Infectious Diseases Practice Questions

Q: Sixth disease is?

Exanthema subitum. ***Exanthema subitum*** - Exanthema subitum, also known as **Roseola infantum** or **sixth disease**, is a common childhood illness caused by human herpesvirus 6 (HHV-6) or less commonly HHV-7. - It is characterized by **3-5 days of high fever** followed by the abrupt appearance of a **maculopapular rash** once the fever subsides. *Erythema nodosum* - **Erythema nodosum** presents as tender, red nodules, typically on the shins, and is a type of **panniculitis** (inflammation of subcutaneous fat). - It is often associated with systemic diseases, infections (e.g., strep throat, tuberculosis), drugs, or inflammatory bowel disease, rather than being a primary childhood viral exanthem. *Erythema marginatum* - **Erythema marginatum** is a rare, transient, and non-pruritic rash with **serpiginous (snake-like) borders** that is a specific hallmark of **acute rheumatic fever**. - It is not a generalized viral exanthem and does not follow a typical febrile phase like sixth disease. *Erythema Infectiosum* - **Erythema infectiosum**, also known as **fifth disease**, is caused by **parvovirus B19** and is characterized by a "slapped cheek" rash on the face followed by a lacy rash on the trunk and extremities. - While it's a common childhood exanthem, it's distinct from sixth disease in its causative agent and characteristic rash pattern.

Q: A 6-year-old child presents with hepatosplenomegaly and generalized lymphadenopathy along with fever. The child developed a rash after being administered ampicillin. What could be the possible diagnosis?

Infectious mononucleosis. ***Infectious mononucleosis*** - The combination of **hepatosplenomegaly**, **generalized lymphadenopathy**, and fever in a child is highly suggestive of infectious mononucleosis, typically caused by the **Epstein-Barr virus (EBV)**. - A characteristic feature is the development of a **maculopapular rash** following the administration of ampicillin or amoxicillin. *Kawasaki disease* - Characterized by **fever**, generalized rash, lymphadenopathy, and mucocutaneous inflammation, but typically does not involve significant **hepatosplenomegaly**. - The rash in Kawasaki disease is not typically triggered by **ampicillin**. *Scarlet fever* - Caused by a **Streptococcus pyogenes** infection and presents with a characteristic **sandpaper-like rash**, **strawberry tongue**, and fever. - It usually does not involve significant **hepatosplenomegaly** or a rash specifically induced by ampicillin. *HIV infection* - While HIV can cause **generalized lymphadenopathy** and **hepatosplenomegaly**, especially in children, the sudden onset of a rash specifically after ampicillin administration is not a hallmark of acute or chronic HIV infection. - Other opportunistic infections and **growth failure** would likely be present in advanced HIV.

Q: Koplik spots are seen in?

Measles. ***Measles*** - **Koplik spots** are pathognomonic rash that appears as small, white spots with a bluish-white center on an erythematous base on the **buccal mucosa** opposite the second molars. - They typically appear 2-3 days before the onset of the characteristic maculopapular rash, during the **prodromal phase** of measles (rubeola). *Rubella* - Rubella, or **German measles**, presents with a milder rash, **lymphadenopathy**, and mild fever. - It does not cause Koplik spots; instead, **Forchheimer spots** (petechiae on the soft palate) may be seen, but these are less specific. *Mumps* - Mumps is characterized primarily by **parotitis** (swelling of the salivary glands), fever, and headache. - It does not present with Koplik spots or any characteristic oral mucosal lesions. *Varicella* - Varicella, or **chickenpox**, is characterized by a **vesicular rash** that progresses from macules to papules to vesicles to crusts, appearing in crops. - It does not involve Koplik spots; the rash is typically generalized and pruritic.

Q: Most common cause of post-measles death?

Pneumonia. ***Pneumonia*** - **Pneumonia**, particularly secondary bacterial pneumonia, is the **most common cause of death** in children following a measles infection. - Measles causes **immune suppression** and damage to the respiratory epithelium, making individuals vulnerable to severe respiratory infections. *SSPE* - **Subacute sclerosing panencephalitis (SSPE)** is a rare, fatal, late complication of measles, occurring years after the initial infection. - While always fatal, its rarity means it is not the most common cause of overall measles-related mortality. *Myocarditis* - **Myocarditis**, inflammation of the heart muscle, can be a rare complication of measles, but it is not the leading cause of death. - Cardiac complications are less frequently observed as the primary cause of death compared to respiratory infections. *Diarrhea* - **Diarrhea** is a common complication of measles, especially in malnourished children, and can contribute to mortality due to **dehydration** and electrolyte imbalances. - However, severe respiratory complications like pneumonia are still responsible for a higher proportion of measles-related deaths.

Q: According to WHO clinical staging of HIV in children oral hairy leukoplakia belongs to which clinical stages?

Clinical stage 2. ***Clinical stage 2*** - **Oral hairy leukoplakia** is classified under WHO clinical stage 2 for HIV infection, representing mild symptomatic disease with moderate immune compromise. - Stage 2 includes conditions such as **angular cheilitis**, **papular pruritic eruptions**, **recurrent oral ulcerations**, **herpes zoster**, **lineal gingival erythema**, and **recurrent upper respiratory tract infections**. - **Note:** Oral hairy leukoplakia is **rare in children** and is more commonly seen in adults with HIV; it is caused by **Epstein-Barr virus** reactivation. *Clinical stage 1* - This stage includes **asymptomatic** HIV infection or **persistent generalized lymphadenopathy**. - Stage 1 represents minimal or no immune compromise with no clinical manifestations requiring intervention. *Clinical stage 3* - Clinical stage 3 represents **advanced symptomatic disease** with conditions like **unexplained severe malnutrition**, **unexplained persistent diarrhea**, **oral candidiasis**, **pulmonary tuberculosis**, and **severe recurrent bacterial pneumonia**. - These conditions indicate more severe immunodeficiency than oral hairy leukoplakia. *Clinical stage 4* - Clinical stage 4 represents **severe HIV disease** with AIDS-defining illnesses such as **Pneumocystis jirovecii pneumonia**, **extrapulmonary tuberculosis**, **Kaposi's sarcoma**, **HIV encephalopathy**, **CMV retinitis**, and **disseminated mycobacterial infections**. - Stage 4 conditions are life-threatening and indicate severe immunosuppression.

Q: Most common complication of mumps in children:

Aseptic meningitis. ***Aseptic meningitis*** - **Aseptic meningitis** is the most frequent complication of mumps, occurring in approximately 10-30% of cases, primarily in children. - It usually presents with mild symptoms like **headache**, **fever**, and **nuchal rigidity** and typically resolves without specific treatment or long-term sequelae. - This is a benign, self-limiting condition that represents **CNS involvement** during mumps infection. *Myocarditis* - Myocarditis can occur as a complication of mumps, but it is **relatively rare** and much less common than aseptic meningitis. - While it can be serious, it is not considered the most common complication in children. *Orchitis* - Orchitis (inflammation of the testicles) is a well-known complication of mumps, but it primarily affects **post-pubertal males** and is uncommon in prepubertal children. - In the pediatric age group specifically, it is **less common than aseptic meningitis**. - Can lead to testicular atrophy and potential fertility issues in adults. *Pancreatitis* - Pancreatitis is a known but **less frequent complication**, occurring in about 2-5% of mumps cases. - While it can cause abdominal pain and elevated serum amylase, it is not the most common complication of mumps in children.

Q: Most common cause of HIV infection in infant is –

Intrapartum transmission. ***Intrapartum transmission*** - **Intrapartum transmission** (during labor and delivery) accounts for approximately **60-70% of mother-to-child HIV transmission** without interventions, making it the most common single route of HIV infection in infants. - This occurs when the infant is exposed to maternal blood and bodily fluids during the birth process. - The risk is highest during vaginal delivery, though transmission can occur with cesarean section as well. *Transplacental (in utero)* - **Transplacental transmission** occurs during pregnancy when the virus crosses the placental barrier. - This accounts for approximately **25-30% of mother-to-child transmission** without interventions. - While significant, it is less common than transmission during delivery. *Breast milk* - **Breastfeeding** can transmit HIV from mother to infant and accounts for approximately **10-15% of MTCT** in the absence of antiretroviral therapy. - Postnatal transmission through breastfeeding is an important but less common route compared to transmission during the birthing process. - The risk is cumulative over the duration of breastfeeding. *Blood transfusion* - **Blood transfusion** was a significant cause of HIV transmission in the past before routine screening. - With modern blood safety measures and universal screening of blood products, this route has become extremely rare. - This is no longer a common cause of HIV infection in infants in countries with proper blood screening protocols.

Q: Which of the following is true regarding Typhoid in children -

Mild splenomegaly is usual. ***Mild splenomegaly is usual*** - **Splenomegaly** is a common finding in children with typhoid fever, often mild to moderate. - The spleen may enlarge due to bacterial dissemination and the body's immune response to the infection. *Urine culture is positive in 4 to 6 days* - **Urine culture** typically becomes positive much later in the course of typhoid fever, usually after the first week or even later, once bacteria have disseminated more widely. - **Blood culture** is the most reliable diagnostic test in the first week of illness. *Leukocytosis is characteristic* - **Leukopenia** (low white blood cell count), sometimes with relative lymphocytosis, is characteristic of typhoid fever, especially in the early stages. - **Leukocytosis** (high white blood cell count) is atypical and may suggest a different infection or a complication. *Encephalitis is common* - **Encephalopathy** (altered mental status, confusion) can occur in severe cases of typhoid fever, sometimes referred to as "typhoid encephalopathy." - True **encephalitis** (inflammation of the brain parenchyma) is a less common neurological complication and is not characteristic for every case.

Q: All of the following are features of poliomyelitis except –

Progressive course. Progressive course - Poliomyelitis typically presents with an **acute onset of flaccid paralysis**, not a progressive worsening over a long period, distinguishing it from conditions like amyotrophic lateral sclerosis [1]. - While post-polio syndrome can have a progressive course years after the initial infection, the primary disease itself is characterized by an acute phase followed by a stable or improving state [1]. *Intact sensation* - Poliomyelitis specifically affects the **anterior horn cells** of the spinal cord, leading to motor weakness and paralysis. - Sensory pathways are generally unaffected, so patients with polio typically retain **intact sensation**. [1] *Acute onset* - The classic presentation of paralytic poliomyelitis is an **acute development of muscle weakness** and paralysis, often reaching its peak within days. - This acute onset is a hallmark feature of the disease's paralytic forms [1]. *Febrile onset* - Poliomyelitis often begins with a **prodromal febrile illness**, characterized by fever, headache, malaise, and sometimes gastrointestinal symptoms. - This initial febrile phase precedes the onset of neurological symptoms in paralytic cases.

Q: An appropriate single antibiotic for the empiric treatment of presumed bacterial meningitis in a six month old child would be:

Cefotaxime. ***Cefotaxime*** - As a **third-generation cephalosporin**, cefotaxime has excellent penetration into the **cerebrospinal fluid (CSF)** and provides broad-spectrum coverage against common bacterial meningitis pathogens in young children, including *Streptococcus pneumoniae*, *Neisseria meningitidis*, and *Haemophilus influenzae*. - In a 6-month-old child, cefotaxime is an excellent choice for empiric therapy. While both cefotaxime and ceftriaxone are appropriate at this age, cefotaxime is specifically preferred over ceftriaxone in **neonates younger than 28 days** due to concerns about biliary pseudolithiasis and bilirubin displacement, which can worsen jaundice and increase the risk of kernicterus. *Ampicillin* - While effective against *Listeria monocytogenes* (particularly important in neonates and infants <3 months) and Group B *Streptococcus*, ampicillin provides **insufficient coverage** for many other common causes of bacterial meningitis in this age group, particularly penicillin-resistant *Streptococcus pneumoniae* and *Haemophilus influenzae*. - Its use alone as empiric therapy for bacterial meningitis in a 6-month-old would be inadequate, often warranting combination therapy with a third-generation cephalosporin in younger infants. *Cefadroxil* - Cefadroxil is a **first-generation cephalosporin** primarily used for skin, soft tissue, and urinary tract infections. - It has **poor penetration into the CSF** and therefore is not an appropriate choice for treating meningitis. *Cefuroxime* - Cefuroxime is a **second-generation cephalosporin** with limited activity against *Streptococcus pneumoniae* and certain **Gram-negative bacteria** compared to third-generation cephalosporins. - While it has some central nervous system penetration, its efficacy is **inferior to third-generation cephalosporins** like cefotaxime or ceftriaxone for treating bacterial meningitis, especially considering the potential for resistant strains.

Question 1

Sixth disease is?

Accepted Answer

Exanthema subitum

Answer

Erythema nodosum

Answer

Erythema marginatum

Answer

Erythema Infectiosum

Question 2

A 6-year-old child presents with hepatosplenomegaly and generalized lymphadenopathy along with fever. The child developed a rash after being administered ampicillin. What could be the possible diagnosis?

Accepted Answer

Infectious mononucleosis

Answer

Kawasaki disease

Answer

Scarlet fever

Answer

HIV infection

Question 3

Koplik spots are seen in?

Accepted Answer

Measles

Answer

Rubella

Answer

Mumps

Answer

Varicella

Question 4

Most common cause of post-measles death?

Accepted Answer

Pneumonia

Answer

SSPE

Answer

Myocarditis

Answer

Diarrhea

Question 5

According to WHO clinical staging of HIV in children oral hairy leukoplakia belongs to which clinical stages?

Accepted Answer

Clinical stage 2

Answer

Clinical stage 1

Answer

Clinical stage 3

Answer

Clinical stage 4

Question 6

Most common complication of mumps in children:

Accepted Answer

Aseptic meningitis

Answer

Myocarditis

Answer

Pancreatitis

Answer

Orchitis

Question 7

Most common cause of HIV infection in infant is –

Accepted Answer

Intrapartum transmission

Answer

Transplacental

Answer

Breast milk

Answer

Blood transfusion

Question 8

Which of the following is true regarding Typhoid in children -

Accepted Answer

Mild splenomegaly is usual

Answer

Urine culture is positive in 4 to 6 days

Answer

Leukocytosis is characteristic

Answer

Encephalitis is common

Question 9

All of the following are features of poliomyelitis except –

Accepted Answer

Progressive course

Answer

Intact sensation

Answer

Acute onset

Answer

Febrile onset

Question 10

An appropriate single antibiotic for the empiric treatment of presumed bacterial meningitis in a six month old child would be:

Accepted Answer

Cefotaxime

Answer

Ampicillin

Answer

Cefadroxil

Answer

Cefuroxime

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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