Lecture 13 & 14: infectious diseases of the hematopoietic system

Bartonellaa henselae

•Short, fastidious Gram-negative rods; difficult to culture

•Facultative intracellular pathogens; infect CD34+ cells

•Transmitted by bites or scratches from infected cats or fleas

transmission of bartonella hensseae

-cutaneous lesion at site of inoculation---> regional lymphadenopatahy

presentation of bartonella henselae

bartonella henselae

________ can be a cause of culture nengative endocarditis

Bacillary angiomatosis

this complication of bartonella henselae primarily presents in AIDS pts

bacillary angiomatosis

angioproliferative cutaneous lesions associated with B. henselae

-bone lesiions

-peliosis

Bartonella bacilliformis

-bartonella endemic to the andes mountains

-transmitted by female sand fly

-most frequently in children

south american bartonellosis

AKA Carrionn's disease

-acute phase oroya fever to chronic phase verruga peruana with skin lesions

pattern of disease progression of Carrion Disease (bartonella baciilliformis)

Verruga peruana

-chronic form of Carrion's disease, present as skin lesion

rocha-lima inclusions

characteristic lesions of verruga peruana on histology

toxin inactivating an inhibitory G protein, activates adenylate cyclase, increasing cAMP

Pertussis toxini causes lymphocytosis via

Bordatella pertussis

lymphocytosis indicating

ananplasma phagocytophilum

an obligate intracellular gram-negative bacteria, forms morulae

•Causes human granulocytic anaplasmosis (HGA)

new england, minnesota, wisconsin

geographic distribution of anaplasma phagocytophilum

Ixodes tick

principle vector of anaplasma phagocytophilum

-acute illness with flu-like symptoms

-•Usually less severe than E. chaffeensis infection

presentation of anaplasma phagocytophilum

Ehrlichia chaffeensis

•Obligate intracellular gram-negative bacteria

•Causes human monocyte ehrlichiosis (HME)

•Amblyomma americana (lone star tick)

prinicipal vector of Ehrliichhia chaffeensis

Ehhrlichia chaffeensis

•More likely to be severe compared with Anaplasma phagocytophilum infection

-may see rash and neuro symptoms

Ehrlichia ewingii

•Obligate intracellular gram-negative bacteria

•Infects granulocytes and causes ehrlichiosis

Amblyomma americanum (lone star tick)

principle vector of Ehrlichiia ewiingii

•Large anaerobic, gram-positive, spore-forming rod

genome of Clostridium perfingens

C. perfringens

-present as myonecrosis, usually due to trauma

-gas in the soft tissue

•hemolysis and interferes with neutrophil differentiation

May lead to disseminated intravascular coagulation and acute kidney injury

the alpha toxin of C. perfringens leads to

increased spherocytes and RBC ghosts (black arrow), and neutrophiils toxic granulation

blood smear of C. perfringens show

Human T-cell lymphotrophic virus

•Transmitted via breast-feeding, blood, or sexual contact

•Women 2x more likely to be infected

adult T cell leukemia-lymphoma

presents as:

•Widespread involvement of lymph nodes, peripheral blood, and/or skin

•Hypercalcemia, lytic bone lesions, skin lesions

CD4+

human T cell lymphotrophic viruss infect these cells

Tax proteini

in HTLV-1, this viral protein induces infeted cells to produce CCL22, which attracts CCR4-expressiinig CD4 cells

Human T-cell lymphotrophic virus

associated with flower cellss in peripheral blood

CD4+, CD25+, CD7-, CD8-

immunophenotypes of HTLV

-mono

-oral hairy leukoplakia, lymphoproliferative disorders, several malignancies

what are the various presentations of EBV

-EphA2 receptor of epithelial cells

-taragets B cells MHC class II protein, binds CD21

host cell receptor and target of EBV

heterophile antibodies, mostly IgM

antibodies produced by EBV infection of B cells

downey cells

-reactive lymphocytes that appear to hug RBC

-appear 1-3 weeks after onset of EBV

Lymphocytic infiltration

what causes the hepatosplenomegaly associated with EBV?

•lymphocytosis, atypical lymphocytes, elevated aminotransferases

hematologic findings associated with mononucleosis

Burkitt lymphoma

•Rapidly growing tumors in jaw or facial bones, primarily in children in malaria endemic regions

Burkitt lymphoma

histology shows starry sky pattern of histiocytes dispersed through basophilic tumor cells

•May include unexplained anemia, thrombocytopenia, or leukopenia

•Elevated LDH (tumor lysis syndrome)

•↑ EBV viral load

hematologic findings of post-transplant lymphoproliferative disorder

CMV infection

presents like mono: cervical lymphadenopathy, tonsillitis less common than with EBV

•Heterophile antibody negative, owl's eye inclusions in infected cells, CMV IgM or IgG positive

hematologic findings associated with CMV

rocky mountain wood tick in mountains of western US and Canada

coltvirus is transmitted by

symptoms begin most commonly in May-July

most common season of coltvirus infection

•Biphasic fever, chills, headache, myalgia/arthralgia, fatigue, sometimes rash

•Leukopenia with both lymphocytes and neutrophils

presentation of coltivirus

parvovirus B19

the agent of erythema infectiosum

parvovirus B19

virus that can cause a transient aplastic crisis in pts with hematologic abnormalities--> severe anemia and related complications

lytic infection of erythroid precursors

cause of aplastic anemia in pts with parvo

parvovirus B19

-virus causing hydrops fetalis in pregnant women (abnormal fluid in fetal soft tissues)

-virus binds to P blood group antigen found on RBC and precursors

-viral replication leads to cell destruction, inhibiting erythropoiesis

pathogenesis of parvovirus B19

infected monocytes transport virus to muscle, joints, liver, and brain

pathogenesis of chikungunya virrus

Aedes mosquito

chikungunya virus is transmitted by

•Acute febrile illness, rash, arthralgia +/- swelling

•Some patients develop chronic arthritis

presentation of chikungunya virus

zika virus

virus infects neural cells and many other cell types

•Transmitted by Aedes mosquitoes, sex, maternal-fetal

transmission of zika virus

-most are asymptomatic

•Low grade fever, rash, arthralgia, conjunctivitis

•Strong association with Guillain-Barré syndrome

•Congenital infection can cause microcephaly and neurodevelopmental abnormalities

presentation of zika virus

anopheles mosquitoes

Plasmodium spp. is transmitted by

•Febrile illness with nonspecific flu-like symptoms

•Repeated bouts of chills and fever

•May have anemia and palpable spleen

presentation of plasmodium spp.

Hemozoin

plasmodium parasites make

when infected RBCs burst at the same time

what causes paroxysms in plasmodium inffection?

Babesia spp.

makes a maltese cross appearance of RBCs

ixodes ticks; most cases in the northeast

transmission of babesia

NO!

plasmodium does

do babesia deposit hemozoin in RBC?

ARDS

most common complication of babesia

sandflies

Leishmania donovani is transmitted by

-cutaneous leismaniasiis: painless ulcer

-mucocutaneous

-visceral/black fever

presentation of Leishmania donovanii

macrophages

leishmania replicate inside host __________

Visceral Leishmaniasis

•Parasites spread hematogenously to cells in liver, spleen, bone marrow, intestinal lymph nodes

Bartonella henselae

•cat scratch disease, bacillary angiomatosis

Bartonella bacilliformis

•Oroya fever, verruga peruana

bartonella quintana

trench fever

Anaplasma phagocytophilum

•human granulocytic anaplasmosis

Ehrlichia chaffeensis

•human monocyte ehrlichiosis

Ehrlichia ewingii

ehrlichiosis

Clostridium perfringens

•foodborne illness, myonecrosis

HTLV1

•adult T cell leukemia-lymphoma, tropical spastic paraparesis

parvovirus B19

•erythema infectiosum, hydrops fetalis, transient aplastic crisis

zika virus

•milder dengue-like illness, congenital infection causes microcephaly

chikungunya viruss

•flu-like illness with rash and joint pain

hemolytic anemia

infections causing

lymphocytosis

infections causing

ehrichial/anaplasma

infections causing leukopenia

granulocyte

infected host cell off a. phagocytophilum

anaplasmosis: ixodes tick

ehrlichiosis: amblyomma americanum (lone star tick)

vector of Anaplasmosis vs ehrlichiosis

monocytes, macrophages

infected host cell of E. chaaffeensis

chikungunya

virus associated with SEVERE joint pain mainly in arms and legs, high ffeverr

zika virus

virus associated with red and white patchy skin rash

dengue viirus

virus associated with higher fever and more severe muscle pain