Diseases of the Conjunctiva Practice Questions

Q: New Castle conjunctivitis is caused by contact with diseased:

Owls. **Explanation:** **Newcastle Disease Conjunctivitis** is a viral infection caused by the **Newcastle Disease Virus (NDV)**, which belongs to the *Paramyxoviridae* family. While primarily a highly contagious and fatal systemic disease in birds (poultry), it can be transmitted to humans through direct contact with infected avian species. 1. **Why Owls is the correct answer:** Among the options provided, **owls** (and birds in general) are the natural reservoirs for this virus. In humans, the infection typically occurs in laboratory workers, veterinarians, or poultry handlers. It manifests as a self-limiting, acute follicular conjunctivitis, often accompanied by preauricular lymphadenopathy and mild flu-like symptoms. 2. **Why other options are incorrect:** * **Dogs & Cats:** These animals are associated with different ophthalmic zoonoses, such as *Toxocara canis/cati* (Ocular Larva Migrans) or *Bartonella henselae* (Parinaud Oculoglandular Syndrome from cat scratches). They do not carry the Newcastle Disease Virus. * **Horses:** While horses can transmit certain infections, they are not hosts for NDV. **High-Yield Clinical Pearls for NEET-PG:** * **Type of Conjunctivitis:** It is a **Follicular conjunctivitis**. * **Transmission:** Direct contact with infected birds or live-virus vaccines used in poultry. * **Clinical Course:** Usually unilateral, mild, and resolves spontaneously within 7–10 days without permanent ocular damage. * **Differential Diagnosis:** Must be distinguished from other viral follicular conjunctivitis like Adenovirus (EKC/PCF), which is much more common and severe.

Q: Which of the following is NOT a feature of vernal conjunctivitis?

Herpes pits, pannus & follicles. **Explanation:** Vernal Keratoconjunctivitis (VKC) is a bilateral, recurrent, seasonal allergic inflammation of the conjunctiva, primarily affecting young males. It is a **Type I and Type IV hypersensitivity reaction**. **Why Option D is the Correct Answer:** **Herbert’s pits, pannus, and follicles** are hallmark features of **Trachoma** (caused by *Chlamydia trachomatis*), not VKC. * **Herbert’s pits:** Scarred remains of follicles at the limbus. * **Pannus:** Vascularization and infiltration of the upper cornea. * **Follicles:** Lymphoid aggregations typically seen in the upper palpebral conjunctiva in Trachoma. In contrast, VKC is characterized by **papillae**, not follicles. **Analysis of Incorrect Options (Features of VKC):** * **A. Shield Ulcer:** A sterile, transverse oval corneal ulcer in the upper cornea caused by mechanical rubbing of giant papillae and chemical mediators. * **B. Horner-Tranta’s Spots:** Small, white, elevated dots at the limbus consisting of eosinophils and epithelial debris; pathognomonic for the limbal form of VKC. * **C. Papillary Hypertrophy:** The hallmark of the palpebral form, leading to a "cobblestone" or "pavement stone" appearance of the superior tarsal conjunctiva. **High-Yield Clinical Pearls for NEET-PG:** * **Demographics:** "Spring catarrh"; more common in hot, dry climates. * **Symptoms:** Intense itching (most common), ropy discharge, and photophobia. * **Maxwell-Lyons Sign:** A thin film of fibrin (pseudomembrane) covering the papillae. * **Treatment:** Mast cell stabilizers (Cromolyn), antihistamines, and topical steroids for acute flares. Avoid long-term steroids due to glaucoma/cataract risk.

Q: Pseudomembranous conjunctivitis is caused by which organism?

All of the above. **Explanation:** **Pseudomembranous conjunctivitis** is a type of acute conjunctivitis characterized by the formation of a "false membrane" on the palpebral conjunctiva. This membrane consists of coagulated exudate, fibrin, and inflammatory cells loosely attached to the epithelium, which can be peeled off without causing significant bleeding (unlike true membranes). **Why "All of the above" is correct:** Pseudomembranous conjunctivitis is an inflammatory response to various infectious agents of varying virulence. * **Streptococcus pyogenes:** Historically the most common cause of pseudomembrane formation. * **Staphylococcus aureus:** A frequent cause of acute mucopurulent conjunctivitis that can progress to pseudomembrane formation in severe cases. * **Neisseria gonorrhoeae:** Known for causing hyperacute purulent conjunctivitis; the intense inflammatory reaction often leads to the formation of pseudomembranes. Other common causes include **Adenovirus** (Epidemic Keratoconjunctivitis - Serotypes 8, 19, 37) and **Corynebacterium xerosis**. **Clinical Pearls for NEET-PG:** 1. **True Membrane vs. Pseudomembrane:** The hallmark of a **True Membrane** (caused primarily by *Corynebacterium diphtheriae*) is that it is firmly adherent; removal results in a raw, bleeding surface. 2. **Adenoviral Conjunctivitis:** This is the most common cause of pseudomembranes in modern clinical practice, often associated with preauricular lymphadenopathy. 3. **Treatment:** Management involves gentle removal of the membrane to prevent symblepharon formation and intensive topical antibiotics or antivirals based on the underlying etiology. 4. **Ligneous Conjunctivitis:** A rare, chronic form of pseudomembranous conjunctivitis caused by **Plasminogen deficiency**, leading to "wood-like" induration of the lids.

Q: Bowen's disease is characterized by all of the following features except:

Poikilocytosis. **Explanation:** Bowen’s Disease of the conjunctiva, also known as **Conjunctival Intraepithelial Neoplasia (CIN)**, is a pre-invasive squamous cell carcinoma. **Why Poikilocytosis is the correct answer:** **Poikilocytosis** refers to the presence of abnormally shaped red blood cells (RBCs) in a blood film, which is a hematological finding (e.g., in anemias). It has no association with ocular pathology or Bowen’s disease. The term often confused with this in histopathology is **Poikilocytosis vs. Pleomorphism**; Bowen’s disease is characterized by cellular pleomorphism (variation in size and shape of cells), not poikilocytosis. **Analysis of other options:** * **Predilection for the limbus:** This is a classic feature. CIN most commonly arises at the limbus within the interpalpebral fissure, as this area is most exposed to UV radiation. * **Presence of monster cells:** Histologically, Bowen’s disease shows "Bizarre" or "Monster" cells, which are giant, multinucleated, or hyperchromatic cells representing extreme cellular atypia. * **Incapacity to metastasize:** By definition, Bowen’s disease is a **carcinoma-in-situ**. The atypical cells are confined to the epithelium and have not breached the basement membrane. Therefore, it lacks the capacity to metastasize unless it progresses into invasive squamous cell carcinoma. **High-Yield Clinical Pearls for NEET-PG:** * **Appearance:** Often presents as a fleshy, grey-white, "frosted" or gelatinous plaque with "corkscrew" surface vessels. * **Histology:** Shows "Acanthosis," "Dyskeratosis" (premature keratinization), and a "Full-thickness replacement" of epithelium by atypical cells. * **Management:** Surgical excision with "No-touch technique" and cryotherapy to the margins; topical Mitomycin-C or Interferon alpha-2b are used as adjunctive therapies.

Q: A patient presents with a yellowish-white patch on the bulbar conjunctiva near the limbus. Which of the following statements regarding this condition is false?

It is always unilateral.. The clinical presentation describes a **Pinguecula**, a common, non-cancerous growth of the conjunctiva. ### **Explanation of Options** * **Option B (Correct Answer):** Pinguecula is typically **bilateral**, though it may be asymmetrical. It is a degenerative condition caused by chronic exposure to UV light, wind, and dust; since these environmental factors affect both eyes, the condition is rarely strictly unilateral. * **Option A:** The hallmark histopathology of pinguecula is **elastotic degeneration** of the collagen fibers within the substantia propria (stroma) of the conjunctiva, accompanied by the deposition of amorphous hyaline material. * **Option C:** While most cases are asymptomatic and require no treatment (or simple lubrication), **excision** is the definitive treatment if the lesion becomes chronically inflamed (pingueculitis) or causes significant cosmetic concern. * **Option D:** Although they are distinct entities, a pinguecula can occasionally serve as a precursor or "lead" to the development of a **pterygium**, where the growth crosses the limbus onto the cornea. ### **High-Yield Clinical Pearls for NEET-PG** * **Location:** Most commonly found on the **nasal side** (due to reflection of UV rays from the nose). * **Appearance:** A yellowish-white, triangular, or nodular patch near the limbus that **does not** involve the cornea (unlike pterygium). * **Histology:** Look for "elastotic degeneration"—this is a frequent buzzword in exams. * **Stockard’s Line:** An iron line sometimes seen at the leading edge of a pterygium (not pinguecula), indicating stability. * **Differential Diagnosis:** Must be distinguished from a Bitot’s spot (associated with Vitamin A deficiency), which has a "foamy" appearance and is composed of keratinized epithelium.

Q: Ophthalmia neonatorum presenting within 24 hours of birth is most likely due to which of the following?

Chemical inoculation. **Explanation:** **Ophthalmia neonatorum** is defined as any discharge or inflammation of the conjunctiva occurring within the first month of life. The timing of the onset is the most critical diagnostic clue for identifying the causative agent in NEET-PG questions. **Why Chemical Inoculation is correct:** Chemical conjunctivitis is the earliest possible cause, typically appearing **within the first 24 hours** of birth. Historically, this was most commonly associated with the use of **Silver Nitrate (Credé's prophylaxis)** for the prevention of gonococcal infection. It presents as mild conjunctival hyperemia and watering, which is self-limiting and usually resolves within 48 hours without treatment. **Why the other options are incorrect:** * **Herpes Simplex (B):** Typically presents later, usually between **1 to 2 weeks** after birth. It is often associated with systemic involvement or vesicular skin lesions. * **Staphylococcus (C) and Haemophilus (D):** These are causes of bacterial conjunctivitis that generally manifest between **5 days to 2 weeks** of life. **High-Yield Clinical Pearls for NEET-PG:** The "Incubation Period Timeline" is a frequent exam favorite: * ** 2 weeks:** Herpes Simplex Virus (Type II). **Management Note:** For *Chlamydia*, oral Erythromycin is the treatment of choice to prevent associated infantile pneumonia. For *Gonorrhea*, systemic Ceftriaxone is required.

Q: Which of the following is NOT a recommended treatment for ophthalmia neonatorum?

Silver nitrate. **Explanation:** The correct answer is **Silver nitrate**. Historically, 1% silver nitrate was used as prophylaxis against ophthalmia neonatorum (Credé’s method). However, it is **no longer recommended** for treatment or prophylaxis because it frequently causes **chemical conjunctivitis** (occurring within 6–24 hours of application) and is ineffective against *Chlamydia trachomatis*, the most common cause of neonatal conjunctivitis today. **Analysis of Options:** * **A & B (Erythromycin and Tetracycline):** These are currently the preferred topical agents for both prophylaxis and as adjuncts in treatment. Erythromycin ointment (0.5%) and Tetracycline (1%) are effective against most bacterial pathogens, including *Chlamydia* and *Staphylococcus*. * **C (Penicillin locally):** While systemic penicillin is the mainstay for *Neisseria gonorrhoeae*, local penicillin drops were traditionally used. However, due to the high risk of sensitization and the emergence of penicillinase-producing strains, its use has diminished, but it remains a recognized pharmacological treatment compared to the toxic chemical nature of silver nitrate. **High-Yield Clinical Pearls for NEET-PG:** * **Definition:** Conjunctivitis occurring within the first 30 days of life. * **Incubation Periods (Crucial for Exams):** * **Chemical (Silver Nitrate):** 6–24 hours. * **Gonococcal:** 2–5 days (Most destructive; can cause corneal perforation). * **Chlamydia (TRIC agent):** 5–14 days (Most common cause). * **Herpes Simplex:** 1–2 weeks. * **Treatment of Choice:** For *Chlamydia*, oral Erythromycin is mandatory to prevent subsequent chlamydial pneumonia. For *Gonococcus*, systemic Ceftriaxone is the gold standard.

Q: What is the most common cause of ophthalmia neonatorum?

Chlamydia. **Explanation:** **Ophthalmia Neonatorum** is defined as any conjunctivitis occurring within the first 30 days of life. **1. Why Chlamydia is Correct:** *Chlamydia trachomatis* (Serotypes D-K) is globally recognized as the **most common cause** of ophthalmia neonatorum. It typically presents 5 to 14 days after birth. The infection is acquired during passage through an infected birth canal. It is characterized by mucopurulent discharge and, if left untreated, can lead to conjunctival scarring and corneal pannus. Notably, it is also associated with systemic involvement, such as neonatal pneumonia. **2. Why the other options are incorrect:** * **B. Gonorrhoea:** *Neisseria gonorrhoeae* is the **most hyperacute and vision-threatening** cause, but it is less common than Chlamydia due to routine prenatal screening. It typically presents earlier (2–5 days) with profuse, thick purulent discharge and carries a high risk of corneal perforation. * **C. Herpes Simplex Virus (HSV):** HSV-2 is a viral cause presenting between 1–2 weeks. It is characterized by vesicular skin lesions and dendritic keratitis but is significantly rarer than bacterial causes. * **D. Staphylococcus aureus:** While a common cause of skin infections, it is a less frequent cause of neonatal conjunctivitis compared to the specialized pathogens acquired from the maternal genital tract. **High-Yield Clinical Pearls for NEET-PG:** * **Chemical Conjunctivitis:** Occurs within the first 24 hours (usually due to Silver Nitrate prophylaxis). * **Incubation Periods (High Yield):** * Chemical: <24 hours * Gonococcal: 2–5 days * Chlamydial: 5–14 days * **Treatment:** Systemic Erythromycin is the drug of choice for Chlamydial ophthalmia to prevent associated pneumonia. Topical treatment alone is insufficient. * **Prophylaxis:** Povidone-iodine (5%) or Erythromycin ointment is currently preferred over the historical Credé’s method (Silver Nitrate).

Q: Epidemic hemorrhagic conjunctivitis is caused by which virus?

Picornavirus. **Explanation:** **Epidemic Hemorrhagic Conjunctivitis (EHC)** is a highly contagious, self-limiting viral infection characterized by sudden onset of follicular conjunctivitis and prominent **subconjunctival hemorrhages**. **Why Picornavirus is correct:** EHC is primarily caused by two specific viruses belonging to the **Picornaviridae** family: **Enterovirus 70 (EV-70)** and **Coxsackievirus A24 (CA24)**. These are small, non-enveloped RNA viruses. The condition is often referred to as "Apollo Conjunctivitis" because it was first recognized in 1969 (the year of the Apollo 11 moon landing). It spreads rapidly via the feco-oral route or direct contact with ocular secretions. **Why other options are incorrect:** * **HSV & HZV:** While both can cause conjunctivitis, they are more typically associated with **keratitis** (dendritic ulcers in HSV; pseudodendrites in HZV). They do not cause large-scale epidemics of hemorrhagic conjunctivitis. * **HIV:** HIV is not a primary cause of acute conjunctivitis. However, patients with HIV are more prone to opportunistic infections (like CMV retinitis) or Kaposi sarcoma of the conjunctiva. **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Period:** Very short (12–48 hours). * **Key Sign:** Multiple petechial hemorrhages that may coalesce to involve the entire bulbar conjunctiva. * **Neurological Association:** Enterovirus 70 is rarely associated with a polio-like **radiculomyelitis** (cranial nerve palsies or lower limb paralysis). * **Differential Diagnosis:** Adenovirus (Serotypes 8, 11, 19) causes Epidemic Keratoconjunctivitis (EKC), which presents with significant corneal involvement (subepithelial infiltrates) rather than primary hemorrhage.

Q: Unilateral watery discharge from the eye of a newborn, with no edema or chemosis, is due to which of the following?

Chemical conjunctivitis. **Explanation:** The correct answer is **Chemical conjunctivitis**. This condition is typically the earliest form of ophthalmia neonatorum, appearing within the first **6–24 hours** of life. It is historically associated with the use of **Silver Nitrate (Crede’s method)** or prophylactic antibiotics like erythromycin. **Why it is correct:** Chemical conjunctivitis presents as a **mild, unilateral or bilateral watery discharge** with conjunctival hyperemia. Crucially, it lacks the severe inflammatory signs like chemosis (swelling of the conjunctiva) or lid edema, which are hallmarks of bacterial infections. It is a self-limiting condition that resolves spontaneously within 48 hours without treatment. **Why other options are incorrect:** * **Chlamydia trachomatis:** This is the most common cause of neonatal conjunctivitis globally. However, it typically appears **5–14 days** after birth and presents with significant mucopurulent discharge and lid swelling. * **Neisseria gonorrhoeae:** This is the most **hyperacute and vision-threatening** cause, appearing **2–5 days** after birth. It is characterized by profuse, thick purulent discharge, severe chemosis, and a high risk of corneal perforation. * **Mucoid discharge (Sticky eye):** This is a clinical sign rather than a specific diagnosis. While it can be seen in various infections, the absence of edema and the "watery" nature specifically point toward a chemical etiology in the immediate postnatal period. **High-Yield Clinical Pearls for NEET-PG:** * **Timeline of Ophthalmia Neonatorum:** * ** 2 weeks:** Herpes Simplex (HSV-2). * **Prophylaxis:** Povidone-iodine (5%) is now preferred over Silver Nitrate as it is less irritating and covers both bacteria and viruses.

Question 1

New Castle conjunctivitis is caused by contact with diseased:

Accepted Answer

Owls

Answer

Dogs

Answer

Cats

Answer

Horses

Question 2

Which of the following is NOT a feature of vernal conjunctivitis?

Accepted Answer

Herpes pits, pannus & follicles

Answer

Shield ulcer

Answer

Horner-Tranta's spots

Answer

Papillary hypertrophy

Question 3

Pseudomembranous conjunctivitis is caused by which organism?

Accepted Answer

All of the above

Answer

Neisseria gonorrhoeae

Answer

Staphylococcus aureus

Answer

Streptococcus pyogenes

Question 4

Bowen's disease is characterized by all of the following features except:

Accepted Answer

Poikilocytosis

Answer

Predilection for the limbus

Answer

Presence of monster cells

Answer

Incapacity to metastasize

Question 5

A patient presents with a yellowish-white patch on the bulbar conjunctiva near the limbus. Which of the following statements regarding this condition is false?

Accepted Answer

It is always unilateral.

Answer

There is elastotic degeneration of the substantia propria.

Answer

The treatment is excision.

Answer

It may rarely undergo conversion into a pterygium.

Question 6

Ophthalmia neonatorum presenting within 24 hours of birth is most likely due to which of the following?

Accepted Answer

Chemical inoculation

Answer

Herpes simplex

Answer

Staphylococcus

Answer

Haemophilus influenzae

Question 7

Which of the following is NOT a recommended treatment for ophthalmia neonatorum?

Accepted Answer

Silver nitrate

Answer

Erythromycin locally

Answer

Tetracycline 1%

Answer

Penicillin locally

Question 8

What is the most common cause of ophthalmia neonatorum?

Accepted Answer

Chlamydia

Answer

Gonorrhoea

Answer

Herpes Simplex Virus (HSV)

Answer

Staphylococcus aureus

Question 9

Epidemic hemorrhagic conjunctivitis is caused by which virus?

Accepted Answer

Picornavirus

Answer

Herpes Simplex Virus (HSV)

Answer

Herpes Zoster Virus (HZV)

Answer

Human Immunodeficiency Virus (HIV)

Question 10

Unilateral watery discharge from the eye of a newborn, with no edema or chemosis, is due to which of the following?

Accepted Answer

Chemical conjunctivitis

Answer

Chlamydia trachomatis

Answer

Neisseria gonorrhoeae

Answer

Mucoid discharge (sticky eye)

Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva — MCQs

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