Hematologic Infections Flashcards

1
Q

Hemophagocytic lymphohistocytosis (HLH)

A

macrophages are activated by cytokines or EBV → attack RBCs

(IFN-g, IL-1, IL-2, IL-6, TNF-a)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Major signs and symptoms of hemophagocytic syndrome (HLH)

A
  1. Splenomegaly
  2. Jaundice
  3. Fever
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

In HLH, MF will phagocytize ______ (3).

A
  1. erythrocytes
  2. leukocytes
  3. platelets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

In HLH, infections are caused by bacteria, fungi, parasites, viruses. It may also be associated with ____(2).

A
  1. Collagen-vascular disease
  2. Malignancies
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

HLH will show _____ bone marrow with active _____.

A
  • hypocellular
  • hemophagocytosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

If you suspect HVH, what sample would you take at the visit (in office)?

A
  1. throat & rectal swabs (viral)
  2. fungal scrapings
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

If you suspect HVH, which labs would you order (6)?

A
  1. EBV
  2. CMV
  3. HIV
  4. HSV
  5. CA screen (T cell lymphoma)
  6. Blood & urine cultures
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

If you suspect HVH, what tests would you order?

A

Chest XR for Tb

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Which 2 gram negative rods can cause HLH?

A
  1. Brucella sp.
  2. Rickettsia sp.
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What characteristics do Brucella sp. share with Rickettsia sp.?

A
  1. Gram -
  2. rods
  3. aerobic
  4. intracellular
  5. both may → HLH
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Virulence of brucella sp. is due to ______.

Virulence to rickettsia sp is due to ______.

A
  • O-antigen on LPS
  • phospholipase (destroys membrane)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

While HLH may be caused by Brucella sp. or Rickettsia sp. which is acquired from unpasteurized milk?

A

Brucella sp.

(Rickettsia sp. from ticks)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Brucella sp. require on the __________ in order to activate their virulence factor genes

A

acidic environment of the phagolysosome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Brucella activate virulence factors within the phagolysosome and then move on to the spleen, liver, bone marrow, lymph nodes and kidneys to form _______.

A

granulomas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

______ is the preferred stain for Rickettsia sp.

A

Geimsa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Rocky Mountain Spotted Fever is endemic to the ______ U.S.

A

western

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Pathological manifestations of Rocky Mountain Spotted Fever are found in the ______.

A

small blood vessels

(epithelial lining damage → thrombi & vasculitis in skin, lungs, spleen, heart, liver, kidney)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Rocky Mountain Spotted Fever may lead to _____.

A

DIC

(severe endothelial damage → systemic activation of coagulation cascade)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What labs are ordered if Rocky Mountain Spotted Fever is suspected?

A
  1. Pt/PTT
  2. D-dimer (⇡)
  3. Fibrinogen (⇣)
  4. Hct
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Epidemic typhus is caused by ______.

A

Rickettsia prowazekii

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Epidemic typhus is transmitted through ______.

A

louse feces

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Epidemic typhus: s/sx

A
  1. maculopapular rash
  2. hypotension, vascular collapse

(HA, fever, splenomegaly)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Anemia: general mechanisms

A
  1. ⇣ RBC production
  2. ⇡ RBC destruction
  3. Blood loss
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

MC blood smear presentation for iron deficiency anemia

A
  1. hypochromic
  2. microcytic

(decreased iron or transferrin levels, stores are normal or elevated)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

macro/microcytic describes _______ (lab value); while hyper/hypochromic describes _____ (lab value)

A
  • MCV
  • MCHC
26
Q

Increased hepcidin levels in response to cytokine release will → decreased _______ levels

A

serum iron

(during inflammation → 100x increase)

27
Q

hepcidin is a key regulator of _____.

A

iron metabolism: GI absorption & release from MF via RBC destruction in RES

28
Q

Hepcidin is a negative regulator of iron ______ (3).

A
  1. Absorption in SI
  2. Transport across placenta
  3. Release from MF
29
Q

During inflammation hepcidin levels increase by 100x → negative regulation of iron →

A

lower EPO → suppressed hematopoiesis

30
Q

Which microbe causes the most severe malaria?

A

Plasmodium falciparum

31
Q

How is malaria acquired from plasmodium falciparum?

A

sporozoites in mosquito saliva → human blood → become merozoites in liver → merozoites invade RBCs → replicate & lyse

32
Q

_____ is the gold standard for lab diagnosis of P. falciparum.

A

Geimsa stain

33
Q

Why does P. falciparum cause splenomegaly?

A

eats Hb → disrupting cytoskeleton → sickle cell shape → clogs splenic vasculature

34
Q

What distinguishes P. falciparum from the other plasmodium sp?

A

infects all erythrocytes; other forms infect old or young

35
Q

What is the distinguishing feature of Plasmodium vivax on blood smear?

A

Schuffner’s dots (small purple-red granules on Wright’s stain)

36
Q

Which labs would you order if you suspect malaria (3)

A
  1. Rapid test: dipstick or cassette
  2. PCR (molecular)
  3. Serology: IFA, ELISA
37
Q

2 hosts of babesiosis?

A
  1. white footed mouse (Peromyscus leucopus)
  2. deer tick (Ixodes Dammini)

(humans = accidental hosts)

38
Q

Babesia sp. are endemic to the _______ U.S.

A

NE (NY, MA)

(note that tetrad formation)

39
Q

Diagnosis of babesiosis is done via _____ or _____

A
  1. Direct blood smear: tetrad formation
  2. IFA: Ab against Babesia microti
40
Q

At what point in the life cycle is babesia introduced to humans?

A

sporozoites

(may also be acquired via blood transfusion)

41
Q

Which microbe produces lecithinase which binds to RBC → lysolecithin?

A

clostridium perfringens

(lyses leukocytes & muscle cells, too)

42
Q

Which microbe produces alpha-toxin → massive hemolysis & bleeding & myocardial dysfunction?

A

clostridium perfringens

43
Q

Other than lecithinase & alpha-toxin, what are 2 other virulence factors of C. perfringens?

A
  1. Theta-toxin (pore-forming hemolysin)
  2. hydrogen peroxide → damages RBC membranes
44
Q

Which microbe that causes hemolytic anemia lacks a cell wall and is resistant to penicillin?

A

Mycoplasma pneumoniae

45
Q

M. pneumniae attaches to the eukaryotic host cell through membrane based receptors in the respiratory tract & RBCs →

A

inhibition of ciliary action of the respiratory tract & cell necrosis (toxins)

46
Q

What is cold autoimmune hemolytic anemia?

A

acquired autoimmune hemolytic anemia: IgM attacks I Ag on RBC → transient agglutination in fingers, ears, nose

(areas below normal body temp)

47
Q

Agents that may cause cold-autoimmune hemolytic anemia (5).

A
  1. EBV (mono)
  2. Legionella sp.
  3. Mumps, rubella
  4. CMV
  5. Measles vaccine
48
Q

Rubella (aka German measles) is part of the ______ family.

A

Togaviridae

(same as Eastern & Western Equine Encephalitis)

49
Q

Rubella characteristics

A
  1. +ssRNA
  2. enveloped
50
Q

Rubella is transmitted via ______.

A

respiratory droplets

(replicates in nasopharynx & lymph → viremia to other tissue)

51
Q

Rubella manifestation in children

A
  1. Hemorrhagic manifestation: GI, cerebral
  2. Low platelet, vascular damage
  3. thrombocytopenia purpura
52
Q

Donath-Landsteiner Ab

A

IgG Ab that react w/RBCs in the cold (below body temp) → cold autoimmune hemolytic anemia

53
Q

Microorganisms can trigger cold-autoimmune hemolytic anemia against the _____.

A

P antigen on RBCs

(varicella, mumps, measles, flue, adenovirus CMV, EBC, M. pneumoniae)

54
Q

Haemophilus influenzae type b meningitis is an example of _______ reaction.

A

antigen-antibody complex (binds to RBC)

55
Q

Polyagglutination is a rare form of hemolysis where the _______ of infectious agents affect RBCs by exposing _____.

A
  • metabolic products
  • surface Ag not normally present → Ab produced against these newly found Ags

(i.e. neuraminidase from enteric bacteria)

56
Q

______ (2 infectious agents) that can lead to blood loss from disruption of the gastrointestinal or genitourinary mucosa.

A
  • H. pylori
  • Helminthic infections (nematodes & trematodes)
57
Q

H. pylori characteristics (4)

A
  1. spiral-shaped
  2. gram (-)
  3. urease +
  4. flagella that drill into mucosa
58
Q

List the 2 hookworms that penetrate the skin → circulation → lungs → cough up and swallow.

A
  1. ancylostoma duodenale
  2. necator americanus
59
Q

In hookworm infestation, blood loss is due to feeding worms. _______ anemia develops.

A

microcytic, hypochromic

60
Q

Carries of the _______ (worm) have vitamin B12 deficiency.

A

diphyllobothrium latum (cestode): fish tapeworm

(scolex shaped like a lance)