Infectious Diseases Practice Questions

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.

Q: Which infection is most likely associated with this type of eye problem in children?

Rubella. The correct answer is **Rubella**, specifically in the context of **Congenital Rubella Syndrome (CRS)**. ### **Explanation of the Correct Answer** Rubella is a classic cause of congenital eye defects. When a mother is infected during the first trimester, the virus interferes with organogenesis. The most characteristic eye finding is a **"Pearlescent" Nuclear Cataract** (often bilateral). Other ocular manifestations include **"Salt and Pepper" Retinopathy** (the most common ocular finding), microphthalmos, and infantile glaucoma. The classic Gregg’s Triad for CRS includes: 1. **Cataracts** (Eye) 2. **Sensorineural Hearing Loss** (Ear - Most common overall) 3. **Congenital Heart Disease** (Heart - Patent Ductus Arteriosus or Peripheral Pulmonary Artery Stenosis) ### **Why Other Options are Incorrect** * **Typhoid:** Primarily a systemic gastrointestinal illness. While it can cause "Rose spots" on the trunk, it does not typically cause congenital or acute pediatric eye malformations. * **HIV:** Pediatric HIV usually presents with opportunistic infections, failure to thrive, or lymphadenopathy. While CMV retinitis can occur in advanced stages, it is not a primary association for structural eye defects in children. * **Measles:** While Measles is famous for **Koplik spots** and can cause severe **keratitis** leading to blindness (especially in Vitamin A deficient children), it does not cause the congenital structural defects (like cataracts) associated with Rubella. ### **High-Yield Clinical Pearls for NEET-PG** * **Most common finding in CRS:** Sensorineural deafness. * **Most common ocular finding in CRS:** Salt and Pepper Retinopathy (does not significantly affect vision). * **Most specific ocular finding:** Pearlescent nuclear cataract. * **Dermal Erythropoiesis:** Leads to the "Blueberry Muffin" rash (also seen in CMV). * **Diagnosis:** Confirmed by Rubella-specific IgM in the newborn or persistent IgG levels beyond 6 months.

Q: A line of conjunctival inflammation on the lower eyelid margin is diagnostic of which condition?

Measles. **Explanation:** The correct answer is **Measles (Rubeola)**. The specific clinical sign described is known as **Stimson’s line**. It is a transverse line of conjunctival inflammation/hyperemia appearing along the margin of the lower eyelid during the prodromal phase of Measles. **Why Measles is correct:** Measles is characterized by a distinct prodromal phase consisting of the "3 Cs": **C**ough, **C**oryza, and **C**onjunctivitis. Stimson’s line is one of the earliest signs of the disease, appearing even before the pathognomonic **Koplik spots** (found on the buccal mucosa opposite the lower second molars). **Why other options are incorrect:** * **Rubella (German Measles):** While it presents with a rash and lymphadenopathy (retroauricular/suboccipital), it typically features **Forchheimer spots** (petechiae on the soft palate) rather than Stimson’s line. * **Kawasaki Disease:** This condition presents with **bilateral non-exudative conjunctival injection** (sparing the limbus), but it does not manifest as a specific line on the lower eyelid margin. * **Infectious Mononucleosis:** This is associated with exudative pharyngitis, lymphadenopathy, and hepatosplenomegaly. A common ocular finding is **Hoagland sign** (early transient bilateral upper eyelid edema), not Stimson’s line. **High-Yield Clinical Pearls for NEET-PG:** * **Stimson’s Line:** Earliest ocular sign of Measles. * **Koplik Spots:** Pathognomonic for Measles; appear 48 hours before the rash. * **Vitamin A:** Supplementation is mandatory in Measles management to prevent complications like blindness and pneumonia. * **Order of disappearance:** Koplik spots disappear as the maculopapular rash appears (which spreads in a cephalocaudal direction).

Q: Which of the following is NOT a neurological complication of rubeola?

Peripheral neuropathy. **Explanation:** Rubeola (Measles) is a highly contagious viral infection known for its significant neurotropism. While it primarily affects the respiratory system, it can cause various central nervous system (CNS) complications. **Why Peripheral Neuropathy is the correct answer:** Peripheral neuropathy is **not** a recognized complication of rubeola. Measles complications typically involve the CNS (brain and spinal cord) rather than the peripheral nerves. Conditions like Guillain-Barré Syndrome (a peripheral nerve issue) are more commonly associated with viruses like Campylobacter jejuni, CMV, or Zika, but not classically with Measles. **Analysis of Incorrect Options:** * **Subacute Sclerosing Panencephalitis (SSPE):** A rare, fatal, late complication occurring 7–10 years after infection. It is caused by a persistent mutant measles virus and is characterized by cognitive decline, myoclonic jerks, and periodic complexes on EEG. * **Encephalitis:** This can occur in two forms: **Acute Disseminated Encephalomyelitis (ADEM)**, an immune-mediated demyelinating disease occurring 1–2 weeks after the rash, and **Measles Inclusion Body Encephalitis (MIBE)**, which occurs in immunocompromised individuals. * **Transverse Myelitis:** Though rare, measles can trigger an inflammatory response in the spinal cord, leading to acute transverse myelitis. **High-Yield Clinical Pearls for NEET-PG:** * **Most common complication of Measles:** Otitis media. * **Most common cause of death in Measles:** Pneumonia (Hecht’s giant cell pneumonia). * **SSPE Marker:** Elevated anti-measles antibody titers in the CSF and serum. * **Vitamin A:** Supplementation reduces morbidity and mortality in all children with acute measles.

Question 1

Which is the most common complication of this rash?

Accepted Answer

Secondary skin infections

Answer

Otitis media

Answer

Bronchopneumonia

Answer

Reye syndrome

Question 2

Which of the following is NOT a complication of chickenpox?

Accepted Answer

Enteritis

Answer

Meningitis

Answer

Pneumonia

Answer

Reye's Syndrome

Question 3

Parotitis and orchitis are common manifestations of which disease?

Accepted Answer

Mumps

Answer

Diphtheria

Answer

Measles

Answer

Rubella

Question 4

Paralysis in polio is characterized by?

Accepted Answer

Lower motor neurone type

Answer

Exaggerated tendon reflexes

Answer

Symmetrical paralysis

Answer

Tonic paralysis

Question 5

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 6

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

Question 7

Which infection is most likely associated with this type of eye problem in children?

Accepted Answer

Rubella

Answer

Typhoid

Answer

HIV

Answer

Measles

Question 8

A line of conjunctival inflammation on the lower eyelid margin is diagnostic of which condition?

Accepted Answer

Measles

Answer

Rubella

Answer

Kawasaki disease

Answer

Infectious mononucleosis

Question 9

Which of the following is NOT a neurological complication of rubeola?

Accepted Answer

Peripheral neuropathy

Answer

Subacute sclerosing panencephalitis (SSPE)

Answer

Encephalitis

Answer

Transverse myelitis

Question 10

Absolute contraindications to pertussis vaccine include all of the following except?

Accepted Answer

Static neurological disease

Answer

Progressive neurological disease

Answer

Anaphylaxis after previous dose

Answer

Encephalopathy within seven days of previous dose

Infectious Diseases — MCQs

Infectious Diseases — MCQs

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