POTT SDISEASE: ARadiologicalReviewof

Tuberculous

Spondylitis

StellaSafo

GillianLieberman,MD

April2009

HarvardMedicalSchool

BethIsraelDeaconessMedicalCenter

Agenda1.Explaintheevaluation,diagnosisand

treatment

of

spinaltuberculosis.

2.Reviewfeaturesofspinaltuberculosisonradiographs,CT andMRI.

3.FocusonthediagnosisofspinalTBusingradiographs,as thisistheprimarymodalityavailableinmanyresource

limitedsettingswherespinalTBisendemic.

OurPatient:InitialPresentation

A40yearoldhealthyKenyanwoman,MsB.G,presentedtoherPCP

witha1yrhistoryoflowbackpain(LBP)

thatbeganafterafall.

Sharp,unremittingpainexacerbatedbymovement,withoutradiculopathy

Physicalexamwasunremarkable

MinimalreliefwithNSAIDSandphysicaltherapy

Shebecamepregnant

threemonthslater.

LBPcontinuedandworsenedthroughoutpregnancy

Postpartum

Developedbilateralanteriorthighparesthesias

exacerbatedbysitting

Duetofailuretorespondtoconservativetherapy,shewassentfor

radiologicalevaluation.

Further exploration of this topic requires a review of the anatomy of the spine and of a differential diagnosis of low back pain

SpineAnatomy

http://www.columbiaspine.org

http://www.fla-ortho.com

http://www.sofamordanek.com

CERVICAL

THORACIC

LUMBAR

Transverse process

Spinous process

Vertebral body

Intervertebral disc

Pedicle

DifferentialDiagnosisLowBackPain

MECHANICAL Degenerativediskdisease,compressionfracture,musculoskeletal

sprainorstrain

NEUROGENIC Diskherniation,sciatica,spinalstenosis,infection,malignancy,

connectivetissuedisorder(ie.ankylosing

spondylitis)

Others: VISCEROGENIC

UTI,pyelonephritis,retroperitonealtumororbleed VASCULAR

Abdominalaorticaneurysm PSYCHOGENIC

With this differential in mind for patient BG, further imaging revealed infection of the spine.

IntroducingPottDisease Knownbymanynames:spinaltuberculosis,tuberculous

spondylitis,PottdiseaseorPottsdisease

Firstdescribedin1782byPercivalPott,aBritish orthopedicsurgeon.

DifferentialdiagnosisofPottdisease Pyogenicorfungalosteomyelitis Eosinophilicgranuloma Multiplemyeloma Multiplecompressionfractures Note:BrucellosisofthespineandPottdiseaseareradiologically

indistinct.

OurPatient:Imaging

Ms.BGsdiagnosiswasmadebasedonherimaging

Imaging

Plainfilmofthespinedemonstratedcompression

fractureL12withanteriorkyphosis

MRIspinerevealed

T12 L3vertebralosteomyelitis

L12compressionfractureswithforwardangulation

Cauda

equina

impingement

Leftpsoas

abscess

OurPatient:Radiograph

PACS, BIDMC

Lateral radiograph

Anterior collapse of L1,L2 vertebrae with loss of diskspace. (*).

Central lucencies

within the L1vertebrae (*).

OurPatient:CTTorso

PACS, BIDMC

Noncontrast

axial CT

Large left psoas

abscess with hypoattenuated

core region.

OurPatient:MRI

Spine

PACS, BIDMC

Sagittal

T2W

Destruction of L1-L2 disk space and collapse of adjacent vertebral bodies (*) with retropulsion

into the spinal canal(*). In image, edema in T12 to L3 vertebral bodies (*), suggestive of spinal osteomyelitis.

1 2

OurPatient:ClinicalOutcome

Diagnosis:Pott

diseasewasdiagnosedbasedon Radiologic

findings1)psoas

abscess2)continuousanteriorvertebralbodydestruction3)cordcompression

Emigrationfromanareawithendemictuberculosis Indolentnatureofsymptoms

Treatment: Patientwasplacedonbedrestandfittedforathoracolumbosacral

orthosis

(TLSO)

Underwentdebridement

andspinalstabilization Mycobacteriumtuberculosiswasisolatedfromsurgicalspecimensand

sputum

PlacedonalongcourseofRifampin,Isoniazid,Pyrazinamide,&Ethambutol

Pott

Disease:Epidemiology Pott

diseaseisuncommonintheUnitedStates

U.S.versusKenya(homelandofcasepatient)4/100,000/yr:384/100,000/yr

Spinaltuberculosislooselyreportedas100200casesyearly

Skeletaltuberculosis Accountsfor10%ofallcasesofextrapulmonary

TB

Targetsthehips,knees,spine Spinaltuberculosisismostcommon,accountsfor50%allskeletalTBcases

Clinicalpresentationvariesbygeographiclocation HighTBprevalence

Pott

diseaseiscommonlyseeninchildren Targetsthoracicvertebrae

UnitedStates Seeninimmigrantsfromendemiccountries,immunocompromised,

men>women Targetslumbarvertebrae

Pott

Disease:Pathophysiology Tuberculosisinfiltratesthespinevia

Hematogenous

spreadthroughthedensevasculatureofcancellous

boneoftheanteriorvertebralbodies

Lymphaticspreadfromparaaorticlymphnodespossiblebutrare

Upto75%ofinfectedindividualsdevelopasofttissue infection Commonlyoccursinthepsoas

muscle coldabscess Knownascoldabscessbecauseformsslowlyanddoesnotnormally

presentwith

heat,inflammationorpain

Paraspinal

fistulawhichmayformacommunicationwiththechest

wallorpelvicfloor

Leftuntreated,degenerationandinflammationofthe vertebraecauses Herniation

intothecordspace cordcompressionandcauda equina Kyphosis gibbous(severekyphosis) Paraplegia

Pott

Disease:Complications

Pappou et al.- http://ovidsp.tx.ovid.com.ezp- prod1.hul.harvard.edu/spb/ovidweb.cgi?WebLinkFrameset

Oguz et al.- http://www.springerlink.com.ezp- prod1.hul.harvard.edu/content/h482j21x5548q078/fulltext.pdf

Gibbous

Lateral radiographs and T2W MRI

Young male with gibbus

deformtity

(A) at thoracolumbar

junction seen on radiograph (B) and T2W MRI (C).

Cord Compression

Radiograph (1), sagittal

CT reconsturction

(2) and MRI (3) of a 70 year old man with Pott

disease.

Note continuous vertebral body destruction of thoracolumbar

spine, causing severe kyphosis.

Patient developed compression of the conus

medullaris, resulting in inability to ambulate.

2 3

1

Pott

Disease:Diagnosis PhysicalDiagnosis:

Usuallypresentswith4monthto3yearhistoryoflowbackpain

with

orwithoutassociatedneurologicaldeficits.

Signsofnearbycoldabscessorfistulamaybepresent

Only20%presentwithconcomitantTBlunginfection

RoutinelabtestsandtheMantoux

skintestareoflittlediagnosticaid

KEY POINT: Must maintain high clinical suspicion in order to make the diagnosis of tuberculous spondylitis in a timely fashion.

Pott

Disease:Pathology

Definitivediagnosis: Madeviasputumorbiopsyshowingacidfastbacilli

orpathognomonic

caseating

granulomas

intissuesample

http://library.med.utah.edu/WebPath

http://www.med.nus.edu.sg/path

Caseatinggranuloma

Acid fast bacilli

Pott

Disease:Imaging Menuoftests

Maystartwithplainfilm

tovisualizegrossdeformitiesi.e.kyphosis,fracture. CTisgoodforvisualizingdiscovertebrallesionsandparavertebral

abscess,

particularlyforabscesscalcification.

MRI

providesthebestvisualizationoftheextentofspinalcanalandsoft

tissueinvolvement.Allowsforearlydetection.

Examples of types of imaging modalities

>

Lateral Radiograph-

shows signs of early disk destruction (*)

> Coronal T2W MRI-

disk destruction and bone marrow edema (*)

> Transaxial

CT-

large left paravertebral

abscess (*)

RADIOGRAPH CT MRI Oguz et al.- http://www.springerlink.com.ezp- prod1.hul.harvard.edu/content/h482j21x5548q078/fulltext.pdf

Pott

Disease:

AdditionalImaging

Lesserusedimagingmodalities include:

Bonescintigraphy

Ultrasound

usefulinvisualizing

paraspinal

abscessesNigg et al.- http://www.springerlink.com.ezp- prod1.hul.harvard.edu/content/74l418224t055432/full text.pdf

46 year old male with spinal TB on bone scintigraphy

Increased radionuclide uptake in thoracic and lumbar spine (*) secondary to increased bony metabolism from infection.

Radiographs:GeneralFeatures FeaturesofPotts

onradiographinclude

Signsofinfectionwithlytic

lucencies

inanteriorportionofvertebrae

Diskspacenarrowing Erosionsoftheendplate Sclerosisresultingfromchronicinfection Compressionfracture Continuousvertebralbodycollapse Kyphosis;gibbous(severekyphosis)

Atypicalfeatures Softtissueswellingfromparaspinal

abscesses,+/

calcification

Involvementofonlyonevertebralbody Involvementofseveralvertebralbodieswithout

intervertebral

discitis

Bowingofribcagesecondarytocollapseofmultiplevertebralbodies Destructionoflateralorposterioraspectsofvertebralbodies

Radiographs:Erosions Lucentareainlateralaspectofadjacentvertebralbodies erosions(*) Lossofintervertebral

diskspace(*) Centrallucency

(*)withsurroundingsclerosissuggestingchronicinfection(*)

Pertuiset et al.- http://ovidsp.tx.ovid.com.ezp-prod1.hul.harvard.edu/spb/ovidweb.cgi?QS2

Radiographs:EndplateDestruction

Private Collection of Ferris Hall MD

Private Collection of Ferris Hall MD

Image 1Lateral radiograph of spinal TB in a 23 yo

man showing endplate erosion, loss of disk space(*), and anterior compression fracture of the lumbar spine.

Image 2Lateral radiograph of 56 yo

man with Pott

disease with additional features of sclerosis at vertebral endplates that have undergone severe compression and erosion(*).

2 1

Radiographs:Osteosclerosis

Private Collection of Ferris Hall MD

Private Collection of Ferris Hall MD

1 2

Image 1Frontal radiograph 45 yo

female. Note compression fracture with loss of intervertbral

disk space (*).

Image 2Lateral radiograph of 56 yo

male. Similarly, note compression fracture and secondary osteosclerosis

(*).

Radiographs: AtypicalFeatures

72 yo

M with

long history of longhistory of spinal TB.

Note collapse of multiple thoracic vertebrae (*) with resulting bowing in of ribs (*).

Paraspinal

abscess seen with circularcalcified mass (*).

Private Collection of Ferris Hall MD

Private Collection of Ferris Hall MD

72 yo

M with long history of longhistory of spinal TB.

Collapse of mulitplethoracic vertebrae (*)resulting in severekyphosis

(*).

CT:Features

FeaturesonCT

Softtissuefindings

AbscesswithcalcificationisdiagnosticofspinalTB;CTis

excellentmodalitytovisualizesofttissuecalcifications

Patternandseverityofbonydestruction

Patternofvertebralbodydestruction

framentary,osteolytic,

localizedandsclerotic,andsubperiosteal

Usedtoguideneedleinpercutaneous

needlebiopsyof

paraspinal

abscess

CT:Calcification

PACS, BIDMC

Noncontrast

axial CT

Large psoas

abscess (*) with central calcification (*); these features are highly diagnostic of spinal TB.

CT:BonyDestruction

Noncontrast

axial CT

Extensive vertebral body destruction causing bony fragments (*). Destruction of cancellous

bone indicated by hypoattenuation

of central vertebral body (*).

PACS, BIDMC

MRI:Features

HighlysensitiveandspecificforspinalTB Providesearlydetection Besttodistinguishexactextentofspinalcordandsoft

tissueinvolvement

Features Edemaofvertebraeanddiskspace Signsofspinalcompromisei.e.cordcompression Note:Poorlyvisualizescalcificationinabscesses

MRI:SpinalCordInvolvement

PACS, BIDMC

Sagittal

T2W (Images 1-3)and axial T1W (Image 4)

High intensity activity in T12 to L3 vertebrae indicative of infection (*) (*). Complete destruction of vertebral bodies with osseous retropulsion

into the spinal canal, causing cauda

equina

(*). On axial view, note destruction of vertebral body with loss of circular shape(*).

1 2 3

4

Pott

Disease:Treatment Variousimagingmodalitiesareusefulindeterminingextentofdisease. Treatmentoptionsthendependonthedegreeofspinaldestruction.

Mostpracticing

clinicianssimply

definePotts

as

EARLY

orLATE

disease.

GATA ClassificationOguz et al.- http://www.springerlink.com.ezp- prod1.hul.harvard.edu/content/h482j21x5548q078/fulltext.pdf

ConservativeTreatment

EarlyDisease:

Treatwithafourdrugregimenforsixtotwelvemonths

CommonantibioticsareRifampin,Isoniazid, Pyrazinamide,Ethambutol

Mostindividualsexperiencefullresolutionofsymptoms withappropriateantituberculosistreatment

SurgicalInterventions LateDisease:

Looselydefinedbyneurologicdeficits,spinalkyphosis

>40%,orfailure

ofmedicaltherapy Surgicaldebridement,abscessdrainage,and/orvertebralfusionin

additiontoantibiotics

PACS, BIDMC

Ms. BG post surgery

Young man with gibbous deformity (*) status post instrumentation surgery.Note stabilization of spine and resolution of gibbous (*).

Lateral radiograph

Our index patient, Ms. BG after spinal debridement and vertebral fusion.

Oguz et al.- http://www.springerlink.com.ezp- prod1.hul.harvard.edu/content/h482j21x5548q078/fulltext.pdf

Summary Imagingmodalities

areplainfilm,CTandMRI;MRIisgoldstandardfor

imagingspinalTB.

SpinaltuberculosisisnotcommoninU.S.,thereforemustmaintainhigh

clinicalsuspicionsoasnottooverlookdiagnosis,especiallyamong

immigrantpopulations.

DiagnosisandtreatmentofspinalTBinendemicareasisdifficultgiven

resourcelimitations;relyonradiographsandclinicalsignstofacilitate

earlydiagnosis.

ConservativeversussurgicaltreatmentofPott

diseasedependson

degreeofspinaldestruction,

makingearlydiagnosisessentialfora

positiveoutcome.

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Acknowledgements

Manythankstothefollowingcontributorsfor theirmuchappreciatedassistance.

GillianLieberman,MD

FerrisHall,MD

Gul

Moonis,MD

AlexanderCarbo,MD

MariaLevantakis

MichaelLarson

P O T T S D I S E A S E: A Radiological Review of Tuberculous Spondylitis AgendaOur Patient: Initial PresentationSpine Anatomy Differential Diagnosis Low Back PainIntroducing Pott DiseaseOur Patient: ImagingOur Patient: Radiograph Our Patient: CT Torso Our Patient: MRI Spine Our Patient: Clinical OutcomePott Disease: EpidemiologyPott Disease: PathophysiologyPott Disease: ComplicationsPott Disease: DiagnosisPott Disease: PathologyPott Disease: ImagingPott Disease: Additional ImagingRadiographs: General FeaturesRadiographs: Erosions Radiographs: Endplate DestructionRadiographs: OsteosclerosisRadiographs: Atypical FeaturesCT: FeaturesCT: CalcificationCT: Bony DestructionMRI: FeaturesMRI: Spinal Cord InvolvementPott Disease: TreatmentConservative TreatmentSurgical InterventionsSummaryReferencesAcknowledgements