Infectious Diseases Practice Questions

Q: Tuberculosis of spine most commonly affects which vertebral segment?

Lower dorsal. ***Lower dorsal*** - The **lower dorsal** (thoracic) spine, especially T9-T12, is the most frequently affected segment in **tuberculosis of the spine** (Pott's disease) [1]. - This region's rich vascular supply, particularly the nutrient arteries, makes it a common site for hematogenous spread of *Mycobacterium tuberculosis*. *Upper dorsal* - While other segments can be affected, the **upper dorsal spine** is less commonly involved than the lower dorsal region. - Involvement here might present with similar symptoms but is statistically less frequent. *Lumbar* - The **lumbar spine** is the second most common site for spinal tuberculosis, but it is still less frequent than the lower dorsal region [1]. - Lumbar involvement typically presents with **low back pain** and neurological deficits but is not the primary site. *Cervical* - **Cervical spine** involvement in tuberculosis is rare, accounting for a small percentage of all spinal TB cases. - It can lead to severe neurological compromise due to the **narrow spinal canal** in this region.

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

Eye inflammation. ***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.

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

Mycobacterium bovis. ***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.

Q: Which of the following is NOT an extrahepatic manifestation of Hepatitis C?

Celiac Disease. ***Celiac Disease*** - Celiac disease is an **autoimmune disorder** triggered by gluten, not associated with Hepatitis C. [1] - Extrahepatic manifestations of Hepatitis C typically include **dermatological and rheumatological conditions**, which are absent in celiac disease. *Cryoglobulinemia* - Cryoglobulinemia is a common **extrahepatic manifestation** of Hepatitis C, often leading to **vasculitis**. - It presents with **skin rashes**, arthralgia, and renal issues, significantly associated with chronic Hepatitis C infection [2]. *Lichen Planus* - Lichen Planus is another **dermatological condition** frequently linked with Hepatitis C, manifesting with **itchy lesions** on skin and mucous membranes. - The exact mechanism is unclear, but it shows a significant correlation with the virus. *Glomerulonephritis* - Glomerulonephritis is also recognized as a potential **extrahepatic complication** of Hepatitis C, often resulting from **cryoglobulinemic vasculitis**. - It can lead to symptoms of **nephritis**, such as hematuria and proteinuria, reflecting kidney involvement [2].

Q: What is the commonest form of plague?

Bubonic plague. ***Bubonic plague*** - This is the **most common** form of plague, accounting for the majority of human cases [1]. - It is characterized by the development of painful, swollen lymph nodes called **buboes**, typically in the groin, armpit, or neck. *Pneumonic plague* - This form affects the **lungs** and is less common, but it is the most **virulent** and can be transmitted directly from person to person via respiratory droplets [1]. - If left untreated, bubonic or septicaemic plague can progress to secondary pneumonic plague [1]. *Septicaemic plague* - This form occurs when the bacteria **multiply in the bloodstream**, leading to widespread infection and potentially septic shock [1]. - It is less common than bubonic plague and can occur as a primary infection or as a complication of untreated bubonic plague [1]. *Hemorrhagic plague* - While plague can cause **hemorrhage** due to disseminated intravascular coagulation, "hemorrhagic plague" is not a distinct, recognized form of plague. - Bleeding is a **symptom** that can occur in severe cases of septicaemic or pneumonic plague, indicating extensive organ damage.

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

2 weeks. **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.

Q: CCR5 mutation is related to which condition ?

Resistance to HIV infection. ***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**.

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

Deep-seated. ***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.

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

CMV. ***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 1

Tuberculosis of spine most commonly affects which vertebral segment?

Accepted Answer

Lower dorsal

Answer

Upper dorsal

Answer

Lumbar

Answer

Cervical

Question 2

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

Accepted Answer

Eye inflammation

Answer

Liver inflammation

Answer

Heart inflammation

Answer

None of the options

Question 3

Major criteria for infective endocarditis include which of the following

Accepted Answer

Isolation of a typical organism from two separate blood cultures

Answer

History of injection drug use

Answer

Presence of Osler's nodes

Answer

Persistent fever for more than 4 days

Question 4

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

Accepted Answer

Mycobacterium bovis

Answer

Histoplasma capsulatum

Answer

Coccidioides immitis

Answer

Mycobacterium tuberculosis

Question 5

Which of the following is NOT an extrahepatic manifestation of Hepatitis C?

Accepted Answer

Celiac Disease

Answer

Glomerulonephritis

Answer

Cryoglobulinemia

Answer

Lichen Planus

Question 6

What is the commonest form of plague?

Accepted Answer

Bubonic plague

Answer

Pneumonic plague

Answer

Septicaemic plague

Answer

Hemorrhagic plague

Question 7

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

Accepted Answer

2 weeks

Answer

1 week

Answer

3 weeks

Answer

4 weeks

Question 8

CCR5 mutation is related to which condition ?

Accepted Answer

Resistance to HIV infection

Answer

Susceptibility to HIV infection

Answer

Resistance to HBV infection

Answer

Susceptibility to HBV infection

Question 9

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

Accepted Answer

Deep-seated

Answer

Not centripetal

Answer

Monomorphic

Answer

Superficial

Question 10

Bloody diarrhea in HIV infected patient is mostly due to ?

Accepted Answer

CMV

Answer

Cryptosporidium

Answer

Isospora

Answer

Salmonella

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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