Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva Indian Medical PG Practice Questions and MCQs

Question 211: Ophthalmia neonatorum is caused by which of the following agents?

A. Neisseria gonorrhoeae, Haemophilus influenzae, Chlamydia trachomatis, Pseudomonas aeruginosa (Correct Answer)
B. Haemophilus influenzae, Pseudomonas aeruginosa, Staphylococcus aureus
C. Neisseria gonorrhoeae, Haemophilus influenzae, Chlamydia trachomatis, Staphylococcus aureus
D. Neisseria gonorrhoeae, Haemophilus influenzae, Pseudomonas aeruginosa, Staphylococcus aureus

Explanation: **Explanation:** **Ophthalmia Neonatorum** is defined as any discharge or inflammation of the conjunctiva occurring within the first 30 days of life. It is a medical emergency because certain causative agents can lead to rapid corneal perforation and permanent blindness. **Why Option A is Correct:** The correct answer includes the most significant and classic pathogens associated with neonatal conjunctivitis. * **Chlamydia trachomatis (Serotypes D-K):** The most common bacterial cause worldwide. * **Neisseria gonorrhoeae:** The most serious cause, capable of penetrating intact corneal epithelium, leading to rapid perforation. * **Pseudomonas aeruginosa:** A highly virulent organism often associated with hospital-acquired infections (NICU stays), causing rapid corneal liquefaction. * **Haemophilus influenzae:** A known pediatric pathogen that can cause acute mucopurulent conjunctivitis in neonates. **Analysis of Incorrect Options:** Options B, C, and D are incorrect because they include **Staphylococcus aureus**. While *S. aureus* is a common cause of adult conjunctivitis and can occasionally be found in neonates, it is generally considered a "commensal" or a secondary invader rather than a primary, classic agent of Ophthalmia Neonatorum in the context of standard medical examinations. Option A represents the specific "high-risk" group of pathogens traditionally tested in the NEET-PG curriculum. **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Periods (Crucial for Diagnosis):** * **Chemical (Silver Nitrate):** 0–24 hours. * **Neisseria gonorrhoeae:** 2–5 days (Hyperacute presentation). * **Chlamydia trachomatis:** 5–14 days (Most common). * **Herpes Simplex (HSV-2):** 5–15 days. * **Prophylaxis:** 1% Silver nitrate (Credé's method—now largely historical) or 0.5% Erythromycin ointment. * **Treatment:** *Neisseria* requires systemic Ceftriaxone; *Chlamydia* requires systemic Erythromycin (to prevent Chlamydial pneumonia).

Question 212: Which of the following does NOT cause conjunctivitis?

A. Adenovirus
B. Enterovirus
C. Coxsackie virus
D. None of the above (Correct Answer)

Explanation: **Explanation:** The correct answer is **None of the above** because all three viruses listed—Adenovirus, Enterovirus, and Coxsackie virus—are well-documented causes of viral conjunctivitis. 1. **Adenovirus (Option A):** This is the most common cause of viral conjunctivitis worldwide. It typically presents in two clinical forms: **Pharyngoconjunctival Fever (PCF)**, caused by serotypes 3, 4, and 7, and **Epidemic Keratoconjunctivitis (EKC)**, caused by serotypes 8, 11, 19, and 37. EKC is more severe and often involves corneal subepithelial infiltrates. 2. **Enterovirus and Coxsackie virus (Options B & C):** These are the primary causative agents of **Acute Hemorrhagic Conjunctivitis (AHC)**. Specifically, **Enterovirus 70** and **Coxsackie virus A24** are notorious for causing explosive outbreaks characterized by rapid onset, lid edema, and pathognomonic subconjunctival hemorrhages. **Clinical Pearls for NEET-PG:** * **Follicular Reaction:** Viral conjunctivitis typically presents with a follicular response in the inferior palpebral conjunctiva. * **Preauricular Lymphadenopathy:** This is a hallmark sign of viral conjunctivitis (especially Adenoviral), helping to differentiate it from bacterial causes. * **Transmission:** These viruses are highly contagious and spread via respiratory droplets or direct finger-to-eye contact (fomites). * **Treatment:** Most viral conjunctivitis is self-limiting; management is primarily supportive (cold compresses and artificial tears). Steroids are generally avoided in the acute phase unless significant subepithelial infiltrates affect vision.

Question 213: Phlyctenular conjunctivitis is most commonly seen due to which of the following?

A. Fungal infection
B. Allergic reaction (Correct Answer)
C. Protozoal infection
D. Tuberculoid reaction

Explanation: **Explanation:** **Phlyctenular Keratoconjunctivitis** is a localized **Type IV (delayed) hypersensitivity reaction** of the conjunctiva and cornea to endogenous microbial proteins. 1. **Why "Allergic reaction" is correct:** The condition is not a direct infection but an **allergic response** to a previous sensitization. The body reacts to bacterial antigens (most commonly **Staphylococcus aureus** in developed countries and **Mycobacterium tuberculosis** in developing countries). The characteristic lesion, the "phlycten," is a lymphocytic nodule that represents this cell-mediated immune response. 2. **Why the other options are incorrect:** * **Fungal and Protozoal infections:** These are direct invasions of the ocular tissue by pathogens. Phlyctenulosis is an immunological phenomenon, not a primary infection by these organisms. * **Tuberculoid reaction:** While Tuberculosis is a major causative agent, the term "tuberculoid reaction" is non-specific and often associated with leprosy. The underlying mechanism across all triggers (TB, Staph, Moraxella) is a Type IV allergic reaction. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause (India):** Tuberculosis. * **Most common cause (Worldwide):** Staphylococcus aureus. * **Clinical Presentation:** Intense photophobia (especially if the cornea is involved), lacrimation, and the presence of a small, pinkish-white nodule near the limbus surrounded by localized hyperemia. * **The "Fascicular Ulcer":** A specific type of corneal phlycten that migrates from the limbus toward the center, carrying a leash of blood vessels behind it. * **Treatment:** Topical steroids (to control the allergic response) and treatment of the underlying cause (e.g., lid hygiene for blepharitis or systemic anti-TB drugs).

Question 214: A 7-year-old boy from a low socio-economic background presents with ocular complaints and nodules on the bulbar conjunctiva near the limbus. Phlyctenular conjunctivitis is diagnosed. Which of the following statements regarding phlyctenular conjunctivitis is true?

A. Hay fever is the most common cause.
B. Conjunctival edema is a characteristic feature.
C. Redness of the eye is a typical symptom.
D. Pain is rare. (Correct Answer)

Explanation: **Explanation:** **Phlyctenular Keratoconjunctivitis (PKC)** is a localized **Type IV hypersensitivity reaction** (delayed hypersensitivity) of the conjunctiva and cornea to endogenous microbial proteins. 1. **Why Option D is correct:** In simple phlyctenular conjunctivitis, the primary symptoms are mild irritation, lacrimation, and itching. **Pain is notably absent or rare** unless the phlyctenul (nodule) involves the cornea. When the lesion is limited to the bulbar conjunctiva, the patient experiences discomfort rather than significant pain. 2. **Why other options are incorrect:** * **Option A:** In developing countries like India, the most common cause is a hypersensitivity to **Tubercular protein (Tuberculin)**. In developed countries, it is more commonly associated with *Staphylococcus aureus* (cell wall proteins). Hay fever is associated with Type I hypersensitivity (Allergic Conjunctivitis), not PKC. * **Option B:** The hallmark of PKC is a **localized pinkish-white nodule** surrounded by a zone of hyperemia. Diffuse conjunctival edema (chemosis) is characteristic of acute allergic or gonococcal conjunctivitis, not phlyctenular disease. * **Option C:** While there is localized redness (hyperemia) around the nodule, "redness of the eye" as a generalized symptom is less characteristic than the focal nodular presentation. **Clinical Pearls for NEET-PG:** * **The Phlycten:** It is a sterile subepithelial infiltration of lymphocytes. It typically starts at the limbus. * **Fascicular Ulcer:** If the phlycten migrates towards the center of the cornea, it carries a leash of blood vessels behind it, forming a "wandering ulcer." * **Association:** Always screen for systemic Tuberculosis (Chest X-ray, Mantoux test) in a child presenting with PKC in the Indian subcontinent. * **Treatment:** Topical steroids (to control the hypersensitivity) and treatment of the underlying cause (e.g., ATT for TB or lid hygiene for Blepharitis).

Question 215: What is the most common cause of vision diminution in pterygium?

A. Obstruction of the visual axis
B. Corneal perforation
C. Myopia
D. Astigmatism (Correct Answer)

Explanation: **Explanation:** The most common cause of vision diminution in pterygium is **Astigmatism**. As the pterygium grows onto the cornea, it exerts mechanical traction and flattens the horizontal meridian of the cornea. This results in **with-the-rule (WTR) astigmatism**, leading to blurred vision even before the growth reaches the pupillary area. **Analysis of Options:** * **D. Astigmatism (Correct):** This occurs early in the disease process due to corneal warping and changes in the tear film stability. It is the most frequent reason patients seek refractive correction or surgery. * **A. Obstruction of the visual axis:** While a pterygium can grow large enough to cover the pupil and block light, this is a late-stage complication and is less common than the refractive changes that occur much earlier. * **B. Corneal perforation:** This is an extremely rare complication, usually only seen in cases of associated "Dellen" (localized thinning due to tear film instability) or secondary infections, but it is not a standard cause of vision loss in pterygium. * **C. Myopia:** Pterygium typically causes astigmatism, not a simple myopic shift. **High-Yield Clinical Pearls for NEET-PG:** * **Stockers Line:** A brownish line of iron deposition (hemosiderin) seen on the corneal epithelium at the leading edge (head) of a stable pterygium. * **Fuchs’ Striae:** Small whitish patches representing focal degeneration seen at the advancing edge. * **Surgical Gold Standard:** Wide excision with **Limbal Conjunctival Autograft (CAG)** is the treatment of choice to minimize the high recurrence rate. * **Indication for Surgery:** Visual impairment (due to astigmatism or axis obstruction), cosmetic disfigurement, or documented rapid growth.

Question 216: Which of the following statements about pterygium is true?

A. A probe can be passed underneath the pterygium at the limbus.
B. It is associated with exposure to infrared radiation.
C. The bare sclera technique has a 30-80% recurrence rate. (Correct Answer)
D. It involves elastotic degeneration with distortion of Descemet's membrane.

Explanation: **Explanation:** **Pterygium** is a wing-shaped, fibrovascular proliferation of the subconjunctival tissue that encroaches onto the cornea. 1. **Why Option C is Correct:** The **Bare Sclera Technique** involves simple excision of the pterygium, leaving the underlying sclera exposed. This method is notorious for high recurrence rates, ranging from **30% to 80%**. To reduce this, the current "gold standard" is **Conjunctival Autograft (CAG)**, which brings the recurrence rate down to 2–5%. 2. **Analysis of Incorrect Options:** * **Option A:** A probe **cannot** be passed underneath a true pterygium because it is adherent to the underlying structures at the limbus. This is the classic clinical test to differentiate it from a **pseudopterygium** (caused by chemical burns or trauma), where a probe can be passed underneath. * **Option B:** Pterygium is primarily associated with chronic exposure to **Ultraviolet (UV) radiation** (specifically UV-B), not infrared. It is common in the "Pterygium Belt" (latitudes 30° N and S of the equator). * **Option D:** While it involves **elastotic degeneration** of collagen, it affects the superficial layers (subconjunctival tissue and Bowman’s membrane). It does **not** involve Descemet’s membrane, which is a deep layer of the cornea. **High-Yield Clinical Pearls for NEET-PG:** * **Stocker’s Line:** An iron deposition line seen on the corneal epithelium at the leading edge of a pterygium (indicates stability). * **Fuchs’ Flecks:** Small greyish-white opacities seen at the head of the pterygium. * **Management:** Surgical excision is indicated if it causes visual impairment (due to astigmatism or covering the pupillary area) or cosmetic disfigurement. **Mitomycin-C** or **5-Fluorouracil** are sometimes used as adjuncts to prevent recurrence.

Question 217: New Castle conjunctivitis is caused by contact with diseased:

A. Dogs
B. Cats
C. Owls (Correct Answer)
D. Horses

Explanation: **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.

Question 218: A 20-year-old female is diagnosed with pterygium and has no clinical symptoms other than cosmetic concern. What is the recommended treatment?

A. Surgical excision
B. Observation (Correct Answer)
C. Antihistamines
D. Antibiotics

Explanation: **Explanation:** **1. Why Observation is the Correct Choice:** A pterygium is a triangular, fibrovascular proliferation of the subconjunctival tissue that extends onto the cornea. In this clinical scenario, the patient is **asymptomatic** and the primary concern is **cosmetic**. The standard management for a small, non-progressive, and asymptomatic pterygium is **observation** and reassurance. Surgical intervention is generally avoided in early stages because the recurrence rate is high (30-50% with bare sclera technique), and the recurrent lesion is often more aggressive than the primary one. **2. Why Other Options are Incorrect:** * **Surgical Excision:** This is indicated only if there is visual impairment (due to astigmatism or encroachment on the pupillary area), documented progression, or severe chronic irritation/restriction of ocular motility. It is not the first-line treatment for minor cosmetic concerns in a 20-year-old. * **Antihistamines:** These are used for allergic conjunctivitis (e.g., VKC). While they may relieve itching, they do not treat the fibrovascular growth of a pterygium. * **Antibiotics:** Pterygium is a degenerative/proliferative condition, not an infectious one; therefore, antibiotics have no role. **3. High-Yield Clinical Pearls for NEET-PG:** * **Etiology:** Strongly associated with **UV-B light exposure** and dry, dusty environments (Surfer’s Eye). * **Pathology:** Characterized by **Elastotic degeneration** of collagen. * **Stocker’s Line:** An iron deposition line (hemosiderin) seen on the corneal epithelium at the leading edge of the pterygium; it indicates the lesion is stable/long-standing. * **Surgical Gold Standard:** Excision with **Limbal Conjunctival Autograft (CAG)** is the preferred technique to minimize recurrence. * **Adjuvants:** Mitomycin-C or Beta-radiation may be used to reduce recurrence, though CAG is safer.

Question 219: Which of the following is NOT a feature of vernal conjunctivitis?

A. Shield ulcer
B. Horner-Tranta's spots
C. Papillary hypertrophy
D. Herpes pits, pannus & follicles (Correct Answer)

Explanation: **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.

Question 220: Pseudomembranous conjunctivitis is caused by which organism?

A. Neisseria gonorrhoeae
B. Staphylococcus aureus
C. Streptococcus pyogenes
D. All of the above (Correct Answer)

Explanation: **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.

Practice by Chapter

Conjunctivitis: Bacterial

Practice Questions

Conjunctivitis: Viral

Practice Questions

Conjunctivitis: Allergic

Practice Questions

Conjunctivitis: Chronic

Practice Questions

Degenerations of Conjunctiva

Practice Questions

Benign Tumors of Conjunctiva

Practice Questions

Malignant Tumors of Conjunctiva

Practice Questions

Conjunctival Manifestations of Systemic Diseases

Practice Questions

Cicatricial Conjunctival Disorders

Practice Questions

Pterygium and Pinguecula

Practice Questions

Conjunctival Trauma

Practice Questions

Subconjunctival Hemorrhage

Practice Questions

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