Orbital Diseases — MCQs

Orbital Diseases Indian Medical PG Practice Questions and MCQs

Question 131: A 5-year-old child presents with painless, progressive proptosis of the right eye. MRI reveals a mass in the right orbit. Which structure is most likely involved?

A. Optic nerve
B. Orbital fat
C. Lacrimal gland
D. Extraocular muscles (Correct Answer)

Explanation: ***Extraocular muscles*** - **Rhabdomyosarcoma**, a common orbital tumor in children, often arises from the **extraocular muscles** and presents with rapidly progressive, painless proptosis. - The location within the orbit and the clinical presentation in a child are highly suggestive of a tumor originating from these muscles. *Lacrimal gland* - **Lacrimal gland tumors** are rare in children and typically present as masses in the superotemporal orbit, potentially causing globe displacement rather than central proptosis. - More common in adults; specific tumors like pleomorphic adenoma or adenoid cystic carcinoma are seen. *Optic nerve* - **Optic nerve gliomas** are a possibility in children but usually cause **vision loss** and optic disc edema, which are not mentioned in this presentation. - They also tend to cause axial proptosis with optic nerve enlargement visible on imaging. *Orbital fat* - While the orbit contains fat, primary tumors arising from **orbital fat** itself are exceedingly rare. - Masses within the orbital fat are more likely to be extensions of other structures or inflammatory conditions.

Question 132: The globe is displaced to which side in lacrimal gland tumour?

A. Inferotemporal
B. Inferonasal (Correct Answer)
C. Nasal
D. Superotemporal

Explanation: ***Inferonasal*** - A lacrimal gland tumor is located in the **superotemporal** aspect of the orbit. - Due to its superior and temporal position, the tumor will displace the globe **inferiorly** and **nasally**. *Inferotemporal* - This displacement pattern would suggest an orbital mass originating from the **nasal** and **superior** quadrants (e.g., ethmoid sinus mucoceles extending superiorly and laterally), pushing the globe inferotemporally. - Lacrimal gland tumors are situated superotemporally, thus pushing the globe in the opposite direction. *Superotemporal* - This displacement would occur if a mass were located in the **inferonasal** quadrant of the orbit, which is not the typical location of a lacrimal gland tumor. - Lacrimal gland tumors originate from the superotemporal aspect, so they cannot displace the globe into their own position. *Nasal* - Pure nasal displacement is unlikely for a lacrimal gland tumor, as it is located **superotemporally**. - A mass located in the **lateral compartment** of the orbit would be more likely to cause nasal displacement.

Question 133: Axial proptosis is produced by tumors lying in:

A. Retrobulbar space (Correct Answer)
B. Subperiosteal space
C. Tenon space
D. Peripheral space

Explanation: ***Retrobulbar space*** - Tumors located in the **retrobulbar space**, directly behind the eyeball, push the globe forward along its axis, resulting in **axial proptosis**. - This is because the mass effect is exerted directly posteriorly to the globe, causing a straight-ahead protrusion. *Subperiosteal space* - Tumors in the **subperiosteal space**, located between the orbital bone and the periosteum, typically cause **non-axial proptosis** or displacement in other directions due to their peripheral location. - These lesions often lead to displacement in a direction away from the tumor, rather than direct axial protrusion. *Tenon space* - The **Tenon space** (or episcleral space) is a potential space between the globe and Tenon's capsule, which is a thin fibrous membrane. - Lesions here are usually very small and confined, causing minimal, if any, proptosis, and typically do not produce significant **axial proptosis**. *Peripheral space* - The term **peripheral space** is broad and usually refers to locations within the orbit that are not directly behind the globe (e.g., superolateral, inferomedial). - Tumors in peripheral orbital spaces commonly result in **non-axial proptosis**, displacing the eye in a specific direction corresponding to the tumor's location rather than pushing it straight forward.

Question 134: Most common malignant intraorbital tumor in adults is?

A. Lymphoma (Correct Answer)
B. Rhabdomyosarcoma
C. Sarcoma
D. Metastatic carcinoma

Explanation: ***Lymphoma*** - **Non-Hodgkin lymphoma** is the most common primary malignant intraorbital tumor in adults. - It often presents as a **slowly progressive mass** with proptosis and can originate from orbital lymphoid tissue. *Rhabdomyosarcoma* - This is the most common primary malignant orbital tumor in **children**, not adults. - It arises from rudimentary striated muscle cells and typically presents with rapid-onset proptosis. *Metastatic carcinoma* - While metastases to the orbit are common, they are typically **secondary lesions** originating from other primary sites (e.g., breast, lung), not primary intraorbital tumors. - They can present as discrete masses or diffuse infiltrations. *Sarcoma* - Sarcomas are a diverse group of malignant tumors of mesenchymal origin, but **rhabdomyosarcoma** is the most common specific type of sarcoma in the orbit, primarily in children. - Other types of sarcomas (e.g., osteosarcoma, fibrosarcoma) are rare in the adult orbit.

Question 135: Which of the following conditions is least likely to cause proptosis?

A. Sarcoidosis
B. Myxoedema (Correct Answer)
C. Grave's disease
D. Pituitary adenoma

Explanation: ***Myxoedema*** - **Myxoedema** is associated with severe **hypothyroidism** and is characterized by non-pitting edema due to the accumulation of **glycosaminoglycans** in tissues. - While it can cause facial puffiness, it is **least likely** to cause **proptosis** as there is no direct mechanism for an increase in orbital contents to push the eye forward. *Grave's disease* - **Grave's disease** is the most common cause of **proptosis** due to **immune-mediated inflammation** and accumulation of **glycosaminoglycans** and fat in the orbital tissues, leading to expansion. - This condition specifically affects the **extraocular muscles** and fat, causing bulging of the eyes. *Sarcoidosis* - **Orbital sarcoidosis** can cause **proptosis** due to the formation of **granulomas** within the orbit, leading to mass effect and inflammation. - It can affect any part of the eye and orbit, leading to varied clinical presentations including axial or non-axial globe displacement. *Pituitary adenoma* - A **pituitary adenoma** itself does not directly cause proptosis as it is located in the **sella turcica**, posterior to the orbits. - However, **large adenomas** can cause proptosis indirectly if they invade the **cavernous sinus** and obstruct venous return from the orbit, or if they are associated with **acromegaly**, which can lead to bony overgrowth of the orbital structures and surrounding tissues.

Question 136: In which condition is a positive forced duction test observed?

A. Mechanical restriction of ocular movement (Correct Answer)
B. Non-concomitant strabismus
C. No condition
D. Extraocular muscle paralysis

Explanation: ***Mechanical restriction of ocular movement*** - A **positive forced duction test** indicates a physical impediment to eye movement, meaning the eye cannot be passively moved beyond a certain point. - This test is crucial for differentiating between **muscle restriction** (e.g., thyroid eye disease, orbital floor fracture with muscle entrapment, post-surgical adhesions) and muscle weakness or paralysis. - When the examiner attempts to passively rotate the globe, there is **resistance** indicating mechanical tethering or restriction of the extraocular muscles. *Non-concomitant strabismus* - This refers to a squint where the magnitude of deviation varies with the direction of gaze. - While it can be caused by muscle restriction, non-concomitant strabismus itself is a **type of ocular misalignment**, not the specific finding of a forced duction test. - The forced duction test helps determine the **cause** of non-concomitant strabismus (mechanical vs. paralytic). *No condition* - This option is incorrect because a positive forced duction test specifically indicates mechanical obstruction or restriction in eye movement. - A positive result always points to an underlying pathological condition affecting ocular motility, not a normal finding. *Extraocular muscle paralysis* - In cases of **muscle paralysis**, the eye cannot move actively in the direction of the paralyzed muscle's action. - However, the **forced duction test would be negative** as the globe can be passively moved in all directions because there is no mechanical restriction. - This differentiates paralytic strabismus (negative test) from restrictive strabismus (positive test).

Question 137: What is the most common orbital tumor in children?

A. Nerve sheath tumor
B. Hemangioma (Correct Answer)
C. Lymphoma
D. Meningioma

Explanation: ***Hemangioma*** - **Capillary hemangioma** is the **most common benign orbital tumor/mass** in children, typically presenting in the first few months of life. - It is characterized by **rapid growth during the first year**, followed by **spontaneous involution** (usually complete by age 5-7 years). - These lesions are composed of rapidly proliferating endothelial cells and can cause **proptosis, ptosis**, and, if large, **amblyopia** due to visual axis obstruction or induced astigmatism. - Management is often conservative (observation) unless vision-threatening, in which case systemic steroids or propranolol may be used. *Nerve sheath tumor* - **Optic nerve sheath meningiomas** and **schwannomas** are rare in children, typically presenting in older adults. - While they can cause visual impairment and proptosis, their incidence in the pediatric population is significantly lower than hemangiomas. *Lymphoma* - **Orbital lymphoma** is exceedingly rare in children and is typically a tumor of adulthood, often associated with systemic lymphoma. - When it does occur in children, it might be a manifestation of a more widespread lymphoproliferative disorder. *Meningioma* - **Meningiomas** generally arise from arachnoid cap cells and are less common in children than in adults. - In children, they are more often associated with **neurofibromatosis type 2** and tend to be more aggressive.

Question 138: Most common orbital tumor has its origin from?

A. Blood vessels (Correct Answer)
B. Nerves
C. Muscle
D. Lymph node

Explanation: ***Blood vessels*** - The most common orbital tumor in childhood is a **capillary hemangioma**, which originates from blood vessels. - In adults, the most common primary orbital tumor is an orbital varix, also a **vascular lesion**. *Nerves* - Tumors of neural origin, such as **optic nerve gliomas** or **meningiomas**, are less common than vascular tumors. - While significant, they do not represent the *most* common overall origin for orbital tumors. *Muscle* - Tumors originating from muscle, such as **rhabdomyosarcoma** in children (a malignant tumor), are relatively rare. - **Pseudotumor** (idiopathic orbital inflammation), though common, is an inflammatory condition, not a true neoplasm of muscle origin. *Lymph node* - Tumors of lymphoid origin, such as **lymphomas**, are malignant and can occur in the orbit. - However, they are not the most common primary orbital tumor compared to those of vascular origin.

Question 139: Which muscle is the earliest to be involved in thyroid ophthalmopathy?

A. Medial Rectus (MR)
B. Inferior Rectus (IR) (Correct Answer)
C. Superior Rectus (SR)
D. Lateral Rectus (LR)

Explanation: ***Inferior Rectus (IR)*** - The **inferior rectus muscle** is most commonly and earliest affected in **thyroid ophthalmopathy** due to its anatomical location and muscle fiber type, making it highly susceptible to inflammation and edema. - Involvement of the inferior rectus leads to restricted **upward gaze** and **diplopia**, which are characteristic early symptoms of thyroid eye disease. *Medial Rectus (MR)* - While the **medial rectus** is often involved in thyroid ophthalmopathy, it is typically affected *after* the inferior rectus. - Dysfunction of the medial rectus manifests as difficulty with **adduction** (moving the eye inwards). *Superior Rectus (SR)* - The **superior rectus** is less frequently and usually later involved compared to the inferior and medial rectus muscles. - Its involvement typically causes restricted **downward gaze**. *Lateral Rectus (LR)* - The **lateral rectus** muscle is the *least common* ocular muscle to be affected in thyroid ophthalmopathy. - When affected, it primarily causes difficulty with **abduction** (moving the eye outwards).

Question 140: Massaging of nasolacrimal duct is done in ?

A. Acute dacryocystitis
B. Congenital dacryocystitis (Correct Answer)
C. Conjunctivitis
D. None of the options

Explanation: ***Congenital dacryocystitis*** - **Massaging the nasolacrimal duct** (Crigler massage) is a primary treatment for congenital dacryocystitis to promote the opening of the **valve of Hasner**. - This condition is due to incomplete canalization of the nasolacrimal duct, leading to tearing and discharge in infants. *Acute dacryocystitis* - This is an **acute infection of the lacrimal sac**, and massaging can worsen the condition by spreading the infection. - Treatment typically involves **antibiotics** and, if necessary, incision and drainage of any abscess. *Conjunctivitis* - **Conjunctivitis** is inflammation of the conjunctiva and is not related to obstruction of the nasolacrimal duct. - Massaging the nasolacrimal duct has no therapeutic role in treating conjunctivitis. *None of the options* - This option is incorrect because **congenital dacryocystitis** is a condition where nasolacrimal duct massage is a standard and effective treatment.

Practice by Chapter

Orbital Anatomy

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Orbital Imaging Techniques

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Orbital Inflammations

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Orbital Infections

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Orbital Tumors: Primary

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Orbital Tumors: Secondary

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Vascular Lesions of Orbit

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Thyroid Orbitopathy

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Orbital Trauma

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Congenital Orbital Anomalies

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Orbital Surgery Techniques

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Enucleation and Exenteration

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