Infectious Diseases Practice Questions

Q: Which of the following is a known risk factor for cholangiocarcinoma?

Clonorchis sinensis infestation. ***Clonorchis sinensis infestation*** - **Clonorchis sinensis**, also known as the Chinese liver fluke, is a well-established and significant risk factor for the development of **cholangiocarcinoma**. - Chronic inflammation and irritation of the bile ducts caused by the parasite are believed to promote malignant transformation. *Giardia lamblia (intestinal protozoa) infection* - **Giardia lamblia** is a common intestinal parasite causing giardiasis, characterized by diarrhea and malabsorption. - While it affects the gastrointestinal tract, there is **no known association** between *Giardia* infection and an increased risk of cholangiocarcinoma. *Paragonimus westermani infestation* - **Paragonimus westermani** is a lung fluke that primarily causes paragonimiasis, affecting the lungs and leading to cough and hemoptysis. - This parasite is not associated with direct bile duct inflammation or an increased risk of **cholangiocarcinoma**. *Ascaris lumbricoides (roundworm) infection* - **Ascaris lumbricoides** is a large intestinal roundworm that can cause intestinal obstruction or nutrient deficiencies. - Although it can occasionally migrate into the biliary tree, it is **not considered a risk factor** for cholangiocarcinoma [1].

Q: Which of the following statements about epididymo-orchitis of mumps is incorrect?

It is the most common manifestation of mumps infection. ***It is the most common manifestation of mumps infection*** - This statement is **INCORRECT**. The most common manifestation of mumps infection is **parotitis** (inflammation of the parotid glands), not epididymo-orchitis. - About **one-third of mumps infections are asymptomatic**, and **orchitis** occurs in only 20-30% of post-pubertal males with mumps. - Epididymo-orchitis is a significant complication but not the predominant presentation. *Testicular enlargement usually resolves in 1 week* - This statement is correct. The **swelling and tenderness** of mumps orchitis typically resolve within **3-7 days** (approximately 1 week). - The acute phase of inflammation and pain generally subsides within this timeframe, though complete resolution may take longer. *Complete sterility is a rare outcome in these patients.* - This statement is correct. While mumps orchitis can cause **testicular atrophy** and **impaired spermatogenesis**, **complete sterility is rare**. - Even with bilateral involvement, some degree of fertility is usually preserved as not all seminiferous tubules are damaged. *Bilateral testicular involvement is seen in 10-30% of cases.* - This statement is correct. Mumps orchitis is predominantly **unilateral**, with **bilateral involvement** occurring in approximately **10-30%** of affected individuals. - Most cases involve only one testis, reducing the risk of severe fertility impairment.

Q: Which hepatitis infection is most commonly associated with immune thrombocytopenic purpura?

Hepatitis C infection. ***Hepatitis C infection*** - **Hepatitis C** is well-established for causing various **extrahepatic manifestations**, including mixed cryoglobulinemia, membranoproliferative glomerulonephritis, and **immune thrombocytopenic purpura (ITP)**. - The mechanism involves chronic viral stimulation leading to the production of **autoantibodies** against platelets and megakaryocytes, or direct viral effects on bone marrow. *Hepatitis A infection* - **Hepatitis A** is an **acute, self-limiting viral infection** [1] that typically does not lead to chronic liver disease or significant extrahepatic manifestations like ITP. - There are rare reports of transient thrombocytopenia in acute hepatitis A, but it is not commonly associated with chronic ITP. *Hepatitis B infection* - While **Hepatitis B** can cause extrahepatic manifestations such as polyarteritis nodosa and glomerulonephritis, its association with **immune thrombocytopenic purpura (ITP)** is less frequent and not as strong as with Hepatitis C. - HBV-associated thrombocytopenia is more often related to **hypersplenism** in cirrhotics or direct viral bone marrow suppression, rather than immune-mediated destruction. *Hepatitis D infection* - **Hepatitis D (HDV)** is a **defective virus** that requires co-infection with Hepatitis B virus (HBV) to replicate. - Its extrahepatic manifestations are primarily linked to the underlying **HBV infection**, and there is no strong, independent association with immune thrombocytopenic purpura.

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].

Q: The most common cause of seizures in a patient of AIDS is

Toxoplasmosis. ***Toxoplasmosis*** - **Cerebral toxoplasmosis** is the most common cause of focal neurological deficits and seizures in patients with AIDS [1]. - It typically presents with multiple **ring-enhancing lesions** on MRI, often in the basal ganglia [1]. *Cryptococcal meningitis* - While common in AIDS, **cryptococcal meningitis** primarily causes headache, fever, and altered mental status, but seizures are less frequent. - It is diagnosed by identifying **Cryptococcus neoformans** in CSF. *Progressive multifocal leucoencephalopathy* - PML is a demyelinating disease caused by the **JC virus** and results in progressive neurological deficits due to white matter lesions [2]. - Seizures can occur, but this condition primarily affects **cognition** and motor function [2]. *CNS lymphoma* - **Primary CNS lymphoma** is another common CNS complication in AIDS, often presenting as a solitary or multiple ring-enhancing lesion [1]. - While it can cause seizures, it is less common than toxoplasmosis as the primary cause of seizures in this population [1].

Question 1

Which of the following is a known risk factor for cholangiocarcinoma?

Accepted Answer

Clonorchis sinensis infestation

Answer

Giardia lamblia (intestinal protozoa) infection

Answer

Ascaris lumbricoides (roundworm) infection

Answer

Paragonimus westermani infestation

Question 2

Which of the following statements about epididymo-orchitis of mumps is incorrect?

Accepted Answer

It is the most common manifestation of mumps infection

Answer

Testicular enlargement usually resolves in 1 week

Answer

Complete sterility is a rare outcome in these patients.

Answer

Bilateral testicular involvement is seen in 10-30% of cases.

Question 3

Which hepatitis infection is most commonly associated with immune thrombocytopenic purpura?

Accepted Answer

Hepatitis C infection

Answer

Hepatitis A infection

Answer

Hepatitis B infection

Answer

Hepatitis D infection

Question 4

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

Accepted Answer

Decreased haemoglobin

Answer

Pleural effusion

Answer

Thrombocytopenia

Answer

Hepatomegaly

Question 5

Most common mode of spread for genital tuberculosis is?

Accepted Answer

Hematogenous

Answer

Lymphatic

Answer

Direct

Answer

Ascending

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

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 8

Most common cause of diarrhea in AIDS patients?

Accepted Answer

Cryptosporidium

Answer

Salmonella typhimurium

Answer

Candida

Answer

Isospora

Question 9

Most common presentation of extra- pulmonary TB

Accepted Answer

Tubercular lymphadenitis

Answer

Peritoneal TB

Answer

Pericardial TB

Answer

Tubercular meningitis

Question 10

The most common cause of seizures in a patient of AIDS is

Accepted Answer

Toxoplasmosis

Answer

Cryptococcal meningitis

Answer

Progressive multifocal leucoencephalopathy

Answer

CNS lymphoma

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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