Robbins pathology companion infectious disease Flashcards

Terms Definitions
Endotoxin causes septic shock by causing the realease of___
TNF, IL 1, IL 2
3 examples of Host response to infection causing the injuriuos effects.
HBV damaging liver cells, TB causes tissue damage when TB is attempted to be sequesterd, Post-strep glomerulonephirits from immune complex deposition
Measles aka
Rubeola
What class of virus is measles
RNA paramyxovirus
Extremem complications of measles?
Subacute slerosing panencephalitis, inclusion body encephalitis.
Oral lesions of measles called...
Koplik spots
Pathognomonic cells of measles?
Where do you find them?
Warthink-Finkeldey cells--Multinucleated giant cells with eosinophilic nuclear inclusion bodies.

In thelymphoid organs, lungs and sputum.
How does measles affect the lymphoid organs?
Follicular hyperlasia, large germinal centers, Warthin-Finkeldey cells
Mumps is a ___ virus.
Paramyxovirus RNA
Mumps most often causes enlarged ___
Parotid glands
Mumps can infect what organs?
Parotids, Testes, pancreas, CNS
Tissue infected with mumps microscopically would show _________
Intersititial edema, diffuse macrophages, lymphocytes and plasmam cell infiltrates.
Polio virus is in what family of viruses?
unencapsulated RNA enterovirus. Other enterods coxsackievirus, echovirus, hep A.
What part of nervous system can polio invade?
Motor neurons or brain stem (leads to bulbar poliomyelitis--->resp paralysis)
WNV is what class of virus?
Arbovirus (arthopod-borne) of the flavivirus (includes dengue and yellow fevers, eastern encephalitis).
Symptoms of WNV?
Acute falccid paralysis due to meningitis, encephalitis, meningoencephalitis). Indistinguishable fomr polio. Rarely hepatitis, myocarditis, pancreatitis.
Who's at greatest risk for WNV?
Elderly and immunosuppressed.
Viruses that cause Viral Hemorrhagic fever?
BAFF - Bunyaviruses, Areanaviruses, Filoviruses, flaviviruses
Most viral hemorrhagic fevers infect _________. What causes the hemorrhaging?
Endothelial cells. Bleeding causes by endothelial dysfunction, platelet dysfunction or thrombocytopenia.
Herpes viruses are what type?
DS DNA
HSV-1 leads to _________.
Cold sores, gingivostomatitis, corneal blindness
HSV-2 leads ______.
Genital warts
Leading causes of corneal blindness?
HSV-1 infections
Worst cases scenario in HSV infections
Disseminated viseral infections and encephalitis.
Life cycle of HSV?
Replicates in infected skin or membrane, resides latently in neurons, spreads from ganglia back to skin or MM.
Microscopic appearance of HSV infection?
Cowdry-type A inclusions--Virion inclusions cause chromatin to be compressed against nuclear membrane. Tzanck prep shows multinucleated syncytia.
In most cases, CMV is ______.
Asymptomatic nearly always except in neonatesa nd immunosuprressed.
Most common pathogen infected AIDS victims?
CMV - life threatening
Histologic appearance of CMV infection?
Cellular enlargement, purple intranuclear inclusions with clear halo, small basophilic cytoplasmic inclusions
Where does VZV lay dormant?
In sensory dorsal root ganglia.
Histologic appearance of VZV?
Vesicles contain epithelial cell intranuclear inclusions. Blisters appear identical to HSV (Intranuclear inclusions compressing chromatin against nuclear membrane).
Why is Hep B so hard to remove from the body?
High mutation due to it's DNA denome being transcribed by an RNA template (no proofreading)
How does Hep B damage liver cells?
HBV infects hepatocytes but the immune reponses causes the damgage.
What determines if a person is a Hep B carrier or not?
cytotoxic T cell response can clear it.
Hep B puts one at risk for _______
Hepatocellular carcinoma, cirrhosis and esp. chronic hepatitis.
3 viruses implicated in causing human cancer?
EBV, HPV, HTLV-1
EBV infection symptoms?
fever, sore throat, generalized lymphadenopathy, splenomegaly, very high WBC count.
Life cycle of HBV?
Infects nasopharyngeal or ooparyngeal epitheliaium, progressing to B cells--the reservior. T cells proliferate kill the infected B cells.
HBV infections demonstrate what special cells in lymph nodes?
Reed-Sternberg-like cells (large binucleate cells).
EBV + immunocompromised can lead to _______.
B-cell lymphoma.
EBV can lead to what 2 types of cancer?
B-cell lymphoma and Burkitt's lymphoma.
Mutation in EBV associated Burkitt's lymphoma?
8:14 translocation on the c-myc oncogene into the Ig heavy chain region.
HPV causes what process in ipithelial cells?
Koilocytosis--vacuolizatoin of epithelial cells.
How does HPV promote unwanted cell growth?
E6 and E7 dysregulate the cell cycle.
Staph aureus virulence factors?
Surface proteins (adherance), enzymes that degrade host proteins, hemolysins (kill cell membranes), exfoliateive toxins, enterotoxins, superantigens.
characteristic Staph aureus inflammation?
Pyogenic local destructive inflammation.
Staph that infects catheterized, prosthetic heart valve, or IV drug users?
Staph epidermidis
Staph that causes UTI?
Staph saprophyticus.
All the things strep A (pyogenes) can cause?
Pharyngitis, scarlet fever, erysipelas, impetigo, rheumatic fever, TSS, necrotizing fascitis, glomerulonephritis.
95% of people infected with CMV are ________.
Asymptomatic
CMV infections in infants produces what disease? CMV in immunocompromised produces what disease?
Cytomegalic inclusion disease. Disseminated CMV (life threatening)
Features of Cytomegalic inclusion disease (in infants)?
Hemolytic anemia, jaundice, hepatosplenomegaly, pneumonitis, deafness, chorioretinitis, brain damaged, Thrombocytopenia.
Features of disseminated CMV infection?
Life threatening. Lung, GI, retina primarily involved. focal necrosis and little inflammation.
Histologic CMV?
Cellular enlargemnt, large purple intranuclear inclusions surrounded by clear halo with small basophilic cytoplasmic inclusions.
How is VZV transmitted and how does it spread?
Aerosols; hematogenously to trunk then head and extremities.
Histology of vesicles and blisters of VZV?
Vesicles have epithelial cell intranuclear inclusions; blisters are identical to HSV.
Where does Herpes zoster (shingles) come from?
VZV latent in DRG infecting sensory nerves.
HBV is what kind of virus? Causes chronic or acute hepatitis?
DNA of hepadnavirus family. Causes both acute and chronic
How is HBV transmitted?
Percutaneously, perinatally and sexually.
Why does HBV stay in the blood for so long?
Lots of mutations due to it being synthesized by reverse transcription of RNA template (no proof reading).
How does HBV damage the liver?
Immune response kills liver, the virus does not.
What determines if a person is a carrier of HBV or not?
cytotoxic T-cell immune response.
Histology of chronic HBV infection?
Lymphocytic infalmmatino, hepatocytic apoptosis; can lead to cirrhosis and increased risk for hepatocellular carcinoma.
Three viruses that cause cancer?
EBV, HPV, HTLV-1
Infectious mononucleosis symptoms.
fever, sore throat, generalized lymphadenopathy, hepatosplenomegaly, and VERY high WBC count.
Progression of EBV virus infection?
Begins in naso/oropharygeal epithelial cells, infects B cells (the reserivoir), T-cells kill the infected B cells.
Histology of lymph nodes in EBV infection?
Increased T cells and Reed-Sternburg-like cells (large binucleate cells).
EBV can lead to what cancers?
B-cell lymphoma (in immunocompromised), Burkitt's lymphoma (8:14 translocation on c-myc of heavy chain)
Histology of HPV?
Koilocytosis- Perinuclear vacuolization of epithelial cells.
Mechanisms of HPV's promotion of cell growth?
E6 and E7 dysregulate the cell cycle.
Staph aureus virulence factors?
Adhesion proteins, enzymes that degrade host proteins; toxins: hemolysisns (damage membranes), exfoliative toxins, enterotoxins, superantigens.
Which staph attacks those with prostetic heart valves and IV drug users?
Staph epidermidis.
Which staph frequently causes UTIs?
Staph saprophyticus
Two beta hemolytic streps?
Pyogenes (A), agalactiae (B)
Strep pyogenes can cause...
pharyngitis, scarlet fever, erysipelas, impetigo, rheumatic fever, TSS, necrotizing fascitis, glomerulonephritis.
Strep agalactiae colonizes where?
The vag.
Strep agalactiae can cause ____
Chorioamnionitis in pregnancy and neonatal sepis and meningitis in neonates.
Alpha hemolytic strep includes...
Strep pneumoniae, Viridians (including s. mutans).
Strep. pneumoniae can cause...
Adult community-acquired pneumonia and meningitis.
Strep viridians can cause...
where do you find strep viridians?
Dental caries (S. mutans) and endocarditis.

Normal flora of the mouth.
enterocci can cause...
endocarditis and UTIs.
Strep virulence factors?
Capsule (group A), M-proteins inhibit the alternate pathway of completment activation (S. pyogenes), pneumolysis destroy membrane and damage tissue (S. pneumonia)
Lifecycle of C. diphtheriae? What organs does it affect?
Colonizes oropharynx and fires off exotoxins to damage the heart, nerves and other organs.
Virulence factors of C. diphtheriae and what they do?
B fragment facilitates entry of A subunit. A subunit blocks protein synthesis via ADP ribosylation.
Listeria Monocytogenes is gram pos or neg?
Pos.
Who does Listeria infect?
Elderly , immunosuppressed, pregnant women and their fetus.
What causes granulomatosis infantiseptica?
Listeria Monocytogenes infecting a fetus.
What does listeria cause?
Meningitis and sepis in elderly, immunocompromised and pregnant ladies.
How does listeria infect cells?
Binds E-cadherin to stimulate phagocytosis, then uses listeriolysin O and phospholipases to excape phagosome and cytoplasm. Then ActA propels the bacteria into adjacent cells.
three classes of B. anthracis infection.
cutaneous, Inhalational, Gastrointestinal.
Signs of cutaneous antrhax infection.
Painless, pruritic papules leading to vesicles and then to black eschar.
Signs of resp. antrhax infection.
Rapid sepsis, shock, death.
Signs of GI antrhax infection.
Severe blood diarrhea and often death.
Anthrax toxins and how they induce damage.
Edema factor - converts ATP to cAMP leading to cellular water efflux.
Lethal factor- protease that estroyes MAP kinase kinase, killing cells
Histology of anthrax-infected cells?
Necrois, neurto and macrophages, and large rectangular extracellular bacteria chains.
Nocardia is what kind of bacteria?
Aerobic Gram-positive in branches. (also stains with modified acid fast stains-Fite-Faraco stain)
Nocardia asteroides causes what?
Opportunistic indolent resp infections, often with CNS infection.
Histology of Nocardia asteroides infected cells.
Granulation tissue and fibrosis. branching and can be stain with modified acid-fast (Fite-Faraco stain).
Neisseria are what kind of bacteria?
Aerobic, gram neg, dipococci
N. Meningitidis affects which age group?
5-19 year olds, esp in those w/ terminal complement deficiencies.
N. Gonorrhoeae symptoms in males, females, and neonates?
Males- Urethritis

Females- usu. asymptomatic; can lead to PID, infertility and ectopic pregnancy.

Neonates- Blindness and rare sepsis.
How do Neisseria evade immune responses?
Expression of alternative genes for adhesive pili and OPA proteins.
Symptoms of Bordetella pertussis?
Paroxysm coughs, laryngotracheobronchitis, mucosal erosions, mucopurulent exudate, lymphocytosis.
Pseudomonas aeruginosa usually affects what 3 groups of people?
CF, burn victims, neutropenia.
In CF patients, how does pseudomonas aeruginosa evade immune responses?
It secretes exopolysaccharide (alginate) forming a protective biofilm.
What can Pseudomonas aeruginosa do to neutropenics?
Tissue necrosis via vascular invasion and thrombosis.
What causes plague?
Yersinia pestis.
what causes iletis and mesenteric lymphadenitis?
Yersinia enterocolitica and yersinia pseudotuberculosis.
symptoms of the plague?
Lymph node enlargement (buboes), pneumonia, sepsis, tissue necrosis, neutrophilic infiltrate.
What causes chancroid (soft chancre)? Symptoms?
Hemophilus ducreyi. Ulcerative genital infection.
How do you get Granuloma inguinale?
STD caused by calymmatobacterium donovani.
How does granuloma inguinale progress?
Starts as a papule on genitalia (or mouth/pharynx) then ulcerates and granulates into SOFT PAINLESS mass. Can cause urethral, vulvar or anal strictures.
Histology of Granuloma inguinale?
Pithelial hyperplasia at ulcer borders with neutrophils.
What cells do M. tuberculosis infect?
Macrophages that should be kill by T-cells 2-4 weeks later.
First exposure to TB causes what?
95% asymptomatic, 5% have lobara consolidation, hilar adenopathy and pleural effusion; rarely spreads via lymph-->miliary.
Symptoms of secondary TB (after latent TB is reactivated)?
Cavitation in apex of upper luns, low fever, night sweats, weight loss.
Appearance of primary and secondary TB?
Primary- Lung and LN granulomas called Ghon complexes.

Secondary-Circumscribed focus of caseation can heal with fibrosis.
What population and where in the body do you find Mycobacterium avium-intracellulare complex?
Immunocompromised folks; widley disseminated throughout the body.
What organism causes leprosy?
Mycobacterium leprae.
How does leprosy spread throughout the body?
Spreads via the blood after being phaged by monocytes or alveolar macrophages.
Two types of leprosy and symptoms?
Tuberculoid- insidious dry scaly skin lesions w/o sensation, peripheral nerve involvemnet.

Lepromatous- Disfiguring,Perineural macrophage and Schwann cell invasion.
What determines if a leprosy infection will be tuberculoid or lepromatous?
Tuberculoid- T-helper 1 response (TNF-gamma)
Lepromatous- ineffective T-helper 2 response.
Name the spirochetes.
Syphilis (treponema pallidum), Borrelia recurrentis (relapsing fever), Lyme (Borrelia burgdorferi)
Primary syphilis symptoms.
3 weeks after sexual contact, firm painless raised lesion (CHANCRE) at infection site. Self-healing. Lesion demonstrates endarteritis.
who gets secondary syphilis?
75% of those who don't treat their primary syph.
secondary syphilis symptoms?
Mucocutaneous lesions, lymphadenopathy, fever, malaise, weight loss.
Who gets tertiary syphilis?
1/3 of untreated infected pts. >5 years later.
Tertiary syphilis symptoms?
CV syphilis- aortitis (endarteritis of vasa vasorum), aortic root dilation, aneurysm, and aortic valve insufficiency.

Neurosyphilis- meningovascular disease, tabes dorsalis, brain parenchymal disease, or protein, WBCs, low glucose in CSF.
When do you see gummas?
In benign tertiary syphilis.
congenital syphilis symptoms?
Death 25%, nasal discharge, skin sloughing, hepatomegaly, skeletal abnorms. Later- notched incisors, deafness, blindness (Hutchinsons triad).
How is replapsing fever transmitted?
Louse transmit Borrelia recurrentis (epidemic). Ticks transmit other types of borrelia (endemic).
What causes the relapses in replapsing fever?
Variation of the surface proteins of Borrelia
Symptoms of relapsing fever/
Chills, fever, HA, DIC, multiorgan failure.
Lyme dz cause by and transmitted by...
Borrelia Burgdorferi from ixodes ticks
Progression of Lyme dz symptoms.
1. erythema chronicum migrans (bulls eye), fever, Lymphadenopathy.

2. Hematogenous spread; skin lesions, LNopathy, joint and muscle pain, arrhythmias, meningitis.

3. Years later; encephalitis, destructive arthritis.
What does the oral anaerobe Fusobacterium necrophorum cause?
Lemierre syndrome.
What's Lemierre syndrome?
Infection of lateral pharyngeal space with septic jugular vein thrombosis. Caused by Fusobacterium necrophorum.
What anaerobe causes Bartholin's cysts abscess and tubo-ovarian abscesses?
Prevotella species often mixed with E. coli and S. agalactiae.
What ususallly causes head and neck abscesses?
Oral flora--Prevotella, Porphyromonas, mixed with Staph and Strep.
What usually causes abdominal abscesses?
Bacteroides fragilis, Peptostreptococcus, Clostridium, E. coli
Clostridium perfringens and C. Septicum cause...
Cellulitis, muscle necrosis in wounds (GAS GANGRENE), food poisoning, small bowel infection.
Histology of gas gangrene?
Infarct w/o inflammatory cells.
How does Clostridium tetani cause tetany?
Tetanospasmin block GABA, an inhibitory neurotranmitter.
How does Clostridium botulinum causes flaccid paralysis?
Binds to motor neuron gangliosides, and cleaves synaptobrevin, blocking Ach release.
What bacteria causes pseudomembranous colitis in antiboiotic-treated pts.?
Clostridium difficle's cytopathic effects.
What causes trachoma? What does it cause?
Chlamydia trachomatis (serotypes A, B, C).

An ocular infection in children.
Life cycle of Clamydia trachomatis?
Elementary body (EB) is the infective particle that transforms into the reticulate body (RB) inside endosomes.
Where does C. trachomatis reside in the body.
In endosommes (an obligate intracellular bacteria).
Symptoms of Chlamydia?
Frequently asymptomatic; epididymitis, prostatitis, PID, pharyngitis, conjunctivitis, perihepatic inflammation, proctitis.
What causes lymphogranuloma venereum?
Chlamydia trachamatis.
Symptoms of lymphogranuloma venereum?
Genital lesions with granulomatous and neutrophils. Caused by C. trachomatis.
Three disease Richettsiae cause
Typhus, spotted fever, ehrlichiosis.
What causes epidemic typus?
Rickettsia prowazekii
Typhus symptoms.
Rash w/ small ehmorrhages to skin ncecrosis and gangrene and internal organ hemorrhages.

CNS typhus- nodules w/ microglial proliferation
Where do Typhus and spotted fever organisms proliferate?
Endothelial cells causesing vessel necroisis.
Ehrlichiosis results from _____ infecting _____.
Anaplasma phagocytophila or Ehrlichia ewingii infecting neutrophils, or
Ehrlichia chaffeensis infecting macrophages.
Symptoms of Ehrlichiosis
Fever, HA, malaise, resp insufficiency, renal failure, shock.
Candida is normally found...
On skin, mouth, GI.
Candida can cause _______ in people with normal immunity.
Vaginitis (esp. in preganancy), diaper rash, oral thrush.
Candida can cause _____ in immunodeficient.
Mucocutaneous candidiasis (in people with hypoparathyroidism, hypoadrenalism, hypothyroidism.

neutropenic pts.- Invasive candidiasis spread hematogenously causing microabscesses.
What does Cryptococcus neoformans do to healthy people and the immunosuppressed?
Healthy - Solitary pulmonary granuloma

Immunosuppresed- Small cysts in gray matter of brain, meningoencephalitis in immunosuppresed and pts. w/ lupus, sarcoidosis.
Who are the infectious molds?
Aspergillosis, Zygomycosis (mucomycosis).
Aspergillus + peanuts = ?
Can create AFLATOXIN leading to liver cancer.
Pulmonary lesions leftover from TB, bronchiectasis, infarcts, abscesses can be colonized by...
Aspergillus fumigatus, creating aspergillomas
What does aspergillus do to immunosuppresed?
Necrotizing pneumonia (target lesions), thrombosis; can lead to hemmorrhage and infarction on necrotizing inflammation.
Aspergillus + neutropenia =
sinusitis, pneumonia, Disseminated aspergillus.
Asperguillus in previously healthy people leads to...
An allergic mold.
Zygomycosis affects what kind of patients?
Neutropenic, and ketoacidotic diabetics.
What causes zyomycosis?
Zygomycetes (Mucor, Absidia, Rhizopus, Cunninghamella). Along with neutropenia, ketoacidosis.
What do zygomycetes do?
Can spread from nasal sinues to orbit or brain; can invade arterial walls causing nerosis.
What organism causes malaria?
Anopheles misquitos transmit: Plasmodium falciparum causes the most severe, vivax, ovale, and malariae cause less servere types.
How does P. falciparum cause tissue ischemia?
Infected RBCs adhere to endothelium, creating vascular occlusion.
What organs are especially involved in malaria?
Splenic occlussion and hepatic enlargement (with Kupffer cells), vascular occlusion leads to hemorrhage and ischemia of the brain.
Three condition that protect against malaria?
HbS, Hemoglobin C traits limit malaria proliferation. Some blacks lack the required duffy RBC antigen.
How do you get babesiosis?
Ixodes ticks trasmit Babesia microti.
Babesiosis symptoms?
Fever, hemolytic anemia, esp. in debilitated and splenectomized.
What does Babesia microti infect?
RBCs (thus the hemolytic anemia), creating the tetrads in RBCs.
Sandflies transmit..
Leishmania species
Leishmaniasis symptoms?
Can be cutaneous or mucocutaneous; mild rashes to disfiguring lesions.
Where do leishmanias live in the body?
in acidic pagolysosomes
Tsetse flies transmit..
African Trypanosomiasis.
Symptoms of Trypanosomiasis?
Chancres at bite site, fevers, LNopathy, splenomegaly, brain dysfxn (sleeping sickness), cachexia, death.
Where do Trypanosomas brucei proliferate?
In the blood (and in macrophages).
Chagas causative agent?
Trypanosoma Cruzi from triatomids ("kissing bugs").
What activates T. Cruzi?
acidic phagolysosomes
Symptoms of Chagas dz?
Years after fever, 20% develop cardiomyopathy, arrhythmias, myenteric plexus damage leading to colon and esophageal dilation.
Who are the Metazoa?
Strongyloidiasis, tapeworms, trichinosis, schisto, filariasis, Onchocerciasis.
Life cycle of the strongyloidiasis.
Pentrate the skin, travel in the blood to lungs, ascend trachea, get swallowed, colonize GI, create eggs.
symptoms of strongyloidiasis.
GI symptoms (they invade intestinal mucosa), immunocompromised get disseminated strongyloides.
Taenia solium (tape worms) symptoms (pork or human).
T. saginata (beef) or Diphyllobothrium latum (fish)?
Can penetrate the gut wall and disseminate to encyst in brain and other organs.

Stay in GI.
what causes Hydatid disease?
Ingestion of echinoccal eggs (Echinococcus granulosus)from dog or fox feces, eggs hatch in duodenum and invade the liver, lungs, and bones forming cysts.
How do you get trichinosis?
Pig and bear meat.
symptoms of trichinosis infection?
Adults spread to muscle causing fever, myalgias, eosinophilia, periorbital edema. Increased gut motility.
Histology of trichinosis?
Membrane-bound vacuoles in myocytes surrounded by eosinophils.
How is Schistosomiasis transmitted? Life cycle?
Freshwater snails; penetrate skin and settle in pelvis or portal venous systems, releasing eggs in stool and urine.
Histology of Schistosomiasis?
Eosinophil-rich granulomas and fibrosis in liver.
Causes of Lymphatic filariasis?
How is it contracted?
Wucheria bancrofti (90%), Brugia malayi.
Mosquitoes.
Black flies transmit...
Onchocerciasis.
Symptoms of Onchocerciasis. Lifecyle?
Pruritic dermatitis and blindness. Nematodes mate in the dermis producing a nodule (onchocercoma). Eggs accumulate in the skin and eyes. (black fly)
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