Infectious Diseases — MCQs

An 8-year-old boy from an impoverished inner-city area has never been vaccinated appropriately. He develops fever, cough, and coryza. The next day, blue white spots develop on the buccal mucosa. On the third day, an erythematous, nonpruritic maculopapular rash develops on the face and spreads over the entire body. Which of the following is the most likely complication?

Q456

Symptomatic neonatal CNS involvement is most commonly seen in which group of congenital intrauterine infections?

Q457

Child with generalized petechiae. CSF shows gram-negative diplococci. Treatment -

Q458

Which of the following is Not characteristic of congenital Syphilis?

Q459

Best method to diagnose HIV in an infant?

Q460

Reye's syndrome in children is commonly associated with aspirin use during which type of infection?

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 451: Which of the following is true about Diphtheria EXCEPT:

A. Faucial diphtheria is more dangerous than laryngeal diphtheria (Correct Answer)
B. Laryngeal diphtheria mandates tracheotomy
C. Myocarditis may be a complication
D. Child is more toxic with faucial diphtheria

Explanation: ***Faucial diphtheria is more dangerous than laryngeal diphtheria*** - This statement is **FALSE** and is the correct answer to this EXCEPT question. - **Laryngeal diphtheria** is generally considered more immediately dangerous than faucial diphtheria due to the risk of **acute airway obstruction** that can rapidly lead to asphyxiation and death. - While faucial diphtheria can lead to significant systemic toxin absorption and complications, the direct mechanical threat to the airway in laryngeal involvement poses a more acute life-threatening risk. *Laryngeal diphtheria mandates tracheotomy* - This statement is also **not entirely true** but is more accurate than option A. - **Tracheotomy** is reserved for severe cases with impending or actual airway obstruction, not mandated in all laryngeal diphtheria cases. - Modern management includes close monitoring, intubation when needed, and antitoxin therapy first. *Child is more toxic with faucial diphtheria* - This is **partially true** as faucial diphtheria typically involves larger surface area for toxin absorption. - However, the degree of toxicity depends on multiple factors including the extent of membrane formation, timing of antitoxin administration, and immunization status. - Both faucial and laryngeal types can cause severe systemic toxicity. *Myocarditis may be a complication* - This statement is **TRUE**. - **Myocarditis** is a well-recognized and potentially fatal complication of diphtheria caused by the **diphtheria exotoxin** directly damaging myocardial cells. - It typically occurs 1-2 weeks after infection and can lead to **cardiac arrhythmias, heart block, and heart failure**. - Myocarditis is one of the major causes of mortality in diphtheria cases.

Question 452: In a 3-year-old child, the most common cause of hepatitis is:

A. Perinatal
B. Pin prick
C. Saliva exchange
D. Hepatitis A virus infection (Correct Answer)

Explanation: ***Hepatitis A virus infection*** - **Hepatitis A virus (HAV)** is highly contagious and spreads primarily through the **fecal-oral route**, making it common in daycare settings or among young children. - In children, HAV infection is often **asymptomatic** or presents with mild, non-specific symptoms, but it is a frequent cause of acute hepatitis in this age group. *Perinatal* - **Perinatal transmission** typically refers to infections transmitted from mother to child around the time of birth, which is a common route for **Hepatitis B** and **Hepatitis C**, not generally HAV. - While possible, perinatal transmission is not the most common cause of hepatitis in a 3-year-old, as exposure usually occurs after birth in the general environment. *Pin prick* - **Pin prick injuries** or exposures to contaminated needles are routes for **blood-borne viruses** like **Hepatitis B** and **Hepatitis C**. - This mode of transmission is rare and atypical for a 3-year-old child and is not the primary route for the most common cause of hepatitis in this age group. *Saliva exchange* - While some viruses can be transmitted through **saliva exchange**, **Hepatitis A** is primarily transmitted via the **fecal-oral route**, not typically through saliva. - **Saliva exchange** is not a common or significant mode of transmission for hepatitis viruses that cause acute hepatitis in young children.

Question 453: For the prevention of parent to child transmission of HIV, the NACO's recommendation is to give -

A. Zidovudine monotherapy to mother during pregnancy and labor only
B. Efavirenz monotherapy to mother throughout pregnancy and breastfeeding
C. Nevirapine single dose to mother in labor and single dose to newborn
D. Tenofovir + Lamivudine + Dolutegravir (TLD regimen) to mother and Nevirapine syrup to newborn for 6 weeks (Correct Answer)

Explanation: ***Tenofovir + Lamivudine + Dolutegravir (TLD regimen) to mother and Nevirapine syrup to newborn for 6 weeks*** - **TLD regimen** (Tenofovir + Lamivudine + Dolutegravir) is the current **first-line cART** recommended by NACO since 2021 for pregnant HIV-positive women, providing superior **viral suppression** and reduced transmission risk. - **Nevirapine syrup for 6 weeks** starting within 6-12 hours of birth is the standard **neonatal prophylaxis** per NACO guidelines, offering comprehensive protection against mother-to-child transmission. *Zidovudine monotherapy to mother during pregnancy and labor only* - **Monotherapy approaches** are outdated and associated with higher **failure rates** and increased risk of **drug resistance** development. - Lacks **comprehensive neonatal protection** component, which is essential for effective PMTCT strategy according to current guidelines. *Efavirenz monotherapy to mother throughout pregnancy and breastfeeding* - **Single-drug therapy** is inadequate as it lacks the **synergistic effects** of combination therapy and has higher rates of treatment failure. - Missing the critical **neonatal prophylaxis component** and other essential drugs (Tenofovir, Lamivudine) that provide comprehensive viral suppression. *Nevirapine single dose to mother in labor and single dose to newborn* - This represents an **older PMTCT regimen** that has been replaced due to **high rates of resistance** development and inferior efficacy. - **Single-dose approaches** provide suboptimal protection compared to **combination cART therapy** and the standard **6-week neonatal prophylaxis** now recommended by current NACO guidelines.

Question 454: Which of the following statements concerning sensorineural hearing loss in children with bacterial meningitis are TRUE?

A. It occurs rarely (less than 5% of cases)
B. Its onset often is late in the clinical course, after discontinuation of antimicrobial therapy
C. Prompt institution of antimicrobial therapy appears not to influence the incidence (Correct Answer)
D. It occurs more commonly when Haemophilus influenza type B rather than Streptococcus pneumoniae is the causative organism of the meningitis

Explanation: ***Prompt institution of antimicrobial therapy appears not to influence the incidence*** - While prompt antibiotic therapy is crucial for overall outcomes in **bacterial meningitis**, studies have shown it does not consistently reduce the risk or incidence of **sensorineural hearing loss**. - **Hearing loss** often results from direct damage to the cochlea or auditory nerve by inflammatory mediators and bacterial toxins early in the disease process, which may occur before antibiotics can fully mitigate the damage. *It occurs rarely (less than 5% of cases)* - **Sensorineural hearing loss** is a common and significant complication of **bacterial meningitis**, occurring in approximately **10-30%** of pediatric cases, not rarely. - This high incidence makes it a leading cause of acquired **hearing impairment** in children. *Its onset often is late in the clinical course, after discontinuation of antimicrobial therapy* - The onset of **sensorineural hearing loss** typically occurs **early** in the disease course, often during the acute phase of meningitis. - It results from direct damage to the **cochlea** or auditory nerve due to intense inflammation and the toxic effects of bacteria. *It occurs more commonly when Haemophilus influenza type B rather than Streptococcus pneumoniae is the causative organism of the meningitis* - Historically, **Haemophilus influenzae type B (Hib)** was a major cause of hearing loss following meningitis, but the introduction of the Hib vaccine has significantly reduced its incidence. - Currently, **Streptococcus pneumoniae (pneumococcus)** is more commonly associated with **sensorineural hearing loss** in bacterial meningitis cases.

Question 455: An 8-year-old boy from an impoverished inner-city area has never been vaccinated appropriately. He develops fever, cough, and coryza. The next day, blue white spots develop on the buccal mucosa. On the third day, an erythematous, nonpruritic maculopapular rash develops on the face and spreads over the entire body. Which of the following is the most likely complication?

A. encephalitis
B. bronchitis
C. otitis media
D. pneumonia (Correct Answer)

Explanation: ***Pneumonia*** - This scenario describes **measles** (rubeola) with the classic triad of fever, cough, and coryza (the **3 Cs**), along with pathognomonic **Koplik spots** (blue-white spots on buccal mucosa) and the characteristic **maculopapular rash** spreading cephalocaudally from the face. - **Pneumonia** is the **most common serious complication** of measles, occurring in approximately **1-6% of cases**, and is the **leading cause of measles-related mortality** in children. - It can be either **viral pneumonia** (direct measles virus infection) or **secondary bacterial pneumonia** (especially *Streptococcus pneumoniae*, *Staphylococcus aureus*, *Haemophilus influenzae*). - This is particularly common in **unvaccinated, malnourished, and immunocompromised children** from impoverished areas, as described in this case. *Otitis media* - **Otitis media** is a common complication of measles, occurring in approximately **5-9% of cases**. - While frequent, it is **less common than pneumonia** and is generally less severe in terms of mortality risk. - It typically presents with ear pain and can lead to hearing complications if untreated. *Encephalitis* - **Measles encephalitis** is a rare but severe complication, occurring in approximately **1 in 1000 cases** (0.1%). - It typically develops **1-2 weeks after rash onset**, presenting with fever, headache, seizures, altered consciousness, and neurological deficits. - While serious with significant mortality and morbidity, it is **much less common** than pneumonia. *Bronchitis* - **Bronchitis** (cough, chest congestion) is typically part of the **initial prodromal phase** of measles itself rather than a distinct complication. - The respiratory symptoms (cough, coryza) are manifestations of the primary measles infection, not secondary complications.

Question 456: Symptomatic neonatal CNS involvement is most commonly seen in which group of congenital intrauterine infections?

A. Rubella and toxoplasmosis
B. CMV and syphilis
C. Rubella and HSV
D. CMV and toxoplasmosis (Correct Answer)

Explanation: ***CMV and toxoplasmosis*** - Both **cytomegalovirus (CMV)** and **Toxoplasma gondii** are well-known causes of congenital infections that frequently lead to significant and symptomatic central nervous system (CNS) involvement in neonates. - Congenital CMV can cause **microcephaly**, **periventricular calcifications**, **hearing loss**, and developmental delay, while congenital toxoplasmosis can result in **hydrocephalus**, **intracranial calcifications**, **chorioretinitis**, and seizures. *Rubella and toxoplasmosis* - While **toxoplasmosis** causes significant CNS involvement, **congenital rubella syndrome** typically presents with cataracts, heart defects (e.g., patent ductus arteriosus), and hearing loss, with CNS involvement being less consistently severe or frequently symptomatic in the immediate neonatal period compared to CMV or toxoplasmosis. - Although rubella can cause **encephalitis** or **meningoencephalitis**, these are not as common or consistently severe as the direct destructive CNS lesions seen with CMV or toxoplasmosis. *CMV and syphilis* - **CMV** is a major cause of neonatal CNS symptoms. However, **congenital syphilis** primarily affects bones, skin, and mucous membranes (e.g., "snuffles"), with CNS involvement typically presenting as **meningitis**, **hydrocephalus**, or neurodevelopmental delays, but often not as overtly symptomatic in the immediate neonatal period as CMV or toxoplasmosis. - While syphilis can cause neurosyphilis, the spectrum and severity of immediate symptomatic CNS involvement are distinct from the widespread calcifications and structural abnormalities seen with CMV or toxoplasmosis. *Rubella and HSV* - **Rubella** primarily causes classic congenital defects in eyes, ears, and heart, with CNS effects being less common and severe. - **Congenital herpes simplex virus (HSV)** infection, while causing severe CNS disease (e.g., encephalitis) when disseminated, is relatively rare overall compared to CMV and toxoplasmosis, and often presents with skin, eye, and mouth lesions first.

Question 457: Child with generalized petechiae. CSF shows gram-negative diplococci. Treatment -

A. IV Penicillin G
B. Oral Penicillin V
C. IV Ceftriaxone (Correct Answer)
D. IV Cefotaxime

Explanation: ***IV Ceftriaxone*** - The presence of **generalized petechiae** and **gram-negative diplococci** in the CSF strongly suggests **meningococcal meningitis**, which is a severe infection requiring prompt and effective antibiotic treatment. - **Ceftriaxone** is a third-generation cephalosporin that has excellent penetration into the CSF and is a first-line treatment for bacterial meningitis caused by *Neisseria meningitidis*. *IV Penicillin G* - While **Penicillin G** can be effective against penicillin-susceptible strains of *Neisseria meningitidis*, there is increasing concern about penicillin resistance. - **Ceftriaxone** is generally preferred empirically due to its broader coverage and reliable efficacy against penicillin-resistant strains. *IV Penicillin V* - **Penicillin V** is an oral penicillin, and it is not suitable for the treatment of severe, invasive infections like **meningitis** due to inadequate systemic and CSF concentrations. - It is typically used for less severe infections like pharyngitis. *IV Cefotaxime* - **Cefotaxime** is also a third-generation cephalosporin with good CSF penetration and is an effective treatment for bacterial meningitis. - However, in many guidelines, **ceftriaxone** is often listed as the preferred agent due to its longer half-life, allowing for once-daily or twice-daily dosing, which is more convenient.

Question 458: Which of the following is Not characteristic of congenital Syphilis?

A. Interstitial keratitis
B. Mulberry molars
C. Ghon complex (Correct Answer)
D. Notched incisors

Explanation: ***Ghon complex*** - A **Ghon complex** (primary tubercular complex) is a characteristic feature of **primary tuberculosis**, not congenital syphilis. - It consists of a **calcified lesion** in the lung periphery (Ghon focus) and associated hilar lymph node calcification. - This represents a healed primary TB infection. *Interstitial keratitis* - **Interstitial keratitis** is a classic manifestation of **late congenital syphilis**, often appearing around puberty. - It involves inflammation of the **cornea, leading to photophobia and potentially blindness** if untreated. - Part of **Hutchinson's triad** (interstitial keratitis, Hutchinson's teeth, eighth nerve deafness). *Mulberry molars* - **Mulberry molars** (or Moon's molars) are a dental anomaly seen in **congenital syphilis**, characterized by irregularly shaped first molars with multiple, poorly formed cusps. - This is part of the **dental stigmata** of the disease. *Notched incisors* - **Notched incisors** (Hutchinson's teeth) are another pathognomonic sign of **congenital syphilis**. - They are characterized by **peg-shaped, widely spaced upper central incisors** with a crescent-shaped notch on the biting surface. - Also part of **Hutchinson's triad**.

Question 459: Best method to diagnose HIV in an infant?

A. ELISA
B. PCR (Correct Answer)
C. Western blot
D. All of the options

Explanation: ***PCR*** - **Polymerase Chain Reaction (PCR)** detects **HIV nucleic acids** (DNA or RNA) directly, which is crucial for infants because maternal antibodies can persist for up to 18 months, interfering with antibody-based tests. - PCR allows for early diagnosis, often within the first few weeks or months of life, facilitating timely intervention. *ELISA* - **Enzyme-linked immunosorbent assay (ELISA)** detects HIV antibodies. - In infants, ELISA can be misleading due to the presence of **maternal HIV antibodies** transferred across the placenta, making it unreliable for diagnosing active infection. *Western blot* - **Western blot** is used to confirm positive ELISA results in adults by detecting specific HIV proteins. - Like ELISA, it relies on the detection of **antibodies** and is therefore not reliable in infants due to maternally transmitted antibodies. *All of the options* - This option is incorrect because **ELISA** and **Western blot** are antibody-based tests that are unreliable in infants due to the presence of **maternal antibodies**. - Only **PCR** directly detects the virus itself, making it the preferred diagnostic method in this age group.

Question 460: Reye's syndrome in children is commonly associated with aspirin use during which type of infection?

A. Varicella (Chickenpox)
B. Influenza virus (Correct Answer)
C. HIV
D. Measles virus

Explanation: ***Influenza virus*** - Reye's syndrome is a rare but severe condition characterized by **acute encephalopathy and fatty liver infiltration** that predominantly affects children recovering from viral infections - **Aspirin use during influenza** is one of the two most strongly documented associations with Reye's syndrome, leading to contraindication of aspirin in children with febrile illnesses - The incidence of Reye's syndrome dropped dramatically after public health warnings against aspirin use in children with influenza-like illnesses *Varicella (Chickenpox)* - Varicella is the **other major viral infection** strongly associated with Reye's syndrome when aspirin is used - Both influenza and varicella are considered the two primary precipitating viral infections - In competitive exam context, when both are options, understanding the equal significance is important, though influenza is often cited first in classical teaching *HIV* - **HIV is a chronic infection** and not an acute febrile viral illness where aspirin would typically be used for symptomatic relief - Reye's syndrome is specifically associated with **acute viral illnesses** (influenza and varicella) where aspirin might be administered for fever control - No established association between HIV infection and Reye's syndrome *Measles virus* - While measles is an acute viral infection, the **documented association with Reye's syndrome is significantly weaker** compared to influenza and varicella - The major contraindication for aspirin in pediatric febrile illness specifically emphasizes **influenza and varicella** - Not considered one of the primary precipitating infections for Reye's syndrome

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

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