversile if recognized nd treted erly. The vst mjority of spinl cord diseses my e treted mediclly, with surgicl tretment reserved for compressive disorders, which constitute neurologicl emergency (2). This pper reviews the different etiologies, divided into compressive nd non-compressive. Definition nd clinicl picture It is importnt not to mistke myelopthy for myelitis. Although oth terms refer to spinl Rev Colom Rdiol. 2011; 22:(3):1-21 1

2 cord compromise due to pthologicl event, myelopthy hs multiple etiologies, while myelitis is used to refer to inflmmtory or infectious processes (1,4). Acute trnsverse myelopthy (includes non-inflmmtory etiologies) nd trnsverse myelitis hve een used s synonyms in the pulished literture (5). Findings of spinl trct injuries, certin degree of sensory dysfunction, or urinry retention, point to spinl cord injury. There re certin conditions tht my mimic myelopthy, such s myopthy or disorders of the neuromusculr junction, ut the sence of sensory deficit rules them out. On the other hnd, ilterl frontl mesil lesions my mimic myelopthy ut they re ssocited with uli or other signs of frontl dysfunction (6). Myelopthies my hve vrile course nd my mnifest s single event or s multi-phsic or recurrent disese. The ltter is rre nd is usully secondry to demyelinting diseses, vsculr mlformtions of the spinl cord, or systemic diseses (4,5). The centrl nervous system (CNS) dmge my e monofocl s in trnsverse myelitis nd optic neuritis, or multifocl s in cute disseminted encephlomyelitis (ADEM) (rin nd spinl cord), neuromyelitis optic (optic nerve nd spinl cord) nd multiple sclerosis (MS) (ny re of the neurl xis) (4). Spinl cord pthologies my e clssified s cute, sucute/ intermittent (6) or chronic, depending on the time course, the extent of the involvement, the clinicl picture or syndrome, or the etiology (2-4,6,7). Ptients with myelopthies ut no evident lesions, or who present with multiple lesions of chronic ppernce on mgnetic resonnce imging, must e questioned out prior sutle symptoms (6). Acute onset tht worsens within hours or dys points to spinl cord infrct or hemorrhge. When symptoms re recent, it is of prmount importnce to rule out surgicl emergency. This requires immedite imging work-up, idelly totl spine mgnetic resonnce (MR). If there is evidence of spinl cord compression due to n cute lesion (epidurl metstsis or scess), definitive mngement is required in order to void dmge or to dequtely mnge ll other potentil dignoses. If the symptoms progress for more thn three weeks, trnsverse myelitis is improle, nd other conditions must e considered, such s spinl tumor, chronic compressive disese, durl rterio-venous fistul, metolic disorder, srcoidosis, or degenertive process (6). Spinl cord syndromes present with typicl signs nd symptoms cused y lesion of specific trct in specific loction tht my led to the etiologicl dignosis. They re clssified s follows (2,6,8): Complete spinl cord: involvement of ll the trcts (trum, compression or cute trnsverse myelitis). Brown Séqurd or hemi-spinl cord syndrome: ipsilterl cortico-spinl trct, posterior columns nd contrlterl spinothlmic trct (multiple sclerosis nd compression). Anterior spinl cord syndrome: nterior horns, corticospinl, spinothlmic nd utonomic trcts (nterior spinl rtery infrct nd multiple sclerosis). 2 Posterior spinl cord syndrome: posterior columns (vitmin B12 or copper deficiency). Centrl syndrome: spino-thlmic crossing, cortico-spinl nd utonomic trcts (syringomyeli, neuromyelitis optic). Medullry cone: scrl emerging fires (post-virl myelitis). Cud equin: cud equin nerves (cute cytomeglovirus infection, polyrdiculits nd compression) Trctopthies: selective disorders (vitmin B12 deficiency, prneoplstic myelopthy nd multiple sclerosis). There re cses where the etiology is never identified, nd they re clssified s idiopthic myelopthy. In 2001, De Seze et l. found tht 43% of cute myelopthies were secondry to multiple sclerosis; 16.5% were due to systemic disese; 14% to spinl cord infrct; 6% to n infectious disese; 4% were secondry to rdition; nd 16.5% were idiopthic (9). Moore et l. found tht in cses of non-trumtic injury, 23.6% were due to cervicl spondylolysis; 17.8% to multiple sclerosis; 16.4% to neoplstic lesion; 4.1% to motor neuron disese; nd 18.6% were idiopthic or of unknown etiology (10). Chronic myelopthies include, mong others, spondylotic myelopthy, vsculr mlformtions, retrovirus-ssocited myelopthy (humn immunodeficiency virus), syringomyeli, chronic myelopthy due to multiple sclerosis, comined sucute degenertion (vitmin B12 deficiency), tes dorslis, nd fmilil spstic prplegi. Bsed on the Sicrd nd Forstier clssifiction tht divides the disese into compressive nd non-compressive, in reltion to surchnoid spce ostruction, Tle 1 shows list of the different etiologies (2-3,11). Compressive myelopthies Compressive diseses of the spinl cord re divided into cute nd chronic, including degenertive chnges, trum, tumor infiltrtion, vsculr mlformtions, infections with scess formtion, nd syringomyeli (Tle 1). Ptients with clinicl findings of compressive myelopthy tht show extensive (more thn three verterl segments) fusiform spinl cord hyperintensity in T2 weighted sequences, re often mistkenly thought to hve optic neuritis, or clssified s idiopthic. This delys surgicl tretment when other cuses such s stenosis of the spinl cnl re not tken into considertion (9). Compressive disese is the min cuse of myelopthy in older ptients. It hs chronic course nd usully does not recur (7). High intensity signls in T2 imges is explined y myelomlci, gliosis, tethering dmge, vsculr or inflmmtory edem, demyelintion nd vcuolr chnges. Gdolinium enhncement is limited to the region of mximum compression (12). Kelley et l. found tht none of the ptients with compressive myelopthy improved with intrvenous corticosteroids, while ptients with inflmmtory myelopthies did improve, invlidting the hypothesis of trumtic inflmmtory demyelintion. Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

3 Surgery improved or stilized ll ptients with compressive disese, consistent with the hypothesis of spinl cord edem or reversile ischemi in compression. These findings support the rgument tht the clinicl nd imging findings my differentite those ptients who will enefit from surgicl decompression (12). In 2007, Yukw et l. found tht the signl intensity in the review rticles pre-opertive T2 imge correltes with ptient ge, chronicity of the disese, nd post-opertive recovery. Ptients with greter signl intensity in T2 weighted imges recover poorly. Consequently, this prmeter my e used s predictor of surgicl prognosis (13). Mtsumoto et l. found no reltionship etween hyperintense signls nd prognosis (14). Tle 1. Etiologies Degenertive Compressive Trumtic Bone lesion Disc hernition Epidurl hemorrhge Infectious (scess) Tumors: Extrdurl: enign nd mlignnt Intrdurl: intr nd extr medullry Vsculr: rterio-venous mlformtion Syringomyeli Non-compressive Infectious trnsverse myelitis: Virl: Zoster, Estein-Brr, herpes simplex, cytomeglovirus, denovirus, enterovirus, Coxsckie B, type 6 herpes virus, HIV nd AIDS, HTLV I nd II Bcteril: stphylococcus ureus, streptococci, mycocteri Spirochetes: syphilis nd Lyme disese Fungi: cryptococcus, spergillus Acute Disseminted Encephlitis: Demyelinting diseses Multiple sclerosis Neuromyelitis optic Ele s disese Vsculr: Spinl rteril thromosis Centrl nervous system vsculitis (lupus, Sjögren s, srcoidosis) Toxic sustnces nd physicl gents Lthyrism, rsenic, tri-ortho-cresyl phosphte, nitric oxide nd intrthecl methotrexte Rdition Electric injury Degenertive: Primry lterl sclerosis Fmilil spstic prpresis Spinocereellr txi Iron neurodegenertion Friedriech s txi Metolic: Vitmin B12 deficiency Vitmin E deficiency Chronic heptic or renl disese Hexosmidse deficiency Prneoplstic Degenertive compressive myelopthy Degenertive compressive myelopthy my e clssified ccording to the compression site, s follows: Anterior (disc protrusion or posterior osteophytes). Anterolterl (Luschk joints). Lterl (fcet joints). Posterior (ligmentum flvum). Rev Colom Rdiol. 2011; 22:(3):1-21 3

4 It my e cused y tlnto-xil instility, spinl cnl stenosis due to cervicl spondylolysis (15), cervicl spinl fusion, myelomeningocele or epidurl msses. Atlnto-xil instility is the primry cuse of degenertive compressive myelopthy. It is found minly in rheumtoid rthritis, followed y Down s syndrome, Morquio s syndrome or type IV mucopolyscchridosis, skeletl dysplsi, nkylosing spondylitis nd Lesh-Nyhn syndrome (16). Ninety per cent of ptients with rheumtoid rthritis hve cervicl lesion, either n tlnto-xil suluxtion, tlnto-xil impction (silr invgintion), or Luschk joint disese, nd pnnus trnsfer to the disc or ligments. Neurologicl decline my e irreversile, lthough the lower cervicl spine is the most vulnerle to myelopthy (17) (Figure 1). Ptients with compressive myelopthy due to Morquio s syndrome hve cervicl disese due to tlnto-xil suluxtion, ssocited with hering loss, joint elsticity, growth retrdtion nd hip dysplsi (16) (Figure 2). On the other hnd, spinl cnl stenosis my e cused y fmilil pthologies such s chondroplsi or fmilil lumr stenosis, or y cquired diseses such s verterl collpse, nucleus pulposus hernition, spondylolysis or epidurl lipomtosis (18). Cnl stenosis secondry to nucleus pulposus hernition is more frequently found in C6-C7, ut it my occur in C5-C6 nd, to lesser extent, in C4-C5. It my e intrforminl nd produce sensory symptoms (most common), nterolterl with motor symptoms, or centrl with spinl cord compression resulting in myelopthy (18). Figure 1. Incresed intensity of the spinl cord in C2 in the T2 weighted sequence due to compressive myelopthy secondry to rheumtoid rthritis. Figure 2. Incresed intensity nd thickening of the spinl cord from the ulo-medullry junction down to C4 in the sgittl T2 sequence, due to compressive myelopthy in Morquio s syndrome. On MRI, there is usully hyperintense lesion in T2 weighted sequences close to the hernition re or the osteophyte tht is giving rise to spinl cord compression, lthough there my e extensive incresed intensity in T2 (more thn three segments), leding to the suspicion of n inflmmtory lesion. Gdolinium enhncement limited to the point of gretest stenosis, plus 4 history of progressive symptoms, contriute to the dignosis (6) (Figures 3 nd 3). Post-trumtic compressive myelopthy Post-trumtic myelopthy is four times more frequent in mles, in prticulr etween 16 nd 30 yers of ge. Motor vehicle cci- Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

5 dents re the most common cuse, ccounting for 50% of the events, followed y violence (firerm or st wounds), flls from heights, nd sports injuries (diving, Americn footll nd horseck-riding) review rticles (19). The most moile segments re more often ffected, in prticulr C5-C7 nd T10-L2. Cliniclly, qudriplegi predomintes in 30-40% of cses, nd prplegi occurs in 6-10% (16). Figure 3. ) Axil sequence with T2 grdient echo informtion. B) Sgittl section with T2 informtion in C7 showing diminished height nd signl intensity with nnulus protrusion in C5-C6 nd C6-C7; there is lso centrl nd left surticulr protrusion of the nnulus ssocited with nnulus nd ligment ter in C7, giving rise to centrl spinl hyperintensity due to compressive myelopthy resulting from nucleus pulposus hernition. MR imging is of vitl importnce in pproching spinl cord trum ecuse it shows loction, extension nd severity very clerly, nd lso revels edem nd intrmedullry leeding. Some studies hve shown tht hemorrhge nd longer hemtoms re ssocited with lower rte of motor recovery (20). Over the long term, CSF leks, infections, cysts nd syringomyeli my develop (16,21) (Figure 4). Ascess-relted compressive myelopthy Epidurl scesses re uncommon ut they constitute surgicl emergency ecuse they my progress rpidly within dys nd erly dignosis is difficult, leding to delyed tretment. The incidence is cses for every 10,000 hospitl dmissions. They ffect minly men, with no specific ge rnge (22), nd the incidence hs een shown to hve incresed in recent yers. Moridity nd mortlity re high, etween 18% nd 31%. Risk fctors re similr to those for spondylodiscitis, including dietes mellitus, use of intrvenous drugs, chronic renl filure, Figure 4. T2 weighted imge with nnulus protrusion in C4 nd C5, giving rise to spinl cord hyperintensity due to trumtic compressive myelopthy. Rev Colom Rdiol. 2011; 22:(3):1-21 5

6 lcohol use, nd immune deficiency. Lumr trum hs lso een descried in one third of ptients, s cuse for epidurl scess. Humn immunodeficiency virus hs not een shown to e the cuse of the incresed incidence (23). It usully presents s sucute lumr pin, fever (my e sent in sucute nd chronic stges), incresed locl tenderness, progressive rdiculopthy or myelopthy. The second phse of rdiculr irrittion is followed y neurologic deficit (muscle wekness, norml senstion nd incontinence) nd then y prlysis in 34% of cses, nd even deth. Symptoms result from mechnicl compression nd, in some cses, from ischemi. Any segment of the spinl cord my e ffected, ut the most frequent re the thorcic nd lumr segments. Numguchi et l. clssified the disese s focl when it involves up to five verterl segments, nd diffuse when it involves six or more (22). Stphylococcus ureus is the min pthogen found in 67% of cses, 15% of which involve the methicillin-resistnt strin (24). Mycocterium tuerculosis is the second most frequent pthogen, found in 25% of cses (22). The spinl cord culture is usully sterile most of the time (25). MRI is the dignostic method of choice, with sensitivity rnging etween 91% nd 100%. It must e selected s the first imging technique ecuse it is more sensitive thn other imging modlities nd llows to rule out other cuses. A spinl cord scess develops y phses, strting with n infectious myelitis tht ppers hyperintense on T2 with poorly defined enhncement, followed y lte phse with well-defined peripherl enhncement nd perilesionl edem. The finl phse is intrspinl scess formtion with low signl intensity in T1 imges nd high signl intensity in sequences with T2 informtion (25). Diffusion MRI my increse dignostic sensitivity nd specificity of spinl cord diseses (cute ischemi, tumors or multiple sclerosis lesion). However, it is not performed frequently ecuse of limittions such s movement rtifcts nd the smll size of the spinl cnl. Diffusion cn help with the detection of erly ischemic lesions, where conventionl MRI does not show normlities. On the other hnd, high-signl spinl res of reduced pprent diffusion coefficient re visile in ptients with spondylotic myelopthy, surrounded y low-signl hlo of edem. In cses of myelitis, there is only smll high-signl re tht llows to mke the distinction etween infection nd ischemi (26). Tsuchiy et l. used diffusion MRI to ssess fourteen ptients etween two hours nd three dys fter cervicl trum nd found tht lesions tht showed high signl on MRI with diffusion restriction showed myelomlci or excertion on follow-up, helping to predict the functionl prognosis (27). Tretment is emergency surgicl dringe nd decompression, plus rod-spectrum ntiiotics until the pthogen is isolted (23). The differentil dignosis includes extrdurl metstsis, epidurl hemtom, migrted disc frgments or epidurl lipomtosis (22) (Figures 5 nd 5). 6 Tumorl compressive myelopthy Myelopthy my e the initil mnifesttion of mlignncy in up to 20% of cses where the only systemic symptom is weight loss (16). Tumors compressing the spinl cord my e divided into extrdurl nd intrdurl. Extrdurl tumors my e clssified s follows: Benign: synovil cyst, osteom, osteolstom, gint cell tumor, hemngiom, eosinophilic grnulom, schwnnom nd meningiom. Mlignnt: one metstsis (re the cuse of the most common myelopthy due to extrdurl spinl cord compression) (28), multiple myelom, lymphom nd chondrosrcom. Intrdurl tumors re clssified s follows: Extrspinl: neurofirom, meningiom, lipom, schwnnom nd rchnoid cyst. Intrspinl: strocytom, ependymom, hemngiolstom nd metstsis. Forty per cent of ptients present with rdiculopthy nd myelopthy ssocited with sucute dorsl pin tht worsens in decuitus position. MRI my revel the cuse of the myelopthy nd help guide the pproch to the primry tumor (Figures 6 nd 7). Myelopthy of vsculr origin The rteril supply to the spinl cord consists of one nterior spinl rtery nd two posterior spinl rteries with their penetrting vessels. It is provided minly y the nterior spinl rtery tht emerges from the verterl rteries, the rtery of Admkiewicz (rteri rdiculrris mgn) of vrile origin, generlly left etween T9 nd T12, nd y nstomosis etween the nterior nd posterior spinl rteries, with hypovsculr re locted etween T4 nd T8. The spinl cord my e ffected y compressive nd non-compressive vsculr diseses, of which the most common re mlformtions of the durl rteriovenous fistul type (29). In cses of vsculr mlformtion, ptients present with non-specific clinicl findings, usully distl to the site of the disese. Erly detection nd tretment offer the est chnce for neurologicl recovery. These diseses were clssified y Riche in 1985 (29) s follows: Intrspinl rteriovenous mlformtions. Perispinl rteriovenous mlformtions. Spinodurl rteriovenous fistuls. Epidurl rteriovenous mlformtions. Prverterl vsculr mlformtions. Verterl hemngioms. Complex ngiomtosis (Co s syndrome, Osler-Weer- Rendu syndrome). Cvernoms, telngiectsis nd spinl venous ngioms (do not require endovsculr tretment). In 2002, Spetzler proposed the following new clssifiction (30): Neplstic vsculr lesions: hemngiolstom nd cvernous mlformtion. Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

7 review rticles Figure 5. ) Sgittl imge with T1 informtion showing signl-intensity chnges of the lower T10 endplte nd upper T11 endplte, nd of the corresponding disc, ssocited with hyperintensity nd spinl cord thickening in tht segment. ) Post-gdolinium STIR imge showing thickening of the preverterl soft tissues, the verterl odies nd the disc from T10 to T11. These enhnce with contrst, together with the thickened spinl cord due to myelopthy resulting from n epidurl scess. Spinl neurism. Arteriovenous fistul: extrdurl nd intrdurl. The ltter includes ventrl (smll, medium nd lrge) nd dorsl (one or severl feeding vessels) fistuls. Arteriovenous mlformtions: extr-intrdurl nd intrdurl (intrspinl, compct, diffuse nd of the medullry cone). Arteriovenous mlformtions my e durl or Type I (extrspinl, ccounting for 75%) (31). Ninety per cent re found in the low thorcic or lumr regions, nd in lesser proportion, in the scrl nd cervicl regions. They re four times more frequent in men, with men ge t onset of 58 yers. Initil symptoms include git disorders, presthesis or numness, lumr or rdiculr pin, symmetric wekness of the legs, nd leeding in up to 25% of cses. Arteriovenous fistuls my e differentited from other cuses of myelopthy ecuse symptoms re triggered y wlking or stnding for long periods of time (6). Eighty per cent present with ldder dysfunction, when the mlformtion involves the cone (32). The disese my progress over period of months nd even yers, nd my ecome excerted with exercise (33). Findings on MRI include serpent-like imges with sence of flow signls in most ptients; these structures pper enhnced in T1 imges with gdolinium (34). Intrspinl rteriovenous mlformtions ccount for 10% of cses nd include durl sinus dringe or Type II mlformtions, nd surchnoid venous dringe or Type III mlformtions. They re loclized in the cervicl spine in 46% of cses nd in the thorcolumr spine in 44% of cses. The ge of onset is under 40 yers, when hemorrhge is the min symptom, nd neurisms re present in 20% of cses. There is progressive myelopthy in up to 60% of cses. Cvernous mlformtions ccount for 5% of the 12% of spinl mlformtions nd re ssocited with leeding in 0.8% of cses. On MRI, they show intermedite signl in T1 nd T2, with presence of hemosiderin (Figures 8 nd 8). Another cuse of myelopthy of vsculr origin of the noncompressive type is cute vsculr occlusion, which is less frequent nd my led to n infrct tht mimics myelitis (8). Rev Colom Rdiol. 2011; 22:(3):1-21 7

8 Figure 7. Postgdolinium sgittl STIR imge showing spinl widening in C5 nd C6, with enhncement of the spinl cord nd the odies of C7 nd T1. There is lso enhncement of the preverterl soft tissues nd of the cervicl muscles due to myelopthy secondry to high-grde gliom. Figure 6. Post-gdolinium sgittl STIR imge showing norml signl intensity of the odies of T3 nd T4, with pthologicl frcture of T3 involving the epidurl component nd which compresses the spinl cord. There is gdolinium enhncement of T1, T3 nd T4 nd of the spinous processes, ut no enhncement of the spinl cord due to metsttic disese. This cuses tumor compression myelopthy. The dignosis of myelopthy secondry to spinl cord ischemi is difficult ecuse of the lck of dignostic criteri in the cute stge. It hs een found generlly in ptients over 50 yers of ge (9,35). The initil symptoms usully present within less thn four hours nd include severe motor nd sphincter dysfunction, temperture nd pin ltertions, with no ltertions to virtion or proprioception. The etiologies include the following: Arteril thromosis: ortic surgery, spinl ngiogrphy, vsculitis, emolism, rteril dissection, hypotension, nd prothromotic sttes. Anterior spinl rtery lesion: nterior spinl syndrome Posterior spinl rtery lesion: posterior column syndrome Sucommisurl rtery lesion: Brown Séqurd syndrome Arteriovenous fistul 8 Venous infrct CSF is norml, lthough in rteriovenous fistuls there my e higher protein concentrtions without pleocytosis (8). Spinl MRI shows single centrl hyperintensity. The CSF nlysis revels sent or low cell content, without oligoclonl nds (Figure 9). Compressive myelopthy due to syringomyeli Syringomyeli is rre neurologic disorder, chrcterized y the slow development of fluid-filled res extending long the spinl cord, nd cusing symptoms such s pin, wekness nd stiffness of the ck, shoulders nd lims. The prevlence is 3.3 to 8.5 cses for every 100,000 people nd it vries depending on the ethnic ckground. In the United Sttes, it is more common mong Africn-Americns. It my e relted to congenitl or cquired mlformtions. Chiri s mlformtion is congenitl normlity in which cereellr mygdls hernite through the formen mgnum in the spinl cnl, with ltered CSF flow. This cuses hedche, doule vision, dizziness nd muscle wekness of the upper lims. Most non-trumtic forms of syringomyeli re due to Chiri mlformtion (36,37). The cquired cuses of syringomyeli include trum, tuerculosis-ssocited chronic rchnoiditis, nd intrspinl tumors (38) (Figures 10 nd 10). Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

9 review rticles Figure 8. ) Sgittl sequence with T2 informtion of the medullry cone, showing serpentlike, tortuous intr nd extrspinl imges with sence of flow signl, ssocited with dorsl spine hyperintensity. ) Arteriogrm confirming the presence of durl rteriovenous mlformtion with myelopthy of vsculr origin. Figure 9. Fifteen-yer old ptient with neurologic deficit of sudden onset nd norml lortory tests. The sgittl sequence with T2 informtion shows high-intensity signl nterior to the spinl cord suggesting dignosis of myelopthy due to ischemi. Rev Colom Rdiol. 2011; 22:(3):1-21 9

10 Non-compressive myelopthies Once compression is ruled out s the etiology of myelopthy, the clinicl history is nlyzed in depth nd creful clinicl exmintion is performed in order to look for n inflmmtory cuse. The dignosis of n inflmmtory myelopthy requires evidence of spinl cord inflmmtion. At the present time, MRI nd CSF nlysis re the only tools ville for determining the presence of inflmmtion. There needs to e gdolinium enhncement of the spinl cord, pleocytosis in the CSF or high immunogloulin G index in the CSF, with time course rnging etween four hours nd four weeks. If none of these findings re present t the time of onset of symptoms, MRI nd lumr tps must e repeted two to seven dys lter (39). Trnsverse myelitis Acute trnsverse myelitis is spinl disorder chrcterized y ilterl motor, sensory nd utonomic normlities ecuse it involves the spinothlmic nd pyrmidl trcts, the poste- Figure 10. ) Sgittl sequence with T2 informtion of the cervicl spine showing Chiri mlformtion type II, sent corpus cllosum nd tuulr zone of high signl intensity in the spinl cord down from the ulo-medullry junction, involving ll the segments. ) Sgittl sequence with T2 informtion of the dorso-lumr spine with myelopthy secondry to syringomyeli. rior columns nd the nterior funiculus of one or more levels (25). Close to one third of the ptients recover with mild or no sequele, one third hve mild degree of disility, nd yet nother third hve serious disility. Middle-ged dults re most frequently ffected. A puliction estlished the following criteri for trnsverse myelopthy: ilterl spinl cord dysfunction during four-week 10 period with well-defined sensory level nd no history of disese, where compression hs een ruled out. Other criteri re proposed lter for the differentition etween inflmmtory nd non-inflmmtory trnsverse myelitis, nd etween idiopthic trnsverse myelitis nd myelitis ssocited with systemic or nervous system disese. These criteri re the following (5): Sensory, motor or utonomic dysfunction of spinl origin. Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

11 Bilterl signs nd symptoms. Clerly defined sensory level. Spinl inflmmtion (CSF pleocytosis or high immunogloulin G levels, or gdolinium enhncement). Mximum progression during period rnging etween four hours nd four weeks. In 2002, the Trnsverse Myelitis Consortium Working Group proposed CSF nd MRI criteri for the dignosis of idiopthic trnsverse myelitis, including the following: 1) spinl ilterl motor, sensory or utonomic dysfunction; 2) ilterl sensory level signs nd symptoms; 3) evidence of spinl inflmmtion on MRI or CSF tests; 4) symptoms with durtion rnging etween few hours nd 21 dys, from onset to mximum deficit; nd 5) extr-xil compression ruled out (40). In cute cses, the histopthology shows medullry nd perivsculr focl infiltrtion of monocytes nd lymphocytes with strogli nd microgli ctivtion. In sucute phses, the finding is mcrophge infiltrtion (5). MRI findings include focl nd centrl high signl res in T2 sequences, occupying more thn two thirds of the spinl cord xilly, nd extending over three to four segments, generlly in the thorcic spine. Spinl expnsion my or my not e found nd, in generl, review rticles there is contrst medium enhncement, usully ptch-like or diffuse. MRI findings re usully norml in 40% of cses. There is growing evidence tht the length of the lesion my e importnt from prognostic stndpoint. Lesions extending less thn two segments involve the risk of developing MS (40) (Figures 11 nd 11). Inflmmtory trnsverse myelitis, in the sence of specific cuse (idiopthic), is the min cuse of cute myelitis. It vries significntly in frequency (from 9% to 60% ccording to some studies) (9). There re two incidence peks the first etween 10 nd 19 yers of ge, nd the second etween 30 nd 39 (8). The dignosis is mde y exclusion nd it hs course of progression etween four hours nd four weeks. Clinicl nd MRI follow-up of these ptients hs led to dignosis in pproximtely 50% of cses (9). The ility to differentite trnsverse myelitis from other intrmedullry diseses, in prticulr spinl tumors, is criticlly importnt ecuse it my help differentite etween surgery, post-opertive complictions nd rdiotherpy. The use of gdolinium hs mde it possile to detect spinl tumors nd delimit their loction nd extension in reltion to the perilesionl edem (41) (Figure 12). Figure 11. Twenty-yer old ptient with suspected multiple sclerosis. ) The sgittl sequence with T1 informtion shows widening of the spinl cord from C3 down to C7, with no other norml findings. ) Centrl high-signl re in T2 sequences due to cute trnsverse myelopthy. Rev Colom Rdiol. 2011; 22:(3):

12 Figure 12. Sixty-one-yer-old femle ptient with neurologicl normlities over the pst three dys, ut no significnt history. Lortory tests nd the medullry iopsy were ll norml. The sgittl sequence with T2 informtion showed discl nd osteophytic chnges of the verterl odies ssocited with ulging of the inferior nnulus nd thickening nd hypersensitivity of the cervicl spinl cord from the crniocervicl junction down to C7. The clinicl findings nd the dditionl studies estlished the dignosis of idiopthic myelopthy. Prinfectious myelopthy Neurologicl dmge in prinfectious myelopthy is cused directly y the infection, the immune rection ginst the gent, nd the rection of the immune system. It is usully due to lood-orne infection originting in the lungs, the skin, the skeletl, genitourinry or digestive systems. It presents with severe motor nd sphincter dysfunction ssocited with fever, meningism nd skin exnthem. The time period for the onset of myelitis fter the infection is no different etween infectious nd post-infectious myelitis: five dys for smll-pox myelitis, ten dys for mycoplsm nd twelve dys for herpes zoster myelitis (43,44). Possile etiologies include the following (3): Virl: herpes, vricell zoster, EBV, CMV, HIV, dengue, influenz, mesles, mumps, HTLV-1, enterovirus, Coxsckie B, heptitis A nd C, nd polio. Bcteril: mycoplsm, treponem pllidum, rucell, mycocterium tuerculosis nd orreli. 12 Fungi: ctinomyces, lstomyces, coccydiodes nd spergillus. Prsites: schistosom, cysticercus, echinococcus nd toxoplsm. There is CSF pleocytosis, generlly neutrophili with incresed protein concentrtions nd no oligoclonl nding (8). Spinl MRI findings include extensive centrl high signl res in T2 sequences, ssocited with spinl edem, minly cervicodorsl. Brin MRI is usully norml; however, normlities hve een descried, including white mtter chnges very similr to those found with cute demyelinting encephlopthy. Syphilitic myelopthy is rre mnifesttion of neurosyphilis. It ppers s high-signl imge in T2 sequences, with enhncement minly on the spinl surfce tht disppers, suggesting its reversile nture. Intrspinl tuerculosis is rre. Intrspinl tuerculoms re found in 0.002% of cses of tuerculosis, nd in 0.2% of cses of CNS tuerculosis. MRI is the method of choice for detecting spinl tuerculoms. Fusiform spinl edem is found, with res of intermedite or high signl intensity in T1 sequences. In T2 sequences there re centrl low signl res with surrounding edem. A high-signl center in T2 my e present due to the lower degree of cseifiction or liquefction. The solid or ring enhncement is present in contrst imges (40) (Figures 13 nd 14). Acute disseminted encephlomyelitis Acute disseminted encephlomyelitis (ADEM) is n uncommon inflmmtory disese of the centrl nervous system, chrcterized y diffuse demyelintion of the cererl white mtter nd the spinl cord. It is more frequent in children nd young dults. It hs een ssocited with infection or vccintion, ut this is not considered criterion in clinicl consensus (45). It is elieved to e single-phse disese with good prognosis; however, recurrent forms mke differentition from MS difficult (22). ADEM hs clinicl mnifesttions tht usully include encephlopthy ut my lso include focl or multifocl demyelinting inflmmtory syndromes of the CNS such s optic neuritis nd myelitis. For tht reson, ADEM is differentil dignosis for isolted demyelinting syndrome, which is more common precursor of MS in dults (45). ADEM symptoms include rpidly progressing encephlopthy ssocited with seizures or multiple neurologic deficits. The spinl cord is ffected in 11% to 28% of ptients, generlly in the thorcic nd cervicl segments. CSF findings re non-specific nd oligoclonl nds re found in 65% of ptients (8). MRI shows ilterl symmetric multifocl white mtter lesions, with or without dmge of the grey mtter, nd extensive disese of severl spinl segments with expnsion. These lesions pper with low signl in T1 sequences, nd well defined with high signl in T2 sequences; gdolinium enhncement is vrile. All ptients with spinl involvement hve rin dmge (8,22). These findings do not differentite it from MS; the only chrcteristics tht help with the differentition re the singlephse occurrence nd the complete spinl cord involvement Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

13 review rticles Figure 13. ) Sgittl sequence with T1 informtion showing thickening of the spinl cord from the crniocervicl junction down to the thorcic region. ) Sgittl sequence with T2 weighted imge showing high centrl spinl signl. HTLV-1 infection is confirmed lter y positive serology. in ADEM. ADEM differentition from MS nd neuromyelitis optic is importnt for prognosis nd tretment, ecuse ptients with MS nd neuromyelitis optic enefit from erly tretment s wy to void relpses. Up to 35% develop MS in the course of follow-up (22). There re no dignostic criteri, ut ADEM must e suspected when one or more of the following re present (45): Initil multifocl presenttion with multiple symptoms. Less thn 10 yers of ge. Signs nd symptoms of meningoencephlitis. Encephlopthy. Bilterl optic neuritis. CSF pleocytosis without oligoclonl nding. MRI shows lesions in res not ffected y MS, such s the grey mtter or the cortex. Lesions on MRI pper lrger with poorly defined edges tht enhnce with gdolinium. Advnced neuroimging such s diffusion tensor nd mgnetiztion trnsfer imging my help identify the involvement of the pprently norml white mtter, which is norml in MS nd norml in ADEM (45) (Figure 15). Myelopthies due to demyelinting diseses The onset of neurologic symptoms occurs over period of dys s result of demyelintion, lthough necrotizing myelopthies, like neuromyelitis optic, my sometimes progress in mtter of hours. They usully occur in ptients with prior non-specific virl infection (8). Multiple sclerosis MS is chronic demyelinting inflmmtory CNS disese. It is common in Europe, the United Sttes, Cnd, New Zelnd nd Austrli, ut it is rre in Asi, the tropics nd the sutropicl regions. It is estimted to ffect etween 250,000 nd 350,000 individuls in the United Sttes nd more thn 2,500,000 in the world (40,46). In high-risk popultions, the incidence is one out of every 200 women. The femle-to-mle rtio vries etween 1.5 nd 2.5. The ge of onset of symptoms vries y region; however the incidence is low in children, increses in dolescence nd peks etween 25 nd 35 yers of ge, fter which it strts to decline (47). The etiology remins unknown, lthough Rev Colom Rdiol. 2011; 22:(3):

14 Figure 14. Twenty-four-yer old ptient with congenitl HIV nd tuerculosis. The imge shows ltertion in the shpe nd signl intensity of the verterl odies of T10 nd T11, of the disc nd of the preverterl soft tissues. It is ssocited with widening of the spinl cord with edem nd contrst enhncement, nd with fluid ccumultions ner the spinl cnl in the post-gdolinium sgittl STIR sequence due to tuerculous myelopthy. 14 Figure 15. Twenty-eight-yer old ptient presenting with sudden neurologic decline. ) Coronl FLAIR sequence of the rin showing hyperintensity in the ulo-medullry junction. ) Axil imge with T2 informtion in the ulo-medullry junction with nterior hyperintensity relted to myelopthy due to cute disseminted encephlopthy. environmentl, virl nd immune-medited fctors in geneticlly susceptile ptients re thought to e the culprits (40,46). The strongest risk fctor is fmily history. Approximtely 80-85% of ptients present with relpsing picture, with symptoms tht lst for severl dys nd improve over the course of weeks. In 15% of ptients, the disese is progressive from the strt (40,46). It is the most studied of ll cute myelopthies, nd its effects rnge from irreversile tissue loss to prtil demyelintion where there cn e remyelintion nd repir (40). There is spinl cord involvement in more thn 90% of ptients. It my present in the form cervicodorsl symmetric trnsverse myelitis with sensory symptoms. Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

15 On MRI, lesions re low signl in T1 sequences nd high signl in T2 sequences, nd they re visile in 95% of ptients, generlly in the cervicl spine, nd on occsions they show gdolinium enhncement, even in symptomtic ptients (48). Lesions my e focl, diffuse with xonl loss, nd spinl trophy. Focl lesions re peripherl, symmetricl nd my involve from few millimeters up to couple verterl segments. They loclize to the posterolterl region of the spinl cord. On the sgittl plne, the plques my e nterior, centrl or posterior. Acute lesions enhnce with gdolinium, due to rupture of the lood-rin rrier. This enhncement is less in cererl lesions. Unlike neuromyelitis optic, virl or idiopthic myelitis, in MS no lck holes re visulized in the spinl cord (40, 46). Diffuse lesions re more frequent in primry MS, nd they pper s slightly higher intrspinl signl in T2 sequences. It hs een shown tht 70% of chronic lesions present with xonl loss. NAA hs een found to e reduced on spectroscopy, in spinl cord res tht pper norml on conventionl MRI (40). A reltionship hs een found etween low-signl lesions in T1 sequences nd the degree of disility, wheres no ssocition hs een found etween high-signl nd enhncing lesions in T2 sequences. This dissocition etween MRI nd clinicl disility hs prompted the serch for other mrkers tht my provide informtion out the nturl history of the clinicl compromise (48). Polmn et l. reviewed McDonld s dignostic criteri in 2010 nd proposed the following (49): Spce: one or more lesions with nd without gdolinium enhncement in two of the following res: periventriculr, juxtcorticl, infrtentoril, or the spinl cord. Time: one new lesion on T2 sequences or gdoliniumenhncing lesion when compred to the previous MR imge, nd concomitnt finding of symptomtic lesions with or without enhncement. The following criteri re defined for MS with progression from the strt (49): One yer of disese progression, plus two of the following: evidence of one or more rin lesions in T2 review rticles sequences, with or without enhncement in two of the chrcteristic sites (periventriculr, juxtcorticl or infrtentoril); evidence of two or more spinl cord lesions in T2 sequences with or without enhncement; nd positive CSF (oligoclonl nds or elevted immunogloulin G index). The CSF nlysis shows oligoclonl nds in up to 90% of cses. During the initil phses of MS, efore the development of glil scrs, symptoms resolve over period of weeks or months. Cererl MRI shows concomitnt demyelinting lesions; the presence of two or more lesions is ssocited with n 88% proility of conversion to sclerosis within the following twenty yers. When the MRI is norml, this risk is only 19% (8). Anorml evoked potentils do not help differentite etween multiple sclerosis nd myelitis due to systemic disese (Figure 16). Neuromyelitis optic or Devic s syndrome Neuromyelitis optic is defined s the concomitnt presenttion of myelitis nd optic neuritis. This comintion occurs in MS, ADEM, systemic lupus erythemtosus nd Sjögren s syndrome. It is lso found in ssocition with virl nd cteril infections (50). Neuromyelitis optic is n immune CNS demyelinting condition tht ffects the spinl cord nd the optic nerves. It is often mistken with MS, lthough clinicl, rdiologicl nd immunopthologicl tests suggest tht they re different. The identifiction of the specific ntigen of the neuromyelitis optic immunogloulin G/quporin 4 ntiody implies humorl immunity, which mkes it different from MS (51). It is n uncommon disorder mong the Western popultion, with n incidence of 0.4 per million people per yer, representing one out of every 200 ptients with demyelinting disese. In Asi, the Crien nd South Americ, the incidence is higher, pointing to genetic mechnisms. In ll popultions, femles with men ge of 40 re predominntly ffected, in 3:1 rtio (51). It is usully recurrent (8). Figure 16. Twenty-eight-yer old ptient dignosed with multiple sclerosis in Decemer 2010 with progression in time nd spce. ) Sgittl sequence with T2 informtion showing high spinl signl in C4. ) High-signl re in C4 shown on T2 grdient echo xil view due to myelopthy secondry to multiple sclerosis. Rev Colom Rdiol. 2011; 22:(3):

16 The clinicl findings, which my e present t the sme time or seprted y severl yers, re trnsverse myelitis with longitudinl extension nd optic neuritis. Optic neuritis my e unilterl or ilterl. Up to 80% of ptients will experience recurrences, which re usully more deilitting thn in ptients with typicl MS. Dignostic criteri (8,51) include optic neuritis nd cute myelitis, nd t lest two of the following: Centrl spinl lesions on MRI in more thn three verterl segments. MRI findings non-consistent with MS. Immunoglouline G-positive neuromyelitis optic (S70% nd E>90%). CSF findings of pleocytosis, elevted proteins nd lumin, with no evidence of oligoclonl nds (8). Rdiologicl chrcteristics include centrl longitudinl nd extensive cervicodorsl lesion (three or more spinl segments) with spinl expnsion, of low signl in T1 sequences nd high signl in T2 sequences nd ptchy enhncement. Lesions of the optic nerves re found on occsions (50). Although the clssicl thinking ws tht neuromyelitis optic ws not ccompnied y rin lesions, it hs een demonstrted tht 60% of ptients my hve periventriculr lesions (res of high quporin 4 concentrtion, trget for neuromyelitis optic-immunogloulin G) (8). MRI my help differentite etween neuromyelitis optic nd MS. In this cse, neuromyelitis optic is not ssocited with cererl white mtter lesions, nd the spinl lesions re confluent nd extend to multiple segments (which is infrequent in MS); moreover, crnil nerve nd cereellr involvement is common in MS nd is not present in neuromyelitis optic (21). Recovery from neuromyelitis optic is less complete. Pulished studies suggest 68% five-yer survivl, with mortlity resulting from severe spinl compromise nd respirtory filure (51). The presence of the neuromyelitis optic-immunogloulin G ntiody predicts the risk of developing recurrent myelitis. Certin utoimmune conditions my coexist with neuromyelitis optic, including systemic lupus erythemtosus, Sjögren s syndrome nd utoimmune thyroid disese (Figure 17). Myelopthy due to systemic disese Myelitis ssocited with systemic disese hs een rrely descried in the literture. It hs een ssocited with systemic lupus erythemtosus (SLE), Sjögren s syndrome, scleroderm, Behçet disese, nd srcoidosis (25). It hs een estimted tht the frequency of myelitis in ptients with SLE is 3%, ut it is unknown in Sjögren s syndrome. Myelitis usully occurs in the first yer of the disese nd my e its first mnifesttion. The hypothesis out the pthophysiology is still suject for dete, nd the most ccepted is vsculr mechnism secondry to ischemic lesions (9). Women re more frequently ffected thn men, in n 8:1 rtio. CNS involvement in SLE is often found in reltion with the ntiphospholipid syndrome with nticrdiolipin ntiodies (22). The clinicl symptoms often include trnsverse myelitis with severe motor nd sensory dysfunction. CSF my e norml or show plecytosis, nd lthough oligoclonl nds re rre, they my e present (9). MRI findings hve een studied more in SLE thn in Sjögren s syndrome. Moreover, it hs een found tht the centrl high-signl spinl lesion in T2 sequences, oc- 16 Figure 17. Forty-four-yer old ptient with demyelinting disese nd proven neurologicl decline. ) Diminished signl intensity in the upper segments of the cervicl spinl cord in the sgittl T1 sequence. ) Sgittl sequence with T2 informtion showing hyperintensity from the ulo-medullry junction down to C6 nd C7, due to neuromyelitis optic myelopthy. Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

17 cupying two-thirds of the spinl cord in xil sections, extends over three or four segments nd shows vrile gdolinium enhncement (22,25). Norml or mild res of high signl hve een descried on MRI. In Sjögren s syndrome, spinl MRI hs een studied only in isolted cses, nd findings re similr to those of SLE (25) (Figure 18). CNS srcoidosis my occur in isoltion in the form of myelopthy. The definitive dignosis requires iopsy evidence of non-cseifying grnulomtous inflmmtion of the CNS or ny other compromised orgn. Angiotensin-converting enzyme elevtion is suggestive of the dignosis ut is not specific. An isolted CNS srcoidosis must e suspected when slowlyprogressing sucute myelopthy is present, with symmetricl spinl cord ptches nd persistent gdolinium enhncement. review rticles A stisfctory response to empiricl steroid tretment, during months or even yers, suggests the dignosis (6). Post-rdition or electric dmge Neurotoxicity is known compliction of high-dose rdition. The deep white mtter is the most ffected since it comprises the cortex nd the sucorticl rcute fiers. There re three forms of lesions: cute (weeks or months), erly lte nd lte (six months to two yers). The ltter my e irreversile, progressive nd, on occsions, ftl; however, it my resolve spontneously in some cses (52,53). Rdition myelopthy is devstting compliction of rdition therpy (22). It is rre cuse of cute myelopthy, ccounting for only 2% of complictions, nd it is suggested in cses where there is history of exposure to hed nd neck Figure 18. ) Sgittl sequence with T2 informtion showing spinl cord thickening nd hyperintensity from C4 down to T2. ) Post-gdolinium STIR imge showing enhncement due to SLE-ssocited myelopthy. rdition (even longer thn ten yers), with dose greter thn 4,000 rds. It is n irreversile process with no effective tretment (52). It my hve n erly mnifesttion ten to sixteen weeks into rdiotherpy, or lte mnifesttion, nd my resolve spontneously etween two nd nine months fter onset (9). In the erly stges, there is evidence of edem or spinl enhncement nd, in lte cses, spinl trophy is oserved (8). It mnifests s trnsient sensory loss, progressive chronic myelopthy, cute trnsverse myelitis, or locl myotrophy. The trnsient sensory loss gives n electric-shock senstion when the neck is flexed forwrd (Lhermitte sign) nd it resolves within two nd thirty-six weeks. In chronic progressive myelopthy, it presents like Brown Séqurd syndrome lsting etween three months nd five yers. Rev Colom Rdiol. 2011; 22:(3):

18 The CSF nlysis is norml in most cses, with sent oligoclonl nding. There is no cellulr rection nd this is how in my e differentited from MS (8). Spinl cord MRI shows high signl imge in T2 sequences, with locl spinl edem nd gdolinium enhncement, during t lest eight months. After this time, the signl intensity is norml nd there is severe trophy, with or without persistent enhncement tht diminishes fter 24 months (22) (Figure 19). Figure 19. Ptient with history of rdiotherpy due to esophgel cncer who complins of presthesis nd discreet loss of strength in the lower lims, nd Lhermitte sign. ) Sgittl T2 imge of the dorsl spine with discreet fusiform thickening of the spinl cord showing high intensity signl nd post-rdiotherpy one mrrow chnges. ) Follow-up MRI fter 18 months with evidence of prtil regression of postrdition myelopthy. Courtesy of Dr. Alex Rovir Cñells, Hed of the Mgnetic Resonnce Unit t Vll d Heron University Hospitl. Sucute comined degenertion Comined sucute degenertion is compliction of vitmin B12 deficiency, ssocited with pernicious nemi. This deficiency my e relted to prietl-cell utontiodies or the intrinsic fctor required for vitmin B12 inding. There is genetic deficiency of trnscolmin 2 (colmin trnsporter protein). The complete trnscolmin 2 deficiency is recessive utosoml condition chrcterized y norml concentrtions of vitmin B12 with severe infntile meglolstic nemi ssocited with neurologic dmge (54). The clinicl picture presents s slowly-progressing spstic prpresis with distl proprioceptive loss nd symmetricl dysesthesis (54). This clinicl picture is due to xonl loss nd inferior cervicl nd thorcic spinl demyelintion, generlly in the posterior nd nterolterl columns, tht cnnot e explined y compression or inflmmtion on MRI (22,25,54). The sence of nemi with or without mcrocytosis does not rule out vitmin B12 deficiency dignosis. MRI shows high signl intensity of the posterior columns in T2 sequences, without contrst enhncement (25). Imging improvement correltes with clinicl improvement (22). The men time to dignosis since the onset of neurologicl symptoms due to vitmin B12 deficiency is pproximtely on yer, with rnge tht extends to four yers (54) (Figure 20). Acute prneoplstic or necrotizing myelitis Prneoplstic myelopthy is rre disese. It my occur efore the cncer is detected. Severl ntiodies hve een ssocited with sucute myelopthies, in generl with lung, rest, thyroid, ovrin nd prostte cncer, nd Hodgkin s lymphom. The lesion often involves the thorcic spinl cord tht shows high-intensity signl in T2 sequences nd gdolinium enhncement. There is incresed protein concentrtion in the CSF (8). Myelopthy with norml MRI In some cses of cute myelopthy, the MR imge is norml. There re severl explntions for this: 1) the syndrome is not myelopthy (Guillin-Brré, inflmmtory rdiculopthy); 2) the picture my not e cute ut rther decompensted existing myelopthy (Friedreich s txi, motor neuron disese, vitmin B12 deficiency, HIV or HTLV-1 myelopthy); nd 3) MRI performed during the convlescence period (8) (Figure 21). 18 Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A

19 review rticles c d Figure 20. ) Sgittl T2 sequence showing hyperintense signl in the dorsl spine. ) Axil T2 imge confirming spinl dmge predominntly in the posterior horns. Low concentrtions of vitmin B12 were found, pointing to the dignosis of myelopthy due to vitmin B12 deficiency. c) nd d) Follow-up MRI performed one yer fter the dignosis, showing no evidence of normlities. Courtesy of Dr. Alex Rovir Cñells, Hed of the Mgnetic Resonnce Unit t Vll d Heron University Hospitl. Neurologicl dysfunction consistent with spinl cord lesion Confirm cute myelopthy Determine deficit time Signs nd symptoms, or history suggesting infection, inflmmtory disese, vsculr disese, neoplsm, MS, exposure to rdition, or trum Determine whether there is history of vccintion or trum Step I: Rule out compression with contrst MRI of the spinl cord Consider non-inflmmtory cuses: Ischemi, rdition, epidurl lipomtosis, emolism Consider erly myelopthy (repet studies in 7 dys) Step II: Define the presence of spinl cord inflmmtion y mens of lumr tp Step III: Define site nd extent of demyelintion y mens of contrst rin MRI nd evoked potentils Demyelintion site Brin/rin nd optic trcts nd spinl cord Multiple sclerosis ADEM Spinl cord Trnsverse myelitis Optic trct nd spinl cord Neuromyelitis optic (Devic) Figure 21. Digrm of the dignostic pproch to myelopthies. Rev Colom Rdiol. 2011; 22:(3):

20 Acknowledgements We re grteful to Dr. Alex Rovir Cñells, Hed of the Mgnetic Resonnce Unit t Vll d Heron University Hospitl. References 1. Myelopthy. Diseses Dtse Ver 1.8. Medicl lists nd links [internet] [citdo: 2 de julio del 2011]. Disponile en: sp?glnguserchoice= Huser SL. Diseses of the spinl cord. En: Hrrison s principles of internl medicine. 16 th ed. New York: McGrw-Hill; p Grcí DR. Mieloptís. Mnul de Práctics Médics-Hospitl Hermnos Ameijeirs [internet] [citdo: 18 de junio del 2011]. Disponile en: 4. Scotti G, Gerevini S. Dignosis nd differentil dignosis of cute trnsverse myelopthy. The role of neurordiologicl investigtions nd review of the literture. Neurol Sci. 2001;22Suppl 2:S Kplin AI, Krishnn C, Deshpnde DM, et l. Dignosis nd mngement of cute myelopthies. Neurologist. 2005;11: Schmlstieg WF, Weinshenker BG. Approch to cute or sucute myelopthy. Neurology. 2010;75:(18 Suppl 1):S Ghezzi A Bldini SM, Zffroni M. Differentil dignosis of cute myelopthies. Neurol Sci. 2001;22(Suppl 2):S Jco A, Weinshenker BG. An pproch to the dignosis of cute trnsverse myelitis. Semin Neurol. 2008;28: De Seze J, Stojkovic T, Breteu G, et l. Acute myelopthies: Clinicl, lortory nd outcome profiles in 79 cses. Brin. 2001;124: Wong SH, Boggild M, Enevoldson TP, et l. Myelopthy ut norml MRI: where next? Prct Neurol. 2008;8: Moore AP, Blumhrdt LD. A prospective survey of the cuses of non-trumtic spstic prpresis nd tetrpresis in 585 ptients. Spinl Cord. 1997;35: Kelley BJ, Erickson BJ, Weinshenker BG. Compressive myelopthy mimicking trnsverse myelitis. Neurologist. 2010;16: Yukw Y, Kto F, Yoshihr H, et l. MR T2 imge clssifiction in cervicl compression myelopthy: predictor of surgicl outcomes. Spine. 2007;32: Mtsumoto M, Toym Y, Ishikw M, et l. Incresed signl intensity of the spinl cord on mgnetic resonnce imges in cervicl compressive myelopthy. Does it predict the outcome of conservtive tretment? Spine. 2000;25: Montgomery DM, Brower RS. Cervicl spondylotic myelopthy. Clinicl syndrome nd nturl history. Orthop Clin North Am. 1992;23: Neuromusculr [internet] [citdo: 18 de junio del 2011]. Disponile en: html Clifford R. Wheeless textook of orthopedics [internet] [citdo: 7 de noviemre del 2010]. Disponile en: wheelessonline.com/ortho/cervicl_spine_in_r. 18. Clifford R. Wheeless textook of orthopedics [internet] [citdo: 2 de noviemre del 2010]. Disponile en: wheelessonline.com/ortho/cervicl_disc_hernition. 19. Sekhon LH, Fehlings MG. Epidemiology, demogrphics, nd pthophysiology of cute spinl cord injury. Spine. 2001;26(24 Suppl):S Leypold BG, Flnders AE, Burns AS. The erly evolution of spinl cord lesions on MR imging following trumtic spinl cord injury. AJNR Am J Neurordiol. 2008;29: Potter K, Sifuddin A. Pictoril review: MRI of chronic spinl cord injury. Br J Rdiol. 2003;76: DeSnto J, Ross JS. Spine infection/inflmmtion. Rdiol Clin North Am. 2011;49: Berger JR, Set A. Infectious myelopthies. Semin Neurol. 2002;22: Drouiche RO. Spinl epidurl scess. N Engl J Med. 2006;355: l Dee SM, Yqu BA, Bruyn GW, et l. Acute trnsverse myelitis. A loclized form of postinfectious encephlomyelitis. Brin. 1997;120: Bmmer R, Fzeks F, Augustin M, et l. Diffusion-weighted MR imging of the spinl cord. AJNR Am J Neurordiol. 2000;21: Tsuchiy K, Fujikw A, Hony K, et l. Vlue of diffusionweighted MR imging in cute cervicl cord injury s predictor of outcome. Neurordiology. 2006;48: Helweg-Lrsen S, Sorensen PS. Symptoms nd signs in metsttic spinl cord compression: study of progression from first symptom until dignosis in 153 ptients. Eur J Cncer. 1994;30A: Crgine LP Jr, Hlch VV, Ng PP, et l. Vsculr myelopthiesvsculr mlformtions of the spinl cord: presenttion nd endovsculr surgicl mngement. Semin Neurol. 2002;22: Spetzler RF, Detwiler PW, Riin HA, et l. Modified clssifiction of spinl cord vsculr lesions. J Neurosurg. 2002;96(2 Suppl): Riche MC, Reizine D, Melki JP, et l. Clssifiction of spinl cord vsculr mlformtions. Rdit Med. 1985;3: Bempord JA, Sze GS. MR imging of spinl cord vsculr mlformtions with n emphsis on the cervicl spine. Mgn Reson Imging Clin N Am. 2000;8: Jellem K, Cnt LR, Tijssen CC, et l. Spinl durl rteriovenous fistuls: clinicl fetures in 80 ptients. J Neurol Neurosurg Psychitry. 2003;74: Strom RG, Derdeyn CP, Morn CJ, et l. Frequency of spinl rteriovenous mlformtions in ptients with unexplined myelopthy. Neurology. 2006;66: Msson C, Pruvo JP, Meder JF, et l. Spinl cord infrction: clinicl nd mgnetic resonnce imging findings nd short term outcome. J Neurol Neurosurg Psychitry. 2004;75: Wlid MS, Snouf M, Slvtierr J. Syringomyeli: compliction of n underlying pthology. J Clin Med Res. 2010;2: Dignostic pproch to myelopthies. Grndos A; Grcí L; Orteg C; López A