Tungiasis — MCQs
Cutaneous larva migrans is caused by which organism?
A 65-year-old man presented with skin lesions on his chest and left arm and shoulder, six weeks after returning from a vacation in Belize, where he spent time at the beach in the rainforest. The lesions occasionally stung, drained dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. What is the cause of this condition?
Which of the following is the carrying agent for Lyme disease?
Man is the only host for
Which of the following statements about pediculosis pubis is MOST accurate?
A 65-year old man presented with skin lesions on his chest and left arm and shoulder six weeks after returning from a vacation in Belize at the beach in the rain forest. The lesions occasionally stung, drained a dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. The larvae coming out of the pores are-
Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
Meyers Kouwenaar syndrome is a synonym for ?
Identify the lesion:
Which of the following conditions is characterized by the sign of the groove?
Tungiasis Indian Medical PG Practice Questions and MCQs
Question 1: Cutaneous larva migrans is caused by which organism?
- A. Strongyloides
- B. Toxocara canis
- C. Ancylostoma braziliense (Correct Answer)
- D. Necator americanus
Explanation: ***Ancylostoma braziliense*** - This **hookworm** species commonly found in dogs and cats is the most frequent cause of **cutaneous larva migrans** in humans. - The larvae penetrate the skin but cannot complete their life cycle in humans, instead migrating aimlessly creating **serpiginous tracks**. *Strongyloides* - **_Strongyloides stercoralis_** causes **strongyloidiasis**, which presents with a rapidly advancing (up to 10 cm/hr) migratory rash known as **larva currens**, and not the slower cutaneous larva migrans. - It differs from cutaneous larva migrans in its ability to complete its life cycle in humans, leading to **autoinfection**. *Toxocara canis* - **_Toxocara canis_** is the causative agent of **visceral larva migrans** and **ocular larva migrans**, not cutaneous larva migrans. - In visceral larva migrans, larvae migrate through internal organs, causing symptoms like **hepatomegaly** and **eosinophilia**. *Necator americanus* - This is a human hookworm that can cause **iron deficiency anemia** due to chronic blood loss in the intestines. - While its larvae can penetrate the skin, causing a transient itchy rash known as **ground itch**, they do not cause the prolonged, migratory cutaneous larva migrans.
Question 2: A 65-year-old man presented with skin lesions on his chest and left arm and shoulder, six weeks after returning from a vacation in Belize, where he spent time at the beach in the rainforest. The lesions occasionally stung, drained dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. What is the cause of this condition?
- A. Cutaneous leishmaniasis
- B. Tungiasis
- C. Onchocerciasis
- D. Bot fly (Correct Answer)
Explanation: ***Bot fly*** - The presence of a **single, moving larva** observed through a central pore in nodular skin lesions, after travel to a tropical region (Belize), is highly characteristic of **myiasis caused by the bot fly (Dermatobia hominis)**. - The symptoms like stinging, dark exudates, and enlargement despite antibiotics are consistent with the larva feeding and growing within the host. *Tungiasis* - Caused by the **sand flea Tunga penetrans**, which burrows into the skin, typically on the feet, causing intense itching and pain. - It presents as a **pigmented nodule** with a central black dot, but **no visible moving larva**. *Cutaneous leishmaniasis* - Presents as **chronic skin ulcers or nodules** that can be slow-healing and often have raised borders. - Diagnosis is confirmed by identifying **amastigotes** in tissue samples, not by observing a moving larva. *Onchocerciasis* - Caused by the filarial nematode **Onchocerca volvulus**, transmitted by blackflies, leading to **subcutaneous nodules (onchocercomas)** and skin changes. - It does not involve a single, macroscopic, moving larva visible through a central pore.
Question 3: Which of the following is the carrying agent for Lyme disease?
- A. Anopheles
- B. Ixodes scapularis ticks (Correct Answer)
- C. Louse
- D. Rat flea
Explanation: ***Ixodes scapularis ticks*** - *Ixodes scapularis* ticks (deer ticks) are the primary **vectors for Lyme disease** (caused by *Borrelia burgdorferi*) in North America [1]. - In Europe, *Ixodes ricinus* is the main vector for Lyme disease. - Lyme disease presents with characteristic **erythema migrans** rash, followed by potential neurological, cardiac, and arthritic complications [1]. - Lyme arthritis commonly affects large joints, particularly the **knee**, causing inflammatory arthritis [1]. *Anopheles* - **Anopheles mosquitoes** are the primary vectors for **malaria**, not Lyme disease [2]. - Malaria is caused by *Plasmodium* parasites and presents with fever, chills, and hemolytic anemia [2]. *Louse* - **Lice** are vectors for diseases such as **epidemic typhus** (caused by *Rickettsia prowazekii*) and **relapsing fever** (caused by *Borrelia recurrentis*) [3]. - They are not associated with the transmission of Lyme disease. *Rat flea* - **Rat fleas** (e.g., *Xenopsylla cheopis*) are the primary vectors for **bubonic plague** (caused by *Yersinia pestis*) and **murine typhus**. - These insects do not transmit Lyme disease. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 389-390. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, p. 400. [3] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Infectious Diseases, pp. 392-393.
Question 4: Man is the only host for
- A. Onchocerca volvulus
- B. Trichuris trichiura
- C. Wuchereria bancrofti (Correct Answer)
- D. Dracunculus medinensis
Explanation: ***Wuchereria bancrofti*** - This parasite is largely **restricted to humans** as its definitive host, causing **lymphatic filariasis**. - Its life cycle involves transmission via mosquitoes, but it relies solely on humans for the maturation of adult worms and the production of microfilariae. *Onchocerca volvulus* - While humans are the primary definitive hosts for **Onchocerca volvulus**, leading to **onchocerciasis** or **river blindness**, certain **simian primates** have also been found to harbor the parasite, making humans not the *exclusive* host. - The parasite is transmitted by **blackflies**. *Trichuris trichiura* - This parasite, commonly known as the **human whipworm**, primarily infects humans. - However, **other primates** like monkeys and apes can also be infected, thus humans are not the sole host. *Dracunculus medinensis* - While humans are the main and most well-known definitive host for **Dracunculus medinensis** (guinea worm), **dogs** and **other carnivores** have also been identified as hosts. - The infection is acquired by ingesting **copepods** containing larvae in contaminated water.
Question 5: Which of the following statements about pediculosis pubis is MOST accurate?
- A. Eggs (nits) attached to hair shafts confirm diagnosis (Correct Answer)
- B. It commonly infests scalp hair
- C. It requires systemic antibiotic treatment
- D. It is more contagious than other types of lice
Explanation: ***Eggs (nits) attached to hair shafts confirm diagnosis*** - The presence of **nits (eggs)** firmly attached to the hair shafts, particularly in the pubic region, is a **definitive diagnostic criterion** for pediculosis pubis. - These nits are typically oval, white or grayish, and cannot be easily removed, distinguishing them from dandruff. *It commonly infests scalp hair* - **Pediculosis pubis**, caused by *Pthirus pubis* (pubic louse or crab louse), primarily infests **coarse body hair**, most commonly in the pubic area. - **Scalp hair** is typically infested by *Pediculus humanus capitis* (head louse), which is a different species. *It requires systemic antibiotic treatment* - Pediculosis pubis is caused by an **ectoparasite** (louse), not a bacterial infection, and therefore does not require **systemic antibiotic treatment**. - Treatment involves topical insecticides like permethrin or malathion, and physical removal of lice and nits. *It is more contagious than other types of lice* - All types of lice are **highly contagious**, but pediculosis pubis is primarily transmitted through **sexual contact** or close bodily contact, making it a sexually transmitted infection (STI). - While easily spread, there is no evidence to suggest it is inherently more contagious than head lice, which spread easily through casual contact, especially among children.
Question 6: A 65-year old man presented with skin lesions on his chest and left arm and shoulder six weeks after returning from a vacation in Belize at the beach in the rain forest. The lesions occasionally stung, drained a dark exudates, and enlarged despite two weeks of treatment with cephalexin. The patient had no constitutional symptoms. Physical examination revealed five nodules of varying sizes with surrounding erythema and a central pore through which a single, moving larva was observed. The larvae coming out of the pores are-
- A. Loa loa
- B. Diphyllobothrium latum
- C. Dermatobia hominis (Correct Answer)
- D. Dracunculus medinensis
Explanation: ***Dermatobia hominis*** - The description of **cutaneous nodules** with a central pore from which a **moving larva** is observed, particularly after travel to a tropical region like Belize, is classic for **furuncular myiasis** caused by **Dermatobia hominis** larvae (human botfly). - The **"occasional stinging"** and **"dark exudate"** are characteristic symptoms of the larva burrowing in the skin and secreting waste products. *Loa loa* - **Loa loa** (African eye worm) is a filarial nematode that migrates through **subcutaneous tissues** and occasionally across the eye, causing **Calabar swellings**. - It does not present as a **furuncular lesion** with a visible central moving larva emerging from a pore. *Diphyllobothrium latum* - **Diphyllobothrium latum** is a **tapeworm** that infects the intestines and is acquired by consuming undercooked infected fish. - It causes gastrointestinal symptoms and can lead to **vitamin B12 deficiency**, but it does not produce **skin lesions with moving larvae**. *Dracunculus medinensis* - **Dracunculus medinensis** (guinea worm) infection typically results in a **painful blister** on the lower limbs, from which the female worm emerges to release larvae when exposed to water. - While it involves a skin lesion, the presentation of **multiple nodules with a central pore revealing a moving larva** is not consistent with **dracunculiasis**.
Question 7: Statement 1 - A 59-year-old patient presents with flaccid bullae. Histopathology shows a suprabasal acantholytic split. Statement 2 - The row of tombstones appearance is diagnostic of Pemphigus vulgaris.
- A. Statements 1 & 2 are correct, 2 is not explaining 1 (Correct Answer)
- B. Statements 1 and 2 are correct and 2 is the correct explanation for 1
- C. Statements 1 and 2 are incorrect
- D. Statement 1 is incorrect
Explanation: ***Correct: Statements 1 & 2 are correct, 2 is not explaining 1*** **Analysis of Statement 1:** - A 59-year-old patient with **flaccid bullae** and **suprabasal acantholytic split** on histopathology is the classic presentation of **Pemphigus vulgaris** - The flaccid (easily ruptured) nature of bullae distinguishes it from tense bullae seen in bullous pemphigoid - The suprabasal location of the split (just above the basal layer) with acantholysis (loss of cell-to-cell adhesion) is pathognomonic - **Statement 1 is CORRECT** ✓ **Analysis of Statement 2:** - The **"row of tombstones" or "tombstone appearance"** is indeed a diagnostic histopathological feature of Pemphigus vulgaris - This appearance results from basal keratinocytes remaining attached to the basement membrane while suprabasal cells separate due to acantholysis - The intact basal cells standing upright resemble a row of tombstones - **Statement 2 is CORRECT** ✓ **Does Statement 2 explain Statement 1?** - Statement 2 describes a **histopathological appearance** (tombstone pattern) that is a **consequence** of the suprabasal split - However, it does NOT explain the **underlying cause** of the flaccid bullae or the suprabasal split - The true explanation involves **IgG autoantibodies against desmoglein 3 (and desmoglein 1)**, which attack intercellular adhesion structures (desmosomes), causing **acantholysis** - Therefore, **Statement 2 does NOT explain Statement 1** ✗ *Incorrect: Statement 2 is the correct explanation for Statement 1* - While both statements describe features of Pemphigus vulgaris, the tombstone appearance is a descriptive finding, not an explanatory mechanism *Incorrect: Statements 1 and 2 are incorrect* - Both statements are medically accurate descriptions of Pemphigus vulgaris features *Incorrect: Statement 1 is incorrect* - Statement 1 correctly describes the cardinal clinical and histopathological features of Pemphigus vulgaris
Question 8: Meyers Kouwenaar syndrome is a synonym for ?
- A. Occult filariasis (Correct Answer)
- B. Larva migrans
- C. Tropical pulmonary eosinophilia
- D. Cutaneous allergic reactions to Ascariasis
Explanation: ***Occult filariasis*** - **Meyers Kouwenaar syndrome** is a historical term used to describe **occult filariasis**, particularly those cases involving the lymphatics without the presence of microfilariae in peripheral blood. - This syndrome is characterized by **chronic lymphatic obstruction** and **eosinophilia**, often due to an immunological response to filarial antigens. *Larva migrans* - **Larva migrans** refers to conditions (cutaneous or visceral) caused by the migration of **nematode larvae** in human tissues. - It describes the migratory phase of the parasite and is not a synonym for occult filariasis, which is a specific clinical manifestation of filarial infection. *Tropical pulmonary eosinophilia* - **Tropical pulmonary eosinophilia (TPE)** is a distinct clinical syndrome characterized by **nocturnal cough**, **dyspnea**, and **marked peripheral eosinophilia**, caused by an allergic reaction to Wuchereria bancrofti or Brugia malayi microfilariae that are trapped in the lungs. - While it is a form of occult filariasis (microfilariae are absent in the blood), it is a specific presentation and not a general synonym for Meyers Kouwenaar syndrome, which typically refers to lymphatic involvement. *Cutaneous allergic reactions to Ascariasis* - **Cutaneous allergic reactions to Ascariasis** typically involve manifestations like **urticaria** or **angioedema** due to migration of Ascaris larvae or exposure to adult worms. - This is a reaction to a different parasitic infection (Ascaris lumbricoides) and does not relate to filariasis.
Question 9: Identify the lesion:
- A. Psoriasis
- B. Dermatitis herpetiformis
- C. Erythema marginatum
- D. Dermatomyositis (Correct Answer)
Explanation: ***Dermatomyositis*** - The image shows **Gottron's papules** over the extensor surfaces of the elbows, which are characteristic of dermatomyositis. These are violaceous, erythematous, flat-topped papules. - While typically found on the **dorsum of the hands** over the MCP and IP joints, they can also occur on elbows, knees, and ankles. *Psoriasis* - Psoriasis typically presents with **well-demarcated erythematous plaques** covered with silvery scales, especially on extensor surfaces. - The lesions in the image lack the characteristic **silvery scaling** of psoriasis. *Dermatitis herpetiformis* - This condition presents with intensely **itchy, polymorphic lesions**, including vesicles, bullae, and excoriations, arranged in a symmetrical fashion, often on extensor surfaces. - The lesions in the image are papular and nodular, not exhibiting the characteristic **vesicular or bullous eruption** of dermatitis herpetiformis. *Erythema marginatum* - Erythema marginatum is a **transient, non-pruritic erythematous rash** with serpiginous borders and central clearing, typically seen in **acute rheumatic fever**. - The lesions in the image are fixed papules/nodules without the characteristic migrating or rapidly changing appearance of erythema marginatum.
Question 10: 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.
Want unlimited practice?
Get full access to all questions, explanations, and performance tracking.
Start For Free