Diseases of the Conjunctiva — MCQs

Diseases of the Conjunctiva Indian Medical PG Practice Questions and MCQs

Question 151: Which of the following conjunctivitis can also involve the intact cornea?

A. Acute mucopurulent conjunctivitis
B. Acute membranous conjunctivitis
C. Acute purulent conjunctivitis (Correct Answer)
D. Angular conjunctivitis

Explanation: **Explanation:** The correct answer is **Acute purulent conjunctivitis** (also known as Hyperacute conjunctivitis). **1. Why the correct answer is right:** The hallmark of acute purulent conjunctivitis, most commonly caused by *Neisseria gonorrhoeae* or *Neisseria meningitidis*, is its ability to invade an **intact corneal epithelium**. Most bacteria require a pre-existing epithelial defect to cause a corneal ulcer; however, certain organisms possess virulent enzymes (proteases) that allow them to penetrate healthy corneal tissue directly. This can lead to rapid corneal perforation and endophthalmitis if not treated urgently. **2. Why the incorrect options are wrong:** * **A. Acute mucopurulent conjunctivitis:** Typically caused by *Staphylococcus aureus* or *Streptococcus pneumoniae*. While it causes significant discharge and "red eye," it does not involve the cornea unless there is prior trauma or severe drying. * **B. Acute membranous conjunctivitis:** Classically caused by *Corynebacterium diphtheriae*. While it can cause corneal scarring due to the severity of the inflammation and membrane formation, it does not typically penetrate an intact cornea as aggressively as *Neisseria*. * **C. Angular conjunctivitis:** Caused by *Moraxella axenfelditis*. It is characterized by excoriation of the skin at the inner and outer canthi due to proteases, but it does not involve the central cornea. **3. Clinical Pearls for NEET-PG:** * **Mnemonic for organisms that can penetrate intact cornea:** "**CHLNS**" * **C**orynebacterium diphtheriae * **H**aemophilus aegyptius * **L**isteria monocytogenes * **N**eisseria gonorrhoeae / meningitidis * **S**higella * **Treatment:** Purulent conjunctivitis due to *N. gonorrhoeae* is a medical emergency requiring systemic Ceftriaxone. * **Clinical Sign:** Look for "copious, thick, creamy pus" dripping from the eyelids.

Question 152: Circumcorneal congestion is seen in all of the following conditions, EXCEPT:

A. Anterior uveitis
B. Acute congestive glaucoma
C. Stevens-Johnson syndrome
D. Moraxella infection (Correct Answer)

Explanation: **Explanation:** The key to answering this question lies in differentiating between **Circumcorneal (Ciliary) Congestion** and **Conjunctival Congestion**. **Why Moraxella infection is the correct answer:** Moraxella lacunata typically causes **Angular Conjunctivitis**. This condition is characterized by **conjunctival congestion** (superficial vessels) localized specifically to the inner and outer canthi (angles) of the eye. It does not involve the deep ciliary vessels. Therefore, it presents with superficial redness rather than circumcorneal congestion. **Analysis of Incorrect Options:** Circumcorneal congestion involves the deep ciliary vessels and is a hallmark of **keratitis, iridocyclitis, or acute glaucoma**. * **Anterior Uveitis (Iridocyclitis):** Inflammation of the uveal tract triggers deep ciliary vessel engorgement, presenting as a typical dusky-red circumcorneal flush. * **Acute Congestive Glaucoma:** The sudden, massive rise in intraocular pressure leads to venous stasis and intense ciliary congestion. * **Stevens-Johnson Syndrome (SJS):** In the acute phase, SJS causes severe ocular surface inflammation, including intense conjunctivitis and often secondary keratitis or corneal involvement, which leads to circumcorneal congestion. **NEET-PG High-Yield Pearls:** 1. **Ciliary Congestion:** Vessels are deep, purple/dusky red, do not move with the conjunctiva, and do not blanch with 1:1000 adrenaline. It indicates serious intraocular pathology. 2. **Conjunctival Congestion:** Vessels are superficial, bright red, move with the conjunctiva, and **blanch with adrenaline**. It indicates superficial pathology (conjunctivitis). 3. **Moraxella Lacunata:** Classically associated with "maceration of the skin at the angles" due to the production of a proteolytic enzyme (protease). Treatment is Zinc Oxide or Oxytetracycline.

Question 153: Which of the following is NOT true about phlyctenular conjunctivitis?

A. It is an endogenous allergy.
B. It can be caused by Staphylococcus.
C. It is a Type II hypersensitivity reaction. (Correct Answer)
D. It is usually unilateral.

Explanation: **Explanation:** Phlyctenular conjunctivitis is a localized inflammation of the conjunctiva or cornea characterized by the formation of small nodules (phlyctens). **Why Option C is the correct answer (False statement):** Phlyctenular conjunctivitis is a **Type IV (Delayed-type) hypersensitivity reaction**, not Type II. It represents a cell-mediated immune response to endogenous microbial proteins to which the patient’s conjunctiva has been previously sensitized. **Analysis of other options:** * **Option A (True):** It is considered an **endogenous allergy** because the allergen is not an external factor (like pollen) but a protein derived from a microbe already present within the body. * **Option B (True):** Historically, *Mycobacterium tuberculosis* was the most common cause. However, in modern clinical practice, **Staphylococcus aureus** (specifically its cell wall proteins) is the most common causative agent. Other causes include Moraxella and certain fungi. * **Option D (True):** The condition is **usually unilateral** at presentation, although it can occasionally be bilateral or occur in crops. **High-Yield Clinical Pearls for NEET-PG:** * **The Phlycten:** A pinkish-white nodule surrounded by a localized zone of hyperemia. It typically occurs near the **limbus**. * **Fascicular Ulcer:** If a phlycten migrates towards the center of the cornea, it carries a leash of blood vessels behind it, forming a characteristic "serpiginous" or fascicular ulcer. * **Treatment:** Topical steroids are the mainstay of treatment to control the allergic response, along with treating the underlying cause (e.g., lid hygiene for Blepharitis or systemic workup for TB).

Question 154: What is the common cause of angular conjunctivitis?

A. Coronavirus
B. Adenovirus
C. Moraxella (Correct Answer)
D. Gonococci

Explanation: **Explanation:** **Angular Conjunctivitis** is a specific type of chronic conjunctivitis characterized by inflammation limited to the intermarginal strip at the outer or inner angles (canthi) of the eye, associated with excoriation of the surrounding skin. **Why Moraxella is the correct answer:** The most common causative organism is **Moraxella axenfeld** (also known as *Morax-Axenfeld bacillus*). The pathogenesis involves the production of a **proteolytic enzyme** (protease) by the bacteria. This enzyme acts by macerating the epithelium of the conjunctiva and the skin of the lid angles. In some cases, *Staphylococcus aureus* can also cause a similar clinical picture. **Analysis of Incorrect Options:** * **A & B (Coronavirus & Adenovirus):** These are viral causes. Adenovirus typically causes Follicular conjunctivitis (e.g., Pharyngoconjunctival fever or Epidemic Keratoconjunctivitis), characterized by watery discharge and follicles, rather than localized angular inflammation. * **D (Gonococci):** *Neisseria gonorrhoeae* causes Hyperacute Purulent Conjunctivitis (Ophthalmia Neonatorum in neonates), characterized by profuse, thick pus and a high risk of corneal perforation. **High-Yield Clinical Pearls for NEET-PG:** * **Clinical Feature:** Redness at the angles, itching, and a typical "smarting" sensation. * **Treatment of Choice:** **Zinc Oxide** drops or ointment. Zinc acts by neutralizing the proteolytic enzyme produced by Moraxella, thereby facilitating healing. * **Differential Diagnosis:** Must be distinguished from Vitamin B2 (Riboflavin) deficiency, which can also cause angular stomatitis and angular blepharitis.

Question 155: What is the most common cause of neonatal conjunctivitis?

A. Chlamydia (Correct Answer)
B. Chemical irritation
C. Gonococcus
D. Herpes simplex

Explanation: **Explanation:** **Ophthalmia Neonatorum** (neonatal conjunctivitis) is defined as any discharge or inflammation of the conjunctiva occurring within the first month of life. **Why Chlamydia is Correct:** * **Chlamydia trachomatis (Serotypes D-K)** is currently the **most common infectious cause** of neonatal conjunctivitis worldwide. * It typically presents **5 to 14 days** after birth. * The clinical presentation ranges from mild hyperemia to severe papillary conjunctivitis with pseudomembrane formation. Because neonates lack lymphoid tissue in the conjunctiva at birth, follicles are not seen (unlike in adults). **Analysis of Incorrect Options:** * **Chemical irritation:** Historically common due to Silver Nitrate (Credé’s prophylaxis), it appears within the **first 24 hours** and resolves spontaneously. It is the most common cause in the first day of life, but not overall. * **Gonococcus (Neisseria gonorrhoeae):** This is the **most hyperacute and vision-threatening** cause, appearing **2 to 5 days** after birth. It causes profuse purulent discharge and can penetrate an intact corneal epithelium. * **Herpes simplex (HSV-2):** A rare cause appearing **1 to 2 weeks** after birth, typically associated with vesicular skin lesions and dendritic keratitis. **High-Yield Clinical Pearls for NEET-PG:** 1. **Timeline is Key:** Chemical (24 hrs) → Gonococcal (2–5 days) → Chlamydia (5–14 days) → HSV (1–2 weeks). 2. **Treatment of Choice:** For Chlamydia, **Oral Erythromycin** (50 mg/kg/day for 14 days) is mandatory to treat the ocular infection and prevent Chlamydial pneumonia. 3. **Diagnosis:** Giemsa stain showing **Halberstaedter-Prowazek (HP) inclusion bodies** is characteristic of Chlamydia.

Question 156: Trachoma is characterized by which of the following?

A. Epithelial keratitis
B. The corneal lesion is pannus
C. Pits in the limbus in the late stage
D. Follicle formation is a late stage (Correct Answer)

Explanation: **Explanation:** Trachoma, caused by *Chlamydia trachomatis* (serotypes A, B, Ba, and C), is a chronic keratoconjunctivitis characterized by a specific progression of clinical signs. **Why Option D is Correct:** According to the **McCallan Classification**, Trachoma progresses through four stages. **Stage I (Incipient Trachoma)** involves immature follicles, while **Stage II (Established Trachoma)** is characterized by the presence of mature, large follicles (sago-grain appearance) and papillary hypertrophy. Therefore, follicle formation is a hallmark of the active, established stage of the disease. **Analysis of Incorrect Options:** * **A. Epithelial keratitis:** While superficial keratitis can occur, it is not the pathognomonic or primary characterizing feature of Trachoma compared to follicular conjunctivitis. * **B. The corneal lesion is pannus:** While "Trachomatous Pannus" (vascularization and infiltration of the upper cornea) is a classic sign, it is considered a complication/sequela rather than the primary characterizing lesion of the early/active disease process. * **C. Pits in the limbus in the late stage:** This is a distractor. **Herbert’s Pits** (depressions left by healed limbal follicles) are indeed seen in Trachoma, but they occur as a result of the healing of follicles, marking the transition to the cicatricial stage, not the primary characterizing feature of the disease itself in this context. **High-Yield NEET-PG Pearls:** * **WHO Simplified Grading (FISTO):** **F**ollicles, **I**ntense Inflammation, **S**carring, **T**richiasis, **O**pacity. * **Arlt’s Line:** Horizontal scarring of the superior palpebral conjunctiva. * **Herbert’s Pits:** Pathognomonic sign found at the limbus. * **SAFE Strategy:** **S**urgery, **A**ntibiotics (Azithromycin is the drug of choice), **F**acial cleanliness, **E**nvironmental improvement. * **Vector:** The common housefly (*Musca sorbens*).

Question 157: Acute hemorrhagic conjunctivitis is caused by which of the following viruses?

A. Adenovirus
B. Enterovirus-70
C. Coxsackie virus-A24
D. All of the above (Correct Answer)

Explanation: **Explanation:** **Acute Hemorrhagic Conjunctivitis (AHC)** is a highly contagious, self-limiting viral infection characterized by sudden onset, painful conjunctival inflammation, and prominent subconjunctival hemorrhages. **Why "All of the above" is correct:** AHC is primarily caused by three major viral agents. While **Enterovirus-70** and **Coxsackie virus-A24** (variants of Picornaviridae) are the most common causes of large-scale epidemics, specific serotypes of **Adenovirus** (particularly Serotypes 11 and 37) are also known to cause a clinically identical hemorrhagic presentation. Therefore, all three viruses listed are recognized etiological agents. **Breakdown of Options:** * **Enterovirus-70:** Historically the first virus identified in major AHC outbreaks (e.g., the 1969 pandemic). It is neurotropic and can rarely lead to polio-like paralysis (radiculomyelitis). * **Coxsackie virus-A24:** Currently the most frequent cause of AHC worldwide. It presents with similar ocular features but lacks the neurological complications associated with Enterovirus-70. * **Adenovirus:** While typically associated with Pharyngoconjunctival Fever (Types 3, 7) or Epidemic Keratoconjunctivitis (Types 8, 19, 37), certain strains specifically trigger hemorrhagic conjunctivitis. **High-Yield Clinical Pearls for NEET-PG:** * **Incubation Period:** Extremely short (12–48 hours). * **Key Sign:** Multiple petechial hemorrhages that coalesce to form large subconjunctival hemorrhages (usually starting in the upper bulbar conjunctiva). * **Systemic Association:** Enterovirus-70 is associated with **lumbar radiculopathy** and cranial nerve palsies. * **Management:** Supportive treatment only; topical steroids are generally contraindicated as they may prolong viral shedding.

Question 158: A chronic alcoholic complains of congestion around the lateral canthus and burning sensation with discomfort of the eyes. What is the probable diagnosis?

A. Adenoviral conjunctivitis
B. Apollo Disease
C. Angular conjunctivitis (Correct Answer)
D. Trachoma

Explanation: ### Explanation **Correct Answer: C. Angular conjunctivitis** **Medical Concept:** Angular conjunctivitis is characterized by inflammation specifically localized to the **angles of the eye** (lateral more common than medial canthus). It is classically caused by **Morax-Axenfeld bacillus** (*Moraxella lacunata*). The bacteria produce a proteolytic enzyme (protease) that macerates the skin and conjunctiva at the canthi. The association with **chronic alcoholism** is a high-yield clinical pointer. Alcoholics often suffer from **Pyridoxine (Vitamin B6) deficiency**, which predisposes the ocular epithelium to infection by *Moraxella*. The clinical presentation typically involves redness, excoriation of the skin at the outer canthus, and a "burning" sensation. **Why other options are incorrect:** * **Adenoviral conjunctivitis:** Typically presents with acute onset, watery discharge, and preauricular lymphadenopathy. It is usually diffuse rather than localized to the canthus. * **Apollo Disease (Acute Hemorrhagic Conjunctivitis):** Caused by Enterovirus 70 or Coxsackievirus A24. It presents with sudden onset, painful swelling, and characteristic subconjunctival hemorrhages. * **Trachoma:** Caused by *Chlamydia trachomatis* (Serotypes A, B, Ba, C). It primarily affects the superior palpebral conjunctiva, leading to follicles, Herbert’s pits, and eventual scarring (Arlt’s line). **High-Yield Clinical Pearls for NEET-PG:** * **Causative Organisms:** *Moraxella lacunata* (most common) and *Staphylococcus aureus*. * **Deficiency Link:** Often associated with **Vitamin B6 (Pyridoxine)** or **Zinc** deficiency. * **Treatment:** Topical **Zinc-based eye drops** (Zinc inhibits the proteolytic enzyme produced by Moraxella) and Oxytetracycline/Erythromycin ointment. * **Differential Diagnosis:** Always rule out **Blepharitis**, which involves the entire lid margin rather than just the angles.

Question 159: What is the most common cause of trichiasis?

A. Stye
B. Trachoma (Correct Answer)
C. Blepharitis
D. Congenital

Explanation: **Explanation:** **Trichiasis** is defined as the inward misdirection of eyelashes with a normal position of the lid margin. **Why Trachoma is the Correct Answer:** Trachoma, caused by *Chlamydia trachomatis* (serotypes A, B, Ba, and C), is the leading infectious cause of blindness worldwide and the **most common cause of trichiasis**. Chronic inflammation leads to subconjunctival fibrosis (Arlt’s line). As this scar tissue contracts, it pulls the lash follicles inward, resulting in cicatricial trichiasis. In the WHO "SAFE" strategy for trachoma control, the 'S' stands for Surgery to correct this specific complication. **Analysis of Incorrect Options:** * **Stye (Hordeolum Externum):** This is an acute suppurative inflammation of the Zeis or Moll glands. While it causes localized swelling and pain, it does not typically lead to permanent lash misdirection. * **Blepharitis:** Chronic posterior blepharitis can cause trichiasis due to long-term inflammation of the lid margin, but it is statistically less common than trachoma as a primary etiology in the context of global health and standard medical examinations. * **Congenital:** Congenital trichiasis is rare. It is often confused with **Epiblepharon**, where a redundant fold of skin pushes the lashes against the globe, rather than a primary misdirection of the follicles. **Clinical Pearls for NEET-PG:** * **Distinction:** Trichiasis (misdirected lashes, normal lid margin) vs. **Entropion** (inward turning of the entire lid margin). * **Complication:** The most serious complication of trichiasis is **corneal opacity/ulceration** due to mechanical abrasion (pseudoptysis). * **Treatment of Choice:** **Electrolysis** or **Cryotherapy** for few lashes; surgical lid procedures for multiple lashes. * **Arlt’s Line:** A horizontal scar in the upper palpebral conjunctiva, pathognomonic for Trachoma.

Question 160: Which of the following viruses does not cause conjunctivitis?

A. CMV (Correct Answer)
B. Adenovirus
C. Herpes simplex virus
D. Picornavirus

Explanation: **Explanation:** The correct answer is **A. CMV (Cytomegalovirus)**. **1. Why CMV is the correct answer:** While CMV is a member of the Herpesviridae family, it is primarily a **retinotropic** virus. In immunocompromised individuals (especially those with HIV/AIDS and CD4 counts <50 cells/µl), it causes **CMV Retinitis**, characterized by the classic "pizza-pie" or "cheese and ketchup" fundus appearance. CMV does not typically involve the conjunctiva or cause conjunctivitis. **2. Analysis of Incorrect Options:** * **Adenovirus (Option B):** The most common cause of viral conjunctivitis. It causes **Pharyngoconjunctival Fever (PCF)** (Serotypes 3, 4, 7) and **Epidemic Keratoconjunctivitis (EKC)** (Serotypes 8, 19, 37). * **Herpes Simplex Virus (Option C):** HSV-1 can cause primary blepharoconjunctivitis, typically presenting with unilateral follicular conjunctivitis and characteristic vesicular lesions on the lids. * **Picornavirus (Option D):** Specifically, **Enterovirus 70** and **Coxsackievirus A24** are the causative agents of **Acute Hemorrhagic Conjunctivitis (AHC)**, characterized by rapid onset, subconjunctival hemorrhages, and lid edema. **High-Yield Clinical Pearls for NEET-PG:** * **Follicular response:** The hallmark of most viral conjunctivitis (except CMV). * **Preauricular lymphadenopathy:** A key clinical sign of viral conjunctivitis (especially Adenovirus). * **Hutchinson’s Sign:** Vesicles on the tip of the nose indicating Herpes Zoster Ophthalmicus (Nasociliary nerve involvement), which carries a high risk of ocular complications. * **MC cause of Ophthalmia Neonatorum:** *Chlamydia trachomatis* (overall), but *N. gonorrhoeae* is the most hyperacute/destructive.

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free