Infectious Diseases Practice Questions

Q: A 7-year-old girl presents with a sore throat, fever, and a strawberry tongue. Which of the following conditions is most likely?

Scarlet fever. ***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.

Q: A 7-year-old boy presents with fever, sore throat, and painful swelling of the parotid glands. What is the most likely diagnosis?

Mumps. ***Correct Answer: Mumps*** - **Fever**, **sore throat**, and **painful swelling of the parotid glands** are classic symptoms of mumps, a viral infection caused by the mumps virus (paramyxovirus). - Mumps primarily targets the **salivary glands**, especially the parotid glands, leading to characteristic bilateral facial swelling. - The combination of constitutional symptoms with parotid involvement is pathognomonic for mumps. *Incorrect: Tonsillitis* - Characterized by **inflamed and swollen tonsils**, often with exudate, leading to severe sore throat and difficulty swallowing. - **Parotid gland swelling** is not a typical feature of tonsillitis. - Lymph node enlargement may occur but differs from parotid enlargement. *Incorrect: Epiglottitis* - A serious bacterial infection causing inflammation and swelling of the **epiglottis**, which can rapidly obstruct the airway. - Symptoms include **stridor**, **drooling**, **tripod positioning**, and **difficulty breathing**, not parotid swelling. - This is a medical emergency requiring immediate airway management. *Incorrect: Lymphadenitis* - Refers to inflammation of the **lymph nodes**, which can cause localized swelling and tenderness. - While cervical lymph nodes might be swollen with a sore throat, this presents as distinct nodular swelling along lymph node chains. - Does not involve the specific, bilateral swelling of the **parotid glands** as seen with mumps.

Q: Which of the following is a criterion for clinical Stage II of AIDS in children?

Hepatosplenomegaly. ***Hepatosplenomegaly*** - **Unexplained persistent hepatosplenomegaly** is a defining criterion for WHO clinical **Stage II** of pediatric HIV/AIDS - This stage reflects moderate immune deterioration with clinical manifestations beyond the asymptomatic or mild Stage I findings - Other Stage II criteria include herpes zoster, recurrent upper respiratory tract infections, and fungal nail infections *Oesophageal candidiasis* - **Oesophageal candidiasis** is a severe opportunistic infection classified under **Stage IV** (severe HIV disease) - This indicates advanced immunosuppression with severe AIDS-defining conditions - Stage IV includes other severe infections like cryptococcal meningitis, toxoplasmosis of the brain, and extrapulmonary tuberculosis *Oral candidiasis* - **Oral candidiasis** (persistent or recurrent beyond 2 months of age) is classified under **Stage II** when it meets specific WHO criteria - However, in this context, **hepatosplenomegaly** is the more definitive and commonly emphasized Stage II criterion being tested - Oral thrush in young infants (<2 months) may be physiological and doesn't indicate HIV staging *Lymphadenopathy* - **Persistent generalized lymphadenopathy (PGL)** is a characteristic finding in **Stage I** (asymptomatic or mild HIV disease) - PGL alone represents minimal immune dysfunction and is one of the earliest clinical manifestations - Stage II requires more specific symptoms indicating moderate immunosuppression beyond lymphadenopathy alone

Q: At what age should the rotavirus vaccine not be initiated to prevent complications?

15 weeks. ***15 weeks*** - The first dose of the **rotavirus vaccine** should be administered **before 15 weeks of age** (specifically, no later than 14 weeks and 6 days). - Initiating the vaccine **at or after 15 weeks of age** is **not recommended** due to an increased risk of **intussusception**, a serious complication involving telescoping of the intestine. - The risk of intussusception increases with age, particularly when the first dose is given after the recommended window. *14 weeks* - This age is **within the acceptable window** for initiating the rotavirus vaccine series. - The first dose can be given up to **14 weeks and 6 days of age**, so 14 weeks is still appropriate for vaccine initiation. *6 weeks* - This is the **earliest recommended age** for the first dose of the rotavirus vaccine. - The vaccine is typically given at **6, 10, and 14 weeks** (or 2, 4, and 6 months) depending on the national immunization schedule and vaccine brand. *10 weeks* - This age is well within the **recommended window** for rotavirus vaccine administration. - This is often the timing for the second dose in many vaccination schedules, but the first dose can also be safely given at this age.

Q: An infant has fever, one episode of febrile convulsions, and is admitted for observation. The fever then subsided and was followed by a rash on the abdomen and chest, which is maculopapular and erythematous. What is the cause?

Roseola infantum (Sixth disease). ***Roseola infantum (Sixth disease)*** - Characterized by **high fever** (often a trigger for **febrile seizures**) followed by an **erythematous, maculopapular rash** that appears as the fever subsides. - This clinical presentation is highly suggestive of **Roseola infantum**, caused by **Human Herpesvirus 6 (HHV-6)** or sometimes **HHV-7**, primarily affecting infants and young children. *Measles (Rubeola)* - Measles rash typically presents as a **maculopapular rash** that starts on the **face** and spreads downwards, appearing **during the fever**'s peak, not after it subsides. - Classic symptoms also include **Koplik spots** (small white spots inside the mouth) and the **three Cs: cough, coryza, and conjunctivitis**, which are not mentioned. *Typhoid fever (Salmonella Typhi infection)* - Typhoid fever is characterized by a **prolonged high fever**, **bradycardia**, and typically a **rose spot rash** (small, faint, salmon-colored macules) primarily on the trunk, appearing later in the illness. - Febrile convulsions are less common, and the timing and nature of the rash do not match the description provided. *Dengue fever (DENV infection)* - Dengue fever presents with **high fever**, severe headache, retro-orbital pain, muscle and joint pains (breakbone fever), and often a **maculopapular or petechial rash** that can appear around the time the fever starts to drop, but usually accompanies other severe symptoms. - While a rash can occur, the distinct pattern of fever followed by a rash as the fever resolves, with febrile convulsions without other characteristic dengue symptoms, makes it less likely.

Q: Which of the following statements about Koplik spots is true?

All of the options.. All of the options. - Koplik spots are pathognomonic of measles, meaning their presence is a definitive indicator of the disease [1]. - They typically appear as tiny, white spots on an erythematous base on the buccal mucosa, often opposite the molars [1]. Pathognomonic of measles. - While Koplik spots are a hallmark sign of measles, stating this is true alone doesn't encompass all true aspects for this question [1]. - Their presence, however, is a strong diagnostic indicator of rubeola. Present on buccal mucosa opposite the molars. - This is a correct description of their typical location, but not a complete answer to the question "Which of the following statements about Koplik spots is true?" if other options also hold true [1]. - These spots are found on the mucous membrane lining the inside of the cheeks [1]. Not always present. - Koplik spots are transient and may not be present throughout the entire course of measles, particularly if a patient is seen later in the disease [1]. - They also can be missed if not specifically looked for or if they are very few in number.

Q: What is the appropriate management for a child who has been bitten by a cat?

All of the options are true. ***All of the options are true*** - Comprehensive management of a cat bite requires **multiple interventions** addressing infection prevention, rabies prophylaxis, and immediate wound care. - Cat bites have a high infection rate (30-50%) due to deep puncture wounds from sharp teeth that inoculate bacteria like *Pasteurella multocida*, *Streptococcus*, and *Staphylococcus* deep into tissues. *Administer prophylactic antibiotics to prevent infection* - **Prophylactic antibiotics** are recommended for cat bites due to the high risk of infection (particularly *Pasteurella multocida*). - First-line therapy is typically **amoxicillin-clavulanate** (Augmentin), which covers the most common pathogens. - Deep puncture wounds, bites to hands/feet, immunocompromised patients, and delayed presentation warrant antibiotic prophylaxis. *Rabies vaccination may be necessary* - **Rabies post-exposure prophylaxis (PEP)** is crucial if the cat is unvaccinated, a stray, or its vaccination status is unknown. - Rabies is nearly 100% fatal once symptoms appear, making prophylaxis essential in high-risk situations. - The decision depends on local rabies prevalence and assessment of the animal's behavior and health status. *Thoroughly clean the wound* - **Immediate and copious irrigation** with soap and water or saline is the most important initial step in management. - This reduces bacterial load significantly and decreases infection risk. - Most cat bite wounds should be left open (not sutured) due to high infection risk, unless on the face for cosmetic reasons.

Q: Which of the following statements about rashes in children is incorrect?

Varicella - typically appears on day 1. ***Varicella - typically appears on day 1*** - This statement is incorrect because the typical rash of **varicella** (**chickenpox**) usually appears on **day 2 or 3** of the illness, following a prodrome of fever and malaise. - The rash begins as macules, quickly progressing to papules, vesicles, and then crusts, often in a **centrifugal distribution**. *Typhus - typically appears on day 5* - This statement is correct. The rash of **epidemic typhus** (caused by *Rickettsia prowazekii*) typically appears around **day 5 or 6** following the onset of fever. - It usually starts on the trunk and spreads peripherally, often sparing the face, palms, and soles. *Typhoid - typically appears on day 5* - This statement is correct. The classic "rose spots" rash of **typhoid fever** (caused by *Salmonella Typhi*) typically appears around **day 5 to 7** of the illness. - These are faint, salmon-colored, blanching maculopapular lesions, usually found on the trunk and chest. *Measles - typically appears on day 4* - This statement is correct. The characteristic **maculopapular rash of measles** (rubeola) typically appears around **day 3 or 4** after the onset of the prodromal symptoms (fever, cough, coryza, conjunctivitis). - The rash starts on the face and behind the ears, then spreads cephalocaudally over the body.

Question 1

A 7-year-old girl presents with a sore throat, fever, and a strawberry tongue. Which of the following conditions is most likely?

Accepted Answer

Scarlet fever

Answer

Kawasaki disease

Answer

Infectious mononucleosis

Answer

Hand-foot-and-mouth disease

Question 2

A 2-month-old infant presents with poor feeding, irritability, and a bulging anterior fontanelle. What is the most likely diagnosis?

Accepted Answer

Meningitis

Answer

Hydrocephalus

Answer

Intraventricular Hemorrhage

Answer

Cerebral Palsy

Question 3

A 7-year-old boy presents with fever, sore throat, and painful swelling of the parotid glands. What is the most likely diagnosis?

Accepted Answer

Mumps

Answer

Tonsillitis

Answer

Epiglottitis

Answer

Lymphadenitis

Question 4

Which of the following is a criterion for clinical Stage II of AIDS in children?

Accepted Answer

Hepatosplenomegaly

Answer

Oesophageal candidiasis

Answer

Lymphadenopathy

Answer

Oral candidiasis

Question 5

At what age should the rotavirus vaccine not be initiated to prevent complications?

Accepted Answer

15 weeks

Answer

14 weeks

Answer

6 weeks

Answer

10 weeks

Question 6

Which statement regarding the administration of vaccines is correct?

Accepted Answer

Live vaccines should not be administered for 12 weeks if immunoglobulin has been given.

Answer

Live and killed vaccines can be administered together.

Answer

Immunoglobulin should not be given for at least 6 weeks when a live vaccine is administered.

Answer

Two live vaccines can be given together if they are compatible.

Question 7

An infant has fever, one episode of febrile convulsions, and is admitted for observation. The fever then subsided and was followed by a rash on the abdomen and chest, which is maculopapular and erythematous. What is the cause?

Accepted Answer

Roseola infantum (Sixth disease)

Answer

Measles (Rubeola)

Answer

Typhoid fever (Salmonella Typhi infection)

Answer

Dengue fever (DENV infection)

Question 8

Which of the following statements about Koplik spots is true?

Accepted Answer

All of the options.

Answer

Pathognomonic of measles.

Answer

Present on buccal mucosa opposite the molars.

Answer

Not always present.

Question 9

What is the appropriate management for a child who has been bitten by a cat?

Accepted Answer

All of the options are true

Answer

Administer prophylactic antibiotics to prevent infection

Answer

Rabies vaccination may be necessary

Answer

Thoroughly clean the wound

Question 10

Which of the following statements about rashes in children is incorrect?

Accepted Answer

Varicella - typically appears on day 1

Answer

Typhoid - typically appears on day 5

Answer

Typhus - typically appears on day 5

Answer

Measles - typically appears on day 4

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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