Infectious Diseases Practice Questions

Q: Which of the following is the least common complication of measles?

Subacute sclerosing panencephalitis (SSPE). **Explanation:** The correct answer is **D. Subacute sclerosing panencephalitis (SSPE)**. Measles is associated with several complications, ranging from very common to extremely rare. The distinction between these options lies in their **frequency vs. severity**. 1. **Why SSPE is the correct answer:** SSPE is a progressive, fatal neurodegenerative disease caused by a persistent infection with a mutant measles virus. While devastating, it is the **least common** complication, occurring in approximately **1 in 10,000 to 1 in 100,000** cases. It typically manifests 7–10 years after the initial measles infection. 2. **Why other options are incorrect:** * **Diarrhea (Option A):** This is the **most common** complication of measles overall (occurring in ~8% of cases), particularly in malnourished children. * **Otitis Media (Option C):** This is the most common **bacterial** complication of measles. * **Pneumonia (Option B):** This is the most common cause of **measles-related death** in children. It can be caused by the virus itself (Hecht’s giant cell pneumonia) or secondary bacterial infections. **NEET-PG High-Yield Pearls:** * **Most common complication:** Diarrhea. * **Most common cause of death:** Pneumonia. * **Most common CNS complication:** Post-measles encephalitis (1 in 1,000). * **Vitamin A:** Supplementation reduces mortality and the severity of complications (given as two doses 24 hours apart). * **SSPE Diagnosis:** Look for high titers of anti-measles antibodies in the CSF and characteristic **periodic complexes** on EEG.

Q: Which of the following is false regarding measles?

Nikolsky's sign. **Explanation:** The correct answer is **D. Nikolsky’s sign**. **Nikolsky’s sign** is a clinical finding where the top layers of the skin slip away from the lower layers when rubbed, indicating a loss of intercellular adhesion (acantholysis). This sign is characteristic of **Pemphigus vulgaris** and **Staphylococcal Scalded Skin Syndrome (SSSS)**. It is **not** a feature of measles, which is a viral exanthematous illness that does not involve bullae or skin sloughing. **Analysis of other options:** * **A. Koplik’s spots:** These are the pathognomonic sign of measles. They are small, bluish-white grains of sand on an erythematous base, typically found on the buccal mucosa opposite the lower second molars during the prodromal phase. * **B. Maculopapular skin rash:** This is the hallmark of the eruptive phase. The rash typically begins behind the ears at the hairline, spreads cranio-caudally (downward), and disappears in the same order, often leaving behind brownish discoloration or fine desquamation. * **C. Fever and malaise:** These are common prodromal symptoms. Measles is characterized by high-grade fever and the "3 Cs": Cough, Coryza, and Conjunctivitis. **High-Yield Clinical Pearls for NEET-PG:** * **Infectivity:** Most infectious during the prodromal period (4 days before to 4 days after the appearance of the rash). * **Vitamin A:** Supplementation is recommended for all children with measles to reduce the risk of complications like blindness and severe pneumonia. * **Subacute Sclerosing Panencephalitis (SSPE):** A rare, delayed, and fatal neurological complication occurring years after the initial infection. * **Modified Measles:** Occurs in partially immune individuals; the incubation period is longer, and symptoms are milder.

Q: A 5-year-old child has had eight episodes of acute otitis media in 6 months and has difficulty resolving the effusions between infections. What is the most effective management strategy?

Adenoidectomy. **Explanation:** The core issue in this clinical scenario is **Recurrent Acute Otitis Media (RAOM)** with persistent **Otitis Media with Effusion (OME)**. The frequency of infections (8 episodes in 6 months) and the failure to resolve effusions suggest a chronic underlying mechanical or infectious focus. **Why Adenoidectomy is the Correct Answer:** The adenoids play a dual role in the pathogenesis of recurrent ear infections. First, **adenoid hypertrophy** can mechanically obstruct the Eustachian tube orifice, leading to negative middle ear pressure and effusion. Second, and more importantly, the adenoids act as a **bacterial reservoir (biofilm)** for otopathogens like *S. pneumoniae* and *H. influenzae*. Removing the adenoids eliminates this source of infection and improves Eustachian tube function, making it the most effective long-term management strategy for refractory cases. **Analysis of Incorrect Options:** * **Option A:** Treating each infection reactively fails to address the anatomical/pathological predisposition, leading to further recurrence and potential hearing loss. * **Option B:** While ventilating tubes (myringotomy) help drain fluid and equalize pressure, they do not address the source of infection (the adenoids). In children over 4 years with recurrent issues, adenoidectomy is often preferred or combined with tubes. * **Option C:** Prophylactic antibiotics are no longer recommended as a primary strategy due to the high risk of antibiotic resistance and limited long-term efficacy compared to surgical intervention. **Clinical Pearls for NEET-PG:** * **Definition of RAOM:** $\ge$ 3 episodes in 6 months or $\ge$ 4 episodes in 12 months. * **Indications for Adenoidectomy:** Recurrent OM (especially if >4 years old), chronic sinusitis, and obstructive sleep apnea (OSA). * **Most common organism in AOM:** *Streptococcus pneumoniae*. * **First-line Antibiotic:** High-dose Amoxicillin.

Q: A two-year-old unimmunized child presents with fever for 5 days and a rash behind the ear that appeared the day before presentation. The child also has a running nose and congested eyes. What is the most probable diagnosis?

Measles. **Explanation:** The clinical presentation is classic for **Measles (Rubeola)**. The diagnosis is based on the following high-yield features: 1. **Prodromal Phase:** Fever, rhinorrhea (running nose), and conjunctivitis (congested eyes) are the hallmark "3 Cs" (Cough, Coryza, Conjunctivitis). 2. **Rash Progression:** The rash in measles typically appears on the 4th or 5th day of fever. It is a maculopapular rash that characteristically starts **behind the ears** (at the hairline) and spreads cephalocaudally (downward) to the face, trunk, and extremities. 3. **Immunization Status:** Being "unimmunized" is a significant risk factor, as the first dose of the MR/MMR vaccine is typically given at 9 months. **Why other options are incorrect:** * **Rubella (German Measles):** While the rash also spreads downward, the prodrome is much milder (low-grade fever), and the most characteristic finding is **post-auricular/suboccipital lymphadenopathy**, not severe coryza. * **Mumps:** This primarily presents with painful swelling of the **parotid glands**, not a maculopapular rash. * **Chickenpox (Varicella):** The rash is **pleomorphic** (vesicles, pustules, and scabs present simultaneously) and typically starts on the trunk ("centripetal" distribution), appearing in crops. **NEET-PG High-Yield Pearls:** * **Koplik Spots:** Pathognomonic for measles; seen on the buccal mucosa opposite the lower 2nd molar *before* the rash appears. * **Vitamin A:** Supplementation is mandatory in all children with measles to prevent complications like blindness and pneumonia. * **Infectivity:** Most infectious during the prodromal stage (4 days before to 4 days after the appearance of the rash). * **Subacute Sclerosing Panencephalitis (SSPE):** A rare, delayed neurological complication occurring years after the initial infection.

Q: Pneumonia is a known complication of which of the following diseases?

Measles. **Explanation:** **Pneumonia** is the most common cause of death associated with **Measles (Rubeola)** in children. The measles virus causes significant immunosuppression and disrupts the respiratory epithelium, predisposing the patient to both primary viral pneumonia (Hecht’s giant cell pneumonia) and secondary bacterial pneumonia (commonly caused by *S. pneumoniae*, *H. influenzae*, or *S. aureus*). **Analysis of Options:** * **A. Measles (Correct):** Pneumonia accounts for nearly 60% of measles-related deaths. It can manifest as an interstitial pneumonitis caused by the virus itself or as a secondary bacterial infection following the prodromal phase. * **B. Chickenpox:** While Varicella pneumonia can occur, it is primarily a complication seen in **adults** or immunocompromised individuals, rather than a hallmark complication in the pediatric population compared to measles. * **C. Infectious Mononucleosis:** Caused by EBV, this typically presents with the triad of fever, pharyngitis, and lymphadenopathy. While upper airway obstruction due to tonsillar hypertrophy is a risk, pneumonia is an extremely rare complication. * **D. Mastoiditis:** This is a complication of Acute Otitis Media (AOM), not a primary disease that leads to pneumonia. **Clinical Pearls for NEET-PG:** * **Hecht’s Giant Cell Pneumonia:** A rare, fatal form of measles pneumonia seen in immunocompromised patients, characterized by Warthin-Finkeldey giant cells. * **Vitamin A:** Supplementation is mandatory in measles management as it reduces the severity of complications, including pneumonia and blindness. * **Most Common Complication of Measles:** Otitis Media. * **Most Common Cause of Death in Measles:** Pneumonia (overall) and Encephalitis (in specific age groups).

Question 1

Which of the following statements regarding Chickenpox are correct?

Accepted Answer

May cause pneumonitis

Answer

May be severe in a newborn child infected by the mother in late pregnancy

Answer

Is commonly seen in a congenital form

Answer

Affects the limbs more than the trunk

Question 2

Which of the following is the least common complication of measles?

Accepted Answer

Subacute sclerosing panencephalitis (SSPE)

Answer

Diarrhea

Answer

Pneumonia

Answer

Otitis media

Question 3

Which of the following is false regarding measles?

Accepted Answer

Nikolsky's sign

Answer

Koplik's spots

Answer

Maculopapular skin rash

Answer

Fever and malaise

Question 4

What is true regarding Lymphocytic interstitial pneumonitis (LIP)?

Accepted Answer

May be associated with hepatosplenomegaly

Answer

Is common in vertically acquired HIV infection

Answer

Is due to a protozoal infection

Answer

Is seen on chest X-ray as a perihilar infiltration in a butterfly distribution

Question 5

A 5-year-old child has had eight episodes of acute otitis media in 6 months and has difficulty resolving the effusions between infections. What is the most effective management strategy?

Accepted Answer

Adenoidectomy

Answer

Treating each infection as it arises

Answer

Placement of ventilating tubes

Answer

Prescribing prophylactic antibiotics for 6 months

Question 6

A two-year-old unimmunized child presents with fever for 5 days and a rash behind the ear that appeared the day before presentation. The child also has a running nose and congested eyes. What is the most probable diagnosis?

Accepted Answer

Measles

Answer

Rubella

Answer

Mumps

Answer

Chickenpox

Question 7

A 4-month-old infant presents with cough and a respiratory rate greater than 60/min, without retractions. What is the appropriate management according to the Integrated Management of Childhood Illness (IMNCI) protocol?

Accepted Answer

Administer oral antibiotic, explain danger signs, and arrange for follow-up.

Answer

Administer IM antibiotic and refer urgently.

Answer

Explain danger signs and arrange for follow-up.

Answer

Administer IM antibiotic and hospitalize.

Question 8

Which of the following findings is LEAST suggestive of poliovirus infection?

Accepted Answer

Descending motor paralysis with preservation of tendon reflexes and sensation

Answer

Low grade fever and malaise with complete resolution in 2 to 3 days

Answer

Biphasic illness with several days of fever, then meningeal symptoms and asymmetric flaccid paralysis 5 to 10 days later

Answer

Failure to isolate a virus from the cerebrospinal fluid in the presence of marked meningismus

Question 9

Pneumonia is a known complication of which of the following diseases?

Accepted Answer

Measles

Answer

Chickenpox

Answer

Infectious mononucleosis

Answer

Mastoiditis

Question 10

Which of the following statements is FALSE about diphtheria?

Accepted Answer

Antidiphtheria serum (20,000-100,000 units) is administered in cutaneous diphtheria.

Answer

The most common location for pseudomembrane formation is the fauces.

Answer

Diphtheria is primarily a toxaemia.

Answer

Myocarditis is a common complication of diphtheria.

Infectious Diseases — MCQs

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