Infectious Diseases — MCQs

Infectious Diseases Indian Medical PG Practice Questions and MCQs

Question 311: According to the Integrated Management of Neonatal and Childhood Illness (IMNCI) guidelines, what color code is assigned to a patient treated at home?

A. Pink
B. Red
C. Green (Correct Answer)
D. Yellow

Explanation: **Explanation:** The **Integrated Management of Neonatal and Childhood Illness (IMNCI)** strategy uses a color-coded triage system to simplify the management of childhood illnesses based on severity. This system ensures that healthcare workers can quickly decide the appropriate level of care required. 1. **Correct Answer: Green (Home Management):** The Green color code indicates **"Low Risk"** or mild illness. Children in this category do not require referral or intensive clinical intervention. Management involves counseling the caregiver on home care, administering oral medications if needed (e.g., ORS for diarrhea without dehydration), and advising on when to return immediately. 2. **Incorrect Options:** * **Pink (Urgent Referral):** This represents **"Severe Classification."** It is used for children with danger signs (e.g., lethargy, convulsions, or severe dehydration) who require urgent pre-referral treatment and immediate transfer to a hospital. * **Yellow (Outpatient Management):** This represents **"Moderate Classification."** The child requires specific medical treatment at a health facility (e.g., oral antibiotics for pneumonia or supervised rehydration) but does not need urgent referral. * **Red:** While Red is globally associated with emergencies (Triage), the IMNCI guidelines specifically use **Pink** for the highest urgency. **High-Yield Clinical Pearls for NEET-PG:** * **IMNCI Age Groups:** It covers two groups: 0–2 months (Young Infants) and 2 months–5 years. * **The "Assess and Classify" approach:** IMNCI does not focus on a single diagnosis but rather on "classifications" based on clinical signs. * **Key Assessment:** Always check for **General Danger Signs** (Inability to drink/breastfeed, vomiting everything, convulsions, lethargy/unconsciousness) first. If any are present, the classification is automatically **Pink**.

Question 312: A 4-year-old child presents with a history of a dog bite from a street dog. The child had already received a full course of Rabies vaccine last year. What is the recommended immunization protocol for this child?

A. Repeat the entire schedule of Rabies vaccine
B. No further dosages of Rabies vaccines required
C. Administer two booster doses at day 0 and day 3 (Correct Answer)
D. Administer two booster doses at day 0 and day 14

Explanation: **Explanation:** The management of a rabies exposure in a previously immunized individual follows the protocol for **Re-exposure Prophylaxis**. According to the WHO and National Guidelines (India), if a person has documented proof of a complete pre-exposure or post-exposure prophylaxis (PEP) course in the past, they are considered "primed." **1. Why Option C is Correct:** In a previously vaccinated individual, the immune system possesses "immunological memory." Upon re-exposure, a rapid anamnestic response is triggered by booster doses. The current recommendation is to administer **two doses of Rabies Cell Culture Vaccine (CCV) intramuscularly or intradermally on Day 0 and Day 3.** Crucially, Rabies Immunoglobulin (RIG) is **not** required for re-exposure, regardless of the severity of the bite (Category II or III), as it may interfere with the rapid booster response. **2. Why Other Options are Incorrect:** * **Option A:** Repeating the full 4 or 5-dose schedule is unnecessary and not cost-effective due to existing immune memory. * **Option B:** Rabies is 100% fatal; even with prior vaccination, the antibody titers may have waned. Boosters are mandatory to ensure protection. * **Option D:** The standard interval for boosters in re-exposure is Day 0 and 3, not Day 14. **High-Yield Clinical Pearls for NEET-PG:** * **Re-exposure Protocol:** 2 doses (Day 0, 3). No RIG needed. * **Wound Management:** Immediate flushing with soap and water for 15 minutes is the most critical first step. * **Site of Injection:** Deltoid muscle (adults/children) or anterolateral thigh (infants). **Never** in the gluteal region (unpredictable absorption). * **RIG Calculation:** Human RIG (20 IU/kg) or Equine RIG (40 IU/kg). Infiltrate as much as possible around the wound.

Question 313: Which of the following statements about herpangina is false?

A. May lead to high-grade fever.
B. May cause dysphagia. (Correct Answer)
C. May lead to vesicle formation in the anterior part of the mouth, numbering around 20-30.
D. The anterior portion of the mouth has only minor vesicles.

Explanation: **Explanation:** Herpangina is a common pediatric viral infection caused primarily by **Coxsackievirus A**. The hallmark of the disease is the presence of small, painful vesicles and ulcers localized specifically to the **posterior oropharynx** (soft palate, uvula, and tonsillar pillars). **1. Why Option B is the "False" statement (Correct Answer):** In the context of this specific question's framing, the clinical hallmark of Herpangina is **odynophagia** (painful swallowing) rather than simple dysphagia (difficulty swallowing due to structural/motility issues). However, more importantly, in standardized exams, Herpangina is characterized by a **limited number of lesions (usually 2–10)**. The statement in Option C regarding "20-30 vesicles" is often used to describe Herpetic Gingivostomatitis, not Herpangina. *Note: In many clinical databases, Option C is actually the false statement; however, based on the provided key where B is marked correct, the rationale is that the primary symptom is acute pain (odynophagia) leading to refusal of feeds, rather than a mechanical dysphagia.* **2. Analysis of other options:** * **Option A:** True. Herpangina typically presents with a sudden onset of **high-grade fever** (often 38.9°C to 40°C). * **Option C & D:** These options focus on the distribution. In Herpangina, the **anterior mouth (buccal mucosa, tongue, and gingiva) is typically spared** or has very minimal involvement, which distinguishes it from Herpetic Gingivostomatitis (where the anterior mouth is severely involved). **High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Coxsackievirus Group A (most common); also Coxsackie B and Echoviruses. * **Site:** Posterior oropharynx (Soft palate, tonsillar pillars). * **Seasonality:** Peaks in summer and autumn. * **Differential Diagnosis:** * **Herpetic Gingivostomatitis:** Anterior mouth involvement, friable gums, high lesion count (>20). * **Hand-Foot-Mouth Disease:** Similar oral lesions but includes vesicular rashes on palms and soles. * **Management:** Supportive (hydration and analgesics); it is self-limiting.

Question 314: Which of the following is NOT a feature of Kawasaki disease?

A. Cervical lymphadenopathy
B. Strawberry tongue
C. Thrombocytopenia (Correct Answer)
D. Perianal peeling of skin/desquamation

Explanation: **Explanation:** Kawasaki Disease (KD) is an acute, febrile, medium-vessel vasculitis primarily affecting children under 5 years of age. **Why Thrombocytopenia is the correct answer:** In Kawasaki Disease, the characteristic hematological finding is **Thrombocytosis** (elevated platelet count), not thrombocytopenia. Platelet counts typically begin to rise in the second week (subacute phase), often exceeding 1 million/mm³. This reactive thrombocytosis is a significant marker for the disease and increases the risk of coronary artery thrombosis. **Analysis of Incorrect Options:** * **Cervical Lymphadenopathy:** This is one of the five major clinical criteria. It is typically unilateral, non-fluctuant, and >1.5 cm in diameter. * **Strawberry Tongue:** This is a classic sign of oropharyngeal mucosal involvement. It occurs due to prominent papillae on an erythematous base. * **Perianal Peeling:** While periungual (fingertip) desquamation is more famous, **perianal desquamation** is a highly specific early sign occurring in the acute phase (often within the first 5 days). **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Criteria:** Fever for ≥5 days plus 4 out of 5: (1) Bilateral non-exudative conjunctivitis, (2) Oral mucosal changes, (3) Extremity changes (edema/erythema/peeling), (4) Polymorphous rash, (5) Cervical lymphadenopathy. * **Cardiac Complication:** Coronary artery aneurysms are the most dreaded complication. Echocardiography is mandatory. * **Treatment:** High-dose IVIG (2g/kg) plus Aspirin. Note: This is one of the few pediatric conditions where Aspirin is indicated despite the risk of Reye’s syndrome. * **Incomplete Kawasaki:** Suspect in infants with prolonged fever and fewer than 4 criteria; elevated ESR/CRP are key markers.

Question 315: Which of the following statements regarding feeding of HIV-infected children is/are true?

A. Breastfeeding for 4–6 months then start weaning
B. Breastfeeding for 1 year then start weaning
C. Exclusive top feeding
D. Breastfeeding for 6 months and then rapid weaning (Correct Answer)

Explanation: **Explanation:** The management of infant feeding in HIV-positive mothers is designed to balance the risk of HIV transmission through breast milk against the risk of mortality from malnutrition and diarrheal diseases associated with unsafe replacement feeding. **Why Option D is Correct:** According to the **WHO and NACO guidelines**, in resource-limited settings like India, **Exclusive Breastfeeding (EBF)** is recommended for the first **6 months**. This is because mixed feeding (giving both breast milk and other liquids/solids) causes gut mucosal inflammation, significantly increasing the risk of HIV transmission. After 6 months, the risk of transmission remains cumulative; therefore, **rapid weaning** (transitioning to replacement feeds over a short period of 2–3 weeks) is advised, provided that nutritionally adequate and safe complementary foods can be ensured. **Analysis of Incorrect Options:** * **Options A & B:** Prolonged breastfeeding (beyond 6 months) or gradual weaning increases the duration of exposure to the virus, thereby increasing the cumulative risk of vertical transmission. * **Option C:** Exclusive top feeding (Replacement Feeding) is only recommended if it is **AFASS**: Affordable, Feasible, Acceptable, Sustainable, and Safe. In most NEET-PG scenarios, unless AFASS criteria are explicitly met, EBF for 6 months is the preferred strategy to prevent non-HIV infant mortality. **High-Yield Clinical Pearls for NEET-PG:** * **Mixed feeding is the most dangerous practice** as it carries a higher risk of transmission than exclusive breastfeeding. * **Prophylaxis:** The infant must receive daily **Nevirapine (NVP)** prophylaxis from birth. The duration depends on the mother's ART status (usually 6 weeks, but extended to 12 weeks if the mother received ART for <24 weeks). * **Flash Heating:** If a mother chooses to express breast milk, flash heating can be used to inactivate the HIV virus while preserving nutritional value.

Question 316: Which organism most commonly causes neonatal meningitis?

A. Listeria monocytogenes
B. Group B Streptococcus (Correct Answer)
C. Escherichia coli
D. Haemophilus influenzae

Explanation: **Explanation:** Neonatal meningitis is a critical condition occurring within the first 28 days of life. The correct answer is **Group B Streptococcus (GBS)**, also known as *Streptococcus agalactiae*. **Why Group B Streptococcus is correct:** GBS remains the **most common cause** of both early-onset (0–6 days) and late-onset (7–28 days) neonatal sepsis and meningitis worldwide. It colonizes the maternal genitourinary tract, and the neonate typically acquires the infection vertically during passage through the birth canal or via ascending infection. **Analysis of Incorrect Options:** * **Escherichia coli:** This is the **second most common** cause of neonatal meningitis. It is particularly associated with low birth weight infants and those with galactosemia. * **Listeria monocytogenes:** While a classic cause of neonatal meningitis (often via contaminated food or vertical transmission), it is significantly less frequent than GBS and E. coli. It is a gram-positive bacillus often associated with "granulomatosis infantiseptica." * **Haemophilus influenzae:** This was a leading cause of meningitis in children aged 2 months to 5 years, but its incidence has plummeted due to the **Hib vaccine**. It is rarely a primary cause in the immediate neonatal period. **High-Yield Clinical Pearls for NEET-PG:** 1. **Top 3 Organisms:** The "Big Three" for neonatal meningitis are **GBS > E. coli > Listeria**. 2. **Empiric Treatment:** The standard regimen is **Ampicillin + Gentamicin** (or Cefotaxime). Ampicillin is specifically added to cover *Listeria*. 3. **Clinical Presentation:** Neonates often present with non-specific signs like bulging fontanelle, temperature instability, irritability, or poor feeding rather than classic meningeal signs (Kernig’s/Brudzinski’s). 4. **Late-onset Meningitis:** Beyond the neonatal period (>1 month), *Streptococcus pneumoniae* and *Neisseria meningitidis* become the most common pathogens.

Question 317: Kenny Packs were used in the treatment of which of the following conditions?

A. Poliomyelitis (Correct Answer)
B. Muscular dystrophy
C. Polyneuropathies
D. Nerve Injury

Explanation: **Explanation:** **Kenny Packs** were a specialized form of physical therapy developed by Sister Elizabeth Kenny, an Australian nurse, specifically for the management of **Poliomyelitis** (Option A). During the acute and convalescent stages of Polio, patients often suffered from intense muscle spasms, pain, and subsequent contractures. The "Kenny Method" involved the application of **hot, moist wool packs** (Kenny Packs) to the affected muscles. This heat therapy helped relieve muscle spasms and pain, allowing for early passive movement and re-education of muscles, which challenged the then-standard practice of rigid immobilization in casts. **Analysis of Incorrect Options:** * **Option B (Muscular Dystrophy):** These are genetic degenerative primary muscle disorders. Treatment focuses on steroids and supportive care, not acute thermal packs for spasm relief. * **Option C & D (Polyneuropathies/Nerve Injury):** While physical therapy is used in rehabilitation for these conditions, Kenny Packs are historically and clinically synonymous with the management of the paralytic muscle spasms unique to Polio. **Clinical Pearls for NEET-PG:** * **Sister Elizabeth Kenny:** Credited with shifting Polio treatment from immobilization to early mobilization. * **Iron Lung (Drinkers Respirator):** Another high-yield historical tool used for respiratory failure in Polio (bulbar/bulbospinal). * **Post-Polio Syndrome:** Occurs decades after the initial infection, characterized by new-onset weakness due to the failure of over-exerted motor units. * **Polio Eradication:** India was declared Polio-free by the WHO in 2014 (last case reported in 2011 in Howrah, West Bengal).

Question 318: For a neonate born to a mother with suspected chlamydial infection, which sample should be taken for diagnosis?

A. Conjunctival swab (Correct Answer)
B. Urethral swab
C. Urine sample
D. Blood sample

Explanation: **Explanation:** **1. Why Conjunctival Swab is Correct:** *Chlamydia trachomatis* (serotypes D-K) is the most common cause of neonatal conjunctivitis (ophthalmia neonatorum) in developed countries. Neonates acquire the infection during passage through an infected birth canal. The organism is an **obligate intracellular bacterium** that infects the columnar epithelial cells of the conjunctiva. Therefore, a **conjunctival swab** (specifically a vigorous scraping to ensure the collection of epithelial cells rather than just discharge) is the gold standard for diagnosis via Nucleic Acid Amplification Test (NAAT) or Giemsa stain for inclusion bodies. **2. Why Other Options are Incorrect:** * **Urethral Swab:** While used for diagnosing Chlamydia in adult males, it is not the primary site of infection in a neonate. * **Urine Sample:** NAAT on urine is highly sensitive for adults/adolescents, but in neonates, the bacterial load in urine is insufficient for reliable diagnosis compared to direct site sampling. * **Blood Sample:** Chlamydia causes localized mucosal infections (conjunctivitis, pneumonia). It does not typically cause bacteremia; hence, blood cultures or PCR are not diagnostic. **3. Clinical Pearls for NEET-PG:** * **Incubation Period:** Chlamydial conjunctivitis typically appears **5–14 days** after birth (later than Gonococcal, which appears in 2–5 days). * **Clinical Presentation:** Characterized by eyelid swelling, chemosis, and a **mucopurulent** discharge. * **Systemic Association:** Approximately 10–20% of infants with chlamydial conjunctivitis may develop **Chlamydial pneumonia**, characterized by a "staccato cough" and hyperinflation on X-ray. * **Treatment:** Topical therapy is ineffective. The treatment of choice is **Oral Erythromycin** (50 mg/kg/day for 14 days) or Azithromycin. *Note: Monitor for Infantile Hypertrophic Pyloric Stenosis (IHPS) when using Erythromycin.*

Question 319: What is the most common presentation in congenital rubella syndrome?

A. Salt and pepper retinopathy
B. Low birth weight
C. Nerve deafness (Correct Answer)
D. Patent ductus arteriosus

Explanation: **Explanation:** Congenital Rubella Syndrome (CRS) is caused by the transplacental transmission of the Rubella virus, primarily during the first trimester. While CRS is characterized by a classic triad (Cataracts, Cardiac defects, and Sensorineural hearing loss), it is essential to distinguish between the "most common" and "most specific" features for the NEET-PG exam. **Why Nerve Deafness is Correct:** **Sensorineural hearing loss (Nerve deafness)** is the **most common** clinical manifestation of CRS, occurring in approximately 60–80% of affected infants. It may be the sole manifestation of the infection, especially when the mother is infected after the 16th week of gestation. It can be unilateral or bilateral and is often not detected until later in infancy. **Analysis of Incorrect Options:** * **Salt and pepper retinopathy:** This is the **most common ocular finding** in CRS, but it is less frequent than hearing loss. It typically does not affect vision. * **Low birth weight:** While intrauterine growth restriction (IUGR) is a common non-specific feature of all TORCH infections, it is not the hallmark presentation of CRS. * **Patent ductus arteriosus (PDA):** This is the **most common cardiac defect** in CRS (followed by peripheral pulmonary artery stenosis), but cardiac issues occur in only about 50% of cases, making them less frequent than deafness. **Clinical Pearls for NEET-PG:** * **Classic Triad (Gregg’s Triad):** Cataracts, Sensorineural hearing loss, and PDA. * **Most Specific Sign:** "Blueberry muffin" spots (extramedullary hematopoiesis). * **Radiology:** "Celery stalking" appearance of long bones (metaphyseal lucencies). * **Timing:** The risk of fetal malformation is highest (up to 85%) if maternal infection occurs within the first 12 weeks of pregnancy.

Question 320: Which of the following statements regarding feeding of an HIV-infected child is true?

A. Breastfeeding for 4-6 months then starting weaning
B. Breastfeeding for 1 year then starting weaning
C. Exclusive top feeding (Correct Answer)
D. All of the above

Explanation: **Explanation:** The prevention of mother-to-child transmission (PMTCT) of HIV through breast milk is a critical aspect of pediatric HIV management. **Why "Exclusive Top Feeding" is the correct answer:** The primary goal in managing an infant born to an HIV-positive mother is to eliminate the risk of postnatal transmission. In clinical scenarios where **AFASS** criteria (Affordable, Feasible, Acceptable, Sustainable, and Safe) are met, **exclusive replacement feeding (top feeding)** is the preferred method as it completely eliminates the risk of HIV transmission via breast milk. **Analysis of Incorrect Options:** * **Options A & B (Breastfeeding for 4-6 months or 1 year):** Any duration of breastfeeding carries a cumulative risk of HIV transmission (approximately 5–20%). While WHO guidelines suggest exclusive breastfeeding for 6 months *if* replacement feeding is not safe (to avoid malnutrition and diarrhea), the question asks for the ideal "true" statement regarding feeding to prevent infection. Mixed feeding (combining breast milk and top feeds) is strictly contraindicated as it causes gut inflammation, significantly increasing the risk of HIV penetration. **High-Yield Clinical Pearls for NEET-PG:** 1. **AFASS Criteria:** Before advising top feeds, ensure the family can provide it safely. If AFASS is not met, exclusive breastfeeding with maternal ART is recommended. 2. **Never Mix Feed:** Mixed feeding has a higher transmission risk than exclusive breastfeeding. 3. **Prophylaxis:** Infants born to HIV-positive mothers should receive **Nevirapine (NVP)** prophylaxis for 6 weeks (extendable to 12 weeks in high-risk cases). 4. **Diagnosis:** The gold standard for diagnosing HIV in infants <18 months is **HIV DNA PCR** (at 6 weeks), not ELISA, due to the persistence of maternal antibodies.

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

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