INI-CET 2022 Practice Questions

Q: A 12-week pregnant woman on multidrug therapy for leprosy presents with type 2 lepra reaction. What is the treatment of choice for this patient?

Continue MDT and add oral steroids. ***Continue MDT and add oral steroids*** - **Type 2 lepra reactions (erythema nodosum leprosum)** are inflammatory complications of leprosy and require systemic anti-inflammatory treatment. **Oral corticosteroids** are the mainstay for managing these reactions, particularly in pregnant patients where other immunomodulators are contraindicated. - **Multidrug therapy (MDT)** for leprosy should be continued throughout the reaction, even during pregnancy, to ensure eradication of *Mycobacterium leprae* and prevent drug resistance. Interrupting MDT can lead to relapse and increased neurological damage. *Antibiotics* - This option is incorrect because the type 2 lepra reaction is an **immunological complication** of leprosy, not a bacterial infection requiring additional antibiotics beyond the standard MDT. - The symptoms are due to the immune system's response to dying bacteria, not a new or secondary bacterial infection. *Stop MDT and start oral steroids* - Stopping MDT is inappropriate as the underlying **leprosy infection** still needs to be treated to prevent further progression and drug resistance. - While steroids are crucial for managing the reaction, stopping MDT would compromise the **curative treatment** for leprosy. *Thalidomide* - **Thalidomide** is highly effective in treating **erythema nodosum leprosum (ENL)**. - However, it is an absolute **contraindication** during pregnancy due to its severe **teratogenicity**, causing severe birth defects.

Q: Match the following scale types with their lesions. | Scales | Lesions | | :-- | :-- | | 1. Collarette scales | a. Pityriasis versicolour | | 2. Silvery scales | b. Pityriasis rosea | | 3. Mica-like scales | c. Psoriasis | | 4. Branny scales | d. Pityriasis lichenoides |

1-b, 2-c, 3-d, 4-a. ***1-b, 2-c, 3-d, 4-a*** - **Collarette scales** are pathognomonic of **Pityriasis rosea**, appearing as fine, trailing scales around the periphery of oval lesions in a "Christmas tree" distribution. - **Silvery scales** are the classic hallmark of **Psoriasis**, presenting as thick, adherent, silvery-white scales overlying well-demarcated erythematous plaques. - **Mica-like scales** are characteristic of **Pityriasis lichenoides**, appearing as thick, shiny, adherent scales that can be peeled off like mica sheets. - **Branny scales** are typical of **Pityriasis versicolor**, presenting as fine, powdery scales caused by **Malassezia** yeast overgrowth. *1-d, 2-c, 3-a, 4-b* - Incorrectly matches **collarette scales with Pityriasis lichenoides**, which typically presents with mica-like scales, not collarette scales. - Misassociates **mica-like scales with Pityriasis versicolor**, which characteristically has branny (fine, powdery) scales. *1-c, 2-b, 3-d, 4-a* - Wrongly pairs **collarette scales with Psoriasis**, which is known for thick silvery scales, not peripheral collarette scales. - Incorrectly matches **silvery scales with Pityriasis rosea**, which has collarette scales at lesion periphery, not silvery scales. *1-a, 2-b, 3-d, 4-c* - Falsely associates **collarette scales with Pityriasis versicolor**, which has branny scales from yeast infection, not collarette scales. - Mismatches **branny scales with Psoriasis**, which has characteristic thick silvery scales, not fine powdery scales.

Q: A 60-year-old patient presents with unilateral vesicular lesions in a dermatomal distribution on the torso. The lesions are painful and appeared over the past 2-3 days, progressing from erythematous patches to fluid-filled vesicles. The patient reports prodromal burning and tingling sensation in the affected area. Which of the following is the most likely diagnosis?

Herpes zoster infection. ***Herpes zoster infection*** - The patient's presentation of **unilateral vesicular lesions** in a **dermatomal distribution**, accompanied by severe pain and a **prodromal burning and tingling sensation**, is classic for herpes zoster (shingles). - Herpes zoster results from the **reactivation of latent varicella-zoster virus (VZV)** in a sensory ganglion, leading to painful rash along the affected nerve path. *Irritant contact dermatitis* - This condition involves inflammation due to direct contact with an irritating substance, often presenting with **eczematous lesions**, redness, itching, and sometimes vesicles. - However, it typically lacks the characteristic **dermatomal distribution** and severe neuropathic pain seen in herpes zoster. *Allergic contact dermatitis* - Allergic contact dermatitis is an immune-mediated reaction to an allergen, causing intensely pruritic, erythematous, and often **vesicular or bullous eruptions** that tend to spread beyond the initial contact area over time. - While it can cause vesicles, it does not follow a **dermatomal pattern** and is usually very itchy, rather than primarily painful and burning, with a distinct prodrome. *Herpes Simplex Infection* - Herpes simplex virus (HSV) infections also cause **vesicular lesions** but typically present as clusters of vesicles on an **erythematous base** in a localized area, often around the mouth (cold sores) or genitals. - Unlike herpes zoster, HSV lesions are usually **recurrent** in the same small area and typically do not exhibit a widespread, **unilateral dermatomal pattern** or the associated severe, persistent neuropathic pain.

Q: Antigen presented on MHC class I molecules activates which of the following cells?

Cytotoxic T cells. ***Cytotoxic T cells*** - **MHC class I** molecules present **intracellular antigens** (e.g., viral or tumor antigens) to **CD8+ T cells** (cytotoxic T cells). - This binding activates the cytotoxic T cells, leading to the destruction of the **infected** or **abnormal host cell**. *NK cells* - **Natural Killer (NK) cells** recognize and kill target cells that have **reduced or absent MHC class I** expression, which often occurs in virally infected or tumor cells, not cells presenting antigens on MHC class I. - They are part of the **innate immune system** and do not require prior sensitization or MHC-peptide presentation for activation. *Helper cells* - **Helper T cells** (CD4+ T cells) recognize antigens presented on **MHC class II** molecules, typically expressed by **antigen-presenting cells** (APCs) like macrophages, B cells, and dendritic cells. - Their primary role is to **orchestrate immune responses** by releasing cytokines. *B cells* - **B cells** are primarily involved in **humoral immunity**, producing antibodies after recognizing specific antigens directly via their B cell receptors or with T cell help. - While they can present antigens on **MHC class II** to helper T cells, direct antigen binding to **MHC class I** does not activate B cells.

Q: Which of the following statements regarding the given image is correct?

Majority of infections are asymptomatic in humans. ***Majority of infections are asymptomatic in humans*** - The image depicts an egg of *Hymenolepis nana*, also known as the **dwarf tapeworm**, identifiable by its characteristic **polar filaments** and **polar thickenings** on the inner membrane. - While heavy infections can cause symptoms, most *Hymenolepis nana* infections are **asymptomatic** or present with only mild, nonspecific gastrointestinal complaints. *Infection is acquired by ingestion of undercooked freshwater fish* - Infection with *Hymenolepis nana* is typically acquired through the **ingestion of eggs** directly from contaminated food or water, or via **fecally-contaminated hands**. - Ingestion of undercooked freshwater fish is associated with trematode (fluke) infections like **Clonorchis sinensis** or **Opisthorchis viverrini**, not *Hymenolepis nana*. *Albendazole is the drug of choice* - The drug of choice for *Hymenolepis nana* infection is **Praziquantel**, given as a single dose. - While albendazole might be used for some helminth infections, it is **less effective** than praziquantel for *Hymenolepis nana*. *It is the largest tapeworm infecting humans* - *Hymenolepis nana* is known as the **dwarf tapeworm** and is generally the **smallest tapeworm** that infects humans, typically measuring a few centimeters in length. - The largest tapeworm infecting humans is *Diphyllobothrium latum* (fish tapeworm), which can reach lengths of several meters.

Q: Which of the following are acid-fast staining organisms? 1. Nocardia 2. Mycobacterium leprae 3. Actinomyces 4. Cryptosporidium parvum 5. Isospora belli

1,2,4,5. ***1,2,4,5*** - **Nocardia**, **Mycobacterium leprae**, **Cryptosporidium parvum**, and **Isospora belli** all exhibit acid-fast properties, meaning they retain carbolfuchsin stain even after decolorization with acid alcohol due to the presence of mycolic acid in their cell walls or unique cyst structures. - This characteristic is crucial for their identification in clinical microbiology and distinguishes them from many other microorganisms. *1,2,3* - This option incorrectly includes **Actinomyces** as an acid-fast organism. **Actinomyces** are Gram-positive, filamentous bacteria that are **not acid-fast**. - While Nocardia and Mycobacterium leprae are acid-fast, the inclusion of Actinomyces makes this choice incorrect. *1,2,3,4,5* - This option is incorrect because it includes **Actinomyces** as an acid-fast organism, which is not true. - **Actinomyces** are Gram-positive, non-acid-fast bacteria, differentiating them from the other listed organisms that do possess acid-fast properties. *3,4,5* - This option is incorrect because it excludes **Nocardia** and **Mycobacterium leprae**, both of which are prominent acid-fast organisms. - While Cryptosporidium parvum and Isospora belli are acid-fast, the omission of Nocardia and Mycobacterium leprae makes this answer incomplete and incorrect.

Q: An HIV patient came to the clinic with a history of diarrhea. Stool microscopy showed the oocysts that were 4-8 µm in size. The image is shown below. Identify the organism.

Cryptosporidium. ***Cryptosporidium*** - **Cryptosporidium** is a common cause of **diarrhea** in **HIV patients**, and its oocysts are typically **acid-fast** and measure **4-6 µm** in size, consistent with the description. - The organism causes **watery diarrhea**, abdominal cramps, and malabsorption, especially in immunocompromised individuals. *Microsporidium* - **Microsporidium** species cause **diarrhea** in HIV patients, but their spores are much smaller, typically **1-2 µm** in size, and require specialized stains for visualization. - They are obligate intracellular parasites that primarily infect enterocytes, leading to malabsorption. *Cyclospora* - **Cyclospora cayetanensis** also causes **diarrhea** in HIV patients, but its oocysts are larger than **Cryptosporidium**, typically measuring **8-10 µm**, and are also acid-fast. - Infection is often associated with contaminated fresh produce and results in prolonged watery diarrhea. *Isospora* - **Cystoisospora belli** (formerly Isospora belli) oocysts are even larger, ranging from **20-30 µm** in length, and are typically ellipsoidal in shape. - These oocysts are also acid-fast and cause severe, protracted diarrhea in immunocompromised individuals.

Q: The image below shows the life cycle of a virus. Which of the proteins of the virus act as oncogenes?

E6, E7. ***E6, E7*** - The **E6** and **E7** proteins of high-risk human papillomaviruses (HPVs) are considered **oncogenes** because they interfere with critical tumor suppressor pathways [1][2]. - **E6** promotes the degradation of **p53**, a tumor suppressor protein, while **E7** inactivates **retinoblastoma protein (pRb)**, leading to uncontrolled cell proliferation and increased risk of malignant transformation [2]. *L1, L2* - **L1** and **L2** are **late proteins** (structural proteins) that form the **viral capsid** (outer shell) of the HPV virion. - They are essential for assembling new viral particles but do not directly contribute to the oncogenic process by disrupting host cell cycle regulation. *E1, E2, E5* - **E1** is involved in **viral DNA replication**, acting as a helicase and ATPase. - **E2** regulates **viral gene expression** and DNA replication, while **E5** is a small transmembrane protein that can contribute to cell growth but is generally considered less potent in oncogenesis than E6 and E7, and its exact role varies by HPV type. *E1, E2* - **E1** is critical for **viral DNA replication**, and **E2** regulates viral gene transcription and DNA replication. - While important for the viral life cycle, neither E1 nor E2 are the primary drivers of oncogenesis in the way E6 and E7 are, as they do not directly target key tumor suppressor proteins like p53 and pRb. **References:** [1] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. The Female Genital Tract, pp. 1007-1008. [2] Kumar V, Abbas AK, et al.. Robbins and Cotran Pathologic Basis of Disease. 9th ed. Neoplasia, pp. 334-335.

Q: What is the ratio of T cells to B cells in a healthy adult?

3:1. ***3:1*** - In healthy adults, a typical peripheral blood sample shows a **predominance of T cells** over B cells. - This ratio reflects the differing roles and distributions of these lymphocytes; **T cells are more numerous** in circulation. *1:3* - This ratio would indicate **more B cells than T cells**, which is not typical for peripheral blood in a healthy individual. - An inversion of the usual T:B cell ratio could suggest certain disease states, such as specific **lymphoid malignancies**. *1:1* - While possible in some specific lymphoid tissues, a **1:1 ratio is not the standard** for circulating T and B cells in healthy adults. - This ratio would represent a **significantly higher proportion of B cells** than usually found in peripheral blood. *1:2* - This ratio implies **twice as many B cells as T cells**, which is significantly skewed compared to normal physiological levels in peripheral blood. - Such a high proportion of B cells is typically observed in states of **B-cell proliferation** or specific immune dysregulation.

Question 1

A 12-week pregnant woman on multidrug therapy for leprosy presents with type 2 lepra reaction. What is the treatment of choice for this patient?

Accepted Answer

Continue MDT and add oral steroids

Answer

Antibiotics

Answer

Stop MDT and start oral steroids

Answer

Thalidomide

Question 2

Match the following scale types with their lesions.

Accepted Answer

1-b, 2-c, 3-d, 4-a

Answer

1-d, 2-c, 3-a, 4-b

Answer

1-c, 2-b, 3-d, 4-a

Answer

1-a, 2-b, 3-d, 4-c

Question 3

A 60-year-old patient presents with unilateral vesicular lesions in a dermatomal distribution on the torso. The lesions are painful and appeared over the past 2-3 days, progressing from erythematous patches to fluid-filled vesicles. The patient reports prodromal burning and tingling sensation in the affected area. Which of the following is the most likely diagnosis?

Accepted Answer

Herpes zoster infection

Answer

Irritant contact dermatitis

Answer

Allergic contact dermatitis

Answer

Herpes Simplex Infection

Question 4

Antigen presented on MHC class I molecules activates which of the following cells?

Accepted Answer

Cytotoxic T cells

Answer

NK cells

Answer

Helper cells

Answer

B cells

Question 5

Which of the following is true about anti-CMV IgG antibodies?

Accepted Answer

IgG avidity assay helps in differentiating past and primary infection

Answer

Denotes latent CMV infection

Answer

Denotes chronic CMV infection with immunity to other serotypes

Answer

Indicates acute CMV infection

Question 6

Which of the following statements regarding the given image is correct?

Accepted Answer

Majority of infections are asymptomatic in humans

Answer

Albendazole is the drug of choice

Answer

Infection is acquired by ingestion of undercooked freshwater fish

Answer

It is the largest tapeworm infecting humans

Question 7

Which of the following are acid-fast staining organisms?

1. Nocardia
2. Mycobacterium leprae
3. Actinomyces
4. Cryptosporidium parvum
5. Isospora belli

Accepted Answer

1,2,4,5

Answer

1,2,3

Answer

1,2,3,4,5

Answer

3,4,5

Question 8

An HIV patient came to the clinic with a history of diarrhea. Stool microscopy showed the oocysts that were 4-8 µm in size. The image is shown below. Identify the organism.

Accepted Answer

Cryptosporidium

Answer

Microsporidium

Answer

Cyclospora

Answer

Isospora

Question 9

The image below shows the life cycle of a virus. Which of the proteins of the virus act as oncogenes?

Accepted Answer

E6, E7

Answer

L1, L2

Answer

E1, E2, E5

Answer

E1, E2

Question 10

What is the ratio of T cells to B cells in a healthy adult?

Accepted Answer

3:1

Answer

1:3

Answer

1:1

Answer

1:2

INI-CET 2022

Dermatology

Microbiology

Pathology

Physiology