Infectious Diseases Practice Questions

Q: Rose spot is associated with

Typhoid fever. ***Typhoid fever*** - **Rose spots** are a characteristic rash of **typhoid fever** [1], appearing as transient, salmon-colored, maculopapular lesions, usually on the trunk and chest. - They are caused by bacterial emboli in the dermal capillaries, appearing in about 30% of patients during the first week of infection. *Scarlet fever* - Characterized by a **blanching erythematous rash** with a sandpaper-like texture (scarlatiniform rash), often starting on the neck and chest and spreading to the trunk and extremities. - This rash is typically due to the release of **erythrogenic toxins** by *Streptococcus pyogenes*. *Malaria* - While malaria can cause skin manifestations such as **jaundice**, petechiae, or urticaria, classical rose spots are **not a feature** of malaria [1]. - Its symptoms often include cycles of fever, chills, and sweats, rather than specific rashes. *Wilson disease* - This is a genetic disorder of **copper metabolism** and does not typically present with skin rashes like rose spots. - Manifestations include Kayser-Fleischer rings in the eyes, liver disease, and neurological symptoms.

Q: Most common site of gastrointestinal TB:

Terminal ileum. ***Terminal ileum*** - The **terminal ileum** is the most common site for gastrointestinal tuberculosis due to its rich lymphatic tissue (Peyer's patches) and slower transit time, allowing for increased contact time with the bacteria. - The organism, *Mycobacterium tuberculosis*, usually enters via ingested contaminated sputum or dairy products and predominantly affects the ileocecal region. *Colon* - While the colon can be affected by gastrointestinal TB, it is less common than the terminal ileum. - Colonic involvement often presents with symptoms mimicking **inflammatory bowel disease** or **carcinoma**. *Stomach* - Gastric involvement in TB is rare due to the highly acidic environment of the stomach, which is not conducive to bacterial survival. - When it does occur, it may present as **gastric ulcers** or hypertrophic lesions. *Duodenum* - Duodenal involvement in TB is also uncommon; the rapid transit of food and the less prominent lymphoid tissue in this region make it a less favorable site for infection. - Symptoms, if present, can include **obstruction** or **ulceration**.

Q: A lesion was seen on the face of a 42 year old patient as shown below. Which of the following would be ideal management for this condition?

Start on ATT. ***Start on ATT*** - The presented image shows a **gummy lesion** on the face, which is characteristic of **tuberculosis cutis colliquativa**, a form of cutaneous tuberculosis. - **Anti-tubercular therapy (ATT)** is the primary and most effective treatment for all forms of tuberculosis, including cutaneous manifestations. *Topical retinoids* - Topical retinoids are primarily used for **acne vulgaris** and certain **disorders of keratinization** and are not indicated for infectious granulomatous conditions. - They work by **regulating cell growth and differentiation**, which is not the mechanism required to treat tuberculosis. *Oral steroids* - Oral steroids are **immunosuppressive** and generally contraindicated in active infections like tuberculosis, as they can worsen the disease. - While they might be used short-term in some inflammatory skin conditions, they would **not address the underlying tuberculous infection**. *Start on MDT for leprosy* - **Multi-drug therapy (MDT)** is the standard treatment for leprosy, which also presents with skin lesions and nerve involvement. - However, the image shows a **single, nodular, ulcerated lesion** more typical of cutaneous tuberculosis rather than the varied forms of leprosy (macular, papular, nodular lesions, or nerve thickening).

Q: HIV patient presented with diarrhea. On stool examination, acid-fast organisms (Isospora belli) were seen. What is the drug of choice in this patient?

TMP-SMX. ***TMP-SMX*** - **Trimethoprim-sulfamethoxazole (TMP-SMX)** is the primary treatment for **Isospora belli** infections, especially in HIV-positive patients [1]. - It is highly effective in eradicating the parasite and preventing relapses in immunocompromised individuals [1]. *Niclosamide* - **Niclosamide** is an antihelminthic drug primarily used for treating **tapeworm infections** [2]. - It is not effective against protozoal parasites like *Isospora belli*. *Nitazoxanide* - **Nitazoxanide** is an antiparasitic drug that can be used for various protozoal and helminthic infections, including *Cryptosporidium* and *Giardia*. - While it has some efficacy against *Isospora belli*, it is generally considered a second-line agent, with **TMP-SMX** being the drug of choice [1]. *Primaquine* - **Primaquine** is an antimalarial drug specifically used to prevent relapse of **Plasmodium vivax** and **Plasmodium ovale** malaria by targeting hypnozoites. - It has no role in the treatment of **Isospora belli** infection.

Q: After a renal transplant, what is the most common opportunistic infection?

Cytomegalovirus (CMV). ***Cytomegalovirus (CMV)*** - **CMV** is the most common opportunistic infection after renal transplantation, particularly in the first 6 months due to immunosuppression [1]. - It can cause a range of clinical syndromes, including **fever**, **leukopenia**, **gastroenteritis**, **pneumonitis**, and **hepatitis**, and can also have indirect effects that increase the risk of graft rejection. *Varicella Zoster Virus (VZV)* - While VZV can cause opportunistic infections in transplant recipients (e.g., **shingles**), it is less common than CMV [1]. - VZV typically occurs later post-transplant and is characterized by a **vesicular rash** in a dermatomal distribution. *Coxsackie Virus* - **Coxsackie virus** infections are less frequently reported as significant opportunistic infections in renal transplant recipients compared to other viral pathogens. - They are generally associated with hand-foot-and-mouth disease, herpangina, or myocarditis, which are not the most common post-transplant complications. *Epstein-Barr Virus (EBV)* - **EBV** can cause post-transplant lymphoproliferative disorder (PTLD), which is a serious complication, but EBV infection itself is not the most common opportunistic infection overall [1]. - PTLD is more common in the first year after transplant and often presents with **lymphadenopathy**, **fever**, or **graft dysfunction**.

Q: Which of the following is not an AIDS defining illness?

Hodgkin's lymphoma. ***Hodgkin's lymphoma*** - While patients with HIV are at an increased risk of developing **Hodgkin's lymphoma**, it is not officially classified as an **AIDS-defining illness** by the CDC [3]. - AIDS-defining conditions primarily include certain opportunistic infections and specific malignancies [4]. *Cervical cancer* - **Invasive cervical cancer** is an AIDS-defining illness in HIV-positive women, indicating severe immunosuppression [4]. - This is because HIV infection can accelerate or worsen the progression of **HPV-related cervical dysplasia** to invasive cancer [4]. *Primary CNS lymphoma* - **Primary CNS lymphoma** (brain lymphoma) is an AIDS-defining illness, particularly when associated with **Epstein-Barr virus** [2]. - Its presence indicates a significant degree of **immunodeficiency** in HIV-infected individuals. *Kaposi sarcoma* - **Kaposi sarcoma** is a well-known and common AIDS-defining malignancy, caused by **Human Herpesvirus 8 (HHV-8)** [1]. - It presents as vascular lesions on the skin, mucous membranes, internal organs, and lymph nodes [1].

Q: Not an AIDS defining illness?

Tertiary Syphilis. ***Tertiary Syphilis*** - While a serious late-stage manifestation of **syphilis**, it is not specifically listed as an **AIDS-defining illness** by the CDC, although HIV-positive individuals may be more susceptible to its complications [1]. - **Neurosyphilis**, a form of tertiary syphilis affecting the central nervous system, is also not an AIDS-defining condition on its own, unlike some other opportunistic infections [1]. *Progressive multifocal leukoencephalopathy (PML)* - PML, caused by the **JC virus**, is an **AIDS-defining illness** characterized by the progressive destruction of myelin in the brain, leading to severe neurological deficits. - It occurs almost exclusively in individuals with severe **immunodeficiency**, such as those with untreated HIV infection. *Lymphoma of brain < 60 years of age* - **Primary central nervous system (CNS) lymphoma** in individuals with HIV, especially those under 60 years of age, is an **AIDS-defining condition** [2]. - Its occurrence is strongly linked to severe immunosuppression in HIV-infected patients [2]. *Extrapulmonary Cryptococcosis* - **Cryptococcosis**, when it affects sites outside the lungs (e.g., **cryptococcal meningitis**), is an **AIDS-defining illness**. - This fungal infection is a common opportunistic infection in individuals with advanced HIV disease.

Q: Mean transformation time for HIV to AIDS is:-

10 years. ***10 years*** - The mean transformation time from initial **HIV infection** to the development of **AIDS** in untreated individuals is approximately 10 years [1]. - This time frame represents the average duration of the **clinical latency period**, during which the viral load increases and CD4+ T-cell count gradually declines [1]. *12 years* - While some individuals may progress to AIDS later than 10 years, 12 years is not recognized as the **mean transformation time**. - This longer period might be seen in individuals with slower disease progression or those initiating **antiretroviral therapy (ART)** at later stages. *9 years* - This duration is slightly shorter than the generally accepted mean, though some individuals may progress more rapidly. - Factors like **higher viral load** at infection, coinfections, or certain genetic predispositions can accelerate progression. *5 years* - A transformation time of 5 years is considered a **rapid progression** to AIDS. - This rapid progression is typically seen in a minority of HIV-infected individuals, often associated with factors such as high baseline viral load, genetic susceptibility, or co-infection with other pathogens.

Q: Match the following CSF findings with the most likely stage of syphilis: A. Normal CSF B. High protein, moderate pleocytosis C. High protein, high pleocytosis D. Normal protein, mild pleocytosis 1. Meningovascular syphilis 2. Primary syphilis 3. Tabes dorsalis 4. Meningeal syphilis

A-2, B-4, C-1, D-3. ***A-2, B-4, C-1, D-3*** - **Primary syphilis** (2) typically involves no direct central nervous system involvement, hence **normal CSF** (A) is expected. - **Meningeal syphilis** (4) is an early neurological manifestation characterized by inflammation of the meninges, leading to a **high protein** level and **moderate pleocytosis** (B). - **Meningovascular syphilis** (1) involves inflammation of blood vessels in the brain and is associated with significant inflammation, reflected by **high protein** and **high pleocytosis** (C). - **Tabes dorsalis** (3) is a late manifestation affecting the spinal cord's posterior columns, often presenting with **normal protein** and **mild pleocytosis** (D) due to chronic, less acute inflammation. *A-2, B-1, C-4, D-3* - This option incorrectly associates **meningovascular syphilis** with moderate pleocytosis and **meningeal syphilis** with high pleocytosis, which is not typical. - Meningovascular syphilis generally presents with more pronounced CSF abnormalities (higher pleocytosis) compared to meningeal syphilis. *A-2, B-3, C-4, D-1* - This option incorrectly links **tabes dorsalis** with high protein and moderate pleocytosis, and **meningeal syphilis** with high protein and high pleocytosis. - Tabes dorsalis usually has milder CSF changes, while meningeal syphilis is typically moderate rather than high pleocytosis. *A-2, B-3, C-1, D-4* - This option incorrectly associates **tabes dorsalis** with high protein and moderate pleocytosis, and **meningeal syphilis** with normal protein and mild pleocytosis. - The CSF findings for tabes dorsalis are generally milder, and meningeal syphilis involves more significant inflammation.

Question 1

Rose spot is associated with

Accepted Answer

Typhoid fever

Answer

Scarlet fever

Answer

Malaria

Answer

Wilson disease

Question 2

True about diphtheria is -

Accepted Answer

Erythromycin is an alternative antibiotic for penicillin-allergic patients

Answer

Passive immunization is harmful and should not be tried

Answer

Cause cranial nerve palsies in 2nd & 3rd week

Answer

It is gram negative organism

Question 3

Most common site of gastrointestinal TB:

Accepted Answer

Terminal ileum

Answer

Colon

Answer

Stomach

Answer

Duodenum

Question 4

A lesion was seen on the face of a 42 year old patient as shown below. Which of the following would be ideal management for this condition?

Accepted Answer

Start on ATT

Answer

Topical retinoids

Answer

Oral steroids

Answer

Start on MDT for leprosy

Question 5

HIV patient presented with diarrhea. On stool examination, acid-fast organisms (Isospora belli) were seen. What is the drug of choice in this patient?

Accepted Answer

TMP-SMX

Answer

Niclosamide

Answer

Nitazoxanide

Answer

Primaquine

Question 6

After a renal transplant, what is the most common opportunistic infection?

Accepted Answer

Cytomegalovirus (CMV)

Answer

Varicella Zoster Virus (VZV)

Answer

Coxsackie Virus

Answer

Epstein-Barr Virus (EBV)

Question 7

Which of the following is not an AIDS defining illness?

Accepted Answer

Hodgkin's lymphoma

Answer

Cervical cancer

Answer

Primary CNS lymphoma

Answer

Kaposi sarcoma

Question 8

Not an AIDS defining illness?

Accepted Answer

Tertiary Syphilis

Answer

Progressive multifocal leukoencephalopathy

Answer

Lymphoma of brain < 60 years of age

Answer

Extrapulmonary Cryptococcosis

Question 9

Mean transformation time for HIV to AIDS is:-

Accepted Answer

10 years

Answer

12 years

Answer

9 years

Answer

5 years

Question 10

Match the following CSF findings with the most likely stage of syphilis:
A. Normal CSF
B. High protein, moderate pleocytosis
C. High protein, high pleocytosis
D. Normal protein, mild pleocytosis

1. Meningovascular syphilis
2. Primary syphilis
3. Tabes dorsalis
4. Meningeal syphilis

Accepted Answer

A-2, B-4, C-1, D-3

Answer

A-2, B-1, C-4, D-3

Answer

A-2, B-3, C-4, D-1

Answer

A-2, B-3, C-1, D-4

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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