Infectious Diseases Practice Questions

Q: A 12-year-old boy develops a sore throat of 4-day duration. On examination, a yellow-grayish patch is seen over both tonsils, and a foul smell is coming from his mouth. Which non-suppurative complication is most commonly associated with streptococcal throat infections?

Acute rheumatic fever. ***Acute rheumatic fever*** - **Acute rheumatic fever (ARF)** is a serious **non-suppurative complication** of streptococcal pharyngitis, primarily caused by **Group A Streptococcus (GAS)** [1]. - It involves **inflammatory lesions** of the heart, joints, brain, and subcutaneous tissues [2]. *Acute glomerulonephritis* - This is also a **non-suppurative complication** of streptococcal infection but is typically less common than acute rheumatic fever following pharyngitis. - **Acute post-streptococcal glomerulonephritis** is more frequently associated with **streptococcal skin infections (impetigo)** than pharyngeal infections. *Scarlet fever* - **Scarlet fever** is a **toxin-mediated disease** that is a direct manifestation of a streptococcal infection, not a non-suppurative complication. - It presents with a characteristic **rash**, **strawberry tongue**, and fever, making it a different category of streptococcal sequela. *Both acute rheumatic fever and acute glomerulonephritis* - While both can be non-suppurative complications, **acute rheumatic fever** is the **most commonly associated** non-suppurative complication specifically with **streptococcal throat infections** [1]. - **Acute glomerulonephritis** has a stronger association with **skin infections** and is less common after pharyngitis compared to acute rheumatic fever.

Q: All of the following are contraindications to the pertussis-containing vaccine except which of the following?

No known allergies. ***No known allergies*** - The absence of known allergies is **not a contraindication** to vaccination; rather, it suggests an individual is less likely to experience an **allergic reaction**. - This option describes a **normal and healthy** patient profile, suitable for vaccination. *Uncontrolled epilepsy* - **Uncontrolled epilepsy** represents an **unstable neurological condition** and is a **contraindication** to pertussis vaccination per current guidelines. - Progressive or unstable neurological disorders are contraindications because vaccination might be **temporally associated** with neurological deterioration, making it difficult to determine causality. - Once epilepsy is **controlled and stable**, pertussis vaccination may be reconsidered. *Anaphylactic reaction to previous dose* - A confirmed **anaphylactic reaction** to a prior dose of any vaccine component is an **absolute contraindication** to further doses. - Re-exposure could lead to a **severe and life-threatening** allergic response. *Progressive encephalopathy* - **Progressive encephalopathy** without an identified cause occurring within 7 days after a previous dose of pertussis vaccine is an **absolute contraindication**. - Vaccination in this context could exacerbate the condition or confuse the diagnosis of the underlying encephalopathy.

Q: What is the most common cause of acute epiglottitis in children in the post-Hib vaccination era?

Streptococcus pyogenes (Group A Strep). ***Streptococcus pyogenes (Group A Strep)*** - In the **post-Hib vaccination era**, *Streptococcus pyogenes* has emerged as **one of the most common causes** of acute epiglottitis in children. - With the dramatic reduction in H. influenzae type B cases due to widespread vaccination, Group A Streptococcus now accounts for a significant proportion of bacterial epiglottitis cases. - Other common causes in the current era include *Streptococcus pneumoniae* and *Staphylococcus aureus*. *Hemophilus influenzae type B* - While H. influenzae type B was the **predominant cause in the pre-vaccination era**, its incidence has **declined by over 95%** since the introduction of the Hib vaccine. - Cases now occur primarily in **unvaccinated or incompletely vaccinated children** and are relatively rare in populations with high vaccination coverage. - The question specifically asks about the post-Hib vaccination era, making this no longer the most common cause. *Para influenza virus type I and II* - **Parainfluenza viruses**, particularly types I and II, are the **leading cause of croup** (laryngotracheobronchitis), not epiglottitis. - Croup primarily affects the **subglottic region** and presents with a characteristic **barking cough**, whereas epiglottitis involves the supraglottic structures and presents with drooling, dysphagia, and the "tripod position." *Streptococcus pneumoniae* - *Streptococcus pneumoniae* is also a **common cause of acute epiglottitis in the post-Hib era**, along with Group A Streptococcus. - While S. pneumoniae can cause epiglottitis, Group A Strep is generally cited more frequently in recent literature as a leading bacterial cause in the current era. - Both organisms have become more prominent as etiologic agents following the decline of H. influenzae type B.

Q: Which of the following statements is true about erythema infectiosum?

It is caused by parvovirus B19.. ***It is caused by parvovirus B19.*** - **Parvovirus B19** is the definitive etiological agent of erythema infectiosum, also known as fifth disease. - This viral infection is common in **children** and presents with a characteristic rash. *The rash appears on the head and neck.* - The classic **slapped-cheek rash** does appear on the face (cheeks), but the more characteristic **lacy, reticular rash** typically appears on the **trunk and extremities**. - The neck is not a primary site of involvement, and this option is incomplete as it doesn't mention the distinctive truncal and extremity distribution. *The rash appears during the febrile phase.* - In erythema infectiosum, the **rash typically appears after the fever has subsided** (if fever was present at all). - The prodromal symptoms (mild fever, malaise) resolve before the characteristic slapped-cheek rash emerges. - By the time the rash appears, the patient is usually feeling better and is in the convalescent phase. *It primarily affects adults.* - Erythema infectiosum primarily affects **children**, particularly those of school age (5-15 years). - While adults can contract the infection, it is far more common in childhood.

Q: Which of the following is the MOST COMMON manifestation of congenital rubella syndrome?

Sensory neural hearing loss. ***Sensorineural hearing loss*** - **Sensorineural hearing loss** is the **most common manifestation** of congenital rubella syndrome, affecting **60-90% of infected infants**, and is often the **only manifestation** present. - It can be **unilateral or bilateral** and is typically **permanent**, ranging from mild to profound. - It is the **most frequent sequela** and may be the sole defect in many cases. *Cataract* - While **cataracts** are a classic component of the congenital rubella syndrome **triad** (cataracts, cardiac defects, deafness), they occur in **30-50% of cases**. - They are **less common** than sensorineural hearing loss. - Other ocular manifestations include **retinopathy**, **glaucoma**, and **microphthalmia**. *Congenital heart disease* - **Congenital heart disease**, particularly **patent ductus arteriosus (PDA)** and **peripheral pulmonary artery stenosis**, is a classic manifestation. - It occurs in **40-60% of cases**, making it **less common** than hearing loss. - Cardiovascular defects are part of the classic triad but not the most frequent finding. *None of the options* - This option is incorrect because **sensorineural hearing loss** is the well-established **most common manifestation** of congenital rubella syndrome. - It is the **single most frequent defect** identified in affected children.

Q: Nagayama spots are seen in

Roseola infantum. ***Roseola infantum*** - **Nagayama spots** are **erythematous papules** on the **uvula and soft palate** that are characteristic of **roseola infantum**, also known as **exanthem subitum**. - This viral illness, typically caused by **HHV-6** or **HHV-7**, primarily affects infants and young children, presenting with a high fever followed by a characteristic rash. *Measles* - Measles (rubeola) is characterized by **Koplik spots**, which are **bluish-white spots on the buccal mucosa** adjacent to the molars. - While measles also causes a rash, its specific enanthem is distinct from Nagayama spots. *Mumps* - Mumps is a viral infection primarily causing **parotitis** (swelling of the salivary glands)**. - It does not typically present with specific oral lesions like Nagayama spots or Koplik spots. *Rubella* - Rubella, or German measles, is characterized by a **maculopapular rash** that spreads rapidly but less intensely than measles. - While it may cause **Forchheimer spots** (petechiae on the soft palate), these are different from Nagayama spots and often less distinct.

Q: While discharging a patient of meningitis due to Haemophilus influenzae, what is the essential step you would take?

Test for hearing loss using auditory response testing. ***Test for hearing loss using auditory response testing*** - **Hearing loss** is a common and serious complication of *Haemophilus influenzae* meningitis, potentially affecting up to 30% of survivors, and early detection is crucial for intervention [1]. - **Auditory brainstem response (ABR) testing** is a reliable method to assess hearing function in patients, especially children, after meningitis. *Perform an EEG to assess brain activity* - While meningitis can cause neurological complications like seizures, an **EEG** is primarily indicated for assessing **seizure activity** or other significant alterations in brain electrical function, not as a routine discharge step for all *Haemophilus influenzae* meningitis patients [2]. - An EEG would be performed if there were **clinical signs of seizures** or other neurological deficits requiring immediate investigation during hospitalization, rather than as a discharge routine. *Assess the patient's developmental milestones* - Assessing **developmental milestones** is important for all children, especially after a severe illness like meningitis, but it is a **long-term follow-up** concern and not an essential **immediate discharge step** focused on a specific, common complication. - Developmental assessments are typically part of routine pediatric check-ups and ongoing neurodevelopmental surveillance, rather than a single acute discharge intervention. *Refer the patient for physical rehabilitation* - **Physical rehabilitation** is necessary if the patient has experienced **motor deficits** or other physical impairments due to meningitis-related complications, such as stroke or cerebral palsy. - However, it is not an essential universal discharge step for all meningitis patients; it is only indicated if specific rehabilitation needs have been identified.

Q: Which throat infection in a child requires systemic antibiotic therapy?

Group A beta-hemolytic streptococci. ***Group A beta-hemolytic streptococci*** - **Group A streptococcal (GAS) pharyngitis** (strep throat) is a common bacterial infection in children that requires antibiotic treatment to prevent **rheumatic fever** and **glomerulonephritis**. - Systemic antibiotics are crucial to eradicate the bacteria and reduce the risk of these serious **post-streptococcal complications**. *Pneumococci* - **Pneumococcal infections** typically manifest as otitis media, pneumonia, or sinusitis, not primarily as throat infections warranting oral antibiotics in otherwise healthy children. - While *Streptococcus pneumoniae* can colonize the nasopharynx, it rarely causes pharyngitis requiring specific treatment as a sole diagnosis. *Staph aureus* - *Staphylococcus aureus* is an uncommon cause of **pharyngitis** in children and does not typically lead to the severe systemic complications associated with GAS that necessitate routine antibiotic therapy. - Pharyngeal infections with *S. aureus* are often more problematic in specific populations (e.g., immunocompromised) and do not usually present as typical "strep throat." *All of the options* - This option is incorrect because only **Group A beta-hemolytic streptococci** consistently require systemic antibiotic therapy for uncomplicated pharyngitis in children due to the risk of significant post-infectious complications. - **Pneumococci** and **Staph aureus** do not typically cause pharyngitis that necessitates this specific management strategy in the same context.

Q: Which of the following is not a complication of Congenital Rubella Syndrome (CRS)?

Macrocephaly. ***Macrocephaly*** - While CRS can lead to various neurological complications, **macrocephaly** (abnormally large head circumference) is not a typical manifestation of the syndrome. Neurological issues in CRS more commonly involve **microcephaly** due to brain damage. - Other common neurological complications include **meningoencephalitis** and developmental delays, but not an enlarged head. *Retinopathy* - **Pigmentary retinopathy** (salt-and-pepper retinopathy) is a classic ocular manifestation of CRS, often present at birth. - This is a direct consequence of the rubella virus affecting the developing retinal structures. *Spontaneous abortion* - Maternal rubella infection, especially during the **first trimester**, carries a significant risk of **spontaneous abortion** due to severe fetal damage. - The virus's teratogenic effects can be so profound that the fetus is not viable. *Cardiac abnormalities* - **Congenital heart defects** are a hallmark of CRS, with **patent ductus arteriosus (PDA)** and **pulmonary artery stenosis** being the most common. - These abnormalities result from the rubella virus interfering with normal cardiac development during embryogenesis.

Q: Treatment of whooping cough is

Erythromycin. ***Erythromycin*** - **Macrolide antibiotics** like erythromycin are the **first-line treatment** for whooping cough (*Bordetella pertussis*), especially when administered early in the catarrhal stage. - They work by **eradicating the bacteria**, **reducing the duration of infectiousness**, and can lessen the severity and duration of symptoms if given promptly. *Rifampicin* - **Rifampicin** is primarily used in the treatment of **tuberculosis** and other mycobacterial infections, not whooping cough. - Its mechanism of action involves inhibiting bacterial RNA synthesis, which is not the preferred strategy for *Bordetella pertussis*. *Tetracycline* - While **tetracyclines** are broad-spectrum antibiotics, they are generally **not recommended for whooping cough** due to potential side effects, particularly in young children (e.g., tooth discoloration). - Macrolides are superior and safer alternatives for *Bordetella pertussis* infection. *Ampicillin* - **Ampicillin** is a **beta-lactam antibiotic** commonly used for various bacterial infections, but it is **ineffective against *Bordetella pertussis***. - *Bordetella pertussis* shows resistance to penicillins and other beta-lactams, likely due to **beta-lactamase production** and the organism's location in the respiratory tract where beta-lactams may not achieve adequate bactericidal concentrations.

Question 1

A 12-year-old boy develops a sore throat of 4-day duration. On examination, a yellow-grayish patch is seen over both tonsils, and a foul smell is coming from his mouth. Which non-suppurative complication is most commonly associated with streptococcal throat infections?

Accepted Answer

Acute rheumatic fever

Answer

Acute glomerulonephritis

Answer

Scarlet fever

Answer

Both acute rheumatic fever and acute glomerulonephritis

Question 2

All of the following are contraindications to the pertussis-containing vaccine except which of the following?

Accepted Answer

No known allergies

Answer

Uncontrolled epilepsy

Answer

Anaphylactic reaction to previous dose

Answer

Progressive encephalopathy

Question 3

What is the most common cause of acute epiglottitis in children in the post-Hib vaccination era?

Accepted Answer

Streptococcus pyogenes (Group A Strep)

Answer

Hemophilus influenzae type B

Answer

Para influenza virus type I and II

Answer

Streptococcus pneumoniae

Question 4

Which of the following statements is true about erythema infectiosum?

Accepted Answer

It is caused by parvovirus B19.

Answer

The rash appears on the head and neck.

Answer

The rash appears during the febrile phase.

Answer

It primarily affects adults.

Question 5

Which of the following is the MOST COMMON manifestation of congenital rubella syndrome?

Accepted Answer

Sensory neural hearing loss

Answer

None of the options

Answer

Congenital heart disease

Answer

Cataract

Question 6

Nagayama spots are seen in

Accepted Answer

Roseola infantum

Answer

Measles

Answer

Mumps

Answer

Rubella

Question 7

While discharging a patient of meningitis due to Haemophilus influenzae, what is the essential step you would take?

Accepted Answer

Test for hearing loss using auditory response testing

Answer

Assess the patient's developmental milestones

Answer

Refer the patient for physical rehabilitation

Answer

Perform an EEG to assess brain activity

Question 8

Which throat infection in a child requires systemic antibiotic therapy?

Accepted Answer

Group A beta-hemolytic streptococci

Answer

Pneumococci

Answer

Staph aureus

Answer

All of the options

Question 9

Which of the following is not a complication of Congenital Rubella Syndrome (CRS)?

Accepted Answer

Macrocephaly

Answer

Retinopathy

Answer

Cardiac abnormalities

Answer

Spontaneous abortion

Question 10

Treatment of whooping cough is

Accepted Answer

Erythromycin

Answer

Rifampicin

Answer

Tetracycline

Answer

Ampicillin

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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