Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

micro_db > oportunstic infections > Flashcards

oportunstic infections Flashcards

1
Q

what are the opportunistic pathogens?

A
  • -usually benign but have the ability to cause disease in an immunocompromised host (e.g., patients with AIDS or after chemotherapy)
  • -Examples of opportunistic infections: oral candidiasis, vaginal yeast infection, cytomegalovirus infection, cryptococcal meningitis, pneumocystis jirovecii pneumonia, toxoplasma encephalitis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

opportunistic pathogens have high virulence. True/False

A

False
of low intrinsic virulence that are not normally harmful: e.g.
– Coagulase-negative staphylococci
– Aspergillusfumigatus

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

what are the pathogens commonly associated with asplenia and hypogammaglobulinemia

A

S. pneumoniae

H. Influenzae

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

what pathogen has increased the risk of causing disease in complement deficiency?

A

Neisseria spp

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

impaired cell-mediated immunity increases the risk of what infections?

A

1) intracellular bacteria (listeria)
2) viruses
3) fungi
4) parasites

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

what is the immunocompromized state?

A

A state of reduced activation and/or efficacy of the immune system. Etiologies include congenital immunodeficiency disorders, AIDS, diabetes mellitus, chronic alcoholism, certain neoplasms (e.g., lymphoma), treatment with certain drugs (e.g., corticosteroids, chemotherapeutic agents), and radiation therapy,

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

what is the general vs specific immunocompromised state?

A

1)General term
• any patient compromised by virtue of his/her underlying condition
• e.g. multiple trauma patients in ICU
non-specific

2)Specific term
• A patient with a recognized deficiency of one or more immune parameters
• e.g. neutropenic patient on chemotherapy
refers to specific categories of patients

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

what is the importance of opportunistic infections?

A
  • Increased numbers of immunocompromised patients
  • A significant cause of morbidity & mortality
  • Can be polymicrobial& complex
  • Bacteria often are multi-antibiotic resistant
  • Variable clinical presentation – atypical, fever often absent
  • May be difficult to diagnose
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

what are the features of Opportunist Pathogens

A

i. Low pathogenicity & sometimes ubiquitous, e.g. Pneumocystis jirovecii, Candida albicans, S. epidermidis, P. aeruginosa
ii. They can be part of normal flora, e.g. S. epidermidis, Candida
iii. Adapt to host & circumstances, e.g. biofilm production
iv. Often difficult to completely eradicate / may relapse, e.g. CMV
v. Variable clinical presentation
vi. Absent normal immune response; negative serology

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what is the primary immunodeficiency?

A

Congenital immunodeficiency disorders are characterized by a deficiency, absence, or defect in one or more of the main components of the immune system. These disorders are genetically determined and typically manifest during infancy and childhood as frequent, chronic, or opportunistic infections

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

what are the causes of primary immunodeficiency?

A

– Antibody deficiency syndromes
– Neutrophil dysfunction e.g. chronic granulomatous disease
– severe combined immune deficiency (SCID), complement deficiency states

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

name congential B-cell immunodeficiencies

A

1) Brutton agammaglobulinemia
2) Selective IgA deficiency
3) Common variable immunodeficiency

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

what are the congenital T cell immunodeficiencies

A
  • -DiGeorge syndrome
  • -Job syndrome (hyper-IgE syndrome)
  • -IPEX syndrome
  • -IL-12 receptor deficiency
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

what are the causes of secondary immunodeficiency?

A

– Immunosuppressive therapy: Steroids, chemotherapy
– Malignancy
– Autoimmune disease: Rheumatoid arthritis
– Microbial infection: HIV
– Biochemical abnormalities: Diabetes mellitus, malnutrition
– Asplenia/hyposplenism

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

what anatomical abnormalities increase risk with opportunistic pathogens?

A

1)Barrier problems– intact skin is a key component of the body’s defenses
o e.g. burns
2)Inadequate clearance
o e.g. respiratory tract cilia that are abnormal in structure or function: Primary ciliary dyskinesia
3)Obstruction
o e.g. cystic fibrosis, chronic obstructive pulmonary disease (COPD)
4)Foreign body
o e.g. a central venous catheter

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

list endogenous bacteria that can cause opportunistic infections

A 
•	S. epidermidis
•	S. aureus
•	Gut flora
–E. coli
–Enterococci, including vancomycin-resistant enterococci (VRE)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

list exogenous bacteria that can cause opportunistic infections

A
  • S. aureus, including MRSA
  • Enterobacteriaceae
  • P. aeruginosa
  • Listeria
  • Atypical mycobacteria &M. tuberculosis
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

list viruses that can cause opportunistic infections

A

• Herpesviruses: Latency leading to reactivation
–Herpes simplex virus 1 & 2
–Varicella-zoster virus
–Cytomegalovirus
• Polyomaviruses: Latent in kidney & lymphoid tissue
–JC virusProgressive Multifocal Leukoencephalopathy (PML)
–BK virus(stem cell and renal transplant recipients)
• Parvovirus B19: Can cause profound red cell aplasia
–Persistent infection in immunocompromised/persistent anemia
• Hepatitis B: chronic carriage or reactivation of latent infection

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

what is the PML (progressive multifocal leukoencephalopathy)

A

A fatal disease characterized by multifocal demyelination in the brain. Caused by reactivation of a latent JC virus infection in immunosuppressed patients (e.g., AIDS, hematological malignancies, post-transplant period, use of natalizumab).

20
Q

what is caused by the BK virus?

A

A non-enveloped, double-stranded circular DNA virus of the polyomavirus family that infects the urothelium. BK virus infection is widespread but asymptomatic in the general population. Reactivation of the virus in immunosuppressed patients (especially transplant recipients) can cause polyomavirus-associated nephropathy and/or polyomavirus-associated hemorrhagic cystitis. The name is derived from the initials of the first kidney transplant patient from which the virus was isolated.

21
Q

what fungi cause opportunistic infections

A 
•	Candida spp.
–Mucositis, oesophagitis, candidaemia
•	Aspergillusfumigatus
–	Lower respiratory tract infection
•	Cryptococcus neoformans
–Meningitis or meningoencephalitis
•	Pneumocystis jirovecii –PCP
–Pneumonia
22
Q

list important protozoa that cause opportunistic infections

A

• Toxoplasma gondii
–Cerebral toxoplasmosis
• Cryptosporidium parvum
–Severe diarrhoea

23
Q

define neutropenia

A

A decreased neutrophil count (mild: 1000–1500 cells/μL; moderate: 500–1000 cells/μL; severe: < 500 cells/μ). Most commonly caused by bone marrow damage, which can be drug-induced or due to malignancy or viral infection

24
Q

neutropenia increases the risk of bloodstream infections (BSI) & respiratory infections. True/False

A 
True
Source of microbial invasion of the blood
1)chemotherapy-induced mucositis 
2)breaks in the gastrointestinal lining
  –Bacterial/fungal translocation
3)intravascular lines
25
Q

what is neutropenic fever?

A

Neutropenic fever is an oncologic emergency common in patients receiving chemotherapy. A decrease in a patient’s absolute neutrophil count (ANC) can lead to potentially life-threatening infections, and the risk of serious infection is directly associated with the extent and duration of neutropenia. Because the immune response is impaired in neutropenia, symptoms can be mild and even a low-grade temperature (≥ 38°C) should be considered a fever.

26
Q

what are the common causes of fever in neutropenic patients?

A
  • Gram-positive cocci (e.g. coagulase-negative staphylococci, S. aureus, streptococci/ enterococci) in about 55-60%
  • Gram-negative bacilli (e.g. E. coli, P. aeruginosa) in about 40-45%
  • Fungi such as Aspergillus spp. &Candida spp.
27
Q

what are the common sites of infection in neutropenic sepsis?

A

Oral cavity, the skin, perirectal & genital areas, 20% BSI, lung, indwelling intravascular catheters or other foreign bodies

28
Q

what are the stages of neutropenic fever treatment?

A

Empiric antibiotic therapy should be initiated immediately after two sets of blood cultures have been obtained
Stage 1: include antibiotic with activity against pseudomonas: Piperacillin/tazobactam,+gentamicin
Stage 2:cover G+ pathogens-add vancomycin
Stage 3:anti-fungal: caspofungin
Stage 4: consider anti-viral or PCP treatment: ganciclovir, TMP:SMT

29
Q

The risk of TB is increased in patients with HIV and CD4 count?

A

200-500

30
Q

the risk fo disseminated CMV and MAC increased in patients with HIV and CD4 count?

A

<50

31
Q

this risk of toxoplasmosis is increased in patients with HIV and CD4 count?

A

100

32
Q

the risk of candidiasis and cryptococcosis is increased in patients with HIV and CD4 count

A

<100!!! (corrected)

33
Q

the risk of cryptosporidiosis is increased in patients with HIV and CD4 count?

A

<200

34
Q

The risk of PCP and PML is increased at what CD4 count?

A

<200

35
Q

why premature infants are at increased risk of opportunistic infections

A
  • Malnutrition, low antibody levels
  • Impaired cellular & cytokine response such as interferon
  • Poor migration of mononuclear cells
36
Q

the risk fo which infections is increased in patients with renal transplantation?

A

o Urinary tract infections
o Bloodstream infection
o CMV later 2 - 4 months
o PCP
–Immunosuppressive agents prevent graft rejection
–Examples: cyclosporin, mycophenolate mofetil, tacrolimus
–Lymphopenia, impaired cytokine release

37
Q

what opportunistic pathogens commonly cause disease in premature infants?

A
  • E. coli
  • Group B b hemolytic streptococcus
  • Listeria monocytogenes
  • Candida albicans
  • Herpes simplex
38
Q

burn victims are at significantly increased risk of sepsis with what bacteria?

A

o Pseudomonas aeruginosa

o S. aureus

39
Q

why foreign bodies increase the risk of infections?

A

–Adaptation by pathogen
–Biofilm
–Poor penetration by antibiotics leading to antibiotic resistance
–Developments in devices to reduce this

40
Q

what are the general features of the management of patients with opportunistic infections?

A
  • Repeated and appropriate investigations – to include blood cultures (x3)
  • Many tests may be negative e.g. serological tests due to immunosuppression
  • Specialized tests;
    • High-resolution CT of thorax – pulmonary aspergillosis
    • PCR – CMV,
    • Broncho-alveolar lavage (BAL) for PCP, mycobacterial culture & viral PCR for CMV /HSV etc
    • Logic and rational basis for antibiotic use
    • Remove all devices
41
Q

how PCP infection is confirmed?

A

Broncho-alveolar lavage (BAL)

42
Q

what are the presentations of CMV infection in immunocompromised patients?

A

pneumonitis, gastrointestinal or CNS symptoms

43
Q

in the case of persistent fever in immunocompromised patients what pathogens should be considered?

A
  • -CMV infection
  • -Herpes simplex virus (HSV) and varicella-zoster (VZV)
  • -Respiratory viruses eg. RSV, influenza, adenovirus etc.
  • -Pneumocystis jirovecii (carinii) pneumonia (PCP)
44
Q

what medication is used to treat CMV in immunocompromised patients?

A

ganciclovir

45
Q

what medications are used to treat PCP?

A
  • -Treatment of choice: high‑dose TMP/SMX for up to 3 weeks
  • -Glucocorticoids: add in the case of severe respiratory insufficiency (either PaO2 < 70 mmHg or arterial‑alveolar oxygen gradient ≥ 35 mmHg).
  • -alternatives if allergic to TMP/SMX or treatment of choice is ineffective
    1) dapsone
    2) clindamycin
    3) Intravenous pentamidine (monotherapy)
46
Q

how Invasive pulmonary fungal disease is managed?

A 
•Suspected:
–	e.g. based on HR-CT appearance
–	Empiric Amphotericin B
–	> Broad-spectrum antifungal cover
•Confirmed invasive aspergillosis:
–	Voriconazole is the treatment of choice
–	Prolonged duration
–	Therapeutic drug monitoring
47
Q

what antifungal drug is the treatment of choice of invasive aspergillosis

A

voriconazole

micro_db (18 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions