Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 1141: A complicated urinary tract infection (UTI) is defined as an infection that fails to resolve or recurs within how much time of standard therapy?

A. 1 week
B. 2 weeks (Correct Answer)
C. 3 weeks
D. 4 weeks

Explanation: **2 weeks** - A complicated urinary tract infection (UTI) is defined by its failure to resolve or recurrence within **two weeks** of completing standard antimicrobial therapy [1]. - This time frame is crucial for identifying UTIs that may be associated with **structural or functional abnormalities** of the urinary tract [1]. *1 week* - While recurrence within one week is certainly concerning, the standard definition for a complicated UTI due to treatment failure or recurrence extends to the two-week mark. - Assessing treatment efficacy over one week might be too short to definitively label a UTI as complicated in all cases. *3 weeks* - If a UTI recurs after three weeks, it is often considered a **reinfection** rather than a failure of the initial treatment or an indicator of a complicated UTI from the original episode [1]. - The focus for defining complicated UTI is typically on earlier recurrence or failure to achieve cure within a shorter, defined period. *4 weeks* - Recurrence after four weeks is generally considered a new infection or reinfection, rather than a failure of the initial therapy for a complicated UTI [1]. - The timeframe for classifying a UTI as complicated due to inadequate initial treatment response is specifically within weeks, not months.

Question 1142: Which of the following organisms is not typically associated with causing chronic adrenal insufficiency?

A. Histoplasma capsulatum
B. Coccidioides immitis
C. Mycobacterium bovis (Correct Answer)
D. Mycobacterium tuberculosis

Explanation: ***Mycobacterium bovis*** - While *Mycobacterium bovis* can cause tuberculosis-like disease, it is **less commonly associated with chronic adrenal insufficiency** compared to *M. tuberculosis* itself, which has a predilection for adrenal tissue. - Infection with *M. bovis* primarily affects cattle and can be transmitted to humans, but its tropism for the adrenal glands leading to insufficiency is not a primary recognized feature. *Mycobacterium tuberculosis* - **Tuberculosis** is a well-known cause of chronic adrenal insufficiency, also known as **Addison's disease**, particularly in endemic regions. [1] - The bacteria can directly infect and destroy the adrenal cortex, leading to impaired hormonal production. *Histoplasma capsulatum* - **Disseminated histoplasmosis**, especially in immunocompromised individuals, can directly involve the adrenal glands. - This fungal infection can lead to **adrenal destruction and chronic adrenal insufficiency** by granuloma formation and necrosis. *Coccidioides immitis* - **Disseminated coccidioidomycosis** is another fungal infection that can cause adrenal gland involvement. - Similar to histoplasmosis, it can lead to **granulomatous inflammation and necrosis** within the adrenal cortex, resulting in chronic adrenal insufficiency.

Question 1143: Which of the following is NOT a characteristic of Dengue shock syndrome?

A. Pleural effusion
B. Thrombocytopenia
C. Decreased haemoglobin (Correct Answer)
D. Hepatomegaly

Explanation: ***Decreased haemoglobin*** - **Decreased hemoglobin** is *not* a characteristic feature of Dengue shock syndrome; rather, **hemoconcentration**, indicated by an *increased* hematocrit, is a hallmark due to plasma leakage. - While bleeding can occur in dengue, leading to decreased hemoglobin, **hemoconcentration** is a more direct and consistent sign of severe plasma leakage in Dengue Shock Syndrome [1]. *Hepatomegaly* - **Hepatomegaly** (enlarged liver) is a common finding in severe dengue, including Dengue Shock Syndrome, due to hepatic inflammation and dysfunction [1]. - This symptom reflects the systemic nature of the infection and can contribute to abdominal pain and tenderness. *Pleural effusion* - **Pleural effusion** is a key indicator of **plasma leakage**, a defining characteristic of severe dengue and Dengue Shock Syndrome [1]. - The effusion results from fluid transudation into the pleural space, often accompanied by ascites. *Thrombocytopenia* - **Thrombocytopenia** (low platelet count) is a consistent and serious finding in dengue, particularly in severe forms like Dengue Shock Syndrome [1]. - A significant drop in platelet count often precedes or accompanies the onset of shock and increases the risk of bleeding.

Question 1144: Which of the following is a known risk factor for cholangiocarcinoma?

A. Giardia lamblia (intestinal protozoa) infection
B. Ascaris lumbricoides (roundworm) infection
C. Clonorchis sinensis infestation (Correct Answer)
D. Paragonimus westermani infestation

Explanation: ***Clonorchis sinensis infestation*** - **Clonorchis sinensis**, also known as the Chinese liver fluke, is a well-established and significant risk factor for the development of **cholangiocarcinoma**. - Chronic inflammation and irritation of the bile ducts caused by the parasite are believed to promote malignant transformation. *Giardia lamblia (intestinal protozoa) infection* - **Giardia lamblia** is a common intestinal parasite causing giardiasis, characterized by diarrhea and malabsorption. - While it affects the gastrointestinal tract, there is **no known association** between *Giardia* infection and an increased risk of cholangiocarcinoma. *Paragonimus westermani infestation* - **Paragonimus westermani** is a lung fluke that primarily causes paragonimiasis, affecting the lungs and leading to cough and hemoptysis. - This parasite is not associated with direct bile duct inflammation or an increased risk of **cholangiocarcinoma**. *Ascaris lumbricoides (roundworm) infection* - **Ascaris lumbricoides** is a large intestinal roundworm that can cause intestinal obstruction or nutrient deficiencies. - Although it can occasionally migrate into the biliary tree, it is **not considered a risk factor** for cholangiocarcinoma [1].

Question 1145: Bloody diarrhea in HIV infected patient is mostly due to ?

A. Cryptosporidium
B. Isospora
C. CMV (Correct Answer)
D. Salmonella

Explanation: ***CMV*** - **Cytomegalovirus (CMV) colitis** is a common opportunistic infection in advanced HIV, causing **bloody diarrhea**, abdominal pain, and fever. - CMV infection can lead to **ulcerations** and inflammation of the colonic mucosa, resulting in blood in the stool. *Cryptosporidium* - **Cryptosporidiosis** causes profuse, **watery diarrhea** in HIV patients, not typically bloody [1]. - While it can be severe and persistent, it primarily affects the small intestine, leading to malabsorption. *Isospora* - **Isosporiasis** (caused by *Isospora belli*) primarily presents as **unrelenting watery diarrhea** in immunocompromised individuals [1]. - It affects the small bowel and does not commonly result in bloody stools. *Salmonella* - **Salmonella gastroenteritis** can cause bloody diarrhea, but in HIV patients, it is often associated with **bacteremia** and systemic infection. - While possible, **CMV colitis** is a more classic and frequent cause of bloody diarrhea in advanced HIV in the absence of other focal symptoms.

Question 1146: Which hepatitis infection is most commonly associated with immune thrombocytopenic purpura?

A. Hepatitis A infection
B. Hepatitis B infection
C. Hepatitis C infection (Correct Answer)
D. Hepatitis D infection

Explanation: ***Hepatitis C infection*** - **Hepatitis C** is well-established for causing various **extrahepatic manifestations**, including mixed cryoglobulinemia, membranoproliferative glomerulonephritis, and **immune thrombocytopenic purpura (ITP)**. - The mechanism involves chronic viral stimulation leading to the production of **autoantibodies** against platelets and megakaryocytes, or direct viral effects on bone marrow. *Hepatitis A infection* - **Hepatitis A** is an **acute, self-limiting viral infection** [1] that typically does not lead to chronic liver disease or significant extrahepatic manifestations like ITP. - There are rare reports of transient thrombocytopenia in acute hepatitis A, but it is not commonly associated with chronic ITP. *Hepatitis B infection* - While **Hepatitis B** can cause extrahepatic manifestations such as polyarteritis nodosa and glomerulonephritis, its association with **immune thrombocytopenic purpura (ITP)** is less frequent and not as strong as with Hepatitis C. - HBV-associated thrombocytopenia is more often related to **hypersplenism** in cirrhotics or direct viral bone marrow suppression, rather than immune-mediated destruction. *Hepatitis D infection* - **Hepatitis D (HDV)** is a **defective virus** that requires co-infection with Hepatitis B virus (HBV) to replicate. - Its extrahepatic manifestations are primarily linked to the underlying **HBV infection**, and there is no strong, independent association with immune thrombocytopenic purpura.

Question 1147: Pulmonary eosinophilia is found in infection with ?

A. Babesia
B. Malaria
C. Strongyloides (Correct Answer)
D. Trypanosoma

Explanation: ***Strongyloides*** - **Strongyloides stercoralis** can cause **pulmonary eosinophilia** (Löffler's syndrome) as larvae migrate through the lungs [1]. - This migration is part of the parasite's life cycle, leading to an inflammatory response with eosinophil infiltration [1]. *Babesia* - **Babesia** species primarily infect **red blood cells** and cause **hemolytic anemia**, resembling malaria. - They are transmitted by ticks and do not typically cause pulmonary eosinophilia. *Malaria* - **Malaria**, caused by Plasmodium parasites, is known for infecting **red blood cells** and causing cyclical fevers, chills, and anemia. - It does not typically present with pulmonary eosinophilia as a characteristic feature. *Trypanosoma* - **Trypanosoma** species cause **sleeping sickness** (African trypanosomiasis) and **Chagas disease** (American trypanosomiasis). - These infections affect the bloodstream, lymphatic system, and various organs, but pulmonary eosinophilia is not a hallmark.

Question 1148: A 60-year-old farmer presents with swelling on the sole of the foot accompanied by discharging yellow granules. What is the most likely diagnosis?

A. Fungal mycetoma
B. Actinomycosis (Correct Answer)
C. Candidiasis
D. Actinomycetoma

Explanation: ***Actinomycosis*** - The presentation of a **slowly progressive swelling** with **draining sinuses** that exude **"sulfur granules" (yellow granules)** is highly characteristic of actinomycosis. - While often associated with the cervicofacial region, actinomycosis can affect other sites such as the foot, especially after **trauma** or through direct inoculation from soil, consistent with a farmer's occupation. *Fungal mycetoma* - While fungal mycetoma also presents with **swelling, draining sinuses**, and **granules**, these granules are typically **black or white** from fungal elements, not yellow [1]. - The causative agents are true fungi, and the clinical course might differ subtly, but the **color of the granules** is a key differentiator [1]. *Actinomycetoma* - Actinomycetoma is caused by **filamentous bacteria** (like *Nocardia* or *Actinomadura*), which are a type of bacterial mycetoma. It presents similarly to fungal mycetoma with **granules**, but these are usually **white, red, or yellow-brown**, and less commonly the bright yellow "sulfur granules" seen in classical actinomycosis. - It’s important to distinguish actinomycetoma (bacterial mycetoma) from actinomycosis, which is caused by *Actinomyces* species and is characterized specifically by the classic sulfur granules. *Candidiasis* - **Candidiasis** (yeast infection) typically presents as **mucocutaneous lesions, thrush, or invasive systemic infections**, not localized swelling with discharging yellow granules on the sole of the foot. - It does not involve the formation of granules or sinuses in this manner.

Question 1149: Which of the following is an ocular complication associated with Zika virus infection?

A. Liver inflammation
B. Heart inflammation
C. Eye inflammation (Correct Answer)
D. None of the options

Explanation: ***Eye inflammation*** - **Ocular manifestations** are recognized complications of **Zika virus infection**, ranging from conjunctivitis to more severe conditions like **uveitis** and **optic neuritis**. - Specifically, **chorioretinal scars** and **optic nerve abnormalities** have been observed in infants with congenital Zika syndrome. *Liver inflammation* - **Hepatitis**, or liver inflammation, is not a common or specific complication directly associated with Zika virus infection. - While some viral infections can affect the liver, **Zika** primarily targets **neural tissues** and has specific ocular and neurological complications. *Heart inflammation* - **Myocarditis**, or heart inflammation, is not a frequently reported or characteristic complication of **Zika virus infection**. - The primary systemic manifestations of **Zika** typically involve **mild fever**, **rash**, **arthralgia**, and **conjunctivitis**, with severe outcomes usually being neurological. *None of the options* - This option is incorrect because **eye inflammation** is a well-documented and significant ocular complication of **Zika virus infection**. - The virus is known to have **tropism for ocular tissues**, leading to various visual impairments.

Question 1150: CCR5 mutation is related to which condition ?

A. Resistance to HIV infection (Correct Answer)
B. Susceptibility to HIV infection
C. Resistance to HBV infection
D. Susceptibility to HBV infection

Explanation: ***Resistance to HIV infection*** - A specific mutation, **CCR5-delta32**, leads to a non-functional **CCR5 receptor** on the surface of immune cells. - Since **HIV** primarily uses the **CCR5 receptor** to enter target cells, individuals with this mutation are highly resistant to HIV infection. *Susceptibility to HIV infection* - A functional **CCR5 receptor** is required for most **HIV** strains (R5 strains) to enter human cells. - Mutations leading to a non-functional **CCR5 receptor** decrease, rather than increase, susceptibility to HIV. *Resistance to HBV infection* - The **hepatitis B virus (HBV)** uses different cellular receptors for entry, primarily the **sodium taurocholate co-transporting polypeptide (NTCP)**. - **CCR5** mutations have no known effect on susceptibility or resistance to **HBV infection**. *Susceptibility to HBV infection* - Susceptibility to **HBV** infection is determined by the presence and functionality of its specific entry receptors, such as NTCP. - **CCR5** mutations do not impact these pathways and therefore do not influence susceptibility to **HBV**.

Practice by Chapter

Principles of Antimicrobial Therapy

Practice Questions

Fever of Unknown Origin

Practice Questions

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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