Podcast
Questions and Answers
What is the primary mediator of anaphylactic reactions?
What is the primary mediator of anaphylactic reactions?
Which cells are primarily involved in the sensitization phase of anaphylaxis?
Which cells are primarily involved in the sensitization phase of anaphylaxis?
What is the main effect of anaphylactic reactions on non-vascular smooth muscles?
What is the main effect of anaphylactic reactions on non-vascular smooth muscles?
Which of the following is a local manifestation of anaphylaxis?
Which of the following is a local manifestation of anaphylaxis?
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Why do injected antigens often trigger more severe anaphylactic reactions compared to other routes of exposure?
Why do injected antigens often trigger more severe anaphylactic reactions compared to other routes of exposure?
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Which type of hypersensitivity reaction is characterized by immediate onset within 2-30 minutes?
Which type of hypersensitivity reaction is characterized by immediate onset within 2-30 minutes?
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What type of reaction usually involves antigens that are ingested or inhaled?
What type of reaction usually involves antigens that are ingested or inhaled?
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Which type of reaction involves antibodies against cellular or tissue antigens and generally activates complement?
Which type of reaction involves antibodies against cellular or tissue antigens and generally activates complement?
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What is the name for reactions mediated by IgG antibodies 6 to 8 hours after exposure to an antigen?
What is the name for reactions mediated by IgG antibodies 6 to 8 hours after exposure to an antigen?
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Which of the following is an example of a Delayed Type reaction caused by T-cells mainly?
Which of the following is an example of a Delayed Type reaction caused by T-cells mainly?
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What does the term 'Anaphylaxis' mean based on its Greek roots?
What does the term 'Anaphylaxis' mean based on its Greek roots?
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Which of the following is NOT a characteristic of immediate reactions due to Ag-Ab complexes?
Which of the following is NOT a characteristic of immediate reactions due to Ag-Ab complexes?
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Which of the following is NOT a common antibiotic used in dentistry?
Which of the following is NOT a common antibiotic used in dentistry?
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What is the most likely route of exposure to cause sensitization to a drug?
What is the most likely route of exposure to cause sensitization to a drug?
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Which of the following is a characteristic of a rapid-onset allergic reaction to a drug?
Which of the following is a characteristic of a rapid-onset allergic reaction to a drug?
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What is a common skin manifestation of a drug allergy?
What is a common skin manifestation of a drug allergy?
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Which of the following is a characteristic of the sensitization process for a drug allergy?
Which of the following is a characteristic of the sensitization process for a drug allergy?
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What is the most common group of skin manifestations associated with drug allergies?
What is the most common group of skin manifestations associated with drug allergies?
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What percentage of Adverse Drug Reactions (ADRs) are dose-related?
What percentage of Adverse Drug Reactions (ADRs) are dose-related?
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Which type of ADRs do not require a certain dose to elicit a response?
Which type of ADRs do not require a certain dose to elicit a response?
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Which drug is NOT listed as having a high allergenic potential?
Which drug is NOT listed as having a high allergenic potential?
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Which type of anesthetics was commonly used before and had a higher allergic potential?
Which type of anesthetics was commonly used before and had a higher allergic potential?
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What type of reaction occurs generally when the patient is first exposed to a particular drug or agent?
What type of reaction occurs generally when the patient is first exposed to a particular drug or agent?
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Which factor contributes to potentially severe, life-threatening allergic reactions in patients?
Which factor contributes to potentially severe, life-threatening allergic reactions in patients?
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What is the leading cause of anaphylaxis?
What is the leading cause of anaphylaxis?
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Which of the following is NOT one of the four major clinical syndromes of anaphylaxis?
Which of the following is NOT one of the four major clinical syndromes of anaphylaxis?
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Which of the following symptoms indicates a later stage of anaphylaxis?
Which of the following symptoms indicates a later stage of anaphylaxis?
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What is the emergency drug used to treat anaphylaxis?
What is the emergency drug used to treat anaphylaxis?
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Which of the following best describes an idiosyncrasy?
Which of the following best describes an idiosyncrasy?
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What is the most severe consequence of anaphylaxis mentioned in the text?
What is the most severe consequence of anaphylaxis mentioned in the text?
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Study Notes
Immediate Hypersensitivity Reactions
- Mediated by B Lymphocytes, Mast cells, and IgE
- Characterized by sensitization of mast cells and basophils, leading to:
- Capillary dilation and increased capillary permeability (blushing, erythema, edema)
- Release of chemical mediators (histamine, prostaglandins) causing pain, itch, and vasodilation
- Decreased venous return, decreased blood pressure, and decreased cardiac output
- Smooth muscle constriction (bronchospasm) and increased secretion from mucous glands (rhinitis)
Types of Hypersensitivity Reactions
-
Immediate (Type I) Hypersensitivity: IgE-mediated, anaphylactic reactions occurring within 2-30 minutes
- Examples: Generalized anaphylaxis, localized anaphylaxis (urticaria, bronchospasm, food allergy)
-
Cytotoxic (Type II) Hypersensitivity: IgG or IgM-mediated, antibody-dependent cytotoxicity
- Examples: Hemolytic anemia, transfusion reactions
-
Immune Complex (Type III) Hypersensitivity: IgG-mediated, immune complex reactions occurring 6-8 hours after exposure
- Examples: Serum sickness, acute viral hepatitis
-
Delayed (Type IV) Hypersensitivity: Cell-mediated, T-cell mediated reactions occurring 1-2 days after exposure
- Examples: Infectious granulomas (TB), allergic contact dermatitis, chronic hepatitis
Anaphylaxis
- A severe, life-threatening allergic reaction characterized by rapid onset of symptoms
- Can be caused by food, insect stings, drugs, or other substances
- Symptoms include:
- Skin: itching, hives, flushing, angioedema
- Respiratory: coughing, wheezing, dyspnea
- Cardiovascular: tachycardia, hypotension, cardiac arrhythmias
- Gastrointestinal: nausea, vomiting, diarrhea
- Neurological: anxiety, confusion, loss of consciousness
Clinical Manifestations of Allergic Reactions
- Cutaneous manifestations: urticaria, maculopapular rash, erythema, vesicles, ulcers
- Angioedema
- Serum sickness symptoms
- Fixed drug eruption
Anaphylactic Shock and Cardiac Arrest
- Severe, life-threatening complications of anaphylaxis
- Symptoms include:
- Pallor
- Lightheadedness
- Palpitation
- Tachycardia
- Hypotension
- Cardiac arrhythmias
- Cardiac arrest
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Description
Test your knowledge on hyperimmune responses and chemical mediators involved in allergic reactions. Explore the roles of B lymphocytes, mast cells, IgE, and the chemical mediators responsible for symptoms like capillary dilation, increased capillary permeability, pain, itch, bronchospasm, and mucous gland secretion.
