Infectious Diseases Practice Questions

Q: Papulovesicular oral lesions are seen in which condition?

Herpangina. **Explanation:** The correct answer is **Herpangina**. This condition is primarily caused by **Coxsackievirus A** (and occasionally Coxsackievirus B or Echoviruses). It is characterized by the sudden onset of fever, sore throat, and the pathognomonic finding of small **papulovesicular lesions** (1–2 mm) that rapidly ulcerate. These lesions are specifically localized to the **posterior oropharynx**, including the anterior tonsillar pillars, soft palate, and uvula. **Analysis of Options:** * **Measles (Rubeola):** Characterized by **Koplik spots**, which are bluish-white specks on an erythematous base found on the buccal mucosa opposite the lower molars. They are macules, not vesicles. * **Rubella (German Measles):** Associated with **Forchheimer spots**, which are small, red petechiae on the soft palate. These are vascular changes, not vesicular lesions. * **Hand, Foot, and Mouth Disease (HFMD):** While also caused by Coxsackievirus A16 and featuring oral vesicles, the question asks for the condition defined by these lesions. In HFMD, vesicles are typically found on the **buccal mucosa and tongue** (anterior oral cavity), accompanied by a characteristic rash on the palms and soles. **High-Yield Clinical Pearls for NEET-PG:** * **Herpangina vs. HFMD:** Herpangina involves the **posterior** pharynx; HFMD involves the **anterior** mouth plus extremities. * **Etiology:** Both are Enteroviruses, most commonly **Coxsackievirus A**. * **Differential Diagnosis:** Unlike Herpetic Gingivostomatitis (HSV-1), Herpangina does **not** involve the gums (gingiva) and lacks the diffuse swelling seen in primary herpes. * **Seasonality:** These infections typically peak in summer and autumn months.

Q: A rash with retro-auricular origin is typically seen in which of the following conditions?

Rubeola. **Explanation:** The correct answer is **Rubeola (Measles)**. In Rubeola, the characteristic maculopapular rash typically appears on the 4th day of fever. It follows a classic **cephalocaudal progression**, starting behind the ears (**retro-auricular**) and along the hairline, then spreading downwards to the face, neck, trunk, and finally the extremities. This specific anatomical starting point is a hallmark clinical feature used to differentiate it from other exanthematous illnesses. **Analysis of Options:** * **Rubella (German Measles):** While the rash also starts on the face and spreads downwards, it is typically lighter (pinkish), non-confluent, and disappears much faster ("3-day measles"). The most characteristic feature of Rubella is **post-auricular and suboccipital lymphadenopathy**, rather than just the rash origin. * **Chickenpox (Varicella):** The rash typically starts on the **trunk** (centripetal distribution) and is pleomorphic (macules, papules, vesicles, and crusts present simultaneously). * **Mumps:** This is a viral infection primarily affecting the parotid glands. It presents with **parotid swelling** and does not typically present with a generalized maculopapular rash. **High-Yield Clinical Pearls for NEET-PG:** * **Koplik Spots:** Pathognomonic for Measles; seen on the buccal mucosa opposite the lower 2nd molars *before* the rash appears. * **Vitamin A:** Supplementation is mandatory in Measles management to reduce morbidity and mortality. * **Complications:** The most common complication is Otitis Media; the most common cause of death is Pneumonia; the most dreaded late complication is SSPE (Subacute Sclerosing Panencephalitis). * **Infectivity:** Measles is most infectious during the prodromal (catarrhal) stage.

Q: Which of the following is FALSE regarding Poliomyelitis?

Bilateral and symmetrical involvement. **Explanation:** Poliomyelitis is an acute viral infection caused by the Poliovirus (an enterovirus), primarily affecting the anterior horn cells of the spinal cord. **Why Option B is the Correct (False) Statement:** The hallmark of paralytic poliomyelitis is **asymmetrical** and **random** involvement of muscles. It typically affects one limb more than the other (most commonly the legs) and rarely presents with perfect symmetry. If a patient presents with acute flaccid paralysis that is bilateral and symmetrical, clinicians should prioritize a diagnosis of Guillain-Barré Syndrome (GBS) over Polio. **Analysis of Other Options:** * **Option A (Descending paralysis):** While Polio is often described as affecting proximal muscles more than distal ones, the paralysis characteristically spreads in a **descending** fashion (starting from the hip/shoulder and moving downwards). * **Option C (Non-progressive condition):** Once the febrile illness subsides and the paralysis is established (usually within 48–72 hours), the paralysis is **static and non-progressive**. Any further "progression" after the fever touches baseline is unlikely to be Polio. * **Option D (LMN type paralysis):** Because the virus destroys the **anterior horn cells** (the final common pathway of the motor system), it results in classic **Lower Motor Neuron (LMN)** signs: flaccidity, loss of deep tendon reflexes, and eventual muscle atrophy. **High-Yield Clinical Pearls for NEET-PG:** * **Most common presentation:** Asymptomatic/Inapparent infection (>90-95%). * **CSF Findings:** Albuminocytologic dissociation is **absent** (unlike GBS). There is initial pleocytosis. * **Diagnosis:** Isolation of the virus from **stool samples** (two samples collected 24 hours apart) is the gold standard for AFP surveillance. * **Prognosis:** Maximum recovery occurs within the first 6 months; paralysis persisting beyond 60 days is usually permanent.

Q: Forschheimer spots are seen on which of the following locations?

Uvula. **Explanation:** **Forschheimer spots** are a classic clinical sign associated with **Rubella (German Measles)**. They are characterized by small, pinpoint, reddish-pink spots (petechiae) located on the **soft palate and uvula**. These spots appear during the prodromal phase or on the first day of the rash in approximately 20% of Rubella patients. While characteristic, they are not pathognomonic as they can occasionally be seen in Scarlet fever or Infectious Mononucleosis. **Analysis of Options:** * **A. Uvula (Correct):** This is the anatomical site for Forschheimer spots, specifically involving the soft palate and the uvula. * **B. Trunk:** While the Rubella rash (exanthem) typically starts on the face and spreads to the trunk, Forschheimer spots are an *enanthem* (mucosal rash) and are not found on the skin of the trunk. * **C. Dorsal aspect of hand:** This is not a site for specific enanthems. However, Gottron papules (seen in Dermatomyositis) are typically found on the dorsal aspect of interphalangeal joints. * **D. Penis:** This is not a site for Forschheimer spots. Genital lesions are more characteristic of STIs like Syphilis (Chancre) or HSV. **Clinical Pearls for NEET-PG:** * **Koplik Spots vs. Forschheimer Spots:** Koplik spots (Measles) are bluish-white spots on an erythematous base located on the buccal mucosa opposite the lower molars. Forschheimer spots (Rubella) are reddish petechiae on the soft palate/uvula. * **Rubella Triad (Congenital):** Cataract, Sensorineural hearing loss, and PDA (Patent Ductus Arteriosus). * **Rash Progression:** Rubella rash is known for its rapid spread and disappearance within 3 days ("3-day measles").

Q: Which of the following complications has been associated with the adverse effects of rotavirus vaccine?

Intussusception. **Explanation:** The correct answer is **D. Intussusception.** **Why Intussusception is the correct answer:** Rotavirus vaccines (such as Rotarix and RotaTeq) are live-attenuated oral vaccines. Historically, the first-generation vaccine (Rotashield) was withdrawn in 1999 due to a significant association with **intussusception** (telescoping of one segment of the intestine into another). While current vaccines have a much lower risk profile, a small but statistically significant risk (approximately 1 to 5 cases per 100,000 vaccinated infants) remains. The risk is highest within the first **7 days** following the first dose. Consequently, the vaccine is contraindicated in infants with a prior history of intussusception or uncorrected congenital malformations of the GI tract (like Meckel’s diverticulum). **Why other options are incorrect:** * **A. Guillain-Barré syndrome:** This is primarily associated with the **Influenza vaccine** and *Campylobacter jejuni* infections, not rotavirus. * **B. Hemolytic anemia:** This is not a recognized side effect of the rotavirus vaccine. It is more commonly associated with drugs (e.g., dapsone in G6PD deficiency) or infections. * **C. Febrile seizures:** While common after DPT or MMR vaccines, they are not a characteristic adverse effect of the oral rotavirus vaccine. **High-Yield Clinical Pearls for NEET-PG:** * **Age Limits:** To minimize the risk of intussusception, the WHO/IAP recommends the first dose be given after 6 weeks and the series completed by **8 months** of age. * **Vaccine Types:** Rotarix (Monovalent, 2 doses) and RotaTeq/Rotavac (Pentavalent, 3 doses). * **Contraindications:** History of intussusception, SCID (Severe Combined Immunodeficiency), and acute gastroenteritis.

Q: An 8-year-old child presents with a 3-day history of high-grade fever, vomiting, headache, and decreased responsiveness. Examination reveals a distressed child in shock, with maculopapular and ecchymotic rashes, bleeding from venipuncture sites, and hepatomegaly. Investigations show PCV = 65%, WBC = 4000, platelets = 25,000, and mildly prolonged PT. Chest X-ray reveals a left-sided pleural effusion. What is the most likely diagnosis?

Dengue hemorrhagic fever. The correct answer is **Dengue Hemorrhagic Fever (DHF)**. ### **Why it is correct:** The clinical presentation and laboratory findings perfectly match the **WHO criteria for DHF**: 1. **High-grade fever** and constitutional symptoms. 2. **Hemorrhagic manifestations:** Ecchymotic rashes and bleeding from venipuncture sites. 3. **Thrombocytopenia:** Platelet count 20% from baseline) and the presence of **pleural effusion** and **hepatomegaly** confirm plasma leakage into the third space. ### **Why other options are incorrect:** * **Meningococcemia with DIC:** While it causes shock and purpura, it does not typically cause significant hemoconcentration (high PCV) or pleural effusion. WBC count is usually high (leukocytosis), whereas Dengue typically shows leukopenia. * **Leptospirosis:** Presents with conjunctival suffusion, jaundice, and renal failure. While it can cause bleeding (Weil’s disease), it does not explain the massive plasma leakage seen here. * **Complicated Malaria:** Can cause shock (Algid malaria) and thrombocytopenia, but the hallmark is severe anemia (low PCV), not hemoconcentration (high PCV). ### **NEET-PG High-Yield Pearls:** * **Dengue Grading:** DHF is graded I to IV. Grades III and IV (presence of shock) are termed **Dengue Shock Syndrome (DSS)**. * **Critical Phase:** Occurs during defervescence (day 3–7). This is when plasma leakage and shock are most likely to occur. * **Fluid Management:** Isotonic crystalloids (Ringer’s Lactate) are the gold standard for resuscitation. * **Diagnosis:** NS1 antigen (Day 1–5); IgM/IgG ELISA (after Day 5).

Q: In a 7-month-old child diagnosed with Haemophilus influenzae meningitis, which of the following investigations should be done on follow-up?

Brainstem Evoked Response Audiometry (BERA). **Explanation:** **1. Why BERA is the Correct Answer:** Sensorineural hearing loss (SNHL) is the most common long-term complication of bacterial meningitis in children. *Haemophilus influenzae* type b (Hib) is particularly notorious for causing inflammatory damage to the cochlea (labyrinthitis ossificans). Since a 7-month-old infant cannot undergo conventional subjective audiometry, **Brainstem Evoked Response Audiometry (BERA)** is the gold standard objective investigation to assess hearing integrity. It should ideally be performed at the time of discharge or within 4 weeks of recovery to ensure early intervention and prevent speech delays. **2. Why Other Options are Incorrect:** * **CECT Scan (Option B):** CECT is not a routine follow-up investigation. It is indicated only if there is clinical suspicion of acute complications like subdural effusion, empyema, or brain abscess during the active phase of the disease. * **MRI (Option C):** While MRI is superior for visualizing soft tissue and inflammatory changes, it is not a routine screening tool for all meningitis survivors. It is reserved for specific neurological deficits or refractory cases. * **X-ray Skull (Option D):** This has no role in the management or follow-up of meningitis as it cannot visualize the brain parenchyma, meninges, or auditory pathways. **3. NEET-PG High-Yield Pearls:** * **Most common complication of bacterial meningitis:** Hearing loss (SNHL). * **Most common cause of meningitis in infants (post-neonatal):** *Streptococcus pneumoniae* (now more common than Hib due to vaccination). * **Steroid Role:** Dexamethasone (given 20 mins before or with the first dose of antibiotics) is specifically proven to reduce the incidence of hearing loss in *H. influenzae* meningitis. * **Follow-up Rule:** Every child post-meningitis must undergo a hearing assessment before discharge.

Q: A patient presents with fever, cough, and headache. On the fourth day of illness, a rash develops. What is the probable diagnosis?

Measles. **Explanation:** The clinical presentation of fever, cough, and headache followed by the appearance of a rash on the **fourth day** is a classic hallmark of **Measles (Rubeola)**. In Measles, the illness follows a predictable timeline: a 3-day prodromal phase characterized by the "3 Cs" (Cough, Coryza, and Conjunctivitis) and high-grade fever. The maculopapular rash typically appears on the **4th day**, starting behind the ears and spreading cephalocaudally (head to toe). **Why other options are incorrect:** * **Mumps:** Primarily presents with painful parotid swelling (parotitis). While fever and headache occur, a generalized maculopapular rash is not a standard clinical feature. * **Smallpox:** The rash typically appears on the **3rd day** of illness. Unlike measles, the rash is centrifugal (more dense on extremities) and progresses synchronously from papules to umbilicated vesicles and pustules. * **Chickenpox (Varicella):** The rash appears very early, usually on the **1st day** of fever. It is pleomorphic (all stages of rash—vesicles, papules, crusts—seen simultaneously) and has a centripetal distribution (more on the trunk). **High-Yield Clinical Pearls for NEET-PG:** * **Koplik Spots:** Pathognomonic for measles; small white spots on an erythematous base found on the buccal mucosa opposite the lower 2nd molars (appears 1–2 days before the rash). * **Vitamin A:** Supplementation is mandatory in measles management to reduce morbidity and mortality (especially blindness and pneumonia). * **Infectivity:** Patients are infectious from 4 days before to 4 days after the appearance of the rash. * **SSPE:** Subacute Sclerosing Panencephalitis is a rare, delayed neurological complication occurring years after the initial infection.

Q: What is the time gap between the appearance of Koplik's spots and the cutaneous rash in measles?

3-4 days. **Explanation:** Measles (Rubeola) follows a distinct chronological progression of clinical features. The correct answer is **3-4 days** because of the specific timing of the prodromal and eruptive phases. 1. **Why Option B is correct:** Measles has a prodromal stage characterized by the "3 Cs" (Cough, Coryza, Conjunctivitis) and fever. **Koplik’s spots**—the pathognomonic enanthem—typically appear on the buccal mucosa opposite the lower second molars about **2 days before** the rash. The characteristic maculopapular rash (exanthem) usually appears on the **4th day** of the fever. Therefore, the interval between the appearance of Koplik’s spots and the cutaneous rash is approximately **2 to 4 days** (averaging 3-4 days). 2. **Why other options are incorrect:** * **Option A (24 hours):** This is too short; Koplik's spots usually precede the rash by at least 48 hours. * **Option C (2 weeks):** This is the approximate incubation period of Measles (10–14 days), not the interval between clinical signs. * **Option D (10 days):** This is the time from exposure to the onset of the first symptom (fever), not the gap between the spots and the rash. **High-Yield Clinical Pearls for NEET-PG:** * **Koplik’s Spots:** Described as "grains of salt on a red background." They disappear within 24–48 hours after the rash appears. * **Rash Progression:** Starts behind the ears (retro-auricular), spreads to the face/neck, then downwards to the trunk and limbs (cephalocaudal progression). * **Infectivity:** A patient is infectious from **4 days before to 4 days after** the appearance of the rash. * **Vitamin A:** Supplementation is recommended for all children with measles to prevent complications like blindness and pneumonia.

Q: Which among the following is the commonest complication of meningitis?

Seizure. **Explanation:** Acute bacterial meningitis is a medical emergency in pediatrics, and understanding its complications is high-yield for NEET-PG. **Why Seizure is the Correct Answer:** Seizures are the **most common acute complication** of meningitis, occurring in approximately **20–30%** of patients. They typically occur within the first 48–72 hours of illness. The underlying pathophysiology involves cortical irritation caused by meningeal inflammation, cerebral edema, focal ischemia (due to vasculitis), or metabolic derangements (like hyponatremia due to SIADH). **Analysis of Incorrect Options:** * **Deafness (Sensorineural Hearing Loss):** This is the **most common permanent/long-term neurological sequela** (occurring in ~10% of survivors), particularly with *S. pneumoniae*. However, it is less frequent than acute seizures. * **Brain Abscess:** This is a rare complication of meningitis. It is more commonly associated with specific organisms like *Citrobacter koseri* or *Proteus* in neonates. * **Hydrocephalus:** This is a known complication (usually communicating type due to impaired CSF absorption), but its incidence is lower than that of seizures. **NEET-PG High-Yield Pearls:** * **Most common sequela overall:** Seizures (Acute phase). * **Most common permanent sequela:** Hearing loss (Perform BERA/Audiometry for all survivors before discharge). * **Most common cause of meningitis (overall):** *Streptococcus pneumoniae*. * **Most common cause in neonates:** Group B Streptococcus (GBS), followed by *E. coli*. * **Subdural effusion:** Common in infants (especially with *H. influenzae*); suspect if there is persistent fever or bulging fontanelle despite 48-72 hours of antibiotics.

Question 1

Papulovesicular oral lesions are seen in which condition?

Accepted Answer

Herpangina

Answer

Measles

Answer

Rubella

Answer

Hand foot and mouth disease

Question 2

A rash with retro-auricular origin is typically seen in which of the following conditions?

Accepted Answer

Rubeola

Answer

Rubella

Answer

Chickenpox

Answer

Mumps

Question 3

Which of the following is FALSE regarding Poliomyelitis?

Accepted Answer

Bilateral and symmetrical involvement

Answer

Descending paralysis

Answer

Non-progressive condition

Answer

Lower Motor Neuron (LMN) type paralysis

Question 4

Forschheimer spots are seen on which of the following locations?

Accepted Answer

Uvula

Answer

Trunk

Answer

Dorsal aspect of hand

Answer

Penis

Question 5

Which of the following complications has been associated with the adverse effects of rotavirus vaccine?

Accepted Answer

Intussusception

Answer

Guillain-Barré syndrome

Answer

Hemolytic anemia

Answer

Febrile seizures

Question 6

An 8-year-old child presents with a 3-day history of high-grade fever, vomiting, headache, and decreased responsiveness. Examination reveals a distressed child in shock, with maculopapular and ecchymotic rashes, bleeding from venipuncture sites, and hepatomegaly. Investigations show PCV = 65%, WBC = 4000, platelets = 25,000, and mildly prolonged PT. Chest X-ray reveals a left-sided pleural effusion. What is the most likely diagnosis?

Accepted Answer

Dengue hemorrhagic fever

Answer

Meningococcemia with DIC

Answer

Leptospirosis

Answer

Complicated malaria

Question 7

In a 7-month-old child diagnosed with Haemophilus influenzae meningitis, which of the following investigations should be done on follow-up?

Accepted Answer

Brainstem Evoked Response Audiometry (BERA)

Answer

Contrast-Enhanced Computed Tomography (CECT) Scan

Answer

Magnetic Resonance Imaging (MRI)

Answer

X-ray Skull

Question 8

A patient presents with fever, cough, and headache. On the fourth day of illness, a rash develops. What is the probable diagnosis?

Accepted Answer

Measles

Answer

Mumps

Answer

Smallpox

Answer

Chickenpox

Question 9

What is the time gap between the appearance of Koplik's spots and the cutaneous rash in measles?

Accepted Answer

3-4 days

Answer

24 hours

Answer

2 weeks

Answer

10 days

Question 10

Which among the following is the commonest complication of meningitis?

Accepted Answer

Seizure

Answer

Deafness

Answer

Brain abscess

Answer

Hydrocephalus

Infectious Diseases — MCQs

Infectious Diseases — MCQs

On this page

Practice by Chapter

Want unlimited practice?