RNA Viruses: Paramyxoviruses — MCQs
Uveo-parotitis is seen in
A child presented with bluish-white spots in the mouth followed by a rash. What is the genome of the most likely causative agent?
What is the primary function of the nucleocapsid proteins in the measles virus?
A month old HIV positive child following an upper respiratory infection developed sudden onset of breathlessness. The chest x-ray shows hyperinflation. The O2 saturation was greater than 90%. What is the most appropriate antiviral therapy among the given options?
A 4-year-old boy presents with low-grade fever, inspiratory stridor, and barking cough for the past 5 days. Examination reveals a hoarse voice, a moderately inflamed pharynx, and a slightly increased respiratory rate. His chest x-ray showed subglottic narrowing appearing like a steeple. Which among the following is not indicated in the treatment of this condition?
Koplik spots are pathognomonic of which of the following?
A 4-year-old child with barking cough is diagnosed with croup. Which virus is most likely responsible?
All of the following are RNA viruses except
Which of the following statements about paramyxoviruses is false?
Which of the following is an RNA oncogenic virus?
RNA Viruses: Paramyxoviruses Indian Medical PG Practice Questions and MCQs
Question 1: Uveo-parotitis is seen in
- A. Mumps
- B. Sarcoidosis (Correct Answer)
- C. Measles
- D. Cystic fibrosis
Explanation: ***Sarcoidosis*** - **Uveo-parotitis** (also known as Heerfordt's syndrome or uveoparotid fever) is a rare manifestation of **sarcoidosis**, characterized by swelling of the **parotid glands**, anterior **uveitis**, fever, and sometimes facial nerve palsy [1]. - Sarcoidosis is a chronic inflammatory disease that can affect multiple organs, with **granuloma formation** being its pathological hallmark [1]. *Mumps* - Mumps primarily causes **parotitis**, an inflammation of the parotid glands, but it is typically not associated with **uveitis**. - It is a viral infection characterized by sudden onset of fever, headache, malaise, myalgia, and swelling of one or both parotid glands. *Measles* - Measles is a viral infection that causes a **generalized maculopapular rash**, fever, cough, coryza, and conjunctivitis, but it does not cause **uveo-parotitis**. - Ocular involvement in measles is usually limited to **conjunctivitis** rather than deeper inflammatory conditions like uveitis. *Cystic fibrosis* - **Cystic fibrosis** is a genetic disorder affecting exocrine glands, leading to thick mucus production in the lungs, pancreas, and other organs. - While it can lead to various systemic complications, it is not associated with **uveo-parotitis**.
Question 2: A child presented with bluish-white spots in the mouth followed by a rash. What is the genome of the most likely causative agent?
- A. Enveloped virus with single-stranded RNA (Correct Answer)
- B. Double stranded Naked RNA
- C. Naked virus with single-stranded RNA
- D. Double stranded Enveloped RNA
Explanation: ***Enveloped virus with single-stranded RNA*** - Bluish-white spots in the mouth (**Koplik spots**) followed by a rash are pathognomonic for **measles**, which is caused by the **measles virus**. - The measles virus is a **paramyxovirus**, characterized as an **enveloped, negative-sense, single-stranded RNA virus**. *Double stranded Naked RNA* - No major human pathogen belongs to this specific genomic and structural classification. - Most **dsRNA viruses** like **rotavirus** are **naked** but cause gastroenteritis, not measles. *Naked virus with single-stranded RNA* - Viruses like **rhinovirus** (common cold) or **poliovirus** fit this description but do not cause Koplik spots or measles. - **Naked viruses** lack a lipid envelope, making them generally more resistant to environmental factors. *Double stranded Enveloped RNA* - There are no known medically significant human viruses that are both **enveloped** and contain **double-stranded RNA**. - Viral genomes are typically either DNA or RNA, and RNA viruses are usually single-stranded (positive or negative sense) or double-stranded, with or without an envelope.
Question 3: What is the primary function of the nucleocapsid proteins in the measles virus?
- A. Protect the RNA from degradation during replication. (Correct Answer)
- B. Facilitate the assembly of the virion structure.
- C. Assist in the packaging of the viral genome.
- D. Protect the genome RNA from nuclease digestion and recognize the location in the cell membrane for budding.
Explanation: **Protect the RNA from degradation during replication.** - The **nucleocapsid proteins** (N proteins) in the measles virus encapsidate the **viral RNA genome**, forming a helical ribonucleoprotein (RNP) complex. - This **encapsidation** provides crucial protection to the RNA from cellular **nucleases**, preventing its degradation and maintaining its integrity for successful replication and transcription. *Facilitate the assembly of the virion structure.* - While nucleocapsid proteins are part of the virion structure, their primary function isn't to **facilitate the assembly** but rather to protect the genetic material within that structure. - **Matrix proteins** and other viral components are more directly involved in the overall assembly and budding process. *Assist in the packaging of the viral genome.* - **Packaging** of the viral genome is a separate, although related, process where the protected nucleocapsid is incorporated into the newly forming virion. - The fundamental role of the nucleocapsid protein is the **protection and organization of the RNA**, which then enables efficient packaging. *Protect the genome RNA from nuclease digestion and recognize the location in the cell membrane for budding.* - **Protecting the genome RNA from nuclease digestion** is indeed a key function of nucleocapsid proteins. - However, **recognizing the location in the cell membrane for budding** is primarily mediated by the viral **matrix (M) protein**, which links the nucleocapsid to the envelope glycoproteins.
Question 4: A month old HIV positive child following an upper respiratory infection developed sudden onset of breathlessness. The chest x-ray shows hyperinflation. The O2 saturation was greater than 90%. What is the most appropriate antiviral therapy among the given options?
- A. IV Ganciclovir
- B. Ribavirin (Correct Answer)
- C. Cotrimoxazole
- D. Nebulized Acyclovir
Explanation: **Ribavirin** - The clinical presentation of a 1-month-old HIV-positive infant with sudden breathlessness, hyperinflation on chest X-ray, and oxygen saturation >90%, following an URI, is highly suggestive of **Respiratory Syncytial Virus (RSV) bronchiolitis**. - **Ribavirin** is an antiviral drug that was historically used for severe RSV infection, especially in high-risk infants like those who are immunocompromised. - **Note:** Current guidelines emphasize supportive care as primary treatment; ribavirin use is now controversial due to limited efficacy and toxicity concerns. *IV Ganciclovir* - **Ganciclovir** is primarily used for the treatment of **Cytomegalovirus (CMV)** infections, which typically present differently than the acute bronchiolitis described. - CMV pneumonitis often manifests with diffuse interstitial infiltrates and may be accompanied by other systemic CMV manifestations. *Cotrimoxazole* - **Cotrimoxazole (trimethoprim-sulfamethoxazole)** is the drug of choice for prophylaxis and treatment of **Pneumocystis jirovecii pneumonia (PJP)**. - While PJP is common in HIV-positive infants, the acute onset, hyperinflation, and O2 saturation >90% are less typical for severe PJP, and cotrimoxazole is an antibiotic, not an antiviral. *Nebulized Acyclovir* - **Acyclovir** is an antiviral agent used to treat **herpes simplex virus (HSV)** and **varicella-zoster virus (VZV)** infections. - Respiratory involvement with HSV or VZV in an infant would present with different clinical features and radiological findings than those described.
Question 5: A 4-year-old boy presents with low-grade fever, inspiratory stridor, and barking cough for the past 5 days. Examination reveals a hoarse voice, a moderately inflamed pharynx, and a slightly increased respiratory rate. His chest x-ray showed subglottic narrowing appearing like a steeple. Which among the following is not indicated in the treatment of this condition?
- A. Nebulized racemic epinephrine
- B. Intramuscular dexamethasone
- C. Helium oxygen mixture
- D. Parenteral cefotaxime (Correct Answer)
- E. Nebulized budesonide
Explanation: ***Parenteral cefotaxime*** - The clinical presentation (low-grade fever, inspiratory stridor, barking cough, hoarse voice) and the **steeple sign** on chest X-ray are classic for **croup (laryngotracheobronchitis)**, which is predominantly caused by **viral infections**, not bacterial. Therefore, antibiotics like parenteral cefotaxime are generally **not indicated**. - **Cefotaxime** is a broad-spectrum antibiotic used for serious bacterial infections; its use in viral croup would be inappropriate and could contribute to antibiotic resistance. *Nebulized racemic epinephrine* - **Nebulized racemic epinephrine** is a common and effective treatment for moderate to severe croup, as it helps to **vasoconstrict** the subglottic mucosa, reducing edema and improving airflow. - It provides temporary relief from symptoms, especially stridor, by reducing swelling in the airway. *Intramuscular dexamethasone* - **Dexamethasone**, a corticosteroid, is a cornerstone of croup treatment as it reduces inflammation and edema in the airway, improving respiratory symptoms. - It can be administered orally, intravenously, or intramuscularly, and provides sustained relief, typically for 24-48 hours. *Nebulized budesonide* - **Nebulized budesonide** is an alternative corticosteroid treatment for croup that delivers anti-inflammatory medication directly to the airway. - Studies show it is equally effective to dexamethasone for mild to moderate croup, though dexamethasone is often preferred due to ease of administration and longer duration of action. *Helium oxygen mixture* - A **helium-oxygen mixture (heliox)** is a therapeutic gas that is less dense than air, which can reduce the work of breathing in patients with severe airway obstruction, such as refractory croup. - By decreasing airway turbulence, heliox can temporarily improve air movement past the narrowed subglottic area.
Question 6: Koplik spots are pathognomonic of which of the following?
- A. Diphtheria
- B. Donovanosis
- C. Gonorrhoea
- D. Measles (Correct Answer)
Explanation: ***Measles*** - **Koplik spots** are small, white spots with a bluish-white center on an erythematous base, found on the buccal mucosa opposite the molars. - They are a **pathognomonic sign** of measles (rubeola) and typically appear 1-2 days before the generalized maculopapular rash. *Diphtheria* - Characterized by the formation of a **thick, grayish membrane (pseudomembrane)** in the throat and tonsils, which can cause respiratory obstruction. - It is caused by **_Corynebacterium diphtheriae_** and does not present with Koplik spots. *Donovanosis* - This is a chronic, progressive **genital ulcerative disease** caused by **_Klebsiella granulomatis_**. - It presents with **beefy-red, granulomatous lesions** on the genitals or perineum and has no association with oral lesions like Koplik spots. *Gonorrhea* - A **sexually transmitted infection** caused by **_Neisseria gonorrhoeae_**, primarily affecting the urethra, cervix, rectum, and pharynx. - Oral manifestations can include pharyngitis, but **Koplik spots are not a feature** of gonorrhea.
Question 7: A 4-year-old child with barking cough is diagnosed with croup. Which virus is most likely responsible?
- A. Parainfluenza virus (Correct Answer)
- B. Rhinovirus
- C. Adenovirus
- D. Respiratory syncytial virus
Explanation: ***Parainfluenza virus*** - **Parainfluenza viruses (PIV)** are the most common cause of **croup**, characterized by a **barking cough**, hoarseness, and inspiratory stridor. - PIV types 1 and 2 are particularly associated with acute laryngotracheobronchitis (croup) in young children. *Rhinovirus* - **Rhinoviruses** are the primary cause of the **common cold** and typically result in upper respiratory tract symptoms like runny nose, sneezing, and sore throat. - They are generally not associated with the severe laryngeal inflammation that causes the characteristic barking cough of croup. *Adenovirus* - **Adenoviruses** can cause a variety of respiratory illnesses, including pharyngitis and pneumonia, and sometimes mimic croup. - However, they are a less frequent cause of croup compared to parainfluenza viruses. *Respiratory syncytial virus* - **Respiratory syncytial virus (RSV)** is the leading cause of **bronchiolitis** and pneumonia in infants and young children. - While RSV can cause upper respiratory symptoms, it typically leads to wheezing and crackles rather than the barking cough of croup.
Question 8: All of the following are RNA viruses except
- A. Influenza virus
- B. Parainfluenza virus
- C. Mumps virus
- D. Herpes virus (Correct Answer)
Explanation: ***Herpes virus*** - **Herpesviruses** are a large family of **DNA viruses** that cause diseases in animals, including humans. - They are characterized by their ability to establish **latent infections** and periodically reactivate. *Influenza virus* - The **influenza virus** is an **RNA virus** belonging to the family **Orthomyxoviridae**. - It is known for causing the seasonal **flu** and respiratory infections. *Parainfluenza virus* - **Parainfluenza viruses** are a group of **RNA viruses** in the family **Paramyxoviridae**. - They are a common cause of **respiratory tract infections**, especially in children, leading to conditions like **croup**. *Mumps virus* - The **mumps virus** is an **RNA virus** that is part of the **Paramyxoviridae** family. - It is well-known for causing **mumps**, which is characterized by the swelling of the **parotid glands**.
Question 9: Which of the following statements about paramyxoviruses is false?
- A. Belong to the family Paramyxoviridae
- B. Are DNA viruses (Correct Answer)
- C. Are RNA viruses
- D. Have linear nucleic acid
Explanation: ***Are DNA viruses*** - Paramyxoviruses are characterized by their **single-stranded, negative-sense RNA genome**, not DNA. - Their replication and transcription processes occur in the cytoplasm, which is typical for RNA viruses. *Belong to the family Paramyxoviridae* - This statement is correct; paramyxoviruses are indeed classified under the **family Paramyxoviridae**. - This family includes important human pathogens like measles, mumps, and respiratory syncytial virus (RSV). *Have linear nucleic acid* - This statement is correct as paramyxoviruses possess a **linear, non-segmented RNA genome**. - The linear nature differentiates them from viruses with segmented genomes, such as influenza viruses. *Are RNA viruses* - This statement is correct; paramyxoviruses are characterized by their **RNA genome**. - Specifically, they are **negative-sense, single-stranded RNA viruses**.
Question 10: Which of the following is an RNA oncogenic virus?
- A. Cytomegalovirus (CMV)
- B. Hepatitis B Virus (HBV)
- C. Human T-lymphotropic Virus (HTLV) (Correct Answer)
- D. Human Immunodeficiency Virus (HIV)
Explanation: ***Human T-lymphotropic Virus (HTLV)*** - **HTLV-1** is a well-established **RNA oncogenic virus** that causes Adult T-cell Leukemia/Lymphoma (ATLL). - It utilizes **reverse transcriptase** to convert its RNA genome into DNA, which then integrates into the host cell's genome, leading to malignant transformation. *Cytomegalovirus (CMV)* - CMV is a **DNA virus** and belongs to the Herpesviridae family. - While it can cause disease, it is not primarily classified as an **oncogenic virus**, although some studies suggest associations with certain cancers. *Hepatitis B Virus (HBV)* - HBV is a **DNA virus** that primarily causes acute and chronic hepatitis. - It is a major risk factor for **hepatocellular carcinoma (HCC)**, but it itself is a DNA virus, not an RNA virus. *Human Immunodeficiency Virus (HIV)* - HIV is an **RNA retrovirus**, but it is generally considered **non-oncogenic** in the direct sense. - While HIV-infected individuals have an increased risk of certain cancers (e.g., Kaposi's sarcoma, non-Hodgkin lymphoma), these are usually due to **immunosuppression** allowing co-infecting oncogenic viruses (like HHV-8 or EBV) to proliferate, rather than direct oncogenic action of HIV itself.
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