Infectious Diseases Practice Questions

Q: Most characteristic oral lesion associated with HIV is:

Oral hairy leukoplakia. ***Oral hairy leukoplakia*** - This lesion is a **white, corrugated patch** that typically appears on the lateral borders of the tongue and cannot be scraped off. - It is caused by the **Epstein-Barr virus (EBV)** and is a strong indicator of **HIV progression** to AIDS, especially in individuals with declining CD4 counts. *Herpes simplex* - While common in HIV-positive individuals, **herpes simplex** presents as painful vesicles and ulcers, often recurrent, and is not exclusive to HIV [2]. - Oral hairy leukoplakia is far more specific and characteristic as an **early indicator** of HIV-related immune suppression. *Gingivitis* - **Gingivitis** is widespread inflammation of the gums and is very common in the general population, not specifically characteristic of HIV infection solely [1]. - Although more severe forms like **necrotizing ulcerative gingivitis** can be seen in advanced HIV, simple gingivitis is not the most characteristic oral lesion [1]. *Aphthous ulcers* - **Aphthous ulcers** are common, painful, recurrent oral lesions that can occur in the general population and are not specific to HIV [3]. [4] - While they can be more severe and persistent in HIV-positive individuals, they lack the diagnostic specificity seen with oral hairy leukoplakia [1].

Q: Most common site of tuberculosis in gastrointestinal tract is ?

Ileocecal junction. ***Ileocecal junction*** - The **ileocecal junction** is the most common site for gastrointestinal tuberculosis due to its rich lymphatic tissue, physiological stasis, and abundant fluid absorption. - The presence of Peyer's patches and constant exposure to luminal contents make it susceptible to colonization and granuloma formation by *Mycobacterium tuberculosis*. *Small intestine* - While the small intestine can be affected by tuberculosis, the **ileocecal junction** specifically is the predominant site within the small intestine and overall GI tract. - Other parts of the small intestine, such as the jejunum and duodenum, are less commonly involved due to faster transit time and fewer lymphoid follicles. *Stomach* - The **stomach** is rarely affected by tuberculosis due to its highly acidic environment, which is inhibitory to mycobacterial growth. - Gastric involvement, when it occurs, usually presents as ulcers or pyloric obstruction, but it is not the most common site. *Rectum* - The **rectum** is an uncommon site for gastrointestinal tuberculosis; when involved, it often presents with strictures or ulcers. - Rectal tuberculosis is typically seen in patients with disseminated disease or in immunocompromised individuals.

Q: Reactivation tuberculosis is almost exclusively a disease of the -

Lungs. Lungs - Reactivation tuberculosis (TB) predominantly affects the lungs, presenting as secondary pulmonary TB [1]. - It arises from the reactivation of dormant Mycobacterium tuberculosis bacteria in the lungs, often decades after primary infection [3]. Joints - While TB can affect joints (known as Pott's disease when it affects the spine), it is a less common manifestation than pulmonary involvement, particularly in reactivation [2]. - Joint involvement typically occurs via hematogenous spread from a primary pulmonary focus [2]. Brain - Tuberculosis of the brain, or tuberculous meningitis, is a severe but less common extrapulmonary form of TB [2]. - It usually results from the rupture of a subpial or subependymal tubercle into the subarachnoid space. Bones - Bone TB is another form of extrapulmonary tuberculosis, often involving the spine [2]. - Like joint involvement, it is less frequently seen compared to the almost exclusive pulmonary involvement in reactivation.

Q: A patient with large, penetrating vegetations on his mitral and aortic valves develops severe headaches. Funduscopic examination reveals papilledema. CT scan of the brain demonstrates a ring-enhancing lesion. Which of the following organisms is the most likely cause of the patient's disorder?

Staphylococcus aureus. ***Staphylococcus aureus*** - This organism is a common cause of **infective endocarditis**, particularly in patients with intravenous drug use, and is known for producing **large, destructive vegetations** that can readily embolize [2]. - The development of **severe headaches**, **papilledema**, and a **ring-enhancing brain lesion** strongly suggests a **septic embolism** leading to a **brain abscess**, a known complication of infective endocarditis caused by virulent organisms like *S. aureus* [1], [2]. *Herpesvirus* - Herpesvirus infections, such as **HSV-1**, can cause **encephalitis**, which might present with headaches and neurological signs, but they are not typically associated with **infective endocarditis** or the formation of **septic emboli** from heart valves. - While herpes encephalitis can cause ring-enhancing lesions in specific brain regions (e.g., temporal or frontal lobes), the primary presentation here points to a systemic embolic source from the heart. *Streptococcus pneumoniae* - *Streptococcus pneumoniae* can cause endocarditis, though it is less common than *Staphylococcus aureus* and often occurs in patients with pre-existing valvular disease. - While septic emboli can occur, *S. pneumoniae* endocarditis is not as frequently associated with **large, destructive vegetations** and subsequent brain abscess formation as *S. aureus* [2]. *Mycobacterium tuberculosis* - **Tuberculous meningitis** can cause severe headaches, papilledema, and ring-enhancing lesions (tuberculomas) in the brain. - However, **tuberculous_endocarditis** is extremely rare and typically does not manifest with large, destructive vegetations or, more importantly, with a primary infectious source from the heart valves as indicated by the "large, penetrating vegetations."

Q: Which of the following is the leading cause of death in brucellosis?

Endocarditis. ***Endocarditis*** - **Endocarditis** is the most common cause of death in brucellosis, particularly when involving the **aortic valve** [1]. - It often requires a combination of prolonged **antibiotic therapy** and **surgical intervention**. *Pneumonia* - While pulmonary involvement can occur in brucellosis, including **bronchitis** and **pneumonia**, it is rarely the leading cause of death. - Respiratory symptoms are generally mild and respond well to treatment. *Suppurative abscesses* - **Focal abscesses** can form in various organs in brucellosis, such as the liver or spleen [1]. - However, while serious, they are not as frequent a cause of mortality as endocarditis. *Mycotic aneurysms* - Though rare, **vascular complications** like mycotic aneurysms can occur in brucellosis, potentially leading to rupture and death. - However, their incidence is much lower compared to the mortality associated with brucella endocarditis.

Q: Which of the following is not a complication of infective endocarditis?

Myocardial infarction. ***Myocardial infarction*** - While infective endocarditis can lead to various cardiac complications, **myocardial infarction** due to direct coronary artery occlusion by emboli from vegetations is **rare** and not considered a typical complication. [1] - Myocardial infarction is more commonly associated with **atherosclerotic coronary artery disease**. *Myocardial ring abscess* - This is a common and severe local complication of infective endocarditis, often occurring in cases involving **virulent organisms** or **prosthetic valves**. [1] - An abscess can extend into the **myocardium**, conduction system, or pericardium, leading to heart block or valvular dehiscence. *Focal and diffuse glomerulonephritis* - These are **immune-mediated renal complications** of infective endocarditis, caused by the deposition of immune complexes in the glomeruli. [1] - Often presents with **hematuria**, proteinuria, and renal impairment, reflecting the systemic inflammatory response. [1] *Suppurative pericarditis* - This can occur if the infection from the endocarditic vegetation extends into the **pericardial space**, either directly or via a myocardial abscess. - It involves **purulent inflammation** of the pericardium, leading to chest pain, fever, and potentially tamponade.

Q: True regarding leptospirosis is?

Person to person transmission rare. ***Person to person transmission rare*** - Leptospirosis is primarily a **zoonotic disease** transmitted through contact with infected animal urine or contaminated environments (water, soil). - Human-to-human transmission is **extremely rare** and not a significant mode of spread. *Fluoroquinolones are the DOC* - **Doxycycline** and **penicillin G** (or ceftriaxone) are the **drugs of choice** for treating leptospirosis, depending on disease severity. - While fluoroquinolones like ciprofloxacin can have some activity, they are **not considered first-line agents** for leptospirosis. *Rats are the only reservoirs* - While **rats** are common and important reservoirs, many other animals, including **domestic livestock** (cattle, pigs), **dogs**, and **wildlife**, can also be carriers of *Leptospira* bacteria. - The disease is maintained in diverse animal populations globally. *Hepatorenal syndrome occurs in 50% cases* - **Severe leptospirosis**, also known as **Weil's disease**, causes **hepatic and renal dysfunction**, but this complication occurs in a smaller percentage of cases, typically **5-10%**, not 50%. - The majority of leptospirosis infections are mild and self-limiting.

Q: WHO AIDS defining illnesses are all EXCEPT:

Persistent generalized lymphadenopathy. ***Persistent generalized lymphadenopathy*** - While associated with HIV infection, **persistent generalized lymphadenopathy** itself is not classified as an **AIDS-defining illness** by the WHO or CDC, but rather a common manifestation of chronic HIV infection (Stage 1 or 2) [1]. - AIDS-defining illnesses are typically severe opportunistic infections or cancers that occur when the immune system is severely compromised (CD4 count below 200 cells/µL). *P. carinii pneumonia* - **P. carinii pneumonia** (now known as **Pneumocystis jirovecii pneumonia** or **PJP**) is a classic and common **AIDS-defining opportunistic infection**. - Its presence indicates severe immunosuppression, often with CD4 counts below 200 cells/µL. *CMV retinitis* - **Cytomegalovirus (CMV) retinitis** is a severe opportunistic infection, particularly of the eye, that is recognized as an **AIDS-defining illness**. - It signifies profound immunodeficiency, typically with CD4 counts below 50 cells/µL. *Oropharyngeal candidiasis* - While common in HIV-infected individuals, **oropharyngeal candidiasis** (thrush) alone is generally not considered an **AIDS-defining illness** [1]. - It is classified as an HIV Stage 2 condition, indicating moderate immune compromise rather than severe, AIDS-defining immunosuppression [1].

Question 1

Most characteristic oral lesion associated with HIV is:

Accepted Answer

Oral hairy leukoplakia

Answer

Herpes simplex

Answer

Gingivitis

Answer

Aphthous ulcers

Question 2

Most common site of tuberculosis in gastrointestinal tract is ?

Accepted Answer

Ileocecal junction

Answer

Small intestine

Answer

Stomach

Answer

Rectum

Question 3

Reactivation tuberculosis is almost exclusively a disease of the -

Accepted Answer

Lungs

Answer

Joints

Answer

Brain

Answer

Bones

Question 4

Following urinary tract infection associated with extraction of a bladder stone, a 64-year-old woman developed gram-negative septicemia. Which statement is true for gram-negative bacterial septicemia?

Accepted Answer

Many of the adverse changes can be accounted for endotoxin release.

Answer

Pseudomonas is the most common organism isolated.

Answer

Central venous pressure (CVP) is high.

Answer

The cardiac index is low.

Question 5

A patient with large, penetrating vegetations on his mitral and aortic valves develops severe headaches. Funduscopic examination reveals papilledema. CT scan of the brain demonstrates a ring-enhancing lesion. Which of the following organisms is the most likely cause of the patient's disorder?

Accepted Answer

Staphylococcus aureus

Answer

Herpesvirus

Answer

Streptococcus pneumoniae

Answer

Mycobacterium tuberculosis

Question 6

Which of the following is the leading cause of death in brucellosis?

Accepted Answer

Endocarditis

Answer

Pneumonia

Answer

Suppurative abscesses

Answer

Mycotic aneurysms

Question 7

Which of the following is not a complication of infective endocarditis?

Accepted Answer

Myocardial infarction

Answer

Focal and diffuse glomerulonephritis

Answer

Myocardial ring abscess

Answer

Suppurative pericarditis

Question 8

The typical CSF profile in cases of viral meningitis after 48 hours of onset is -

Accepted Answer

Lymphocytic pleocytosis, normal glucose level, normal or slightly elevated protein level

Answer

Neutrophilic pleocytosis, raised glucose level, normal protein level

Answer

Lymphocytic pleocytosis, low glucose level, low protein level

Answer

Neutrophilic pleocytosis, normal glucose level, elevated protein level

Question 9

True regarding leptospirosis is?

Accepted Answer

Person to person transmission rare

Answer

Fluoroquinolones are the DOC

Answer

Rats are the only reservoirs

Answer

Hepatorenal syndrome occurs in 50% cases

Question 10

WHO AIDS defining illnesses are all EXCEPT:

Accepted Answer

Persistent generalized lymphadenopathy

Answer

P. carinii pneumonia

Answer

CMV retinitis

Answer

Oropharyngeal candidiasis

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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