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Pathology of Infections!
! Infectious!diseases,!agents,!diagnosis! Bacterial!infections:!bacteremia!vs!septicemia! ! !gm(=)!vs!gm(+)! Case!1:!gm(+)!bact!infection! ! !folliculitis,!furuncle,!carbuncle,!cellulitis,!impetigo! !! C"perfringens ,!Schistosoma! Case!2:!N!meningitides:!gm(=)!bact! ! !meningitis,!Meningococcemia,!Waterhouse!Friderichsen!syn! Case!3:!N!gonorrhea! ! !systemic!spread,!newborn—conjunctivitis! Case!4:!Salmonella!typhi! ! !Enteric/!Typhoid!fever! Case!5:!gm(=)!septicemia!"!septic!shock! Staphylococci!infections:!infla!lesions,!toxin=mediated! Streptococci!infections! Bronchopneumonia!aka!Lobular!pneu! Case!6:!gm(+)!Streptococcus!pneu!aka!Pneumococcal!pneu!aka!Lobar!pneu! ! !stages:!congestion,!red/!gray!hepatisation,!resolution! Fungal!pneu:!Pneumocystis!jiroveci/canarii! Case!7:!Rheumatic!Fever!from!Strep! ! !cross=reacting!Abs! Case!8:!Post=Strep!Glomerulonephritis! ! !immune=complex=mediated! Case!9:!Diptheria— Corynebacterium"diphtheria! Case!10:!Pseudo=membranous!colitis— Clostridium"difficile! Viral!infections:!Cytomegalovirus,!Herpes!zoster,!Rabies,!Coxsackie!A!&!B! Case!11:!Rickettsial!infections! ! !epidemic!typhus:! R"prowazeki! ! !Rocky!Mountain!Spotted!Fever:! R"rickettsia! ! !Q!fever:! Coxiella"burnetti! Fungal!infections:!Candidosis!(Moniliasis),!Crytococcus!(Torulosis),!Aspergillus,!Mucormycosis! Case!12:!Tuberculosis! ! !tubercle:!epitheliod!cells,!caseous!necrosis! !! 1 °!lesion/!complex,!Miliary!TB,!2°!TB! Infections!of!the!Immuno#compromised!! ! !Histoplasmosis! ! !Cat!Scratch!d! ! !Leprosy!(Hansen’s!d):!tuberculoid!vs!lepromatous! ! !Actinomycosis! ! ! !!
Importance!of!infectious!diseases!
! bact :"polymorphonuclear"leukocytes" (PMNs),"exudate! ! virus :"macs,"lymphocytes! ! fungus: "mixed"PMN"+"lymphocytes"+" macs"+"giant"cells!
Barriers0to0bacterial0invasion0 Settings0for0infection Skin=keratin!layer! Injury!insect!bites! IgA!in!mucosa,!mucus!in!gut,!lungs! IgA!deficiency! Ciliary!mvmt!in!bronchial!passages! Smoking,!cyctic!fibrosis! Normal!commensals! Antibiotic!therapy!
=through!pulmonary!veins!"!L=sided!heart!(mitral,!aortic!valve)!endocarditis! =distant!abscess:!brain,!kidney,!spleen,!brain! !
=major!problem!in!spite!of!improved!living!conditions,!vaccinations,!antibiotics! =more!that!10!million!deaths!/yr!in!developing!countries! ! =new!&!fatal!infections!are!still!being!recognized===ex:!SARS,!corona!virus!! ! Special!features!of! infectious!agents !! ! =caused!by!organisms—etiology!is!identifiable! ! =potentially!curable! ! =communicability:!potential!for!outbreaks!of!epidemics! ! =preventable! ! Infective!agents! ! =wide!range:!prions,!viruses,!bact,!fungi,!helminthes! ! =constant!battle!b/t!agents!&!host!defenses!"!outcomes!could!be!variable! !!!!!!
Infection!vs.!disease! ! =some!organisms!enter!the!body!but!get!cleared!=!not!an!infection! ! =others!enter,!multiply,!but!do!NOT!cause!tissue!damage!=! infection ,!but!there!is!no!disease! ! = infectivity :!ability!of!the!organism!to!produce!infection! ! = infectious"disease :!multiplication!&!tissue!damage! ! = pathogenicity :!ability!of!organism!to!multiply/!cause!tissue!damage! !!!!!!!!!!!!!!!! Steps!in!the!diagnosis!of!infectious!disease! ! =clinical!features:!hx,!physical!examination! ! =knowledge!of!epidemiology:!common!infections!in!the!geographic!area! ! =isolate!the!organism:!pus,!bl,!tissue,!fluids! ! =Ab!response:!demonstrate!rising!titers! ! =biopsy:!type!of!tissue!response,!demonstrate!organism!by!special!stains,!immunological!! !!! !!techniques,!PCR! ! =therapeutic!response!(ex:!malaria,!TB)! ! Body!response!to!infection!differs!depending!on!the!organism! ! = local: !infl!at!the!site!of!infection! ! = systemic !response!to!infection! !! !mediated!through!cytokines! !! !fever,!headache,!leukocytosis! !! !$!metabolic!rate! !! !memory!cells! ! =multiple!abscesses! ! =lymphatics:!lymphadenitis!(local!&!distant)! ! =venous!(regional!veins,!thoracic!duct)!"!reach!the!vena!cava!&!R!heart!"!right=sided!valve!(tri,!! ! !!!!pul)!=!endocarditis! ! =reach!the!lung!through!pulmonary!a!&!produce!lung!abscess! ! ! !
Case!1:!Gm!(+)!Bacterial!Infection! =50!yo!male!felt!itching!&!pain!in!forearm;!reddish!patch!on!skin!there.!It!was!swollen!&!painful.!! =a!day!later,!it!turned!yellowish!&!soft;!it!started!leaking!pus!the!next!day! =lesions!showed!plenty!of!gm(+)!bact,!necrosis,!PMNs!&!hyperemia!(acute!infl)! =how!did!bact!reach!this!site:! ! =what!are!other!routes!of!entry!for!microbes!into!the!body:! ! =sequence!of!events!once!bact!entered!skin:! ! =surrounding!skin!started!becoming!tender,!hard,!reddish.!!axillary!region!became!painful.!A!hard!nodule!could!be! palpated!there.!He!developed!fever.! =what!do!these!features!indicate:!! ! =what!is!the!cause!of!fever:! ! =He!developed!palpitations.!The!spleen!&!liver!became!enlarged.!Small!spots!of!hemorrhage!appeared!on!his!skin!&! mucous!mem!(petechiae).!He!lapsed!into!a!coma!&!died! ! =how!can!we!explain!these!features:! ! Inflammatory!lesions!of!bacteria:!skin!infections! 1.!folliculitis :!infla!/!infection!of!1+!hair!follicle! ! 2.!furuncle !(boil):!deep!folliculitis!creating!an!abscess;! S"aureus! =painful!swollen!area!on!skin! !=caused!by!accumulation!of!pus/dead!tissue! ! !! !!!!!!!!!
4.!impetigo :!bacterial!skin!infection;! Staph."aureus,""Strept."pyogenes! = honeyJcolored !scabs!formed!from!dried!serum!on!a!! !!!erythematous!base! =begins!as!a!small!pustule!that!ruptures!&!leaves!an!erosion!! =etiology:!poor!hygiene;!ex:!kids!rubbing!their!face!w/!dirty!hands! =resolves;!no!scar!b/c!only!affects!epidermis!
3.!carbuncle :!collection!of!several!furuncles! =numerous!pus!filled!w/!PMNs,!macs,!&!necrotic!cells! =spread!of!infection:!skin!"!abscesses!"!! lymphatics!"!venous!&!other!organs! !
%CSF=pyogenic!meningitis! =turbid!(cloudiness)! =high!in!proteins! =lots!of!PMNs! =&!in!glucose!
Clostridium0perfringens =gm(+)!bacilli,!anaerobic,!produce!spores;!found!in!soil! =invade!traumatic!&!surgical!wounds! = myonecrosis"aka"gas"gangrene! ! =gas=forming!organisms:!degradative!enzymes!produce!gas!in!tissues! ! =deadly!form!of!gangrene!"!medical!emergency! =secrete!12! exotoxins"="necrosis ;!most!important:! *alpha"toxin"(Lecithinase)" ! !degrades!lecithin—a!major!component!of!cell!mem! ! !destroys!RBCs,!platelets!&!muscle!fibers!(myonecrosis)! ! !enzymes!released!from!necrotic!tissue! !!!!!!!!!!!!!!!! Parasites:! Schistosoma! =trematode!group!of!parasites! =blood!flukes;!reside!in!veins,!mesenteric,!urinary!bladder! =GIT:!Schistoma!mansoni/!japonicum! =bladder:!S!hematobium—bladder!carcinoma! =liver:!hepatomegaly,!fibrosis,!portal!HTN! =most!changes!due!to!rxn!to!eggs!in!the!liver,!spleen,!or!wall!of!gut,!bladder! = eggs"induce"granulomas"! "fibrosis! ! !!!!!!!!!!!!!!!! Case!2:! Neisseria0meningitides >>!Gm(>)!Bacteria! =10!yo!student!developed!fever,!headache!&!neck!stiffness! =He!rapidly!became!drowsy!&!went!into!a!coma;!death!occurred!w/in!48!hrs! =CSF!showed! Neisseria"meningitides !:!gm(=)!diplococci! ! what!term!would!you!used!to!indicate!infection!of!the!meninges:!! ! how!did!the!organisms!reach!the!meninges:!! ! what!type!of!tissue!response!would!you!see!in!the!meninges:!! ! what!changes!would!you!expect!in!the!CSF:!! ! Neisseria0meningitides =gm(=)!diplococcic! =transmitted!by!respiratory!droplets!(nasopharynx)! =most!pts!develop!no!sym!except! mild"‘flu’Jlike"symptoms"="carrier! =less!commonly!invade!bl!"!septicemia:!meningococcemia! =in!some!pts,!localize!in!the!meninges!"!meningitis! ! Bacterial!Meningitis! = pyogenic"infla"of"meninges"&"subarachnoid"space! =bacteria!colonize!in!nasopharynx!"!drain!into!thoracic!duct!into!lymphatics! !"!enter!bloodstream!"!enter!CSF! *infla!does!NOT!extend!into!the!brain!parenchyma!b/c!of!BBB! =clinical:! triad =!1.!Headache!2.!Nuchal!rigidity!(neck!stiffness)!3.!photophobia! ! also:!fever,!cloudy!consciousness! =diag:!spinal!tap!(CSF)—PMN,!$!protein,!&!glucose,!! !!!demonstrate!organisms!(smear)!=!gm(=)!diplo! normal!
cloudy!
Organisms!in!meningitis 0 0>!2!mo! Streptococcus"agalactiae,"E"coli,"&"Listeria"monocytogenes" note:"S."aga."passed"in"birth"canal"from"mom’s"vagina" Infants!&!children! Strep"pneumoniae,"Neisseria"meningitidis,"H"influenza"
Adolescents! N"meningitides"
20>60!yrs! Streptococcus"pneumoniae,"Neisseria"meningidis,"Listeria" moncytogenes,"gm(J)"bact"
*! Hemophilus"influenza !used!to!be!a!common!cause!of!meningitis!(children!&!young!adults)!"! rare!now!due!to!vaccinations!
Case!3! =18yo!sexually!active!female!developed!dysuria!(painful!urination)!&!vaginal!discharge! =the!discharge!revealed! Neisseria"gonorrhea —gm(=)!diplococcic! ! what!would!be!the!tissue!response! ! how!does!the!infection!spread;!what!are!the!features!of!systemic!spread! ! what!are!the!complications!related!to!spread!to!the!fallopian!tubes! ! if!this!person!had!the!infection!at!the!time!of!delivering!a!baby,!what!lesions!can!you!expect!the!baby!to!develop:! ! Neisseria0gonorrhoeae = gm"(J)"diplococci"" STI! =males! ! !urethritis,!epididymitis;!urethral!discharge!&!dysuria!(painful!urination)! ! !oropharyngitis!&!proctitis!(infla!of!the!rectum)!in!homosexual!males! =females! ! !cervicitis,!salpingitis!(infection/infla!of!fallopian!tubes)! ! !peritonitis!(infla!of!peritoneum)! ! !vaginal!discharge,!inter=menstrual!bleeding;!!pelvic!inflammatory!d!(PID)! ! !!!!if!chr:!scarring!of!the!fallopian!tubes!"!infertility!! ! Gonrrhea!dissemination! ! =rare!(0.5=4%!cases)!hematogenous!(carried!in!blood)! ! =tenosynovitis!(infla!of!the!lining!of!sheath!that!surrounds!tendon),!arthritis! ! =hemorrhagic!skin!lesions! ! =endocarditis! ! =rarely!meningitis! ! Gonorrhea!in!a!newborn! ! =infection!acquired!during!passage!of!the!fetus!through!cervix!during!labor! ! = purulent"conjunctivitis !(opthalmia!neonatorum)! ! =use!of!erythromycin/!silver!nitrate!eye!drops!after!birth!can!prevent!it! ! Gonorrhea!diag! ! =males:!microscopy!of!exudate—PMN!&!gm(=)!dipl! ! =females:!culture!of!exudate—essential!b/c!gm(=)!dipl!are!a!normal!part!of!vaginal!flora! ! =could!yield!false!neg!result!if!there!are!fewer!organisms! ! =*Chlamydial!infection!can!also!produce!similar!sym!&!is!more!common!
S.ALE!
S.PNH!
!!!!!!N!
S.PNL=!
Eat!bact"cross!ileal!wall! into!bl"liver!&!spleen!=! enlarged!"!macs!phago! bact!=!typhoid!nodules"! macs!w/!ingested!bact! end!up!in!gall!bladder! "bile"back!to!the! gut"re=enter!ileal! wall"recognized!=!T&B! action!+!necrosis!
Case!4:! gm(>)!Salmonella!typhi—Enteric/typhoid!fever! =20!yo!female!developed!high!fever!&!weakness! =liver!&!spleen!were!enlarged!&!soft! =1!wk!later,!she!developed!diarrhea!&!blood!in!the!stools! =abdomen!was!tender;!evidence!of!leukopenia!(&!in!#!of!WBCs!in!blood)! =blood!sample!was!drawn!on!the!4th!day!of!the!illness!"!showed!growth!of! Salmonella"typhi! =in!the!3rd!wk,!she!developed!severe!anemia!&!heart!failure! ! how!do!these!organisms!enter!the!body:! ! what!is!the!route!of!spread!in!the!body:! ! what!are!the!tissue!responses!over!the!course!of!the!illness:! ! how!do!you!explain!anemia!&!leukopenia:! ! why!did!she!develop!heart!failure!later!in!the!course!of!illness:! ! can!she!become!a!carrier!of!the!infection:! ! how!do!you!treat!this!situation:! ! Typhoid!fever!=!Enteric!fever! ! = Salmonella"typhi :!gm(=)!bacilli! ! =acquired!through!ingestion:!contaminated!food,!water!(transferred!in!feces)! wk !1! ! =enter!ileal!wall!(no!lesions!at!this!time)!"!enter!bl!stream!"! bacteremia"! wk! 2! ! > liver!enlarged!=!typhoid!nodules:!composed!of!Kupffer!cell!hyperplasia! ! =minute!foci!of!hemorrhagic!necrosis,!collections!of!macs!! !! " typhoid"nodules :!macs!that!contain!bact,!RBCs,!degenerated!lymphocytes! ! =spleen:!enlarged!soft!spleen!w/!splenitis,!typhoid!nodules! wk! 3! ! > bact!excreted!through!gall!bladder!in!bile!"!lumen!of!gut!"!re!enter!gut!wall!through!ileum! ! Jsensitization !has!occurred!during!this!period!"!contact!w/!organisms!produces!lymphoid!! ! !!!!hypertrophy!($!lymph!tissue)!&!necrosis!in!the!mucosa!! !!!!!!!!!!!!!!
Staphylococci!infections! ! =gm(+)!cocci;!normally!colonize!in!human!skin;!entero=,!exo=,!exfoliative=TOXINS! ! =common!species:! S"aureus,"S"epidermidis,"S"saprophyticus! !! most!infections!caused!by! S"aureus" " 2"types"of"lesions:" 1.!inflammatory!lesions!of!Staphylococci! =skin:!folliculitis,!furuncle,!carbuncle,!cellulitis,!impetigo,!paronychia!(infection!in!bed!of!fingernail),!!!!! !!!surgical!wound!infection! =postpardum!mastitis:!infla!of!breast!due!to!breast=feeding! =bacteremia! =endocarditis:!tricuspid!valves!(RIGHT!heart)—common!in!IV!drug!addicts! =osteomyelitis:!organisms!reach!bone!hematogenously!(through!blood)!or!directly!from!adjacent!abscess!! !!!!or!through!traumatic!implantation! =pneumonia:!bronchopneumonia,!abscess!w/!watery!pus,!empyema!(pus!in!pleural!space)! =bacteremic!abscesses:!lung,!kidney,!brain! =80%!PCN!resistant!(MRSA)! ! ! 2.!toxin!mediated!lesions!of! Staphylococci!!* = enterot oxin:" food!poisoning! !!![do!NOT!confuse!w/! endo toxin!]! = exo toxin :!!TSS!(Toxic!Shock!Syndrome):!tampon"!leads!to!! !!!growth!of!Staph!"!release!of! exo toxin !into!circulation!"!! !!!rash,!conjunctivitis,!vomiting,!diarrhea;!superantigens! = exofoliatin toxin: Scalded!Skin!Syndrome ! !!!!!!!!!!!!!!!! Streptococci!Infections! ! =gm(+)!cocci=diplo!or!strepto=! ! =produce!hemolysis:!classified!in!to!α,!β.!.!.! !! !further!classified!(Lancefield!grouping):!group!A!beta!hemolytic!Strep,!group!B…! ! Streptococcus0pyogenes " =Group!A!beta!hemolytic;!most!important!human!pathogen!! ! =direct!damage:!suppurative,!cellulitis,!abscess,!pneumonia! ! = exo toxin! ! =indirect!damage!by!immune!responses! ! =ex:!Post=Strep!Glomerulonephritis,!Rheumatic!Heart!d,!Scarlet!Fever! ! ! ! !! !!!!!!
Scarlet!Fever!strawberry! tongue!
3!kinds!of!pneumonia:! 1.!Bronchopneumonia/!! 2.!Streptococcal!pne/!! 3.!Atypical— Pneumocystis!jiroveci!
Bronchopneumonia!aka!Lobular!pneu! ! =etiology:! many!different!agents ;!* Klebsiella,"E"coli,"Psuedomonas,"Staph"(aureus)! " " =occurs!in!pts!w/!weaker!immunity:!children,!elderly,!bed=ridden!! ! = destruction!of!bronchioles,!alveoli! ! =can!coalesece!to!involve!the!entire!lobe!mimicking!lobar!pneumonia! ! pathogenesis! ! =hx!of!upper!respiratory!infection:!begins!as!an!acute!bronchitis!! ! !!!w/!spread!of!infla!exudate!into!adjacent!alveoli! ! =no!macs!in!bronchioles!to!clean!up!debris!=>! scarring" ! complications! ! =abscesses!&!empyema! ! gross = patchy !involvement!of!the!lung;!yellow,!pale!areas!around!bronchioles! !!!!!!!!!!
Case!6:!gm(+)!Streptococcus!pneumoniae!aka!Pneumococcal!pneumonia!aka!Lobar! =20!yo!healthy!man!got!drenched!in!rain!in!cold!weather.!He!felt!weak!&!exhausted.!The!next!day!he!developed! fever,!chest!pain,!cough!&!blood=tinged!sputum! = Streptococcus"pneumoniae =gm(+)!was!demonstrated!in!PMNs!in!the!sputum!&!by!blood!culture! =Chest!xray!showed!uniform!consolidation!of!the!right!lower!lobe! =He!recovered!completely!in!10!days!&!the!chest!xray!had!returned!to!normal! ! what!was!the!tissue!response!in!alveoli! ! how!does!the!infection!spread!in!the!lungs! ! why!was!complete!recovery!possible! ! what!complications!can!arise!in!pneumonia! ! Pneumococcal!pneumonia.!aka!Lobar!pn.! ! =etiology:! Streptococcus0pneumonia !(90%)! ! =healthy!young!adults:!exposed!to!cold,!strain,!exhaustion! ! pathogenesis! ! =acute!infection!due!to!bact;!no!preceding!respiratory!infection! ! =begins!in!alveoli!"!spreads!via! pores!of!Kohn !to!involve! entire"lobe !*prefers!lower!lobes! ! =passes!through!different!stages!
micro =destruction!of!bronchioles!&!alveoli!by!PMNs! =infla!exudate!inside!alveoli!"!congestion,!distended!alveoli! =WBC!infiltration! !
Fungal!pneumonia! ! >Pneumocystis!jiroveci! ! =disease!of!immunocompromissed!pts—HIV!(defining!criteria!"!AIDS)! ! =atypical!pneumonia:!latent!infection!(90%!of!pop!is!infected)! ! =sym: !low !grade!fever,!dyspnea,! NONJproductive"cough! ! micro = Acellular0exudate !(there!are!no!cells!IN!the!exudate)! !!!!mostly!contains!proteins!=!‘ cotton"candy"exudate’ !! =mixed!tissue!response:!PMNs,!lymphocytes,!monocytes!&!giant!cells! =infla!cells!in!the! interstitium !(not!inside!alveoli)! =thickened!alveoli!septae!&!minimal!mononuclear!infiltrate! !!!!!!!!!!!
Case!7:! Rheumatic!fever!caused!by! Streptococci! =12!yo!girl!developed!pharyngitis;!Throat!swab!revealed!pathogenic!Streptococci! =2!weeks!later!she!developed!fever,!arthritis,!skin!nodules,!&!carditis! =ASO!titers!were!elevated! ! why!did!the!heart!&!other!CT!get!damaged! ! why!was!there!a!gap!of!2!wks! ! what!chronic!sequel!can!you!expect!in!the!heart! ! Rheumatic!fever! ! =infla!disease!that!occurs!following!a!Strep!pyogenes!infection! ! pathogenesis!! =initial!Streptococcal!sore!throat,!skin!infection![specific!strains]! = cross>reacting!antibodies:! Abs!generated!to!M!protein!(surface!antigen)! !!!!of!the!bact!cross!react!w/!tissue!glycoproteins!in!joints,!heart,!skin,!etc! "! !!!! get!deposited!in!tissues!&!elicit!infla!rxn!at!site!of!deposition! =lag!period!2=3!wks!after!the!initial!infection! =then!develop!symptoms:!fever,!polyarthritis,!carditis,!chorea,!skin!nodules,!erythema!! ! ACCNE:!arthritis,!chorea,!carditis,!nodules,!erythema!marginatum! =sym!NOT!a!result!of!bacteremia!or!direct!damage!by!the!bact! !! !
silver0stain =organisms!are!in!cyst=like!structures;!have!a! ‘cup=like’!shape! =occur!singly!or!in!aggregates!
Aschoff! !body!
Anitschkow! cell!
Macallum’s!! Patch!
fish!mouth! mitral!stenosis! pericarditis!
Rheumatic!Heart!disease! ! =carditis:!Aschoff!bodies!in!the!heart! ! = Rheumatic"carditis !can!become!chronic!"!mitral!stenosis! !!!!!!
Case!8:!Post>Streptococcal!Glomerulonephritis!=!immune>complex!mediated! =17!yo!male!developed!pustules!on!the!skin!due!to!streptococcal!infection! =3!wks!later,!he!developed!acute!onset!fever,!weakness,!oliguria,!hematuria,!&!HTN! =glomeruli!were!acutely!inflamed!although!the!organisms!could!not!be!demonstrated!there! ! what!was!the!mechanism!of!glomerulonephritis! ! what!is!the!usual!outcome! ! Post>Streptococcal!Glomerulonephritis!=!immune>complex!mediated! ! =initial!Streptococcal!sore!throat,!skin!infection!(specific!strains)! ! =lag!period!of!1=4!wks!after!the!initial!infection! ! =then!develop!acute!malaise,!fever,!oliguria!(low!output!of!urine),!hematuria!(blood!in!urine),!! ! !!!azotemia!($BUN,!creatinine!&!&GFR),!HTN! ! pathogenesis! ! =Ab!to!Strep!is!produced!&!circulates!in!blood! ! =Strep!Ags!&!the!Ab!to!it!combine!=!form!immune!complexes!that!circulate!in!blood! ! = immune"complexes"get"deposited"in"the"BM"of"the"glomeruli! ! =activate!complement!&!induce!acute!infla!"!glomerulonephritis! ! =resolves!spontaneously!in!most!pts!as!the!immune!complexes!are!cleared!up! !!!!!!!!!!!!!!!!!!
=kids!after!pharyngeal!or!skin!infection! (mosque!bite)! =type!3!hypersensitivity!rxn! =reddish=brown!urine!w/!proteins! =complement=mediated!destruction!of!BM! =immune!complex!deposition!in! glomerulus!
Pseudo>membranous!colitis! ! = Clostridium"difficile =!gm(+)!bacillus! ! =antibiotic=associated!colitis!!(after!antibiotics!are!administered!for!some!other!illness)! ! = broad"spectrum"antibiotics !eliminate!normal!flora!of!gut!that!normally!afford!protection! !! clinical! ! =severe!mucosal!suppurative!infla!=!multiple!ulcers! ! =small!vascular!thrombosis!! ! =necrotic!mucosa!forms!a!pseudomem!that!can!be!seen!on!colonoscopy! ! ! !!!!!!!!!!!!!!!! Viral!infections! Effects!on!cells! =cytopathic:!damage!to!infected!cells! ! !Hep!B! =perinuclear!vacuolation!! ! !HPV=cervix! =nuclear!&!cytomplasmic!inclusions:! ! !!CMV,!herpes!simplex,!varicella!zoster,!rabies! =multinucleate!giant!cells! ! !herpes,!measles,!HIV! =cell!proliferation! ! !wart,!neoplasm! ! inflammatory!response!to!viruses! ! = no"PMN! ! =predominantly!lymphomononuclear!cells! !! * lymphocytes ,!monocytes,!plasma!cells! ! =Ab!response!may!be!protective!(used!for!diagnosis)! !!!!!!!!!!!!!!!! Cytomegalovirus!aka!HHV5! ! =immunocompromised;!vertical!transmission!also!possible! ! =causes!Mononucleosis!(monocytes)!aka!kissing!disease! !! !note:!Infectious!Mononucleosis!caused!by!EBV!! ! >CMV!pneumonia! ! =affects!other!parts!of!body! ! =diagnosis:!Ab!titers,!urine!sample! ! = cytopathic!effect!of!the!virus :!cells!combine!&!become!enlarged! !! !Herpes!virus!has!a!tendency!to!fuse!cells!together!! ! =rxn!mainly!by! lymphocytes! (b/c!viral)! ! ! %alveolar!cells!infected!w/!Cytomegalovirus! =enlargement!of!cell;!multinucleate!giant!cell! =Owl’s!eye!! !!!!1.! intranuclear"inclusions !(large!&!surrounded!by!halo)! ! =amphophilic!or!basophilic!! !!!!2.! cytoplasmic"inclusions :!aggregates!of!protein!coat/!viral!envelope! !
clinical0photo =Shingles:!painful!rash!along!distribution!of!a!dermatome! =viral!prodrome!=!fever,!malaise! =lesions!occur!in!different!stages:!papule"!vesicle"!! !!pustule"!scab! !
micro = Negri"body :!intracytoplasmic! eosinophilic!inclusion!in!neurons! !
micro = patchy "necrosis"of"cardiac"myocytes !! **lymphyocytic!infiltration:!damage!is! caused!by!infla;!2°!condition! =distinguish!histo!from!MI:! !!!!MI!=!PMNs,!macs;!sheets!of!necrosis! !!!!myocarditis!=!lymphocytes,!patchy!! !
Herpes!zoster!aka!Varicella!Zoster!virus! ! =etiology:!inhalation!of!contaminated!water!droplets! ! =virus!remains!dormant!in!DRG!"!latent!infection! ! =Tzanck!smear:!scraping!of!the!lesion!stained!w/!Wright’s!or!Giemsa!to!visualize!Tzanck!cells!! ! micro = acidophilic"intranuclear"inclusions !(Cowdry!A)!! =multinucleated!giant!cells:!cells!fuse!together! =[arrow]!nuclear!molding!! =[arrowhead]:!eosinophilic!haloed!nuclear!inclusions! !!!!!!!
Rabies!virus! ! =etiology:!rapid!dogs,!bats! !! !bite"virus!travels!to!peripheral!nerves!"!ascend!spinal!cord!to!brain!! ! =long!incubation!period;!depends!how!far!the!bite!is!from!CNS! ! clinical! !! =hydrophobia==just!looking!at!water!b/c!the!pt!is!having!! ! !!difficulty!swallowing!due!to:!laryngeal!spasms!! ! !!!(CNS!excitability!causes!muscles!to!contract)! ! =stupor! !!!!!!
Viral!Myocarditis! = Coxsackie"A"&" B0 virus !infection;!!~asymp! =myocarditis:!infection,!infla,!damage!to!♥! =immune!rxn—virus!has!regions!(epitope)!similar!to!myocytes!! !!!!!!!!!!
Rocky!Mountain!Spotted!fever:! Rickettsia0rickettsia****! ! =obligate!intracellular,!gm(=),!zoonotic!! ! =Oklahoma,!Tennessee,!Arkansas,!GA!( GOAT)! ! !!!!!(note:!eastern!states,!not!necessarily!mountainous)! ! =diagnosis:!immunofluorescence!on!skin!biopsy!! ! clinical! ! rash!starts!w/!palms!&!soles!! ! !!!!!!CARS:!conditions!w/!rash!on!palms/soles!! ! !!!!!pneumonic:!Cocsackie!A,!R!rickettsia,!Syphilis! ! =fever,!headache,!myalgia!(m!pain)! ! !!!!!"!then!skin!rash!(after!2=5!days)! ! =severe!=!CNS!&!lung!involvement! ! micro =vascular!necrosis,!hemorrhage,!vasculitis! =organisms!invade!endothelial!cells!of!sm!bl!vessels,!thrombosis! ! !!!!!!!!!!!!!!!! Fungal!infections! ! =tissue!infla! ! =mixture!of!acute!&!chr! ! =* PMN"+"lymphocytes"+"monocytes"+"giant"cells !=!gives!a!clue!to!look!for!fungi! ! =tendency!to!invade!bl!vessels!=!hemorrhage,!thrombosis,!infarction! ! =exception:!Crytococcus!"!sometimes!elicits!no!infla!response! ! !!!!!!!!!!!!!!!! Candidosis!(Moniliasis)!! ! =fungus:!Candida!albicans!! ! =Oral!Thrush,!vagina!muco!cutaneous! !! !~!superficial! !! !can!become!invasive!&!disseminated!in!immunecompromised!pts! !! !!!"!abscesses!in!kidney,!liver,!♥! ! =!AIDS!defining!criteria!! ! clinical0photo =Oral!Candidiasis! =coating!or!patches!of!white/yellow!slough!in!oral!cavity! !!!!!!!!!!
microD0PAS0stain =Candida!albicans! =pink,!slender!pseudo=hyphae!(yeast!form!):!budding!yeast!cells! ! !yeast!form!aka!pseudo!hyphae!indicates!pathologic!form! =infection!is!superficial!=!can!be!scraped!easily!for!sampling! ! !compare!w/!diphtheria!pseudomembrane,!which!must!be! ! !!!!excised!for!sample!!
Crytococcus—Torulosis! ! =fungus:! Crytococcus!neoformans !! ! =lungs!most!commonly!involved—inhaled!spores!from!bird!dropping!! ! =disseminates!in!immunocompromised!"!meningitis! ! ~granulomas!(immunocompetent)!w/!giant!cells!"!resolves! ! =sometimes!infla!rxn! absent !"!clue!to!search!for!Cryptococcus! ! =diag:!latex!agglutination!test!using!Abs:!most!specific! ! =PAS,!silver!stain,!mucicarmine!stain! !!!!!!!!!!!
Indian0Ink0stain0of0CSF =!virulence!factor!=! thick"capsule !"!need!to!do!negative!staining!b/c!! !!!stain!does!NOT!penetrate!spore! =organisms!appear!as! clear"halo;"negative"staining! =*polysaccharide!capsule! !!!!!!!!!
Aspergillosis! ! =fungus:!Aspergillus!!! ! =inhalation!of!fungal!spores!(yeast)!!!! !!! =demonstrate!by!PAS,!silver!stains! ! types! ! = opportunistic :!in!immune=suppressed,!leukemia! ! = Allergic!Aspergillosis! !! !asthma,!alveolitis,!allergic!bronchpulmonary!Aspergillosis!! !! !$IgE,!eosinophilia,!type1HS!allergic!rxn!to!fungi!in!the!bronchi! !! !can!lead!to!chr!obstructive!pulmonary!d!if!untreated! ! = Colonizing!Aspergillosis :! fungal"balls !in!lung!cavities;! seen"in"TB,"old"absecesses/"previous"" " " ""lung"disease" ! = invasive :!necrotizing!pneu,!vascular!invasion! ! = vascular!invasion !=!dissemination!to!heart,!brain,!kidney!
gross =fungus!affects!ONLY!the!grey! matter!in!the!brain! =cystic!lesion! !
Mucicarmine0stain =Crytococcus!neoformans!in!the! perivascular"space !of!the!brain! =fungi!multiply!&!extend!the! perivascular"space"&"subarachnoid" =survive!intracellularly!in!macs! =cystic!spaces!containing! ‘soap"bubble’Jlike"organisms! !
