Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 381: Which of the following is given as a part of the therapy for a child with severe COVID?

A. Corticosteroids (Correct Answer)
B. Ivermectin
C. Remdesivir
D. All of the options

Explanation: ***Correct: Corticosteroids*** - **Corticosteroids** (specifically **dexamethasone**) are the **most established evidence-based therapy** for severe COVID-19 in children requiring oxygen support or mechanical ventilation - They reduce **mortality** by suppressing the hyperinflammatory response and cytokine storm associated with severe COVID-19 - Recommended by **WHO, NIH, and Indian Academy of Pediatrics (IAP)** for hospitalized children with severe COVID-19 requiring supplemental oxygen - The **RECOVERY trial** demonstrated significant mortality reduction in patients receiving oxygen therapy *Incorrect: Ivermectin* - **Ivermectin** is **NOT recommended** for COVID-19 treatment by WHO, FDA, NIH, or IAP - Multiple large randomized controlled trials (including TOGETHER trial) showed **no significant benefit** in preventing severe disease, hospitalization, or mortality - Initial in-vitro activity did not translate to clinical efficacy - Not part of standard therapy for severe COVID-19 in children *Incorrect: Remdesivir* - **Remdesivir** is an antiviral that may shorten recovery time in hospitalized adults - Evidence in **pediatric patients** is limited compared to adults - While used in some hospitalized patients, it is **not as universally recommended** as corticosteroids for severe disease - The **primary established therapy** for severe COVID-19 remains corticosteroids *Incorrect: All of the options* - Only **corticosteroids** represent standard, evidence-based therapy for severe pediatric COVID-19 - Ivermectin lacks efficacy evidence and is not recommended - The question asks what "is given as part of therapy" - corticosteroids are the definitive answer

Question 382: Which of the following is a true statement about congenital CMV infection?

A. About 20-30% of the infections are symptomatic
B. If mother is IgG positive for CMV prior to conception, the child is less likely to develop severe infection (Correct Answer)
C. Triad of SNHL, periventricular calcification and enamel hypoplasia
D. Most children asymptomatic at birth can develop conductive hearing loss later in life

Explanation: ***If mother is IgG positive for CMV prior to conception, the child is less likely to develop severe infection*** - A mother who is **IgG positive for CMV prior to conception** has pre-existing immunity, which provides significant protection to the fetus. - While maternal immunity doesn't completely prevent transmission (reactivation/reinfection can occur), it **substantially reduces the risk of severe congenital CMV infection** and symptomatic disease in the infant compared to primary maternal infection during pregnancy. - Primary maternal CMV infection during pregnancy carries a **30-40% transmission rate** with higher risk of severe disease, whereas non-primary infection (in seropositive mothers) has much lower transmission rates and severity. *About 20-30% of the infections are symptomatic* - The majority of congenital CMV infections are **asymptomatic at birth**, with only about **10-15% of infected infants exhibiting symptoms**. - 20-30% is an **overestimation of symptomatic cases** at birth. *Triad of SNHL, periventricular calcification and enamel hypoplasia* - The classical features of congenital CMV infection include **sensorineural hearing loss (SNHL)**, **periventricular calcifications**, and **chorioretinitis**, not enamel hypoplasia. - **Enamel hypoplasia** is more commonly associated with conditions like congenital syphilis, fluorosis, or severe childhood illnesses, not CMV. - Other features include microcephaly, hepatosplenomegaly, thrombocytopenia, and petechiae. *Most children asymptomatic at birth can develop conductive hearing loss later in life* - Children with congenital CMV infection (even asymptomatic) are at risk for **sensorineural hearing loss (SNHL)**, not conductive hearing loss. - SNHL is the most common long-term sequela of congenital CMV, affecting up to **10-15% of asymptomatic cases**, and can be **progressive or delayed in onset**.

Question 383: A 6-year-old child is brought with high fever with rigors for 5 days with pain in right hypochondrium. On examination, the patient is anicteric and tenderness is noted in right upper quadrant. What is the best investigation for this case?

A. SGOT/LFT
B. CECT
C. Serology
D. USG (Correct Answer)

Explanation: ***USG*** - A **ultrasound** is the preferred initial investigation, especially in children, for evaluating abdominal pain in the **right hypochondrium** with fever. - It can effectively identify common causes like **cholecystitis**, **hepatitis**, or **liver abscess**, which fit the clinical presentation. *SGOT/LFT* - **Liver function tests (LFTs)** like SGOT/AST and SGPT/ALT provide information about liver inflammation or damage but do not help localize the pathology. - They are useful for assessing liver function but are not the primary diagnostic tool to identify the cause of the pain or fever. *CECT* - **Contrast-enhanced computed tomography (CECT)** is a more advanced imaging technique, often used after initial screening or when ultrasound findings are inconclusive. - It involves radiation exposure and contrast risks, making it less suitable as a first-line investigation for a child with these symptoms. *Serology* - **Serological tests** detect antibodies or antigens related to specific infections (e.g., viral hepatitis) but do not provide immediate anatomical information. - While they can confirm an infectious cause, they cannot identify the source of the pain or rule out other non-infectious pathologies immediately.

Question 384: Most common cause of bacterial meningitis in post-neonatal period:

A. Mycobacterium tuberculosis
B. Staphylococcus aureus
C. Streptococcus pneumoniae (Correct Answer)
D. Klebsiella

Explanation: ***Streptococcus pneumoniae*** - *S. pneumoniae* is the most common cause of **bacterial meningitis** in the post-neonatal period (1 month to 1 year of age), particularly in regions with high vaccination rates against Hib. - Its polysaccharide capsule and ability to evade the immune system contribute to its virulence in causing **central nervous system infections**. - Accounts for approximately 40-50% of bacterial meningitis cases in this age group. *Mycobacterium tuberculosis* - While it can cause **tuberculous meningitis**, this is a less common form of meningitis, typically with a more **insidious onset** and often associated with immunosuppression or endemic areas. - Represents a chronic form of meningitis rather than acute bacterial meningitis. *Staphylococcus aureus* - *S. aureus* meningitis typically occurs in specific contexts such as **post-neurosurgery**, following head trauma, or in patients with indwelling catheters or bacteremia. - It is not the most frequent pathogen in community-acquired meningitis in infants. *Klebsiella* - **Klebsiella pneumoniae** can cause meningitis, especially in **neonates** (first 28 days of life), immunocompromised individuals, or patients with healthcare-associated infections. - However, it is not the most common cause of meningitis in the post-neonatal period.

Question 385: Sixth disease is?

A. Erythema nodosum
B. Erythema marginatum
C. Erythema Infectiosum
D. Exanthema subitum (Correct Answer)

Explanation: ***Exanthema subitum*** - Exanthema subitum, also known as **Roseola infantum** or **sixth disease**, is a common childhood illness caused by human herpesvirus 6 (HHV-6) or less commonly HHV-7. - It is characterized by **3-5 days of high fever** followed by the abrupt appearance of a **maculopapular rash** once the fever subsides. *Erythema nodosum* - **Erythema nodosum** presents as tender, red nodules, typically on the shins, and is a type of **panniculitis** (inflammation of subcutaneous fat). - It is often associated with systemic diseases, infections (e.g., strep throat, tuberculosis), drugs, or inflammatory bowel disease, rather than being a primary childhood viral exanthem. *Erythema marginatum* - **Erythema marginatum** is a rare, transient, and non-pruritic rash with **serpiginous (snake-like) borders** that is a specific hallmark of **acute rheumatic fever**. - It is not a generalized viral exanthem and does not follow a typical febrile phase like sixth disease. *Erythema Infectiosum* - **Erythema infectiosum**, also known as **fifth disease**, is caused by **parvovirus B19** and is characterized by a "slapped cheek" rash on the face followed by a lacy rash on the trunk and extremities. - While it's a common childhood exanthem, it's distinct from sixth disease in its causative agent and characteristic rash pattern.

Question 386: A 6-year-old child presents with hepatosplenomegaly and generalized lymphadenopathy along with fever. The child developed a rash after being administered ampicillin. What could be the possible diagnosis?

A. Kawasaki disease
B. Scarlet fever
C. Infectious mononucleosis (Correct Answer)
D. HIV infection

Explanation: ***Infectious mononucleosis*** - The combination of **hepatosplenomegaly**, **generalized lymphadenopathy**, and fever in a child is highly suggestive of infectious mononucleosis, typically caused by the **Epstein-Barr virus (EBV)**. - A characteristic feature is the development of a **maculopapular rash** following the administration of ampicillin or amoxicillin. *Kawasaki disease* - Characterized by **fever**, generalized rash, lymphadenopathy, and mucocutaneous inflammation, but typically does not involve significant **hepatosplenomegaly**. - The rash in Kawasaki disease is not typically triggered by **ampicillin**. *Scarlet fever* - Caused by a **Streptococcus pyogenes** infection and presents with a characteristic **sandpaper-like rash**, **strawberry tongue**, and fever. - It usually does not involve significant **hepatosplenomegaly** or a rash specifically induced by ampicillin. *HIV infection* - While HIV can cause **generalized lymphadenopathy** and **hepatosplenomegaly**, especially in children, the sudden onset of a rash specifically after ampicillin administration is not a hallmark of acute or chronic HIV infection. - Other opportunistic infections and **growth failure** would likely be present in advanced HIV.

Question 387: Koplik spots are seen in?

A. Rubella
B. Mumps
C. Varicella
D. Measles (Correct Answer)

Explanation: ***Measles*** - **Koplik spots** are pathognomonic rash that appears as small, white spots with a bluish-white center on an erythematous base on the **buccal mucosa** opposite the second molars. - They typically appear 2-3 days before the onset of the characteristic maculopapular rash, during the **prodromal phase** of measles (rubeola). *Rubella* - Rubella, or **German measles**, presents with a milder rash, **lymphadenopathy**, and mild fever. - It does not cause Koplik spots; instead, **Forchheimer spots** (petechiae on the soft palate) may be seen, but these are less specific. *Mumps* - Mumps is characterized primarily by **parotitis** (swelling of the salivary glands), fever, and headache. - It does not present with Koplik spots or any characteristic oral mucosal lesions. *Varicella* - Varicella, or **chickenpox**, is characterized by a **vesicular rash** that progresses from macules to papules to vesicles to crusts, appearing in crops. - It does not involve Koplik spots; the rash is typically generalized and pruritic.

Question 388: Most common cause of post-measles death?

A. SSPE
B. Pneumonia (Correct Answer)
C. Myocarditis
D. Diarrhea

Explanation: ***Pneumonia*** - **Pneumonia**, particularly secondary bacterial pneumonia, is the **most common cause of death** in children following a measles infection. - Measles causes **immune suppression** and damage to the respiratory epithelium, making individuals vulnerable to severe respiratory infections. *SSPE* - **Subacute sclerosing panencephalitis (SSPE)** is a rare, fatal, late complication of measles, occurring years after the initial infection. - While always fatal, its rarity means it is not the most common cause of overall measles-related mortality. *Myocarditis* - **Myocarditis**, inflammation of the heart muscle, can be a rare complication of measles, but it is not the leading cause of death. - Cardiac complications are less frequently observed as the primary cause of death compared to respiratory infections. *Diarrhea* - **Diarrhea** is a common complication of measles, especially in malnourished children, and can contribute to mortality due to **dehydration** and electrolyte imbalances. - However, severe respiratory complications like pneumonia are still responsible for a higher proportion of measles-related deaths.

Question 389: According to WHO clinical staging of HIV in children oral hairy leukoplakia belongs to which clinical stages?

A. Clinical stage 1
B. Clinical stage 3
C. Clinical stage 4
D. Clinical stage 2 (Correct Answer)

Explanation: ***Clinical stage 2*** - **Oral hairy leukoplakia** is classified under WHO clinical stage 2 for HIV infection, representing mild symptomatic disease with moderate immune compromise. - Stage 2 includes conditions such as **angular cheilitis**, **papular pruritic eruptions**, **recurrent oral ulcerations**, **herpes zoster**, **lineal gingival erythema**, and **recurrent upper respiratory tract infections**. - **Note:** Oral hairy leukoplakia is **rare in children** and is more commonly seen in adults with HIV; it is caused by **Epstein-Barr virus** reactivation. *Clinical stage 1* - This stage includes **asymptomatic** HIV infection or **persistent generalized lymphadenopathy**. - Stage 1 represents minimal or no immune compromise with no clinical manifestations requiring intervention. *Clinical stage 3* - Clinical stage 3 represents **advanced symptomatic disease** with conditions like **unexplained severe malnutrition**, **unexplained persistent diarrhea**, **oral candidiasis**, **pulmonary tuberculosis**, and **severe recurrent bacterial pneumonia**. - These conditions indicate more severe immunodeficiency than oral hairy leukoplakia. *Clinical stage 4* - Clinical stage 4 represents **severe HIV disease** with AIDS-defining illnesses such as **Pneumocystis jirovecii pneumonia**, **extrapulmonary tuberculosis**, **Kaposi's sarcoma**, **HIV encephalopathy**, **CMV retinitis**, and **disseminated mycobacterial infections**. - Stage 4 conditions are life-threatening and indicate severe immunosuppression.

Question 390: A child with pyoderma becomes toxic and presents with respiratory distress. His chest radiograph shows patchy areas of consolidation and multiple bilateral thin-walled air containing cysts. The most likely etiological agent in this case is –

A. Mycobacterium tuberculosis
B. Pneumocystis jirovecii
C. Staphylococcus aureus (Correct Answer)
D. Mycobacterium avium intracellulare

Explanation: ***Staphylococcus aureus*** - *S. aureus* is a common cause of **severe pyoderma** and can lead to **systemic toxicity** and **hematogenous spread** to the lungs. - The characteristic lung findings of **patchy consolidation** and **multiple thin-walled air-containing cysts** (pneumatoceles) are highly suggestive of *S. aureus* pneumonia, particularly in children. *Mycobacterium tuberculosis* - While *M. tuberculosis* can cause lung consolidation, it typically presents with **granulomatous inflammation** and is less likely to produce **multiple thin-walled cysts** rapidly in an acute, toxic presentation. - Pulmonary tuberculosis often has a more **insidious onset** and may be associated with risk factors like immunocompromise or exposure. *Pneumocystis jirovecii* - This pathogen primarily causes pneumonia in **immunocompromised individuals**, such as those with HIV, and is less common in an otherwise healthy child with pyoderma. - Chest radiographs typically show **diffuse interstitial infiltrates**, not distinct patchy consolidation or thin-walled cysts. *Mycobacterium avium intracellulare* - Like *P. jirovecii*, *M. avium intracellulare* (MAC) usually affects **immunocompromised individuals** or those with pre-existing lung disease. - MAC lung disease typically presents as **nodular or cavitary lesions** or diffuse infiltrates, not the characteristic acute cyst formation seen in this case.

Practice by Chapter

Vaccine-Preventable Diseases

Practice Questions

Immunization Schedule

Practice Questions

Common Childhood Infections

Practice Questions

Pediatric HIV

Practice Questions

Congenital Infections

Practice Questions

Fever in Infants and Children

Practice Questions

Meningitis and Encephalitis

Practice Questions

Respiratory Tract Infections

Practice Questions

Gastrointestinal Infections

Practice Questions

Parasitic Infections

Practice Questions

Tuberculosis in Children

Practice Questions

Opportunistic Infections

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free