Thyroid Disease — MCQs
Which of the following conditions is the most common complication of radioiodine treatment for Graves' disease?
Which of the following conditions is least likely to cause proptosis?
The most common cause of proptosis in adults:-
Dalrymple's sign of ocular Graves' disease refers to which of the following?
Retinitis pigmentosa is a feature of all except which of the following?
A patient presents with proptosis, restriction of eye movements, and is found to be euthyroid. What is the most likely diagnosis?
All are causes of proptosis except:
Which statement about inferior rectus is NOT true?
In a patient with AIDS, what typically causes chorioretinitis?
What is one of the most common complications of iridocyclitis?
Thyroid Disease Indian Medical PG Practice Questions and MCQs
Question 1: Which of the following conditions is the most common complication of radioiodine treatment for Graves' disease?
- A. Hypothyroidism (Correct Answer)
- B. Thyroid cancer
- C. Thyroid storm
- D. Subacute thyroiditis
Explanation: ***Hypothyroidism*** - **Radioiodine (RAI) therapy** destroys overactive thyroid cells, making it highly effective for Graves' disease but often leading to a permanent state of **hypothyroidism** post-treatment. - The goal of RAI is to eliminate the source of excess hormone production, and while effective, it frequently necessitates lifelong **thyroid hormone replacement**. *Thyroid storm* - **Thyroid storm** is a rare, life-threatening complication, usually seen in untreated or undertreated hyperthyroidism or during acute stress, not typically a direct outcome of effective RAI. - While a transient increase in thyroid hormones can occur shortly after RAI, a full-blown thyroid storm is infrequent with proper preparation and management. *Thyroid cancer* - There is no significant evidence to suggest an increased risk of **thyroid cancer** in adults following therapeutic doses of radioiodine for Graves' disease [1]. - The radiation dose is targeted primarily at the thyroid gland, and studies have shown no clear link to increased malignancy [1]. *Subacute thyroiditis* - **Subacute thyroiditis** (also known as de Quervain's thyroiditis) is typically a post-viral inflammatory condition of the thyroid, characterized by pain and tenderness in the thyroid gland [2]. - It does not directly result from radioiodine treatment; however, some patients may experience a transient inflammatory response (radiation thyroiditis) after RAI, which is usually mild and self-limiting, not true subacute thyroiditis.
Question 2: 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 3: The most common cause of proptosis in adults:-
- A. Preseptal cellulitis
- B. Capillary hemangioma
- C. Thyroid eye disease (Correct Answer)
- D. Orbital cellulitis
Explanation: ***Thyroid eye disease*** - **Thyroid eye disease (TED)**, also known as Graves' ophthalmopathy, is the most common cause of **proptosis** in adults. - It results from an autoimmune process leading to inflammation and expansion of the **extraocular muscles** and orbital fat, which pushes the eyeball forward. *Preseptal cellulitis* - **Preseptal cellulitis** is an infection of the eyelid and periorbital tissue anterior to the orbital septum, typically presenting with **eyelid swelling** and redness. - While it causes periorbital swelling, it generally does not cause true **proptosis**, which is the anterior displacement of the eyeball itself. *Capillary hemangioma* - **Capillary hemangiomas** are benign vascular tumors and are the most common orbital tumor in **infancy and childhood**, not adults. - They typically cause proptosis in young children, often presenting as a **reddish-blue mass** that may increase in size with crying. *Orbital cellulitis* - **Orbital cellulitis** is a serious infection of the tissues within the orbit, posterior to the orbital septum, which can cause **proptosis**, pain, and ophthalmoplegia. - While it is a cause of proptosis, it is an **acute infectious process** and not the most common overall cause of proptosis in the adult population compared to thyroid eye disease.
Question 4: Dalrymple's sign of ocular Graves' disease refers to which of the following?
- A. Retraction of the upper lid (Correct Answer)
- B. Lid lag
- C. Proptosis
- D. Convergence insufficiency
Explanation: ***Retraction of the upper lid*** - **Dalrymple's sign** specifically refers to the **wide-eyed stare** seen in **Graves' ophthalmopathy** due to **retraction of the upper eyelid**. - This symptom is caused by sympathetic overactivity of the **levator palpebrae superioris muscle**. *Lid lag* - **Lid lag (Graefe's sign)** is a different ocular sign where the **upper eyelid lags behind the globe** on downward gaze. - While also seen in **Graves' disease**, it is distinct from constant upper lid retraction. *Proptosis* - **Proptosis**, or **exophthalmos**, is the **forward protrusion of the eyeball** from the orbit. - This is a common feature of **Graves' ophthalmopathy**, but it is not what Dalrymple's sign refers to. *Convergence insufficiency* - **Convergence insufficiency (Moebius sign)** refers to the **inability to maintain convergence** during near vision. - While this can occur in **thyroid eye disease**, it is not Dalrymple's sign.
Question 5: Retinitis pigmentosa is a feature of all except which of the following?
- A. NARP
- B. Refsum's disease
- C. Hallervorden-Spatz disease (Correct Answer)
- D. Abetalipoproteinemia
Explanation: ***Hallervorden-Spatz disease*** - Also known as **Pantothenate kinase-associated neurodegeneration (PKAN)**, this disorder primarily causes **extrapyramidal symptoms** such as dystonia and parkinsonism due to iron accumulation in the basal ganglia. - While it is a neurodegenerative disorder affecting the brain, **retinitis pigmentosa** is not a characteristic feature of Hallervorden-Spatz disease. *Refsum's disease* - This is an **autosomal recessive peroxisomal disorder** characterized by the accumulation of **phytanic acid**, which is toxic to various tissues. - **Retinitis pigmentosa** is a classic symptom, often presenting with night blindness and progressive vision loss, along with **ataxia**, **polyneuropathy**, and **ichthyosis**. *NARP* - **NARP (Neuropathy, Ataxia, Retinitis Pigmentosa)** is a rare mitochondrial disorder caused by mutations in the **MT-ATP6 gene**, leading to energy production deficits. - **Retinitis pigmentosa** is a core feature, contributing to visual impairment, alongside **sensory neuropathy**, **ataxia**, and **developmental delay**. *Abetalipoproteinemia* - This is an **autosomal recessive disorder** characterized by the inability to synthesize **apolipoprotein B**, essential for the formation of chylomicrons and VLDL, leading to severe **malabsorption of fat-soluble vitamins** (A, D, E, K). - Prolonged deficiency of **vitamin E** can result in progressive neurological dysfunction, including **ataxia** and **retinitis pigmentosa**, due to oxidative damage to photoreceptors and nervous tissue.
Question 6: A patient presents with proptosis, restriction of eye movements, and is found to be euthyroid. What is the most likely diagnosis?
- A. Orbital cellulitis
- B. Orbital lymphoma
- C. Orbital pseudotumor (Correct Answer)
- D. Thyroid eye disease
Explanation: ***Orbital pseudotumor*** - **Orbital pseudotumor** (also known as idiopathic orbital inflammation) presents with **proptosis** and **restriction of eye movements**. - Typically presents with **acute or subacute onset** of **painful** ophthalmoplegia and proptosis. - It is a **diagnosis of exclusion** after ruling out other causes of orbital inflammation, including thyroid eye disease, orbital cellulitis, and orbital neoplasms. - **Euthyroid status** does not exclude this diagnosis, and it is the **most common painful orbital mass** in adults. *Orbital cellulitis* - **Orbital cellulitis** presents with **rapid onset** of **painful proptosis**, **chemosis**, **ophthalmoplegia**, and signs of **acute infection** (fever, periorbital erythema, recent sinusitis). - The absence of infectious signs and acute inflammatory markers makes this less likely. *Orbital lymphoma* - **Orbital lymphoma** typically presents with **slowly progressive, painless proptosis** in older patients. - It is a **chronic, indolent process** and less likely to cause acute, painful restriction of eye movements. - Usually presents as a palpable mass in the superotemporal orbit. *Thyroid eye disease* - **Thyroid eye disease** (Graves' ophthalmopathy) commonly causes **proptosis** and **restricted eye movements** due to extraocular muscle enlargement. - While **90% of TED patients have hyperthyroidism**, approximately **5% are euthyroid at presentation** (euthyroid Graves' ophthalmopathy). - However, TED typically has a **subacute to chronic onset**, bilateral involvement, lid retraction, and characteristic imaging findings (muscle belly enlargement sparing tendons). - The clinical presentation with acute symptoms and euthyroid state makes **orbital pseudotumor more likely** as the initial diagnosis.
Question 7: All are causes of proptosis except:
- A. Orbital cellulitis
- B. Orbital tumor
- C. Retinal detachment (Correct Answer)
- D. Graves' disease
Explanation: ***Retinal detachment*** - **Retinal detachment** is a condition where the retina separates from the underlying supportive tissue and does not cause proptosis. - Its primary symptoms include **flashes of light**, **floaters**, and a **curtain-like shadow** in the visual field. *Orbital cellulitis* - **Orbital cellulitis** is an infection of the fat and muscles around the eye, leading to inflammation and swelling. - This swelling can push the eye forward, causing **proptosis**. *Orbital tumor* - An **orbital tumor** is a mass growing within the orbit (eye socket), which occupies space and displaces the eyeball. - This displacement typically results in **proptosis**, often unilateral and progressive. *Graves' disease* - **Graves' disease** (or Graves' ophthalmopathy) involves inflammation and swelling of the extraocular muscles and orbital fat due to autoimmune processes. - This increased volume within the orbit directly causes **proptosis** and is often bilateral.
Question 8: Which statement about inferior rectus is NOT true?
- A. It is rarely involved in thyroid myopathy (Correct Answer)
- B. It is connected to the lower lid by Lockwood's ligament
- C. Its yoke muscle is superior oblique
- D. Actions are depression, adduction and extorsion
Explanation: ***It is rarely involved in thyroid myopathy*** - This statement is **NOT true**. The **inferior rectus** muscle is, in fact, one of the **most commonly affected extraocular muscles** in **thyroid eye disease (Graves' ophthalmopathy)**. - Involvement of the inferior rectus leads to **restrictive myopathy**, causing **diplopia** (especially on upward gaze) and **hypotropia**. *It is connected to the lower lid by Lockwood's ligament* - The **inferior rectus** muscle sheath is indeed connected to the lower eyelid through expansions that contribute to **Lockwood's ligament**, providing support to the globe. - This connection ensures the **lower lid moves with the globe** during downward gaze. *Its yoke muscle is superior oblique* - The **yoke muscle** for the **inferior rectus** is the **superior oblique** of the contralateral eye, as they work together to produce downward and outward gaze. - Their combined action helps maintain **binocular vision** in specific gaze positions. *Actions are depression, adduction and extorsion* - The primary action of the **inferior rectus** muscle is **depression** (moving the eye downwards). - Its secondary actions are **adduction** (moving the eye inwards) and **extorsion** (rotating the top of the eye outwards).
Question 9: In a patient with AIDS, what typically causes chorioretinitis?
- A. Cytomegalovirus (Correct Answer)
- B. Toxoplasma gondii
- C. Cryptococcus neoformans
- D. Histoplasma capsulatum
Explanation: **Explanation:** **1. Why Cytomegalovirus (CMV) is Correct:** Cytomegalovirus (CMV) retinitis is the **most common opportunistic ocular infection** in patients with AIDS, typically occurring when the CD4+ T-cell count falls below **50 cells/mm³**. It is a full-thickness necrotizing retinitis. The classic clinical appearance is described as **"Pizza-pie" or "Cheese and Ketchup" retinopathy**, characterized by areas of white retinal necrosis mixed with prominent retinal hemorrhages and vasculitis. **2. Why the Other Options are Incorrect:** * **Toxoplasma gondii:** While it causes chorioretinitis, it is less common than CMV in AIDS patients. It typically presents as a "headlight in the fog" appearance (focal retinitis with overlying vitritis). In AIDS, it often presents as a reactivation of a previous infection. * **Cryptococcus neoformans:** This primarily causes fungal meningitis. Ocular involvement is usually secondary to increased intracranial pressure (papilledema) or direct optic nerve infiltration, rather than primary chorioretinitis. * **Histoplasma capsulatum:** Causes "Presumed Ocular Histoplasmosis Syndrome" (POHS), characterized by "punched-out" chorioretinal scars, peripapillary atrophy, and maculopathy. It is not specifically associated with the immunosuppression levels seen in AIDS. **3. High-Yield Clinical Pearls for NEET-PG:** * **CD4 Count Threshold:** CMV Retinitis = CD4 < 50 cells/mm³. * **Drug of Choice:** **Ganciclovir** (Intravenous or Intravitreal implants). Foscarnet and Cidofovir are alternatives. * **Immune Recovery Uveitis (IRU):** A paradoxical inflammatory response occurring in AIDS patients after starting HAART as their CD4 count rises. * **Cotton Wool Spots:** These are the most common *non-infectious* ocular finding in AIDS (part of HIV microangiopathy), but they do not represent true chorioretinitis.
Question 10: What is one of the most common complications of iridocyclitis?
- A. Scleritis
- B. Secondary glaucoma (Correct Answer)
- C. Band-shaped keratopathy
- D. Corneal ulcer
Explanation: **Explanation:** **Iridocyclitis** (anterior uveitis) is characterized by inflammation of the iris and ciliary body. **Secondary glaucoma** is one of the most common and vision-threatening complications of this condition. It occurs via two primary mechanisms: 1. **Open-angle mechanism:** Inflammatory debris (cells, fibrin, and pigment) clogs the trabecular meshwork, or "trabeculitis" reduces outflow facility. 2. **Closed-angle mechanism:** Formation of **posterior synechiae** (adhesions between the iris and lens) leads to *seclusio pupillae*. This obstructs aqueous flow from the posterior to the anterior chamber, causing **iris bombé** and subsequent angle closure. **Analysis of Incorrect Options:** * **Scleritis (A):** This is an inflammation of the outer coat of the eye. While systemic diseases (like Rheumatoid Arthritis) can cause both uveitis and scleritis, one does not typically occur as a *complication* of the other. * **Band-shaped Keratopathy (C):** This is a classic complication of **chronic** uveitis (especially in Juvenile Idiopathic Arthritis) due to calcium deposition in Bowman’s layer. While common in chronic cases, secondary glaucoma occurs more frequently across both acute and chronic presentations. * **Corneal Ulcer (D):** This is typically caused by infection or trauma. Iridocyclitis may cause corneal edema or keratic precipitates (KPs), but it does not directly cause ulceration. **High-Yield Clinical Pearls for NEET-PG:** * **Most common cause of death in Uveitis:** Not applicable, but the most common cause of **blindness** in uveitis is **Cystoid Macular Edema (CME)**. * **Festooned Pupil:** Irregular pupil shape caused by patchy posterior synechiae; a hallmark of previous iridocyclitis. * **Treatment Note:** Atropine is used in iridocyclitis to provide ciliary rest and prevent the formation of posterior synechiae.
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