Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva Indian Medical PG Practice Questions and MCQs

Question 181: Which is the most common etiologic agent of Phlyctenular conjunctivitis?

A. Bacterial (Correct Answer)
B. Fungal
C. Protozoal
D. Tuberculous

Explanation: **Explanation:** **Phlyctenular Keratoconjunctivitis** is a localized **Type IV hypersensitivity reaction** (delayed hypersensitivity) of the conjunctiva and cornea to endogenous microbial proteins to which the tissues have become sensitized. 1. **Why Bacterial is correct:** Historically, *Mycobacterium tuberculosis* was the most common cause worldwide. However, in modern clinical practice and especially in developed regions, **Staphylococcus aureus** (bacterial) has emerged as the most common etiologic agent. The reaction is triggered by the bacterial cell wall proteins. 2. **Why Tuberculous is incorrect:** While Tuberculosis remains a significant cause in developing countries (and is often the second most common cause), it is no longer the leading agent globally compared to the prevalence of Staphylococcal blepharoconjunctivitis. 3. **Why Fungal and Protozoal are incorrect:** These organisms do not typically trigger the specific delayed hypersensitivity response seen in phlyctenulosis. Other rare causes include *Chlamydia*, *Coccidioides immitis*, and certain parasites, but they are statistically insignificant compared to bacterial triggers. **Clinical Pearls for NEET-PG:** * **The Phlycten:** Characteristically starts as a small, pinkish-white nodule surrounded by a zone of hyperemia, usually near the limbus. * **Pathology:** The nodule is a subepithelial infiltration of **lymphocytes and plasma cells**. * **Symptoms:** Intense photophobia and lacrimation occur if the cornea is involved (Fascicular ulcer). * **Treatment:** Topical steroids (to control the hypersensitivity) and treatment of the underlying cause (e.g., lid hygiene for Staphylococcal blepharitis or systemic ATT for Tuberculosis).

Question 182: Conjunctival xerosis is seen in all of the following except?

A. Steven-Johnson syndrome
B. Keratoconjunctivitis sicca
C. Vitamin A deficiency
D. Sarcoidosis (Correct Answer)

Explanation: **Explanation:** **Conjunctival Xerosis** refers to the dryness of the conjunctiva, which can be categorized into two types: **Parenchymatous xerosis** (due to local ocular disease/scarring) and **Epithelial xerosis** (due to systemic Vitamin A deficiency). **Why Sarcoidosis is the correct answer:** Sarcoidosis is a multisystem granulomatous disease that primarily affects the eye by causing **Uveitis** (most commonly chronic granulomatous anterior uveitis) and **Lacrimal gland enlargement**. While it can lead to dry eye (keratoconjunctivitis sicca) if the lacrimal glands are heavily infiltrated, it is not a classic or primary cause of conjunctival xerosis compared to the other options. In NEET-PG, Sarcoidosis is more frequently associated with "Mutton-fat" keratic precipitates and "Candle-wax drippings" on the retina. **Analysis of Incorrect Options:** * **Vitamin A Deficiency:** This is the most common cause of **Epithelial Xerosis**. Lack of Vitamin A leads to the loss of goblet cells and keratinization of the conjunctival epithelium, classically presenting with **Bitot’s spots**. * **Stevens-Johnson Syndrome (SJS):** This causes **Parenchymatous Xerosis**. Extensive scarring and destruction of goblet cells and accessory lacrimal glands lead to severe ocular surface dryness and symblepharon. * **Keratoconjunctivitis Sicca (KCS):** This is the clinical hallmark of dry eye syndrome. It involves a deficiency in the aqueous layer of the tear film, leading directly to xerotic changes of the ocular surface. **High-Yield Clinical Pearls for NEET-PG:** 1. **Bitot’s Spots:** Triangular, foamy, silvery-white patches on the bulbar conjunctiva; a pathognomonic sign of Vitamin A deficiency. 2. **Parenchymatous Xerosis** is also seen in Trachoma (Stage IV), Ocular Pemphigoid, and chemical burns. 3. **Schirmer’s Test:** Used to quantify tear production; <5mm in 5 minutes is diagnostic of severe dry eye.

Question 183: Which of the following is NOT a feature of Ocular Mucous Membrane Pemphigoid?

A. Loss of fornices
B. Lid: Trichiasis and Entropion
C. Involvement of oral mucosa
D. Type 1 hypersensitivity (Correct Answer)

Explanation: **Explanation:** **Ocular Mucous Membrane Pemphigoid (OMMP)** is a chronic, progressive, autoimmune cicatrizing conjunctivitis. The correct answer is **D (Type 1 hypersensitivity)** because OMMP is actually a **Type II hypersensitivity reaction**. It involves the formation of autoantibodies (IgG, IgA, or C3) against the basement membrane zone (specifically the BP180 protein) of the conjunctival epithelium, leading to subepithelial fibrosis. **Analysis of Options:** * **A. Loss of fornices:** This is a hallmark feature. Chronic inflammation leads to subepithelial scarring, which causes shortening of the conjunctival fornices and eventually leads to **symblepharon** (adhesion between palpebral and bulbar conjunctiva). * **B. Lid: Trichiasis and Entropion:** Cicatrization (scarring) of the palpebral conjunctiva causes the eyelid margin to turn inward (**entropion**), which subsequently causes the lashes to rub against the cornea (**trichiasis**). * **C. Involvement of oral mucosa:** OMMP is a systemic mucosal disease. The oral mucosa is the most common site of extraocular involvement (seen in ~90% of cases), often presenting as desquamative gingivitis. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnosis:** Confirmed by **Direct Immunofluorescence (DIF)** of a conjunctival biopsy showing linear deposition of antibodies at the basement membrane. * **End-stage:** Can lead to **Ankyloblepharon** (fusion of the lid margins) and total surface failure with corneal keratinization (xerosis). * **Management:** Systemic immunosuppression (e.g., Dapsone, Methotrexate, or Cyclophosphamide) is the mainstay of treatment to halt progression. Avoid surgery during the active inflammatory phase.

Question 184: Which of the following is NOT a corneal sign of trachoma?

A. Herpes follicles
B. Pannus
C. Opacity
D. Arlt's line (Correct Answer)

Explanation: **Explanation:** The question asks for the option that is **NOT** a corneal sign of trachoma. **1. Why Arlt’s Line is the Correct Answer:** Arlt’s line is a **conjunctival sign**, not a corneal sign. It is a horizontal band of scar tissue (cicatrization) typically found in the upper tarsal conjunctiva, running parallel to the lid margin at the junction of the anterior one-third and posterior two-thirds. It is a hallmark of the cicatricial stage of Trachoma (WHO Stage TS). **2. Analysis of Incorrect Options (Corneal Signs):** * **Herbert’s Pits (Option A - likely a typo for "Herbert's follicles"):** These are lymphoid follicles at the limbus. When they heal, they leave behind pathognomonic shallow depressions known as **Herbert’s pits**. These are considered corneal/limbal signs. * **Pannus (Option B):** Trachomatous pannus is an active vascularization and infiltration of the upper part of the cornea. It is a classic corneal involvement in the progressive stage. * **Opacity (Option C):** Chronic inflammation and pannus eventually lead to corneal opacification and scarring, which is a major cause of blindness in trachoma. **3. High-Yield Clinical Pearls for NEET-PG:** * **Causative Agent:** *Chlamydia trachomatis* (Serotypes A, B, Ba, and C). * **SAFE Strategy:** **S**urgery (for trichiasis), **A**ntibiotics (Azithromycin), **F**acial cleanliness, **E**nvironmental improvement. * **WHO Grading (FIST):** **F**ollicles, **I**ntense Inflammation, **S**carring (Arlt's line), **T**richiasis, Corneal **O**pacity. * **Pathognomonic Sign:** Herbert’s pits are the most specific corneal sign of past trachoma.

Question 185: Blepharitis acarica is caused by which of the following?

A. Streptococcus
B. Ascaris
C. Propionibacterium
D. Demodex folliculorum (Correct Answer)

Explanation: **Explanation:** **Blepharitis acarica** refers specifically to a chronic inflammation of the eyelid margins caused by an infestation of mites. **Why Demodex folliculorum is correct:** The term "acarica" is derived from *Acarina*, the subclass of arachnids that includes mites and ticks. **Demodex folliculorum** (found in hair follicles) and **Demodex brevis** (found in sebaceous/meibomian glands) are the primary causative agents. These mites reside at the base of the eyelashes, leading to mechanical blockage and delayed hypersensitivity reactions. A pathognomonic clinical sign of Demodex infestation is **cylindrical dandruff** (clear sleeves/collarettes) surrounding the base of the lashes. **Why the other options are incorrect:** * **A. Streptococcus:** This is a bacterium responsible for acute ulcerative blepharitis, characterized by yellow crusts and bleeding on removal, rather than parasitic infestation. * **B. Ascaris:** This is an intestinal nematode (roundworm). While it can cause systemic allergic manifestations, it does not cause blepharitis. * **C. Propionibacterium (Cutibacterium acnes):** This bacterium is often associated with acne vulgaris and chronic endophthalmitis but is not the primary cause of blepharitis acarica. **High-Yield Clinical Pearls for NEET-PG:** * **Pathognomonic Sign:** Cylindrical dandruff (collarettes) at the lash base. * **Symptoms:** Itching (worse in the morning), burning, and "madarosis" (loss of lashes). * **Treatment of Choice:** **Tea Tree Oil** (scrubs or 50% solution) is the most effective treatment as it kills the mites. Oral Ivermectin may be used in resistant cases. * **Associated Condition:** Strongly linked with **Ocular Rosacea**.

Question 186: Cicatrising trachoma is seen in which stage?

A. Stage 1
B. Stage 2
C. Stage 3 (Correct Answer)
D. Stage 4

Explanation: **Explanation:** Trachoma, caused by *Chlamydia trachomatis* (serotypes A, B, Ba, and C), is traditionally classified using the **McCallan Classification**, which divides the clinical course into four stages based on conjunctival changes. * **Stage 3 (Stage of Cicatrization):** This is the correct answer. This stage is characterized by the presence of **scarring (cicatrization)** of the palpebral conjunctiva. A hallmark finding here is **Arlt’s line**, a horizontal band of scarring located at the junction of the anterior one-third and posterior two-thirds of the tarsal conjunctiva. This scarring eventually leads to complications like trichiasis and entropion. **Analysis of Incorrect Options:** * **Stage 1 (Incipient Trachoma):** Characterized by immature follicles on the upper tarsal conjunctiva and early corneal changes (superficial keratitis). No scarring is present. * **Stage 2 (Established Trachoma):** Defined by mature follicles and papillary hypertrophy. It is the stage of active inflammation. * **Stage 4 (Stage of Sequelae):** This is the stage of "healed trachoma." The disease is inactive, and the patient presents with the late-stage consequences of scarring, such as corneal opacity and xerosis. **High-Yield Clinical Pearls for NEET-PG:** * **WHO Classification (FISTO):** Remember the mnemonic for active/chronic stages: **F**ollicular, **I**ntense inflammation, **S**carring, **T**richiasis, **O**pacity. * **Herbert’s Pits:** These are pathognomonic clinical signs of trachoma, representing scarred-down limbal follicles. * **Treatment:** The drug of choice is a single dose of **Azithromycin** (20 mg/kg). * **SAFE Strategy:** WHO-recommended strategy for control: **S**urgery, **A**ntibiotics, **F**acial cleanliness, **E**nvironmental improvement.

Question 187: Which of the following is NOT true regarding epidemic keratoconjunctivitis?

A. Enterovirus (Correct Answer)
B. Superficial punctate keratitis
C. Pseudomembrane formation
D. Subepithelial infiltrates

Explanation: **Explanation:** Epidemic Keratoconjunctivitis (EKC) is a highly contagious, severe form of viral conjunctivitis. **1. Why Enterovirus is the correct answer (The "NOT" true statement):** EKC is caused by **Adenovirus**, specifically serotypes **8, 19, and 37**. Enteroviruses (such as Enterovirus 70 and Coxsackievirus A24) are the causative agents of **Acute Hemorrhagic Conjunctivitis (AHC)**, which is characterized by rapid onset and prominent subconjunctival hemorrhages, rather than the chronic corneal involvement seen in EKC. **2. Analysis of other options:** * **Superficial Punctate Keratitis (SPK):** This is the initial corneal manifestation of EKC, occurring within the first week of infection due to active viral replication in the epithelium. * **Pseudomembrane formation:** Severe inflammation in EKC often leads to the formation of pseudomembranes (fibrinous exudate on the palpebral conjunctiva). If left untreated, these can lead to conjunctival scarring. * **Subepithelial Infiltrates (SEIs):** These are a hallmark of EKC, appearing around day 11–15. They represent an immune response to viral antigens and can persist for months, causing blurred vision and glare. **Clinical Pearls for NEET-PG:** * **Rule of 8:** EKC is often associated with Adenovirus type 8; symptoms typically appear 8 days after exposure; and the first 8 days are the most infectious. * **Preauricular Lymphadenopathy:** A classic clinical sign of viral conjunctivitis (including EKC). * **Treatment:** Primarily supportive. Topical steroids are reserved for vision-threatening SEIs or dense pseudomembranes but should be used cautiously as they may prolong viral shedding.

Question 188: Arlt's line is seen in which condition?

A. Vernal keratoconjunctivitis
B. Pterygium
C. Ocular pemphigoid
D. Trachoma (Correct Answer)

Explanation: **Explanation:** **Arlt’s line** is a classic clinical sign of **Trachoma**, a chronic keratoconjunctivitis caused by *Chlamydia trachomatis* (serotypes A, B, Ba, and C). It represents a horizontal band of scar tissue (cicatrization) located in the upper tarsal conjunctiva, specifically at the junction of the anterior one-third and posterior two-thirds. It occurs due to the healing of lymphoid follicles and chronic inflammation, leading to the contraction of the conjunctiva. **Analysis of Options:** * **Trachoma (Correct):** Characterized by the "SAFE" strategy. Arlt’s line is a hallmark of the cicatricial stage (WHO Stage: Trachomatous scarring - TS). * **Vernal Keratoconjunctivitis (VKC):** Associated with "cobblestone" papillae on the superior tarsal conjunctiva and Horner-Tranta’s dots at the limbus, but not linear scarring like Arlt’s line. * **Pterygium:** A degenerative condition involving a fibrovascular proliferation of the subconjunctival tissue onto the cornea (Stocker’s line may be seen here). * **Ocular Pemphigoid:** A chronic cicatrizing conjunctivitis that leads to symblepharon and ankyloblepharon, but the scarring is diffuse and involves the fornices rather than forming a specific horizontal line on the tarsus. **High-Yield Clinical Pearls for Trachoma:** 1. **Herbert’s Pits:** Small circular depressions on the limbus (pathognomonic) representing healed follicles. 2. **Sago-grain follicles:** Typical appearance of follicles in the upper tarsal conjunctiva. 3. **Pannus:** Vascularization of the upper part of the cornea. 4. **Entropion and Trichiasis:** Common late complications due to conjunctival scarring. 5. **Treatment:** Single dose of Oral Azithromycin (20 mg/kg) is the drug of choice.

Question 189: Herbert's pits are seen in which condition?

A. Trachoma (Correct Answer)
B. Spring catarrh
C. Phlyoutenular conjunctivitis
D. Sarcoidosis

Explanation: **Explanation:** **Herbert’s pits** are a pathognomonic clinical sign of **Trachoma**, a chronic keratoconjunctivitis caused by *Chlamydia trachomatis* (serotypes A, B, Ba, and C). They represent the late cicatricial stage of limbal follicles. During the active phase, lymphoid follicles form at the limbus; as these follicles heal, they undergo necrosis and are replaced by transparent fibrous tissue. This results in characteristic circular, shallow depressions or "pits" at the superior limbus. **Analysis of Incorrect Options:** * **B. Spring Catarrh (VKC):** Characterized by "cobblestone" papillae on the palpebral conjunctiva and **Horner-Trantas dots** (white limbal dots consisting of eosinophils and epithelial debris), not pits. * **C. Phlyctenular Conjunctivitis:** A type IV hypersensitivity reaction (often to Tubercular protein) presenting as a small, yellowish-grey nodule (phlycten) near the limbus, which may lead to a fascicular ulcer but not Herbert's pits. * **D. Sarcoidosis:** Can cause non-caseating granulomatous conjunctival nodules (often described as "mutton-fat" precipitates in the eye), but it is not associated with limbal follicular scarring. **High-Yield Clinical Pearls for NEET-PG:** * **Arlt’s Line:** Horizontal scarring of the superior palpebral conjunctiva (also seen in Trachoma). * **SAFE Strategy:** WHO-recommended management for Trachoma (**S**urgery, **A**ntibiotics—Azithromycin, **F**acial cleanliness, **E**nvironmental improvement). * **Pannus:** Trachomatous pannus is typically **superior** and progressive. * **Vector:** The common housefly (*Musca sorbens*) is the primary vector for transmission.

Question 190: Diagnosis of the given condition is:

A. Episcleritis
B. Bitot spots
C. Pterygium (Correct Answer)
D. Pinguecula

Explanation: ***Pterygium*** - A **triangular fibrovascular growth** that extends from the **conjunctiva onto the cornea**, crossing the **limbus** (junction between cornea and conjunctiva). - Typically grows from the **nasal side** and can cause **astigmatism** or **visual impairment** if it reaches the visual axis. *Episcleritis* - Presents as **localized redness** and **mild discomfort** without any growth or tissue proliferation. - It's a **vascular inflammation** of the episclera, not a fibrous growth extending onto the cornea. *Bitot spots* - Appear as **foamy, triangular patches** on the **bulbar conjunctiva** due to **vitamin A deficiency**. - They are **whitish-gray plaques** associated with **conjunctival xerosis**, not fibrovascular growths. *Pinguecula* - A **yellowish, elevated lesion** on the **bulbar conjunctiva** that does **not cross the limbus**. - It remains **confined to the conjunctiva** and does not extend onto the corneal surface like pterygium.

Practice by Chapter

Conjunctivitis: Bacterial

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Conjunctivitis: Viral

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Conjunctivitis: Allergic

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Conjunctivitis: Chronic

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Degenerations of Conjunctiva

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Benign Tumors of Conjunctiva

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Malignant Tumors of Conjunctiva

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Conjunctival Manifestations of Systemic Diseases

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Cicatricial Conjunctival Disorders

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Pterygium and Pinguecula

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Conjunctival Trauma

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Subconjunctival Hemorrhage

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