Infectious Diseases Practice Questions

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

Decreased haemoglobin. ***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.

Q: Most common mode of spread for genital tuberculosis is?

Hematogenous. ***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.

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

Lower lobe involvement. ***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.

Q: Most common cause of diarrhea in AIDS patients?

Cryptosporidium. ***Cryptosporidium*** - **Cryptosporidium parvum** is a common opportunistic pathogen in AIDS patients, causing chronic, watery diarrhea, especially when the **CD4 count is low** [1]. - This parasite is resistant to routine chlorination, making **waterborne transmission** a significant concern. *Salmonella typhimurium* - While *Salmonella* can cause severe and recurrent gastroenteritis in AIDS patients, it is **not the most common cause** of chronic diarrhea in this population. - Salmonella infections in immunocompromised individuals often disseminate, leading to **bacteremia** beyond just diarrheal symptoms. *Candida* - *Candida albicans* is a common opportunistic pathogen in AIDS, primarily causing **oral candidiasis (thrush)** or esophagitis [2]. - While it can sometimes cause gastrointestinal symptoms, **Candida is not typically a prominent cause of diarrhea** in AIDS patients [2]. *Isospora* - **Isospora belli** is another coccidian parasite that causes chronic diarrhea in AIDS patients, particularly in tropical and subtropical regions [1]. - Although significant, it is **less common overall** compared to *Cryptosporidium* as a primary cause of diarrhea in this population [1].

Q: Most common presentation of extra- pulmonary TB

Tubercular lymphadenitis. ***Tubercular lymphadenitis*** - This is the **most common form** of extrapulmonary tuberculosis, often presenting as painless, swollen lymph nodes, especially in the cervical region [1]. - It develops when *Mycobacterium tuberculosis* disseminates from a primary pulmonary focus to regional lymph nodes, leading to granulomatous inflammation [1], [3]. *Peritoneal TB* - While a significant form of extrapulmonary TB, it is **less common** than lymphadenitis, typically presenting with abdominal pain, distension, and ascites. - Involvement of the peritoneum usually indicates hematogenous spread or direct extension from adjacent organs. *Pericardial TB* - This is a **rare but serious** form of extrapulmonary TB, often leading to pericardial effusion, constriction, or tamponade [2]. - It results from retrograde lymphatic spread or direct extension from mediastinal lymph nodes and is not the most common presentation. *Tubercular meningitis* - A **severe and life-threatening** form of extrapulmonary TB, involving the meninges of the brain and spinal cord, but it is less frequent than lymphadenitis [2]. - It is often seen in immunocompromised individuals or young children and presents with neurological symptoms [4].

Question 1

What is the commonest form of plague?

Accepted Answer

Bubonic plague

Answer

Pneumonic plague

Answer

Septicaemic plague

Answer

Hemorrhagic plague

Question 2

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

Accepted Answer

Celiac Disease

Answer

Glomerulonephritis

Answer

Cryoglobulinemia

Answer

Lichen Planus

Question 3

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 4

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 5

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

Accepted Answer

Decreased haemoglobin

Answer

Pleural effusion

Answer

Thrombocytopenia

Answer

Hepatomegaly

Question 6

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

Accepted Answer

Acute care hospitalization for at least 2 days in the preceding 90 days

Answer

Home infusion therapy

Answer

Immunosuppressive disease or immunosuppressive therapy

Answer

Antibiotic therapy in the preceding 90 days

Question 7

Most common mode of spread for genital tuberculosis is?

Accepted Answer

Hematogenous

Answer

Lymphatic

Answer

Direct

Answer

Ascending

Question 8

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

Accepted Answer

Lower lobe involvement

Answer

Abscess Formation

Answer

Pleural Effusion

Answer

Cavitation

Question 9

Most common cause of diarrhea in AIDS patients?

Accepted Answer

Cryptosporidium

Answer

Salmonella typhimurium

Answer

Candida

Answer

Isospora

Question 10

Most common presentation of extra- pulmonary TB

Accepted Answer

Tubercular lymphadenitis

Answer

Peritoneal TB

Answer

Pericardial TB

Answer

Tubercular meningitis

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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