Infectious Diseases — MCQs

A febrile 23-year-old college student presents with fatigue and difficulty swallowing. Physical examination reveals exudative tonsillitis, palatal petechiae, cervical lymphadenopathy, and tender hepatosplenomegaly. A complete blood count shows mild anemia, lymphocytosis with approximately 30% of the lymphocytes exhibiting atypical features, and mild thrombocytopenia. The Coombs' test is positive. Which of the following is the most likely complication of this syndrome?

Q1348

While discharging a patient of meningitis due to Haemophilus influenzae, what is the essential step you would take?

Q1349

Which of the following parts of the body is not affected by leprosy?

Q1350

The most common cause of epididymitis is

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 1341: Nocardia infection is associated most commonly with:

A. Lung abscess (Correct Answer)
B. Brain abscess
C. Subcutaneous abscess
D. Liver abscess

Explanation: ***Lung abscess*** - **Nocardia** infections most commonly affect the lungs, leading to **pulmonary nocardiosis** which can manifest as pneumonia, nodules, or abscesses. - Initial infection typically occurs via **inhalation of Nocardia spores** from the dust or soil. *Liver abscess* - **Liver abscesses** are more commonly associated with **bacterial infections** like *Klebsiella pneumoniae* or *Entamoeba histolytica*. - While nocardial disseminated disease can affect the liver, it is not the most common primary site of abscess formation. *Brain abscess* - **Brain abscesses** are a serious complication if Nocardia disseminates, particularly in **immunocompromised individuals**. - However, the most common clinical presentation of Nocardia infection itself is pulmonary, with brain involvement being a secondary event. *Subcutaneous abscess* - **Subcutaneous abscesses** due to *Nocardia* can occur, often following **skin trauma** or direct inoculation, but are less common than pulmonary involvement. - This presentation is typically seen in patients with **cutaneous nocardiosis**, which is distinct from the more common systemic infection.

Question 1342: Which of the following infections is least likely to be associated with nephropathies?

A. Salmonella enterica serotype Typhi
B. Staphylococcus epidermidis (Correct Answer)
C. Hepatitis B
D. Legionella pneumophila

Explanation: Staphylococcus epidermidis - While Staphylococcus epidermidis can cause infections, particularly with prosthetic devices or in immunocompromised individuals, it is least commonly associated with the development of specific nephropathies. - Unlike the other options, it does not typically trigger well-recognized immune-mediated glomerular diseases [1] or direct renal damage that would be termed a nephropathy in the same context. Salmonella enterica serotype Typhi - Typhoid fever, caused by Salmonella Typhi, can lead to various complications, including renal complications like acute kidney injury or glomerulonephritis in severe cases. - The systemic inflammatory response and potential for immune complex deposition can contribute to nephropathy. Hepatitis B - Chronic hepatitis B virus (HBV) infection is a well-established cause of various nephropathies, particularly membranous nephropathy and membranoproliferative glomerulonephritis, due to immune complex deposition. - The viral antigens and antibodies form complexes that can deposit in the glomeruli, leading to inflammation and kidney damage. Legionella pneumophila - Legionnaires' disease, caused by Legionella pneumophila, is frequently associated with acute kidney injury (AKI), often due to rhabdomyolysis, direct renal tubular injury, or systemic inflammation. - Although primarily known for its respiratory effects, severe Legionella infection can indeed lead to significant renal involvement and nephropathy.

Question 1343: All are true about amoebic liver abscess except?

A. Multifocal abscess cannot be treated by aspiration
B. More common in left side (Correct Answer)
C. More common in female
D. Metronidazole is mainstay of treatment

Explanation: Amoebic liver abscesses are much more common in the right lobe of the liver (>80-90%) due to the portal venous flow from the colon predominantly going to the right lobe [1]. The left lobe is rarely affected, and multifocal abscesses are also less common than a single right-sided lesion. Metronidazole is indeed the drug of choice for treating amoebic liver abscesses due to its excellent tissue penetration and efficacy against Entamoeba histolytica. Treatment for 7-10 days typically eradicates the trophozoites in the abscess and in the intestinal tract. While single, large abscesses often benefit from aspiration, multifocal abscesses are generally not amenable to aspiration due to their diffuse nature and numerous locations. Medical treatment with metronidazole is the primary approach for multifocal amoebic liver abscesses. Amoebic liver abscesses are actually more common in males than females, with a male-to-female ratio typically ranging from 7:1 to 10:1. This predisposition in males is not fully understood but may be related to hormonal factors or lifestyle differences.

Question 1344: Round worms cause all of the following conditions, except:

A. Intestinal obstruction
B. Intestinal perforation (Correct Answer)
C. Obstructive jaundice
D. Pancreatitis

Explanation: ***Intestinal perforation*** - While **Ascaris lumbricoides** can cause obstructions, migration, and inflammation, **bowel perforation** is an extremely rare complication, usually associated with massive worm burdens or pre-existing bowel damage. - The thick cuticle of the adult worm is not typically capable of directly perforating healthy intestinal wall tissue. *Obstructive jaundice* - **Ascaris worms** can migrate into the **biliary tree**, especially the common bile duct, leading to its obstruction. - This obstruction can cause symptoms and signs of **obstructive jaundice**, such as yellowing of skin and eyes, dark urine, and pale stools. *Pancreatitis* - Migrating adult **Ascaris worms** can enter the **pancreatic duct** via the ampulla of Vater. - This can obstruct the duct and lead to **acute pancreatitis**, characterized by severe abdominal pain and elevated pancreatic enzymes. *Intestinal obstruction* - A large number of **adult Ascaris worms** can form a tightly packed bolus within the lumen of the small intestine. - This **worm bolus** can cause a mechanical blockage, leading to **intestinal obstruction**, which is a common and serious complication.

Question 1345: An abattoir worker presented with a lesion on his hand that progressed to form an ulcer. A smear was taken from the ulcer and sent to the laboratory for investigation. What is the diagnosis?

A. Cutaneous anthrax (Correct Answer)
B. Infected rodent ulcer
C. Ulcerating melanoma (irregular pigmentation)
D. Carbuncle (ulceration possible)

Explanation: ***Cutaneous anthrax*** - The patient's occupation as an **abattoir worker** places him at high risk for exposure to *Bacillus anthracis* from infected animal products [1]. - Cutaneous anthrax typically presents as a small **papule** that progresses to a **vesicle**, then to a characteristic **painless ulcer with a black eschar** (malignant pustule), fitting the description [1]. *Ulcerating melanoma (irregular pigmentation)* - While melanomas can ulcerate, they typically present with **irregular pigmentation**, **asymmetry**, and **border irregularity**, which are not mentioned. - There is no specific occupational link to abattoir work for melanoma, unlike anthrax. *Infected rodent ulcer* - A "rodent ulcer" is a lay term for a **basal cell carcinoma**, which is a type of skin cancer. - These typically grow slowly and may ulcerate, but they are not acutely infectious and lack the direct occupational exposure context. *Carbuncle (ulceration possible)* - A carbuncle is a **deep-seated skin infection** involving multiple hair follicles, often caused by *Staphylococcus aureus*. - While it can ulcerate and be painful, it's less likely in an abattoir worker context for a singular lesion without systemic signs of severe staphylococcal infection.

Question 1346: A patient from Himachal Pradesh presents with fever for 5 days, altered sensorium, increased jugular venous pressure, maculopapular rash, and erythema on the back with black necrotic tissue. What is the most appropriate treatment option?

A. Aminoglycosides
B. Chloramphenicol
C. Doxycycline (Correct Answer)
D. Tetracycline

Explanation: ***Doxycycline*** - The clinical picture strongly suggests **scrub typhus**, an endemic illness in Himachal Pradesh, characterized by fever, altered sensorium, rash, and an **eschar** (black necrotic tissue) [1]. - **Doxycycline** is the first-line treatment for scrub typhus, effectively targeting *Orientia tsutsugamushi*. *Aminoglycosides* - These antibiotics primarily target **gram-negative bacteria** and **tuberculosis**, which do not fit the clinical presentation of scrub typhus. - Aminoglycosides are **ineffective** against *Orientia tsutsugamushi*, the causative agent of scrub typhus. *Chloramphenicol* - While historically used for scrub typhus, **chloramphenicol** is now a second-line option due to potential severe side effects like reversible bone marrow suppression and **aplastic anemia**. - **Doxycycline** is preferred due to its superior safety profile and equivalent efficacy. *Tetracycline* - **Tetracycline** is a broad-spectrum antibiotic that could be effective, but **doxycycline** is a more potent and better-tolerated tetracycline derivative. - **Doxycycline** offers better pharmacokinetic properties, allowing for once-daily dosing in most cases.

Question 1347: A febrile 23-year-old college student presents with fatigue and difficulty swallowing. Physical examination reveals exudative tonsillitis, palatal petechiae, cervical lymphadenopathy, and tender hepatosplenomegaly. A complete blood count shows mild anemia, lymphocytosis with approximately 30% of the lymphocytes exhibiting atypical features, and mild thrombocytopenia. The Coombs' test is positive. Which of the following is the most likely complication of this syndrome?

A. Splenic rupture (Correct Answer)
B. Diarrhea
C. Acute cholecystitis
D. Ascending cholangitis

Explanation: **Splenic rupture** - The patient's symptoms (fatigue, difficulty swallowing, exudative tonsillitis, palatal petechiae, cervical lymphadenopathy, hepatosplenomegaly, atypical lymphocytosis, and positive Coombs' test) are highly suggestive of **infectious mononucleosis** [1]. - **Splenic enlargement** (splenomegaly) is common in infectious mononucleosis, making the spleen vulnerable to rupture, especially with trauma or increased abdominal pressure [2]. *Acute cholecystitis* - Not a typical complication of infectious mononucleosis, which primarily affects lymphoid tissues and can involve the liver and spleen [3]. - Usually caused by **gallstone obstruction** of the cystic duct, leading to gallbladder inflammation. *Diarrhea* - Not a characteristic symptom or complication of infectious mononucleosis. - More commonly associated with **gastrointestinal infections**. *Ascending cholangitis* - An infection of the bile ducts, usually due to **biliary obstruction** by stones or strictures, not a known complication of infectious mononucleosis. - Symptoms include Charcot's triad (fever, right upper quadrant pain, jaundice).

Question 1348: While discharging a patient of meningitis due to Haemophilus influenzae, what is the essential step you would take?

A. Assess the patient's developmental milestones
B. Refer the patient for physical rehabilitation
C. Perform an EEG to assess brain activity
D. Test for hearing loss using auditory response testing (Correct Answer)

Explanation: ***Test for hearing loss using auditory response testing*** - **Hearing loss** is a common and serious complication of *Haemophilus influenzae* meningitis, potentially affecting up to 30% of survivors, and early detection is crucial for intervention [1]. - **Auditory brainstem response (ABR) testing** is a reliable method to assess hearing function in patients, especially children, after meningitis. *Perform an EEG to assess brain activity* - While meningitis can cause neurological complications like seizures, an **EEG** is primarily indicated for assessing **seizure activity** or other significant alterations in brain electrical function, not as a routine discharge step for all *Haemophilus influenzae* meningitis patients [2]. - An EEG would be performed if there were **clinical signs of seizures** or other neurological deficits requiring immediate investigation during hospitalization, rather than as a discharge routine. *Assess the patient's developmental milestones* - Assessing **developmental milestones** is important for all children, especially after a severe illness like meningitis, but it is a **long-term follow-up** concern and not an essential **immediate discharge step** focused on a specific, common complication. - Developmental assessments are typically part of routine pediatric check-ups and ongoing neurodevelopmental surveillance, rather than a single acute discharge intervention. *Refer the patient for physical rehabilitation* - **Physical rehabilitation** is necessary if the patient has experienced **motor deficits** or other physical impairments due to meningitis-related complications, such as stroke or cerebral palsy. - However, it is not an essential universal discharge step for all meningitis patients; it is only indicated if specific rehabilitation needs have been identified.

Question 1349: Which of the following parts of the body is not affected by leprosy?

A. Nasal mucosa
B. Testes
C. Axilla
D. Ovary (Correct Answer)

Explanation: ***Ovary*** - The **ovaries** are generally not affected by *Mycobacterium leprae* due to their internal location and higher core body temperature. - The bacterium thrives in **cooler temperatures**, which is why it typically affects superficial tissues and distal extremities. *Testes* - The **testes** are located externally and have a lower temperature, making them susceptible to *Mycobacterium leprae* infection. - Involvement can lead to severe damage, including **atrophy** and **infertility**. *Nasal mucosa* - The **nasal mucosa** is a common site of infection and a major portal of entry and exit for *Mycobacterium leprae*. - Early lesions can cause **nasal stuffiness** and progress to septal perforation and collapse of the nasal bridge. *Axilla* - Peripheral nerves in the **axilla**, such as the median, ulnar, and radial nerves, can be affected by leprosy. - Nerve involvement may lead to **sensory loss** and **motor weakness** in the upper limbs.

Question 1350: The most common cause of epididymitis is

A. Proteus infection
B. Tubercular infection
C. Gonococcal infection
D. Chlamydia infection (Correct Answer)

Explanation: ***Chlamydia infection*** - **Chlamydia trachomatis** is the most frequent cause of epididymitis in sexually active men younger than 35 years. [1] - It is transmitted sexually and often co-occurs with **gonorrhea**, though Chlamydia alone is a significant pathogen. [1] *Gonococcal infection* - While **Neisseria gonorrhoeae** can cause epididymitis, it is less common than Chlamydia as a sole pathogen, though it frequently co-infects with Chlamydia. [1] - It typically results in more acute and severe symptoms, including a purulent urethral discharge. [1] *Proteus infection* - **Proteus species** are more common causes of epididymitis in older men, often associated with **urinary tract infections** or instrumentation. - This bacterial infection is typically seen in the context of other urinary system abnormalities rather than as a primary sexually transmitted infection. *Tubercular infection* - **Tuberculosis (TB) epididymitis** is uncommon in developed countries but can occur in endemic areas or immunocompromised individuals. - It typically presents with a more indolent course, often with a firm or nodular epididymis, and usually indicates systemic TB.

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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