Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 1151: Non-parasitic eosinophilia is caused by infection with -

A. Coccidioidomycosis (Valley Fever) (Correct Answer)
B. Ehrlichiosis
C. Candidiasis (Yeast infection)
D. Staphylococcal infection

Explanation: ***Coccidioidomycosis (Valley Fever)*** - **Coccidioidomycosis** is a systemic fungal infection that characteristically causes **non-parasitic eosinophilia**. This is a classic association frequently tested. - The host immune response to this specific fungal pathogen often involves a significant increase in **eosinophil count**. *Ehrlichiosis* - **Ehrlichiosis** is a bacterial infection transmitted by ticks, which typically causes **leukopenia** (low white blood cell count), sometimes with relative lymphocytosis. - While it affects various blood cell lines, it does not characteristically lead to **eosinophilia**; rather, it's more associated with low platelet and white cell counts. *Candidiasis (Yeast infection)* - **Candidiasis** is a common fungal infection, but it almost never causes **eosinophilia** [1]. - Systemic candidiasis is more likely to cause **neutrophilia**, rather than an increase in eosinophils [1]. *Staphylococcal infection* - **Staphylococcal infections** are bacterial and typically cause **neutrophilia** as the primary response.

Question 1152: Which of the following characteristics does NOT apply to the rash of chickenpox when differentiating it from smallpox?

A. Not centripetal
B. Deep-seated (Correct Answer)
C. Monomorphic
D. Superficial

Explanation: ***Deep-seated*** - The rash of chickenpox is typically **superficial**, affecting the epidermis and upper dermis, leading to vesicles that are easily ruptured [1]. - In contrast, a **deep-seated** rash is characteristic of smallpox, where lesions extend into the deeper dermis, giving them a firm, "shotty" feel upon palpation. *Not centripetal* - This statement is generally true for chickenpox; its rash distribution tends to be **centrifugal**, meaning it is more concentrated on the trunk and extremities, sparing the face and distal limbs [1]. - Smallpox, however, is characterized by a **centripetal distribution**, with lesions most concentrated on the face and extremities. *Monomorphic* - This characteristic does NOT apply to chickenpox. Chickenpox exhibits a **pleomorphic rash**, meaning lesions at various stages of development (macules, papules, vesicles, scabs) are present simultaneously [1]. - A **monomorphic rash**, where all lesions are at the same stage of development, is a hallmark of smallpox. *Superficial* - This characteristic **applies** to chickenpox [1]. The lesions are typically superficial, affecting the epidermal layers and leading to a fragile, easily ruptured vesicle. - Smallpox lesions, in contrast, are **deep-seated**, firm, and umbilicated.

Question 1153: Major criteria for infective endocarditis include which of the following

A. History of injection drug use
B. Presence of Osler's nodes
C. Isolation of a typical organism from two separate blood cultures (Correct Answer)
D. Persistent fever for more than 4 days

Explanation: ***Isolation of a typical organism from two separate blood cultures*** - This is a definitive **major criterion** for infective endocarditis, indicating active bacterial infection in the bloodstream [1]. - The isolation of a **typical microorganism** (e.g., *S. aureus*, viridans streptococci) from multiple blood samples helps confirm the diagnosis [1]. *History of injection drug use* - While **injection drug use** is a significant **risk factor** for infective endocarditis, it is not a diagnostic major criterion itself [1]. - It increases the likelihood of infection but does not confirm the presence of endocarditis. *Presence of Osler's nodes* - **Osler's nodes** are painful, tender, red or purple lesions found on the hands and feet, which are considered **minor criteria** (immunological phenomena) for infective endocarditis [1]. - They are a clinical sign, but not as diagnostically definitive as microbiological evidence. *Persistent fever for more than 4 days* - **Fever** (temperature >38°C) is a common symptom and a **minor criterion** for infective endocarditis [1]. - However, the duration of fever alone is not a major criterion and can be indicative of many other conditions.

Question 1154: Most common mode of spread for genital tuberculosis is?

A. Hematogenous (Correct Answer)
B. Lymphatic
C. Direct
D. Ascending

Explanation: ***Hematogenous*** - **Genital tuberculosis** most commonly spreads via the bloodstream from a primary site of infection, typically the **lungs** [2]. - This mode of spread allows the **Mycobacterium tuberculosis** bacilli to reach diverse pelvic organs, establishing secondary foci [2]. *Lymphatic* - While lymphatic spread can occur in tuberculosis, it is less common for disseminating infection to the genital tract compared to the **hematogenous route** [1]. - Lymphatic spread often leads to regional lymph node involvement rather than widespread dissemination to reproductive organs [1]. *Direct* - **Direct spread** from an adjacent organ infected with tuberculosis is rare for genital involvement. - This mode would involve local extension, which is not the primary mechanism for establishing genital tuberculosis. *Ascending* - **Ascending infection** is typically seen in other sexually transmitted infections or bacterial vaginosis, where pathogens move upwards from the lower genital tract. - This is not the characteristic mode of spread for **Mycobacterium tuberculosis** to cause genital tuberculosis.

Question 1155: Which of the following is the PRIMARY risk factor most commonly associated with healthcare-associated pneumonia (HCAP)?

A. Acute care hospitalization for at least 2 days in the preceding 90 days (Correct Answer)
B. Home infusion therapy
C. Immunosuppressive disease or immunosuppressive therapy
D. Antibiotic therapy in the preceding 90 days

Explanation: ***Acute care hospitalization for at least 2 days in the preceding 90 days*** - This criterion is a **primary defining factor** for healthcare-associated pneumonia (HCAP) as it indicates recent exposure to healthcare settings where resistant pathogens are prevalent [1]. - Patients recently hospitalized are at higher risk for colonization with **multi-drug resistant organisms (MDROs)**, increasing the likelihood of difficult-to-treat infections [2]. *Home infusion therapy* - While home infusion therapy does involve healthcare contact, it is considered a **minor risk factor** for HCAP compared to recent acute hospitalization. - The level of exposure to resistant pathogens is typically lower in a home setting than in an acute care facility. *Immunosuppressive disease or immunosuppressive therapy* - Immunosuppression significantly increases a patient's **susceptibility to infection** in general, including pneumonia, but it is not the **primary diagnostic criterion** for defining HCAP [3]. - Immunocompromised patients can develop pneumonia from various sources, not exclusively from healthcare exposure. *Antibiotic therapy in the preceding 90 days* - Recent antibiotic therapy is a risk factor for developing pneumonia with **resistant pathogens**, but it is not the primary factor defining HCAP itself. - This factor influences the **choice of empiric antibiotics** due to potential resistance, rather than establishing the healthcare-associated nature of the infection.

Question 1156: Which of the following statements about amoebic liver abscess is false?

A. More common in males than females
B. More common in the right lobe of the liver
C. Metronidazole is the mainstay of treatment
D. Amoebic liver abscess is not treatable with antibiotics (Correct Answer)

Explanation: Amoebic liver abscess is not treatable with antibiotics - This statement is false because **amoebic liver abscess** (ALA) is caused by *Entamoeba histolytica*, a **protozoan parasite**, and is effectively treated with **anti-parasitic drugs**, which are a type of antimicrobial and can be considered antibiotics in a broader sense for non-bacterial infections. - While traditional **antibiotics** (designed for bacteria) are not directly effective against the parasite, **metronidazole** (an antimicrobial) is the **drug of choice** for ALA. The liquid contents of the abscess typically have a characteristic pinkish or chocolate-brown color, often referred to as 'anchovy sauce' [1]. *More common in males than females* - This statement is **true**; amoebic liver abscess is indeed observed more frequently in **males**, particularly those between **20 and 50 years** of age. - The reasons for this disparity are not fully understood but may relate to hormonal factors or exposure differences. *More common in the right lobe of the liver* - This statement is **true**; the **right lobe** of the liver is the most common site for amoebic liver abscess formation. - This is attributed to the **anatomic fact** that the right lobe receives **more blood flow** from the superior mesenteric vein, which drains the colon where *Entamoeba histolytica* typically resides. *Metronidazole is the mainstay of treatment* - This statement is **true**; **metronidazole** is the **drug of choice** for the treatment of amoebic liver abscess [1]. - It is highly effective in eradicating the **trophozoites** of *Entamoeba histolytica* from the liver.

Question 1157: Earliest and often the only presentation of TB kidney is

A. Blood in urine (Correct Answer)
B. Sterile pyuria
C. Colicky abdominal pain
D. Kidney stones

Explanation: ***Blood in urine*** - **Hematuria** (blood in urine) is a common initial presentation of renal TB, often microscopic and sometimes macroscopic, appearing early due to inflammation and ulceration of the urinary tract. - The presence of **blood in urine** without significant pain or other classic infection signs can confuse the diagnosis, making it an "early" and *misleading* symptom without further investigation. *Sterile pyuria* - While **sterile pyuria** (pus cells in urine without bacterial growth on routine cultures) is highly suggestive of **TB kidney**, it tends to appear later in the disease progression as more significant renal damage and inflammation occur. - Early stages might not show prominent pyuria, and **hematuria** often precedes it as the initial symptom of tissue damage. *Colicky abdominal pain* - **Colicky abdominal pain** is more commonly associated with obstruction, such as from stone passage or severe hydronephrosis, which are typically later complications of TB kidney, not early presentations. - Early renal TB typically involves the parenchyma and calyces, not usually leading to significant obstruction that would cause colicky pain. *Kidney stones* - **Kidney stones** (renal calculi) are a potential long-term complication of renal TB due to metabolic changes, inflammation, and cellular debris, but they are not an *early* or *initial* symptom [1]. - The formation of stones usually indicates more advanced disease or chronic inflammation within the urinary tract [1].

Question 1158: Which of the following statements about hydatid cyst of the liver is true?

A. Most common causative organism is Echinococcus granulosus. (Correct Answer)
B. Mostly asymptomatic.
C. Most commonly located in the right lobe of the liver.
D. Hepatic resection is a treatment option, but not the first-line treatment.

Explanation: **Most common causative organism is *Echinococcus granulosus*** - *Echinococcus granulosus* is the **predominant species** responsible for the majority of human hydatid cysts globally, particularly in the liver and lungs [1]. - This parasite is transmitted through the **fecal-oral route**, involving canids (dogs) as definitive hosts and livestock (sheep, cattle) as intermediate hosts [1]. *Mostly asymptomatic* - While some small uncomplicated cysts can be asymptomatic, many hydatid cysts, especially in the liver, eventually become **symptomatic** due to their size, mass effect, or complications [1]. - Symptoms often include **abdominal pain, jaundice**, or signs of rupture, making them clinical rather than primarily asymptomatic. *Most commonly located in the right lobe of the liver* - While the liver is the most common organ affected by hydatid disease, the cysts show **no particular predilection for the right or left lobe** and can be found throughout the hepatic parenchyma. - The **liver is the primary site** because it is the first capillary bed encountered by the oncospheres after penetration of the intestinal wall, but a specific lobe predominance is not consistently observed. *Hepatic resection is a treatment option, but not the first-line treatment* - **Hepatic resection (surgical removal)** of hydatid cysts is often considered the **definitive treatment** for accessible, symptomatic, or complicated cysts, aiming for complete cyst removal and prevention of recurrence. - While percutaneous aspiration, injection, and re-aspiration (PAIR) with scolicidal agents is an alternative for selected cases, **surgical resection remains a primary and frequently preferred treatment option**, especially for larger or complicated cysts and when feasible.

Question 1159: Which of the following is NOT more commonly seen in Klebsiella Pneumonia compared to Pneumococcal Pneumonia?

A. Abscess Formation
B. Pleural Effusion
C. Cavitation
D. Lower lobe involvement (Correct Answer)

Explanation: ***Lower lobe involvement*** - **Pneumococcal pneumonia** classically presents with **lobar pneumonia**, often affecting a single lobe, which can be any lobe but frequently involves the lower lobes. - While Klebsiella pneumonia can involve any lobe, the frequency of lower lobe involvement is not definitively higher than in pneumococcal pneumonia, making it a feature not *more* commonly seen in Klebsiella. *Abscess Formation* - **Klebsiella pneumonia** is notoriously associated with **necrosis** and abscess formation within the lung parenchyma due to its highly virulent polysaccharide capsule. - Abscesses are less common in uncomplicated **pneumococcal pneumonia**, which more typically causes lobar consolidation without significant tissue destruction [1]. *Pleural Effusion* - **Klebsiella pneumonia** is well-known for causing severe inflammation and an increased likelihood of developing a **parapneumonic pleural effusion**, often a complicated or empyematous one. - While pleural effusions can occur in pneumococcal pneumonia, they are generally less frequent and less severe than those seen with Klebsiella. *Cavitation* - **Cavitation** (breakdown of lung tissue forming cavities) is a hallmark of severe **Klebsiella pneumonia**, often observed as a consequence of extensive necrosis [1]. - Cavitation is a rare finding in **pneumococcal pneumonia**, which tends to resolve with consolidation rather than destructive changes.

Question 1160: Which of the following statements about Koplik spots is true?

A. Pathognomonic of measles.
B. Present on buccal mucosa opposite the molars.
C. Not always present.
D. All of the options. (Correct Answer)

Explanation: All of the options. - Koplik spots are pathognomonic of measles, meaning their presence is a definitive indicator of the disease [1]. - They typically appear as tiny, white spots on an erythematous base on the buccal mucosa, often opposite the molars [1]. Pathognomonic of measles. - While Koplik spots are a hallmark sign of measles, stating this is true alone doesn't encompass all true aspects for this question [1]. - Their presence, however, is a strong diagnostic indicator of rubeola. Present on buccal mucosa opposite the molars. - This is a correct description of their typical location, but not a complete answer to the question "Which of the following statements about Koplik spots is true?" if other options also hold true [1]. - These spots are found on the mucous membrane lining the inside of the cheeks [1]. Not always present. - Koplik spots are transient and may not be present throughout the entire course of measles, particularly if a patient is seen later in the disease [1]. - They also can be missed if not specifically looked for or if they are very few in number.

Practice by Chapter

Principles of Antimicrobial Therapy

Practice Questions

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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