Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 1001: Which of the following is the most commonly reported nutritional consequence of heavy Ascaris lumbricoides infection?

A. Folic Acid
B. Vitamin A
C. Iron
D. Vitamin B12 (Correct Answer)

Explanation: ***Vitamin B12*** - **Ascaris lumbricoides** infection, particularly heavy infestation, can lead to malabsorption of **Vitamin B12**. [1] - This occurs as the parasites consume the vitamin or interfere with its absorption in the small intestine, potentially leading to **megaloblastic anemia**. [1], [2] *Folic Acid* - While malabsorption can occur in severe parasitic infections, **folic acid deficiency** is less commonly reported as the primary nutritional consequence of Ascaris compared to B12. [2] - Deficiency usually manifests as another form of **megaloblastic anemia**, often seen in conditions like celiac disease or alcoholism. *Vitamin A* - **Vitamin A deficiency** can be exacerbated by chronic infections, including parasitic ones, due to impaired absorption or increased metabolic demand. - However, it's not the most commonly cited specific nutritional consequence of Ascaris infection in many epidemiological studies directly linking the two. *Iron* - **Iron deficiency anemia** is common in many parasitic infections, particularly those causing blood loss like hookworm infections. - While Ascaris can contribute to general poor nutrition, it is not primarily associated with direct iron loss or malabsorption to the same extent as other parasites.

Question 1002: After a renal transplant, what is the most common opportunistic infection?

A. Varicella Zoster Virus (VZV)
B. Coxsackie Virus
C. Epstein-Barr Virus (EBV)
D. Cytomegalovirus (CMV) (Correct Answer)

Explanation: ***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**.

Question 1003: Which of the following is not an AIDS defining illness?

A. Cervical cancer
B. Hodgkin's lymphoma (Correct Answer)
C. Primary CNS lymphoma
D. Kaposi sarcoma

Explanation: ***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].

Question 1004: Not an AIDS defining illness?

A. Progressive multifocal leukoencephalopathy
B. Lymphoma of brain < 60 years of age
C. Extrapulmonary Cryptococcosis
D. Tertiary Syphilis (Correct Answer)

Explanation: ***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.

Question 1005: Which of the following is true about polyaeritis nodosa?

A. It shows fibrinoid necrosis in large blood vessels
B. HBsAg is positive in 30% patients (Correct Answer)
C. It has ANCA positivity
D. Affected individuals have involvement of pulmonary circulation.

Explanation: ### HBsAg is positive in 30% patients - **Polyarteritis nodosa (PAN)** is strongly associated with **hepatitis B virus (HBV)** infection; about 30% of patients with PAN have evidence of current or past HBV infection, particularly **HBsAg positivity**. - This association suggests that HBV infection can trigger the immune complex vasculitis characteristic of PAN. ### It shows fibrinoid necrosis in large blood vessels - PAN primarily affects **medium-sized muscular arteries**, not typically large blood vessels [1]. - The inflammation causes **fibrinoid necrosis** and aneurysmal dilations in these medium-sized arteries [1]. ### It has ANCA positivity - **Polyarteritis nodosa (PAN)** is generally considered an **ANCA-negative vasculitis**. - **ANCA positivity** (especially c-ANCA/PR3-ANCA or p-ANCA/MPO-ANCA) is characteristic of other small-vessel vasculitides like **Granulomatosis with polyangiitis** or **Microscopic polyangiitis**. ### Affected individuals have involvement of pulmonary circulation. - A defining characteristic of **Polyarteritis nodosa (PAN)** is that it generally **spares the pulmonary circulation** [1]. - Pulmonary involvement is more commonly seen in other vasculitides, such as **Granulomatosis with polyangiitis (Wegener's)** or **Eosinophilic granulomatosis with polyangiitis (Churg-Strauss)**.

Question 1006: Mean transformation time for HIV to AIDS is:-

A. 12 years
B. 9 years
C. 5 years
D. 10 years (Correct Answer)

Explanation: ***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.

Question 1007: 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. A-2, B-4, C-1, D-3 (Correct Answer)
B. A-2, B-1, C-4, D-3
C. A-2, B-3, C-4, D-1
D. A-2, B-3, C-1, D-4

Explanation: ***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 1008: Asymptomatic HIV-positive patient has RPR 1:128, TPHA positive. No symptoms or signs. Previous syphilis treatment 2 years ago with documented 4-fold decline in titers. Most appropriate next step is:

A. Repeat RPR in 3 months
B. Treat as reinfection
C. CSF examination (Correct Answer)
D. Treat as late latent syphilis

Explanation: ***CSF examination*** - In an HIV-positive patient with a **high RPR titer (1:128)** and a history of previous syphilis treatment, **neurosyphilis** must be ruled out, even without neurological symptoms. This is because **HIV can alter the natural history of syphilis**, increasing the risk of neurological involvement. - A **CSF examination** is crucial to look for signs of neurosyphilis, such as elevated white blood cell count, elevated protein, or a reactive VDRL, which would necessitate different and more aggressive treatment. *Repeat RPR in 3 months* - While monitoring RPR titers is important, a high titer of 1:128 in an HIV-positive patient is concerning enough to warrant immediate investigation rather than just observation [1]. Waiting 3 months could delay diagnosis and treatment of potential neurosyphilis. - This option is more appropriate if the patient had a **declining or stable low titer** and no prior history of high titers or if the clinical concern for active infection was lower. *Treat as reinfection* - While a high RPR titer *can* indicate reinfection, the most appropriate first step in an HIV-positive patient with a high titer and a history of prior treatment is to rule out **neurosyphilis** before automatically treating for uncomplicated reinfection. - Treating for reinfection without CSF evaluation could miss or delay the appropriate treatment for neurosyphilis, which requires a longer course of intravenous antibiotics. *Treat as late latent syphilis* - Late latent syphilis is typically characterized by **asymptomatic infection** of more than one year duration or unknown duration, with a reactive serology but no clinical signs [1]. However, the presence of **HIV** and a **very high RPR titer** changes the diagnostic approach significantly. - Treating for late latent syphilis without ruling out neurosyphilis would be inadequate if neurological involvement is present, as the treatment regimens differ.

Question 1009: Assertion: HIV-positive patients with syphilis should receive the same treatment as HIV-negative patients. Reason: Serological response to treatment is similar in both groups.

A. Both A and R are false
B. Both A and R are true, R explains A
C. Both A and R are true, R doesn't explain A
D. A is true but R is false (Correct Answer)

Explanation: **_A is true but R is false_** * **HIV-positive patients with syphilis** often have altered immune responses, leading to atypical presentations and a higher risk of **neurological complications** and treatment failure. Therefore, treatment regimens often need to be modified, such as extending the duration of therapy or using higher doses, especially for early syphilis in HIV-positive patients. * **Serological response** in HIV-positive individuals is often **less predictable** and may be slower or show less robust decline in antibody titers compared to HIV-negative individuals, making routine follow-up testing crucial. * The assertion that serological response is similar in both groups is **false** because HIV can affect the immune response to syphilis, potentially blunting the serological response to treatment and making interpretation more challenging.

Question 1010: A nurse got accidental prick from the HIV infected needle. Which of the following statements is false regarding the management of this nurse?

A. Follow up viral markers of health care personnel should be measured at 6 weeks
B. Zidovudine is used as monotherapy for post-exposure prophylaxis (Correct Answer)
C. Baseline viral markers of health care personnel should be done at the time of presentation
D. Washing hands with soap and water is advised

Explanation: **Zidovudine is used as monotherapy for post-exposure prophylaxis** - **Monotherapy** with zidovudine is **insufficient** for effective **HIV post-exposure prophylaxis (PEP)** due to the high risk of treatment failure and development of drug resistance. - **Current guidelines** recommend a **multi-drug regimen**, typically involving three antiretroviral drugs, for PEP to maximize efficacy against HIV transmission. *Follow up viral markers of health care personnel should be measured at 6 weeks* - **Follow-up viral markers** for HIV, such as **HIV RNA PCR** and **antibody tests**, are routinely measured at specific intervals (e.g., 6 weeks, 3 months, 6 months) to monitor for seroconversion [1]. - This allows for **early detection of HIV infection** if PEP fails, enabling prompt initiation of treatment. *Baseline viral markers of health care personnel should be done at the time of presentation* - Establishing **baseline HIV status** of the healthcare worker at the time of exposure is crucial to differentiate pre-existing infection from a new infection acquired from the needle stick [1]. - This information helps in **interpreting subsequent test results** and guiding further management. *Washing hands with soap and water is advised* - **Immediate washing** of the exposed area with **soap and water** is an important first step in managing a needle stick injury [1]. - This **reduces the viral load** at the site of exposure, minimizing the risk of transmission, although it does not eliminate the need for PEP.

Practice by Chapter

Principles of Antimicrobial Therapy

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Fever of Unknown Origin

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HIV/AIDS and Related Infections

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Tuberculosis and Mycobacterial Diseases

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Tropical and Parasitic Infections

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Viral Infections (Hepatitis, Herpes, etc.)

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Healthcare-Associated Infections

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Fungal Infections

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Sepsis and Septic Shock

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Infection in Immunocompromised Hosts

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Emerging and Re-emerging Infections

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Antimicrobial Resistance

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Vaccination Principles

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