Infectious Diseases Practice Questions

Q: Which of the following is NOT true about Herpangina?

More severe than primary herpetic gingivostomatitis. **Explanation:** Herpangina is a common viral infection in children, primarily caused by **Coxsackievirus A**. Understanding its clinical presentation is crucial for differentiating it from other pediatric oral lesions. **1. Why Option C is the correct answer (The False Statement):** Contrary to the option, **Herpangina is generally milder** than Primary Herpetic Gingivostomatitis (PHGS). PHGS, caused by HSV-1, typically presents with high-grade fever, significant malaise, extensive friable/bleeding gums, and widespread oral ulcerations. Herpangina, while uncomfortable, usually involves fewer lesions and a faster recovery period (3–5 days). **2. Analysis of Incorrect Options (True Statements):** * **Option A (Epidemics):** Herpangina frequently occurs in seasonal outbreaks, particularly during summer and autumn months, often spreading in daycare settings. * **Option B (Site Specific):** This is a hallmark diagnostic feature. Lesions in Herpangina are localized to the **posterior oropharynx**, specifically the soft palate, uvula, and tonsillar pillars. In contrast, HSV lesions are usually anterior. * **Option D (Gingivitis is absent):** This is the key clinical differentiator. In Herpangina, the gingiva (gums) are spared. In Primary Herpetic Gingivostomatitis, **gingivitis** (swollen, red, bleeding gums) is a pathognomonic finding. **Clinical Pearls for NEET-PG:** * **Etiology:** Coxsackievirus A (most common); also Coxsackie B and Echoviruses. * **Hand-Foot-Mouth Disease (HFMD):** Caused by Coxsackie A16 or Enterovirus 71; presents like Herpangina but includes a maculopapular/vesicular rash on palms and soles. * **Treatment:** Purely supportive (hydration and analgesics); antibiotics and acyclovir have no role in Herpangina.

Q: Pastia's lines are seen in which condition?

Scarlet fever. **Explanation:** **Scarlet Fever (Option D)** is the correct answer. It is caused by Group A Beta-hemolytic *Streptococcus* (GABHS) which produces **erythrogenic toxins**. **Pastia’s lines** (or Thompson’s lines) are a classic clinical sign characterized by linear petechiae or pink/red lines found in the skin folds, particularly the antecubital fossa, axilla, and groin. These lines occur because the rash is more intense in areas of skin friction and capillary fragility. **Analysis of Incorrect Options:** * **Measles (Option A):** Characterized by **Koplik spots** (enanthem) and a maculopapular rash that starts behind the ears and spreads downwards. It does not feature Pastia’s lines. * **Varicella (Option B):** Presents with a pleomorphic rash (macules, papules, vesicles, and crusts appearing simultaneously) often described as **"dewdrops on a rose petal."** * **Syphilis (Option C):** Secondary syphilis presents with a generalized maculopapular rash involving the **palms and soles**, but not linear petechiae in skin folds. **High-Yield Clinical Pearls for Scarlet Fever:** 1. **Sandpaper Rash:** The rash has a rough, "sunburn-with-goosebumps" texture. 2. **Strawberry Tongue:** Initially "White Strawberry Tongue" (coated), followed by "Red Strawberry Tongue" (denuded papillae). 3. **Circumoral Pallor:** Redness of the face with a distinct pale area around the mouth. 4. **Schultz-Charlton Reaction:** Blanching of the scarlet fever rash when specific antitoxin is injected (historical diagnostic test). 5. **Dick Test:** Used to determine susceptibility to scarlet fever.

Q: Which is the most common complication of this rash?

Secondary skin infections. ***Secondary skin infections*** - **Chickenpox vesicles** are intensely pruritic, leading to **scratching** and subsequent **bacterial superinfection** with organisms like *Staphylococcus aureus* or *Streptococcus pyogenes*. - This is the **most frequent complication** of varicella, occurring in up to 5-10% of cases, especially in children. *Otitis media* - While **otitis media** can occur as a complication of varicella, it is **less common** than secondary bacterial skin infections. - More frequently associated with **respiratory viral infections** rather than the characteristic vesicular rash of chickenpox. *Bronchopneumonia* - **Varicella pneumonia** is a serious but **rare complication**, occurring in less than 1% of cases, primarily in adults and immunocompromised patients. - **Secondary skin infections** remain far more common than respiratory complications in typical pediatric varicella cases. *Reye syndrome* - **Reye syndrome** is a rare but serious complication associated with **aspirin use** during varicella or influenza infections. - This complication has become **extremely uncommon** due to widespread avoidance of aspirin in children with viral illnesses.

Q: Which of the following is NOT a complication of chickenpox?

Enteritis. **Explanation:** Chickenpox, caused by the **Varicella-Zoster Virus (VZV)**, is a highly contagious viral infection. While it is typically self-limiting in healthy children, it can lead to various systemic complications. **Why Enteritis is the Correct Answer:** Enteritis (inflammation of the small intestine) is **not** a recognized complication of chickenpox. VZV primarily targets the skin, respiratory system, and central nervous system. Gastrointestinal involvement is extremely rare and not part of the classic clinical spectrum of the disease. **Analysis of Incorrect Options:** * **Pneumonia:** This is the **most serious complication in adults** and immunocompromised individuals. It typically presents with cough and dyspnea 3–5 days after the rash appears. * **Meningitis/Encephalitis:** Neurological complications are well-documented. **Acute Cerebellar Ataxia** (presenting with nystagmus and unsteady gait) is the most common CNS complication in children, while encephalitis and aseptic meningitis can also occur. * **Reye’s Syndrome:** This is a rare but fatal condition involving acute encephalopathy and fatty liver degeneration. It is strongly associated with the use of **aspirin (salicylates)** during a viral prodrome like chickenpox or influenza. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication in children:** Secondary bacterial infection of skin lesions (usually *Staph. aureus* or *Group A Strep*). * **Congenital Varicella Syndrome:** Occurs if the mother is infected in the first 20 weeks of pregnancy; characterized by cicatricial skin scarring, limb hypoplasia, and microcephaly. * **Treatment of choice:** Oral Acyclovir (if started within 24 hours of rash) for high-risk cases; supportive care for healthy children. * **Prevention:** Live attenuated vaccine (Oka strain).

Q: Parotitis and orchitis are common manifestations of which disease?

Mumps. **Explanation:** **Mumps** is an acute viral infection caused by the **Rubulavirus** (Paramyxoviridae family). It is characterized by a predilection for glandular and nervous tissues. 1. **Why Mumps is correct:** * **Parotitis:** The most common clinical manifestation (95% of symptomatic cases), typically presenting as painful, usually bilateral swelling of the parotid glands. * **Orchitis:** The most common complication in post-pubertal males (occurring in up to 30-40% of cases). It is usually unilateral and can lead to testicular atrophy, though permanent infertility is rare. 2. **Why other options are incorrect:** * **Diphtheria:** Caused by *Corynebacterium diphtheriae*, it presents with a "bull-neck" appearance due to cervical lymphadenopathy and a greyish pseudomembrane in the pharynx. It does not cause parotitis or orchitis. * **Measles (Rubeola):** Characterized by the 3 C’s (Cough, Coryza, Conjunctivitis), Koplik spots, and a maculopapular rash. Common complications include pneumonia and SSPE. * **Rubella (German Measles):** Presents with a milder rash and significant **post-auricular and suboccipital lymphadenopathy**, not parotid swelling. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication in children:** Aseptic meningitis. * **Most common cause of acquired sensorineural deafness** in children is Mumps (usually unilateral). * **Pancreatitis** is another classic glandular manifestation of Mumps. * **Diagnosis:** Clinical diagnosis is standard; elevated **Serum Amylase** is a key laboratory finding due to parotid involvement. * **Prevention:** Live attenuated vaccine (Jeryl Lynn strain) as part of the MMR vaccine.

Q: Paralysis in polio is characterized by?

Lower motor neurone type. **Explanation:** Poliomyelitis is caused by an enterovirus that specifically targets and destroys the **anterior horn cells** of the spinal cord. These cells are the primary cell bodies of the **Lower Motor Neurons (LMN)**. **1. Why "Lower motor neurone type" is correct:** Since the pathology involves the destruction of the anterior horn cells, the resulting paralysis follows a classic LMN pattern. This is characterized by **Acute Flaccid Paralysis (AFP)**, which includes loss of muscle tone (atonia), loss of reflexes (areflexia), and muscle wasting/atrophy. **2. Why the other options are incorrect:** * **Exaggerated tendon reflexes:** This is a feature of Upper Motor Neuron (UMN) lesions. In Polio, reflexes are typically diminished or absent (hyporeflexia/areflexia). * **Symmetrical paralysis:** Polio is characteristically **asymmetrical**. It often affects one limb more than the other (most commonly the legs) and follows a "random" distribution based on which specific neuronal clusters are destroyed. * **Tonic paralysis:** Polio causes **flaccid** paralysis. Tonic (spastic) paralysis is seen in UMN lesions or conditions like Tetanus. **High-Yield Clinical Pearls for NEET-PG:** * **Hallmark of Polio:** Asymmetrical, descending, flaccid paralysis with intact sensory perception (Sensory loss is NEVER seen in Polio). * **Tripod Sign:** A clinical sign where the child sits with hands placed behind for support due to spinal muscle weakness. * **Post-Polio Syndrome:** Occurs decades after the initial infection due to the gradual failure of over-exerted surviving motor neurons. * **Surveillance:** Under the Global Polio Eradication Initiative, any case of AFP in a child <15 years must be investigated (requires two stool samples 24 hours apart within 14 days of onset).

Q: A 3-year-old child presents with symptoms of influenza. Aspirin is contraindicated in this patient due to the increased risk of which of the following conditions?

Reye's syndrome. ### Explanation **Correct Answer: D. Reye's syndrome** **Mechanism and Rationale:** Reye’s syndrome is a rare but life-threatening condition characterized by **acute encephalopathy** and **fatty degeneration of the liver**. It is strongly associated with the use of **salicylates (Aspirin)** in children and adolescents during viral prodromes, most commonly **Influenza (Type B)** and **Varicella (Chickenpox)**. The underlying pathophysiology involves **mitochondrial dysfunction**, leading to impaired fatty acid oxidation. This results in hyperammonemia and cerebral edema. Clinically, it presents with protracted vomiting followed by altered mental status, seizures, and hepatomegaly without jaundice. **Analysis of Incorrect Options:** * **A. Gastric bleeding:** While aspirin causes gastric irritation and bleeding in adults due to COX-1 inhibition, it is not the primary reason for its absolute contraindication in pediatric viral infections. * **B. Thrombocytopenia:** Aspirin causes irreversible inhibition of platelet aggregation (anti-platelet effect), but it does not typically cause a decrease in the absolute platelet count (thrombocytopenia). * **C. Fanconi syndrome:** This is a disorder of proximal renal tubular function. While certain drugs (like expired tetracycline or cisplatin) can cause it, aspirin is not a recognized trigger. **High-Yield Clinical Pearls for NEET-PG:** * **Biochemical Hallmarks:** Elevated serum ammonia, prolonged Prothrombin Time (PT/INR), and elevated AST/ALT with **normal bilirubin**. * **Liver Biopsy Findings:** Microvesicular steatosis (small fat droplets in hepatocytes). * **Exceptions:** Aspirin is still used in children for specific conditions like **Kawasaki Disease** and **Juvenile Idiopathic Arthritis (JIA)**, under strict supervision. * **Drug of Choice:** Acetaminophen (Paracetamol) or Ibuprofen are the preferred antipyretics in children with viral fever.

Question 1

A 9-year-old girl child developed a 10 mm area of induration on the left forearm 72 hours after intradermal injection of 0.1 ml of purified protein derivative (PPD). Which of the following is most likely to be seen on the X-ray of this patient?

Accepted Answer

No abnormal findings

Answer

Marked hilar adenopathy

Answer

Upper lobe calcifications

Answer

Reticulo-nodular densities

Question 2

A 5-year-old unimmunized child presented with high fever, sore throat, dysphagia, and voice change. A throat swab from a whitish lesion was taken for diagnosis. What is the most likely diagnosis?

Accepted Answer

Diphtheria

Answer

Mumps

Answer

Pertussis

Answer

Streptococcal pharyngitis

Question 3

Which of the following is NOT true about Herpangina?

Accepted Answer

More severe than primary herpetic gingivostomatitis

Answer

Occurs in epidemics

Answer

Site specific (Occurs on palate and uvula)

Answer

Gingivitis is absent

Question 4

Pastia's lines are seen in which condition?

Accepted Answer

Scarlet fever

Answer

Measles

Answer

Varicella

Answer

Syphilis

Question 5

Which is the most common complication of this rash?

Accepted Answer

Secondary skin infections

Answer

Otitis media

Answer

Bronchopneumonia

Answer

Reye syndrome

Question 6

Which of the following is NOT a complication of chickenpox?

Accepted Answer

Enteritis

Answer

Meningitis

Answer

Pneumonia

Answer

Reye's Syndrome

Question 7

Parotitis and orchitis are common manifestations of which disease?

Accepted Answer

Mumps

Answer

Diphtheria

Answer

Measles

Answer

Rubella

Question 8

Paralysis in polio is characterized by?

Accepted Answer

Lower motor neurone type

Answer

Exaggerated tendon reflexes

Answer

Symmetrical paralysis

Answer

Tonic paralysis

Question 9

Which of the following is NOT a contraindication to DPT vaccination?

Accepted Answer

Local reaction to a previous DPT dose

Answer

High fever following a previous DPT dose

Answer

Infantile spasms

Answer

Seizures after a previous DPT dose

Question 10

A 3-year-old child presents with symptoms of influenza. Aspirin is contraindicated in this patient due to the increased risk of which of the following conditions?

Accepted Answer

Reye's syndrome

Answer

Gastric bleeding

Answer

Thrombocytopenia

Answer

Fanconi syndrome

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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