Infectious Diseases Practice Questions

Q: Tuberculosis in HIV positive individuals is characterized by which of the following? 1. More frequent negative sputum smears. 2. More false–negative tuberculin test results. 3. More extra–pulmonary tuberculosis. 4. More cavitating lesions in lungs as shown by chest X-ray. Select the correct answer using the code given below:

1, 2 and 3 only. ***1, 2, and 3 only*** - HIV coinfection impairs cell-mediated immunity, leading to **atypical presentations** of TB [1]. All three options (more frequent negative sputum smears, more false-negative tuberculin tests, and more extrapulmonary TB) are characteristic of TB in HIV-positive individuals due to this **immunodeficiency** [2]. - The immunocompromised state often results in a **diminished inflammatory response**, making diagnosis more challenging and dissemination more likely. *1, 2, 3 and 4* - This option incorrectly includes "more cavitating lesions in lungs as shown by chest X-ray" as a characteristic feature. HIV-positive individuals, particularly those with advanced immunodeficiency, tend to have **fewer cavitating lesions** because their immune system is less capable of mounting the robust inflammatory response required for cavitation [1]. - Cavitation is more typical of **immunocompetent** individuals with pulmonary TB [1]. *3 and 4 only* - This option is incorrect because, while **more extrapulmonary tuberculosis** is characteristic, **more cavitating lesions** are generally not observed in HIV-positive individuals; in fact, the opposite is true. - The combination of these two points together makes this option largely inaccurate. *1 and 2 only* - While **more frequent negative sputum smears** and **false-negative tuberculin tests** [2] are indeed characteristic, this option is incomplete as it misses the increased prevalence of **extrapulmonary TB** [3], which is a significant feature in HIV-positive individuals. - HIV-related immunodeficiency often leads to the widespread dissemination of *Mycobacterium tuberculosis* outside the lungs [3].

Q: Which of the following is not a clinical feature of tetanus?

Loss of consciousness. ***Loss of consciousness*** - Tetanus is characterized by **spasms** and increased muscle tone, but patients typically remain **fully conscious** throughout the disease course. - The disease primarily affects the **motor neurons**, not the brain structures responsible for consciousness. *Risus sardonicus* - This is a characteristic feature of tetanus, referring to a **sustained, grotesque grin** caused by spasms of the facial muscles. - It is a classic clinical sign resulting from the **excitatory effects** of tetanospasmin on motor neurons [1]. *Respiratory failure* - This is a common and serious complication of tetanus, often leading to death, caused by **spasms of the respiratory muscles** [1]. - **Laryngeal spasms** and rigidity of the chest wall muscles impair breathing, necessitating mechanical ventilation. *Opisthotonus* - This refers to a severe, sustained **arching of the back** due to muscle spasms, causing the head and heels to bend backward. - It is a hallmark sign of generalized tetanus, reflecting profound **muscle rigidity** and uncontrolled muscle contractions [1].

Q: At present, treatment is recommended for H. pylori in association with the following except:

Functional dyspepsia without alarm features. ***Functional dyspepsia without alarm features*** - While *H. pylori* eradication can be considered for some patients with **functional dyspepsia**, it is not universally recommended as a primary treatment given the **variable and often limited symptomatic improvement**. - The decision to treat in this specific scenario often depends on individual patient factors and local epidemiology, and it's not a standard indication compared to other *H. pylori*-associated conditions. *MALT lymphoma* - **Eradication of *H. pylori*** is a cornerstone of treatment for **gastric MALT lymphoma**, often leading to remission [1]. - This is a well-established indication for *H. pylori* therapy due to the direct pathogenic link [1]. *Duodenal ulcer* - All patients with **duodenal ulcers** who test positive for *H. pylori* should receive eradication therapy [2]. - *H. pylori* infection is a major cause of **duodenal ulcers**, and eradication significantly reduces recurrence [2]. *Peptic ulcer disease* - **Eradication of *H. pylori*** is strongly recommended for all patients with **peptic ulcer disease** (gastric or duodenal) found to be *H. pylori* positive [2]. - This intervention is crucial for **healing ulcers** and preventing future recurrences and complications [2].

Q: Consider the following statements regarding Opportunistic post-splenectomy infections (OPSI): 1. Haemophilus influenzae, Neisseria meningitidis and Streptococcus pneumoniae are the most common causative agents 2. Risk is greatest in the patients who have undergone splenectomy for trauma 3. Risk is greatest within the first 2–3 years following splenectomy 4. Prophylactic vaccination should be done 2 weeks prior to elective splenectomy Which of the statements given above are correct?

1, 2 and 3. ***1, 2 and 3*** - **_Haemophilus influenzae, Neisseria meningitidis_**, and **_Streptococcus pneumoniae_** are encapsulated bacteria, making them the most common causative agents of **overwhelming post-splenectomy infection (OPSI)**. The spleen plays a crucial role in filtering these organisms. - The risk of OPSI is indeed **greatest** in patients who have undergone splenectomy for **trauma**, likely due to both the acute physiological stress and potentially less structured pre-operative vaccination protocols compared to elective splenectomies. - While OPSI can occur at any time, the risk is **highest** within the first **2–3 years** following splenectomy, but it remains a lifelong risk. *1, 2 and 4* - This option is incorrect because statement 3 is correct, and statement 4 is incorrect. - Prophylactic vaccination should optimally be done **2 weeks prior** to an elective splenectomy, but doing it **4-6 weeks prior** allows for a more robust immune response to develop. *1, 3 and 4* - This option is incorrect because statement 2 is correct, and statement 4 is incorrect. - The risk of OPSI is indeed highest in trauma patients, as they often undergo emergent splenectomy without prior vaccination. *2, 3 and 4* - This option is incorrect because statement 1 is correct, and statement 4 is incorrect. - _Haemophilus influenzae, Neisseria meningitidis_, and _Streptococcus pneumoniae_ are well-established primary pathogens responsible for OPSI.

Q: Which one of the following statements is NOT correct regarding Pyogenic Liver Abscess?

Treatment is with oral antibiotics alone. ***Treatment is with oral antibiotics alone*** - This statement is incorrect because pyogenic liver abscesses typically require **drainage** (percutaneous or surgical) in addition to **intravenous antibiotics** initially. Oral antibiotics alone are generally insufficient for definitive treatment. - The goal is to eradicate the infection, which often involves both source control (drainage) and systemic antimicrobial therapy. *It is more common in elderly, diabetics and immunocompromised patients* - This statement is correct. Factors such as **age**, **diabetes mellitus**, and **immunocompromised states** weaken the immune response, making individuals more susceptible to developing pyogenic liver abscesses [1]. - These conditions can impair the body's ability to clear bacteria effectively, increasing the risk of infection and abscess formation. *Streptococcus milleri and escherichia coli are the most common causative organisms* - This statement is correct. **_Streptococcus milleri_ (now _Streptococcus anginosus_)** is frequently implicated due to its ability to form abscesses, while **_Escherichia coli_** is common because many liver abscesses arise from biliary or enteric sources. - Other common pathogens include other **Gram-negative bacilli** and **anaerobes**, reflecting the varied etiologies. *Anorexia, fever, malaise and right upper quadrant abdominal discomfort are the most common presenting features* - This statement is correct. These are classic symptoms of liver abscess, reflecting the inflammatory process and the location of the infection [1]. - **Fever** and **right upper quadrant pain** are particularly prominent and should raise suspicion for a liver abscess [1].

Q: An adult man presents with the clinical condition shown in the image, and a Gram stain reveals Gram-negative diplococci. What is the most appropriate treatment?

Ceftriaxone. ***Ceftriaxone*** - The image shows **urethritis** (discharge from the urethra), and the Gram stain revealing **Gram-negative diplococci** is characteristic of **Neisseria gonorrhoeae**. - **Ceftriaxone** is the recommended first-line treatment for **gonorrhea**, often administered as a single intramuscular dose. *Azithromycin* - While often co-administered with ceftriaxone to cover potential **Chlamydia coinfection**, it is not the primary treatment for gonorrhea alone. - Azithromycin is the main treatment for uncomplicated **Chlamydia trachomatis** infections. *Doxycycline* - **Doxycycline** is a highly effective antibiotic for treating **Chlamydia trachomatis** infections and certain other bacterial STIs. - It is not the primary treatment for **gonorrhea** due to resistance concerns and preferred efficacy of cephalosporins. *Acyclovir* - **Acyclovir** is an antiviral medication used to treat infections caused by the **herpes simplex virus (HSV)**. - It has no activity against **bacterial infections** like gonorrhea, making it inappropriate for this presentation.

Q: A 25-year-old woman with HIV (CD4 count 320/μL) presents with vulvar ulceration for 3 weeks. Initial testing for HSV, syphilis, and chancroid is negative. Empiric treatment for these conditions does not improve the lesion. Biopsy shows a dense lymphoplasmacytic infiltrate with CMV inclusions. What is the most appropriate management?

Intravenous ganciclovir for 14-21 days. The biopsy showing **CMV inclusions** confirms **cytomegalovirus (CMV) infection** as the cause of the vulvar ulceration. **Ganciclovir** is the first-line antiviral treatment for serious CMV infections, especially in immunocompromised patients, and intravenous administration provides sufficient systemic efficacy. *Oral fluconazole for 14 days* - **Fluconazole** is an antifungal medication primarily used to treat candidiasis [1]. - It would be ineffective against **CMV**, which is a viral infection, and is not indicated for her current diagnosis. *Topical corticosteroids* - **Corticosteroids** are anti-inflammatory agents that could potentially worsen a viral infection by further suppressing the immune response [1]. - They do not address the underlying **CMV infection** and are therefore contraindicated as primary treatment for this condition. *Oral valacyclovir for 14 days* - **Valacyclovir** is an antiviral medication effective against **herpes simplex virus (HSV)** and **varicella-zoster virus (VZV)** [2]. - While initial HSV testing was negative, and valacyclovir is not effective against **CMV** [2].

Q: Which factor most strongly influences vertical transmission risk of hepatitis B from mother to infant?

Maternal HBeAg status. ***Maternal HBeAg status*** - A mother who is **HBeAg-positive** indicates high levels of ongoing **HBV replication** and viral load, leading to a significantly higher risk of vertical transmission (up to 90%) [1]. - The presence of **HBeAg** means the hepatitis B virus is actively replicating, making transmission readily possible during pregnancy and delivery [1]. *Breastfeeding* - **Breastfeeding** alone does not significantly increase the risk of hepatitis B transmission when the infant receives appropriate **immunoprophylaxis** at birth. - While HBV can be detected in breast milk, the risk of transmission through this route is considered **negligible** compared to in-utero or perinatal exposure. *Mode of delivery* - While there is some risk associated with both **vaginal** and **cesarean deliveries** due to exposure to maternal blood, the mode of delivery is not the strongest predictor of transmission. - The primary risk factor remains the mother's **viral load**, which is best indicated by HBeAg status, rather than how the baby is born [1]. *Gestational age at delivery* - **Prematurity** can potentially increase susceptibility to infection, but **gestational age** is not the primary determinant of hepatitis B vertical transmission risk. - The infectiousness of the mother (viral load and HBeAg status) is far more important than the infant's gestational age at delivery [1].

Q: A 28-year-old man presents with recurrent urethritis despite appropriate treatment for gonorrhea and chlamydia. NAAT tests for both are negative. He reports adherence to therapy and denies reexposure. What is the most appropriate next step?

Testing for Mycoplasma genitalium. ***Testing for Mycoplasma genitalium*** - **Mycoplasma genitalium** is a common cause of **non-gonococcal urethritis** that is often resistant to standard gonorrhea and chlamydia treatments. [1] - Given the persistent symptoms despite appropriate treatment and negative NAAT for gonorrhea and chlamydia, testing for this organism is the most logical next step [1]. *HIV testing* - While HIV can affect immune function and increase susceptibility to infections, it is not a direct cause of recurrent urethritis that would require this as the immediate next diagnostic step in this specific scenario. - There are no symptoms mentioned that would specifically point towards an acute HIV infection or AIDS-defining illness causing the recurrent urethritis. *Repeat treatment with higher-dose azithromycin* - This is not appropriate without a confirmed pathogen, as empirical treatment with higher doses can contribute to **antimicrobial resistance**. - The patient has already received appropriate treatment, and repeating it without knowing the cause may delay accurate diagnosis and effective management. *Urologic evaluation for structural abnormalities* - While structural abnormalities could cause recurrent urinary tract symptoms, they are a less common cause of recurrent infectious urethritis in a young, otherwise healthy male. - A urologic evaluation would typically be considered after infectious causes, especially common and treatable STIs like **Mycoplasma genitalium**, have been ruled out [1].

Q: A 38-year-old man with HIV (CD4 count 150/μL) presents with progressive perianal ulceration for 3 months. Multiple biopsies show granulomatous inflammation without organisms. PCR for HSV, dark field microscopy, and serological tests for syphilis are negative. He has received empiric treatment for HSV and syphilis without improvement. What is the most likely diagnosis?

Donovanosis (granuloma inguinale). ***Donovanosis (granuloma inguinale)*** - This diagnosis is strongly suggested by **progressive perianal ulceration** with **granulomatous inflammation** and the exclusion of other common causes, particularly in an immunocompromised patient. - The absence of organisms on routine biopsy, along with negative PCR for HSV and syphilis serology, points towards **Donovanosis**, caused by *Klebsiella granulomatis*, which requires special staining for **Donovan bodies** [1]. *Crohn's disease* - While Crohn's disease can cause perianal ulcerations and granulomas, the **rapid progression** and specific mention of an infectious workup strongly favor an infective etiology in this immunocompromised patient. - Absence of other typical gastrointestinal symptoms like abdominal pain, diarrhea, or weight loss makes Crohn's less likely. *Lymphogranuloma venereum* - Lymphogranuloma venereum (LGV) typically presents with **inguinal lymphadenopathy** (buboes) and initial transient ulcers, rather than progressive perianal ulceration with primary granulomatous inflammation on biopsy [1]. - While it can cause proctitis, the primary presentation described here is less typical for LGV. *Squamous cell carcinoma* - Although immunosuppression increases the risk of squamous cell carcinoma, a "progressive ulceration" with **granulomatous inflammation** described on biopsy is more characteristic of an infectious or inflammatory process than malignancy. - Malignant lesions would typically show **atypical cells** and **dysplasia** on biopsy, which is not mentioned here.

Question 1

Tuberculosis in HIV positive individuals is characterized by which of the following?

1. More frequent negative sputum smears.
2. More false–negative tuberculin test results.
3. More extra–pulmonary tuberculosis.
4. More cavitating lesions in lungs as shown by chest X-ray.

Select the correct answer using the code given below:

Accepted Answer

1, 2 and 3 only

Answer

1, 2, 3 and 4

Answer

1 and 2 only

Answer

3 and 4 only

Question 2

Which of the following is not a clinical feature of tetanus?

Accepted Answer

Loss of consciousness

Answer

Risus sardonicus

Answer

Respiratory failure

Answer

Opisthotonus

Question 3

At present, treatment is recommended for H. pylori in association with the following except:

Accepted Answer

Functional dyspepsia without alarm features

Answer

MALT lymphoma

Answer

Duodenal ulcer

Answer

Peptic ulcer disease

Question 4

Consider the following statements regarding Opportunistic post-splenectomy infections (OPSI):

1. Haemophilus influenzae, Neisseria meningitidis and Streptococcus pneumoniae are the most common causative agents
2. Risk is greatest in the patients who have undergone splenectomy for trauma
3. Risk is greatest within the first 2–3 years following splenectomy
4. Prophylactic vaccination should be done 2 weeks prior to elective splenectomy

Which of the statements given above are correct?

Accepted Answer

1, 2 and 3

Answer

1, 2 and 4

Answer

1, 3 and 4

Answer

2, 3 and 4

Question 5

Which one of the following statements is NOT correct regarding Pyogenic Liver Abscess?

Accepted Answer

Treatment is with oral antibiotics alone

Answer

It is more common in elderly, diabetics and immunocompromised patients

Answer

Streptococcus milleri and escherichia coli are the most common causative organisms

Answer

Anorexia, fever, malaise and right upper quadrant abdominal discomfort are the most common presenting features

Question 6

An adult man presents with the clinical condition shown in the image, and a Gram stain reveals Gram-negative diplococci. What is the most appropriate treatment?

Accepted Answer

Ceftriaxone

Answer

Azithromycin

Answer

Doxycycline

Answer

Acyclovir

Question 7

A 25-year-old woman with HIV (CD4 count 320/μL) presents with vulvar ulceration for 3 weeks. Initial testing for HSV, syphilis, and chancroid is negative. Empiric treatment for these conditions does not improve the lesion. Biopsy shows a dense lymphoplasmacytic infiltrate with CMV inclusions. What is the most appropriate management?

Accepted Answer

Intravenous ganciclovir for 14-21 days

Answer

Oral fluconazole for 14 days

Answer

Topical corticosteroids

Answer

Oral valacyclovir for 14 days

Question 8

Which factor most strongly influences vertical transmission risk of hepatitis B from mother to infant?

Accepted Answer

Maternal HBeAg status

Answer

Breastfeeding

Answer

Mode of delivery

Answer

Gestational age at delivery

Question 9

A 28-year-old man presents with recurrent urethritis despite appropriate treatment for gonorrhea and chlamydia. NAAT tests for both are negative. He reports adherence to therapy and denies reexposure. What is the most appropriate next step?

Accepted Answer

Testing for Mycoplasma genitalium

Answer

HIV testing

Answer

Repeat treatment with higher-dose azithromycin

Answer

Urologic evaluation for structural abnormalities

Question 10

A 38-year-old man with HIV (CD4 count 150/μL) presents with progressive perianal ulceration for 3 months. Multiple biopsies show granulomatous inflammation without organisms. PCR for HSV, dark field microscopy, and serological tests for syphilis are negative. He has received empiric treatment for HSV and syphilis without improvement. What is the most likely diagnosis?

Accepted Answer

Donovanosis (granuloma inguinale)

Answer

Crohn's disease

Answer

Lymphogranuloma venereum

Answer

Squamous cell carcinoma

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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