Cryotherapy — MCQs
Incorrect statement regarding the management of frostbite:
Most important disadvantage of cryosurgery for hemorrhoids is:
All are true about erythema multiforme except which of the following?
Identify the lesion: (Recent NEET Pattern 2016-17)
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?
A 19-year-old man develops a rash in the groin area. On examination, it is a large well-demarcated area of tan-brown discoloration around his left inguinal area. There is some scaling of the lesion when brushed with a tongue depressor. Which of the following is the most appropriate initial diagnostic test?
What is the best method to treat large port-wine hemangiomas?
Cryotherapy Indian Medical PG Practice Questions and MCQs
Question 1: Incorrect statement regarding the management of frostbite:
- A. Antibiotics and analgesics not used (Correct Answer)
- B. Amputation in severe cases
- C. Rewarming is done
- D. The area is dried and cleaned
Explanation: ***Antibiotics and analgesics not used*** - This statement is incorrect as **antibiotics are used** in the management of frostbite for prophylaxis against infection, especially in severe cases or open wounds. - **Analgesics are also crucial** to manage the significant pain associated with frostbite and the rewarming process [1]. *Amputation in severe cases* - **Amputation** is a necessary intervention for severe, irreversible tissue damage and necrosis caused by frostbite, typically reserved as a last resort [1]. - This decision is usually made after sufficient time has passed to demarcate viable from non-viable tissue, often several weeks post-injury [1]. *Rewarming is done* - **Rapid rewarming** of the affected area in a warm water bath (37-39°C) is the most critical initial treatment for frostbite to minimize tissue damage. - This process is painful and should be done only when there is no risk of refreezing. *The area is dried and cleaned* - After rewarming, the affected area should be **gently dried** to prevent further skin breakdown and the development of maceration. - **Cleaning the wound** helps prevent infection and maintains a sterile environment for healing.
Question 2: Most important disadvantage of cryosurgery for hemorrhoids is:
- A. Pain
- B. Infection
- C. Profuse watery discharge (Correct Answer)
- D. Hemorrhage
Explanation: ***Profuse watery discharge*** - **Profuse, foul-smelling watery discharge** is the **most important and troublesome disadvantage** of cryosurgery for hemorrhoids. - Results from **tissue necrosis and sloughing** following freezing, lasting **2-3 weeks** post-procedure. - This persistent discharge is **socially distressing**, requires frequent dressing changes, and is the primary reason cryosurgery has **largely fallen out of favor** in modern practice. - The severity and duration of this complication makes it more problematic than other side effects. *Pain* - While postoperative discomfort does occur, pain after cryosurgery is **generally not more severe** than with other hemorrhoid procedures. - The freezing effect can actually cause **temporary nerve damage** that may reduce immediate pain sensation. - Pain is manageable with standard analgesics and is **not the defining disadvantage** of this technique. *Infection* - Infection is **uncommon** with cryosurgery as the ultra-cold temperatures have some **antibacterial effect**. - Not a characteristic or major complication of this specific technique. *Hemorrhage* - Cryosurgery actually has a **lower risk of immediate bleeding** compared to excisional hemorrhoidectomy. - The freezing causes **vasoconstriction and thrombosis** of small vessels, reducing acute blood loss. - Delayed bleeding can rarely occur when eschar separates, but this is not the most significant disadvantage.
Question 3: All are true about erythema multiforme except which of the following?
- A. Associated with HSV
- B. Does not involve mucosa (Correct Answer)
- C. Target lesion
- D. Extensor involvement
Explanation: ***Does not involve mucosa*** - Erythema multiforme often presents with **mucosal involvement**, particularly in the oral cavity, which can range from mild erosions to severe blistering. - The presence of mucosal lesions, especially oral, ocular, or genital, is a key feature distinguishing more severe forms like **erythema multiforme major**. *Target lesion* - The **target lesion** (or iris lesion) is the hallmark dermatological finding in erythema multiforme, characterized by concentric rings of different colors. - This classic lesion is crucial for the clinical diagnosis of erythema multiforme. *Associated with HSV* - **Herpes Simplex Virus (HSV) infection** is the most common precipitating factor for erythema multiforme, especially for recurrent episodes. - The onset of lesions typically follows an HSV outbreak by several days to weeks. *Extensor involvement* - The rash of erythema multiforme commonly affects the **extensor surfaces of the extremities**, such as the dorsal hands, forearms, and shins. - While it can appear elsewhere, this distribution is a characteristic pattern.
Question 4: Identify the lesion: (Recent NEET Pattern 2016-17)
- A. Erythema multiforme (Correct Answer)
- B. Gianotti-Crosti syndrome
- C. Pityriasis rosea
- D. Acne rosacea
Explanation: ***Erythema multiforme*** - The image displays characteristic **targetoid lesions** with multiple concentric rings of color (erythema, edema, pallor), typical of **erythema multiforme**. - These lesions often appear suddenly, symmetrically, and commonly on the extremities, often triggered by infections (e.g., **herpes simplex virus**) or medications. *Gianotti-Crosti syndrome* - Characterized by **monomorphic, flesh-colored to erythematous papules** and papulovesicles, often on the cheeks, buttocks, and extensor surfaces of the limbs. - This condition is typically observed in **children** after viral infections and does not usually present with target lesions. *Pityriasis rosea* - Starts with a single **"herald patch,"** followed by smaller, oval, pinkish-red patches with fine scales, often arranged in a **"Christmas tree pattern"** on the trunk. - The morphology of the lesions in the image, specifically the targetoid appearance, is not consistent with pityriasis rosea. *Acne rosacea* - Marked by **facial erythema**, papules, pustules, and telangiectasias, primarily affecting the central face. - It does not present with the widespread, distinct target lesions seen in the image.
Question 5: 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 6: 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 7: 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 8: 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.
Question 9: A 19-year-old man develops a rash in the groin area. On examination, it is a large well-demarcated area of tan-brown discoloration around his left inguinal area. There is some scaling of the lesion when brushed with a tongue depressor. Which of the following is the most appropriate initial diagnostic test?
- A. Punch biopsy of skin
- B. Tzanck smear
- C. Potassium hydroxide (KOH) preparation of scrapings (Correct Answer)
- D. Blood culture for fungi
Explanation: ### Explanation The clinical presentation of a **well-demarcated, tan-brown, scaly lesion** in the inguinal area of a young man is highly suggestive of a superficial fungal infection, most likely **Tinea cruris** (jock itch). **1. Why KOH Preparation is Correct:** The **Potassium Hydroxide (KOH) preparation** is the gold standard initial diagnostic test for suspected fungal infections of the skin. When skin scrapings are treated with 10–20% KOH, the alkaline solution dissolves keratinocytes and debris, allowing for the clear visualization of fungal elements like **septate hyphae** or spores under a microscope. The "scaling when brushed" (positive scratch sign) indicates active fungal shedding or associated pityriasis, making KOH the most efficient and cost-effective bedside tool. **2. Why Other Options are Incorrect:** * **Punch Biopsy:** This is an invasive procedure used for deep inflammatory conditions or suspected malignancies. It is not indicated for a simple, superficial scaly rash. * **Tzanck Smear:** This is used for the diagnosis of **herpetic infections** (HSV, VZV) to look for multinucleated giant cells, not fungal infections. * **Blood Culture:** This is used for systemic/disseminated fungal infections (e.g., Candidemia). Superficial dermatophytosis does not involve the bloodstream. **3. High-Yield Clinical Pearls for NEET-PG:** * **Differential Diagnosis:** If the lesion showed **coral-red fluorescence** under Wood’s lamp, the diagnosis would be **Erythrasma** (caused by *Corynebacterium minutissimum*). * **Tinea Cruris vs. Candidiasis:** Tinea cruris typically **spares the scrotum**, whereas Candidal intertrigo involves the scrotum and presents with **satellite lesions**. * **Treatment:** First-line treatment for localized Tinea cruris is topical antifungals (e.g., Clotrimazole, Terbinafine). Avoid topical steroids as they lead to **Tinea incognito**.
Question 10: What is the best method to treat large port-wine hemangiomas?
- A. Radiotherapy
- B. Tattooing
- C. Excision with skin grafting
- D. Pulsed dye laser (Correct Answer)
Explanation: **Explanation:** **Pulsed Dye Laser (PDL)** is the gold standard treatment for Port-Wine Stains (PWS). The underlying medical concept is **Selective Photothermolysis**. The PDL (typically 585 or 595 nm) targets the chromophore **oxyhemoglobin** within the dilated dermal capillaries. The pulse duration is shorter than the thermal relaxation time of the vessels, allowing for targeted destruction of the vascular malformation without damaging the surrounding dermis. This results in significant lightening of the lesion with a very low risk of scarring. **Analysis of Incorrect Options:** * **Radiotherapy (A):** Historically used but now contraindicated due to the high risk of radiation-induced dermatitis, secondary malignancies (e.g., basal cell carcinoma), and permanent skin atrophy. * **Tattooing (B):** This involves injecting skin-colored pigments to mask the lesion. It is rarely used today because the pigment often looks unnatural, can shift over time, and does not address the underlying vascular pathology. * **Excision with skin grafting (C):** Port-wine stains are often large and involve the face. Surgical excision leads to significant scarring and "patchwork" cosmetic results, making it inferior to non-invasive laser therapy. **Clinical Pearls for NEET-PG:** * **Timing:** Treatment should ideally start in **infancy** (as early as weeks old) because the skin is thinner, the lesion is smaller, and the response to PDL is superior. * **Associated Syndromes:** Always rule out **Sturge-Weber Syndrome** (if the PWS involves the V1/V2 distribution of the trigeminal nerve) and **Klippel-Trenaunay Syndrome** (if involving an extremity with hypertrophy). * **Progression:** Unlike strawberry hemangiomas, PWS are **vascular malformations** that do not involute; they grow proportionately with the child and may become thickened or nodular (blebbing) in adulthood.
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