Blood Vessels. Anacutenecrotizingvasculitisinvolvingcapillaries,smallarteries,andarteriolesmaybepresentinanytissue.Thearteritisleadstofibrinoidnecrosisofthevesselwalls.Inchronicstages,vesselsundergofibrousthickeningwithluminalnarrowing.
Kidney. Upto50%ofSLEpatientshaveclinicallysignificantrenalinvolvement,andthekidneyvirtuallyalwaysshowsevidenceofabnormalityifexaminedbyelectronmicroscopyandimmunofluorescence.Renalinvolvementtakesanumberofforms,all
Table 5.12 Clinical and Pathologic Manifestations of Systemic Lupus Erythematosus
Arthritis,arthralgia,ormyalgia80–90 *Percentagesareapproximateandmayvarywithage,ethnicity,andotherfactors.TablecompiledwiththeassistanceofDr.MeenakshiJolly,RushMedicalCenter,Chicago.
ofwhichareassociatedwiththedepositionofimmunecomplexeswithintheglomeruli.Accordingtothecurrentlyacceptedclassification,sixpatternsofglomerulardiseasearerecognized.Itshouldbenotedthatthereisoverlapwithintheseclassesandthatlesionsmayevolvefromoneclasstoanotherovertime.Thus,theexactpercentageofpatientswitheachofthesixclassesoflesionsisdifficulttodetermine.SufficeittosaythatclassIistheleastcommonandclassIVisthemostcommonpattern.
Minimal mesangial lupus nephritis (classI)isveryuncommon,andischaracterizedbyimmunecomplexdepositioninthemesangium,identifiedbyimmunofluorescenceandbyelectronmicroscopy,butwithoutstructuralchangesbylightmicroscopy.
Mesangial proliferative lupus nephritis (classII)ischaracterizedbymesangialcellproliferation,oftenaccompaniedbyaccumulationofmesangialmatrix,andgranularmesangialdepositsofimmunoglobulinandcomplementwithoutinvolvementofglomerularcapillaries.
Focal lupus nephritis (classIII)isdefinedbyinvolvementoffewerthan50%ofallglomeruli.Thelesionsmaybesegmental(affectingonlyaportionoftheglomerulus)orglobal(involvingtheentireglomerulus).Affectedglomerulimayexhibitswellingandproliferationofendothelialandmesangialcellsassociatedwithleukocyteaccumulation,capillarynecrosis,andhyalinethrombi.Often,therealsoisextracapillaryproliferationassociatedwithfocalnecrosisandcrescentformation(
Fig.5.24A ).Theclinicalpresentationrangesfrommildhematuriaandproteinuriatoacuterenalinsufficiency.Redbloodcellcastsintheurinearecommonwhenthediseaseisactive.Somepatientsprogresstodiffuseglomerulonephritis.Theactive(orproliferative)inflammatorylesionscanhealcompletelyorleadtochronicglobalorsegmentalglomerularscarring.
Diffuse lupus nephritis (classIV)isthemostcommonandsevereformoflupusnephritis.ThelesionsareidenticaltothoseinclassIII,butdifferinextent;indiffuselupus http://ebooksmedicine.net