Onchocerciasis — MCQs
Pompholyx affects:
River blindness is caused by?
Mass Drug Administration is NOT routinely used as the primary strategy for:
What is the most likely diagnosis for a 15 mm hyperpigmented lesion on the shoulder that is enlarging and has hair growing from it?
Which of the following statements best describes the operational definition of onchocerciasis elimination?
Which of the following is NOT a feature of CMV retinitis?
Which of the following conditions is characterized by the sign of the groove?
A young female presents with a history of fever and a nodular lesion over the shin. Histopathology reveals foamy histiocytes with neutrophilic infiltration. There is no evidence of vasculitis. What is the most probable diagnosis?
A young tourist presents with an erythematous lesion on the cheek with central crusting after visiting a region endemic for a specific protozoal infection. What is the likely dermatological condition?
What is characteristic of donovanosis?
Onchocerciasis Indian Medical PG Practice Questions and MCQs
Question 1: Pompholyx affects:
- A. Groin
- B. Scalp
- C. Trunk
- D. Palms and soles (Correct Answer)
Explanation: ***Palms and soles*** - **Pompholyx**, also known as **dyshidrotic eczema**, is characterized by recurrent outbreaks of **vesicles and bullae** predominantly on the palms and soles. - These lesions are typically very **itchy** and can cause significant discomfort. *Groin* - Conditions like **tinea cruris** (jock itch) or **intertrigo** commonly affect the groin, presenting with erythema and scaling rather than vesicles. - While eczema can occur in the groin, classical pompholyx has a predilection for the acral regions. *Scalp* - The scalp is more commonly affected by conditions such as **seborrheic dermatitis** or **psoriasis**, which manifest as scaling, redness, and flaking. - Vesicular eruptions are rare on the scalp unless due to specific conditions like herpes zoster. *Trunk* - The trunk is a common site for various dermatoses, including **atopic dermatitis**, **psoriasis**, or **pityriasis rosea**, but these typically present with different morphologic features (e.g., plaques, patches). - Pompholyx is specific to palms and soles and does not usually involve the trunk.
Question 2: River blindness is caused by?
- A. Loa loa
- B. Ascaris
- C. B. malayi
- D. Onchocerca volvulus (Correct Answer)
Explanation: ***Onchocerca volvulus*** - **River blindness**, or **onchocerciasis**, is caused by the parasitic nematode *Onchocerca volvulus*. - This parasite is transmitted by the bite of infected **blackflies** (genus *Simulium*), which breed in fast-flowing rivers. *Loa loa* - *Loa loa* causes **Loiasis**, also known as African eye worm disease. - While it can manifest as an eye worm and cause itching and swelling, it does not typically lead to permanent blindness or the widespread skin lesions associated with river blindness. *Ascaris* - *Ascaris lumbricoides* causes **ascariasis**, an intestinal infection. - Symptoms are primarily gastrointestinal, such as abdominal pain, malnutrition, and, in severe cases, intestinal obstruction; it does not affect the eyes or cause blindness. *B. malayi* - *Brugia malayi* is one of the causes of **lymphatic filariasis**, also known as **elephantiasis**. - This disease primarily affects the lymphatic system, causing severe swelling in the limbs and genitals, but it does not cause blindness.
Question 3: Mass Drug Administration is NOT routinely used as the primary strategy for:
- A. Vitamin A Deficiency
- B. Scabies (Correct Answer)
- C. Lymphatic Filariasis
- D. Worm infestation
Explanation: ***Scabies*** - While **mass drug administration with oral ivermectin** has shown effectiveness in specific endemic outbreak settings, MDA is generally **not the primary recommended strategy** for routine scabies control in most public health contexts. - Scabies control typically prioritizes **case finding, contact tracing, simultaneous household treatment, and environmental decontamination**—which are more complex to implement than standard MDA programs. - Unlike the other conditions listed, scabies lacks well-established **routine MDA programs** at the scale of national public health initiatives, making it the least suitable option for MDA among these choices. *Vitamin A Deficiency* - **Vitamin A supplementation** through MDA is a **highly effective and widely implemented** WHO-recommended strategy to combat Vitamin A deficiency in at-risk populations, particularly children under 5 years. - Regular mass supplementation helps prevent **xerophthalmia** and reduces morbidity and mortality from infectious diseases. - This is a cornerstone of routine public health programs globally. *Lymphatic Filariasis* - **Lymphatic filariasis** is a classic example where MDA with anti-filarial drugs like **diethylcarbamazine (DEC), albendazole,** or **ivermectin** is the cornerstone strategy for interrupting transmission. - MDA is the **primary WHO-recommended approach** to achieve elimination of lymphatic filariasis, with established national programs in endemic countries. *Worm infestation* - **Mass deworming programs** using drugs like **albendazole** or **mebendazole** represent highly effective and well-established forms of MDA for controlling **soil-transmitted helminth infections**. - These routine programs significantly reduce disease burden in school-aged children, improving nutritional status, growth, and learning outcomes.
Question 4: What is the most likely diagnosis for a 15 mm hyperpigmented lesion on the shoulder that is enlarging and has hair growing from it?
- A. Melanocytic nevus
- B. Becker nevus (Correct Answer)
- C. Sebaceous nevus
- D. Comedo nevus
Explanation: ***Correct: Becker nevus*** This diagnosis is supported by the description of a **hyperpigmented lesion** that is **enlarging** and has **hair growing from it**, typically appearing during adolescence or young adulthood. **Becker nevus** often presents as an **irregular, hyperpigmented patch**, usually on the shoulder or upper trunk, and is characteristically associated with **hypertrichosis** (increased terminal hair growth). The combination of location (shoulder), enlargement, and hair growth in a 15 mm lesion is classic for Becker nevus. *Incorrect: Melanocytic nevus* While **melanocytic nevi** are hyperpigmented, they typically do not continue to **enlarge significantly** after childhood and generally do not develop new onset **hypertrichosis** as a primary feature. The size (15 mm) and progressive growth combined with hair development are more characteristic of a Becker nevus than a common melanocytic nevus. *Incorrect: Sebaceous nevus* **Sebaceous nevi** are typically **yellow-orange to tan, waxy plaques**, often on the scalp or face, with a cobblestone or papillomatous texture. They are not primarily characterized by **hyperpigmentation** and terminal hair growth, but rather by sebaceous gland proliferation. *Incorrect: Comedo nevus* A **comedo nevus** presents as a linear or unilateral group of **dilated follicular openings** filled with keratinous material, resembling blackheads. It is not characterized by diffuse **hyperpigmentation** or the increased terminal hair growth described in this case.
Question 5: Which of the following statements best describes the operational definition of onchocerciasis elimination?
- A. All interventions have been successfully implemented.
- B. There is no recrudescence of the disease after a defined period.
- C. All of the options are true.
- D. Transmission of O. volvulus has been reduced to a level where it cannot sustain itself in the population. (Correct Answer)
Explanation: **Transmission of O. volvulus has been reduced to a level where it cannot sustain itself in the population.** - This statement accurately reflects the definition of **disease elimination**, where the incidence of infection is reduced to zero in a defined geographical area, signifying that the **transmission cycle can no longer be sustained**. - For onchocerciasis, this means the **vector (blackfly)** is no longer transmitting the parasite (*Onchocerca volvulus*) between humans at a rate that allows the disease to persist. *All interventions have been successfully implemented.* - While successful implementation of interventions is crucial for elimination, it is a **process goal**, not the **ultimate outcome** or operational definition of elimination itself. - Elimination is defined by the **absence of sustained transmission**, which is a direct measure of disease burden, not intervention fidelity. *There is no recrudescence of the disease after a defined period.* - The **absence of recrudescence** (re-emergence) after a defined period is an important indicator of successful elimination validation, but it is a **consequence** or **part of the verification process**, not the primary operational definition. - The operational definition focuses on the **state of transmission** that leads to this sustained absence. *All of the options are true.* - This option is incorrect because only one of the provided statements accurately describes the **operational definition of elimination** in the context of parasitic diseases like onchocerciasis. - The other options describe aspects related to the elimination process or its verification, but not the core definition.
Question 6: Which of the following is NOT a feature of CMV retinitis?
- A. Perivasculitis
- B. Brush-fire appearance
- C. Immunosuppression
- D. Cracked mud appearance (Correct Answer)
Explanation: ***Cracked mud appearance*** - **"Cracked mud appearance"** is not a term used to describe CMV retinitis. The classic descriptions include **"pizza pie"**, **"cottage cheese and ketchup"**, and **"brush-fire"** appearances. - CMV retinitis presents with **necrotizing retinitis** with hemorrhages and granular opacification, not a cracked or atrophic pattern. - This option describes a **non-existent finding** in the context of CMV retinitis. *Immunosuppression* - **Immunosuppression**, especially due to **HIV/AIDS** (CD4 count <50 cells/μL), organ transplantation, or chemotherapy, is a **primary risk factor** for CMV retinitis. - It is crucial for the **reactivation** of latent CMV infection, leading to opportunistic disease. - While technically a predisposing condition rather than a "feature" of the disease itself, it is strongly associated with CMV retinitis. *Brush-fire appearance* - The **"brush-fire appearance"** is a classic description of CMV retinitis, referring to the **active leading edge** of the infection with confluent areas of necrosis and hemorrhage spreading across the retina. - This term captures the **fulminant necrotizing retinitis** with yellow-white retinal opacification and hemorrhages. *Perivasculitis* - **Perivasculitis**, or inflammation around the retinal blood vessels, is a **characteristic pathological feature** of CMV retinitis. - It often manifests as **frosted branch angiitis** (white sheathing around retinal vessels), which can be seen in severe cases.
Question 7: Which of the following conditions is characterized by the sign of the groove?
- A. Lymphogranuloma venereum (Correct Answer)
- B. Granuloma inguinale
- C. Syphilis
- D. Chancroid
Explanation: **Explanation:** **Lymphogranuloma venereum (LGV)** is caused by the **L1, L2, and L3 serovars of *Chlamydia trachomatis***. The "Sign of the Groove" (Greenblatt’s sign) is a pathognomonic clinical finding in the secondary stage of LGV. It occurs when the inguinal and femoral lymph nodes enlarge simultaneously, separated by the rigid **inguinal ligament**. This creates a visible depression or "groove" between the two groups of inflamed lymph nodes. **Analysis of Incorrect Options:** * **B. Granuloma Inguinale (Donovanosis):** Caused by *Klebsiella granulomatis*. It presents with painless, beefy-red, velvety ulcers. It is characterized by "pseudobuboes" (subcutaneous granulation tissue) rather than true lymphadenopathy. * **C. Syphilis:** Primary syphilis presents with a painless, indurated "hard chancre." While it causes bilateral inguinal lymphadenopathy, the nodes are discrete, rubbery, and do not form a groove. * **D. Chancroid:** Caused by *Haemophilus ducreyi*. It presents with painful, soft ulcers and painful inflammatory buboes that are usually unilateral and may suppurate, but they do not form the characteristic groove sign. **High-Yield Clinical Pearls for NEET-PG:** * **Stages of LGV:** Primary (painless papule/ulcer), Secondary (Inguinal syndrome with the Groove sign), and Tertiary (Genito-anorectal syndrome/Elephantiasis). * **Diagnosis:** Frei test (historical), NAAT (current gold standard), and **Donovan bodies** (safety-pin appearance) are seen in Donovanosis, NOT LGV. * **Treatment:** Doxycycline (100 mg BID for 21 days) is the drug of choice for LGV.
Question 8: A young female presents with a history of fever and a nodular lesion over the shin. Histopathology reveals foamy histiocytes with neutrophilic infiltration. There is no evidence of vasculitis. What is the most probable diagnosis?
- A. Sweet's Syndrome
- B. Erythema nodosum (Correct Answer)
- C. Erythema nodosum leprosum
- D. Behcet's syndrome
Explanation: ### Explanation **Correct Answer: B. Erythema nodosum** **Why it is correct:** Erythema nodosum (EN) is the most common form of **septal panniculitis**. Clinically, it presents as tender, erythematous nodules typically located over the **pretibial area (shins)**, often accompanied by fever and malaise. Histopathologically, early lesions show edema and neutrophilic infiltration of the septa. As the lesion evolves, it is characterized by **Miescher’s radial granulomas**—small clusters of spindle-shaped or **foamy histiocytes** surrounding a central cleft. The absence of vasculitis is a hallmark feature that distinguishes EN from other forms of panniculitis. **Why the other options are incorrect:** * **A. Sweet’s Syndrome:** This is a neutrophilic dermatosis characterized by "juicy" erythematous plaques and high fever. Histology shows dense dermal neutrophilic infiltrate with papillary dermal edema, but it is not a primary panniculitis and does not typically present with foamy histiocytes in the septa. * **C. Erythema nodosum leprosum (ENL):** While ENL also presents with tender nodules and fever, it is a Type 2 Lepra reaction. Histologically, it is a **lobular panniculitis** and, crucially, it **must show evidence of vasculitis** (leukocytoclastic vasculitis) and the presence of *M. leprae* (AFB positive). * **D. Behcet’s syndrome:** While it can cause EN-like lesions, the systemic involvement (oral/genital ulcers, uveitis) and the characteristic histopathology (often showing vasculitis) do not fit the isolated description provided. **NEET-PG High-Yield Pearls:** * **Most common cause of EN:** Idiopathic (followed by Streptococcal infections, Sarcoidosis, and TB). * **Histopathology Key:** Septal panniculitis **without** vasculitis = Erythema Nodosum. * **Löfgren Syndrome:** Triad of EN, bilateral hilar lymphadenopathy, and arthritis (highly suggestive of Sarcoidosis). * **Miescher’s Radial Granulomas:** Pathognomonic histological finding for EN.
Question 9: A young tourist presents with an erythematous lesion on the cheek with central crusting after visiting a region endemic for a specific protozoal infection. What is the likely dermatological condition?
- A. Cutaneous Leishmaniasis (Correct Answer)
- B. Systemic Lupus Erythematosus
- C. Lupus vulgaris
- D. Chilblains
Explanation: ### Explanation **Correct Option: A. Cutaneous Leishmaniasis** Cutaneous Leishmaniasis (CL), often referred to as "Oriental Sore" or "Delhi Boil," is caused by the protozoan *Leishmania* species and transmitted by the bite of an infected **female sandfly (*Phlebotomus*)**. The classic presentation begins as a small erythematous papule at the inoculation site (usually exposed areas like the face), which evolves into a nodule and eventually develops **central crusting** or ulceration with a raised, indurated border. The history of travel to an endemic region is a crucial diagnostic clue. **Why Incorrect Options are Wrong:** * **B. Systemic Lupus Erythematosus (SLE):** Typically presents with a "malar rash" (butterfly distribution) that spares the nasolabial folds. It is an autoimmune condition, not associated with travel to protozoal endemic areas or central crusting. * **C. Lupus Vulgaris:** This is a chronic form of cutaneous tuberculosis. While it affects the face, it typically presents as "apple-jelly" nodules on diascopy and follows a very chronic, progressive course rather than an acute post-travel presentation. * **D. Chilblains (Pernio):** An inflammatory response to cold, damp conditions. It presents as itchy, purple-red bumps on fingers or toes, not as a crusted facial lesion following tropical travel. **High-Yield Clinical Pearls for NEET-PG:** * **Vector:** Female Sandfly (*Phlebotomus*). * **Diagnosis:** Skin biopsy or slit-skin smear showing **LD bodies** (Leishman-Donovan bodies) within macrophages. * **Treatment of Choice:** Intralesional or systemic **Sodium Stibogluconate** (Pentavalent antimonials) or Miltefosine. * **Volcano Sign:** The appearance of a crusted ulcer with a central pit is often described as the "volcano sign."
Question 10: What is characteristic of donovanosis?
- A. Pseudolymphadenopathy (Correct Answer)
- B. Penicillin is used for treatment
- C. Painful ulcer
- D. Suppurative lymphadenopathy
Explanation: **Donovanosis (Granuloma Inguinale)** is a chronic, progressive bacterial infection caused by the intracellular Gram-negative organism *Klebsiella granulomatis*. ### **Explanation of the Correct Answer** **A. Pseudolymphadenopathy:** This is the hallmark of Donovanosis. Unlike other STIs, the infection does not typically involve the regional lymph nodes. Instead, the subcutaneous granulation tissue spreads along the inguinal folds, causing firm, non-tender swellings that mimic enlarged lymph nodes. These are called **"pseudobuboes."** ### **Why Other Options are Incorrect** * **B. Penicillin is used for treatment:** Penicillin is ineffective. The CDC-recommended first-line treatment is **Azithromycin** (1g weekly or 500mg daily for at least 3 weeks). * **C. Painful ulcer:** Donovanosis is classically **painless**. It presents as beefy-red, friable (bleeds easily on touch) ulcers with rolled-out edges. Pain only occurs if there is secondary bacterial superinfection. * **D. Suppurative lymphadenopathy:** This is characteristic of **Lymphogranuloma Venereum (LGV)** or **Chancroid**, where true fluctuant buboes form. Donovanosis lacks true lymph node involvement. ### **High-Yield Clinical Pearls for NEET-PG** * **Donovan Bodies:** Diagnosis is confirmed by seeing "safety-pin" appearing organisms within large macrophages on a Giemsa or Wright stain (crush smear). * **Clinical Appearance:** Often described as "beefy-red" granulation tissue with a "velvety" texture. * **Extragenital Involvement:** Can occur in the mouth, liver, or bone via autoinoculation or hematogenous spread. * **Mnemonic:** Remember the **"4 Ps"** of Donovanosis: **P**ainless, **P**rogressive, **P**seudobuboes, and **P**olymorphic (various clinical types like ulcerogranulomatous, hypertrophic, etc.).
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