Electrosurgery — MCQs
The main danger with low tension alternating current is
Which distension medium is used for hysteroscopy with bipolar cautery?
High tension electrical burns from overhead electrical lines can cause:
What is a contraindication for ECT?
Indications for ECT are all except?
A 40 year old man presented with a flat 1x1cm scaly, itchy black mole on the front of thigh. Examination did not reveal any inguinal lymphodenopathy. The best course of management would be:
Unna boot is used for the treatment of which condition?
Which of the following is NOT true regarding patch testing?
A 45-year-old farmer presents with a 3-year history of itchy, erythematous papular lesions on the face, neck, 'V' area of the chest, and the dorsum of the hands and forearms. The lesions are more severe in the summer and improve significantly in the winter. What is the most appropriate diagnostic test for this condition?
Patch test is done to document which type of hypersensitivity?
Electrosurgery Indian Medical PG Practice Questions and MCQs
Question 1: The main danger with low tension alternating current is
- A. Cardiac arrest (Correct Answer)
- B. Renal failure
- C. Myoglobinuria
- D. Burns
Explanation: ***Cardiac arrest*** - Low-tension alternating current (AC) is particularly dangerous because it can induce **ventricular fibrillation** at relatively low current levels. - The alternating nature allows for sustained muscle contraction and higher likelihood of interfering with the heart's electrical rhythm, leading to **cardiac arrest**. *Renal failure* - While severe electrical injuries can cause **rhabdomyolysis** and subsequent acute renal failure, this is typically associated with higher voltage and extensive tissue damage, not the primary danger of low-tension AC. - The immediate and most frequent life-threatening consequence of low-tension AC is its effect on the **heart rhythm**. *Myoglobinuria* - **Myoglobinuria** results from severe muscle damage (rhabdomyolysis), which can occur with electrical injury. - This is a consequence of significant tissue destruction, which is less common with low-tension AC compared to the risk of **cardiac arrhythmias**. *Burns* - **Burns** are a common consequence of electrical shock, especially with high-tension currents or prolonged contact. - While low-tension AC can cause burns, particularly at the contact points, the most immediate life-threatening risk is the disruption of **cardiac electrical activity**.
Question 2: Which distension medium is used for hysteroscopy with bipolar cautery?
- A. NS (Correct Answer)
- B. Glycine
- C. Carbon Dioxide
- D. Dextran 70
Explanation: ***NS*** - **Normal Saline (NS)** is an **electrolyte-containing solution** (0.9% NaCl) and is thus safe to use with **bipolar electrosurgery** because it does not conduct current across the tissue but only between the two poles of the instrument. - Its isotonicity minimizes fluid shifts and its clear nature allows for good visualization. *Glycine* - **Glycine** is a **non-electrolyte solution** that is used with **monopolar electrosurgery**, as it does not conduct electrical current to the patient but only through the active electrode. - Using it with bipolar devices is unnecessary and can lead to complications such as **dilutional hyponatremia** and **hyperammonemia** if significant intravascular absorption occurs. *Carbon Dioxide* - **Carbon dioxide** is used as a distension medium for **diagnostic hysteroscopy** because of its lack of risk for fluid overload and clear visualization. - It is **contraindicated with electrosurgery** because of the risk of **gas embolism** and its potential for impaired visualization with significant bleeding. *Dextran 70* - **Dextran 70** is a **high-viscosity, non-electrolyte solution** primarily used for diagnostic hysteroscopy when blood or mucus obscures the view. - It is **contraindicated for electrosurgery** due to its non-conductive nature and the risk of **anaphylactic reactions** and **pulmonary edema** from volume expansion.
Question 3: High tension electrical burns from overhead electrical lines can cause:
- A. Myoglobinuria and Acute renal failure (Correct Answer)
- B. No ECG change will be seen in the first 24 hrs
- C. Severe alkalosis
- D. Blood vessels are spared
Explanation: ***Myoglobinurea and Acute renal failure*** - High tension electrical burns cause extensive **muscle damage** (rhabdomyolysis), leading to the release of **myoglobin** into the bloodstream. - **Myoglobinuria** can precipitate in the renal tubules, leading to **acute tubular necrosis** and subsequent **acute renal failure**. *No ECG change will be seen in the first 24 hrs* - Electrical burns often cause significant **cardiac irritation** and **arrhythmias**, which are typically identifiable on an **ECG** within the first 24 hours. - Damage to the heart due to the direct passage of current can result in various ECG changes, including **QT interval prolongation**, **ST segment changes**, and **tachyarrhythmias** or **bradyarrhythmias**. *Severe alkalosis* - Patients with significant electrical burns are more likely to develop **metabolic acidosis** due to tissue hypoperfusion, massive **cell death**, and the accumulation of **lactic acid**. - **Alkalosis** is not a typical presentation or complication of high tension electrical burns. *Blood vessels are spared* - Blood vessels, especially those with smaller diameters, are particularly susceptible to **thermal damage** from electrical current, leading to **coagulation** and **thrombosis**. - This vascular damage can result in **ischemia** and **necrosis** in affected tissues, often requiring significant debridement and reconstruction.
Question 4: What is a contraindication for ECT?
- A. Epilepsy
- B. HIV
- C. Cerebral aneurysm (Correct Answer)
- D. Arrhythmia
Explanation: ***Cerebral aneurysm*** * A **cerebral aneurysm** is considered a **relative contraindication** for electroconvulsive therapy (ECT) due to the increased risk of rupture from the transient, but significant, rise in **blood pressure** and **intracranial pressure** during the procedure. * The cardiovascular stress induced by the seizure can worsen pre-existing vascular pathologies in the brain, making it a high-risk condition. *Arrhythmia* * While various cardiac conditions require careful monitoring during ECT, **arrhythmias** are generally not an absolute contraindication. * Patients can often undergo ECT with proper **cardiac monitoring** and **pharmacological management** to control the heart rhythm during the procedure. *Epilepsy* * **Epilepsy** is not a contraindication for ECT; in fact, ECT *artificially induces a seizure* to achieve therapeutic effects. * The presence of epilepsy primarily impacts the choice of **anticonvulsant medications** and the need for potentially higher seizure thresholds, but it does not preclude ECT. *HIV* * **HIV infection** itself is not a contraindication for ECT. * ECT can be safely administered to HIV-positive individuals, with consideration given to the patient's overall **physical health**, **medication interactions**, and any co-morbid opportunistic infections.
Question 5: Indications for ECT are all except?
- A. Severe psychosis
- B. Catatonic schizophrenia
- C. Severe manic attack (Correct Answer)
- D. Severe depression with suicidal risk
Explanation: ***Severe manic attack*** - While **severe mania IS a recognized indication for ECT**, it is generally considered **less commonly used as first-line therapy** compared to the other options listed. - In clinical practice, **acute severe mania** is typically managed initially with **antipsychotics and mood stabilizers** (lithium, valproate), with ECT reserved for **treatment-resistant cases** or when rapid response is critical. - ECT is highly effective for severe mania, particularly with **psychotic features** or **medication intolerance**, but is not the **most typical first-choice indication** compared to severe depression or catatonia. - This question reflects the **relative clinical priority** of ECT indications rather than absolute contraindication. *Severe depression with suicidal risk* - This is the **most common and well-established indication for ECT**. - ECT provides **rapid antidepressant effect** (often within 1-2 weeks) and is particularly indicated when there is **imminent suicide risk**, **psychotic depression**, or **treatment-resistant depression**. - Response rates exceed 70-90% in severe depression, making it a primary indication. *Catatonic schizophrenia* - **Catatonia is one of the strongest indications for ECT**, regardless of underlying etiology (schizophrenia, mood disorders, or medical conditions). - ECT rapidly resolves **catatonic symptoms** including mutism, stupor, posturing, and waxy flexibility. - Often considered **first-line treatment** for severe or malignant catatonia due to life-threatening complications. *Severe psychosis* - ECT is indicated for **severe psychotic disorders** that are **treatment-resistant** or when patients cannot tolerate antipsychotic medications. - Particularly effective in **acute psychotic agitation**, **treatment-refractory schizophrenia**, and psychosis with high risk of harm. - Provides rapid symptom control when pharmacotherapy has failed or is contraindicated.
Question 6: A 40 year old man presented with a flat 1x1cm scaly, itchy black mole on the front of thigh. Examination did not reveal any inguinal lymphodenopathy. The best course of management would be:
- A. FNAC of lesion
- B. Incision biopsy
- C. Wide excision with inguinal lymphadenectomy
- D. Excision biopsy (Correct Answer)
Explanation: ***Excision biopsy*** - A **flat, scaly, itchy, black mole** is highly suspicious for **melanoma**, and an excision biopsy provides the most accurate histopathological diagnosis and depth assessment. - This procedure removes the entire lesion with a narrow margin of normal-appearing skin, allowing for comprehensive evaluation of its nature and determining further management. *FNAC of lesion* - **Fine needle aspiration cytology (FNAC)** is generally used for evaluating palpable masses or lymph nodes, not primary skin lesions like a suspicious mole. - It provides only cellular samples, making it difficult to assess architectural features, depth of invasion, or determine definitive malignancy in skin lesions. *Incision biopsy* - An **incision biopsy** involves removing only a partial sample of the lesion, which can lead to sampling error and an inaccurate diagnosis if the most aggressive part is missed. - For suspected melanoma, an incomplete biopsy can compromise subsequent staging and definitive treatment planning. *Wide excision with inguinal lymphadenectomy* - This is an **overly aggressive initial approach** before a definitive diagnosis of melanoma and its stage has been established. - **Wide excision** is typically performed after an excision biopsy confirms melanoma and determines its depth, while **lymphadenectomy** is indicated for confirmed lymph node involvement.
Question 7: Unna boot is used for the treatment of which condition?
- A. Diabetic foot ulcer
- B. Varicose ulcers (Correct Answer)
- C. Ankle instability
- D. Calcaneum fracture
Explanation: **Explanation:** The **Unna boot** is a specialized compression dressing used primarily for the management of **venous stasis ulcers (varicose ulcers)**. It consists of a zinc oxide-impregnated bandage, often containing calamine and glycerin, which is wrapped around the lower leg from the base of the toes to just below the knee. **Why it is the correct answer:** The mechanism of action is based on **compression therapy**. As the bandage dries, it becomes semi-rigid. When the patient walks, the calf muscles contract against this rigid barrier, significantly enhancing the **musculovenous pump** efficiency. This reduces venous hypertension, decreases edema, and promotes the healing of chronic venous ulcers. **Analysis of Incorrect Options:** * **Diabetic foot ulcer:** These are primarily neuropathic or ischemic. Treatment focuses on offloading pressure (e.g., total contact casts) and revascularization, rather than the semi-rigid compression provided by an Unna boot. * **Ankle instability:** This requires mechanical stabilization via braces, taping, or surgical intervention to protect ligaments, not a medicated compression wrap. * **Calcaneum fracture:** Fractures require rigid immobilization (plaster casts) or surgical fixation. An Unna boot does not provide sufficient structural support for bone healing. **High-Yield Clinical Pearls for NEET-PG:** * **Composition:** Zinc oxide (promotes healing), Calamine (soothes skin), and Glycerin. * **Contraindication:** It should **not** be used in patients with severe Peripheral Arterial Disease (ABI < 0.5) as compression can worsen ischemia. * **Application:** It is typically changed once a week. * **Gold Standard:** While Unna boots are classic, multilayer compression wraps are now often considered the gold standard for venous ulcers.
Question 8: Which of the following is NOT true regarding patch testing?
- A. Used to diagnose allergic contact dermatitis
- B. Readings are typically taken after 48 hours
- C. False negative results can occur in patients with angry back syndrome (Correct Answer)
- D. The T.R.U.E. test is a type of patch test
Explanation: **Explanation:** **1. Why Option C is the correct answer (The False Statement):** **Angry Back Syndrome** (also known as **Excited Skin Syndrome**) refers to a state of skin hyper-reactivity where a strong positive reaction at one patch test site triggers non-specific positive reactions at other sites. Therefore, it leads to **false-positive** results, not false-negative results. This occurs because the skin's threshold for irritation is lowered globally due to a localized severe inflammatory response. **2. Analysis of Incorrect Options (True Statements):** * **Option A:** Patch testing is the **gold standard** for diagnosing Type IV (delayed-type) hypersensitivity reactions, specifically **Allergic Contact Dermatitis (ACD)**. * **Option B:** In a standard protocol, patches are applied for **48 hours**, removed, and the first reading is taken. a second reading is typically taken at **72–96 hours** to identify delayed reactions. * **Option D:** The **T.R.U.E. test** (Thin-layer Rapid Use Epicutaneous test) is a widely used, standardized, ready-to-use patch testing system containing common allergens impregnated into polyester patches. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Type IV Hypersensitivity (Cell-mediated). * **Prick Test vs. Patch Test:** Prick tests are for Type I (IgE-mediated) reactions (e.g., asthma, urticaria), while Patch tests are for Type IV. * **Grading (ICDRG):** * **+:** Weak (non-vesicular) reaction (erythema, infiltration). * **++:** Strong (vesicular) reaction. * **+++:** Extreme (bullous) reaction. * **IR:** Irritant reaction (usually sharply demarcated, "burned" appearance). * **Contraindication:** Testing should not be done during an acute flare-up of dermatitis or if the patient is on high-dose systemic corticosteroids (usually >15-20mg prednisolone).
Question 9: A 45-year-old farmer presents with a 3-year history of itchy, erythematous papular lesions on the face, neck, 'V' area of the chest, and the dorsum of the hands and forearms. The lesions are more severe in the summer and improve significantly in the winter. What is the most appropriate diagnostic test for this condition?
- A. Patch test (Correct Answer)
- B. Skin biopsy
- C. Intradermal prick test
- D. Estimation of IgE levels in blood
Explanation: ### Explanation **Diagnosis: Parthenium Dermatitis (Airborne Contact Dermatitis)** The clinical presentation of itchy, erythematous papules in a "photo-distributed" pattern (face, neck, 'V' area of chest, and dorsum of hands/forearms) in a farmer, with seasonal exacerbation in summer, is classic for **Parthenium Dermatitis**. This is a type of **Airborne Contact Dermatitis (ABCD)** caused by the weed *Parthenium hysterophorus*. **1. Why Patch Test is the Correct Answer:** Parthenium dermatitis is a **Type IV (Delayed-type) Hypersensitivity reaction**. The gold standard for diagnosing Type IV hypersensitivity is the **Patch Test**. It identifies the specific allergen (usually the sesquiterpene lactone in Parthenium) responsible for the T-cell mediated allergic response. **2. Why Other Options are Incorrect:** * **Skin Biopsy:** While it may show features of eczematous dermatitis (spongiosis), it is non-specific and cannot identify the causative allergen. * **Intradermal Prick Test:** This is used to diagnose **Type I (Immediate) Hypersensitivity** (e.g., asthma, allergic rhinitis). It is not used for contact dermatitis. * **Estimation of IgE levels:** IgE is a marker for Type I hypersensitivity and atopic conditions. It has no diagnostic value in Type IV hypersensitivity reactions like ABCD. **Clinical Pearls for NEET-PG:** * **Distribution:** Unlike true photodermatitis, ABCD often involves the **upper eyelids, nasolabial folds, and retroauricular areas** (the "shadow regions"), as pollen/dust can settle there. * **Common Allergen:** In India, *Parthenium hysterophorus* (Congress grass) is the most common cause. * **Management:** Avoidance of the allergen is key. Topical steroids and sun protection are used for symptomatic relief. In chronic cases, azathioprine may be used as a steroid-sparing agent.
Question 10: Patch test is done to document which type of hypersensitivity?
- A. Type I hypersensitivity
- B. Delayed type hypersensitivity (Correct Answer)
- C. Autoimmune disease
- D. Immunocomplex deposition
Explanation: ### Explanation **Correct Answer: B. Delayed type hypersensitivity** The **Patch Test** is the gold standard diagnostic tool for **Allergic Contact Dermatitis (ACD)**. ACD is a classic example of **Type IV Hypersensitivity** (also known as Delayed-type Hypersensitivity). * **Mechanism:** This reaction is **T-cell mediated** (specifically Th1 cells) rather than antibody-mediated. When an allergen contacts the skin of a sensitized individual, memory T-cells recognize the antigen, leading to the release of cytokines and subsequent inflammation. * **Timing:** Because it takes time for T-cell recruitment and cytokine production, the reaction typically peaks at **48 to 72 hours**, which is why patch test readings are performed at these intervals. --- ### Why other options are incorrect: * **A. Type I Hypersensitivity:** This is an immediate, IgE-mediated reaction (e.g., Anaphylaxis, Urticaria). It is tested using the **Skin Prick Test**, not the Patch Test. * **C. Autoimmune Disease:** While some autoimmune skin diseases (like Pemphigus) are diagnosed via Immunofluorescence (DIF/IIF), the patch test specifically identifies external allergens, not auto-antibodies against self-antigens. * **D. Immunocomplex Deposition:** This refers to **Type III Hypersensitivity** (e.g., SLE, Vasculitis). These are typically diagnosed via skin biopsy and direct immunofluorescence showing granular deposits (e.g., Lumpy-bumpy pattern). --- ### High-Yield Facts for NEET-PG: * **Standard Series:** The most commonly used series globally is the **European Standard Series**; in India, it is the **ISDR (Indian Standard Series)**. * **Commonest Allergen:** Globally, **Nickel** (found in artificial jewelry) is the most common allergen. In India, **Parthenium** (Congress grass) is a frequent cause of airborne contact dermatitis. * **Reading Schedule:** Readings are usually taken at **48 hours** (removal of patches) and **72 or 96 hours** (delayed reading). * **Open Patch Test:** Used for substances with potential irritancy or volatile compounds.
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