Anaphylaxis and Allergic Reactions — MCQs
A cardiovascular parameter helpful in diagnosis of anaphylaxis during anaesthesia:
Acute allergic reaction to the penicillin group of drugs is classified as:
Which of the following is false regarding transfusion-associated anaphylactic reactions?
The percutaneous PAIR therapy used in the treatment of uncomplicated hepatic hydatid cyst can be associated with the following complications, except
A child with a known peanut allergy accidentally ingests a food containing peanuts and develops urticaria, vomiting, and wheezing within minutes. What is the first-line treatment?
Carbonic anhydrase inhibitor should not be given in:
Patient following peanut consumption presented with laryngeal edema, stridor, hoarseness of voice and swelling of tongue. Most likely diagnosis is:
A patient undergoing surgery suddenly develops signs of anaphylaxis. What is the best immediate management?
A man takes peanut and develops tongue swelling, neck swelling, stridor, hoarseness of voice. What is the probable diagnosis?
A drug used to prevent niacin-induced flushing is
Anaphylaxis and Allergic Reactions Indian Medical PG Practice Questions and MCQs
Question 1: A cardiovascular parameter helpful in diagnosis of anaphylaxis during anaesthesia:
- A. Bradycardia
- B. Dysrhythmia
- C. Increased peripheral vascular resistance
- D. Hypotension (Correct Answer)
Explanation: ***Hypotension*** - **Hypotension** is a hallmark cardiovascular sign of anaphylaxis, occurring due to widespread **vasodilation** and increased vascular permeability. - This symptom is often profound and unresponsive to initial fluid resuscitation due to the ongoing systemic release of inflammatory mediators. *Bradycardia* - While bradycardia can occur in some rare cases of anaphylaxis (e.g., **vasovagal response**), **tachycardia** is the more common cardiac response due to compensatory mechanisms. - It is not a primary or consistent indicator of anaphylaxis, making it less helpful for diagnosis in this context. *Dysrhythmia* - **Dysrhythmias** can occur during anaphylaxis due to myocardial ischemia or electrolyte imbalances, but they are not a direct or consistent diagnostic feature. - Their presence often reflects severe compromise or co-existing conditions rather than being a primary anaphylactic sign. *Increased peripheral vascular resistance* - Anaphylaxis is characterized by a significant **decrease in peripheral vascular resistance** due to mast cell and basophil degranulation releasing vasodilatory mediators like histamine. - Therefore, an increase in peripheral vascular resistance would contradict the pathophysiology of anaphylaxis.
Question 2: Acute allergic reaction to the penicillin group of drugs is classified as:
- A. Type 1 reaction (Correct Answer)
- B. Type 2 reaction
- C. Type 3 reaction
- D. Type 4 reaction
Explanation: ***Type 1 reaction*** - Penicillin allergy is a classic example of a **Type I hypersensitivity reaction**, mediated by **IgE antibodies**. - Symptoms like **anaphylaxis**, **urticaria**, and **angioedema** develop rapidly upon re-exposure to the drug. *Type 2 reaction* - **Type II hypersensitivity reactions** involve **IgG** or **IgM antibodies** binding to antigens on cell surfaces, leading to cell destruction. - Examples include **hemolytic anemia** due to drug-induced antibodies, which is not the primary mechanism of typical penicillin allergy. *Type 3 reaction* - **Type III hypersensitivity reactions** involve the formation of **immune complexes** (antigen-antibody complexes) that deposit in tissues. - This can lead to conditions like **serum sickness** or **vasculitis**, which are less common manifestations of penicillin allergy. *Type 4 reaction* - **Type IV hypersensitivity reactions** are **delayed-type hypersensitivity (DTH)** reactions, mediated by **T cells** rather than antibodies. - These reactions typically manifest 24-72 hours after exposure, as seen in **contact dermatitis**; while some penicillin reactions can be T-cell mediated, the acute, life-threatening allergic response is Type I.
Question 3: Which of the following is false regarding transfusion-associated anaphylactic reactions?
- A. Different from allergy
- B. Epinephrine is the drug of choice
- C. Washed blood products prevent it
- D. Seen in IgG deficient individuals (Correct Answer)
Explanation: ***Seen in IgG deficient individuals*** - Transfusion-associated **anaphylactic reactions** are most commonly seen in **IgA-deficient individuals** who develop **anti-IgA antibodies** and receive blood products containing IgA. - Anaphylaxis occurs when these pre-formed IgA antibodies react with donor IgA, leading to mast cell degranulation and severe allergic symptoms. *Different from allergy* - Transfusion-associated **anaphylactic reactions** are a severe form of allergic reaction, often distinguished by their **rapid onset** and life-threatening nature [1]. - While all allergies involve an immune response to an allergen, anaphylaxis represents the most extreme systemic manifestation. *Epinephrine is the drug of choice* - **Epinephrine** is indeed the **first-line treatment** for acute anaphylaxis, regardless of its cause, including transfusion-associated reactions [2]. - It acts rapidly to counteract the systemic effects of histamine and other mediators by acting on α and β adrenergic receptors [3]. *Washed blood products prevent it* - **Washing blood products** (e.g., packed red blood cells or platelets) is an effective strategy to **remove plasma proteins**, including IgA. - This is particularly crucial for patients with a known **IgA deficiency and anti-IgA antibodies** to prevent severe anaphylactic reactions.
Question 4: The percutaneous PAIR therapy used in the treatment of uncomplicated hepatic hydatid cyst can be associated with the following complications, except
- A. hypotension
- B. bradycardia (Correct Answer)
- C. vomiting
- D. anaphylaxis
Explanation: ***bradycardia*** - **Bradycardia is not a recognized primary complication** of percutaneous aspiration, injection, and re-aspiration (PAIR) therapy for hydatid cysts. - While bradycardia can occur as a **vasovagal response during any invasive procedure**, it is not specifically listed among the complications of PAIR therapy in standard medical literature. - The typical cardiovascular manifestation of anaphylaxis (a known PAIR complication) is **tachycardia**, not bradycardia. *hypotension* - **Hypotension** is a well-documented complication of PAIR therapy, occurring due to **anaphylactic reaction** from leakage of antigenic hydatid fluid into the circulation. - It can also result from **intra-abdominal hemorrhage** if a major vessel is inadvertently punctured during the procedure. *vomiting* - **Vomiting** can occur as part of a **systemic allergic reaction or anaphylaxis** triggered by the release of hydatid cyst contents. - It may also be a manifestation of peritoneal irritation if cyst contents leak into the peritoneal cavity. *anaphylaxis* - **Anaphylaxis** is the most feared and well-documented complication of PAIR therapy, caused by the release of **highly antigenic hydatid cyst fluid** (containing protoscolices and hydatid antigens) into the host's system. - This severe Type I hypersensitivity reaction can manifest with **hypotension, tachycardia, bronchospasm, urticaria, angioedema**, and in severe cases, cardiovascular collapse. - Prophylactic antihistamines and corticosteroids are often administered to minimize this risk.
Question 5: A child with a known peanut allergy accidentally ingests a food containing peanuts and develops urticaria, vomiting, and wheezing within minutes. What is the first-line treatment?
- A. Oral antihistamines
- B. Subcutaneous epinephrine
- C. Intramuscular epinephrine (Correct Answer)
- D. High-dose corticosteroids
Explanation: ***Intramuscular epinephrine*** - This patient is experiencing **anaphylaxis**, characterized by rapid-onset **urticaria**, **vomiting** (gastrointestinal involvement), and **wheezing** (respiratory involvement). - **Epinephrine** is the **first-line treatment** for anaphylaxis due to its alpha-1 agonist effects (vasoconstriction to counteract hypotension and reduce angioedema) and beta-2 agonist effects (bronchodilation to relieve wheezing). Intramuscular administration ensures rapid absorption and systemic effect. *Oral antihistamines* - While antihistamines can help manage cutaneous symptoms like **urticaria** and **itching**, they do not address the life-threatening respiratory or cardiovascular symptoms of anaphylaxis. - They are considered **adjunctive therapy** for mild allergic reactions but are not sufficient as first-line treatment for anaphylaxis. *Subcutaneous epinephrine* - **Subcutaneous administration** is historical and **not recommended** for anaphylaxis because it has a slower and less predictable absorption compared to intramuscular injection. - The delay in onset of action can be critical in a rapidly progressing anaphylactic reaction. *High-dose corticosteroids* - **Corticosteroids** act too slowly to be useful as a primary treatment for acute anaphylaxis, as their effects take several hours to manifest. - They are used as **adjunctive therapy** to prevent protracted or biphasic reactions, but not for the initial management of acute symptoms.
Question 6: Carbonic anhydrase inhibitor should not be given in:
- A. Epilepsy
- B. High altitude sickness
- C. Sulfonamide hypersensitivity (Correct Answer)
- D. Glaucoma
Explanation: ***Sulfonamide hypersensitivity*** - Carbonic anhydrase inhibitors (CAIs) are **sulfonamide derivatives**, so they are absolutely contraindicated in patients with a history of **sulfonamide allergy**. - Administration to such patients can lead to severe **hypersensitivity reactions**, including rash, fever, and even anaphylaxis. *Epilepsy* - **Acetazolamide**, a carbonic anhydrase inhibitor, can be used as an **adjunct therapy for certain types of epilepsy**, such as absence seizures. - It works by reducing neuronal excitability through its effects on pH, thus it is not contraindicated but rather sometimes indicated. *High altitude sickness* - Carbonic anhydrase inhibitors like **acetazolamide** are commonly used to **prevent and treat high altitude cerebral and pulmonary edema** by inducing metabolic acidosis and stimulating respiration. - This is a recognized therapeutic indication, not a contraindication. *Glaucoma* - CAIs are a **primary treatment for glaucoma** (both open-angle and angle-closure) because they reduce the production of aqueous humor, thereby lowering intraocular pressure. - They are used both systemically and topically for this purpose, making it an indication, not a contraindication.
Question 7: Patient following peanut consumption presented with laryngeal edema, stridor, hoarseness of voice and swelling of tongue. Most likely diagnosis is:
- A. Foreign body bronchus
- B. Angioneurotic edema (Correct Answer)
- C. Foreign body larynx
- D. Pharyngeal abscess
Explanation: ***Angioneurotic edema*** - The rapid onset of **laryngeal edema**, **stridor**, **hoarseness**, and **tongue swelling** following peanut consumption points to an allergic reaction, specifically **anaphylaxis** causing angioedema [1], [2]. - This is a life-threatening condition due to potential **airway obstruction**. *Foreign body bronchus* - While a foreign body could cause **stridor** if large enough to impact the trachea, symptoms like **laryngeal edema** and **tongue swelling** are not typical. - It usually presents with sudden coughing, wheezing, and possibly dyspnea, often without rapid-onset, diffuse swelling. *Foreign body larynx* - A foreign body in the larynx might cause hoarseness and stridor, but **laryngeal edema** and **tongue swelling** are not primary features of a simple foreign body obstruction. - The history of peanut ingestion and rapid systemic inflammatory response makes an allergic reaction more likely [2]. *Pharyngeal abscess* - A pharyngeal abscess typically develops more slowly, with symptoms including **severe sore throat**, **fever**, and **difficulty swallowing**. - It would not usually present with the rapid onset of severe **laryngeal edema** and **tongue swelling** immediately after peanut consumption.
Question 8: A patient undergoing surgery suddenly develops signs of anaphylaxis. What is the best immediate management?
- A. Give atropine
- B. Increase level of anesthesia
- C. Ask the surgeon to stop the surgery
- D. Give adrenaline (Correct Answer)
Explanation: ***Give adrenaline*** - **Adrenaline (epinephrine)** is the first-line treatment for anaphylaxis due to its alpha-1 adrenergic effects (vasoconstriction, increasing blood pressure) and beta-2 adrenergic effects (bronchodilation). - Its rapid administration is crucial to counteract systemic vasodilation, bronchospasm, and cardiovascular collapse characteristic of anaphylaxis. *Give atropine* - **Atropine** is an anticholinergic drug primarily used to treat **bradycardia**; it does not address the widespread vasodilation, bronchoconstriction, or histamine release seen in anaphylaxis. - Giving atropine would not treat the underlying pathological mechanisms of an anaphylactic reaction. *Increase level of anesthesia* - Increasing the level of anesthesia might mask some symptoms but would not treat the underlying **hypotension**, **bronchospasm**, or other systemic effects of anaphylaxis. - Anaphylaxis requires specific pharmacological intervention, not simply deeper sedation. *Ask the surgeon to stop the surgery* - While stopping the surgery might be a necessary step in severe cases to facilitate patient management, it is not the immediate **pharmacological intervention** required to treat the life-threatening symptoms of anaphylaxis. - The immediate priority is to stabilize the patient's condition with appropriate medication.
Question 9: A man takes peanut and develops tongue swelling, neck swelling, stridor, hoarseness of voice. What is the probable diagnosis?
- A. FB in larynx
- B. Angioneurotic edema (Correct Answer)
- C. Parapharyngeal abscess
- D. FB bronchus
Explanation: Andioneurotic edema - The combination of **tongue swelling**, **neck swelling**, **stridor**, and **hoarseness of voice** following peanut ingestion is highly suggestive of **angioneurotic edema**, a severe allergic reaction that can lead to airway obstruction [1]. - This is a life-threatening condition requiring immediate medical intervention, often associated with generalized **anaphylaxis** when triggered by allergens [2]. *FB in larynx* - While a **foreign body (FB) in the larynx** can cause stridor and hoarseness, the widespread swelling of the tongue and neck points away from a localized laryngeal obstruction [3]. - A laryngeal FB would typically be associated with a more sudden onset of choking and coughing, not diffuse edema [3]. *Parapharyngeal abscess* - A **parapharyngeal abscess** would typically present with **fever**, **severe throat pain**, and **trismus** (difficulty opening the mouth), which are not mentioned in this scenario. - The acute, rapid onset of symptoms after peanut consumption is inconsistent with the slower progression of an abscess. *FB bronchus* - A **foreign body in the bronchus** would primarily cause **coughing**, **wheezing**, and possibly **respiratory distress**, often unilateral, rather than severe global swelling of the tongue and neck. - Inspiratory stridor and hoarseness are more indicative of upper airway involvement than bronchial obstruction.
Question 10: A drug used to prevent niacin-induced flushing is
- A. Dexamethasone
- B. Aspirin (Correct Answer)
- C. Paracetamol
- D. Cetirizine
Explanation: ***Aspirin*** - Niacin-induced flushing is mediated by **prostaglandins**, primarily prostaglandin D2 (PGD2), which cause vasodilation. - **Aspirin**, being a non-steroidal anti-inflammatory drug (NSAID) and a cyclooxygenase (COX) inhibitor, blocks the synthesis of prostaglandins, thereby reducing flushing. *Cetirizine* - Cetirizine is a **second-generation H1 antihistamine** primarily used to treat allergic symptoms like rhinitis or urticaria. - It does not significantly affect prostaglandin pathways implicated in niacin-induced flushing. *Dexamethasone* - Dexamethasone is a **corticosteroid** with potent anti-inflammatory and immunosuppressive effects. - While it can broadly reduce inflammation, it is not the primary or most appropriate treatment for niacin-induced flushing, which is better managed with prostaglandin inhibitors. *Paracetamol* - Paracetamol (acetaminophen) is an **analgesic and antipyretic** that works primarily by inhibiting prostaglandin synthesis in the central nervous system. - It has minimal anti-inflammatory effects and does not effectively reduce peripheral prostaglandin production responsible for niacin flush.
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