Thrombolysis in Emergency Settings — MCQs
What is the absolute contraindication of oral contraceptive pills (OCPs)?
Absolute contraindication of hormone replacement therapy is:
The clot formed after the coagulation cascade is not stable unless extensive cross-linking occurs. This is done by:
Which of the following drugs is used for treatment of cancer associated thromboembolism?
A 60-year-old man with atrial fibrillation presents with sudden right arm and leg weakness, speech loss, and right facial droop that started 2 hours ago. CT scan shows no bleeding. What is the next step in management?
The treatment of acute myocardial infarction includes which of the following?
Mechanism of action of tranexamic acid is
What is the dose of ulipristal acetate when used for emergency contraception?
Drug of choice for beta antagonist toxicity is?
Which of the following cannula is used in patient with severe dehydration and diarrhea?
Thrombolysis in Emergency Settings Indian Medical PG Practice Questions and MCQs
Question 1: What is the absolute contraindication of oral contraceptive pills (OCPs)?
- A. Dysmenorrhoea
- B. Carcinoma of the breast (Correct Answer)
- C. Endometriosis
- D. Hypertension
Explanation: ***Carcinoma of the breast*** - OCPs contain **estrogen and progesterone**, which can stimulate the growth of **hormone-sensitive breast cancers**. - Therefore, a history of or current **breast cancer** is an absolute contraindication to OCP use. *Dysmenorrhoea* - **Dysmenorrhoea** (painful menstruation) is often effectively treated or alleviated by OCPs due to their ability to suppress ovulation and reduce prostaglandin production. - It is not a contraindication; rather, it is a common indication for OCP use. *Hypertension* - **Uncontrolled severe hypertension** (≥160/100 mmHg) is an absolute contraindication to OCP use. - However, the term "hypertension" alone typically refers to mild or well-controlled hypertension, which is a relative contraindication with careful monitoring. - OCPs can sometimes **increase blood pressure**, requiring careful risk-benefit assessment for individuals with existing hypertension. *Endometriosis* - **Endometriosis** is often managed and its symptoms improved by OCPs, as they help suppress endometrial growth and reduce menstrual flow. - OCPs are a common and effective treatment for endometriosis, not a contraindication.
Question 2: Absolute contraindication of hormone replacement therapy is:
- A. Fibroadenoma
- B. Thrombosis (Correct Answer)
- C. Fibrocystic disease
- D. Hemorrhage
Explanation: ***Thrombosis*** - A history of **thrombosis** (e.g., DVT, pulmonary embolism) is an **absolute contraindication** to hormone replacement therapy (HRT) due to the increased risk of further **thromboembolic events**, as estrogen can promote coagulation [1], [2]. - HRT can increase the risk of **blood clot formation**, making it unsafe for individuals with a prior or current thrombotic condition [1]. *Fibroadenoma* - **Fibroadenomas** are **benign breast lumps** and are generally not considered an absolute contraindication for HRT. - While HRT can potentially cause some **breast density** changes, fibroadenomas do not typically preclude its use, though monitoring may be advised. *Fibrocystic disease* - **Fibrocystic breast disease** is a common **benign breast condition** characterized by lumpy, tender breasts, and it is **not an absolute contraindication** for HRT. - HRT might occasionally exacerbate breast tenderness in some women with fibrocystic changes, but it does not pose a severe health risk. *Hemorrhage* - Acute or uncontrolled **vaginal hemorrhage**, especially of undetermined etiology, is a contraindication to initiating HRT until the cause is identified and managed. - However, once the hemorrhage is controlled and its cause is determined not to be uterine cancer, previous hemorrhage itself is **not an absolute contraindication** to long-term HRT.
Question 3: The clot formed after the coagulation cascade is not stable unless extensive cross-linking occurs. This is done by:
- A. Plasmin
- B. Factor XIII (Correct Answer)
- C. Thrombin
- D. High molecular weight kininogen
Explanation: ***Factor XIII*** - **Factor XIIIa** (activated Factor XIII) is a **transglutaminase** that catalyzes the formation of **covalent bonds** between **fibrin monomers**, specifically between lysine and glutamine residues. - This cross-linking strengthens the **fibrin clot**, making it more resistant to mechanical stress and proteolytic degradation. *Plasmin* - **Plasmin** is an enzyme responsible for **fibrinolysis**, meaning it breaks down fibrin clots. - It acts to remodel and **dissolve clots**, not to stabilize them. *Thrombin* - **Thrombin** (Factor IIa) is a key enzyme in the coagulation cascade that converts **fibrinogen into fibrin monomers**. - While essential for clot formation, thrombin's primary role is to create the fibrin mesh, not to extensively cross-link it for stability. *High molecular weight kininogen* - **High molecular weight kininogen (HMWK)** is a cofactor in the **intrinsic coagulation pathway**, facilitating the activation of Factor XII and prekallikrein. - It is involved in initiating coagulation but does not directly participate in the cross-linking and stabilization of the fibrin clot.
Question 4: Which of the following drugs is used for treatment of cancer associated thromboembolism?
- A. Direct factor Xa inhibitors
- B. Warfarin
- C. Anti-thrombin III inhibitors
- D. LMW heparin (Correct Answer)
Explanation: ***LMW heparin*** - **Low molecular weight heparin (LMWH)** is the **preferred anticoagulant for cancer-associated thrombosis** due to its superior efficacy. - It has a more predictable pharmacokinetic profile compared to unfractionated heparin and is administered subcutaneously. *Direct factor Xa inhibitors* - While effective for general venous thromboembolism (VTE) treatment, some direct oral anticoagulants (DOACs) like factor Xa inhibitors (e.g., rivaroxaban, apixaban) may be considered but have shown mixed results in comparative studies with LMWH for cancer patients, especially those with gastrointestinal cancers, presenting a **higher risk of major bleeding**. - **LMWH** remains the **first-line choice**, especially in patients with active cancer, given the evidence for its greater efficacy and safety profile in this specific population. *Warfarin* - **Warfarin** is generally **not recommended** as a first-line treatment for cancer-associated thromboembolism due to its **drug interactions**, need for frequent monitoring (INR), and slower onset of action. - Patients with cancer often have fluctuating nutritional status, hepatic dysfunction, and receive other medications that can significantly impact warfarin's effectiveness and safety. *Anti-thrombin III inhibitors* - **Antithrombin III inhibitors** (e.g., antithrombin concentrate) are primarily used in specific conditions like **hereditary antithrombin deficiency** or in cases of heparin resistance. - They are **not a standard treatment** for cancer-associated thromboembolism in the general population of cancer patients.
Question 5: A 60-year-old man with atrial fibrillation presents with sudden right arm and leg weakness, speech loss, and right facial droop that started 2 hours ago. CT scan shows no bleeding. What is the next step in management?
- A. Intravenous thrombolysis (Correct Answer)
- B. Surgical thrombectomy
- C. Heparin
- D. Aspirin
Explanation: No change to the explanation was requested other than the addition of citations. ***Intravenous thrombolysis*** - The patient presents with **acute ischemic stroke symptoms** [1] within the 4.5-hour window from symptom onset , and the CT scan shows no hemorrhage , making him a candidate for **tPA**. - **Atrial fibrillation** puts the patient at high risk for cardioembolic stroke , which can be effectively treated with tPA if given early . *Surgical thrombectomy* - This is an intervention for **large vessel occlusion** but is typically considered for patients who are outside the IV tPA window (usually 4.5 hours) or have contraindications, and it often has a longer therapeutic window (up to 24 hours in select cases). - While it may be considered for this patient, **IV thrombolysis** is the immediate next step given he is within the 4.5-hour window and has no contraindications. *Heparin* - **Anticoagulation with unfractionated heparin** is not recommended for acute ischemic stroke without clear indications due to the increased risk of hemorrhagic transformation. - While the patient has atrial fibrillation, starting anticoagulation acutely is usually deferred for at least 24 hours after tPA administration or in cases of larger infarcts due to the risk of bleeding. *Aspirin* - **Aspirin** is an antiplatelet agent used for **secondary stroke prevention** and in some cases for acute ischemic stroke, but it is less effective than tPA for acute reperfusion . - While it may be given later, it is not the primary immediate treatment for acute ischemic stroke eligible for thrombolysis.
Question 6: The treatment of acute myocardial infarction includes which of the following?
- A. Oral anticoagulants
- B. Aspirin (Correct Answer)
- C. Heparin
- D. Alteplase
Explanation: ***Aspirin*** - **Aspirin** is a cornerstone of acute myocardial infarction treatment due to its **antiplatelet effects**, which reduce thrombus formation in the coronary arteries [4]. - It works by **irreversibly inhibiting cyclooxygenase-1 (COX-1)**, thereby preventing the synthesis of thromboxane A2, a potent platelet aggregator [4]. *Heparin* - **Heparin** (unfractionated or low molecular weight) is an **anticoagulant** often used adjunctively in acute MI, particularly in patients undergoing percutaneous coronary intervention (PCI) or with concurrent atrial fibrillation [1]. - Its primary role is to **prevent further clot formation** rather than directly dissolving existing clots, making it not the initial, primary treatment for MI itself. *Alteplase* - **Alteplase** is a **fibrinolytic agent** used in acute ST-elevation myocardial infarction (STEMI) to **dissolve existing clots** and restore blood flow [3]. - While effective, it is not universally indicated for *all* acute MI cases and has specific contraindications, making it a secondary rather than primary initial treatment choice in many scenarios when compared to aspirin [2]. *Oral anticoagulants* - **Oral anticoagulants** (e.g., warfarin, direct oral anticoagulants) are primarily used for **long-term prevention** of thromboembolic events, such as in atrial fibrillation or after venous thromboembolism. - They are generally **not used in the immediate acute phase of MI** as the primary treatment due to their slower onset of action and different mechanisms compared to antiplatelet drugs like aspirin.
Question 7: Mechanism of action of tranexamic acid is
- A. Decrease vascular permeability
- B. Smooth muscle contraction
- C. Activates Plasmin formation
- D. Prevents fibrinolysis (Correct Answer)
Explanation: ***Correct: Prevents fibrinolysis*** - Tranexamic acid is an **antifibrinolytic agent** that works by inhibiting the activation of plasminogen to plasmin. - By preventing the formation of plasmin, it stabilizes **fibrin clots** and reduces bleeding. *Incorrect: Decrease vascular permeability* - This is primarily the mechanism of action of drugs like antihistamines or corticosteroids, which work on **inflammation** and **allergic reactions**. - Tranexamic acid does not directly target vascular permeability; its primary role is in **hemostasis**. *Incorrect: Smooth muscle contraction* - This describes the action of drugs like **vasoconstrictors** (e.g., epinephrine) or agents that promote uterine contractions (e.g., oxytocin). - Tranexamic acid has no direct effect on **smooth muscle contraction**. *Incorrect: Activates Plasmin formation* - This is the opposite of tranexamic acid's action; drugs that activate plasmin, such as **tissue plasminogen activators (tPAs)**, are used to break down clots. - Tranexamic acid specifically **inhibits plasminogen activation**, thereby preventing plasmin formation.
Question 8: What is the dose of ulipristal acetate when used for emergency contraception?
- A. 30mg (Correct Answer)
- B. 300 mg
- C. 300 µg
- D. 30 µg
Explanation: ***30mg*** - The standard dose of **ulipristal acetate** for emergency contraception is a single 30 mg tablet. - This dosage effectively delays or inhibits **ovulation**, making it an effective post-coital contraceptive method. - Ulipristal acetate can be used up to **120 hours (5 days)** after unprotected intercourse, though it is most effective when taken as soon as possible. *300 mg* - A dose of 300 mg of **ulipristal acetate** is significantly higher than the standard therapeutic dose for emergency contraception. - Such a high dose would likely lead to increased side effects and is not recommended for this indication. *300 µg* - A dose of 300 µg (0.3 mg) of **ulipristal acetate** is too low to be effective for emergency contraception. - This dose would not provide sufficient **hormonal inhibition** to prevent ovulation or implantation. *30 µg* - A dose of 30 µg (0.03 mg) of **ulipristal acetate** is also too low for effective emergency contraception. - The efficacy of emergency contraception relies on specific hormonal levels, which this dose would not achieve.
Question 9: Drug of choice for beta antagonist toxicity is?
- A. Adrenaline
- B. Glucagon (Correct Answer)
- C. ACE inhibitors
- D. Dopamine
Explanation: ***Glucagon*** - **Glucagon** is the drug of choice for **beta-blocker overdose** because it bypasses the beta-adrenergic receptors and directly activates **adenylate cyclase** to increase intracellular cAMP [1]. - This action leads to increased heart rate and myocardial contractility, counteracting the cardiac depression caused by beta-blockers [1]. *Adrenaline* - **Adrenaline** (epinephrine) is a beta-agonist, but its effects are blunted in severe **beta-blocker overdose** due to **competitive antagonism** at beta receptors. - While it can be used for its alpha-agonist effects to increase blood pressure, its efficacy in reversing profound bradycardia and myocardial depression may be limited. *ACE inhibitors* - **ACE inhibitors** are used in the management of hypertension and heart failure, primarily by reducing **angiotensin II** formation and inhibiting **bradykinin** degradation. - They have no direct role in reversing the immediate cardiovascular effects of **beta-antagonist toxicity**. *Dopamine* - **Dopamine** is a **catecholamine** with dose-dependent effects, including positive inotropy and chronotropy at higher doses, but it relies on **adrenergic receptor activation**. - Its effects can be attenuated in **beta-blocker overdose**, similar to adrenaline, making it less effective than glucagon as first-line therapy.
Question 10: Which of the following cannula is used in patient with severe dehydration and diarrhea?
- A. Pink
- B. Grey (Correct Answer)
- C. Green
- D. Blue
Explanation: A **16-gauge (Grey)** cannula allows for a high flow rate, making it ideal for rapid fluid resuscitation in severely dehydrated patients [1]. This size is crucial for quickly restoring intravascular volume in cases of severe dehydration and diarrhea where large amounts of fluid are lost. [2] A **20-gauge (Pink)** cannula offers a moderate flow rate, suitable for routine intravenous fluid administration or medication delivery, but generally too slow for rapid resuscitation in severe dehydration. An **18-gauge (Green)** cannula provides a good flow rate, making it suitable for blood transfusions or moderate fluid resuscitation. A **22-gauge (Blue)** cannula has a slow flow rate, typically used for pediatric patients, elderly patients with fragile veins, or for maintaining venous access for medication administration.
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