Infectious Diseases Practice Questions

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

Hepatitis A virus infection. ***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.

Q: 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?

pneumonia. ***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.

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

IV Ceftriaxone. ***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.

Q: Which of the following is Not characteristic of congenital Syphilis?

Ghon complex. ***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**.

Q: Raspberry tongue is a feature of

Scarlet fever. ***Scarlet fever*** - **Raspberry (or strawberry) tongue** is a classic sign of **scarlet fever**, characterized by an initial white coating that peels, revealing red, swollen papillae [1]. - This symptom is caused by the **erythrogenic toxins** produced by Group A Streptococcus bacteria, which are responsible for scarlet fever [1]. *Yellow fever* - Yellow fever is a **viral hemorrhagic disease** transmitted by mosquitoes, typically presenting with fever, muscle aches, and **jaundice**. - It does not present with characteristic tongue changes like a **raspberry tongue**. *Mamba's disease* - **Mamba's disease** is not a recognized medical condition; it does not exist in standard medical literature. - This option is a distractor, as such it is not associated with any specific clinical features, including tongue changes. *Katayama fever* - Katayama fever is an **acute manifestation of schistosomiasis** (snail fever) occurring shortly after exposure to contaminated water. - Symptoms usually include high fever, cough, hepatosplenomegaly, and eosinophilia, but **not a raspberry tongue**.

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

Influenza virus. ***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

Q: A 4-year-old child presented with fever for 6 days, generalized rash and cervical lymphadenopathy with strawberry tongue. What could be the diagnosis?

Kawasaki disease. ***Kawasaki disease*** * Kawasaki disease is a **vasculitis** affecting medium-sized arteries, predominantly in children. * **Persistent fever** for more than 5 days, **generalized rash**, **cervical lymphadenopathy**, and **strawberry tongue** are key diagnostic criteria. * The child's age (4 years) is also consistent with the typical presentation of Kawasaki disease. *Kimura disease* * Kimura disease is a **rare chronic inflammatory condition** primarily affecting the head and neck, characterized by subcutaneous nodules and enlarged lymph nodes. * It typically presents with **painless subcutaneous masses**, often in young adults of Asian descent, and does not commonly include a generalized rash or strawberry tongue. *Scarlet fever* * Scarlet fever is caused by **Group A Streptococcus** and typically presents with a **fine, sandpaper-like rash**, **strawberry tongue**, and fever. * While a strawberry tongue and rash are present, the rash of Kawasaki disease is more polymorphous, and cervical lymphadenopathy is often more pronounced and less generalized than in scarlet fever. *Rosai Dorfman disease* * Rosai-Dorfman disease, also known as **sinus histiocytosis with massive lymphadenopathy**, is characterized by striking, often **painless and massive lymph node enlargement**, predominantly in the cervical region. * Systemic symptoms like fever and rash can occur, but the classic presentation does not typically include a "strawberry tongue" or the specific constellation of symptoms seen in Kawasaki disease.

Q: The following age group is most severely affected by Rubella infection -

Unborn child. ***Unborn child*** - Rubella infection during pregnancy, especially in the **first trimester**, can lead to **Congenital Rubella Syndrome (CRS)**, causing severe birth defects. - CRS can manifest as **cardiac malformations**, **cataracts**, **deafness**, and neurological disorders, making it the most severely affected group. *Young girls* - While susceptible to rubella, young girls typically experience a **mild, self-limiting disease** with a rash, low-grade fever, and lymphadenopathy. - The risk of severe complications as seen in CRS is significantly lower in this age group compared to an unborn child. *Adolescent girls* - Rubella infection in adolescent girls is generally a **mild illness**, similar to young girls, characterized by a rash and mild constitutional symptoms. - The main concern for this group is if they become pregnant, as **maternal infection** then poses a severe risk to the fetus, not the adolescent herself. *Females aged 25 -- 35 Year* - In this age group, rubella infection is typically **mild and self-limiting**, similar to younger females. - The primary concern is if the woman is pregnant or becomes pregnant, as the **teratogenic effects** on the fetus are devastating, not the severity of the disease in the mother.

Q: Most common organism causing bacterial meningitis between 6 months and 2 years in vaccinated populations.

Pneumococcus. ***Pneumococcus*** - **Pneumococcus (Streptococcus pneumoniae)** is now the most common cause of bacterial meningitis in children aged 6 months to 2 years in countries with high vaccination rates for *H. influenzae type b (Hib)* and *N. meningitidis*. - The introduction of the **pneumococcal conjugate vaccine (PCV)** has significantly reduced the incidence of pneumococcal meningitis, but it still remains the leading cause among the remaining cases in this age group. *E. coli* - **E. coli meningitis** is primarily a concern in **neonates** (birth to 1 month of age), often acquired during passage through the birth canal. - Its incidence significantly decreases after the neonatal period, making it a much less common cause in children aged 6 months to 2 years. *H. influenzae* - Before routine vaccination, **Haemophilus influenzae type b (Hib)** was the leading cause of bacterial meningitis in children under 5 years old. - The widespread use of the **Hib vaccine** has drastically reduced its incidence, making it a rare cause in vaccinated populations. *N. meningitidis* - **Neisseria meningitidis** (meningococcus) is a significant cause of bacterial meningitis, especially in older children, adolescents, and young adults. - While it can occur in children aged 6 months to 2 years, widespread **meningococcal vaccination** in many regions has reduced its overall prevalence, making *Pneumococcus* a more frequent cause in this specific vaccinated age group.

Question 1

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

Accepted Answer

Hepatitis A virus infection

Answer

Perinatal

Answer

Pin prick

Answer

Saliva exchange

Question 2

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

Accepted Answer

Prompt institution of antimicrobial therapy appears not to influence the incidence

Answer

It occurs rarely (less than 5% of cases)

Answer

Its onset often is late in the clinical course, after discontinuation of antimicrobial therapy

Answer

It occurs more commonly when Haemophilus influenza type B rather than Streptococcus pneumoniae is the causative organism of the meningitis

Question 3

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?

Accepted Answer

pneumonia

Answer

encephalitis

Answer

bronchitis

Answer

otitis media

Question 4

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

Accepted Answer

IV Ceftriaxone

Answer

IV Penicillin G

Answer

Oral Penicillin V

Answer

IV Cefotaxime

Question 5

Which of the following is Not characteristic of congenital Syphilis?

Accepted Answer

Ghon complex

Answer

Interstitial keratitis

Answer

Mulberry molars

Answer

Notched incisors

Question 6

Raspberry tongue is a feature of

Accepted Answer

Scarlet fever

Answer

Yellow fever

Answer

Mamba's disease

Answer

Katayama fever

Question 7

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

Accepted Answer

Influenza virus

Answer

Varicella (Chickenpox)

Answer

HIV

Answer

Measles virus

Question 8

A 4-year-old child presented with fever for 6 days, generalized rash and cervical lymphadenopathy with strawberry tongue. What could be the diagnosis?

Accepted Answer

Kawasaki disease

Answer

Kimura disease

Answer

Scarlet fever

Answer

Rosai-Dorfman disease

Question 9

The following age group is most severely affected by Rubella infection -

Accepted Answer

Unborn child

Answer

Young girls

Answer

Adolescent girls

Answer

Females aged 25-35 years

Question 10

Most common organism causing bacterial meningitis between 6 months and 2 years in vaccinated populations.

Accepted Answer

Pneumococcus

Answer

E. coli

Answer

H. influenzae

Answer

N. meningitidis

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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