Healthcare Infection Control Quiz

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Questions and Answers

What is the primary benefit of passive immunization?

It replaces the need for vaccination.

Long-lasting immunity against infections.

Immediate protection provided. (correct)

It requires no medical supervision.

What limitation is associated with the use of passive immunization products?

They have no risk of causing allergic reactions.

Protection is relatively short-lasting. (correct)

They are effective for all types of infections.

They are always obtained from human donors.

Which of the following definitions best describes hospital-acquired infections?

Infections transmitted between patients in emergency departments only.

Infections that occur in the community but are treated in hospitals.

Infections that originate in medical facilities after a patient is admitted. (correct)

Infections that are prevalent in the general population.

What does the term 'infection control' refer to in healthcare settings?

Evidence-based practices to prevent microorganism transmission. Signup and view all the answers

What is a potential risk associated with the use of anti-serum raised in animals?

Development of serum sickness. Signup and view all the answers

Which of the following is an example of chronic inflammation that arises from repeated episodes of acute inflammation?

Chronic pyelonephritis Signup and view all the answers

What histologic hallmark is NOT typically associated with chronic inflammation?

Acute neutrophilic infiltrate Signup and view all the answers

In the context of chronic inflammation, which condition is related to non-infective hypersensitivity?

Rheumatoid arthritis Signup and view all the answers

What type of cell is primarily responsible for the histological feature of a dark, minimal cytoplasm in chronic inflammation?

Lymphocytes Signup and view all the answers

Which of the following conditions might represent a chronic inflammation arising from persistent infection?

Chronic cholecystitis Signup and view all the answers

Which option correctly identifies a condition associated with chronic inflammation through exposure to insoluble particles?

Atherosclerosis Signup and view all the answers

Which characteristic of chronic inflammation contributes to tissue destruction?

Macrophage activation Signup and view all the answers

Which of these diseases is not traditionally considered an inflammatory disorder but is linked to chronic inflammation?

Alzheimer’s disease Signup and view all the answers

Which immune cells are primarily involved in antibody-dependent cellular cytotoxicity (ADCC) by recognizing IgG?

NK cells Signup and view all the answers

What is the primary role of eosinophils when activated by IgE?

Cytotoxic granule release against larger organisms Signup and view all the answers

What is the composition of a conventional T cell receptor (TCR)?

Two chains: alpha and beta Signup and view all the answers

What does TCR stand for in the context of T lymphocytes?

T Cell Receptor Signup and view all the answers

How does the T cell receptor (TCR) recognize its specific antigen?

By recognizing antigenic peptides presented by MHC molecules Signup and view all the answers

What role do CD4 and CD8 play in T cell activation?

They provide supportive signaling for TCR recognition Signup and view all the answers

Which immune cells serve as antigen-presenting cells (APCs)?

Macrophages, B cells, and dendritic cells Signup and view all the answers

Which statement about T cell maturation is correct?

It starts in the thymus and ends in the blood and lymphatics Signup and view all the answers

What is meant by the term 'tolerance' in the context of the immune system?

The unresponsiveness of lymphocytes to self antigens. Signup and view all the answers

Which of the following is NOT a cardinal feature of acute inflammation?

Fever (febris) Signup and view all the answers

What sequence accurately represents the process of inflammation following tissue injury?

Inflammation → Demolition → Healing/Repair → Resolution Signup and view all the answers

Which of the following causes of tissue damage involves a reduction in blood flow?

Ischaemia Signup and view all the answers

What role do neutrophils play in the process of acute inflammation?

They engage in the phagocytosis of pathogens and debris. Signup and view all the answers

Which of the following statements best describes chronic inflammation?

It may involve a prolonged series of tissue reactions. Signup and view all the answers

What is the significance of vascular permeability in acute inflammation?

It allows plasma proteins to leak into the tissue and cause swelling. Signup and view all the answers

What is dystrophic calcification commonly associated with following tissue damage?

Formation of hard lumps detectable on X-rays. Signup and view all the answers

What is the primary function of interferons in the immune response?

Enhancing the adaptive immune response and killing infected cells Signup and view all the answers

Which of the following accurately describes C3 deficiency?

It results in frequent severe bacterial infections and increased infection risk. Signup and view all the answers

Which type of interferon is primarily produced by virus-infected fibroblasts?

Interferon 𝛽 Signup and view all the answers

Which cells are primarily responsible for the cytotoxic effects of the immune system?

Natural killer cells Signup and view all the answers

Which lymphoid organ is primarily involved in the maturation of T lymphocytes?

Thymus Signup and view all the answers

What characterizes the specificity of acquired immunity?

Presence of diverse antigen receptors Signup and view all the answers

Natural killer cells are characterized by which of the following markers?

CD16+ CD56+ CD3- Signup and view all the answers

Which therapy has IFN-𝛼 been effectively used for?

Treatment of hepatitis B and C Signup and view all the answers

What histological feature is typically present in a granuloma associated with tuberculosis?

Acid-fast bacilli Signup and view all the answers

Which type of granuloma is caused by large foreign bodies?

Foreign body granuloma Signup and view all the answers

Which of the following statements regarding Langhans giant cells is correct?

They exhibit a horseshoe arrangement of nuclei. Signup and view all the answers

Which classification corresponds to tuberculosis after initial exposure and sensitization?

Secondary tuberculosis Signup and view all the answers

What is the defining characteristic of miliary tuberculosis?

Distant organ seeding due to the presence of mycobacterium in lymphatics Signup and view all the answers

What defines antibiotics as a class of substances?

Substances that inhibit growth or kill bacteria Signup and view all the answers

Which cell type does NOT represent a form of giant cell seen in granuloma?

Myeloid giant cells Signup and view all the answers

Which of the following statements about the classification of antibacterial agents is true?

One classification method is based on their chemical structure. Signup and view all the answers

Study Notes

Exanthematous Rashes

Enterovirus infections can cause rashes
Parvovirus B19 ("Slapped-cheek rash" or "Fifth disease") causes a rash
Human Herpesvirus 6 (HHV-6) causes roseola infantum
Measles is highly contagious, potentially leading to severe complications like pneumonia.
Rubella can cause congenital rubella syndrome if a pregnant woman is infected

Viral Hemorrhagic Fever

Ebola virus disease is a major source of outbreaks, predominantly in Africa.
A recent West African outbreak involved ~30,000 cases.
Hong Kong is at risk due to its global connections.
Other causes include severe dengue, hantavirus hemorrhagic fever, yellow fever, Lassa fever, Crimean Congo hemorrhagic fever, and Marburg virus.

Viral-Associated Cancers

Nasopharyngeal carcinoma is associated with Epstein-Barr virus (EBV).
Hepatocellular carcinoma is linked to Hepatitis B virus (HBV) and Hepatitis C virus (HCV).
Cervical cancer, anal cancer, and oropharyngeal cancer are associated with Human papillomavirus (HPV), particularly high-risk genotypes.
Vaccines are available for HBV and HPV high-risk genotypes.
Drug treatments exist for HBV and HCV.

Other Medically Important Viruses

Monkeypox is a poxvirus primarily affecting rodents in West/Central Africa.
A large international outbreak occurred in 2022, primarily impacting men who have sex with men (MSM) communities.

Arboviruses

Arboviruses are transmitted by insects
Japanese encephalitis and dengue are two primary arboviruses in Hong Kong.
Other significant arboviruses include Zika virus, West Nile virus, and Yellow Fever virus.
Dengue virus causes a clinical course with viraemia and possible shock, haemorrhage, or dengue fever. Clinical diagnoses include virus isolation, molecular techniques, and the dengue antigen capture ELISA.

Immune System Introduction

Immunity is a defensive mechanism against diseases
Antigens (infectious microbes or large molecules) trigger immune responses.
Pathogens are antigens that break through the immune system.
Different pathogens can be located in the body's cytosol, intracellular locations, or extracellular spaces.

Innate Immunity

Innate immunity is fast, but limited in strength and specificity.
Macrophages and NK cells are part of this type of immunity.

Adaptive Immunity

Adaptive immunity is slower but stronger and specific to antigens, and has memory.
B and T lymphocytes are part of adaptive immunity.

Secondary Immune Response

The secondary immune response has a shorter lag time and higher antibody production.
Strong memory from past exposure or immunization helps in this.
Somatic hypermutation is a key process for generating antibody diversity.

Immune Responses to Infections

Immune responses depend on the type of pathogen (extracellular or intracellular).
Humoral responses involve B cells.
Cell-mediated responses involve T cells.

Humoral Response

Non-specific responses include the complement pathway, interferons, and acute-phase proteins.
Specific responses rely on antibodies from B cells.
Neutralisation, opsonization, and complement-mediated lysis are key functions of antibodies.

Cell-Mediated Immunity

Non-specific responses include phagocytes and natural killer (NK) cells.
Specific responses include cytotoxic T cells (Tc) and helper T cells (TH).
Cytotoxic T cells kill infected cells, while helper T cells help other immune cells function.
Distinct subtypes of TH cells each play different roles in the immune response like TH1, TH2, and TH17.

HIV Infection of CD4+ T Cells

HIV infection depletes CD4+ T cells over time, progressing through stages from seroconversion to symptomatic disease and finally AIDS.

Phagocytes

Phagocytosis involves chemotaxis (directed movement), attachment and uptake of microbes, and destruction by lysosomes.
Macrophages and Granulocytes are two types of phagocytes.

Effector Mechanisms for Phagocytes

Reactive oxygen intermediates (ROIs), reactive nitrogen intermediates (RNIs), and cytokines are employed for microorganism killing.
T-dependent macrophages are activated by T cells. Interferons (e.g., IFN-γ) play a significant role in macrophage activation.

Mucosal Immunity

Mucous is a key first line of defense against pathogens entering through the respiratory tract.
Antigens are picked up by M cells and presented to dendritic cells in lymphoid follicles, leading to IgA-producing plasma cell activation and differentiation
IgA is a critical antibody type in mucosal immunity.

Immunodeficiency

Primary immunodeficiency is typically genetic.
Secondary immunodeficiency is acquired.
Consequences include recurrent infections and opportunistic infections.
Genetic mutations and infections (e.g., HIV) can lead to immunodeficiency.

Anti-Tumor Immunity

Tumor pathogenesis involves genetic mutations, viral-induced mechanisms, and other factors.
Immunosurveillance and immune cells infiltrating tumors provide evidence of anti-tumor immunity.

Immune Checkpoints

Immune checkpoint inhibitors can block PD-1 and PD-L1, allowing T cells to kill tumor cells more effectively.

Innate Immunity Defense Mechanisms

Anatomical barriers prevent entry of pathogens (e.g., skin, mucosa).
Chemical mediators (e.g., lysozyme, defensin) inhibit pathogen growth.
Cellular components (e.g., macrophages, neutrophils) destroy pathogens

Humoral Immune Response

Major components involved include antibodies (immunoglobulins), complement pathway, and interferons.
Antibodies target, neutralise, and activate complement to destroy pathogens.

Cell-Mediated Immunological Response

Involves T-lymphocytes.
Cell-mediated cytotoxicity targets infected cells directly
Cytokines from helper T cells help other immune cells function.

Burnet's Clonal Selection Theory

The theory describes how different antigen-specific immune cells are selected and respond to antigens by proliferating.
Primary and Secondary Responses are distinct phases of the immunological response.

Immunological Memory

Primary and secondary responses differ in time of induction, reaction magnitude, and decline after the reaction phase.
Immunological memory gives a faster and stronger response upon subsequent exposure to the same antigen.

Self and Non-Self Discrimination

The adaptive immunity has unique mechanisms to prevent self-attack.
Central tolerance and peripheral tolerance are important for immune-system self-regulation.

Acute Inflammation

Inflammation is a physiological tissue response to injury caused by ischemia, physical injury, chemical agents, or infections.
The cardinal signs of acute inflammation are redness, swelling, warmth, pain, and loss of function.
Chemical mediators, blood vessels, and neutrophils are involved in the process.

Chronic Inflammation

Prolonged inflammation (weeks or months) with tissue destruction and healing efforts.
Occurs after unresolved acute inflammation or recurring inflammatory triggers.
Histologic characteristics include mononuclear cell infiltrates, tissue destruction, fibrosis, and possible regeneration.
Different chronic inflammatory types exist based on origin (e.g., post-infectious, hypersensitivity).

Antimicrobial Classification

Classification of antimicrobials is based on structure, target mechanism of action, and activity (e.g., bactericidal, bacteriostatic).

Immunization

Artificially inducing immunity to diseases.
Vaccines induce active immunity by including weakened or killed pathogens, and it comes in varying forms (e.g., live-attenuated and inactivated).
Passive immunity involves administration of pre-formed antibodies.

Infection Control

Evidence-based procedures aim to prevent or reduce the risk of microbial transmission in healthcare settings (hospital-acquired infections).

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Description

Test your knowledge on healthcare practices regarding passive immunization, infection control, and hospital-acquired infections. This quiz covers key concepts and potential risks associated with these topics, making it essential for students and professionals in the healthcare field.