Infectious Diseases — MCQs

A 5-year-old previously healthy child is taken from his day care to the pediatrician because his mother is concerned that the child has been fussy for the past few days and now has a rash on his face and torso. The mother also says the boy told her his head hurts, and she thinks he may have a low-grade fever. On examination the child is afebrile and not ill-appearing. He has a rash extending over his entire body except for the palms and soles. The infectious agent causing this disease can lead to what complication in immunocompromised hosts?

Q475

In a rural clinic, a 3-year-old girl child is brought by her mother and is emaciated. Her hemoglobin was 5 g/dL. The girl also has edema over her knees and ankles with discrete rash on her knees, ankles and elbows. The most likely worm infestation causing these manifestations is:

Q476

Congenital rubella syndrome is associated with:

Q477

Congenital Rubella syndrome may have the following clinical features, except

Q478

A 30 month old deaf boy whose development is slower than normal is being followed for congenital cytomegalovirus (CMV) infection in your clinic.The child's mother is pregnant again and is worried about her new baby. Which of the following is true?

Q479

Most common organism causing meningitis in a 1 year old child -

Q480

True about childhood tuberculosis:

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 471: 3 year old sister of a neonate is suffering from pertussis, which has been documented by isolation and culture of the organism. The mother received the pertussis vaccine during pregnancy. Most appropriate statement regarding this clinical situation is -

A. DPT vaccine is recommended for the elder child
B. Azithromycin prophylaxis is indicated in the neonate (Correct Answer)
C. Hyperimmune globulin is indicated for the neonate
D. The neonate is protected due to maternal vaccination

Explanation: ***Azithromycin prophylaxis is indicated in the neonate*** - Neonates are highly vulnerable to **severe pertussis**, which can be life-threatening, making **post-exposure prophylaxis** crucial. - **Azithromycin** is the preferred macrolide antibiotic for pertussis prophylaxis and treatment in neonates, as it has better tolerability and a shorter treatment course compared to erythromycin. - **Erythromycin** carries a risk of infantile hypertrophic pyloric stenosis in infants <1 month old, making azithromycin the safer choice. *DPT vaccine is recommended for the elder child* - The 3-year-old already has pertussis, so vaccination at this point would not alter the course of her current illness, as the vaccine's purpose is **prevention**, not treatment. - While DPT vaccination is generally recommended for children, it's not the correct immediate action for a child actively suffering from **documented pertussis**. *Hyperimmune globulin is indicated for the neonate* - **Pertussis immune globulin** is not routinely recommended for pertussis prophylaxis or treatment due to insufficient evidence of its efficacy. - **Antibiotic prophylaxis** with a macrolide is the standard of care for exposed susceptible individuals, especially neonates. *The neonate is protected due to maternal vaccination* - While maternal pertussis vaccination during pregnancy does confer some **passive immunity** to the neonate, it might not offer complete protection, especially against close exposure to an infected sibling. - Given the severe risk of pertussis in neonates, **antibiotic prophylaxis** is still recommended as an extra layer of protection even with maternal antibodies.

Question 472: In a 6 months old baby, floppy infant syndrome is seen commonly due to infection with ?

A. Clostridium Botulinum (Correct Answer)
B. Clostridium welchii
C. Clostridium septicum
D. Clostridium tetani

Explanation: ***Clostridium Botulinum*** - **Infant botulism** is caused by the ingestion of **_Clostridium botulinum_ spores**, which colonize the infant's immature gut and produce neurotoxins. - The classic presentation is **floppy infant syndrome**, characterized by **hypotonia**, **weakness**, feeding difficulties, and constipation. *Clostridium welchii* - This is an outdated name for **_Clostridium perfringens_**, which is primarily associated with **food poisoning** and **gas gangrene**. - It does not cause floppy infant syndrome. *Clostridium septicum* - **_Clostridium septicum_** is known to cause **spontaneous gas gangrene** and is often associated with neutropenic enterocolitis (typhlitis). - It is not a cause of floppy infant syndrome. *Clostridium tetani* - **_Clostridium tetani_** produces **tetanospasmin**, a neurotoxin that causes **tetanus**, characterized by muscle spasms and rigidity (lockjaw). - It does not cause the flaccid paralysis seen in floppy infant syndrome.

Question 473: Resistant plasmodium falciparum malaria in the pediatric age group should be treated with -

A. Tetracycline
B. Artemether-lumefantrine (Correct Answer)
C. Clindamycin
D. Doxycycline

Explanation: ***Artemether-lumefantrine*** - **Artemether-lumefantrine** (Coartem) is the **WHO-recommended first-line treatment** for uncomplicated *P. falciparum* malaria, including **drug-resistant strains** (chloroquine-resistant, sulfadoxine-pyrimethamine resistant) - It is an **artemisinin-based combination therapy (ACT)** that is highly effective and **safe in pediatric patients** of all age groups, including infants ≥5 kg - The combination provides rapid parasite clearance (artemether) and eliminates residual parasites (lumefantrine), preventing resistance development - **ACTs remain the gold standard** for resistant P. falciparum malaria in children *Clindamycin* - **Clindamycin is NEVER used as monotherapy** for malaria due to its slow onset of action - It is used **only in combination with quinine or artesunate** for treatment of resistant or severe P. falciparum malaria when other options are unavailable - While safe in children, it is not a first-line agent and requires combination therapy *Tetracycline* - **Tetracycline** can be effective for malaria but is **absolutely contraindicated in children under 8 years** due to risk of permanent **tooth discoloration** (yellow-brown staining) and inhibition of bone growth - Therefore, it is unsuitable for the pediatric age group *Doxycycline* - **Doxycycline** is effective for malaria prophylaxis and treatment of resistant *P. falciparum* - However, like tetracycline, it is **contraindicated in children under 8 years** due to **dental staining** and skeletal development effects - Not appropriate for pediatric use in this age range

Question 474: A 5-year-old previously healthy child is taken from his day care to the pediatrician because his mother is concerned that the child has been fussy for the past few days and now has a rash on his face and torso. The mother also says the boy told her his head hurts, and she thinks he may have a low-grade fever. On examination the child is afebrile and not ill-appearing. He has a rash extending over his entire body except for the palms and soles. The infectious agent causing this disease can lead to what complication in immunocompromised hosts?

A. Progressive multifocal leukoencephalopathy
B. Aplastic anemia (Correct Answer)
C. Endemic Burkitt's lymphoma
D. Orchitis

Explanation: ***Aplastic anemia*** - This clinical presentation of a **rash** on the face and torso with **headache** and **low-grade fever** in a previously healthy child is characteristic of **erythema infectiosum** (fifth disease), caused by **Parvovirus B19**. - In immunocompromised hosts or those with underlying hematologic disorders (e.g., **sickle cell disease**), Parvovirus B19 infection can lead to **aplastic crisis** due to its tropism for **erythroid progenitor cells**, resulting in severe anemia. *Progressive multifocal leukoencephalopathy* - This is a severe demyelinating disease of the central nervous system caused by the **JC virus**, primarily affecting immunocompromised individuals. - It is not a complication associated with Parvovirus B19 infection. *Endemic Burkitt's lymphoma* - This aggressive B-cell lymphoma is strongly associated with **Epstein-Barr virus (EBV)** infection, particularly in areas endemic for malaria. - There is no association between Parvovirus B19 and Burkitt's lymphoma. *Orchitis* - **Orchitis**, or inflammation of the testicles, is a common complication of **mumps virus** infection, especially in post-pubertal males. - It is not a known complication of Parvovirus B19 infection.

Question 475: In a rural clinic, a 3-year-old girl child is brought by her mother and is emaciated. Her hemoglobin was 5 g/dL. The girl also has edema over her knees and ankles with discrete rash on her knees, ankles and elbows. The most likely worm infestation causing these manifestations is:

A. Roundworm
B. Pinworm
C. Whipworm
D. Hookworm (Correct Answer)

Explanation: ***Hookworm*** - **Hookworm infection** (Ancylostoma duodenale/Necator americanus) leads to chronic blood loss from the intestines, causing **microcytic hypochromic anemia** and **severe emaciation** due to persistent nutrient loss and malabsorption. - The combination of severe **anemia (Hb 5 g/dL)**, **emaciation**, and **edema** (due to **hypoalbuminemia**, a consequence of protein-losing enteropathy and poor nutrition) is highly characteristic of hookworm infestation in children. - The **discrete rash** on pressure points (knees, ankles, elbows) may represent **ground itch** (pruritic papulovesicular rash at larval penetration sites) or dermatitis secondary to malnutrition and edema. *Roundworm* - **Ascaris lumbricoides** can cause malnutrition and growth delays, but typically does not lead to the severe anemia and edema seen here unless there is a massive infestation leading to intestinal obstruction or biliary obstruction. - Its primary impact is often related to **nutrient competition** and mechanical obstruction, not significant blood loss. *Pinworm* - **Enterobius vermicularis** (pinworm) infection primarily causes **perianal itching**, especially at night. - It does not typically cause systemic symptoms like **severe anemia**, **emaciation**, or **edema**, as it does not feed on blood or cause significant nutrient malabsorption. *Whipworm* - **Trichuris trichiura** (whipworm) can cause chronic dysentery, **rectal prolapse**, and **anemia** in heavy infections due to blood loss. - While it can contribute to **growth retardation** and anemia, it is less likely to cause the profound emaciation and edema described compared to hookworm, especially with a hemoglobin level of 5 g/dL, which points strongly to major chronic blood loss.

Question 476: Congenital rubella syndrome is associated with:

A. Congenital heart disease
B. Sensorineural hearing loss
C. Cataract
D. All of the options (Correct Answer)

Explanation: ***All of the options*** - Congenital rubella syndrome (CRS) is well-known for causing a triad of **birth defects** affecting the heart, eyes, and ears, often referred to as **Gregg's triad**. - Exposure to the rubella virus during early pregnancy can lead to a range of severe and permanent anomalies in the developing fetus. *Congenital heart disease* - Common cardiac abnormalities associated with CRS include **patent ductus arteriosus (PDA)**, pulmonary artery stenosis, and ventricular septal defects (VSDs). - These defects arise from the virus interfering with the normal development of the **fetal heart** during the first trimester. *Sensorineural hearing loss* - This is one of the most common and often the **only manifestation** of CRS, leading to significant impairment. - The rubella virus can directly damage the **inner ear structures**, particularly the cochlea, resulting in permanent hearing loss. *Cataract* - Ocular defects such as **cataracts** (clouding of the lens), microphthalmia (small eyes), and glaucoma are characteristic features of CRS. - These conditions are due to the virus disrupting the normal development of the **fetal eye**, especially when infection occurs in the first 8 weeks of gestation.

Question 477: Congenital Rubella syndrome may have the following clinical features, except

A. Microcephaly
B. Neonatal hepatitis
C. Congenital cataract
D. Hydrocephalus (Correct Answer)

Explanation: ***Hydrocephalus*** - **Hydrocephalus** is generally *not* a characteristic feature of **congenital rubella syndrome (CRS)**. - While many devastating neurological developmental abnormalities can occur in utero, **hydrocephalus** specifically is not one of them. - CRS is associated with **microcephaly** (small brain), not hydrocephalus (enlarged ventricles). *Microcephaly* - **Microcephaly**, or an abnormally small head, is a common neurological sequel of **congenital rubella syndrome** due to brain damage. - The rubella virus can interfere with cell proliferation during fetal development, leading to **poor brain growth**. *Neonatal hepatitis* - **Neonatal hepatitis** can occur as part of the systemic manifestations of **congenital rubella syndrome**, resulting in **jaundice** and **liver dysfunction**. - The rubella virus can infect various organs, including the liver, causing inflammation and damage. *Congenital cataract* - **Congenital cataracts** are a classic ocular manifestation of **congenital rubella syndrome**, often leading to significant visual impairment. - The rubella virus can directly infect the developing lens, causing opacification. - Cataracts are part of the classic triad of CRS along with **cardiac defects** and **deafness**.

Question 478: A 30 month old deaf boy whose development is slower than normal is being followed for congenital cytomegalovirus (CMV) infection in your clinic.The child's mother is pregnant again and is worried about her new baby. Which of the following is true?

A. The new infant should be isolated from the older child
B. The mother has antibodies to CMV that are passed to the fetus (Correct Answer)
C. Termination of pregnancy is advised
D. The mother's infection cannot become reactivated

Explanation: ***The mother has antibodies to CMV that are passed to the fetus*** - The mother has a history of CMV infection, meaning she has developed **antibodies** against the virus. These maternal **IgG antibodies** can cross the placenta and provide passive immunity to the fetus. - This passive immunity helps protect the unborn baby from initial infection or reduce the severity of disease if exposure occurs, although it doesn't guarantee complete protection. *The new infant should be isolated from the older child* - Isolation is generally not necessary in this scenario because CMV is widespread and transmission through casual contact is common; strict isolation would be impractical and not significantly reduce risk. - While CMV can be shed in urine and saliva, the risk of symptomatic infection in the new infant from an older sibling with congenital CMV, especially if the mother is seropositive, is relatively low. *Termination of pregnancy is advised* - Termination of pregnancy is a major medical decision and is not advised solely based on a previous CMV infection in an older child. - The risk of severe congenital CMV in a subsequent pregnancy when the mother is already seropositive is significantly lower compared to a primary maternal infection during pregnancy. *The mother's infection cannot become reactivated* - CMV is a **herpesvirus** that establishes **latency** after primary infection, meaning it can reactivate later in life. - While reactivation can occur, particularly in immunocompromised individuals, it typically poses a much lower risk to a developing fetus compared to a primary infection during pregnancy, especially if the mother has pre-existing antibodies.

Question 479: Most common organism causing meningitis in a 1 year old child -

A. Listeria
B. H. influenzae
C. Neisseria meningitidis
D. Streptococcus pneumoniae (Correct Answer)

Explanation: ***Streptococcus pneumoniae*** - **_Streptococcus pneumoniae_** is currently the most prevalent cause of bacterial meningitis in children over **3 months of age**, including 1-year-olds, largely due to successful vaccination programs reducing other common pathogens. - Though **meningococcal disease** often presents with a fulminant course, **pneumococcal meningitis** is more frequently encountered among pathogens overall in this age group due to its widespread carriage and diverse serotypes. *Listeria* - **_Listeria monocytogenes_** is a significant cause of meningitis in **neonates** (under 1 month of age) and **immunocompromised individuals**, but less common in a healthy 1-year-old. - Transmission typically occurs vertically from mother to child or through contaminated food products. *H. influenzae* - **_Haemophilus influenzae_ type B (Hib)** was historically a major cause of meningitis in young children, but its incidence has dramatically decreased due to widespread **Hib vaccination**. - While other non-typeable strains or unvaccinated individuals can still be affected, it is no longer the most common cause in vaccinated populations. *Neisseria meningitidis* - **_Neisseria meningitidis_** is a significant cause of bacterial meningitis, particularly in children and young adults, often associated with epidemics and a **petechial rash**. - Although it can cause severe disease and outbreaks, **_Streptococcus pneumoniae_** tends to have a higher overall incidence in 1-year-olds in the post-Hib vaccine era.

Question 480: True about childhood tuberculosis:

A. Highly contagious
B. 5% prevalence
C. Common in 5-8 years age
D. Diagnosis by sputum is difficult (Correct Answer)

Explanation: ***Diagnosis by sputum is difficult*** - Children often have **pauci-bacillary disease**, meaning fewer bacteria are present in their sputum, making microbiological confirmation challenging. - Young children typically **cannot produce adequate sputum samples** voluntarily, unlike adults. - **Gastric aspirates** or induced sputum may be needed, but even these have lower diagnostic yield. - This is a hallmark feature distinguishing pediatric TB from adult TB. *Highly contagious* - Childhood tuberculosis, especially **extrapulmonary forms** or **pauci-bacillary disease**, is generally considered **less contagious** than adult pulmonary TB. - The reduced bacterial load and less forceful cough in children make transmission less efficient. - Children are more commonly victims than vectors of TB transmission. *5% prevalence* - The global prevalence of tuberculosis in children is highly variable and depends on specific regional epidemiology. - This figure is not a generally accepted statistic for childhood TB prevalence. *Common in 5-8 years age* - While TB can occur at any age, **children under 5 years old** are at highest risk for **severe and disseminated disease** (including TB meningitis and miliary TB). - Older children and adolescents might have clinical presentations more akin to adult TB, but the 5-8 year age range is not specifically highlighted as the peak age for childhood TB.

Practice by Chapter

Vaccine-Preventable Diseases

Practice Questions

Immunization Schedule

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Common Childhood Infections

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Pediatric HIV

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Congenital Infections

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Fever in Infants and Children

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Meningitis and Encephalitis

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Respiratory Tract Infections

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Gastrointestinal Infections

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Parasitic Infections

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Tuberculosis in Children

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Opportunistic Infections

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