Infectious Diseases — MCQs
On this page
Which condition is characterized by a "slapped cheek" appearance in children?
A 1-year-old child is brought in for routine vaccination. Which of the following vaccines is typically administered at this age to provide immunity against multiple diseases?
A 5-year-old boy presents with a rash that began on his face and has spread to his trunk and limbs. The rash consists of red patches that give a 'slapped cheek' appearance on the face, followed by a lacy, net-like rash on the trunk and limbs, and he also has a low-grade fever. What is the most likely diagnosis?
A 6-month-old infant is brought to the clinic with a history of severe cough. Upon examination, the child exhibits severe respiratory distress and is diagnosed with pertussis. Which vaccine is recommended for prevention?
What is the next best step in managing a child presenting with fever and metaphyseal bone pain, suspected of having acute osteomyelitis?
Which of the following is the most common cause of pneumonia in a 2-year-old child?
A 3-year-old child presents with a history of high fever, irritability, and refusal to move the right hip. What is the most likely diagnosis?
A 7-year-old girl presents with a sore throat, fever, and a strawberry tongue. Which of the following conditions is most likely?
A 2-month-old infant presents with poor feeding, irritability, and a bulging anterior fontanelle. What is the most likely diagnosis?
Which viral infection is associated with Koplik spots and a maculopapular rash?
Infectious Diseases Indian Medical PG Practice Questions and MCQs
Question 521: Which condition is characterized by a "slapped cheek" appearance in children?
- A. Fifth disease (Correct Answer)
- B. Scarlet fever
- C. Kawasaki disease
- D. Measles
Explanation: ***Fifth disease*** - Also known as **Erythema infectiosum**, this viral illness is caused by **Parvovirus B19** and classically presents with a distinctive erythematous rash on the cheeks, giving a **"slapped cheek" appearance**. - Following the facial rash, a **lacy, reticular rash** typically appears on the trunk and extremities. *Scarlet fever* - Characterized by a **fine, sandpaper-like rash** that starts on the neck and chest and spreads throughout the body, often sparing the area around the mouth (circumoral pallor). - It is caused by **Streptococcus pyogenes** and is associated with a **strawberry tongue** and fever. *Kawasaki disease* - An acute systemic vasculitis primarily affecting young children, presenting with prolonged fever, **conjunctivitis**, **oral mucosal changes** (strawberry tongue, red cracked lips), **rash**, and **cervical lymphadenopathy**. - It does not typically cause a "slapped cheek" rash. *Measles* - Characterized by a **maculopapular rash** that typically starts on the face and behind the ears, then spreads downwards. - Prior to the rash, **Koplik spots** (small white spots on the buccal mucosa) are pathognomonic.
Question 522: A 1-year-old child is brought in for routine vaccination. Which of the following vaccines is typically administered at this age to provide immunity against multiple diseases?
- A. MMR vaccine (Correct Answer)
- B. BCG vaccine
- C. Hepatitis B vaccine
- D. Influenza vaccine
Explanation: ***MMR vaccine*** - The **Measles, Mumps, and Rubella (MMR) vaccine** is typically recommended for administration at **9-12 months of age** (first dose at 9 months as per IAP schedule, or 12-15 months as per WHO/CDC) as part of routine childhood immunizations. - It provides protection against **three common childhood diseases** (measles, mumps, and rubella) with a single shot. - This is the **primary multi-disease vaccine** given at this age. *BCG vaccine* - The **Bacillus Calmette-Guérin (BCG) vaccine** primarily protects against **tuberculosis** and is typically given **at birth** as per the Indian immunization schedule. - It is not a multi-disease vaccine and is not administered at 1 year of age. *Hepatitis B vaccine* - The **Hepatitis B vaccine** is administered in a **series**, with the first dose given at **birth**, followed by doses at 6, 10, and 14 weeks of age. - It specifically targets the **Hepatitis B virus** only and is not a multi-disease vaccine given at 1 year. *Influenza vaccine* - The **influenza vaccine** is recommended **annually** starting at **6 months of age**, but it targets **seasonal influenza strains** only. - It is not considered a routine multi-disease vaccine like MMR for childhood immunization.
Question 523: A 5-year-old boy presents with a rash that began on his face and has spread to his trunk and limbs. The rash consists of red patches that give a 'slapped cheek' appearance on the face, followed by a lacy, net-like rash on the trunk and limbs, and he also has a low-grade fever. What is the most likely diagnosis?
- A. Scarlet Fever
- B. Measles
- C. Erythema Infectiosum (Correct Answer)
- D. Roseola
Explanation: ***Erythema Infectiosum*** - The distinctive **'slapped cheek' rash** on the face, followed by a **lacy, reticular (net-like) rash** spreading to the trunk and limbs, is characteristic of Erythema Infectiosum, also known as Fifth Disease, caused by **Parvovirus B19**. - It often presents with a **low-grade fever** and is more common in school-aged children. *Scarlet Fever* - Characterized by a **fine, sandpaper-like rash** that blanches with pressure and often starts on the neck and chest before spreading. - Typically accompanied by a **high fever**, sore throat, and swollen lymph nodes, due to a **Group A Streptococcus** infection. *Measles* - Measles rash typically presents as **maculopapular, erythematous lesions** that start behind the ears and on the face, spreading downwards. - It is preceded by **Koplik spots** (small white spots on the buccal mucosa) and a prodrome of high fever, cough, conjunctivitis, and coryza. *Roseola* - Roseola is characterized by a **high fever** (often >103°F) that lasts for 3-5 days, followed by the sudden appearance of a **rose-pink maculopapular rash** once the fever breaks. - The rash usually starts on the trunk and spreads to the neck and extremities, but does not present with a "slapped cheek" or lacy appearance.
Question 524: A 6-month-old infant is brought to the clinic with a history of severe cough. Upon examination, the child exhibits severe respiratory distress and is diagnosed with pertussis. Which vaccine is recommended for prevention?
- A. Live attenuated
- B. Conjugate
- C. Inactivated
- D. Subunit (Correct Answer)
Explanation: ***Subunit*** - The **pertussis vaccine** (DTaP for infants/children and Tdap for adolescents/adults) is a **subunit vaccine**, meaning it contains only specific purified antigens from the *Bordetella pertussis* bacterium, such as pertussis toxin, filamentous hemagglutinin, and pertactin. - This type of vaccine is used because the whole-cell pertussis vaccine (DTP) was associated with a higher rate of adverse effects, leading to the development of safer acellular subunit formulations. *Live attenuated* - **Live attenuated vaccines** contain a weakened form of the pathogen that can replicate in the host without causing severe disease, providing a strong immune response (e.g., MMR, varicella, rotavirus). - While effective, live attenuated vaccines are generally not used for pertussis due to concerns about safety and potential for reversion to virulence in some cases. *Inactivated* - **Inactivated vaccines** contain whole pathogens that have been killed or inactivated, preventing them from replicating but retaining their antigenicity (e.g., inactivated polio vaccine, influenza vaccine). - While one of the older pertussis vaccines (DTP) was a **whole-cell inactivated vaccine**, the current recommended DTaP/Tdap vaccines are **acellular subunit vaccines**, which are safer due to fewer adverse reactions. *Conjugate* - **Conjugate vaccines** are created by chemically linking a polysaccharide antigen (which is T-cell independent) to a protein carrier (which is T-cell dependent), thereby eliciting a more robust and long-lasting immune response, especially in infants (e.g., Hib, pneumococcal, meningococcal vaccines). - The pertussis vaccine is not a conjugate vaccine; its antigens are primarily proteins (e.g., pertussis toxin), not polysaccharides conjugated to a carrier protein.
Question 525: What is the next best step in managing a child presenting with fever and metaphyseal bone pain, suspected of having acute osteomyelitis?
- A. Wait for MRI results before starting treatment
- B. Conduct a bone biopsy immediately
- C. Obtain a blood culture and perform imaging
- D. Start empirical antibiotics immediately (Correct Answer)
Explanation: ***Start empirical antibiotics immediately*** - In a child with suspected **acute osteomyelitis**, prompt initiation of empirical antibiotics is crucial to prevent further bone destruction and systemic spread of infection. - Waiting for culture results or extensive imaging can delay treatment, leading to worse outcomes, including **septic arthritis** or chronic osteomyelitis. *Obtain a blood culture and perform imaging* - While **blood cultures** and **imaging** (such as X-rays, ultrasound, or MRI) are essential diagnostic steps, they should be performed concurrently with, or immediately after, the initiation of empirical antibiotics. - Imaging confirms the diagnosis and extent, while cultures identify the causative organism, but neither should delay the initial therapeutic intervention. *Wait for MRI results before starting treatment* - **Magnetic Resonance Imaging (MRI)** is highly sensitive for diagnosing osteomyelitis, but waiting for MRI results can cause a significant delay in treatment, especially in an acute setting. - This delay increases the risk of complications such as **bone damage** or spread of infection. *Conduct a bone biopsy immediately* - A **bone biopsy** provides definitive diagnosis and allows for targeted antibiotic therapy based on culture results, but it is an invasive procedure and not the immediate first step. - It is typically reserved for cases where initial empirical antibiotic therapy fails or the diagnosis remains uncertain despite other diagnostic tests.
Question 526: Which of the following is the most common cause of pneumonia in a 2-year-old child?
- A. Haemophilus influenzae
- B. Mycoplasma pneumoniae
- C. RSV
- D. Streptococcus pneumoniae (Correct Answer)
Explanation: ***Streptococcus pneumoniae*** - **Streptococcus pneumoniae** is the **most common cause of bacterial pneumonia** in children aged 2 months to 5 years, including 2-year-olds. - Remains the leading bacterial pathogen causing community-acquired pneumonia in this age group despite pneumococcal vaccination. - Typically presents with **lobar pneumonia**, high fever, and may be associated with **pleural effusion** or empyema in severe cases. - The **13-valent pneumococcal conjugate vaccine (PCV13)** has reduced incidence but S. pneumoniae remains the predominant bacterial cause. *RSV* - **Respiratory Syncytial Virus (RSV)** is the most common cause of **bronchiolitis** and lower respiratory tract infections in **infants**, particularly those aged **2-8 months**. - By age 2 years, RSV remains a cause of viral pneumonia but is significantly less common than in infancy. - When it does occur at this age, it tends to be less severe than in younger infants. *Haemophilus influenzae* - **Non-typeable Haemophilus influenzae** can cause pneumonia but is less common than S. pneumoniae. - **Haemophilus influenzae type b (Hib)** vaccine has dramatically reduced invasive Hib disease, including pneumonia. - Now accounts for a much smaller proportion of childhood pneumonia cases in vaccinated populations. *Mycoplasma pneumoniae* - **Mycoplasma pneumoniae** is a common cause of **atypical pneumonia** in **school-aged children** (>5 years) and adolescents. - Uncommon in children under 5 years of age, though can occasionally occur. - Presents with gradual onset, dry cough, and extrapulmonary manifestations (rash, myalgias).
Question 527: A 3-year-old child presents with a history of high fever, irritability, and refusal to move the right hip. What is the most likely diagnosis?
- A. Septic arthritis (Correct Answer)
- B. Transient synovitis
- C. Legg-Calvé-Perthes disease
- D. Slipped capital femoral epiphysis
Explanation: ***Septic arthritis*** - The combination of **high fever, irritability, and refusal to move the hip** in a 3-year-old child is highly suggestive of **septic arthritis**, a medical emergency [1]. - This condition involves an **infection within the joint space**, leading to severe pain and limited range of motion due to inflammation and pus accumulation [2]. *Transient synovitis* - While it causes hip pain and refusal to bear weight, **transient synovitis** typically presents with a **lower-grade or no fever** and less severe systemic symptoms [2]. - It is a self-limiting inflammation of the hip joint that usually follows a **viral infection**. *Legg-Calvé-Perthes disease* - This condition is characterized by **avascular necrosis of the femoral head** and typically presents with a **limp** and **insidious onset of hip pain**, usually without fever or acute irritability. - It usually affects children between 4 and 8 years old, and **fever is generally absent**. *Slipped capital femoral epiphysis* - This condition occurs when the **femoral head slips off the femoral neck** through the growth plate and is more common in **adolescents (typically 10-16 years)**, particularly during periods of rapid growth [1]. - It usually presents with **hip or knee pain and a limp** but generally **without fever**.
Question 528: A 7-year-old girl presents with a sore throat, fever, and a strawberry tongue. Which of the following conditions is most likely?
- A. Scarlet fever (Correct Answer)
- B. Kawasaki disease
- C. Infectious mononucleosis
- D. Hand-foot-and-mouth disease
Explanation: ***Scarlet fever*** - The classic triad of **sore throat**, **fever**, and **strawberry tongue** is highly characteristic of scarlet fever, a systemic illness caused by toxigenic strains of **Group A Streptococcus**. - Other common findings include a **scarlatiniform rash** (sandpaper-like texture) and **circumoral pallor**. *Kawasaki disease* - While it can present with fever and strawberry tongue, Kawasaki disease typically involves **bilateral conjunctival injection**, **polymorphous rash**, **cervical lymphadenopathy**, and changes in **extremities** (e.g., desquamation). - It usually occurs in children younger than 5 years and lacks the prominent pharyngitis associated with scarlet fever. *Infectious mononucleosis* - Caused by the **Epstein-Barr virus**, it is characterized by **fever**, **pharyngitis**, **lymphadenopathy**, and sometimes **splenomegaly**. - A strawberry tongue is not a typical feature, and the pharyngitis is often exudative. *Hand-foot-and-mouth disease* - This viral illness, often caused by **Coxsackievirus**, presents with **fever**, **oral lesions** (herpangina-like), and a characteristic rash on the **hands and feet** (vesicular or papular). - A strawberry tongue is not a typical or distinguishing feature of hand-foot-and-mouth disease.
Question 529: A 2-month-old infant presents with poor feeding, irritability, and a bulging anterior fontanelle. What is the most likely diagnosis?
- A. Hydrocephalus
- B. Meningitis (Correct Answer)
- C. Intraventricular Hemorrhage
- D. Cerebral Palsy
Explanation: ***Meningitis*** - The **classic triad** of a **bulging anterior fontanelle**, **poor feeding**, and **irritability** in a 2-month-old infant is highly suggestive of **meningitis**. - A bulging fontanelle indicates **increased intracranial pressure**, which in the context of fever, poor feeding, and irritability points to **central nervous system infection**. - Infants with meningitis often present with **non-specific symptoms** due to an underdeveloped immune system, making this constellation of findings critical for diagnosis. - **Immediate lumbar puncture** and empirical antibiotics are warranted given the high morbidity and mortality of bacterial meningitis in this age group. *Hydrocephalus* - While hydrocephalus can cause a **bulging fontanelle** due to increased intracranial pressure, it typically presents with **progressive head circumference enlargement** over weeks to months. - The **acute presentation** with irritability and poor feeding, without mention of increasing head size or developmental concerns, makes an **infectious etiology more likely**. - Hydrocephalus would be a more chronic process rather than the acute presentation described. *Intraventricular Hemorrhage* - **Intraventricular hemorrhage (IVH)** primarily affects **premature infants** in the first few days of life, not typically term infants at 2 months of age. - IVH presents with **acute neurological deterioration**, **apnea**, **bradycardia**, and **seizures**, often with a sudden drop in hematocrit. - The absence of prematurity history and the subacute presentation make IVH much less likely than meningitis. *Cerebral Palsy* - **Cerebral palsy** is a **non-progressive motor disorder** resulting from perinatal brain injury, not an acute illness. - CP presents with **delayed motor milestones**, **abnormal muscle tone**, and **persistent primitive reflexes**, typically diagnosed after 6-12 months of age. - A bulging fontanelle and acute symptoms like poor feeding and irritability are **not features of cerebral palsy**.
Question 530: Which viral infection is associated with Koplik spots and a maculopapular rash?
- A. Rubella
- B. Varicella
- C. Measles (Correct Answer)
- D. Cytomegalovirus
Explanation: ***Measles*** - **Koplik spots** are pathognomonic for measles, appearing as small, white spots on a red background on the buccal mucosa. - The **maculopapular rash** of measles typically starts on the face and behind the ears, then spreads downwards to the trunk and extremities. *Rubella* - While rubella presents with a **maculopapular rash**, it does not cause Koplik spots. - The rubella rash is usually fainter and clears more rapidly than measles. *Varicella* - Varicella, or **chickenpox**, is characterized by a vesicular rash that progresses from macules to papules, vesicles, and scabs. - It does not present with Koplik spots or a typical maculopapular rash. *Cytomegalovirus* - CMV infection can cause a variety of symptoms, including fever, fatigue, and sometimes a rash, especially in immunocompromised individuals. - It is not associated with either Koplik spots or a characteristic maculopapular rash.
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